Orthopaedic Surgery_ Principles of Diagnosis and Treatment.pdf

Orthopedic Surgery: Principles of Diagnosis and Treatm ent EDITORS

BRENT B. WIESEL, MD Chief, Shoulder Service Department of Orthopaedic Surgery Georgetown University Hospital/MedStar Health Washington, District of Colombia

WUDBHAV N. SANKAR, MD Assistant Professor of Orthopaedic Surgery Division of Orthopaedic Surgery The Children’s Hospital of Philadelphia Philadelphia, Pennsylvania

JOHN N. DELAHAY, MD Professor of Orthopaedic Surgery Department of Orthopaedic Surgery Georgetown University Hospital/MedStar Health Washington, District of Colombia

SAM W. WIESEL, MD Chair and Professor of Orthopaedic Surgery Department of Orthopaedic Surgery Georgetown University Hospital/MedStar Health Washington, District of Colombia

Executive Editor: Robert Hurley Developmental Editor: Sarah M. Granlund Vendor Manager: Bridgett Dough erty Product Manager: Dave Murphy Senior Manufacturing Manager: Ben Rivera Design Manager: Steph en Drudin g Marketing Manager: Lisa Lawren ce Compositor: Aptara, In c. 2011 by LIPPINCOTT WILLIAMS & WILKINS, a WOLTERS KLUWER business Two Commerce Square 2001 Market Street Philadelphia, Pa. 19103 USA LWW.co m C

All righ ts reserved. Th is book is protected by copyrigh t. No part of th is book m ay be reproduced in any form by any m eans, in cludin g ph otocopying, or utilized by any inform ation storage and retrieval system without written perm ission from the copyrigh t own er, except for brief quotation s em bodied in critical articles an d reviews. Materials appearing in this book prepared by individuals as part of th eir official duties as U.S. govern m en t employees are n ot covered by th e above-m entioned copyright. Prin ted in Ch in a Library of Congress Cataloging-in-Publication Data O rth opaedic surgery : principles of diagn osis an d treatm en t / editors, Bren t B. Wiesel . . . [et al.]. p. ; cm . Includes bibliograph ical references and index. ISBN 978-0-7817-9751-1 (hardback : alk. paper) 1. Orth opedic surgery. I. Wiesel, Bren t B. [DNLM: 1. Orth opedic Procedures. 2. Musculoskeletal Diseases–diagn osis. 3. Musculoskeletal Diseases–th erapy. WE 190] RD731.O7745 2010 617.4 7 –dc22 2010037456 Care has been taken to con firm the accuracy of the inform ation presented and to describe gen erally accepted practices. However, th e auth ors, editors, an d publish er are not responsible for errors or om ission s or for any consequences from application of th e inform ation in th is book an d m ake n o warran ty, expressed or im plied, with respect to the currency, completeness, or accuracy of th e contents of the publication. Application of th e in form ation in a particular situation rem ain s th e profession al respon sibility of the practitioner. Th e authors, editors, and publish er have exerted every effort to ensure that drug selection and dosage set forth in th is text are in accordance with current recom m endation s and practice at the tim e of publication. However, in view of on goin g research , ch an ges in govern m en t regulation s, an d th e con stan t flow of inform ation relating to drug therapy and drug reactions, th e reader is urged to check th e package in sert for each drug for any ch an ge in in dication s an d dosage an d for added warnings and precautions. This is particularly importan t wh en th e recom m ended agent is a new or in frequently employed drug. Som e drugs an d m edical devices presen ted in th e publication h ave Food an d Drug Adm in istration (FDA) clearan ce for lim ited use in restricted research settin gs. It is the responsibility of the health care provider to ascertain the FDA status of each drug or device plan n ed for use in th eir clin ical practice. To purchase addition al copies of th is book, call our custom er service departm en t at (800) 638-3030 or fax orders to (301) 223-2320. International custom ers should call (301) 223-2300. Visit Lippincott William s & Wilkins on th e Internet: at LWW.com . Lippin cott William s & Wilkin s custom er service represen tatives are available from 8:30 am to 6 pm , EST. 10 9 8 7 6 5 4 3 2 1

I dedicate this book to my wife, Katie, whose love, support, and patience over the past 10 years have made this possible. Also to my mentors in shoulder surgery: Charlie Getz, Mark Lazarus, Matt Ramsey, and Gerald Williams—it took 6 years and two institutions but you all can train anybody. -BBW I dedicate this book to my wife, Ariana, who constantly inspires me to be the best that I can be. She is and always will be my closest friend. Also to the best role model any young surgeon could ask for, Vernon Tolo. The strength of his Cobb is exceeded only by the size of his heart. Thanks for everything. -WNS I dedicate this effort to Maggie, Jack, Jimmy, Katie, Luke, Julia, Ryan, Brigid, and Ben and to their grandmother, Cathy, who keeps me sane when I am with them all. -JND I dedicate this book to my grandchildren: Anneliese Holland Wiesel, Sam Augustus Wiesel, and Maxwell Vickery Wiesel—they are giving their parents “hell” and I am enjoying every minute of it. They represent the future. -SWW

Contents Contributors vii Preface ix

1

Basic Science 1

10

Principles o f Ortho paedic Trauma 193 Samir Mehta

11

Pediatric Orthopaedics 235

Sectio n 1: Develo pment o f the Musculo skeletal System and the Growth Plate 1 John A. Zavala, John N. Delahay

Sectio n 1: General and Regio nal Problems in Children 235 Wudbhav N. Sankar, Karen Myung, Robert M. Kay

Sectio n 2: Basic Science o f Cartilage and Bo ne 11 John A. Zavala, John N. Delahay

Sectio n 2: Pediatric Spine 358 Wudbhav N. Sankar, David L. Skaggs

Sectio n 3: Bio mechanics and Bio materials 20 John A. Zavala, John N. Delahay

Sectio n 3: Pediatric Musculoskeletal Trauma 398 Wudbhav N. Sankar, John M. Flynn

2

Epidemio lo gy and Bio statistics in Ortho paedic Surgery 29 Keith D. Baldwin, G. Russell Huffman

12

The Spine 435 William Postma Steven, Scherping William Lauerman, Sam W. Wiesel

3

Imaging in Ortho paedic Surgery 39 Turner Vosseller, John N. Delahay

13

The Sho ulder 501 Brent B. Wiesel, Benjamin Shaffer, Gerald R. Williams

4

Electro diagno stic Testing 61 Michael K. Kuo

14

The Elbow 549 Brian Magovern, Matthew L. Ramsey

5

Musculo skeletal Infectio ns 79 Andrew F. Kuntz, John L. Esterhai

15

Hand and Wrist 583 Nick Pappas, Jonas L. Matzon, Pedro K. Beredjiklian

6

Metabo lic Bo ne Diseases 97 Aasis Unnanuntana, Brian P. Gladnick, Benjamin McArthur, Moira McCarthy, Joseph M. Lane

16

The Hip and Femur 653 Neil P. Sheth, J. Stuart Melvin, Charles L. Nelson, R. Bruce Heppenstall

7

Rheumato lo gy and Immuno lo gy fo r the Non-Rheumatologist 117 Daniel J. Clauw, Jacob N. Ablin

17

Knee and Leg Injuries 697 Todd Rimington, John Klimkiewicz, Freddie Fu

18

Knee Arthroplasty 735 John A. Johansen, Brian G. Evans

19

Fo o t and Ankle 753 Benjamin D. Martin, Francis X. McGuigan

8

9

Overview o f Musculo skeletal Neo plasms 145 Atul F. Kamath, Harish S. Hosalkar, Richard D. Lackman Principles o f Spo rts Medicine 165 F. Winston Gwathmey Jr., Joseph M. Hart, Mark D. Miller

Index 799

Contributors JACOB N. ABLIN, MD Intern al Medicine, Sackler School of

R. BRUCE HEPPENSTALL, MD Atten din g Orth opaedic Sur-

Medicine, Tel Aviv University; Director Fibromyalgia Clin ic, Departm en t of Rh eum atology, Sourasky Medical Cen ter, Tel Aviv, Israel

geon, Professor of Orthopaedic Surgery, Vice Chairm an of th e Departm en t of Orth opaedic Surgery, Hospital of th e Un iversity of Pen n sylvan ia, Philadelph ia, Pen n sylvania

KEITH D. BALDWIN, MD, MSPT, MPH Resident, Departm ent

HARISH HOSALKAR, MD Atten din g Orth opedic Surgeon , Co-

of Orth opaedic Surgery, Hospital of th e Un iversity of Pen n sylvania, Philadelphia, Pennsylvania

Director of In tern ation al Cen ter for Pediatric an d Adolescen t Hip Disorders, Director, Hip Research Program , Rady Ch ildren ’s Hospital, UCSD, San Diego, Californ ia

PEDRO K. BEREDJIKLIAN, MD Chief, Division of Hand

Surgery, Th e Roth m an In stitute; Associate Professor of Orth opaedic Surgery, Th om as Jefferson Un iversity Sch ool of Medicin e, Philadelphia, Penn sylvania DANIEL J. CLAUW, MD Professor of An esth esiology, Medicin e

(Rheum atology) and Psychiatry, University of Michigan, An n Arbor, Mich igan JOHN N. DELAHAY, MD Professor of Orth opaedic Surgery,

Departm en t of Orth opaedic Surgery, Georgetown Un iversity Hospital, Washington, District of Colom bia JOHN L. ESTERHAI, MD Professor, Departm en t of Orth o-

paedic Surgery, Hospital of th e Un iversity of Pen n sylvan ia, Un iversity of Pennsylvania School of Medicin e, Philadelph ia, Pen n sylvan ia BRIAN G. EVANS, MD Professor an d Vice Ch airm an of Oper-

ation s an d Fin an ce, Departm en t of Orth opaedic Surgery, Georgetown University Hospital, Washin gton, District of Colom bia JOHN M. FLYNN, MD Associate Ch ief of Orth opaedic

Surgery, Ch ildren ’s Hospital of Ph iladelph ia, Ph iladelph ia, Pen n sylvan ia FREDDIE FU, MD Professor an d Ch air of th e Departm en t of

Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, Pen n sylvan ia BRIAN P. GLADNICK, MD Resident, Departm ent of Orth o-

paedic Surgery, Hospital for Special Surgery, New York, New York F. WINSTON GWATHMEY JR., MD Resident, Departm ent

of Orth opaedics, Un iversity of Virgin ia, Ch arlottesville, Virgin ia JOSEPH M. HART, PhD, ATC Assistan t Professor of Orth o-

paedic Surgery, Departm ent of Orth opaedics, Un iversity of Virgin ia, Ch arlottesville, Virgin ia

G. RUSSELL HUFFMAN, MD, MPH Assistan t Professor, Sh oul-

der an d Elbow Division , Departm en t of Orth opaedic Surgery, Hospital of th e Un iversity of Pen n sylvan ia, Ph iladelph ia, Pen n sylvan ia JOHN A. JOHANSEN, MD Chief Resident, Georgetown Uni-

versity Hospital, Departm ent of Orthopaedic Surgery, Washington , District of Colom bia ATUL F. KAMATH, MD Clin ical In structor, Departm en t of Or-

th opaedic Surgery, Hospital of th e Un iversity of Pen n sylvan ia, Ph iladelph ia, Pennsylvan ia ROBERT M. KAY, MD Associate Professor, Departm en t of Or-

th opaedic Surgery, Keck-Un iversity of South ern Californ ia Sch ool of Medicin e; Vice Ch ief, Departm en t of Pediatric Orthopaedics, Children ’s Hospital Los Angeles, Los Angeles, Californ ia JOHN KLIMKIEWICZ, MD Ch ief, Division of Sports Medicin e,

Departm en t of Orth opaedic Surgery, Georgetown Un iversity Hospital, Wash ington , District of Colom bia ANDREW F. KUNTZ, MD Residen t, Departm ent of Or-

th opaedic Surgery, Hospital of th e Un iversity of Pen n sylvan ia, Ph iladelph ia, Pen n sylvan ia MICHAEL K. KUO, MD Assistan t Professor, Departm en t of

Reh abilitation Medicine, Georgetown University Hospital, Washington, District of Colom bia RICHARD D. LACKMAN, MD Professor an d Ch ief, Orth o-

paedic On cology, Departm en t of Orth opaedic Surgery, Un iversity of Pen n sylvan ia, Ph iladelph ia, Pen n sylvan ia JOSEPH M. LANE, MD Professor of Orth opaedic Surgery,

Weill Corn ell Medical College; Ch ief, Metabolic Bon e Disease Service, Departm en t of Orth opaedics, Hospital for Special Surgery, New York, New York

viii

Contributors

WILLIAM LAUERMAN, MD Professor, Departm en t of Or-

MATTHEW L. RAMSEY, MD Sh oulder an d Elbow Service, Th e

th opaedic Surgery, Georgetown Un iversity Hospital, Wash ington, District of Colom bia

Rothm an Institute; Associate Professor of Orth opaedic Surgery, Jefferson Medical College, Th om as Jefferson Un iversity, Philadelphia, Pennsylvania

BRIAN MAGOVERN, MD Clin ical In structor, Harbor-UCLA

Medical Center; Private Practice, Orthopaedic Institute, Torran ce, Californ ia

TODD RIMINGTON, MD Resident, Departm ent of Ortho-

BENJAMIN D. MARTIN, MD Chief Resident, Departm ent of

paedic Surgery, Georgetown Un iversity, Wash in gton , District of Colom bia

Orthopaedic Surgery, Georgetown University Hospital, Washington , District of Colom bia

WUDBHAV N. SANKAR, MD Assistan t Professor of Orth o-

JONAS L. MATZON, MD Ch ief Residen t, Departm en t of Or-

paedic Surgery, Ch ildren ’s Hospital of Ph iladelph ia, Ph iladelph ia, Pen n sylvan ia

th opaedic Surgery, University of Pen n sylvan ia, Ph iladelph ia, Pen n sylvan ia BENJAMIN A. MCARTHUR, MD Resident, Departm ent of Or-

th opaedics, Hospital for Special Surgery, New York, New York MOIRA M. MCCARTHY, MD Resident, Deparm ent of Or-

th opaedics, Hospital for Special Surgery, New York, New York FRANCIS X. MCGUIGAN, MD Professor, Departm en t of Or-

th opaedic Surgery, Georgetown Un iversity Medical Sch ool, Washington , District of Colom bia SAMIR MEHTA, MD Assistan t Professor, Un iversity of Pen n -

sylvania Sch ool of Medicine; Chief, Orthopaedic Traum a & Fracture Service, Hospital of th e Un iversity of Pen n sylvan ia, Ph iladelph ia, Pen nsylvan ia J. STUART MELVIN, MD Resident, Departm ent of Orth o-

paedic Surgery, Un iversity of Pen n sylvan ia, Hospital of th e University of Penn sylvania, Philadelphia, Pen nsylvan ia MARK D. MILLER, MD S. Ward Casscells Professor of Or-

th opaedic Surgery, Head, Division of Sports Medicin e, Un iversity of Virginia Departm ent of Orthopaedic Surgery; Ch arlottesville, Virginia: Team Physician , Jam es Madison University KAREN MYUNG, MD, PhD Assistan t Professor of Orth opaedic

Surgery, Ch ildren ’s Hospital Los An geles, Assistan t Professor of Orthopaedic Surgery, Departm ent of Orth opaedic Surgery, Un iversity of South ern Californ ia Keck Sch ool of Medicin e, Los An geles, Californ ia CHARLES L. NELSON, MD Atten din g Orth opaedic Surgeon ;

Associate Professor, Hospital of th e Un iversity of Pen n sylvan ia, Ph iladelphia, Pennsylvania

STEVEN SCHERPING, MD Departm en t

of O rth opaedic Surgery, Georgetown Un iversity Hospital, Wash in gton , District of Colom bia

BENJAMIN SHAFFER, MD Washington O rthopaedics and

Sports Medicin e, Wash in gton , District of Colom bia NEIL P. SHETH, MD Resident, Departm ent of Orthopaedic

Surgery, Un iversity of Pen n sylvan ia, Hospital of th e Un iversity of Pen nsylvan ia, Philadelphia, Pennsylvania DAVID L. SKAGGS, MD Professor of O rth opaedic Surgery,

Un iversity of South ern Californ ia Sch ool of Medicin e; Chief of Orth opaedic Surgery and Endpwed Ch air of Pediatric Spinal Disorders, Children ’s Hospital Los Angeles, Los An geles, Californ ia AASIS UNNANUNTANA, MD Fellow, Departm en t of Orth o-

paedic Surgery, Weill Corn ell Medical College; Fellow, Departm en t of Orth opaedic Surgery, Hospital for Special Surgery, New York, New York TURNER VOSSELLER, MD Fellow, Foot an d An kle Surgery,

Hospital for Special Surgery, New York, New York SAM W. WIESEL, MD Professor of Orth opaedic Surgery, Ch air

Deptartm en t of Orth opaedic Surgery, Georgetown Un iversity Hospital, Washin gton, District of Colom bia BRENT B. WIESEL, MD Chief, Shoulder Service, Departm ent

of Orth opaedic Surgery, Georgetown Un iversity Hospital/ MedStar Health, Washington, District of Colom bia GERALD R. WILLIAMS JR., MD Professor, Departm en t of Or-

Surgery, Un iversity of Pen n sylvan ia, Ph iladelph ia, Pen n sylvan ia

th opaedic Surgery, Jefferson Medical College; Ch ief, Sh oulder an d Elbow Service, Th e Roth m an In stitute at Jefferson , Thom as Jefferson University Hospitals, Philadelphia, Penn sylvania

WILLIAM F. POSTMA, MD Residen t, Departm en t of Ortho-

JOHN A. ZAVALA, MD Ch ief Residen t, Departm en t of Or-

paedic Surgery, Georgetown Un iversity Hospital, Wash in gton, District of Colom bia

th opaedic Surgery, Georgetown Un iversity Hospital, Wash in gton , District of Colom bia

NICK PAPPAS, MD Resident, Departm ent of Orth opaedic

Preface Th e goal of th is book is to create a compreh en sive, readable resource for orthopedic residents during the early years of th eir train in g. We en vision Principles as a book that in tern s can read from cover to cover durin g th e course of their PGY1 year to gain a broad base of knowledge before they start their orth opedic rotations. The individual subspecialty chapters will again be h elpful during th eir PGY2 an d PGY3 years as a con cise review of an en tire subspecialty that they can read prior to starting a n ew rotation . Th e book is divided in to two section s. Th e gen eral prin ciples portion presen ts orth opedic basic scien ce in sufficien t detail to prepare th e reader for th e in -train in g an d board exam in ation s. It con tain s ch apters on th e basics of th e various m odalities com m only used for patient evaluation in orth opedics an d th e evaluation an d treatm en t of m usculoskeletal infection, m etabolic bone disease, an d m usculoskeletal oncology. In addition, an overview of rheum atologic diseases affecting th e m usculoskeletal system an d the prin ciples guidin g th e treatm en t of orth opedic traum a an d sports m edicine patients are included. In th e subspecialty section , each ch apter addresses th e functional anatomy, patient evaluation (history, physical exam in ation , an d im agin g), traum atic in juries, an d atraum atic con ditions for a specific region of the body. For each diagn osis, th e typical presen tation , option s for n on oper-

ative an d operative m an agem en t, an d expected outcom es are discussed. Creating a text of this size always requires the assistance of a several creative an d capable people. We would first like to th an k Bob Hurley, Dave Murphy, an d Eileen Wolfberg at Lippin cott William s & Wilkin s wh ose h elp an d support h ave been in valuable in tran sform in g th is project from a on e-page proposal in to a n early 1,000-page book. We h ave also h ad th e privilege of workin g with a n um ber of orth opedic an d n on orth opedic colleagues th rough out the country. For each chapter, we h ave sough t to include at least on e jun ior an d on e sen ior auth or. Th e jun ior auth ors h ave either recen tly completed or are in th e fin al years of their training and are in cluded to m ake sure the in form ation is presen ted at a level th at will be un derstan dable by jun ior residen ts. Th e sen ior auth ors, m any of wh om are leaders in th eir fields, are in cluded to assure th at th e in form ation is accurate an d up to date. We are very appreciative of all of th eir con tribution s an d h ope th e book provides each reader with a stron g foun dation in th e fun dam en tals of orth opedics. Brent B. Wiesel, MD Wudbhav N. Sankar, MD John N. Delahay, MD Sam W. Wiesel, MD

1

Basic Science Sectio n 1

Develo pment o f the Musculo skeletal System and the Growth Plate John A. Zavala

John N. Delahay

INTRODUCTION A thorough understanding of genetics, em bryology, and postn atal developm en t of th e m usculoskeletal system is needed to engage in a discussion of m usculoskeletal an om alies. Approxim ately 5% of babies are born with som e type of con genital defect. Many defects require a period of growth an d developm en t before th ey becom e apparent. An appreciation of n orm al developm ent of the m usculoskeletal system is integral to a m ore complete un derstan din g of th ese con gen ital defects of th e m usculoskeletal system . O n e of th e m ost well-studied areas of m usculoskeletal developm en t is th e physis or growth plate. A th orough un derstan din g of th is structure is essen tial for th e treatm en t of m any pediatric orth opaedic diseases and fractures. Furth erm ore, m any of th e biologic processes th at naturally create bon e in th e growin g skeleton are curren tly bein g explored for m anipulation in an attempt to improve bone healing in problem atic adult fractures.

GENETICS Although there have been m ore than 3000 genetic disorders iden tified, very few gen es are respon sible for m usculoskeletal diseases. Most genetic diseases fall into one of three categories. The first group consists of isolated gene defects th at are govern ed by th e prin ciples of Men delian in heritan ce. Ch rom osom al abnorm alities, such as deletions an d translocation, are included in the second group. Lastly, a heterogeneous group of polygenic defects are th e result of an in terplay between gen etic an d en viron m en tal factors. Gen etic defects can presen t at any age from in fan cy to adulthood. Th e prevalence of genetic defects will also vary

widely. It is important to perform a careful fam ily history an d fam ily pedigree in th e complete evaluation of a ch ild with a gen etic abnorm ality. Genetic counseling, the determ in ation of in h eritan ce pattern s, an d an assessm en t of th e likelih ood th at siblin gs will be affected all depen d on th is in form ation . Th e com m on pattern s of Men delian in h eritan ce are specifically predicated upon the presence or absence of an abn orm al gen e on a ch rom osom e. Pattern s m ay be dom in an t, requirin g on ly a sin gle allele to express th e trait, or recessive, requirin g th e expression of both alleles. Th e four pattern s th at are typically seen are autosom al dom in an t, autosom al recessive, X-lin ked dom in an t, an d X-lin ked recessive. Autosom al dom in an t in h erited con dition s typically produce n on fatal structural abn orm alities. Heterozygotes will express the con dition. Expression of a genetic trait suggests a wide variation in the severity of the m anifestation. Th ere is n o m ale/ fem ale preferen ce, an d h alf of the offspring will be affected (Fig. 1.1). Gen erally, autosom al recessive con dition s ten d to be en zym atic defects (in born errors of m etabolism ). Both alleles m ust be abn orm al for th e con dition to be expressed; th erefore, on ly hom ozygotes can express the condition . It is possible for paren ts to be unaffected but carriers of the gene. Twenty-five percent of offspring are affected, an d there is n o m ale/ fem ale predom inan ce (Fig. 1.2). X-linked conditions are described as being either dom in an t or recessive. In X-lin ked dom in an t con dition s, th e h eterozygote m an ifests the con dition , but it is th e affected m oth er wh o tran sm its th e X-lin ked gen e to 50% of h er daugh ters an d 50% of h er son s. An affected fath er will tran sm it th e gen e to 100% of h is daugh ters an d n on e of h is son s. Male ch ildren typically h ave m ore severe involvem en t th an do fem ales. In X-lin ked recessive con dition s, th e

2

Orthopaedic Surgery: Principles of Diagnosis and Treatment

Figure 1.1 Autosomal dominant pedigree. Men are indicated

Figure 1.3 X-linked recessive pedigree. Affected hemizygous

fem ale hom ozygote will be a carrier for th e disease (Fig. 1.3). Because m ales h ave only one Xchrom osom e th ey will be affected by th e con dition s. Affected fath ers will tran sm it the gene to all their daughters, who will be carriers. Carrier fem ales will transm it the gen e to 50% of th eir daugh ters, wh o will be carriers, an d all of th eir son s. Importan t diseases to rem em ber in th is category are h em oph ilia an d Duch en n e’s m uscular dystrophy. Polygenic inheritan ce occurs in the setting of m ultiple gen es th at in teract with en viron m en tal factors to produce a given trait. The Gaussian curve (Fig. 1.4) is used to depict what has been referred to as “th e th reshold of risk” in a given population . If th ere is a first-degree relative wh o h as a given trait, such as scoliosis, th ere is clearly an increased risk for oth er relatives to m anifest the trait. This can be represen ted by a sh ift of th e curve or a lowerin g of th e threshold. The thresh old of risk is affected by race, sex, and to som e degree by geography.

Th e th ird category of gen etic disease results from rearran gem en ts within a given chrom osom e. These abnorm alities can include extra chrom osom es, referred to as “trisomy, or partial or complete loss of a chrom osom e.” In addition , m osaics and translocation s can be grouped under th is h eadin g. Many of th ese ch rom osom al abn orm alities result in spon tan eous abortion s. It h as been estim ated th at approxim ately 1% of live-born children have som e type of chrom osom al aberration. Trisomy 21 (Down syndrom e) is the m ost com m on disease in th is category with an in cidence of 1 per 700 live birth s.

by squares and women by circles. Filled symbols indicate clinically affected individuals. (Reprinted with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

men are indicated by filled squares. Asymptomatic female carriers are indicated by half-filled circles. (Reprinted with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

ORTHOPAEDIC EMBRYOLOGY Intramembranous and Enchondral Ossification All bon es of the m usculoskeletal system begin as m esen chym al con den sation s from a prim ary germ layer with m ultiple m echanical an d chem otactic factors actively influencing the cellular differen tiation. These con densations of cells typically form bon e in on e of two ways. In tram em bran ous bon e form ation occurs with th e con den sation of

NUMBER OF INDIVIDUALS

THRESHOLD OF RISK

Figure 1.2 Autosomal recessive pedigree. Homozygous af-

fected individuals are indicated by filled symbols. Asymptomatic carriers, who are heterozygotes, are indicated by half-filled symbols. (Reprinted with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

LIABILITY TO DISEASE (GENETIC & ENVIRONMENTAL)

Figure 1.4 Gaussian curve: depiction of polygenic inheritance.

Chapter 1: Basic Science

A

B

C

3

D

Figure 1.5 Normal limb rotation. A: At 48 days, the hand and foot plates face each other.

B: At 51 days, elbows are bent laterally. C: At 54 days, the soles of the feet face each other. D: The lateral rotation of the arms and medial rotation of the legs result in caudally facing elbows and cranially facing knees. (Reprinted with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

m esen chym al cells. They produce a m ucoprotein m atrix in wh ich collagen becom es em bedded. Subsequen t m in eralization converts the anlage to bone without an interm ediate cartilage step. Th e second way is the m ore classic ench ondral ossification wh ere bon e replaces a cartilage m odel. In tram em bran ous bon e form ation is well dem on strated by the example of th e calvarium of the skull. Th is process involves the direct elaboration by osteoblasts of bone m atrix with out a cartilage template. In itially a sm all group of cells aggregate, divide, and form random cords of cells. These cells are high in alkaline phosphatase, and as one would expect, rapid calcification occurs an d subsequen t ossification form s prim ary trabecular bone. Intram em branous form ation is also respon sible for the appositional growth of long bon es. Th e lon g bon es of th e skeleton form by th e process of en ch on dral ossification . Th e m ajor com pon en ts origin ate from the m esoderm al layer of the trilam inar em bryo. On e can trace the developm ent of the m ajor long bon es through the en chon dral process. The prim itive lim b bud appears around the fifth week of em bryonic life (Fig. 1.5). It is about that tim e that a tubular condensation of m esenchym e develops centrally in the lim b bud. During th e sixth week, the m esen chym e differentiates into cartilage through th e process of chon drification. Both interstitial and appositional growth occurs. In th e seven th week, th e cartilage m odel is pen etrated by a vascular spindle, and subsequently, a sleeve of prim itive bone is seen surrounding it. Progressively, necrosis of th e central cartilage occurs. On ce th is vascular spindle is established, the central portion of the m odel is populated by osteoblasts. As m atrix is secreted, im m ature bon e is form ed. Once the central portion of the m odel is ossified, it is referred to as th e “prim ary ossification center.” Further ossification of this prim ary ossification center can occur both enchondrally and in tram em branously. Keep in m in d th at bone form ed under th e prim itive periosteum does so in tram em bran ously, wh ereas th e bon e form ed at the ends is m ade enchondrally.

From the second through the sixth em bryonic m on th s, progressive ch an ges occur in th e tubular bon es. First, th e central (m edullary) can al cavitates, leaving a hollow tube of bon e with a large m ass of cartilage persistin g at each en d. With in th ese m asses of cartilage, th e secon dary ossification center, or epiphysis, will form . A cartilage plate persists between th e developin g m etaphysis an d epiphysis. Th is structure, th e physis, is respon sible for lon gitudin al growth of the long bone. On the other han d, the periosteum is prim arily respon sible for latitudin al growth , th ereby in creasin g girth .

Neuromuscular Development In th e secon d week of life, th e em bryo itself is bilam in ar, th at is, ectoderm an d en doderm . At th e caudal end of th e bilam in ar em bryo is an area referred to as th e “prim itive streak,” a cluster of cells that in vaginates between the two layers of th e bilam inar em bryo. The third layer subsequen tly form ed is referred to as th e “m esoderm .” This m esoderm is critical to the developm ent of th e bulk of th e m uscular and skeletal system s. It should be rem em bered th at th e n eural structures of th e cen tral n ervous system are ultim ately developed from cells originatin g from the ectoderm . Aroun d the third week, ectoderm al induction results in th e form ation of a n eural plate. Th e edges of th is plate curl dorsally to form a n eural tube (Fig. 1.6). Begin n in g in th e cen ter an d con tin uin g to each en d th is n eural tube will begin to close (Fig. 1.7). Obviously, failure to close cranially results in an en ceph aly, an d failure to close caudally results in spina bifida. A population of ectoderm al cells parallel to th e closed n eural tube, referred to as “n eural crest cells,” are the precursors of the dorsal root ganglia an d m uch of th e periph eral n ervous system . Most of th e n eural tube developm en t is guided by n otoch ordal in duction . Th e n otochord, which has been previously derived from the prim itive knob, a cellular aggregate of the bilam inar em bryo,

4


Neural plate

Neural fold

give rise to the m usculature of the th oracic and abdom inal cavities, as well as the rib cage (Fig. 1.8). The in tim ate proxim ity of th e m edial and interm ediate m esoderm clearly dem on strates why GU system an om alies are th e m ost com m on associated defects in con gen ital m usculoskeletal disease. Next in frequency are cardiac anom alies, own in g to th e fact th at th e h eart is also of m esoderm al origin . At about 4 weeks of em bryologic life, the paraxial m esoderm will segm ent into blocks of cells referred to as “som ites.” The som ites will n um ber between 42 and 44. Once th e som ites have segm ented, beginning cran ially and progressin g caudally over a 10-day period, th ey will furth er differen tiate in to th ree cell m asses—a derm atom e, a m yotom e, an d a sclerotom e, form in g skin , m uscle, an d skeleton respectively (Figs. 1.9 an d 1.10). The lim b buds will develop from progressive differen tiation of th ese som ites. As m en tion ed earlier, th e lim b buds are iden tifiable aroun d th e fifth week of em bryon ic life.

Development of Joints

Neural crest

Epidermis

Neural tube

Figure 1.6 Diagrammatic representation of neural tube forma-

tion. The ectoderm folds in at the most dorsal point, forming a neural tube that is connected by neural crest cells, and an outer epidermis. (Reprinted with permission from Gilbert SF. Developmental Biology. 3rd ed. Sunderland, MA: Sinauer Associates, 1991.)

has been cited to be the pacem aker of the neural tube. Th e m esoderm al plate parallels th e n otoch ord in its developm en t, th us elon gatin g at th e an terior en d first, with m ore caudal elem ents being added later.

Mesodermal Differentiation Two large m asses of m esoderm are seen on each side of th e n eural tube an d are th us referred to as “paraxial m esoderm .” Th ree distin ct areas in th is paraxial m esoderm have been identified: (1) m edial m esoderm ultim ately will form axial m usculature, (2) the in term ediate portion of the paraxial m esoderm in large part develops into the genitourin ary (GU) system , an d (3) th e lateral m esoderm will

Con den sations occur in the lim b bud wh ere m esenchym e aggregates. Ultim ately, th ese tubular condensations are separated by a discrete area referred to as the “interzone.” Th is in terzon e m arks th e prim itive join t an d typically h as three layers of cells—two parallel chondrogen ic layers an d a third interm ediate layer. The interm ediate zone of cells will ultim ately form th e syn ovium an d th e in tra-articular structures. Cavitation of this prim itive joint usually awaits con touring of the joint surfaces. It has been suggested that cavitation is prim arily an enzym atic process and is indepen den t of fetal m ovem en t. Th e join t spaces are typically well establish ed by th e 10th week of em bryon ic life. Classically, th e em bryo becom es a fetus by the 12th week. At that point all the em bryonic organ system s an d their respective organs h ave form ed. The rem ain ing 6 m onths of fetal developm ent is simply furth er growth an d m aturation of th ese previously form ed em bryologic structures.

THE GROWTH PLATE As previously stated, th e bones of the fetus are developing through the two m echan ism s of intram em branous and ench ondral bone form ation. Following birth, these processes con tinue at an accelerated pace. The periosteal surfaces of all long bones, as well as large portions of the flat bones, con tinue to grow as a result of intram em bran ous bone form ation. Bone is directly form ed in a collagenized m atrix by the activity of osteoblasts with out the ben efit of a cartilage m odel. Th e m ost critical m ech an ism in postn atal bon e m aturation is th e activity of th e physis or growth plate. Sign ifican t kn owledge curren tly exists as to th e an atomy an d


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Anterior neuropore closing

Anterior neuropore Central canal (containing amniotic fluid) Neural tube closed Ectoderm 1 Mesodermal somites 2

Neural groove Neural fold Notochord

A

Posterior neuropore open

Posterior neuropore

B

Figure 1.7 A: At the initial stages, both anterior and posterior neuropores are open. B: Closing of

the neural tube progresses both cranially and caudally. (Reprinted with permission from Gilbert SF. Developmental Biology. 3rd ed. Sunderland, MA: Sinauer Associates, 1991.)

physiology of th e n orm al growth plate, as well as its bioch em istry and its m echanical properties. This growth plate is a unique anatom ic structure. It is the essential m echan ism by wh ich m am m als are able to enlarge their en doskeleton . Wh ereas lesser an im als m ust m olt an exoskeleton in an effort to grow, th e physis allows for lon gitudin al growth of th e h igh er organ ism . It is clear, h owever, from the beginning that this unique anatom ic structure has its own obsolescen ce built in . Not on ly does it stop producin g bon e, but it is in large m easure con sum ed by its own product. Durin g th e tim e it exists, th e physis, for all its un ique an d critical importance, creates a m echan ical flaw in the

Migrating sclerotome cells

bon e. Th e growth plate is a critical en tity in postn atal bon e developm en t an d m aturation .

The Physis (Fig. 1.11) Th e ch aracteristic cytoarch itectural pattern of th e growth plate is typically presen t by th e fourth m on th of fetal life. For m ost lon g bones, the discoid configuration is typical. Th is is, of course, ch aracterized by a plan ar area of rapidly differen tiatin g cartilage, wh ich blen ds in to, but is n on eth eless structurally distin ct from , hyaline cartilage covering th e chon droepiphysis. Th is discoid physis is located between th e m etaphysis an d th e epiphysis of a lon g bon e.

Dermatome

Condensation of chondrocytes from sclerotome cells Myotome

Figure 1.8 Mesoderm formation

in human embryo. Transverse section through the trunk of an early 4-week embryo (A) and a late 4-week embryo (B). Sclerotome cells migrate from the somite, and these cells ultimately become chondrocytes. The remaining dermatome cells will form the dermis. The myotome cells will give rise to the striated muscles of the back and limbs. (Reprinted with permission from Gilbert SF. Developmental Biology. 3rd ed. Sunderland, MA: Sinauer Associates, 1991.)

Dorsal aorta Nephrotome of developing kidney

A

Somatic mesoderm layer

Splanchnic mesoderm layer

Intraembryonic coelom

Gut

Somatic mesoderm layer

B

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Gastrulation Rostrocaudal specification Segmentation

Somite

A

Dorsoventral specification Dorsal identity Ventral identity

B

Dorsoventral differentiation

Dermamyotome Sclerotome

C

Lateral sclerotome differentiation

Myotome Dermatome Anterior half Posterior half

D Medial sclerotome differentiation

Prospective neural arch

Prospective vertebral body

Prospective pedicle

Prospective intervertebral disc

Rib anlage

E Chondrification Ossification

The epiphysis is a secon dary ossification cen ter an d typically ossifies from a cen tral area, which th en grows centrifugally (Fig. 1.12). Th e epiphysis is n orm ally subjected to compressive forces. Con versely, an apophysis is also a sec-

Figure 1.9 The progressive dif-

ferentiation of the vertebral column. (Reprinted with permission from Thorogood P. Embryos, Genes and Birth Defects. New York, NY: John Wiley & Sons, 1997:282.)

on dary ossification cen ter, but on e th at ordin arily form s a poin t for m uscle attach m en t an d th erefore is subjected to ten sile forces. Both of th ese secon dary ossification cen ters typically sit astride a discoid physis.

Chapter 1: Basic Science Sclerotome

7

Notochord Sclerotome

Myotome

Myotome Intersegmental arteries

Plane of section B

Loosely arranged cells

Intersegmental artery

A

Aorta

Myotome

Notochord

Neural tube Condensation of sclerotome cells Plane of section D

B Densely packed mesenchymal cells

Nucleus pulposus Anulus fibrosus

Myotome Artery Nerve

C

Body of vertebra

D

Figure 1.10 A: Transverse section through a 4-week-old embryo. The top arrow shows the direc-

tion of growth of the neural tube and the side arrow shows the dorsolateral growth of the somite remnant. B: Coronal section of the same-stage embryo showing the condensation of sclerotomal cells around the notochord with loosely packed cells cranially and densely packed cells caudally. C: A transverse section through a 5-week-old embryo depicting the condensation of sclerotome cells around the notochord and neural tube. D: Coronal section illustrating the formation of the vertebral body cranial and caudal halves of adjacent sclerotomes resulting in the segmental arteries crossing the bodies of the vertebrae and the spinal nerves lying between the vertebrae. (Reprinted with permission from Moore KI, Persaus TVN. Before We Are Born. Essentials of Embryology and Birth Defects. 4th ed. Philadelphia, PA: WB Saunders, 1993:257.)

Th e growth plate h istologically can be sh own to h ave four distinctly separate zones: (1) resting, (2) proliferating, (3) hypertrophic (degeneration ), and (4) provision al calcification. Each zone has its own un ique anatomy as well as its own function. Type II collagen h as been dem onstrated to be the predom inant collagen in th e growth plate.

The Resting (Reserve) Zone Th is h istologic region is im m ediately subjacen t to th e bony epiphysis. Th e cells are roun dish an d occur in eith er sin glets or doublets. There is a high ratio of extracellular m atrix to cell volum e. Studies dem on strate a rath er abun dan t en doplasm ic reticulum , suggestin g active syn th etic activity. Blood vessels pass th rough this zon e with out sign ifican t perfusion resultin g in a decreased oxygen ten sion . Th e location an d histology of this region suggest th at it has the capacity to produce cartilaginous m atrix.

The Proliferating Zone Th e cells in th is region are typically flatten ed an d arran ged in longitudinal colum ns parallel to the long axis of th e

bon e. Again , a sign ifican t am oun t of en doplasm ic reticulum h as been dem on strated in th is region . Th e top cell in each of th e colum n s is th ough t to be th e germ in al cell for th e longitudin al growth of the colum n below. There is a high level of proteoglycan in this zone. Matrix vesicles are also presen t in h igh n um bers, suggestin g th eir role in m atrix m in eralization . O xygen ten sion levels are h igh est in this zone due to the rich vascular supply seen here. Considerin g th e anatomy an d biochem istry of this region , the m ajor fun ction s of th e proliferatin g zon e are cell proliferation an d m atrix production , both of wh ich are required for lin ear growth .

The Hypertrophic (Degeneration) Zone Th e cells iden tified in th is region are approxim ately five tim es the size of those in th e zones above. Intracellular m atrix gradually decreases in conten t as on e goes deeper into this zone. The longitudinal septa of intracellular m atrix persist into the deepest regions of the hypertrophic zon e. However, th in tran sverse septa becom e progressively m ore sparse, the deeper one goes into the plate. Sim ilarly,

8


Figure 1.11 Structure and blood supply of the growth plate. ([2011]. Used with permission of Elsevier. All rights reserved.)

glycogen, wh ich is identified in th e upper regions of the hypertroph ic zon e, is gradually lost in th e lower h alf. Th e concentration of lysosom al en zym es is extrem ely high, an d th e con cen tration of proteoglycan s an d hydroxyprolin e is m arkedly low. Electron m icroscopy reveals th e presen ce of an en doplasm ic reticulum in th e cells with in creased vacuolation, cytoplasm ic swelling, and increased num bers of m itochon dria and lysosom es th roughout th is region . In addition , th e previously n oted m atrix vesicles appear to be n ot on ly m ore prevalen t but also m ore active in th is region . It appears clear th at th e ultim ate fate of th e vessels in th is region is n ecrosis. Sim ilarly, th e relatively low levels of oxygen ten sion in dicate poor vascularity. All of th ese features—lysosom al en zym es, vacuolation , m argin al blood supply—support th e idea th at th e role of the hypertrophic zon e is to prepare the m atrix for calcification .

The Zone of Provisional Calcification Th e lowest region of th e growth plate is th e area wh ere calcification of th e cartilaginous m atrix occurs. It is h ere that the m atrix vesicle concentration is h ighest, and it is here that these vesicles are m ost active. The m echanism s for th e delivery an d liberation of th e calcium are still un der active investigation. It is felt that th e relative anoxia of this region plays a role in calcium release from the m itochon dria. Clearly, the function of this region is calcification. Typically, the m ineral is deposited only in the longitudinal bars of m atrix an d n ot in th e tran sverse septa.

The Metaphysis Any discussion of th e growth plate would not be com plete with out a word about th e subjacen t m etaphysis.


Figure 1.12 Early formation of the secondary ossification center

within the epiphyseal cartilage. The solid arrow indicates a wellvascularized cartilage canal with a branch into the hypertrophic cells, triggering the ossification process. (Reproduced with permission from Beaty JH, Kasser JR. Rockwood and Wilkins’ Fractures in Children. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Metaphyseal bone begins just distal to the last intact transverse septum . This specific region where the calcified cartilage becom es vascularized is referred to as “prim ary spon giosa bone” (Fig. 1.11). O steoblasts can be identified lining up on th e lon gitudin al bars of calcified cartilage. Assum in g this cartilage to be calcified, the process of ossification can begin spon tan eously. In certain m etabolic disease states, specifically rickets, in wh ich calcification has not occurred, ossification can n ot proceed n orm ally. As on e goes deeper in the m etaphysis, the calcified cartilage cores of the trabeculae will be seen to disappear. At th e poin t at wh ich n o calcified cartilage is present, the trabeculae are referred to as “secon dary spongiosa bone.” Th e functions of the m etaphysis are vascular in vasion , bon e form ation , an d bon e rem odelin g. In regard to bon e rem odelin g, resorption occurs on the internal surface of the cortical bone resulting in “cut back’’or funn elization of the end of the long bone. Th is m ech an ism is exactly th e opposite of wh at on e will see at the level of th e diaphysis. Fin ally, two periph eral structures surroun din g th e growth plate are n oteworthy. Th e first structure is th e ossification groove of Ranvier, wh ich is a wedge-sh aped rin g of cells surrounding the m argins of the plate at the level of the resting zone. This structure is felt to provide support an d allow for latitudin al growth of the physis. The second periph eral structure is th e perichondrial ring of La Croix. Th is is a fibrous sleeve that m erges with the periosteum and provides addition al m ech an ical support.

Blood Supply of the Growth Plate Essen tially, th e vasculature of th e plate can be subdivided into three m ajor groups: epiphyseal vessels, m etaphyseal vessels, and a sm all group of perichon dral vessels (Fig. 1.11). The epiphyseal vessel enters th e epiphysis an d term inally arborize in the upper portions of the proliferating

9

zon e. Th e en try poin t of th is vessel depen ds on th e am oun t of articular cartilage coverin g th e bony epiphysis. Ordin arily, th e vessel en ters th e bony epiphysis between th e articular m argin an d th e growth plate. In th e case of th e proxim al fem ur, th e vessel m ust travel beneath cartilage to the plate. Durin g its very tortuous course, it is extrem ely vuln erable to sh ear in jury. Th e m etaphyseal vessels term in ate in m any straigh t bran ch es, wh ich penetrate th e lowest regions of the growth plate. It is their presence that in som e m easure participates in th e calcification of th e m atrix. Th e perich on dral vessels supply th e periph eral cells an d do n ot en ter th e depth s of th e epiphysis. As previously n oted, th e proliferatin g zon e is th e on ly area receivin g a blood supply. Th e rem ain der of th e plate is largely avascular. Nutrition an d oxygen for cell m etabolism are obtained by diffusion.

Patterns of Growth Characteristically, long bon e growth is gen erally considered to be a lon gitudin al ph en om en on . Th e an atom y of th e previously described physis clearly em ph asizes its lin ear orien tation an d its predisposition to grow in th is fash ion . However, som e latitudin al growth is essential for norm al plate developm en t. Th is growth is accom plish ed both by interstitial growth within the plate and appositional growth at the periphery in the region of the groove of Ranvier. Latitudin al expansion of the physis will obviously be precluded in areas th at are juxtaposed to the subch ondral plate once th e subch on dral plate h as developed. Th ere are a n um ber of region al variation s in plate growth . Most of th e tim e th ese variation s result from m echanical lim itation to interstitial expansion. As m entioned earlier, th e subch on dral plate is on e of th e m ajor m ech an ical factors lim itin g plate growth. Differential growth of th e various ossification cen ters is also typical. Th e distal h um erus is a good example of such differen tial growth. Th e troch lea an d capitellum are in itially equal in size. Th e ossification cen ter of th e capitellum ten ds to develop earlier and m ore rapidly, and in doing so, it restricts its own interstitial expan sion . The trochlea does n ot appear until later and therefore can ultim ately achieve a larger size because it h as a longer period of in terstitial growth . Ultim ately, when both of th ese cen ters fuse, latitudin al growth of th e distal h um erus becom es a periph eral fun ction at th e level of the epicon dyles.

Control of the Growth Plate As on e would expect, a n um ber of factors affect n orm al plate growth an d developm en t. Both local an d system ic factors have been clearly identified as m anipulating the plate and the way in which growth is accomplished. Th e Heulter-Volkm an n law is an importan t local factor. Increasing compression forces across the physis will slow lon gitudin al growth . Conversely, in creasing tension on th e physis will result in increased longitudinal growth (Delpach law). Th is prin ciple h elps to explain th e

10


progression on an gular deform ities of th e lower extrem ities. Th e in tegrity of th e periosteum acts as an oth er m ech an ical restrain t on th e plate. Because it attach es directly to the perichondral ring of Lacroix, it will control the am oun t of latitudin al an d lon gitudin al growth seen . O bviously, th e vascular supply to th e plate is critical for growth in tegrity. Any disruption or dam age to th is supply of th e plate will clearly im pede its ability to fun ction an d grow n orm ally. A n um ber of system ic factors h ave also been implicated in n orm al plate fun ction . Gen etic as well as n utrition al factors certain ly play a role in physeal m an ipulation . However, m ost in dication s are th at h orm on al con trol is th e prim ary regulator of plate fun ction . Growth horm one is a peptide h orm one produced by the pituitary glan d th at stim ulates physis activity by affectin g cellular proliferation via its m ediators, som atom edin s an d sulfation factor. Excessive levels of th is h orm on e will cause an anticipated growth plate widening and ultim ately gigan tism . Sh ould th e plate be closed at th e tim e of excessive growth stim ulation, acrom egaly results. Th is condition is typified by in creased apposition al bon e growth . O n th e oth er h an d, deficien cy of th is h orm on e typically slows th e plate growth . However, because th e plate ten ds to rem ain open lon ger, th e ultim ate h eigh t is variable. Th is fin din g suggests th at growth horm one h as no effect on plate closure, but rather a regulatory effect on the rate of proliferation an d osteogen esis. Thyroid h orm one has a prim arily troph ic effect on cartilage growth an d is essential to the norm al health an d growth of cartilage. Recen tly, a syn ergistic effect with in sulin -like growth factor h as been suggested. Excess levels of thyroid h orm on e h ave wide-ran gin g system ic effects but relatively few m usculoskeletal m an ifestation s. Low levels of thyroid h orm on e, h owever, result in growth retardation , erosion of th e ch on droepiphysis, an d degradation of m ucopolysacch arides. Glucocorticoids are steroid horm ones produced by th e adren al cortex an d sim ilarly seem to exert a troph ic effect on cartilage. A physiologic level is required for n orm al physeal function. In the face of excessive levels, derived either en dogen ously or exogen ously, th ere is a stun tin g effect on the ch ondrocytes with decrease in m itotic and synthetic activity. In adequate levels of adren al steroids can also result in stun tin g, but to a lesser degree. Sex h orm on es, an drogen s an d estrogen s both , are steroid h orm ones. The androgens are felt to exert their effect in th e hypertroph ic zon e. Testosteron e seem s to stim ulate rapid cell division, calcification, and prem ature physeal closure. Con versely, deficiency states of androgenic h orm on es are ch aracterized by a m arked delay in physeal closure, resultin g in the typical eunuchoid body h abitus. Estrogen , on th e oth er h an d, apparen tly h as a m ore com plex effect on th e plate. Som e suppressive activity on plate fun ction has been dem on strated with excessive levels of estrogen activity.

Plate Closure Physiologic closure of th e growth plate is a com plex ph en om en on. Clearly, there are h orm on al as well as local factors th at m an ipulate th is process. On ce physeal growth h as stopped, initial closure of the plate begins. The portion of the plate that closes first and the pattern of closure vary from bone to bon e. Ultim ately the growth plate, as we kn ow it, disappears, and the m etaphysis fuses to the secondary ossification cen ter. Fem ales close th eir physes earlier th an m ales, probably due to estrogen s, wh ich accelerate cartilage replacem en t an d osseous m aturation . In any event, the process begins with th e form ation of an ossified bridge between th e epiph ysis and the m etaphysis. It ends with a complete disappearan ce of the cartilaginous physis. As m entioned previously, the location of the initial bridge in the transverse plane of the plate varies from bone to bone.

Biomechanics of the Growth Plate Th e cartilagin ous physis is clearly a m ech an ical defect at th e en d of a lon g bon e. It is vuln erable n ot on ly to a n um ber of ch em ical an d toxic effects but to m ech an ical disruption as well. As with all biologic tissues, injury to the plate can occur wh en th e load exceeds th e ultim ate ten sile stren gth . At that point, failure will occur. The result will be a function of th e stren gth of th e plate, as well as th e m agn itude of th e load applied. Th e cross-section al an atomy of a physis varies from bon e to bon e. Som e plates are relatively plan ar with few m etaphyseal in terdigitation s. Oth ers are con toured to a sign ificant degree, m aking failure pattern s m ore complex. These interdigitations, referred to as “m am m illary processes,” con fer a certain resistance to sh ear forces. Un fortunately, the greater constraint con ferred by these processes, the greater th e risk of prem ature physeal closure sh ould th e plate fail in sh ear resultin g in m am illary process fracture. Such is th e case of th e distal fem oral physis; fractures disrupt th e m am m illary processes, frequently resulting in prem ature physeal closure. As a gen eralization, it is fair to say that the plate is m ost vulnerable when it is actively growing. Therefore, in the prepubertal and pubertal individuals, on e would an ticipate th e plate to be m ost susceptible to excessive m ech an ical load. Plate failure an d its lon g-term complications can be relatively wide ran ging and is further explored in th e ch apter on pediatric traum a.

RECOMMENDED READINGS Ballock RT, O’Keefe RJ. Current con cepts review: th e biology of th e growth plate. JBJS Am 2003;85-A:715 –726. Day TF, Yang Y. Wnt and hedgehog signaling pathways in bone developm ent. JBJS Am 2008;90:19 –24. Dietz FR, Math ews KD. Current concepts review: update of the gen etic bases of disorders with orthopaedic m anifestation s. JBJS Am 1996;78-A:1583 –1598.


Sectio n 2

11

Basic Science o f Cartilage and Bo ne John A. Zavala

John N. Delahay

INTRODUCTION Cartilage and bon e are th e basic buildin g blocks of th e m usculoskeletal system . This ch apter describes the cellular composition , m icroscopic structure, and basic physiology of th ese im portan t tissues.

CARTILAGE Cartilage is a specialized, fibrous con nective tissue. Its function varies on the basis of its histologic type. Th ere are essen tially th ree h istologic types of cartilage. In addition , the growth apparatus of the skeleton includes physeal and epiphyseal cartilage, wh ich are varian ts of th ese basic subtypes. Table 1.1 shows th e composition of the various types of cartilage.

Types of Cartilage Hyaline cartilage: This tissue covers the ends of lon g bon es, form in g th eir articular surfaces. Hyalin e cartilage is importan t for its ability to resist compressive forces and provide a relatively frictionless surface for sm ooth joint m otion . Fibrocartilage: The m atrix of fibrocartilage is h igh in collagen fibers. Th ese fibers ten d to be visible by ligh t m icroscopy. Th e m en isci, th e an n ulus fibrosus, an d the symphysis pubis are largely fibrocartilage. Biom ech an ically, fibrocartilage is design ed to resist ten sile load. Elastic cartilage: Elastic cartilage is composed prim arily of elastic fibers. It is foun d in th e extern al ear, th e epiglottis, an d th e tip of th e n ose. Elastic cartilage has a m oderate ability to resist tensile load, but it also allows for som e con trolled deform ation .

Articular Cartilage From an orth opaedic stan dpoin t, th e m ost im portan t h istologic type of cartilage is hyalin e cartilage. It is a very tough , resilien t, firm m aterial th at allows for alm ost friction less m otion of the joints. The average thickness of th e articular surface is between 2 an d 4 m m , with som e surfaces bein g as thick as 7 m m . Norm al adult hum an articular cartilage is typically described as being divided in to four histologic zon es (Fig. 1.13).

Histologic Zones Tangential (Gliding) Zone Th e tan gen tial zon e is th e m ost superficial zon e of flatten ed cells. Collagen fibers are arran ged parallel to th e join t surface an d h elp lim it sh ear forces. Transitional (Intermediate) Zone Th e cells in th is zon e are roun d or ovoid an d are ran dom ly distributed th rough out th e m atrix in th is region . Th ese cells m anifest sm all m em brane processes, which are noted to exten d in to th e m atrix. Th ere is a h igh er level of m etabolic activity in this zone. Radial Zone Th e cells in th is zon e are arran ged perpen dicular to th e articular surface. Mem brane processes are sim ilarly noted in this region and interconnect th e cells. In addition, glycogen -contain ing storage granules can be foun d in these cells. Th is zon e con tain s th e h igh est con ten t of proteoglycan s an d th e lowest con ten t of water. Calcified Zone Sm all irregular cells with pyknotic nuclei are found in lacun ae surrounded by h uge am oun ts of hydroxyapatite crystal. Tidemark Th is is a wavy basoph ilic lin e th at appears wh en th e growth plate closes. Th is lin e is seen to be in terposed between th e radial zon e an d th e calcified zon e. No blood vessels can be seen to cross this line in norm al articular cartilage. Lamina Splendens Th is surface layer con sists of tigh tly packed collagen bun dles tan gen tial to th e surface an d sligh tly subjacen t to it. It is felt th at th is m aterial causes surface un dulation s seen in articular cartilage and represen ts part of the complex lubricating system .

Morphology and Physiology Th e cells th at are in tegral to th e articular surface are called “chon drocytes.” Th ey accoun t for on ly 0.1% of th e volum e of th e tissue. Th e sh ape of ch on drocytes varies depen din g on th e zon e in wh ich th ey are foun d. Typically, th e n ucleus is located in th e lacunae of articular cartilage and is eccentric and basophilically stain ed. Num erous organelles such as a Golgi complex, endoplasm ic reticulum , m itochon dria, an d vacuoles h ave all been iden tified in th ese cells. Articular tissue is isolated in th at it does n ot h ave a n eural, lymphatic, or vascular supply.

12


TABLE 1.1

APPROXIMATE COMPOSITION OF THE VARIOUS TYPES OF CARTILAGE Solids (%) Cartilage Articular Epiphyseal Fibrocartilage Elastic

Water (%)

Collagen (%)

GAG

Elastin

Other

72 81 74 71

66 37 78 53

18 15 2 12

— — 0.6 19

16 48 19 16

Includes monocollagen proteins, calcium phosphorous, other ions, and macromolecules such as DNA and RNA. Reprinted with permission from Wiesel SW, Delahay JN. Principles of Orthopaedic Medicine and Surgery. Philadelphia, PA: Saunders; 2001.

The chem istry of articular cartilage is essentially th e ch em istry of its m atrix (Table 1.2). As n oted, th e ch on drocytes are distributed in th e cartilage m atrix. Th is m atrix prim arily is composed of water, accoun tin g for 65% to 80% of th e wet weigh t of cartilage. Approxim ately 10% to 20% of th e wet weigh t of cartilage m atrix is collagen an d approxim ately 5% to 7% is a unique proteoglycan com m only referred to as “aggrecan.” In addition, electrolytes are present in this fluid. Collagen con stitutes 10% to 20% of th e m atrix wh en wet an d approxim ately 50% to 60% wh en dry. Type II collagen account for 90% to 95% of collagen seen in articular cartilage. In the superficial layer, collagen fibers are arranged parallel to th e join t surface, wh ereas in oth er layers, th ey are uniform ly distributed. Th e collagen m esh work gives cartilage its ten sile stren gth an d form an d m ain tains th e location of th e ch on drocytes. Each tropocollagen m olecule is composed of three alpha-1 chains.

Th e th ird m atrix con stituen t is a complex proteoglycan m acrom olecule, referred to as “aggrecan” (Fig. 1.14). Th is m olecule con sists of a large protein core to which are attach ed upwards of 100 ch on droitin sulfate m olecules an d 40 to 50 keratan sulfate ch ain s. Th ese substan ces are polysacch aride m olecules an d are un ique to articular cartilage. The polysaccharide m olecules, specifically the ch on droitin an d keratin sulfate, are attach ed rough ly perpen dicular to th e protein core, wh ich , in turn , is attach ed to a cen tral filam en tous core of hyaluron ic acid via a lin k protein . Th e distribution of th e aggrecan m olecules is n ot h om ogen eous. Th e h igh est con cen tration s of th ese m olecules can be foun d in the perilacunar areas, whereas their concentrations seem to be less in the superficial zones. Sim ilarly, based on th e age, th e location , an d th e disease state, there is a variation in the am oun t of chondroitin-4-sulfate, ch on droitin -6-sulfate, an d keratan sulfate. Th e im portan ce, h owever, of these m acrom olecules rem ains unquestioned.

B

A Figure 1.13 Cartilage morphology: (A) superficial layer collagen stains red with eosin; intermediate layer proteoglycan stains bluish with hematoxylin. The basal layer with increasing collagen, binding the cartilage to the bone and stains predominantly red with eosin. The subchondral bone below, primarily collagen and mineral, stains densely red. (B) Diagram on right outlines the corresponding zones and cellular morphology. (Reprinted with permission from Damron T. Orthopaedic Surgery Essentials. Oncology and Basic Science. Philadelphia, PA: Lippincott Williams & Wilkins, 2008.)


TABLE 1.2

ADULT ARTICULAR CARTILAGE COMPOSITION Component

Cartilage Content (%)

Cells

95

Matrix Water Mineral Organic Collagen Proteoglycan Protein

5 70 — 30 60 25 15

Reprinted with permission from Damron TA, Morris CD, Tornetta P, Einhorn TA. Oncology and Basic Science. Philadelphia, PA: Lippincott Williams & Wilkins; 2007.

Th ey create h uge electron egative fields aroun d th em . Th ese large electrostatic dom ains bestow upon articular cartilage its biom echanical resiliency and resistance to deform ity. Th e ability to hydrate th e m atrix largely depen ds on th e con centrations of these large m acrom olecules. Because cartilage is an avascular m aterial, its n utrition depen ds on diffusion . Adult articular cartilage essen tially m ust depend on diffusion from synovial fluid through the surface layers to provide cartilage n utrition. O bviously, the rates of diffusion are a fun ction of th e size of th e m olecule an d the concentration gradient. Perm eability is slower in the deeper layers because of the greater fixed charge. As th is fixed ch arge decreases, as in th e case of osteoarth ritis an d oth er disease states, perm eability rates ten d to in crease.

Aggrecan (CS/KS)

Link protein

13

As on e would expect, given its relative avascularity, th e m etabolism of articular cartilage is prim arily an aerobic. Although there are a few aerobic pathways, they are far less developed an d of relative little importan ce. Articular cartilage, wh ich was on ce though t to be m etabolically inert, h as clearly been sh own to be quite th e opposite. Th e ch on drocytes are capable of syn th esizin g protein , specifically collagen , usin g stan dard path ways of DNA/RNA tran scription . In addition , th ey can syn th esize th e glycosam in oglycan (aggrecan ) component of th e m atrix. Most studies h ave in dicated that synthetic rates are linear with tim e. Alth ough quite rapid in th e im m ature, in th e adult the rates are relatively constant, despite aging. Turn over does exist in the articular surface and the m atrix. Wh ile m itotic activity is seen in th e im m ature an im al, this gen erally ceases on ce m aturation is achieved. While there is generally no m itotic activity seen in norm al adult articular cartilage, un der certain circum stan ces ch on drocytes can becom e active as chondroblasts. Th e con tin ued ability of cartilage to with stan d sh ear, compression, and tensile forces depends on th e composition of th e extracellular m atrix. Main ten an ce of th is m atrix requires ch on drocyte-m ediated syn th esis, assem bly, an d degradation of proteoglycan s, collagen s, an d oth er m atrix m olecules. Cartilage en zym es are felt to be at th e h eart of this rem odeling system . Proteolytic enzym es (proteinases) that are synthesized by th e chondrocytes appear to be key in th e degradation of articular cartilage. Two m ajor groups of protein ases are curren tly receivin g atten tion : m etalloprotein ases, such as collagen ase an d gelatin ase, an d th e cath epsins. Collagen ase is key to the breakdown of the

HA

Decorin (DS)

Lumican (KS) or Fibromodulin (KS)

Biglycan (DS) Figure 1.14 Cartilage proteoglycans. Aggrecan is the major aggregating proteoglycan (25% of dry weight): it is associated with compression and linked to hyaluronic acid (HA). The other proteoglycans are nonaggregating and associate with and stabilize fibrils. (Reprinted with permission from Damron T. Orthopaedic Surgery Essentials. Oncology and Basic Science. Philadelphia, PA: Lippincott Williams & Wilkins, 2008.)

14


H2 O

n o lon ger reproduce. There is an overall decrease in the glycosam inoglycans an d a relative increase in the protein con ten t of th e articular surface. As th e aggrecan com pon en t of articular cartilage m atrix decreases, th e overall water con ten t decreases. With loss of water an d proteoglycan , th e cartilage becom es stiffer an d less pliable.

Figure 1.15 Resistance to compression: on the left, articular

Trauma to the Articular Surface Mechan ical injury, such as superficial and deep laceration , is not uncom m on. Th e healing of these chon dral defects, h owever, varies depen din g on wh eth er or n ot th e subchondral plate is violated. Superficial laceration th at does n ot cross th e tidem ark will cause ch on drocyte proliferation but little h ealing due to avascularity. With a deep laceration, on e will ordin arily see a vascular respon se an d resultan t adherent fibrous plaque form s. This becom es populated with proliferatin g fibroblasts, an d over a period of 2 to 6 m onths, healing with fibrocartilage occurs. This fibrocartilage provides articular surface continuity but is biom echanically less efficient than the n orm al hyaline surface. Un fortunately, m any of these new fibrocartilage plaques are quite vulnerable. Ch em ical dam age to th e articular surface is gen erally th e result of deposition of m etabolic en d products an d can be seen in gout, pseudogout, och ron osis, an d h em ach rom atosis. The deposition of these end products in th e articular cartilage layer alters the norm al cartilage m atrix, typically resulting in increased stiffn ess. As a result, shear and impact load injury m ay occur, dam aging the articular surface.

Synovial fluid Compression

Bone Requirements:

• High aggrecan content • High GAG-SO4 content • Aggregate formation

cartilage is in equilibrium, with the swelling pressure of the proteoglycan balanced by the tensile force in the collagen fibril. With compression, water is squeezed out of the cartilage and a new equilibrium is reached, with an increased swelling pressure of the proteoglycan balancing the applied compression. When the compression is removed, water is drawn in and the former steady state is achieved. (Reprinted with permission from Damron T. Orthopaedic Surgery Essentials. Oncology and Basic Science. Philadelphia, PA: Lippincott Williams & Wilkins, 2008.)

protein collagen . Cath epsin s are critical for th e degradation of aggrecan . Cartilage as a tissue serves a favorable biom ech an ical role. It is an am azin gly in den table tissue. Th is property is a fun ction of its hyperhydrated state, wh ich allows it to return to its origin al sh ape wh en in den ted (Fig. 1.15). Th e ability of cartilage to deform over tim e, or “creep,” is a function of the thickn ess of the articular surface. Cartilage is also able to provide th e diarth rodial join t with a certain level of sh ock absorption . Th is ability can occur passively, as a result of cartilage’s deform ation on impact, an d actively, as a fun ction of join t m otion an d m uscle len gth en in g. Join t con gruen ce, especially with loadin g, depen ds on the cartilage thickness and its pliability. Th ere is an inverse relation sh ip between cartilage th ickn ess an d join t con gruen ce. Specifically, th e th icker th e articular surface, such as the patellofem oral joint, the less congruent th e joint will be. As th e articular surface becom es dam aged from various path ologic states, th e ability of th is cartilage to fun ction norm ally in its biom echan ical m odes is m arkedly altered. Th is ch an ge simply compoun ds th e rate of join t breakdown in a n um ber of differen t path ologic situation s.

Pathologic Changes Aging Th e ch on drocytes in th e agin g articular surface ten d to in crease in size, in crease their content of lytic en zym es, and

Osteoarthritis Both biom echan ical an d bioch em ical m ech an ism s are seen in the degradation of cartilage leadin g to osteoarthritis. Three overlapping stages can be seen: cartilage m atrix dam age, ch on drocyte respon se to tissue dam age, an d th e declin e of th e ch on drocyte syn th etic respon se an d progressive loss of tissue. With th e disruption of th e m atrix, th ere is a con com itan t increase in the water content. There is a decrease in proteoglycan aggregation and aggrecan concen tration. Decreases in length of glycosam inoglycan chain s are also seen. Th e collagen con ten t ten ds to rem ain relatively con stan t. Th ere are generally som e distribution changes of collagen between the various layers. Chondrocytes detect tissue dam age and release m ediators th at result in both anabolic an d catabolic alteration s in cartilage m etabolism . Early, th ere is an increased rate of DNA synthesis and cell replication. Th ere is an in creased rate of protein an d glycosam in oglycan syn th esis. Ultim ately, th e en tire reparative effort fails, and at this point, water content, glycosam in oglycan conten t, an d, to a lesser degree, collagen con ten t gradually decrease. As th ese ch an ges occur, th e m ech an ical properties of th e articular surface suffer an d m ech an ical failure of th e cartilage is im m in en t (Fig. 1.16).

15


Fissures

Safranin O staining change

Fibrillation

Cartilage loss

Tidemark Subchondral A bony end plate

Calcified cartilage

B

Figure 1.16 (A): Low-power magnification of a section of a glenohumeral head of osteoarthritic

cartilage removed at surgery. (B) A high-power magnification of surface fibrillation showing the vertical cleft formation and widespread large, necrotic regions of the tissue devoid of cells. (Reprinted with permission from Buckwalter JA, Einhorn TA, Simon SR. Orthopaedic Basic Science: Biology and Biomechanics of the Musculoskeletal System. 2nd ed. Rosemont, IL: American Academy of Orthopaedic Surgeons, 2000.)

BONE Bone is a connective tissue that serves m ajor roles as a structural support for the m usculoskeletal system an d as a dyn am ic reservoir for calcium . Th is latter fun ction is essen tial in the m aintenan ce of n orm al skeletal h om eostasis as well as calcium an d phosph ate m etabolism . Bon e is in a constant state of flux between con tinual bon e form ation and bone resorption; the processes are norm ally finely balan ced. Th e balan ce between resorption an d form ation is con trolled by a n um ber of local and system ic factors. The alteration in any of th ese system s will clearly affect the way in which the norm al bone turnover is regulated.

Bone Morphology and Physiology Bone is a connective tissue, as is cartilage, ligam ent, and tendon . It is un ique, h owever, in th at its extracellular m atrix becom es im pregn ated with a m in eral. O n a m acroscopic level, bone is typically described as being cortical or cancellous. Cortical (compact) bone is th e bon e typically found in the diaphysis of long bones as well as in subchondral plates, th e outer an d in n er table of th e skull, an d th e outer an d inner table of the pelvis. Cancellous (trabecular) bon e is m ore typically seen in areas such as the m etaphysis of a lon g bon e an d th e diploic space of th e skull. Can cellous bon e is extrem ely respon sive to m ech an ically applied stress an d is prim arily affected by Wolfe’s law. Simply stated, this law emphasizes the observed fact that bone will be form ed in areas where it is needed and will be resorbed in areas wh ere it is n ot n eeded. Microscopically, th ere are two levels of organ ization . Norm al bon e is lam ellar an d can be eith er cortical or can cellous. Lam ellar bone has a h igh ly ordered arrangem ent of collagen and cells. The differentiation is determ ined on th e basis of th e distribution of th e collagen fibers in th e m atrix as well as the orientation of the cells. Im m ature bone is referred to as “woven bon e” in wh ich the collagen fibers are

ran dom ly and loosely arranged. The cells are large and irregular an d are located in very rudim en tary lacun ae. Wh ile com m only seen in the fetus an d prepubertal child, after growth completion, woven or im m ature bone is not seen except in th e presen ce of path ologic states. In th ese situation s, th e presen ce of woven bon e in dicates h igh rates of bon e turn over. In th e adult skeleton , all th e bon e presen t is lam ellar bon e. In can cellous bon e, th e lam ellar bon e is con figured in a very loose h on eycom b with few blood vessels en terin g the bone surface of the trabeculae. Cortical bone (haversian bon e), on th e oth er hand, is a very h ighly ordered, geom etrically arranged structure. The basic unit of cortical bon e is th e osteon or Haversian system th at is built aroun d a cen tral capillary can al. Th is can al is surroun ded by layers of m in eralized bon e m atrix. Th e m atrix collagen in each successive layer has a different orientation (Fig. 1.17), givin g th e bon e “ply stren gth .” Th e osteocytes are located in lacun ae, an d th e cellular processes radiate from th e lacun ae in sm all ch an n els called “can aliculi” (Fig. 1.18).

Figure 1.17 Diaphyseal cortex of a long bone. (Reprinted with

permission from Gamble JG. The Muscoloskeletal System: Physiologic Basics. New York, NY: Raven Press, 1988.)

16

Orthopaedic Surgery: Principles of Diagnosis and Treatment Epiphyseal line Trabecular bone

Epiphysis Cartilage

Trabecular Bone Medullary (marrow) cavity

Trabeculae Osteoclast

Osteoblasts Osteocytes

Cortical (compact) bone Capillaries in haversian and Volkmann's canals Concentric lamellae

Periosteum Capillaries in haversian canals

Capillary in Volkmann's Canal

Interstitial lamellae

Osteocyte Circumferential subperiosteal lamellae

In any given section of haversian bon e, th ere are m ultiple osteon al system s. Between osteon al system s, th ere is additional lam ellar bone filing the void. These lam ellae are referred to as “interstitial lam ellae.” In addition, surroun din g th e wh ole cortex itself is a layer of lam ellar bon e, referred to as th e “outer circum feren tial lam ellae.”

Bone Circulation Bone has a vascular flow accoun ting for 8% of th e cardiac output in th e n orm al restin g state. Most of th e cells in adult bon e are with in 0.1 m m of a sm all blood vessel. O n a m acroscopic level, th e blood vessel en ters th e bon e typically th rough th e n utrien t foram en (Fig. 1.19). O n ce in teriorized, th e blood vessels arborize exten sively th rough the m edullary canal an d periphery to the periosteum . In addition , blood vessels supplyin g th e periosteum arborize over th e surface of th e bon e. Th e n utrien t artery system is a h igh -pressure system , wh ereas th e periosteal system is a low-pressure system with resultant centrifugal flow. Th is reverses in th e settin g of disruption of th e en dosteal system . Periosteal blood supply is adequate to feed th e outer third of th e cortex, whereas the in terosseous or m edullary supply carries the in n er two-thirds of the cortex.

Bone Cells Bone cells have th e usual cellular structure and cellular organ elles. In bon e, th ere are several differen t cell lin es. O n e

Figure 1.18 Schematic diagram

of cortical and trabecular bone showing the different microstructures. (Reprinted with permission from Hayes WC. Biomechanics of cortical and trabecular bone: implications for assessment of fracture risk. In: Mow VC, Hayes WC, eds. Basic Orthopaedic Biomechanics. New York, NY: Raven Press, 1991.)

rudim entary population of progenitor cells is capable of differen tiatin g in to an osteoblastic lin e, an d th e oth er is capable of differen tiatin g in to an osteoclastic lin e. Th e basic bon e-form in g cell or osteoblast (Fig. 1.20) m easures approxim ately 20 to 30 µ m in diam eter. Th e cell h as a sin gle n ucleus and basoph ilic cytoplasm an d is usually polyhedral in sh ape. Typically, th ese cells are foun d in layers lin ed up on th e surface of bony trabeculae. Th ey con tain m ore en doplasm ic reticulum , Golgi apparatus, an d m itoch on dria given th eir fun ction of m atrix production . In itially, th e organ ic m atrix (osteoid) th ey lay down is un m in eralized. Matrix is m ade at the rate of 1 µ m / day and takes about 15 days to ossify. Th erefore, th e n orm al width of osteoid on th e surface of any given trabecula rem ain in g un m in eralized is approxim ately 15 µ m . As th e osteoid is form ed by th e osteoblast, th e cells becom e in corporated in to th e m atrix at regular intervals. The area of incorporation is referred to as a “lacun a,” and the osteoblast having buried itself in a lacuna becom es known as an “osteocyte.” Th e osteocytes vary in sh ape an d size on th e basis of th eir age. Th ese cells h ave a h igh n ucleus-to-cytoplasm ratio with n um erous cellular processes exten din g in to th e can alicular system . Th ese cellular processes are critical for m ineral exchange and the m aintenance of calcium hom eostasis. Th e can alicular system ultim ately lin ks th e cellular processes of th e osteocyte with the vascular channel in the central canal of th e osteonal system . In addition to their role in the m aintenance of skeletal hom eostasis and calcium m etabolism , the osteocytes have been shown

17

Chapter 1: Basic Science Periosteal arteriole and vena comitans

Attached muscle

Periosteal capillaries

Interfascicular venules Cortical capillaries Endosteal capillaries Medullary sinusoids

Medullary artery

Central venous sinus

Articular cartilage End-arterial terminals Metaphyseal arteries and terminals of the medullary arterial system

Venous sinusoids and metaphyseal veins

Principal nutrient artery and vein

Figure 1.19 Blood supply of a long bone. Three basic

Medullary sinusoids

Periosteal capillaries in continuity with cortical capillaries

blood supplies are shown: (1) nutrient; (2) metaphyseal, which anastomoses with epiphyseal after epiphyseal closure; and (3) periosteal. The numerous metaphyseal arteries arise from periarticular networks and anastomose with terminal branches of ascending and descending medullary arteries. Periosteal capillaries emerge from the cortex (efferent blood flow). (4) A periosteal arteriole feeds capillaries that provide afferent blood flow to a limited outer layer of cortex. (Adapted from Rhinelander FW. Circulation of bone. In: Bourne GH, ed. The Biochemistry and Physiology of Bone. 2nd ed. New York, NY: Academic Press, 1972.)

to be capable of a lim ited am oun t of bon e resorption . Th is ph en om en on is referred to as “osteocytic osteolysis.” However, this lim ited am ount of resorption is felt to be im portan t in th e physiologic m ain ten an ce of skeletal m ass. Th e osteoclast is a large, m ultin ucleated cell con tain in g num erous m itoch on dria an d very den se gran ules. Of significance is th e presence of an unusual ruffled border of the active surface of these cells. This ruffled border appears to be th e “active en d” of th e osteoclast wh ere th ere are n um erous chan nels an d vesicles present (Fig. 1.21). The m ajor function of the osteoclast is to resorb bone. They synthesize tartrate-resistan t acid phosph atase. Based on its size, the osteoclast is far m ore efficient th an the osteoblast. It is capable of undoing the work of 20 osteoblasts. The n uclear ratio (osteoclast-to-osteoblast ratio) is 6:1. Th e osteoblast an d osteoclast work in tan dem . Th ere is always a population of both cell lines active in the skeleton . Measurable levels of bon e resorption and form ation are ongoing. When bone resorption ceases and bone form ation begin s, th is even t is m arked by th e form ation of a “cem en t”

Interfascicular veins and capillaries in muscle Central venous channel Large emissary vein V Tr ansverse epiphyseal venous channel V V V

V V V

or reversal lin e. Th is h istologic m ark em ph asizes th e con tin uously reciprocatin g bon e-form in g an d bon e-resorbin g activity essen tial for n orm al skeletal h om eostasis. Th e average cem ent line is approxim ately 1 µ m in width . It is easily stain ed with th e usual tech n iques because of its bioch em ical differen ces with th e surroun din g m atrix.

Bone Matrix and Formation Bon e is a unique m aterial in th at it is biph asic. It is a com posite structure, com bin in g a blen d of m in eral in m atrix. Th e m in eral ph ase, accoun tin g for 70% of bon e by weigh t, is prim arily calcium hydroxyapatite. The organic ph ase, or m atrix, constitutes approxim ately 30% of bone by weight. Th is organ ic m atrix is composed prim arily of collagen , accoun tin g for 95% of its weigh t. Th erefore, like cartilage, collagen is an im portan t compon en t of th e tissue m atrix. In addition to collagen , sm all am oun ts of m ucoprotein , ph osph olipid, an d sialoprotein s are presen t. Alon g with th ese ch em ical compon en ts, 2% by weigh t is water an d th e cells accoun t for an addition al 2% (Table 1.3).

18


Figure 1.20 Light (A) and elec-

A

Bon e collagen, which is predom inantly type I, beh aves differen tly from collagen in soft tissue. It is on ly sparin gly soluble. It has a lower sh rinkage temperature, and it does not denature. The tropocollagen m olecules overlap each other by 25% of len gth or quarter staggers. In addition , there are sm all pores, or “hole zones,” which exist between the sides of adjacen t parallel m olecules. Th e net effect of the quarter stagger an d “hole zones” is to m ake it m ore accessible for the deposition of m ineral. These properties are th e result of the un ique cross-linking.

B

tron (B) photomicrographs of osteoblasts. (Reprinted with permission from Buckwalter JA, Einhorn TA, Simon SR. Orthopaedic Basic Science: Biology and Biomechanics of the Musculoskeletal System. 2nd ed. Rosemont, IL: American Academy of Orthopaedic Surgeons, 2000.)

Th ere are n um erous types of collagen , all of wh ich preserve its ch aracteristic triple h elical structure. Th ose m ost importan t to th e m usculoskeletal system are type I collagen, wh ich is seen in bon e, skin , ten don , an d blood vessel wall, and type II collagen, which is seen in articular cartilage an d th e n ucleus pulposus. In vestigation s in to collagen polym orph ism an d th e m olecular bases are actively ongoing. Num erous collagen dysplastic diseases, as well as th eir gen etic defects, con tin ue to be elucidated (Table 1.4).

TABLE 1.3

THE GENERAL COMPOSITION OF BONE Component

Figure 1.21 Electron micrograph of a section of a bone sur-

face undergoing resorption. Calcified bone appears black on the left. The main part of the picture is occupied by the cytoplasm of the osteoclast: it consists of complex folds and projections that abut on the bone at the left. (Reprinted with permission from Hayes WC. Biomechanics of cortical and trabecular bone: implications for assessment of fracture risk. In: Mow VC, Hayes WC, eds. Basic Orthopaedic Biomechanics. New York, NY: Raven Press, 1991.)

Percentage

Solids

92%

Water

8%

Solid composition Mineral phase Organic phase

65% 35%

Mineral phase composition Calcium Phosphorous, Mg, Na, other ions

60% 40%

Organic phase composition Collagen Cells Lipids, glycosaminoglycans, noncollagen proteins, etc.

95% 3% 2%

Reprinted with permission from Wiesel SW, Delahay JN. Principles of Orthopaedic Medicine and Surgery. Philadelphia, PA: Saunders; 2001.


TABLE 1.4

MOLECULAR DEFECTS IN THE HERITABLE DISEASES OF COLLAGEN Syndrome

Defect

Ehlers–Danlos syndrome Types I–III Type IV Type VI Type VII Type IX

Fibrillogenesis defects Decreased type III collagen Lysyl hydroxylase Persistence of N-propeptide Defective cross-linking

Marfan syndrome Osteogenesis imperfecta Type I Type II Type III Menkes syndrome

Abnormal pro-α 2(I) affecting the structure of type I collagen Probable deletion of d(1) gene Defective secretion of α-chains Decreased pro-α 2(I) chains Cu metabolism abnormality causing defective cross-linking

Reprinted with permission from Wiesel SW, Delahay JN. Principles of Orthopaedic Medicine and Surgery. Philadelphia, PA: Saunders; 2001.

Mineral Phase of Bone Approxim ately two-thirds of bon e m atrix by weight and approxim ately one-half by volum e are m ineral. The m ost com m on form is calcium hydroxyapatite crystal. These crystals are 580 Å and are described as tubular h exagons. Although hydroxyapatite is the m ost com m on form of the m ineral present, there is also a sm all am ount of am orphous calcium phosphate. Debate still exists as to whether this form of m ineral is m erely a finely divided apatite crystal. As n oted earlier, the unique feature of the bone m in eral is its ordered association with bone collagen. The m ineral is arranged along the long axis of the collagen fibril with an in terval of 600 to 700 Å. This periodicity is identical to the norm al periodicity of th e unm ineralized collagen fibril. Studies h ave clearly in dicated th at th e m in eral is foun d in the “hole zones” of the quarter stagger arrangem ent of the collagen m olecules. Approxim ately 50% of the total m ineral in bon e is con tain ed in th ese “h ole zon es.” Sim ilarly, noncovalent “interaction s” have been identified between the collagen an d the apatite. This “bonding” bestows on this two-phase m aterial properties that are greater than th e sum of the parts. The rem aining bon e m ineral is postulated to be con tain ed in th e cen tral core of th e collagen fibril.

Mineralization Th e process of m in eralization occurs in two distin ct ph ases: initiation followed by proliferation or accretion. The process of initiation requires a com bin ation of even ts. Specifically, in crease in the local concentration of precipitatin g ions, followed by exposure of th ose ion s to m in eral nucleators, begins the propagation process. Inhibitors and reg-

19

ulators m odulate th e form ation of apatite. Th e process of in itiation requires m ore en ergy th an does th e addition of m in eral to already existin g crystals. Because sufficien t en ergy is n ot always readily available, som e h ave proposed that the in itial m ineral deposited is a m etastable precursor of apatite, an d as m ore en ergy becom es available, th is un stable precursor is converted to th e m ore stable form s of apatite crystal. Within the extracellular en vironm ent are sm all structures referred to as “m atrix vesicles.” Th ese structures h ave been credited with th e ability to facilitate calcification by concentrating calcium ions, by providing a m icroenvironm en t free of in h ibitors, an d by providin g th e n eeded en zym es for m atrix m odification . Once th e initial process of deposition occurs, the second ph ase of proliferation or accretion can begin. At this tim e, addition al m in eral is added to th at wh ich is already presen t. As previously discussed, this m ineral is inserted into the “hole zon es” of the collagen fibers. Obviously, th e furth er deposition of m in eral will serve to im prove th e rigidity of the overall m atrix. Recen tly, th e im portan ce of calcium -bin din g protein s within th e bon e m atrix h as been emphasized. These noncollagen ous protein s are felt to be critical in th e facilitation of m in eralization with in th e collagen . Specifically, ph osph oprotein s, osteon ectin , an d som e of th e GLA protein s h ave been cited. Osteocalcin , on e of th e recen tly isolated GLA protein s, is said to accoun t for 10% to 20% of all th e n oncollagenous protein s in bon e. Th e role of th ese GLA protein s is still bein g actively in vestigated.

Bone Resorption Th e process of bon e form ation clearly appears to be m ore com plex th an th at of bon e resorption . Th is process in volves th e hydrolysis of collagen an d th e dissolution of bon e m in eral. It is well docum en ted th at th e osteoclast m ust sim ultan eously do both . Th ere is n o m ech an ism in place for th e sim ple dissolution of bone m ineral, leaving unm in eralized osteoid. As described earlier, th e osteoclast is th e critical cell for the resorption of bone. The brush border of this m ultinuclear cell is always in con tact with th e bon e th at is actively bein g resorbed. Electron m icrograph s of th ese cells dem on strate an in creased n um ber of m itochondria adjacent to the brush border, suggestin g th eir fun ction in th e tran scellular transport of calcium ion . In addition, n um erous lysosom es are identified in this area, which seem s appropriate, considerin g th e fact th at th ese organelles contain num erous hydrolytic en zym es. Th e process is th ough t to be in itiated by th e lysosom al degradation of bon e collagen . On ce th e in itial degradation begin s, fragm en ts of th e disrupted collagen are taken up by th e cell an d are furth er hydrolyzed. Collagenase cleaves tropocollagen into two m ajor fragm ents. Parathyroid horm one seem s to directly increase the local con centration of collagen ase en zym e. Con siderin g th e role of parathyroid

20


horm one in calcium release, this effect seem s appropriate. Coin ciden t with th e degradation of th e collagen is th e solubilization of th e hydroxyapatite crystal.

Bone Remodeling Th e rem oval of bon e an d its subsequen t redeposition are an on goin g process. Th e process is som ewh at age depen den t. Approxim ately 80% of total skeletal m ass is cortical bon e, an d approxim ately 20% of skeletal m ass is can cellous bon e. In th e youn g skeleton , turn over rates can be as h igh as 50% per year in certain diaphyseal bon es. With agin g, this num ber decreases to 2% to 3% per year. The process of resorption begin s with a wave of osteoclastic activity in th e form of “cutting cones.” These osteoclastic cuttin g heads re-

Sectio n 3

m ove old bone, and in th eir wake, new osteoblastic activity can be seen . Th e process of bon e rem odelin g an d th e rates of th is process are un der th e con trol of n um erous local an d system ic factors.

RECOMMENDED READINGS Buckwalter JA, Glim ch er MJ, Cooper RR, Recker R. Instruction al course lecture: bone biology. Part I: structure, blood supply, cells, m atrix, and m ineralization . J Bone Joint Surg Am. 1995;77:1256 –1275. Buckwalter JA, Glim ch er MJ, Cooper RR, Recker R. Instruction al course lecture: bone biology. Part II: form , m odeling, rem odeling, and regulation of cell function. J Bone Joint Surg Am. 1995;77:1276 – 1289. O’Driscoll SW. Curren t con cept review: th e h ealin g an d regen eration of articular cartilage. J Bone Joint Surg Am. 1998;80-A(12):1796 – 1812.

Bio mechanics and Bio materials John A. Zavala

John N. Delahay

INTRODUCTION Th e study of m ech an ics is critical to un derstan din g of th e prin ciples of orth opaedic surgery, in term s of both the norm al functionin g of the m usculoskeletal system and the aberrant behavior due to alterations of the m echanical environm en t. Th e study of biom aterials is also an integral part of th e field in asm uch as m any im plan ts are used in th e m an agem en t of m usculoskeletal affliction s. An un derstan din g of th ese im plan ts an d th e properties of th e m aterial from wh ich th ey are m ade is critical to an appreciation of their use. The purpose of this chapter is to assist the reader in un derstanding th e basic principles of biom ech an ics an d biom aterials.

BIOMECHANICS Forces A force is simply defined as a push or pull and technically is on e of th ree types. 1. Tensile force, which tends to pull objects apart 2. Compressive force, wh ich ten ds to push objects togeth er 3. Sh earin g force, wh ich ten ds to m ake on e part of an object slide over an im m ediately adjacen t part. Forces can act separately or in com bin ation with on e an oth er. It is importan t to un derstan d th at forces are essen tially vector quantities. Th at is, they h ave a m agn itude, a lin e of application, a direction or sense, and a point of ap-

plication . If any on e of th ese four ch aracteristics is ch an ged, th e en tire vector itself is altered. Wh en m ultiple forces act on a structure, it is possible to resolve th ese forces in to a sin gle vector. Most loadin g situations feel the effect of forces. Therefore, the techniques of vector analysis perm it the sum m ation of these forces and a graphic dem onstration of their com bination . Joints are n o exception . Multiple m uscle forces ten d to pull structures with varyin g m agn itudes, poin ts of attach m en t, an d directions. These forces require resolution in order to be able to evaluate th e loading environm ent. By resolving these m ultiple forces into a single vector, their net effect can be anticipated (Fig. 1.22). Forces th at act at differen t poin ts on a body ten d to result in m om en ts. Mom ents cause bending or rotation of the body in question . A m om en t can be expressed as th e product of th e force an d th e perpen dicular distan ce from th e lin e of action of the force to the axis of rotation . It is importan t to keep in m in d th at th e distan ce (d) in the stan dard form ula for m om ent ( M = F × d) is th e perpen dicular distan ce from th e lin e of application to th e axis of rotation . In the seesaw example, each child creates a bending m om en t on th e board. Th is m om en t ten ds to ben d th e board at th e fulcrum . In Figure 1.23, these two m om en ts are represented by Ba an d Cb. For th e system to be in equilibrium , th ese m om en ts m ust be equal. Th ere are n um erous examples in th e m usculoskeletal system of th e effects of a m om ent. The classic exam ple frequen tly used is th at of th e ben din g m om en t felt by a dynam ic hip compression screw used to fix an intertroch an teric fracture. Am om en t is created by th e vertical


F quad

21

F pat F reaction

F pat

F quad F reaction

Figure 1.22 Example of calculation of forces in the knee joint. The patellofemoral joint reaction force, Freaction , is the vector parallelogram sum of the quadriceps force, Fquad , and the patellar tendon force, Fpat . (Reprinted with permission from Damron TA, Morris CD, Tornetta P, et al. Oncology and Basic Science. Philadelphia, PA: Lippincott Williams & Wilkins, 2007.)

force (Wy) actin g at distan ce (d), which is tending to bend the plate. With a higher angle plate, d will decrease; h en ce, the bending m om ent will decrease (Fig. 1.24). Th e term torque is occasion ally used to indicate a m om en t that produces rotational m otion about an axis. Essen tially, a m om en t and a torque can be considered to be the sam e. Despite th e fact that th e form ulas for th ese forces are different, they produce sim ilar results—bending or rotation about an axis. A special example of torsional m om ents is the force couple. This force system is created by two equal, parallel forces th at are n ot collin ear. Th eir resultan t effect is additive and is represented by F × d. For an object to be in equilibrium , all of th e forces m ust equal zero and all of th e m om en ts m ust equal zero. Th e con cept of equilibrium is im portan t, if on e is to use m ath em atical m odels to determ in e th e loadin g of various join ts and the effect of load on various implants.

C

B

b

a

A

Figure 1.23 Forces on opposite sides of the axis. In equilibrium,

B + C (downward forces) = A (upward force). (Reprinted with permission from Le Veau B. Williams and Lissner: Biomechanics of Human Motion. Philadelphia, PA: Saunders, 1977.)

Figure 1.24 Bending moment (M ) on a compression hip screw

is calculated as follows: M = Wy × d Where d = distance from line of application to axis of rotation (B ) and Wy = component of force W (body weight) acting along the y axis. (Reprinted with permission from Wiesel SW, Delahay JN. Principles of Orthopaedic Medicine and Surgery. Philadelphia, PA: Saunders, 2001.)

Th e form ula for force is F = m × a (m ass × acceleration), wh ich allows on e to defin e force in term s of any un it desired. Th e stan dard force un it is th e Newton , wh ich is defin ed as th e force n eeded to accelerate 1 kg of m ass 1 m / s2 . In ertia is th e resistin g force th at ten ds to keep th e 1 kg of m ass in its existin g state of m otion. Th e term weight represents a special form of force, specifically that which results from gravity. The force with wh ich a given m ass is attracted toward th e cen ter of a gravitation al body is represen ted by its weight. Unfortunately, the term kilogram is widely used to in dicate weigh t an d m ass. Th erefore, th e use of th at term creates confusion as to the force. The term Newton is th e preferred term to in dicate force.

Elasticity, Stress, and Strain Th e orth opaedic surgeon deals with m any solid structures, som e biologic, such as bone and cartilage, and others nonbiologic, such as m etals an d plastics. In th e pure scien ce of m ech an ics, on e assum es th at th e objects or bodies an alyzed are rigid. In biologic system s, this is not a valid assumption . It is importan t to be able to consider the change in shape or volum e of an object as external forces are applied. Th e elasticity of m atter is dem on strated simply by a divin g board th at ben ds un der load an d return s to its original shape when the load is rem oved. For m any m aterials, th is ability to return to its origin al con figuration is n early perfect; th ese m aterials are said to be elastic (Fig. 1.25). Th e beh avior of elastic m aterials is govern ed by Hooke’s law, which states th at the deform ation of an elastic body is directly proportion al to th e m agn itude of th e applied force provided th at th e elastic lim it is n ot exceeded. Th e an alysis of th e beh avior of a m aterial h in ges on th e prin ciples of stress an d strain . Stress is defined as a force per un it area of m aterial an d is a m easurem en t of th e in ten sity

22

Orthopaedic Surgery: Principles of Diagnosis and Treatment Yield point (proportional limit)

8 Yield point

7

Ultimate strength

6 Force (N)

Max force 5 X Breaking point

Stress

4

E

3 2

Stiffness

Failure

Elastic zone

1 0

0

2

4

6

8

10

12

Displacement (mm)

Figure 1.25 Example of a force-displacement loading curve for

a linear, elastic structure. (Reprinted with permission from Damron TA, Morris CD, Tornetta P, et al. Oncology and Basic Science. Philadelphia, PA: Lippincott Williams & Wilkins, 2007.)

of th e force. Stress essen tially represen ts th e in term olecular resistan ce with in an object to th e action of an outside force that has been applied. Stress cann ot be m easured directly; however, its m agnitude can be calculated by various form ulas. Th e use of th ese form ulas to determ in e a m aterial’s stress-related properties is predicated upon th e fact th at the m aterial is isotropic. Th is description implies a h om ogen eity of th e m aterial such th at th e physical properties are th e sam e regardless of th e direction of testing. Conversely, in an an isotropic m aterial, th e physical properties vary with the direction of testing. There are two basic types of stress. Normal stress is perpen dicular to th e plan e of any cross section of m aterial. Th erefore, compressive forces an d ten sile forces will gen erate a n orm al stress in th e structure. Shear stress is defin ed as the intensity of force parallel to the surface on wh ich it acts. When forces create stress with in a structure, th ey typically produce strain . Strain is defin ed as the deform ation within a structure. Before a structure or a m aterial breaks, it usually stretch es or ben ds. Th is stretch in g or ben din g prior to failure is called “strain ,” an d it is defin ed as th e ch an ge in un it len gth or an gular deform ation of a m aterial subjected to load. Sim ilar to stress, th ere are two types of strain : normal strain, which is caused by either stretchin g, wh ich results from tensile force, or shortenin g, wh ich results from compressive force, and shear strain, wh ich is defin ed as th e an gular deform ation suffered by an object subjected to a sh earin g force. At th is poin t it is n ecessary to clarify th e term s force, deform ation , stress, an d strain . Force an d deform ation are said to be structural properties. Thus, wh en a force is applied to a given structure, som e degree of deform ation is produced. Stress an d strain , on th e oth er h an d, are said to be m aterial properties; th at is, th ey are th e sam e for a given m aterial n o m atter wh at structure is m ade from th at m aterial. Essentially, stress is force norm alized per unit area.

Strain Plastic strain deformation

Figure 1.26 The stress–strain curve. (Reprinted with permission from Miller MD. Review of Orthopaedics, 2nd ed. Philadelphia, WB Saunders, 2008.)

Stress–Strain Curve Wh en an elastic m aterial is subjected to an in creasin g ten sile stress th at carries the m aterial beyond the elastic lim it, a stress–strain curve can be plotted (Fig. 1.26). In considerin g th is curve, th e lin e between zero an d th e yield poin t is straight, sh owin g th at stress is proportion al to strain for sm all strains in accordan ce with Hooke’s law. A specim en will exh ibit lin ear elastic beh avior up to a certain lim it, wh ich is referred to as th e “yield poin t.” Beyon d th e yield poin t stress is n o lon ger proportion al to strain , an d th e deform in g object is n o lon ger capable of regain in g its original length when the disturbing force is rem oved. If the force is rem oved beyond the yield poin t, the strain retraces the broken line back to the baseline and the object is left with perm an en t deform ation . Th e importan t features of this curve are as follows: Yield point is th e stress at wh ich m arked in crease in deform ation occurs without an in crease in load. Ultimate tensile strength (UTS) is the highest point on the curve. Th is is th e m axim um apparen t stress th at th e m aterial can with stand. UTS is frequently referred to as the strength of th e m aterial. Elastic region is th e portion of th e curve from zero to th e yield poin t. This portion of the curve is typically linear. It is with in th is portion th at stress is proportion al to strain and Hooke’s law is valid. Plastic region is the portion beyond the yield poin t where the deform ing strain is not proportion al to the applied stress. Modulus of Elasticity is represented by the slope of the line in the elastic portion. The m odulus is also a m aterial property. Th e h igh er th e n um ber, th e greater the hardn ess of the m aterial. Essentially, this m odulus in dicates th e poun ds per square in ch (psi) of


stress that m ust develop to gain a certain am oun t of strain. Th ese curves can be used to compare th e beh avior of various m aterials. Specifically, in orth opaedics, on e can compare the m aterial properties of th e com m only used m etals; cobalt-ch rom e alloy, titan ium alloys, an d stain less steel as they relate to cortical and cancellous bone.

Loading Forces can load an object in a n um ber of ways. Th e object frequently used to m odel loading m ech anism s is a solid bar of m aterial or a beam . Th is bar of m aterial can be used to compare th e ch an ges th at are seen as various loads are applied and as the direction of these loads is altered. Tensile koading results from a force applied alon g th e lon g axis of th e bar, stretch in g th e bar an d causin g any given crosssection al area to decrease in size. Compressive loading con versely will ten d to sh orten th e bar an d will ten d to in crease any given cross-section al area. Th e specific dim en sion s of the chan ge can be determ ined usin g Poisson’s ratio. Bending is actually a form of composite loading. Usin g the m odel of a cantilever beam in which the m aterial is fixed at on e en d an d loaded at th e oth er, isolated loadin g pattern s can be appreciated as th e beam is ben t. On th e convex side of bendin g, tensile stresses are generated and ten sile strain is observed. On th e opposite, or con cave, side of th e ben d, compressive strain is n oted, resultin g from compressive stresses generated. Located in the center of the beam is a n eutral plan e, wh ere th e stresses are zero. Th e prin ciples are applicable to th e failure of lon g bon es. Wh en subjected to bending loads, the bones beh ave m uch like a cantilever beam , that is, tensile stress on the convex side an d compressive stress on th e con cave side. The way in which th e m aterial is distributed over the cross section in any beam of m aterial will alter the loading pattern . An im portan t property, th e area m om en t of in ertia, defin es th is m aterial distribution to ben din g of a structure un der static loadin g. Torsional loading results wh en a torque is applied to a cylinder of m aterial. In doing so, stresses are created with in this cylinder. Th e polar moment of inertia is that property of the cross-sectional area of a cylindrical structure th at is a m easure of the distribution of th e m aterial about an axis perpen dicular to th e cross section (Fig. 1.27). For example, the distribution of the m aterial at greater distances from this central axis tends to improve the torsional rigidity of the cylinder in question. The polar m om ent of inertia can dram atically affect torsion al loadin g an d, as such , plays an important role in the fracture patterns seen in long bones. For example, th e polar m om en t in th e proxim al tibia is greater th an in th e distal tibia. Th erefore, torsion al failure is predictably m ore likely to occur distally, and clinically, that is the case.

Cross-sectional shape

Square

23

Polar moment of inertia (J)

0.141 h4

h h

Solid rod

Thick-walled tube

r 4/2

r

ri

ro

(r o4 – r i4)/2

r

r 3t/2

t Thin-walled tube

Figure 1.27 Cross-sectional views and the corresponding moments of inertia. (Reprinted with permission from Damron TA, Morris CD, Tornetta P, et al. Oncology and Basic Science. Philadelphia, PA: Lippincott Williams & Wilkins, 2007.)

Com bined loading occurs in m ost structures, biologic an d n on biologic. Most fractures are th e result of a com bin ation of m echanism s: compression, tension, shear, bendin g, an d torsion .

Stress Concentration Effects Stress of a sm ooth bar of an isotropic m aterial is rather easy to calculate. However, if th e m aterial is an isotropic or if there is a m issing section, the calculation becom es far m ore complex. The principle of stress concen trators (stress raisers) h as broad clin ical sign ifican ce. An im al studies h ave dem on strated th at th e presen ce of a screw or drill h ole can decrease th e ability of th at bon e to store en ergy by 70% wh en stressed torsion ally. Addition ally, followin g rem oval of a screw from a lon g bon e, 8 to 10 weeks are required for the stress concentration effect to be negated. An open section defect is created when a large segm ent of bon e is rem oved from th e circum feren ce of a lon g tubular bon e. Th e cortical discon tin uity fun ction s as a large stress raiser. In th e h um an tibia, an open defect can reduce load to failure and ability to store energy by up to 90%.

24


Viscoelasticity Many n on biologic m aterials beh ave in a purely elastic m an ner. Th at is, the stress and strain are linearly proportional an d con stan t. Most of th e m etals an d ceram ics th at are used in orth opaedics beh ave in a classically elastic fash ion . Polym ers, on the other hand, behave differen tly. Polym ers sh ow a degree of rate depen dence. That is, the stress developed depen ds n ot on ly on th e strain but also on th e tim e taken to reach th at strain . Th is beh avior of rate depen den ce is referred to as “viscoelasticity.” For a viscoelastic m aterial, th e stress developed depen ds on th e strain an d th e tim e, th at is, th e stress–strain curve can be altered by ch an gin g th e strain rate. Th e m odel frequen tly used to dem on strate biologic viscoelastic beh avior is th e earlobe (Fig. 1.28). Using this curve as a reference one can identify th ree ph en om en a th at are typical of a viscoelastic m aterial.

Damping Th is ph en om en on is explain ed by th e syrin ge in wh ich th e resistan ce or force required to m ove th e plun ger in to th e syrin ge increases as the rate of m ovem ent of the plunger in creases. Th is property of a m aterial, offerin g greater resistan ce as th e speed is in creased, is called “dam pin g.” Creep Followin g th e sudden application of a given load, th ere is an in itial deform ation , followed by a subsequen t addition al deform ation , wh ich occurs as a fun ction of tim e un der th e sam e in itial load. For exam ple, we lose som e h eigh t durin g the course of the day. This loss of height is due to creep of th e in tervertebral disks. Slowly over tim e, th ey th in down ; th e n et effect wh en sum m ated is loss of h eigh t.

Figure 1.28 Principles of Viscoelastic behavior. As load is ap-

plied to a viscoelastic material, immediate deformation (A) occurs. With the load held constant, slow progressive additional deformation (creep) continues to occur with time (B). When unloading occurs, there is immediate recoil (C), followed by a prolonged period of stress relaxation (D). (Reprinted with permission from Wiesel SW, Delahay JN. Principles of Orthopaedic Medicine and Surgery. Philadelphia, PA: Saunders, 2001.)

Relaxation Relaxation describes a decrease in stress within a deform ed structure over tim e, wh en the deform ation is held con stant. Wh en a Harrin gton rod is used on th e con cave side of a scoliotic curve to straighten th e spin e, there is an im m ediate tightening of th e ligam entous structures on the concavity of the curve. The stresses within th ose ligam entous structures lessen with tim e.

Mechanical Properties of Tissues Bone Cancellous bon e is an organ ized, load-bearing m aterial. By its very n ature, cancellous bone is anisotropic; therefore, its beh avior varies in th e direction of loadin g. It ten ds to be stiffer in ten sion th an in compression. It also fails at lower strain in th e direction parallel to the axis of the spicule. Th e m ajor differen ce between cortical an d can cellous bon e is th e degree of porosity. Because of its greater porosity, can cellous bone behaves very poorly during compression . Despite its ability to absorb energy upon impact, the application of significant loads will cause failure at strain rates of 0.5. At th at poin t, crush in g of th e trabeculae h as already begun to occur. As is the case in a vertebral body compression fracture, once a certain am ount of compression and failure has occurred, th e overall construct does becom e som ewh at stiffer. Th is ability to becom e stron ger with th e application of compressive load is in con trast to the application of tensile load. Once yielding of cancellous bon e occurs in ten sion , rapid fracture is likely to follow. Th e ability to absorb en ergy in ten sile loadin g is m arkedly less than in compressive loading. Cortical bon e is a un ique tissue. In ligh t of its organ ized, m ineralized structure, it is clearly designed to carry load. Th e classic lam ellae are 3 to 4 µ m thick. The haversian system s are suited an d design ed to with stan d ben din g about their long axis. Cortical bone, although viscoelastic by nature, is characterized by its elastic properties, especially at low strain rates. The ability of bone to deform plastically is a function of its hydration. In the fully hydrated state, cortical bone exh ibits elastic beh avior up to 0.3% strain. Wh en it is dry, bon e exh ibits a h igh er m odulus in both ten sion an d compression , but it is m ore brittle. Th erefore, in its norm al hydrated state, bon e h as a far greater ability to absorb strain en ergy. Th e fact th at bon e is viscoelastic on ly en h an ces its beh avior in th e m ech an ical en viron m en t with in wh ich it m ust fun ction . Th is ability to beh ave differently at different strain rates protects the structure from failure with in a wide ran ge. Th e m ech an ical properties of bon e are in tim ately related with its ch em istry. Articular Cartilage Th e biom ech an ical beh avior of articular cartilage can best be un derstood by appreciatin g th e fact th at it is a biph asic tissue. Cartilage is a fluid-filled porous m edium . Th e ch em ical con stituen ts of th e organ ic m atrix an d th e


interstitial water interact with each oth er to create a unique tissue capable of impact load absorption and near friction less interfaces. Articular cartilage is viscoelastic and therefore is capable of creep. The ability of cartilage to creep is important in th e norm al lubricating m echan ics of diarthrodial join ts. As th e cartilage is loaded, fluid is expressed, creatin g what h as been referred to as “an elastohydrodynam ic m echanism of joint lubrication .”

Collagenous Tissues Ligam ent and tendon are essentially passive structures and inh erently are not respon sible for active m otion. They are composed of three fiber types: collagen, elastic fibers, an d reticular fibers. Both ligam en t an d ten don fun ction prim arily in tension. Their m echanical properties are a function of th e orientation of the fibers, the m aterial properties of th e fibers, an d th e relative proportion of collagen to elastin . Structurally, th e direction of th e fibers varies between the tendon and the ligam ent. In tendon, the collagen bundles are parallel, as on e would expect, m akin g th em th e ideal tissue to withstand high tensile load. Ligam ent m ust function throughout the full range of a given joint. Therefore, the fiber orien tation m ust be far m ore diverse. Typically, nonparallel arrays of collagen fibers are seen. While ligam ents, like tendons, are prim arily composed of collagen fibers, th ey con tain a m uch larger portion of elastic fibers. Th e properties of th e two fibers are som ewh at different. Collagen is a ductile m aterial, showing a stress–strain curve sim ilar to that of bone. The elastic fibers show significan t deform ation or strain with relatively m inim ally applied load, but on ce failure occurs, it occurs quickly. Th e size an d sh ape of a ligam en t are critical issues in its behavior. As one would expect, the larger the crosssection al area, th e stronger the ligam en t. The speed of loading, as is the case with other viscoelastic biologic tissues, also plays a role in ligam ent failure. The anterior cruciate ligam ent (ACL) has been shown to function m uch like bon e in th at, as th e loadin g rate in creases, th e ligam en t is able to store m ore energy prior to failure. Unfortunately, wh en th e ligam en t does fail at th ese h igh rates, it ten ds to be with in th e substan ce of th e ligam en t with disastrous con sequen ces. At lower loading rates, the bony insertion of th e ligam en t is m ore vuln erable an d th erefore th e tibial spine avulsion is m ore likely. This data suggest that with an increase in loading rate, th e strength of the bone increases m ore than the strength of the ligam ent. Hence, the ligam ent failure occurs at h igh er loading rates.

BIOMATERIALS AND IMPLANTS In th is section , th e prin ciples of biom aterials will be reviewed as th ey relate specifically to orthopaedic implants. Obviously, any foreign implant needs to survive in the environm en t in which it is placed. Biocompatibility is one of

25

TABLE 1.5

GENERAL ADVANTAGES AND DISADVANTAGES OF STAINLESS STEEL Advantages Cheap raw elements Good biocompatibility Disadvantages Some grades not suitable for long-term implantation due to fatigue failure Galvanic corrosion to CoCr and titanium Nickel sensitivity Poor wear properties Reprinted with permission from Damron TA, Morris CD, Tornetta P, et al. Oncology and Basic Science. Philadelphia, PA: Lippincott Williams & Wilkins, 2007.

th e m ajor con cern s in implan t developm en t. As implan t use h as becom e m ore widespread, th e problem s related to th e stren gth of th e implan t h ave been carefully studied. At th e presen t tim e, it is probably fair to say th at m ost im plan ts curren tly available are able to adequately with stan d th e loads placed upon th em .

Metals In orth opaedic surgery, essen tially, th ree m etallic alloys are employed for im plan t fabrication : (a) stain less steel, (b) chrom e-cobalt, and (c) titan ium . Stain less steel is a m ixture of prim arily iron an d n ickel. It h as th e lowest yield stren gth of th e th ree alloys. However, its ben efit is a lon g plastic region of th e stress–strain curve, m akin g it the m ost ductile of th e th ree m aterials. Th erefore, it is able to absorb large am ounts of strain energy prior to failure (Table 1.5). Most fracture fixation implants are fabricated from stainless steel. Ch rom e–cobalt alloy has the highest UTS, and it is th erefore th e stron gest. It also h as th e h igh est m odulus of elasticity, m akin g it th e stiffest of th e th ree m aterials (Table 1.6). Titan ium -based alloys in clude alum in um an d van adium to h arden th e m aterial. Th ese alloys h ave excellen t corrosion resistan ce an d good fatigue properties (Table 1.7). However, wear h as been a sign ifican t problem . Th eir m odulus is the lowest of th e three alloys. Therefore, m any suggest th at these are th e best for implan t application s, because th eir m odulus is closest to th at of bon e. However, it is importan t to realize that m odulus values of n one of th e th ree are even close to th e m odulus value of bon e. In addition , their UTS is below that of ch rom e-cobalt, despite th e fact th at th eir yield stren gth is som ewh at h igh er. Additionally, their ability to deform plastically is lim ited. Th e ch oice of a m etal for a given application h as h istorically been som ewhat idiosyn cratic. Dependin g on the application, th e cost, the surgeons’ prejudice, and other factors, differen t m etals h ave been ch osen over th e years.

26


TABLE 1.6

GENERAL ADVANTAGES AND DISADVANTAGES OF COBALT-BASED ALLOYS Advantages Good biocompatibility Fatigue resistant Wear resistant Low galvanic corrosion to titanium

Linear

Branched

Disadvantages Galvanic corrosion to stainless steel Concerns regarding nickel content Cobalt and chromium ion release High elastic modulus Expensive Difficult to process Reprinted with permission from Damron TA, Morris CD, Tornetta P, et al. Oncology and Basic Science. Philadelphia, PA: Lippincott Williams & Wilkins, 2007.

Crosslinked Figure 1.29 Polymer chain arrangements. (Reprinted with permission from Damron TA, Morris CD, Tornetta P, et al. Oncology and Basic Science. Philadelphia, PA: Lippincott Williams & Wilkins, 2007.)

Polymers Ultra High Molecular Weight Polyethylene At th e present tim e, the polym er of ch oice in the fabrication of im plan t com pon en ts is ultra h igh m olecular weigh t polyethylen e (UHMWPE), wh ich is essen tially a lon g-ch ain threadlike m olecule of very high m olecular weight chains of varyin g len gh ts (Fig. 1.29). Th ese ch ain s are m esom orph ic, in th at th ey h ave regular atom ic arran gem en ts in som e direction s, but n ot in oth ers. As on e would expect, th e polym ers get stron ger as th e ch ain len gth in creases. Stren gth can be improved by increasing the cross-lin king. Polyethylen e itself is a wh ole class of compoun ds, wh ich differ by m olecular weigh t, bran ch in g, den sity, an d capacity for crystallization . In gen eral, th e h igh er th e m olecular weigh t, th e higher the crystallinity, and th e harder th e product. Th e m ech an ical properties depen d on th e m olecular weigh t, th e

TABLE 1.7

GENERAL ADVANTAGES AND DISADVANTAGES OF TITANIUM-BASED ALLOYS Advantages Excellent biocompatibility Relatively low elastic modulus Spot welding to itself in taper junctions Low galvanic corrosion to Co–Cr–Mo alloy Disadvantages Poor wear properties Notch sensitive Concern with vanadium and aluminum content in specific alloys Reprinted with permission from Damron TA, Morris CD, Tornetta P, et al. Oncology and Basic Science. Philadelphia, PA: Lippincott Williams & Wilkins, 2007.

den sity, an d th e crystallin ity. UHMWPE is a th erm oplastic resin . Th is m ean s th at th e polym er soften s with in creasing temperature, m akin g m olding an d m anufacture feasible an d allowing a superior finish to be achieved. This process is reversible with reheating of the m aterial. Th is property explain s th e reason th at implan t compon en ts can n ot be h eat sterilized. Th ey will distort an d th eir properties will be altered.

Polymethyl Methacrylate Polym ethyl m eth acrylate (PMM) has frequently been referred to as “cem ent” and is frequently used to secure orthopaedic implants. It is essentially a luting agent, which creates a m echanical interlocking bond between adjacent surfaces. A “glue’’or adhesive, on the other h and, creates a ch em ical bond between th e surfaces. PMM is supplied in the form of a white powder, which consists of sm all balls of PMM polym er, an d a vial of m on om er th at con tain s a stabilizer to preven t polym erization un til after m ixin g. Wh en the m onom er is m ixed with the polym er, benzoyl peroxide catalyzes th e process of polym erization. This particular polym eric m aterial is a th erm osettin g resin . Th e polym erization occurs in the presence of heat. However, once th e m aterial has set, no am ount of heating can reverse its configuration . Th e sin gle m ost importan t factor in th e settin g tim e of PMM is the am bient temperature of th e room . The cooler the room , the longer the setting tim e. In addition, the type of m ixing, the rate of m ixing, and th e patient’s body tem perature all will alter th e rate of settin g.

Implant Failure A n um ber of m ech an ism s can cause th e failure of a given implant. Metal, plastics, and cem ent are all vulnerable to


Third bo dy

Abras ive

Adhe s io n

Fatig ue

Figure 1.30 Examples of material wear. (Reprinted with permission from Damron TA, Morris CD, Tornetta P, et al. Oncology and Basic Science. Philadelphia, PA: Lippincott Williams & Wilkins, 2007.)

various types of failure. Mechanical as well as ch em ical breakdown of th e im plan t can occur.

Fatigue Most implants are m ade to tolerate th e loads encountered below th eir yield poin t. Som e im plan ts will fail un der extrem e cyclic loading con ditions due to the process of fatigue. Fatigue is th e result of repetitive or fluctuating application of load. Each m easured load application is below the yield point, but when applied cyclically, fatigue failure with crack propagation can occur. Th e en duran ce lim it is that critical load below which n o am ount of cyclic loading will produce failure. Im plan ts sh ould be design ed to fun ction below th e en duran ce lim it. As loads exceed th e en duran ce lim it or are applied cyclically, fatigue of the implan t m ay occur. Ductility does n ot in an d of itself preclude fatigue, because on ly a m oderate am oun t of plastic deform ation of an implant can be tolerated before failure is seen. Imperfection s in design or fabrication such as cracks, notch es, impurities, and sharp an gles predispose th e implants to fatigue failure. Wear Wear is th e m echan ical rem oval of m aterial from th e surfaces in relative m otion to each oth er (Fig. 1.30). For exam ple, th e slidin g of on e object over an oth er produces wear.

27

It is key to rem em ber th at wear is a m ech an ical process. When two surfaces are loaded togeth er in in tim ate contact, th e surface rough n ess or asperities create poin ts of frictional contact. It has been dem onstrated th at fragm ents from one surface m ay adhere to the opposite surface. Typically, th is adh eren ce results from in term olecular action s. As the surfaces continue to rub against one an oth er, further disruption of surface sm ooth n ess can occur. Th is process is referred to as “adh esive wear.” Abrasive wear occurs wh en a h ard rough surface slides on a softer m aterial. Th e h arder m aterial ten ds to cut grooves in the softer m aterial. The presence of particulate debris between th e surfaces th at m ay h ave arisen from th e process of adh esive wear accen tuates th e process of abrasive wear. When fragm en ts are present between the bearing surfaces, th e process is referred to as “third-body wear.’’As the distan ce over wh ich the bearing surfaces slide will increase over tim e, there tends to be a volum etric increase in the num ber of wear particles.

Corrosion Corrosion is the electrochem ical breakdown of a m etallic surface. The ion ic transfer, from on e m etal to a m ore base level, produces th e surface breakdown of a m etallic implant. Stainless steel is th e best example of the corrosion problem . If th e surface coatin g of a m etallic im plan t were to be disrupted, the un derlying base m etal is exposed to th e surroundin g m ilieu. Depending on the base m etal, corrosion m ay th en proceed. In the case of stainless steel, exposure of th e base m etal (iron) usually stim ulates an obvious corrosive respon se. If exten sive, blacken in g of th e adjacen t soft tissues can be seen . The surface protective layer of an implant is referred to as the “passivation layer.” The coating is designed to protect the implant from a corrosion attack and is applied at the tim e of m anufacture.

RECOMMENDED READINGS Jazrawi LM, Kum m er FJ, DiCesare PE. Altern ative bearin g surfaces for total join t arthroplasty. J Am Acad Orthop Surg 1998;6(4):198 –203. Lucas GL, Cooke FW, Friis EA. A Primer of Biomechanics. New York, NY: Sprin ger, 1998. Sch m alzried TP, Callah an JJ. Curren t con cepts review: wear in total h ip an d kn ee replacem en ts. JBJS Am 1999;81:115 –136.

Epidem iology and Biostatistics in Orthopaedic Surgery Keith D. Baldwin

2

G. Ru ssell Huf fm an

INTRODUCTION Epidem iology, biostatistics, an d eviden ce-based m edicin e are the tools by which n ew knowledge is attain ed and in corporated into the practice of orthopaedic surgery. The m ethodology that these fields utilize is applied in everyday practice. It is th erefore critically im portan t th at th e orth opaedic surgeon be fam iliar with th e tools an d m eth ods of biostatistics in order to critically evaluate available eviden ce surroun din g th e diagn osis an d treatm en t of orthopaedic populations and m usculoskeletal disease. Epidemiology is th e study of th e distribution an d risk factors for disease. Biostatistics is the application of statistical or m ath em atical m eth ods to th e collection , organ ization , and interpretation of clin ically relevant biological, m edical, or fun ction al data. Evidence-Based Medicine is th e practice of applyin g th e results of scien tific studies to th e practice of m edicine in general, and orthopaedic surgery in specific. Inference is th e derivation of logical con clusion s from existing knowledge regarding a specific condition . Biostatistical procedures allow in feren ces to be m ade with a quan tifiable certain ty. In feren ces are m ade regardin g probable causes and associations with disease, success of treatm ents, and factors th at m ay in fluen ce a specific con dition . Th is provides th e fram ework of epidem iological study.

DATA Data are a collection of facts from wh ich con clusion s m ay be drawn or derived. Data are used durin g patien t in ter-

views in order to m ake treatm en t decision s. Data can be used to decide wh at car to buy or, altern atively, wh ich specific treatm ent option is m ost appropriate. In the realm of biom edical study, data can be classified in to th ree types: continuous, ordinal, or categorical. The type of data that exists in a data set will in large part determ in e wh ich statisitical tests are appropriate for data analysis.

VARIABLES In form ation acquired for a given ch aracteristic of a un it of interest (m ost often a patien t in clinical studies) can be referred to as a “variable.” For example, in a study of patients with proxim al h um erus fractures, on e m ay be in terested in knowing the age of the patient, the gender of the patient, how m any “parts’’the fracture was, whether or not the patien t was a sm oker, wh at th e occupation of th e patien t was, and wh eth er or not the patient was treated operatively. Each defin ed param eter is gath ered an d th en recorded in a database for subsequen t an alysis. For th e above exam ple, suppose the variable of interest is tim e until union. Various statistical tests m ay be used to assess for an association between th e variable of in terest an d th e oth er variables in th e study, such as age of th e patien t or n um ber of “parts’’ in the fracture. Independent variables are variables that determ ine (or are though t to determ ine) the value of the dependent variable accordin g to th eir value. In an experim ental design, th e in depen den t variable of in terest is un der th e con trol of

30


the researcher (operative versus nonoperative treatm ent of proxim al h um erus fractures). Dependent variables are variables of in terest th at are th ough t to be affected in som e way by the independent variable(s) (e.g., tim e to un ion in the above example). Confounders are variables that m ay be related in som e way to both depen den t an d in depen den t variables an d, th erefore, m ay affect th e size of th e relation sh ip between th e depen den t an d in depen den t variable(s) (e.g., four-part proxim al h um erus fractures m ay be m ore likely to get surgery, but also m ay be m ore likely to h ave delayed or n on un ion ). In addition , oth er factors such as sm okin g an d increasing age m ay put patien ts at a higher risk for both the dependent variable (nonun ion) an d th e in depen den t variable (a fracture requirin g surgery).

TYPES OF DATA Data are organ ized by wh eth er th ey are strictly n um eric (con tin uous), ordered (ordin al), or categorical (qualitative). Continuous variables are n um eric values wh ere th e data can th eoretically take any value with in a ran ge of values. Num bers such as range of m otion, newton s of force, and temperature can be considered con tinuous. For comparing two differen t treatm ents or population s with continuous variables, the Studen t’s t test can be used for statistical analysis. For th ree or m ore groups with con tinuous variables, th e an alysis of varian ce (ANOVA) test can be used, an d for com parin g on e group to itself at a later date, the paired t test can be used. Ordinal variables are data that are represented in an ordered (valued) fash ion, but in wh ich th ere is n o specific scale by wh ich th e values differ. Th ese data are represen ted by in tegers (i.e., 1, 2, 3, . . . ). A prim e exam ple of ordin al data in orth opaedic surgery is the pain scale. Typically, nonparam etric tests are appropriate for statistical an alysis of th is type of data, as th ey are often n ot n orm ally distributed. Th e Man n –Wh itn ey U test is appropriate for two in depen den t groups, th e Kruskal– Wallis test is appropriate for m ore than two groups, and the Wilcoxin Sign ed-Ran k test is often appropriate for paired or test –retest data. Categorical (Nominal) variables are qualitative categories in wh ich th ere is n o specific value assign ed to th e data, but th e data differ in som e qualitative way. For exam ple, suppose on e wan ted to compare in jury rates in th e NBA, on e m ay break th e players down by position . Each position has no inherent value, but they differ from each oth er in som e qualitative way. A special type of categorical data is th e binary variable, a variable in wh ich a patien t eith er h as or doesn ’t h ave a certain ch aracteristic, for example, that patien t is either alive or dead, got treatm en t A or did n ot, an d played or did n ot play. Fish er’s exact test m ay be used to com pare two categorical groups, Pearson’s chi-square test m ay be used to compare two or m ore groups, an d McNem ar’s test can be used for paired variables.

DATA DISTRIBUTION Con tinuous data m ay be param etric or nonparam etric. Nonparametric data are data in wh ich th e distribution of the population values is n ot sim ilar to any specific standard distribution . Parametric, or distribution al, data can often be described by on e m ath em atical equation . Th ese equations assum e that the population from which the sample cam e is distributed sim ilar to a standard distribution. The m ost com m on distribution that data follows is a Gaussian, or “n orm al,’’ distribution . Th is distribution is bell sh aped an d is illustrated by Figure 2.1. Th e y axis ( f ( x)) represents the probability (or percen tage frequen cy) of observing a certain value. The x axis represen ts th e ran ge of poten tial values. Th e area un der th e curve is equal to 1 an d is the cum ulative probability of observin g any value un der th e curve. Th e m ean value is assum ed to be the apex of the curve. In a norm al distribution , 95% of values fall with in ± 2 standard deviations (SD) of the population m ean; this represents the 95% confidence interval. Furth erm ore, 69% of values fall with in ± 1 SD, an d 99% of values fall with in ± 3 SD. In a n orm al distribution, m ean, m edian, and m ode are all equivalen t. In gen eral, th e mean is th e sum of all observation s divided by the num ber of observations (the average). The median value is the 50th percentile value, or th e value under which h alf of th e observations occur. For n onparam etric data, m edian values are m ore robust because th ey are n ot in fluen ced by outliers (the skewness of th e data) to as great a degree. Th e mode is the m ost frequen tly observed value. Chi-square distribution an d th e bin om ial (logit fun ction ) distribution are other standard distributions used to m ake inferences about data. Skewness represen ts m ore data bein g clustered in low values of x or h igh values of x, in oth er words, an asym m etry in the data (Fig. 2.2). Kurtosis is wh en th e data are m ore or less peaked than norm al (m ore or less close to th e m ean). Statistical tests for skewness an d kurtosis are available in m ost com m ercially available statistical packages to determ ine whether or n ot param etric testin g is appropriate.

f(x)

µ

Figure 2.1 The normal distribution.

x

Chapter 2: Epidemiology and Biostatistics in Orthopaedic Surgery

31

Low Kurtosis

Right Skew Gaussian

Left Skew

Figure 2.2 Skewness and kurtosis.

INFERENCE Th e m ain purpose of biom edical research is to h elp us gain knowledge about th e truth or reality of a clin ical problem . Th is is th e purpose of in feren ce, a system atic usage of data to derive a broader con clusion . By usin g statistical m eth ods, we can draw con clusion s about population s on th e basis of a sam ple drawn from th at population . Our ability to do th is can be comprom ised by error. Systematic error is error that can be characterized by bias, confoun ding, or ch ance. Random error is error built in to m easurem en t tools due to im perfection of th e tool bein g used. System atic error can be m in im ized by rigorous study design and attention to detail. Ran dom error often can n ot be con trolled for un less a better test with m ore precise m easurem ents is available. Alternatively, random error (or chance) m ay be dim in ished by increasing the size of the sample studied so th at it m ore closely resem bles the entire population about which an inference is m ade. Our confiden ce in inference derived from statistical tests is m easured by a studies’ power and by the ability to reject th e null hypothesis.

ERRORS IN INFERENCE Bias is a n onrandom system atic error in the design or execution of a study th at m ay result in m istaken in feren ce about association of causation between th e independent an d dependent variables. There are a few com m on types of bias about wh ich every research er sh ould be aware. Selection bias involves situations in which two groups differ in som e significant way oth er than the independent variable of in terest. For exam ple, suppose a study was con ducted in which union rates were observed for two different treatm en ts of tibial fractures. Now suppose one group had m ore wom en an d th e oth er h ad m ore m en , th ere is selection bias between treatm en ts th at leads to a poten tial for confounding of th e effect of treatm en t m eth od on un ion rate by sex of th e patien t; th is bias m ay be m in im ized by ran dom ization or m atching con trols. Recall bias is com m on in retrospective studies, and it can occur wh en a patien t is asked to rem em ber qualities about h is or h er con dition at som e poin t in th e past. Th e patien t m ay n ot rem em ber h is or h er story perfectly. This bias m ay be m inim ized by controls, so that at

68% 1SD 95% 2SD

High Kurtosis

least bias is con sisten t, or by perform in g prospective studies in wh ich all pertin en t data are recorded as th ese occur. Measurement bias can be noted if an investigator asks question s, or records data, in such a way th at m ore accurate data are collected in on e treatm en t group (i.e., surgical) th an in an oth er group (i.e., n on surgical). Th is bias can be m in im ized by blin din g research ers to th e treatm en t type or by h avin g in depen den t reviewers. Sampling bias occurs wh en patien ts in th e sam ple are sign ifican tly differen t, in som e crucial ways, from the population in which the researcher is in terested in m akin g in feren ces. Th is m ay lead to a decrease in external validity or gen eralizability of results to population s outside th e study sam ple. Publication bias is noted wh en publish ed studies tend to h ave a greater effect size than all completed studies. Another type of publication bias is publication of on ly positive or sign ifican t results. Th is can be assessed for durin g m eta-an alysis usin g fun n el plots (Fig. 2.3). Missing data, or nonresponse bias, can lead to its own special types of ch allen ges. Most com m ercially available software packages deal with m issing data by listwise deletion. Th at is to say, if a patien t is m issin g any param eter, th en th at patien t is elim in ated for th e purposes of an alysis. If th e data are m issin g com pletely at ran dom , this m ethod of dealing with m issing data is probably the m ost robust an d does n ot in troduce addition al bias in to the study, but it does decrease power by m aking th e sam ple size sm aller. Essen tially, you are left with a subsam ple of th e origin al sam ple. Wh en th e data are n ot m issin g com pletely at ran dom , it is often n ecessary to employ a statistician to perform special tests on the data to determ in e the m ost appropriate way to deal with th e m issin g data. Confounders are variables that h ave an association with both th e in depen den t an d depen den t variables of a study. Variables such as age, gender, socioeconom ic status, m edical com orbidities, an d in jury severity are com m on examples of con foun ders. Suppose an in vestigator wan ts to determ in e wh eth er a cem en ted or cem en tless im plan t h as greater lon gevity. Th e research er would n eed to factor in by statistical adjustm ent, m atching, or random ization age and activity level; oth erwise, th e effect m ay be con foun ded by these factors (Table 2.1). When the study is retrospective, there sh ould be a dem ographic table that clearly evaluates poten tial con foun ders, an d if th ere is a differen ce, con sideration sh ould be m ade to statistically adjust for con foun din g

32

Orthopaedic Surgery: Principles of Diagnosis and Treatment 0.0

SE(log OR)

0.4

0.8

1.2

1.6

0.01

0.1

1

10

100 OR

Figure 2.3 An example of a funnel plot demonstrating publication bias.

by using suitable statistical m ethods (i.e., m ultivariate analysis, stratification , or m atch in g). Ran dom ized trials elim inate con foun ders if the sample sizes are adequate, but con founding variables should still be screen ed for potential confoundin g. Chance is the probability that two unrelated events will seem related by random occurren ce or vice versa. Chan ce can take two form s. Type I error is th e conclusion that a true association between variables exist wh en in reality th ere is no difference. Type II error is th e probability of failing to fin d an association wh en on e actually exists (Table 2.2). If m ultiple comparison s are bein g perform ed, it is importan t to adjust for m ultiple tests in order to n ot in flate th e type I error.

METHODS FOR CONTROLLING SELECTION BIAS Selection bias can be con trolled in th e design or an alysis ph ase of th e study. In th e design ph ase, selection bias can

TABLE 2.2

TABLE 2.1

THE RELATIONSHIP BETWEEN TYPE I AND TYPE II ERROR

AGE AND GENDER BY IMPLANT TYPE Factor Age Gender (% female)

be con trolled by ran dom ization , restriction , or m atch in g. Randomization in volves th e ran dom assign m en t of patien ts into each arm of the study; with appropriate design, each patien t h as an equal ch an ce of bein g in each arm of th e study. Restriction in volves lim itin g wh ich patien ts are eligible for the study (i.e., inclusion an d exclusion criteria). Matching involves inten tion ally selecting patients who are sim ilar to one an other in each known confounder, but who are different in the outcom e of in terest in order to determ ine important associated risk factors for that given outcom e (i.e., case-control study design). In th e an alysis ph ase of th e study, stratification , sim ple adjustm en t, or m ultivariate tech n iques can be used to adjust for con foun ders. Stratification in volves comparing subgroups of patients; for example, comparing operative versus non operative fracture care, one m ay opt to stratify by severity. Simple adjustment involves adjusting effect m easures for strata of patients by som e con founder. Multivariate analysis allows for adjustm ent by m ultiple factors at on ce.

Cemented

Uncemented

P value

67 56

66 54

.48 .45

Example of potential confounders in which there is no evidence of association between independent factors that are also associated with the outcome of interest (longevity of implant).

True association No association

Study Shows Association

Study Shows No Association

Study is accurate ( p = 1 – α) Type I error ( p = α)

Type II error ( p = β ) Study is accurate (p = 1 – β)


A WORD ABOUT CAUSALITY Most often in epidem iological studies, we observe associations not causes. For causality to be assigned, a num ber of factors, first described by Sir Bradford Hill, m ust be satisfied. 1. Temporality: Cause precedes effect 2. Strength: Large effect size (relative risk, odds ratio, h azard ratio) 3. Dose response: Larger dose, h igher/ m ore likely effect 4. Reversibility: Reduction in exposure associated with decreased disease 5. Consistency: Repeatedly observed by differen t research ers in tim e an d space 6. Biologic plausibility: Reasonable based on curren t knowledge 7. Specificity: One cause, one effect 8. Analogy: Sim ilar cause an d effect exist for a sim ilar disease/ exposure pair O ften we do n ot observe causality but we do recogn ize associations.

STUDY DESIGN AND EVIDENCE-BASED MEDICINE Overview Eviden ce-based m edicin e is th e con scien tious usage of th e m ost convincing literature to m ake decisions in the care of in dividual patien ts. Th e best in form ation is attain ed through epidem iologic and scientific studies from which inferences are m ade. The m ore rigorous the design and the

33

m ore diligen t th e con trol of error, th e m ore m ean in gful a specific study is. An outline of the levels of evidence is presen ted Table 2.3.

Observational Versus Experimental Studies Th e m ore th orough on e is in con trollin g for con foun din g and bias, the m ore con fident one can be in drawing conclusion s an d m akin g in feren ces about th e gen eral population. Broadly, research can be divided in to observation al and experim ental research . Th e m ajority of orthopaedic research is observation al. Descriptive observational studies include case reports, case series, and cross-section al studies; th ese studies are easy to perform but som ewhat vulnerable to bias due to lack of con trols. Case studies are reports of in dividual patien t treatm en t an d outcom es. Case series are a num ber of patients (> 1) wh o h ad sim ilar treatm ent but with out con trols with wh om to compare th em . Crosssectional studies are a snapshot in tim e th at can determ in e wh at th e prevalen ce of a disease is an d th e dem ograph ic or person al m edical ch aracteristics of patien ts wh o ten d to presen t with a disease th ey h ave. Th ese studies are un able to dem on strate causality; h owever, th ese can sh ow stron g associations and can often lay the groundwork for m ore soph isticated prospective or experim ental designs. Analytic observational studies are often retrospective but can provide useful in form ation regardin g association s predictive of an outcom e of in terest. Case-control studies are studies in wh ich cases are chosen by outcom e, an d a sim ilar set of controls without that outcom e are chosen to determ in e if th ere are certain factors th at are associated with the disease. In case-control studies, cases are chosen by depen den t variable (failure of fixation , success, or disease of in terest), so th is type of design is particularly useful an d

TABLE 2.3

LEVELS OF EVIDENCE Level

Therapeutic

Prognostic

Diagnostic

I

High-quality RCT, narrow confidence intervals, > 80% follow-up

II

Lesser-quality RCT < 80% follow-up, no blinding, improper randomization, etc.

Testing of previously developed diagnostic criteria with consecutive patients with gold standard reference Development of diagnostic criteria on consecutive patients with universally applied gold standard

III

Case-control study, retrospective comparative study Case series Expert opinion

High-quality prospective study where all patients enrolled at same point in disease, 80% follow-up Retrospective study, untreated controls from an RCT, lesser-quality prospective study (e.g., patients enrolled at different points in their disease, < 80% follow-up) Case-control study

IV V

Case series Expert opinion

Study of nonconsecutive patients without gold standard Case-control study Expert opinion

RCT, randomized clinical trials A systematic review of any level of evidence is equal to that level of evidence. Data from Clinical Orthopaedics and Related Research (http://www.clinorthop.org/library/Downloads/levels oe.doc).

34


efficien t wh en th e disease of in terest is rare. Cohort studies are studies in wh ich th e groups are ch osen by th e exposure or treatm en t an d subsequen tly followed to observe an outcom e of interest. These studies m ay be prospective or retrospective. In coh ort studies, exposure is m on itored, an d then patients are followed for outcom e, so they are useful in cases wh ere th e exposure is rare or of particular in terest to th e research er. In th is m an n er, exposure m ay be assessed statistically to determ in e th e risk of subsequent disease or outcom e developm en t. Meta-analysis is used wh en there are a num ber of sim ilar studies describing the sam e ph en om en on , or an alyzin g th e sam e treatm en t, disease, or outcom e, but each in dividual study is of in sufficien t power to stan d alon e. Meta-an alysis m ay also be used to an alyze the state of curren t knowledge, or to trace changes in practice over tim e. An alytic observation al studies are useful because there is no preset allocation of treatm ent groups, they are often easier an d ch eaper to perform th an prospective studies, and, if done properly, can m ake inferen ces about causality. These studies can also provide backgroun d inform ation for design in g experim en tal or future prospective observation al studies. Observational studies can be prospective or retrospective depen din g on th e lin e of in quiry. In retrospective studies, th e in quiry begin s with th e outcom e of in terest an d attempts to elucidate a risk factor or exposure th at m ay be associated with th at outcom e. Prospective studies begin typically with th e exposure of in terest an d follow patien ts over tim e to determ in e outcom es. It sh ould be n oted that a study that starts with an exposure or treatm ent m ay be retrospective if patien ts with th at treatm en t in th e past are reviewed for outcom es th at are already docum en ted (Fig. 2.4) Th e prim e example of an experimental study is the randomized clinical trial. Th ese studies are ideal for evaluatin g treatm en t efficacy but ten d to be expen sive an d tim e an d labor in ten sive.

Retrospective

Prospective study onset

Exposure

Outcome

Cases

Cohort

INQUIRY

Exposure

Outcome

study onset

Figure 2.4 Direction of inquiry for prospective and retrospective studies.

DESCRIPTION OF STUDY TYPES A case series is a retrospective observational descriptive accoun t of a group of patien ts with an in terestin g treatm en t, con dition , or con stellation of sym ptom s. Th ese studies are typically useful for hypothesis generation, or to show feasibility or safety of a treatm ent. A new technique can be described with outcom es of th at tech n ique. Th is type of study typically m ay provide the fram ework for m ore soph isticated studies. An example of this type of study was John Charnley’s description of th e usage of m ethyl m ethacrylate cem en t for securin g com pon en ts in total h ip arth roplasty. Th is paper h elped con vin ce surgeon s of its utility, safety, and effectiveness. Case series are inexpensive, useful to describe n ovel treatm ents and complication rates, and provide backgroun d data for future studies. However, because n o con trol group exists, th ey are vuln erable to con foun din g and bias. Inferences that can be drawn are lim ited because there is n o hypothesis being tested. Case series provide level IV eviden ce. A cross-sectional study is an observation al/descriptive tech n ique th at is essen tially a “sn apsh ot’’in tim e of a population . On e m ay ascertain th e distribution of an outcom e or risk factor in a population . Population -based n orm ative data can also be gen erated usin g cross-section al studies. Th ese studies are quick, data th at m ay be extrapolated to a larger population can be gain ed, an d association s m ay be observed. In addition , baselin e in form ation on dem ograph ics, n orm ative ch aracteristics, or baselin e disease data can be collected. A cross-sectional study can provide inform ation on prevalence of a disease, but n ot on incidence. Prevalen ce is equal to th e total n um ber of cases at a tim e divided by th e total population at risk, wh ereas in ciden ce is equal to the num ber of new cases th at develop divided by the population or sample at risk over that tim e period. Sam plin g error m ay lim it th e extern al validity of th ese studies. Cross-section al studies are typically level IV evidence of dem ography, epidem iology, or n orm ative values to be used for power calculation s, or as baselin e data preferably in prospectively designed studies. A case-control study is a retrospective observation al/ an alytical study in wh ich patien ts with a given outcom e (cases) are compared with patients who lack that outcom e (controls), to determ in e association s with the outcom e of in terest. The outcom es of interest are typically rare, and results are often reported as an odds ratio, or th e odds of a case bein g exposed compared to th e odds of a con trol bein g exposed to th e sam e factor. For exam ple, suppose we wan ted to com pare patien ts with n on un ion s to patien ts with un ited fractures for exposure to n on steroidal an ti-in flam m atory drugs (NSAIDs). Th is could be don e through a case-control design. The case-control m odel is efficien t for rare outcom es an d is in expen sive. Weakn esses of th is m odel in clude difficulty in fin din g appropriate con trols an d in com plete m edical records. Con trols sh ould be m atch ed, or m ultivariate an alysis sh ould be con ducted to


adjust for confounding. Significant bias in the form of recall, reporting, or sampling bias can exist. These studies are typically level III or IV eviden ce depending on the sophistication of the study design an d analysis. Prospective cohorts are observation al an alytical studies that follow a population with a specific exposure or treatm ent over tim e to iden tify outcom es of interest. The Fram in gh am Heart study is on e of th e m ore fam ous coh ort studies that investigated the risk factors for heart disease. Coh orts can estim ate disease incidence, evaluate a disease’s course or natural history, and identify risk factors. The cohort study has th e ability to identify n ested case-control studies within the cohort (i.e., an in terim outcom e is iden tified and studied). The power of the study increases with increasing disease frequen cy (num ber of patients with the outcom e of in terest). Coh orts are h owever expen sive an d labor intensive, often require m ultiyear gran ts and a com preh en sive data collection system , an d are susceptible to bias, error, con foun din g, an d loss of follow-up. Typically, the effect m easure is reported as a relative risk, that is, th e risk of an exposed in dividual to develop th e disease com pared with th e risk of th e un exposed in dividual to develop the disease. Typically, prospective cohorts are level II to III eviden ce depen din g on soph istication , data collection m ethod, and rate of follow-up. Randomized clinical trials (RCTs) are experim en tal studies that involve usage of con curren t (RCT), sequential (crossover), or historical controls. Th e gold standard RCT is th e random ized double-blind, placebo-controlled trial. RCTs require a protocol that establishes eligibility (in clusion an d exclusion criteria), sam ple size (a power an alysis), ran dom ization (to m inim ize bias and con foun ders), blin din g (to m in im ize perform an ce, detection , an d in terviewer bias), stopping rules, m onitoring for compliance, safety assessm ent, an d in ten tion to treat analysis to m in im ize nonresponder bias. Alth ough th ese studies are th e gold standard of biom edical research, these are extrem ely expen sive an d logistically difficult. Eth ically, th ese studies require the optim al treatm ent to be truly unknown. The level of evidence is I or II dependin g on th e above listed factors, type of ran dom ization , an d patien t reten tion (> 90% for level I). Random ized clin ical trials have excellent intern al validity, because th e result occurred un der ideal experim en tal con dition s. It is also im portan t to n ote th at if inclusion and exclusion criteria are too stringen t, a clin ical trial m ay have very poor external validity (m ay be poorly gen eralizable to th e population as a wh ole). In addition to observation al an d experim en tal studies, reviews are an oth er form of research . Expert opin ion is level V evidence, but it is a form of review based on expert experien ce. Systematic reviews (level IIa an d IIIa) are an eviden ce-based sum m ary of th e literature th at uses a com plete search an d critical an alysis of th e study. If th e studies involved are level III eviden ce, then the system atic review is also level III. Meta-analysis is th e process by wh ich qualitative m eth ods are applied to compile th e results of several

35

in depen den t studies to produce sum m ary statistics. A true m eta-an alysis con tain s on ly th ose studies th at are h om ogeneous with respect to inclusive criteria and outcom es of in terest. Forest plots can sh ow th e sum m ary effects of data collected from m ultiple studies. Q tests can be used to assess for heterogeneity of studies in clinical treatm ent, m ethodology, or m easured effect. Lastly, publication bias sh ould be in vestigated. Fun n el plots are useful to detect gen eral publication bias; oth er special tests can be used to detect publication bias by date or geograph ic location .

HYPOTHESIS TESTING Th e classic approach to determ in e statistical significance is to compare observed findings with expected findin gs. This com parison allows on e to determ in e if an outcom e could h ave occurred sim ply by ch an ce. Th e comparison between treatm ents or between a risk factor and an outcom e typically takes on th e n ull hypoth esis th at th ere is n o differen ce between treatm en ts or th ere is n o association between a risk factor (in depen den t variable) an d a con dition (depen den t variable). Th e altern ative hypothesis states that there is a true difference between the groups. Type I error exists if on e finds no difference/association when th ere truly is one, an d a type II error exists if one finds a differen ce where n on e exists (Table 2.2). Wh ere m ultiple hypotheses exist, one m ust adjust the type I error to account for that num ber of m ultiple tests, oth erwise the type I error will cum ulatively increase with increasin g num bers of hypoth eses. P values are th e probability of an even t occurrin g by chance alone; these values are th e result of th e statistical test th at is perform ed. Th e p value is a m easure of the stren gth of th e eviden ce in favor of th e null hypothesis. If p > α, th en th e n ull hypoth esis m ay be rejected. P values do not provide units, are not a m easure of the strength of an association, and there is little inherent precision to a p value. Sim ilarly, the p value does n ot con vey practical sign ifican ce but rath er an observed probability based on th e sample studied. Confidence intervals are con structed around a m ean, an d if the result is statistically significant, th e in tervals do n ot overlap or, in th e case of odds ratios, do not in clude on e. Th ese con fiden ce in tervals are based on th e alph a levels determ in ed at study on set. Th ese values are m ore precise than p values because these provide a range of values. Alpha is th e probability of con cluding that two th in gs are differen t wh en in fact th ey are n ot. Th e lower th e α, the m ore rigorous the criteria are for rejecting the null hypoth esis, an d th e less likely a research er is to con clude th at th ere is a differen ce wh en th at differen ce was th e result of chance alone. The m ost com m on α is 0.05; at th at level, th e probability of m akin g a type I error (con cludin g th ere is a differen ce when th ere is n one is 1 in 20). β is th e probability of m aking a type II error, that is, concluding there is no difference wh en in fact there is. Power is 1 –β . Wh en a study dem onstrates that there is a significant difference,

36


TABLE 2.4

STATISTICAL TESTS AND SETTINGS OF USE Type of Data Continuous normal Continuous not normal Continuous normal Continuous not normal Ordinal Ordinal Nominal Nominal Survival

Number of Groups 2 2 >2 >2 2 >2 2 >2 2/> 2

Independent

Paired

Student’s t test Mann–Whitney U test ANOVA Kruskal–Wallis test Mann–Whitney U test Kruskal–Wallis test Fisher test Pearson chi square Log-rank statistic

Paired t test Wilcoxin signed rank test Repeated-measures ANOVA Friedman test Wilcoxin signed rank test Friedman test McNemar test Cochran Q test Conditional logistic regression

ANOVA, analysis of variance.

there is a potential to m ake a type I error, and when there is n o differen ce, th ere is a possibility of m akin g a type II error. Th at possibility is in creased if th e study is un derpowered, an d so if a study sh ows n o differen ce, a power an alysis sh ould be reported. Statistical tests are ways of determ inin g the probability of m aking a type I error (Table 2.4). Specific statistical tests can be used to m easure association or differen ce. Th e followin g tests determ in e th e sign ifican ce of a differen ce: ■ ■ ■ ■ ■

Ch i-square ( X2 ) test compares observed versus expected proportion s. Fish er’s exact test compares proportion s for a sm all n um ber of observation s (wh ere th ere is a cell with < 5). Man n -Wh itn ey U test compares m edian values. Studen t’s t test compares m ean values. ANOVA compares two or m ore m ean s.

Th e followin g tests are used to describe or m easure agreem en t: ■ ■ ■

Regression coefficien t: Association between an independen t an d depen den t variable; Pearson’s r : Association between two variables; and Coh en ’s kappa: A m easure of agreem en t between or with in observers, values ran ge from 0 (completely ch an ce) to 1 (perfect agreem en t).

Power analysis is essential to determ ine how m any patients are necessary to detect th e difference a research er is in terested in. If the researcher sets the difference at th e m inim um clinically important difference, if n o difference is detected, it is safe to say that th ere is n o clinically importan t differen ce between groups. Th e elem en ts of a power analysis are the type I error rate that is acceptable, the type II error rate th at is acceptable, th e varian ce of th e expected m ean, the sample size, and an entity called the delta (effect size). Delta is the m inim um detectable chan ge. In m any cases, th e varian ce will be un kn own , an d an effect size is estim ated on th e basis of wh at th e research er con siders to

be clin ically im portan t. In gen eral, post h oc power an alysis sh ould be avoided, because at th e en d of th e study, the power has already been determ in ed by the num ber of patien ts en rolled. Clinical significance is distin ct from statistical sign ificance. A study can find a statistically significant result, but the m agnitude of difference, or th e param eter studied, m ay n ot m atter practically or clin ically. If a study h as a large sam ple size, a statistical differen ce m ay be detected, but th at differen ce m ay not be clinically important. For example, suppose two tech n iques for m easurin g leg len gth s followin g total h ip arth roplasty are available, an d th e two m eth ods differ by 0.1 m m , but because of th e n um ber of patien ts or precision of in strum en ts, th e statistical differen ce is foun d to h ave a p value of .001. It could be said that the differen ce between these two m ethods is h ighly statistically significant but do not dem onstrate clinically important differen ces.

Measures of Effect Other tests are used to give inform ation about the association between variables. Unadjusted tests include probability, odds, odds ratio, relative risk, and hazard ratio. Probability takes the form of a value between 0 and 1 an d represen ts th e likelih ood of an even t h appen in g on th e basis of the n um ber of events over th e num ber of trials; for exam ple, tossin g a coin sh ould h ave a probability of 0.5. Odds are th e probability of observin g an even t in a trial over the probability of not observin g th at event; for a coin toss, odds would be equal to 0.5/ 0.5 or 1. Th e odds ratio represents the odds of exposure to a risk factor between a case group an d a con trol group. Th e relative risk represen ts th e inciden ce of disease in an exposed population over the in cidence of disease in an unexposed population. The hazard ratio compares two groups in term s of th e risk of an event occurrin g in a particular period of tim e. Hazard ratios can be calculated with Kaplan –Meier survival an alysis. Many

37


TABLE 2.5

1.0

UNIVARIATE AND MULTIVARIATE ANALYSIS Univariate

Multivariate

Continuous Binary Time series

Pearson’s r Odds ratio Hazard ratio (Kaplan Meier)

Linear regression Logistic regression Cox regression

0.8 Sensitivity

Outcome

0.6

0.4

of th e m easures of association or effect m easures can be adjusted to take into account m ultiple confounders. This process is called multivariate analysis (Table 2.5). Multivariate analysis often involves complicated procedures and post h oc an alysis, an d perform an ce of th ese tests sh ould involve som eone fam iliar with their execution.

0.2

0.0 0.0

0.2

A

0.4

0.6

0.8

10

0.8

10

1 - Specificity

TEST CHARACTERISTICS 1.0

0.8 Sensitivity

Often tim es in m edicine, it is beneficial to develop a test to diagn ose a con dition . Wh en developin g such a test it is often com pared to a “gold stan dard.’’ Gold stan dard tests typically have excellent ability to diagnose condition s but are often expen sive, in vasive, or otherwise inconven ient; for example, the gold stan dard for diagnosing m eniscus tears is arth roscopy, but arth roscopy is in vasive an d is n ot always indicated. It is therefore desirable to find an alternative test. These alternative tests are often compared to the gold standard for sensitivity, specificity, positive predictive value, and negative predictive value. Sensitivity is the ability of a test to detect a condition when it is present; thus, m ath em atically, it is th e n um ber of true positives over th e num ber of true positives plus false negatives (or all positive tests). Specificity is the ability of a test to not falsely assign a well person as sick; thus, m athem atically, it is the num ber of true n egatives over all n egative tests (true n egatives plus false positives). Positive predictive value is th e probability of h avin g th e disease with a positive test; it is th erefore represen ted by true positives over all positive tests. Negative predictive value is th e probability of n ot h avin g th e disease with a n egative test, an d it is th erefore equal to true n egatives over all n egative tests. Sen sitivity an d specificity are often a trade off; for example, suppose th e fastin g level of blood sugar n ecessary to diagn ose diabetes was dropped to 80, then th e sensitivity would be nearly 100%, we would diagn ose 100% of diabetes, but we would falsely diagn ose m ore patien ts; th us, th e specificity would drop th is paradox an d can be represen ted graph ically with a receiver operator curve (Fig. 2.5). An example of this is where it is desirable to figure out h ow m any wh ite blood cells in a total join t con stitute an infection. If the cutoff is too low, too m any people will h ave n eedless surgery; if it is too h igh , too m any in fection s will be m issed. In addition , it is im portan t to n ote th at positive predictive value will be low if th e prevalen ce is low

0.6

0.4

0.2

0.0 0.0

B

0.2

0.4

0.6

1 - Specificity

Figure 2.5 Reciever operating curves for predicting peripros-

thetic infection. An area under the curve of 1 demonstrates an ideal test with a 100% sensitivity and specificity, whereas an area under the curve of less than 0.5 indicates that the diagnostic has poor discriminatory value. (A) The cutoff value for optimal accuracy in diagnosis of PJI was 1100 cells/L for fluid leukocyte count. (B) The cutoff value for optimal accuracy for fluid neutrophil differential was 64%. When both tests yielded results below their cutoff values, the negative predictive value of the combination increased to 99.6%, whereas if both tests were greater than their cutoff values the positive predictive value improved to 100%. (Redrawn with permission from Parvizi J, Ghanem E, Sharkey P, Aggarwal A, Burnett SJ, Barrack RL. Diagnosis of infected total knee: findings of a multicenter database. Clin Orthop Relat Res. 2008;466(11):2628–2633.)

even if sen sitivity an d specificity are h igh , because it is likely th at any positive will be a false positive. Th is is th e ration ale beh in d selective screen in g. Suppose, we wan ted to screen everyon e for lun g can cer with a ch est x-ray. Th e prevalen ce of lun g can cer in th e gen eral population is relatively low,

38


so any positive result would likely be a false positive. If we restrict th e screen in g tool to sm okers with h em optysis, th e predictive value would get m uch h igh er because th e prevalen ce in th at population would be h igh er.

HEALTH OUTCOMES RESEARCH Th e Am erican Academy of Orth opaedic Surgeon s an d oth er organ ization s h ave created musculoskeletal outcomes instruments to collect stan dardized patien t data to assess an d compare treatm en t m odalities an d regim en s. Th ese in strum en ts h ave been validated, an d m any h ave n orm ative scores available for th e purposes of power an alysis an d comparison. Examples of such scores include th e Hip Society Score, th e Kn ee Society Score, th e DASH, Pediatric O utcom es Data Collection Instrum ent, an d the ASES (Am erican Sh oulder an d Elbow Surgeon s) subjective sh oulder scale. General health outcome instrum ents m easure general h ealth an d well-bein g, th e m ost com m on is th e SF-36.

Visual analog scales can be used to m easure patient satisfaction , pain , an d gen eral outcom e.

RECOMMENDED READINGS Abel U, Koch A. Th e role of ran dom ization in clin ical studies: m yth s and beliefs. J Clin Epidemiol. 1999;52;487 –489. Ben son K, Hartz AJ. A com parison of observation al studies and random ized con trolled trials. N Engl J Med. 2000;342:1878 –1886. Bern stein J, McGuire K, Freedm an KB. Statistical sam pling and hypoth esis testing in orthopaedic research. Clin Orthop Relat Res. 2003;413:55 –62. Bern stein J. Eviden ce-based m edicin e. J Am Acad Orthop Surg. 2004; 12(2):80 –88. Freedm an KB, Back S, Bern stein J. Sam ple size an d statistical power of ran dom ized con trolled trials in orth opaedics. J Bone Joint Surg Br. 2001;83(3):397 –402. Hun sacker FG, Cioffi DA, Am adio PC, Wrigh t JG, Caugh lin B. The Am erican Academy of Orthopaedic Surgeon s outcom es instrum ents: norm ative values from the gen eral population. J Bone Joint Surg Am. 2002;84(2):208 –215. Kocher MS, Zurakowski D. Clinical epidem iology and biostatistic: a prim er for orthopaedic surgeons. J Bone Joint Surg Am. 2004; 86-A(3):607 –620.

Im aging in Orthopaedic Surgery Tu rn er Vosseller

3

John N. Delahay

Th is ch apter will offer a brief in troduction in to th e m ajor im agin g m odalities used in orth opaedic surgery. Th e m ost basic m edium of im aging rem ains plain radiography, wh ich can provide a wealth of in form ation quickly for relatively little cost. In the past 30 years, the im aging repertoire available to the orthopaedic surgeon has expan ded greatly, with th e adven t an d widespread availability of computed tom ography (CT) scan s an d m agn etic reson an ce im agin g (MRI). Ultrasonography, nuclear scintigraphy, an d bone den sitom etry are also com m on ly used in th e evaluation of m usculoskeletal disease. Finally, a brief discussion of safety an d radiation exposure to the orthopaedic surgeon is in cluded.

PLAIN RADIOGRAPHY As stated above, plain radiography is th e m ost com m only used im agin g test in th e evaluation of orth opaedic traum a an d m usculoskeletal pain . It gives excellent visualization of the osseous anatomy as well as som e in direct inform ation about the surrounding soft tissues. Because of their ease of acquisition and low cost, plain x-rays are alm ost always the first step in th e im agin g workup, an d diagn ostic errors can occur wh en th ey are om itted. When evaluatin g plain x-rays, it is importan t to rem em ber th at th e im age is a two-dim en sion al represen tation of a three-dim ensional structure. On a single x-ray view, displacem en t of a fracture in on ly two out of th e th ree possible plan es of displacem en t is visualized. For exam ple, an an teroposterior (AP) view of th e wrist dem on strates displacem en t in the m edial lateral plane and the superior–in ferior plan e but does n ot provide any in form ation regardin g dis-

placem en t in th e AP plan e. In order to evaluate displacem en t in th e AP plan e, a secon d film th at is orth ogon al to th e first m ust be obtain ed. A lateral view of th e wrist will dem on strate the AP displacem en t as well as superior– in ferior displacem en t. For the distal joints an d extrem ities, obtaining the two orth ogon al views is easily accom plish ed by rotatin g eith er the extrem ity or the x-ray beam 90 degrees. For th e m ore proxim al join ts, such as th e h ip an d sh oulder, th is is n ot possible, so special radiograph ic views h ave been developed to provide th e n ecessary in form ation . In addition to these views, a num ber of special techniques have been developed to better visualize structures th at are n ot well seen on routin e AP an d lateral radiograph s. Th e followin g section s con tain a description of m any of th ese special views used in th e evaluation of each of th e m ajor an atom ic region s of th e body. Illustration s of m any of th e tech n iques described, as well as exam ple radiograph s, are con tain ed in the later ch apters in this book that cover the orthopaedic subspecialties. The reader is also encouraged to seek out oth er texts th at are dedicated specifically to orth opaedic im agin g for m ore detailed description s of radiograph ic positionin g an d techn iques.

Cervical Spine Th e routin e traum a series of th e cervical spin e in cludes a lateral view, an AP view, and an open mouth odontiod view. Th e lateral view is improved by pullin g down on th e patient’s arm s; traction should never be placed on th e head. A swimmer’s view m ay be necessary if the en tire cervical spin e down to th e C7-T1 disk space is not visualized on th e lateral view. This view is obtained with one of the patient’s

40


arm s raised an d th e oth er at th e patien t’s side. Soft-tissue swelling can be in dicative of injury in the absence of obvious bony deform ity. Th e gen eral rule is 6 m m of soft-tissue swelling at C2 and 22 m m of soft-tissue swelling at C6 is in dicative of path ology. The utility of traum a oblique views, perform ed with th e patien t supin e, is arguable, an d th ey are n ot routin ely obtain ed to “clear’’th e cervical spin e. Th ey m ay be effective in high-risk settings, in wh ich a better evaluation of the articular pillars an d th e C2 segm en t can be m ade. Oblique views are m ost useful if a traum a table with an articulated C-arm is available, or if th ey are don e uprigh t, wh ich is possible on ly in low-risk cases. Lateral views of th e cervical spin e in flexion an d exten sion are of very lim ited utility in traum a. Th ey m ay provide added con fiden ce in clearin g low-risk cases, particularly when equivocal fin dings are n oted on th e prelim inary evaluation or wh en patien ts report pain th at is out of proportion with n orm al x-ray fin din gs. Flexion an d exten sion views are contraindicated when th e patient’s level of con sciousn ess is altered. In cases in wh ich th e clin ical suspicion of instability or ligam entous laxity is high, MRI is a better an d safer test th an flexion an d exten sion radiographs. The pillar view is an AP projection taken with the x-ray tube an gled approxim ately 25 ◦ in a caudal direction. Th is view better visualizes th e articular pillars an d lam ina of the lower cervical spine, which are at particular risk in hyperexten sion / compression in juries. A pillar view m ay be useful wh en th e stan dard AP view suggests possible m alalign m en t of th e pillars. With th e in creasin g availability, speed, an d utility of CT evaluation in traum atized patien ts, th e th resh old to perform CT should be low in high-risk patients, particularly if

routin e radiograph s are suboptim al or suspicious, an d th e patien t is already goin g to CT for evaluation of th e h ead or body.

Shoulder Atrue AP of th e sh oulder (Grash ey view) takes in to accoun t the fact that the coronal plane of the glenoh um eral joint is an gled about 40 ◦ m edially to the coronal plane of th e body (Fig. 3.1). Th erefore, th e x-ray beam is angled about 40 ◦ m edially so th at it is perpen dicular to th e glen oh um eral join t line (Fig. 3.2). Often the evaluation of the shoulder not

45˚

A

B Figure 3.1 A true anteroposterior (AP) of the shoulder show-

ing an anteroinferior glenoid fracture. Note the visualization of the glenohumeral joint space afforded by this view. (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown C, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Figure 3.2 A. The true AP view of glenohumeral joint requires

the beam to be angled 45 degrees from the sagittal plane. B. True AP view shows the joint in profile and the tuberosities are outlined. (Reprinted with permission from Bucholz RW, Heckman JD, CourtBrown C, et al. Rockwood and Green’s Fractures in Adults, 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Chapter 3: Imaging in Orthopaedic Surgery

A

41

B Figure 3.3 Technique for obtaining a scapula lateral, also known as the ”Y-view, x-ray.” With the

cassette placed on the lateral aspect of the shoulder (A), the x-ray beam is directed parallel to the plane of the scapula (B). (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown C, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

initiated by th e orthopaedic surgeon begins with an “AP’’ of th e sh oulder in in tern al an d extern al rotation . In fact, th is AP is an anteroposterior view of the ch est, not a true AP of the shoulder. While these views can be useful to visualize calcifications with in the tendons of the rotator cuff, they provide little in form ation about th e glen oh um eral join t as there is overlap of the hum eral head on the glen oid. Th e axillary view is orth ogon al to th e true AP an d evaluates th e glen oh um eral join t an d th e relative position s of the hum eral head and th e glenoid fossa in the axial plane. Th is x-ray is perform ed with th e arm fully abducted an d the x-ray beam aim ed at the axilla. This view is especially helpful in th e evaluation of the dislocated shoulder an d m ust be obtained to confirm reduction. Often, it is difficult to get the patient to abduct sufficiently to obtain an axillary lateral view due to pain. In this setting, a Velpeau axillary view can be obtained with the patient leaning backward over the cassette and the x-ray shot from superior to inferior. Alon g with the true AP and the axillary lateral, the third view that completes th e routine evaluation of th e sh oulder is the tran sscapular or scapular Y view (Fig. 3.3). Th is view can act as an adjuvan t to th e axillary lateral view to furth er assess an terior or posterior displacem en t of th e hum eral head in the setting of dislocation . The hum eral head should be visualized within the glenoid fossa between the coracoid process anteriorly an d the scapular spine posteriorly. Am odification of th e axillary view is th e West Point view, wh ich improves detection of an an teroin ferior glen oid rim fracture after dislocation . The patient is positioned prone with th e arm abducted 90 ◦ and th e cen tral ray angled 20 ◦ to 30 ◦ ceph alad an d 25 ◦ to 30 ◦ m edially. Th e Stryker or “notch’’ view is used to visualize Hill-Sachs defects in the h um eral head. It is obtained with the patient supin e, th e

arm flexed, an d th e palm placed on top of th e h ead with the central ray directed 10 ◦ cephalad (Fig. 3.4). Zanca (or apical oblique) an d serendipity views im age th e lateral an d m edial clavicle, respectively, with 10 ◦ to 40 ◦ of ceph alic tilt (Fig. 3.5).

Hand and Wrist Th e routin e wrist series con sists of postero–anterior ( PA) , lateral, and oblique views. Traction x-rays can be useful in distal radial fractures to better define fracture anatomy, especially in in tra-articular fractures. Th e lateral view is

Figure 3.4 A fracture of the base of the coracoid is best seen

on a Stryker notch view. (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown C, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

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A

B Figure 3.5 A true anteroposterior (AP) radiograph (A) commonly obscures the fracture pattern. An apical oblique view (B) is helpful to better demonstrate the fracture pattern. (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown C, et al. Rockwood and Green’s Fractures in Adults, 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

used to evaluate for dislocation , m alalign m en t, or in tercalated segm ent in stability. The adequacy of the lateral view can be evaluated by lookin g for th e distal pole of the scaphoid to be in line with the hook of the ham ate. A lateral view with th e wrist angulated approxim ately 20 ◦ off th e cassette allows for a look at th e radiocarpal join t space, taking into accoun t the radial inclin ation . Specific views of th e scaph oid sh ould be obtain ed in th e settin g of traum a. Th is view is don e in th e PA projection , with th e wrist ulnarly deviated an d with slight ceph alad angulation of th e beam , wh ich elon gates th e waist of th e scaph oid. However, one m ust keep in m ind that a scaph oid fracture can have norm al radiographs initially. A clenched fist view can be used to evaluate for scapholunate widenin g and is typically don e in supin ation with uln ar deviation . Views of the opposite side can be obtained for comparison. A carpal tunnel view, obtain ed by hyperexten din g th e h an d an d di-

rectin g th e beam 30 ◦ above the horizontal axis is used to visualize the hook of the ham ate an d th e pisiform .

Pelvis and Hip Th e standard AP view of th e pelvis is taken with th e patien t supin e an d th e feet in tern ally rotated approxim ately 15 ◦ in order to get a true coronal view of the fem oral necks. Th e in tern al rotation is n ecessary to coun teract th e 15 ◦ of an teversion presen t in th e fem oral n eck. In th e settin g of acetabular fracture, Judet views are obtained. Th ese x-rays are 45 ◦ oblique views of th e pelvis. Th e obturator oblique sh ows the anterior colum n and th e posterior rim of the acetabulum an d can be iden tified by th e O of th e obturator foram en on the x-ray (Fig. 3.6). The “Spur sign’’ seen on the obturator oblique is pathognom on ic of a both colum n acetabular fracture. Th e iliac oblique sh ows th e posterior

A B

Figure 3.6 Radiographic lines of the acetabulum

on the obturator oblique x-ray. A: Iliopectineal line. B: Posterior rim. Note also the view of the obturator foramen as well as the ischial ramus. (Reprinted with permission from Bucholz RW, Heckman JD, CourtBrown C, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

43


A B

Figure 3.7 Radiographic lines of the acetabulum

on the iliac oblique x-ray. A: Posterior border of the innominate bone. B: Anterior rim. (Reprinted with permission from Bucholz RW, Heckman JD, CourtBrown C, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

colum n and the an terior rim of the acetabulum and can be identified by the en face view of th e iliac win g (Fig. 3.7). Major pelvic ring disruptions m ay be further assessed with inlet (beam an gled 20 ◦ caudally) an d outlet (beam angled 20 ◦ ceph alad) views. Th e inlet view depicts the degree of AP displacem ent across the pelvic ring. The outlet view depicts superoin ferior displacem en t an d n icely depicts pubic ram us fractures th at can be m issed on th e routin e AP (Fig. 3.8). Th e sacroiliac join ts are best assessed usin g con ed down AP views with a ceph alad beam an gulation of 30 ◦ , a view term ed th e Ferguson view. O blique projection s m ay be of som e ben efit, but th ey are difficult to optim ize. Routine evaluation of the h ip includes an AP view in in tern al rotation as above, as well as a frog leg lateral view with the h ip abducted and extern ally rotated. In th is way the requisite two orthogonal views are obtained without turn in g th e patien t. For traum a patien ts a groin lateral view of th e h ip can be obtain ed with an an gled beam aim ed at the groin, with the contralateral h ip flexed out of the beam . Th us, a lateral view of th e h ip is obtain ed with out m ovin g the injured hip.

is obtained with th e knee flexed 45 ◦ an d th e beam an gled alon g th e axis of th e tibial plateau. Th is view allows for evaluation of loose bodies an d osteoch on dritis dissecan s lesion s. Evaluation of th e patellofem oral join t is don e to look for arth rosis, m alalign m en t, or subluxation . Th e sunrise view of th e patella is acquired with th e patien t pron e an d th e kn ee in greater than 90 ◦ flexion, providing an axial view of the patella. It does not depict patellar subluxation or m alalignm en t, which m ust be assessed at lesser degrees of flexion. An oth er patellofem oral view is th e Merchant view in which the patient is supine and the knee is flexed to 45 ◦ with th e beam 30 ◦ from the horizon tal. The sulcus angle can be m easured on th is radiograph as th e an gle subten ded by the trochlea, wh ile th e con gruence angle is a m easure of patellar seatin g within the trochlea. Th e con gruence angle averages − 6 ◦ (arbitrarily defined as negative, i.e., 6 ◦ m edial to a zero referen ce lin e that bisects th e sulcus angle); a m ore positive congruen ce angle is indicative of patellar subluxation.

Foot and Ankle Knee Th e full series of radiograph s in th e evaluation of kn ee path ology in volves an AP view, a lateral view with 20 ◦ to 35 ◦ of flexion, and a view of the patellofem oral joint. In the evaluation of osteoarth ritis, th e AP views should be weigh tbearin g. In fact, AP weigh t-bearin g views of th e kn ee in 30 ◦ of flexion are m ore sen sitive for early join t space loss. In tern al an d extern al oblique 45 ◦ views can be h elpful in th e setting of proxim al tibial fracture to h elp evaluate fracture lin es (Fig. 3.9). A tunnel view or in tercon dylar n otch view

Routine radiograph ic assessm en t of the ankle begin s with AP, lateral, an d m ortise views. Mortise view is an AP view obtain ed with th e foot in 15 ◦ to 20 ◦ of in tern al rotation . Th is view takes in to accoun t th e fact th at th e fibula sits posterior to the tibia in th e coronal plane an d thus allows an assessm ent of th e lateral gutter of the an kle join t. Th e m ortise view will depict talar shift and ligam entous widening of th e syn desm osis. Th e m edial clear space an d th e tibiofibular clear space both serve as m easures of lateral talar sh ift an d can be m easured on the m ortise view. Th e

44


A

B

C Figure 3.8 A: Postoperative anteroposterior (AP) view of a right vertical shear pelvic injury. Fixation was achieved with a right iliosacral screw in conjunction with symphyseal plating. B: Inlet view. C: Outlet view. (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown C, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

m edial clear space is used as a m arker of lateral talar sh ift an d sh ould be less th an 4 m m as m easured on a m ortise view of th e an kle. Th e tibiofibular clear space is m easured from the m edial border of the fibular to the incisura fibularis on th e tibia on an AP view an d sh ould m easure less than 6 m m . Stan dard projection s of th e foot in clude AP, lateral, in tern al oblique, an d extern al oblique. Non –weigh t-bearin g views are adequate for assessin g an atomy but do n ot view the foot in a physiologic position an d are therefore suboptim al. Th e in tern al oblique complem en ts th e AP an d lateral an d especially evaluates th e lateral tarsom etatarsal articulation s. Tarsal coalition s, especially calcan eon avicular, can also be seen on oblique views.

Special views of th e h in dfoot can provide m ore in form ation. The Broden view provides a reliable im age of th e posterior facet of th e subtalar join t an d is used to evaluate intra-articular calcaneal fractures. It is obtained with th e an kle in n eutral dorsiflexion , th e leg in tern ally rotated 30 ◦ , an d th e x-ray beam cen tered over th e lateral m alleolus. Canale and Kelly described a talar n eck view for evaluation of talar n eck fractures. Th is view is obtain ed with the ankle in m axim al equin us with the foot pronated 15 ◦ an d centered 15 ◦ ceph alad (Fig. 3.10). An axial view of the calcaneus, the Harris-Beath view, allows an alysis of the m edial and posterior facets of the subtalar joint, as well as an assessm ent of the alignm ent of the heel. Fin ally, the Cobey view depicts h eel position an d axis relative


A

B

C

D

45

Figure 3.9 Standard radiographic trauma series. Internal oblique view (A), a lateral view (B), an

anterior-posterior (C), and an external rotation oblique (D) reveal a minimally displaced split fracture of the lateral plateau. (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown C, et al. Rockwood and Green’s Fractures in Adults, 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

to th e m ain tibial axis. It is perform ed PA with th e patien t stan ding on a platform with the beam angled 20 ◦ caudally.

CONVENTIONAL ARTHROGRAPHY In tra-articular n eedle placem en t un der fluoroscopic guidan ce can be perform ed for purposes of contrast injection,

fluid aspiration, or instillation of steroid or analgesic m edication . Con ven tion al arth rography h as been largely replaced by MRI, but it is still a useful tool for diagn osin g full-thickness rotator cuff tears of the shoulder and for evaluatin g th e in terosseous ligam en ts an d trian gular fibrocartilage com plex of th e wrist in patien ts un able to un dergo MRI scan . Th e basic prin ciple is th at con trast is in jected in to on e compartm en t an d sh ould n ot extravasate outside

46


75˚

15˚

Figure 3.10 Canale and Kelly view of the foot. The correct posi-

tion of the foot for x-ray evaluation of the foot is shown. (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown C, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

of th at compartm en t un less th ere is a disruption of th e tissue th at defin es th e com partm en t. For example, in th e sh oulder dye injected into the glen oh um eral joint sh ould not enter the subacrom ial space un less there is a tear of the rotator cuff allowing com m unication between the two areas. Con trast arth rography is n ot gen erally used for diagnosing loosen ing of arth roplasty com pon ents. However, fluoroscopic needle placem ent and aspiration are still im portan t as part of th e workup for deep in fection in pain ful join t replacem en ts. Arth rography an d ten ography can be used in th e foot an d an kle to h elp localize path ology an d guide in jection of steroid an d local an esth etic. Usin g con trast h elps to con firm proper position in g of th e n eedle an d can iden tify any anom alous connection between joints or between join ts an d ten don sh eath s th at m ay exist. C-arm fluoroscopy is an importan t tool for guidin g n eedle in jection of th e disk an d facet join ts in an effort to determ in e specific pain sources in both th e preoperative spin e patient an d patients with failed back surgery. Epidural injections and nerve blocks usin g lon g-acting steroids can also be perform ed under fluoroscopy as therapeutic procedures.

COMPUTED TOMOGRAPHY CT is a tech n ique th at gen erates cross-section al im ages that are reconstructed from m ultiple digital radiographic projection s or views. Th ese views are com bin ed th rough the m ethod of “back-projection’’ to generate the crosssectional im age. Recent advances in CT in clude the developm en t of h elical or spiral scan n ers, wh ich allows con tin uous un idirection al tube m otion . Ultim ately, th is al-

lows for m ore rapid acquisition of im ages, coverin g large body areas in a relatively sh ort period of tim e. Th is rapid acquisition has facilitated CT evaluation of the traum a patien t. Th e h elical CT also gen erates a th ree-dim en sion al projection al data set, allowin g retrospective recon struction of cross-section al im ages at arbitrary location s th rough out th e data set. Th ese recon struction s do n ot com e at th e cost of a h igher radiation dose to th e patien t. Newer m ulti-detector array CT will not only allow retrospective reconstruction of im ages at variable scan collim ation but also dram atically increase scan acquisition speed. Thinn er scan sections can be ach ieved at reduced radiation dose. CT is extrem ely h elpful in clarifyin g th e pattern an d severity of traum atic bony injuries and hence m ay be very h elpful in preoperative plan n in g. Compared with plain radiography, CT m ore accurately depicts th e relation sh ip an d degree of com m in ution of fracture fragm en ts. It is particularly helpful in the evaluation of articular fractures, pelvic an d acetabular fractures, an d calcan eal fractures. In articular fractures, join t surface depression and step-off, as well as iden tification of th e differen t pieces in to wh ich th e join t surface is fractured, allow for better un derstan din g of th e fracture pattern an d th erefore a m ore accurate approach to recon struction (Fig. 3.11). In deed, th e m ost com m only used classification of calcaneal fractures (Sanders’ classification ) is based on th e coron al cut of th e CT scan (Fig. 3.12). Although CT is chiefly used for problem solving and preoperative plan n in g in cases of skeletal traum a, it can also be used as an important and n ecessary adjun ct for diagnosis in skeletal areas that are difficult to evaluate with routin e radiography, such as th e spin e an d calcan eus. In stability or subluxation of th e distal radiouln ar join t (DRUJ) or stern oclavicular join t is difficult to diagn ose by radiography but can be accurately assessed with a fast, lim ited CT protocol. CT is n ow widely used in m ost traum a settin gs for clearing the cervical spine and, in m any cases, has supplan ted plain radiography in th is purpose. Many of th ese patien ts get a CT as a routin e part of th eir gen eral surgical traum a evaluation , so it is both cost-effective an d efficien t to add a cervical CT wh ile th e patien t is already in th e scann er. CT can be don e after in tra-articular adm in istration of dilute iodin ated con trast m edium or air to produce a CT arth rogram . Th e utility of CT arthrography is seen in a few settings. It can be useful in the shoulder in definin g instability lesion s of th e capsulolabral ligam en tous com plex. CT arth rography is ideally suited to the evaluation of calcified loose bodies within a joint. It also allows evaluation of the join t surface for ch on dral defects an d tears, th ough less accurately th an MR arth rography. CT arth rography can also provide in form ation about th e stability of ch ron ic osteochon dral lesions. In th e on cologic settin g, CT is often h elpful in ch aracterizin g bony lesion s an d evaluatin g th e exten t of cortical


47

Figure 3.11 True intra-articular tongue fracture (Type IIB). Plain radiographs are unable to indi-

cate whether the fracture involves the posterior facet. Semi-coronal and transverse CT scans verify intra-articular displacement. Note black arrows indicating intra-articular fracture, and white arrows indicating the intact lateral wall component typical of tongue fractures. (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown C, et al. Rockwood and Green’s Fractures in Adults, 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

bon e destruction . By depictin g lesion m in eralization an d pattern s of bon e destruction , CT m ay n arrow th e differen tial diagn osis. CT is less effective th an MRI at sh owin g the extent of m arrow involvem ent and the soft-tissue com pon en t of th e tum or. CT can sh ow soft-tissue exten sion , as well as possible involvem ent of neurovascular structures, although these componen ts are better im aged by oth er m ean s. In th e case of extraskeletal disease, th e use of in traven ous con trast is usually h elpful. Con trast can en hance the CT delineation of soft-tissue extension. Moreover, wh en perform ed as an an giogram , it can h elp to delineate the proxim ity of vascular structures. CT is also well

suited to th e fast and accurate guidance of needle biopsy procedures.

MAGNETIC RESONANCE IMAGING MRI has em erged as th e m ost versatile and powerful m eans of diagn ostic im agin g. It was developed as an offsh oot of tech n ology in itially developed for n uclear m agn etic reson an ce (NMR). It is based on th e detection of radiofrequen cy sign als em an atin g from hydrogen n uclei as th ey reson ate with in a stron g, static m agn etic field. Th ese sign als,

48


A

Central Med. Su st .

Lateral

A B C

B

Typ e IIA

A B

C

Typ e IIB

A

Typ e IIC

C

Type III AB

BC

Typ e III AC

Typ e III BC

A B C

Typ e IV

Figure 3.12 Sanders’ computed tomography (CT) scan classification of calcaneal fractures. (From

Sanders R. Current concepts review—displaced intra-articular fractures of the calcaneus. J Bone Joint Surg Am. 2000;82:233.) (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown C, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

sim ilar in frequency to FM radio signals, are generated by hydrogen n uclei after th eir selective an d carefully tim ed radio frequen cy excitation . Radiofrequen cy sign al stren gth is determ in ed ch iefly by th e n um ber of reson atin g proton s per tissue voxel, or proton den sity, an d by th e two relaxation

con stan ts, T1 an d T2. Th e so-called T1-weigh ted im ages favor proton species with sh ort T1 relaxation con stants, such as the aliphatic hydrogen n uclei in fat. T2-weighted im ages favor proton species with a lon g T2 relaxation con stan t, such as th e hydrogen nuclei in free water. Because of the


large m agnetic fields required for MRI scanning, patients with pacem akers or oth er m etallic devices or foreign bodies are unable to un dergo scans. MRI in n ovation con tin ues at a rapid pace, an d n ewer MRI techniques are both faster and higher in resolution. For orth opaedic im agin g, th e resolution requirem en ts are currently m ost important, but MRI can now gen erate inform ation about tissue physiology, such as th e diffusability of water m olecules, th e relative perfusion of organs, and the circulating blood volum e within tissues. Spectroscopic inform ation from MRI can also m easure and m ap bioch em ical m arkers of tissue structure and fun ction. The utility of th ese fun ction al MR tools for orth opaedic application s rem ain s to be explored. Reson atin g proton sign als are larger an d, correspon dingly, im age fidelity and resolution are improved at higher m agn etic fields. One point five- and th ree-tesla scan ners are con sidered “high field’’ units and are typically of a closedbore, tun n el-like design . Th ese h igh -field design s are m ore likely to result in claustrophobia for the patient an d their 55- to 60-cm bore diam eter is com m on ly un able to accom m odate very broad or obese patients. Open MRI design s usually employ a san dwich arran gem en t of perm an en t m agn ets and are usually of 0.3 tesla or lower field strength. Th ese un its are less claustroph obia in ducin g an d can accom m odate larger patients. The “open’’ feature confers the additional advantage that patients can be positioned such that the im agin g area of in terest is at “isocen ter,’’ or th e m ost h om ogen ous portion of th e m agn etic field. Th e lower field stren gth of open m agn et design s can be compensated for by lon ger scan tim es, but th ese units are still lim ited in their ability to im age sm all parts at h igh resolution . In traven ous, param agn etic con trast agen ts are ch elates of gadolin ium an d are routin ely adm in istered for MRI of th e cen tral n ervous system . Th e in dication s for in traven ous MRI contrast m aterial for m usculoskeletal im aging are m ore lim ited. An intravascular agent does provide inform ation about blood flow and capillary perm eability or leakage with in specific tissues of in terest. Th is m aterial is occasion ally h elpful in ch aracterizin g m ass lesion s with MRI. Con trast en h an cem en t m ay also be ben eficial in outlin in g reactive or in flam m atory tissues surroun din g abscesses. Fin ally, contrast m aterial en hancem ent m ay be of value in surveillance for recurrence of tum or after surgery or radioth erapy. Direct in tra-articular in jection of eith er salin e or a dilute solution of saline and a param agnetic MRI contrast agen t is known as MRI arthrography. This tech nique optim izes delineation of synovial joints an d th eir supportin g structures. MRI arthrography is m ost com m only used in the evaluation of instability lesion s of the shoulder. It m ay also be of value in the evaluation of the acetabular labrum of the hip. Th e h igh -con trast resolution of MRI offers a con siderable advantage over CT for the evaluation of soft tissues. MRI is also extrem ely useful for evaluation of the m arrow

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space, due to th e fat con ten t of the m arrow that generates a h igh MRI signal, at least on T1-weigh ted im ages. Pulse sequen ces th at suppress fat sign al are often useful in evaluation of th e m arrow, given th at path ologic ch an ges will sh ow up as an area of h igh sign al again st th e dark, fat-suppressed, m arrow sign al. Fat-suppressed im agin g, particularly th e STIR (sh ort tau in version recovery) tech n ique, is especially sen sitive to edem a or in flam m ation whether in bone or soft tissue, an d is also quite effective at delin eatin g disease exten t in th e case of n eoplasia. MRI evaluation of supportin g connective tissue structures requires h igh spatial resolution an d an appropriately tailored exam in ation th at targets th e specific structures of in terest. MRI is the best n oninvasive test for the evaluation of the join t surface (Fig. 3.13). Traum atic ch on dral tears as well as advan ced ch on dral loss are easily im aged, typically with som e form of T2-weigh ted im aging. Low-grade ch on drom alacia is also diagn osed accurately with h igh -resolution tech n iques. Th e in itial ch an ges of ch on drom alacia are difficult to visualize on MRI. Wh en MRI is perform ed with in traven ous con trast m aterial en h an cem en t, it is m uch m ore sen sitive th an radiography for the detection of early bone erosion in th e case of in flam m atory arth ritis. Th is in creased sen sitivity m ay have im plications for evaluating n ew therapies for rh eum atoid arth ritis. Unlike hyalin e cartilage, the fibrocartilaginous m eniscus of the knee is low in signal intensity on m ost MRI sequen ces. Meniscal derangem ent appears as zones of increased sign al again st the norm al, low signal fibrocartilage of th e m en iscus. Assessm en t of th e kn ee for possible m en iscal derangem ent is one of the m ost com m on reasons a m usculoskeletal MRI is ordered. With m odern MRI, th e sen sitivity an d specificity of MRI for m eniscal tear are each over 90% (Fig. 3.14). MRI also provides in form ation about the orientation of the tear and the presence of displacem en t (Fig. 3.15). It m ust be rem em bered, h owever, th at MRI fin din gs m ust be correlated with clin ical symptom s, as th e in ciden ce of m en iscal tears h as been proven to be h igh in older patients in th e absen ce of symptom s. As in oth er areas of th e body, MRI sh ould be used as a con firm atory test to con firm a clin ical suspicion based on h istory an d physical exam in ation fin din gs. Fibrocartilaginous supporting structures in other join ts, that is, th e labrum of the shoulder and the hip, can also be evaluated by MRI. Th ese structures, h owever, are less easily evaluated th an th e m en iscus of th e kn ee. MR arth rography is superior to con ven tion al MR for th e evaluation of th e labrum of th e sh oulder, especially in th e setting of in stability. MR arthrography can help identify th e spectrum of in stability lesion s in cludin g Ban kart lesion s, h um eral avulsion of th e glen oh um eral labrum (HAGL), an terior labroperiosteal sleeve avulsion (ALPSA), an d glen oid labrum articular disruption (GLAD) lesion s (Fig. 3.16). MRI is effective at diagnosing acute ligam entous in juries. It h as a specificity an d sen sitivity of over 95% in th e

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A

B

Figure 3.13 Three-dimensional gradient-echo images (A–

C) of the knee from posterior to anterior demonstrating superior cartilage detail. (Reprinted with permission from Berquist TH. MRI of the Musculoskeletal System. 5th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

evaluation of an terior cruciate ligam en t (ACL) ruptures. Th e ch aracteristic bon e bruise pattern seen in MR im ages is a bon e bruise on th e posterior lateral tibia with a correspon din g bruise on th e fem oral con dyle. It is sim ilarly useful in evaluatin g acute ligam en tous in juries in oth er locations. However, it is less useful in the evaluation of the ch ron ically in sufficien t ligam en t. The m ultiplan ar im aging capability and high soft-tissue contrast of MRI m akes it ideally suited to th e evaluation of the spine. Spinal can al and foram inal stenosis, as well as alteration s in spin al align m en t, can be accurately assessed. Th e in tervertebral disk is clearly depicted, with th e n ucleus pulposus bein g h igh er in sign al in ten sity th an th e an n ulus fibrosis an d th e posterior lon gitudin al ligam en t. Disk protrusion s, extrusion s, an d sequestration s can be differen tiated (Fig. 3.17). Th e role for CT myelography con tin ues to dim in ish as MRI tech n iques improve. In cases of m ajor traum a an d suspected in stability, MRI is a safer an d m ore effective test for ligam en tous spin al in jury an d po-

C

ten tial in stability th an tradition al flexion an d exten sion radiograph s. T2 STIR im ages are especially effective for evaluatin g ligam en tous spin al in jury. MRI is quite sen sitive for ten don disruption s if studies are perform ed with sufficient spatial resolution. This application is useful in th e stagin g of im pin gem en t in th e sh oulder with ten don osis with in th e rotator cuff ten don s. It can sh ow the spectrum from tendonosis to partial-thickness and ultim ately full-thickness tears, although it can be difficult to differen tiate ten don osis from partial-th ickn ess tearing. Short echo tim es are especially useful in th e im aging of ten don osis wh erever it m ay occur in th e body, alth ough MRI is m ore useful in m aking these distin ctions in the larger rotator cuff an d th e Ach illes tendon (Fig. 3.18). MRI is sen sitive in detectin g m uscle sprain s an d tears. In suspected cases of h am string injury, for example, MR evaluation m ay be of som e prognostic value, particularly in elite athletes in wh om the size of injuries, the extent of intram uscular fluid collection s, an d th e presen ce of h em orrh age can


Figure 3.14 Sagittal gradient-echo image demonstrating a hor-

izontal cleavage tear in the posterior horn. (Reprinted with permission from Berquist TH. MRI of the Musculoskeletal System. 5th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

be delin eated. MRI is also sen sitive to oth er physiologic an d path ologic ch an ges in m uscle. Tran sien t ch an ges in m uscle signal are seen on MRI im m ediately after exercise, likely related to shifts in m uscle water compartm entalization . For reason s th at are n ot well un derstood, MRI, an d particularly STIR sequen ces, are very sen sitive to m uscle alteration s th at

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occur very early in den ervation states an d n europraxia an d thus m ay serve as a useful adjunct to electrodiagn ostic studies. Th ese MRI sign al ch an ges occur very early an d precede electromyograph ic ch an ges. Fin ally, MRI effectively m aps the often heterogeneous ch anges seen in inflam m atory myopath ies. Th is capability m ay con tribute to m ore effective, im age-guided m uscle biopsy for diagn osis of th ese often complex and confusing disease entities. Alth ough cortical bon e itself does n ot produce an MRI signal, th e cellular an d fatty elem ents in bon e m arrow do, an d th us, MRI h as becom e a powerful tool in diagn osin g in filtrative, in flam m atory, an d traum atic con dition s of bon e. Fairly specific MRI chan ges are seen in avascular necrosis of bon e, in wh ich zon es of n ecrotic m arrow becom e dem arcated by reactive tissue and edem a that exhibit abnorm al MRI sign als relative to n orm al m arrow (Fig. 3.19). Th ese ch an ges are eviden t with in weeks of th e isch em ic even t, an d the MRI findin gs are m ore specific and seen with greater resolution th an th ey are with bon e scan . Sim ilarly, the m arrow reactions to both stress and traum a create alteration s in th e bon e m arrow sign al th at m ake MRI a very sen sitive m ean s to diagn ose fractures, both of th e fatigue an d traum atic variety. In m any cases, MRI will visualize th e fracture or fatigue zon e as a low signal lin e, wh ich con fers greater specificity in diagnosis compared with bone scan. MR, like bone scan, is very sensitive for bony in jury sh ort of frank fracture (Fig. 3.20). Th ese lesions can be referred to as ”bon e bruises or stress reaction s,” depen din g on wh ere th ey are in th e body. MRI allows for m ultiplan ar im agin g an d h igh resolution , wh ich

PCL

A

B Figure 3.15 Coronal fat-suppressed T2-weighted image (A) demonstrating a medial tear (curved

arrow) with a large displaced fragment (black arrow) that gives the appearance of two posterior cruciate ligaments (PCLs). There is also a complex tear of the lateral meniscus (white arrow) and loss of articular cartilage. Sagittal proton density-weighted image (B) demonstrating a medial meniscal tear with a large displaced fragment (small arrow), resulting in a double-PCL sign. (Reprinted with permission from Berquist TH. MRI of the Musculoskeletal System. 5th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

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B A

Figure 3.16 Labral tears. A: Axial MR arthrogram im-

age demonstrates an anterior tear (arrow). Axial T1- (B) and T2-weighted (C) arthrogram images demonstrate anterior labral tears (arrow). (Reprinted with permission from Berquist TH. MRI of the Musculoskeletal System. 5th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

on ce again provides a superior evaluation compared with bon e scin tigraphy. The sensitivity of MRI to m arrow edem a an d soft-tissue in flam m ation m akes MRI an effective test for osteomyelitis. Th e use of in traven ous con trast m aterial is n ot essen tial but m ay aid in iden tifyin g areas of n ecrosis or abscess form ation . Th e h igh resolution will often m ake MRI a m ore useful preoperative study th an bon e scan (Fig. 3.21). Bon e scan does h ave the advan tage that it can survey larger areas, whereas MRI is best used in a fashion directed by h istory an d physical exam in ation . Th e utility of MRI an d bon e scan both is decreased if th ere h as been prior recen t traum a or surgery th at m igh t impart alterations in bone m arrow physiology, m im ickin g th ose of in fection . MRI is very sen sitive for detectin g m arrow replacem en t th at occurs in m etastatic an d prim ary tum ors of bon e. It is m ore sen sitive an d specific for m etastatic disease to bon e th an eith er CT or bon e scan . MRI accurately defin es th e exten t of disease in th e m arrow space an d delin eates extraosseous exten sion of tum or (Fig. 3.22). Although the sign al ch aracteristics of tum ors are not usually specific, MRI is quite effective in distin guish in g cystic m asses from solid m asses an d iden tifies th e presen ce of

C

secon dary aneurysm al bone cyst components and tum or n ecrosis. MRI is n ot usually used to diagn ose diffuse m arrow diseases such as leukem ia an d myelom a. Th ese in filtrative diseases can be difficult to detect by MRI. Sign al ch aracteristics on norm al MRI sequences m ay not reliably distinguish th ese m arrow in filtrates from n orm al h em atopoietic or red m arrow. The pattern or extent of m arrow cellularity (i.e., th e replacem en t of n orm al yellow m arrow) is m ore tellin g th an th e in filtrates th em selves. MRI is th e m odality of ch oice for th e im agin g evaluation of suspected soft-tissue tum ors. The utility of MRI is prim arily in lesion detection an d delin eation , wh ich aids m anagem ent an d surgical or biopsy planning. MRI has a h igher sensitivity for soft-tissue m asses th an does CT (Fig. 3.23). Alth ough MRI features are n ot usually specific for on e h istologic diagn osis, MR does often con tribute in form ation that m ay significantly narrow the differential diagn osis. O ccasion ally, specific diagn oses can be m ade with con fiden ce based on MRI, particularly in th e case of vascular origin or fat-containin g tum ors. The use of intraven ous con trast m aterial m ay aid in th e iden tification of tum or n ecrosis an d th e con firm ation of th e cystic n ature of certain


A

C

B

D

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Figure 3.17 Lumbar disc protrusion. L3 disc herniation with the base of the herniation wider than the distance away from the parent disc. The protrusion is evident principally as a distortion of the cerebrospinal fluid–containing thecal sac on the T2-weighted images (A and B) and as effacement of the epidural fat on the T1-weighted images (C and D). (Reprinted with permission from Berquist TH. MRI of the Musculoskeletal System. 5th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

lesions. It is not, h owever, essential to the MRI evaluation of m ass lesion s.

ULTRASONOGRAPHY Ultrasound has the distin ct advan tages of being sem iportable, easily tolerated, an d relatively in expen sive. With new transducer technology, ultrasoun d can surpass MRI an d CT in spatial resolution an d can be effectively used in the im aging of sm all an d superficial body parts. Th e m ain drawback to ultrasoun d is th at th e quality of th e im ages is extrem ely dependent on the skill of the technician per-

form in g th e ultrasound. Furtherm ore, m ost orth opaedists are n ot able to in terpret ultrasoun d im ages on th eir own , so th ey m ust rely on the radiologists report. Com m on examples of the clinical application of highresolution ultrasoun d in clude th e diagn osis of Morton ’s n eurom a an d gan glion cysts. Ultrasoun d is well suited to the evaluation of tendonopathy and reliably detects ruptures of ten don s. Com m on clin ical application s in clude evaluation of th e Ach illes ten don an d th e rotator cuff. Ultrasoun d can be used to evaluate ligam en tous structures, alth ough a workin g kn owledge of an atomy is a prerequisite. In th is settin g it h as th e advan tage of allowin g for dynam ic evaluation as opposed to the static im ages

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Figure 3.18 Complete Achilles tendon tear. Sagittal T2-

weighted image of the ankle demonstrates high signal intensity with thickening and retraction of the proximal fragment (arrow) commonly seen with complete tears. (Reprinted with permission from Berquist TH. MRI of the Musculoskeletal System. 5th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

produced by tradition al im agin g tech n iques. For exam ple, ultrasoun d can be used to assess disruption of th e uln ar collateral ligam ent of the thum b m etacarpal-phalangeal join t, th e so-called Gam ekeeper’s th um b, by im agin g th e ligam en t, as a deform in g force is applied to th e th um b. As a real-tim e im agin g m odality, ultrasoun d is also well suited

for im agin g guided biopsies. It can also be used effectively to identify foreign bodies n ot seen on x-ray. Ultrasound has perhaps been underutilized in the evaluation of soft-tissue m ass lesion s. It is particularly effective in determ inin g the vascularity of lesions, particularly with th e adven t of real-tim e color Doppler im agin g tech n ology. Power Doppler display is an alogous to th e circulatin g blood volum e, an d it is h igh ly sen sitive to low-velocity flow. With th is en han cem en t ultrasoun d can accurately assess the vascularity of lesions and can identify hyperem ia around in flam m atory m asses. Ultrasound can be used in m ore than one setting in pediatric patients. A short ultrasound evaluation m ay be useful in excludin g the presence of a joint effusion and possibly obviatin g n eedle aspiration . Also, ultrasoun d is th e im aging m odality of choice in the evaluation of infants with suspected developm en tal dysplasia of the hip. Ultrasound allows both a static evaluation an d a dyn am ic evaluation to assess for potential dislocation, dislocatability, and subluxability of th e hip. Ultrasound can be perform ed with a Pavlik h arn ess in place, an d it can also be used to follow th e m aturation of th e h ip join t un til th e capital fem oral epiphysis can be seen radiograph ically wh en it begin s to ossify at 12 to 18 m on th s of age.

NUCLEAR SCINTIGRAPHY Th e specificity of n uclear m edicin e studies is determ in ed by the radiopharm aceutical agent th at is adm inistered. Selective uptake of radiopharm aceutical agents occurs in tissues in a temporally predictable fashion. The radiotracer portion of th e radioph arm aceutical is typically a gam m a-em ittin g

A

B

Figure 3.19 SE 500/10 images of the hips in a patient with early AVN on the right. Radiographs

were normal. A: Coronal image demonstrating a small linear subchondral defect (arrow). B: Sagittal image of the right hip more clearly defines the extent of involvement (arrows). (Reprinted with permission from Berquist TH. MRI of the Musculoskeletal System. 5th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)


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A

Figure 3.20 Patient with right hip pain and

normal radiograph (A). Coronal T1-weighted image (B) demonstrates decreased signal intensity due to edema and a fracture at the base of the femoral neck (arrow). (Reprinted with permission from Berquist TH. MRI of the Musculoskeletal System. 5th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

B

isotope, and the distribution of th e radiopharm aceutical is im aged by a gam m a (scintillation ) cam era. These cam eras h ave large faces an d can scan large areas of th e body quickly to produce plan ar im ages. Gam m a cam eras can also be design ed to rotate aroun d th e patien t to collect m ultiple views, which can then be recon structed into tom ograph ic or cross-section al im ages in various plan es. Th is application is referred to as SPECT (single photon em ission com puted tom ography) im agin g. Tech n etium -99 m ( 99m Tc) is the radioisotope used m ost com m only for clinical scintigraphy because of its in expen sive production from portable gen erators, con ven ien t h alf-life of 6 h ours, an d a principle ph oton en ergy of 140 keV, wh ich is well suited to detection by gam m a cam eras. Skeletal scin tigraphy, or bon e scan , is th e n uclear m edicine exam ination m ost com m only perform ed for the evaluation of orth opaedic problem s. Im agin g com m en ces approxim ately 2 to 4 hours after the intravenous adm inistration of th e radiopharm aceutical, wh ich is usually 99m Tcm ethylene diphosphonate (MDP). The MDP bone scan is highly sensitive for a diversity of bony abn orm alities, im ages the entire skeletal system , and is well tolerated by pa-

tien ts. Im age acquisition requires 30 to 40 m in utes. Th e uptake of 99m Tc-MDP is determ in ed by both th e osteoblastic activity of bon e an d th e blood flow to th e bon e. MDP uptake is dim in ish ed in osteoporosis an d in patien ts wh o are on bisph osph on ate th erapy. Th e m ost com m on application of skeletal scin tigraphy is in detecting m etastatic disease, for which the sensitivity approaches 95%. Metastatic disease causes altered bon e m etabolism that subsequen tly effects a focal in crease in uptake of MDP. Metastatic disease is detected m uch earlier on bon e scan s than on radiography (Fig. 3.24). Bon e den sity h as to chan ge by 30% to 50% before a plain radiograph will depict infiltrative disease; th erefore, bon e scan n in g is the m ost appropriate m eans to establish m etastatic disease in m ost cases. However, certain aggressive and purely osteolytic tum ors, such as m ultiple myelom a, m ay n ot produce in creased uptake on bon e scan , or th ey m ay presen t as ph oton -deficien t or “cold’’areas th at can be overlooked. Con sequen tly, m ultiple myelom a is staged with a radiograph ic skeletal survey. O ccasion ally, after effective ch em oth erapy, m etastatic bon e lesion s m ay exh ibit in creased osteoblastic activity th at

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Figure 3.21 Osteomyelitis in the left femur. Coronal STIR se-

quence shows subtle thickening of the cortex with increased signal intensity in the marrow and adjacent soft tissues. (Reprinted with permission from Berquist TH. MRI of the Musculoskeletal System. 5th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

m an ifests as in creased activity on follow-up bon e scan s an d is kn own as th e “flare’’ph en om en on . Th erefore, in creased uptake in th is settin g sh ould n ot be in terpreted as a sign that m etastatic disease has progressed. With advanced and diffuse m etastatic disease (typically secon dary to prostate or breast carcin om a), th e bon e scan m ay sh ow such diffusely increased bone activity that it assum es a pseudonorm al appearan ce, kn own as a ”superscan .” Th is scan m ay be recogn ized by n otin g th e dim in ish ed or absen t ren al tracer activity th at also ch aracterizes m ost of th ese cases. Bone scintigraphy is of lim ited value in im aging prim ary bon e n eoplasm s. Th e area of uptake m ay n ot reflect th e true tum or m argin s, an d soft-tissue in volvem en t will n ot be appreciated. Bon e scan s are n ot reliable in distin guish in g m align an t from ben ign lesion s, alth ough th e pattern of uptake m ay reflect th e aggressiven ess of th e lesion . In evaluatin g wh at is presum ed to be a solitary bon e lesion , a bon e scan is m ain ly useful in excludin g m ultifocal disease or un suspected m etastatic disease. Clin ical h istory an d exam in ation are importan t in in terpretin g bon e scan s, as tracer uptake is h igh ly n on specific. Sites of bony traum a an d degen erative join t disease will routin ely appear as in ciden tal, focal areas of in creased radiotracer uptake on bon e scan . Bon e scan s are th erefore good studies in detectin g occult an d stress fractures. About

80% of occult fractures are seen at 24 h ours after fracture and 95% by 3 days. Th e greatest tracer uptake is seen approxim ately 7 days after fracture. Bon e scan s will revert back to norm al at about 1 year after fracture. Stress fractures and stress reaction s appear as focal increased areas of tracer uptake, wh ile th e related en tity of sh in splin ts appears as a m ore diffuse area of increased tracer localization. Avascular necrosis, regardless of cause, can be readily identified on bone scan, although the appearance depends on th e tim e course of th e disease process. Because of th e decreased blood flow to th e site, recen tly in farcted bon e will appear photopenic. Depiction of the infarcted, photopenic areas requires spatial resolution, possibly requiring SPECT im aging. Later in the disease process, healin g an d new bone form ation will appear as increased activity about the area of infarction. This presen tation can be difficult to distinguish from arthrosis. Osteomyelitis, especially in its acute form , can be diagnosed by bon e scanning m uch m ore readily than with plain radiography. Radiotracer uptake will gen erally be in creased at sites of osteomyelitis with in th e first 24 h ours of infection, while radiographic change occurs later in the disease process. Dyn am ic m ultiph ase im agin g h eigh ten s th e specificity of bon e scan by better differentiatin g osteomyelitis from cellulitis or septic arth ritis. The first phase (flow ph ase) con sists of dyn am ic acquisition of im ages over th e area of in terest every 2 to 5 secon ds for the first 1 to 3 m inutes after injection an d reflects region al blood flow. In th e secon d ph ase, static im ages are obtain ed durin g th e first 10 to 20 m inutes after injection after adequate recirculation of tracer; th is phase is kn own as the ”blood pool or tissue phase” and reflects circulating blood volum e. For th e th ird, or delayed, ph ase, im ages are obtain ed 2 to 4 h ours after injection, at which point substantial clearance of soft tissue and blood pool activity has occurred. Increased activity on all th ree ph ases of bone-scan im aging is seen in osteom yelitis, wh ereas cellulitis is abn orm al on on ly th e first two phases. However, a positive three-ph ase bone scan is not entirely specific for osteomyelitis and can be seen in inflam m atory arth ritis, gout, acute fracture, reflex sympath etic dystrophy, an d n europath ic join t disease. Th e sen sitivity of the three-ph ase bone scan m ay also be decreased in cases of severe peripheral vascular disease and in the diabetic foot. Gallium -67 citrate h ad tradition ally been used in con jun ction with tech n etium to in crease th e specificity of diagnosis for osteomyelitis. More recently, scanning with labeled leukocytes h as largely supplan ted gallium scan n in g in th e scintigraph ic evaluation of osteomyelitis and softtissue abscesses. Gallium still has use in a few settings, however. Gallium can be useful to evaluate poten tial disk space and vertebral in fections. It can also be used in the evaluation of pediatric patients in that gallium is not as fully taken up by th e growth plate as is tech n etium . Gallium is also useful for staging and assessing progression in patients with lymph om a.


A

B

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C

Figure 3.22 Pathologic compression fracture of the T4 vertebral body in a 73-year-old woman

being evaluated for metastatic disease after identification of a lung carcinoma. A: Lateral thoracic spine radiograph shows marked compression fracture of the T4 vertebral body. No other lesions are seen. B: Large field of view T1-weighted (500/15) SE MR image of the spine shows the fracture at T4 (asterisk) and as partial replacement of the marrow in the T3 vertebral body and T6 vertebral body. C: Corresponding small field of view lateral T1-weighted (500/15) image shows areas of marrow replacement to better advantage. Transpedicular biopsy of the T4 lesion revealed multiple myeloma. (Reprinted with permission from Berquist TH. MRI of the Musculoskeletal System. 5th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

A

B

Figure 3.23 Synovial sarcoma in the ankle of a 37-year-old woman. Coronal T1-weighted (600/20)

(A) and axial T2-weighted (2,000/80) (B) SE MR images show a large well-defined mass, with a complex signal intensity compatible with previous hemorrhage. Note subtle area of bone invasion in A (open arrow). (Reprinted with permission from Berquist TH. MRI of the Musculoskeletal System. 5th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

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does as well, th en th e wh ite cell accum ulation is deem ed physiologic. Wh ite cell localization with a n egative m arrow scan is indicative of infection . The accuracy of white blood cell scannin g for osteomyelitis is lower in the spine, and it m ay also be dim inish ed after antibiotic therapy and in cases of chronic osteomyelitis. Th e availability of wh ole-body positron em ission tom ography (PET) im agin g is in creasin g. In particular, fluorine-18-fluorodeoxyglucose PET (FDG-PET) im aging h as gain ed acceptance for its ability to effectively stage tum ors an d evaluate for recurren t n eoplasia. Th is im agin g tech nique, which identifies sites of increased glucose utilization , is also an altern ative m eth od to diagn ose osteomyelitis in complicated clin ical settin gs.

BONE DENSITOMETRY

Figure 3.24 Radionuclide bone scan demonstrates abnormal ra-

diotracer uptake within the midshaft of the left humerus, right iliac crest, and right acetabulum, which is suspicious for bone metastasis. Increased uptake within the shoulder joints is related to osteoarthritis. (Reprinted with permission from Chew F, Roberts C, Musculoskeletal Imaging: A Teaching File, 2nd ed. Philadelphia PA: Lippincott Williams & Wilkins, 2006.)

Leukocyte scintigraphy (i.e., white blood cell scan) has largely replaced gallium scann in g for th e assessm en t of complicated osteomyelitis. A wh ite blood cell scan is perform ed by separatin g wh ite blood cells from approxim ately 50 m L of whole blood. These cells are then labeled with eith er in dium -111 oxin e or 99m Tc h exam ethylpropylen am in e oxim e (HMPAO ). Th e labeled cells are th en rein troduced in to th e patien t. Scan nin g is usually perform ed at about 6 an d 12 h ours after th e in jection . Technetium is preferable to gallium for this purpose because th e sh orter h alf-life of tech n etium perm its a larger dose to be used. Th is m ore favorable dosin g allows for a higher count rate an d therefore a h igh er resolution im age. Labeled white cell studies have proven to be effective in diagnosing infection about total joint arth roplasties and internal fixation hardware. Regular bone scanning is som ewh at lim ited for th is in dication , alth ough it can give som e inform ation about prosthetic loosening. Localization of wh ite blood cells aroun d orth opaedic implan ts is n ot en tirely diagnostic of infection, and, indeed, localization can occur in th e absen ce of in fection . However, if th e wh ite blood cell scan is correlated with a tech n etium colloid m arrow scan , th e diagn ostic capability is en h an ced. If th e wh ite blood cell scan sh ows stron g uptake an d th e m arrow scan

Osteoporosis is increasingly being recognized as a m ajor public h ealth problem , with h uge atten dan t h ealth care costs and m orbidity rates. Bone densitom etry studies are in creasingly used to assess fracture risk an d to guide treatm ent decision s. Guidelin es for th e use of th is im agin g m odality con tinue to evolve. Th e tech n ique th at is m ost com m on ly used for osteoporosis screen in g is dual en ergy x-ray absorptiom etry (DEXA). Routine DEXAscreening is perform ed on th e lum bar spin e an d th e h ip. Th e dual-en ergy feature of th is exam in ation perm its separate calculation of x-ray attenuation from bone and from soft tissue. In th is way th e bone m ineral con ten t can be derived from a two-dim en sion al projection technique. Modern DEXA scan ners utilize a fan-beam x-ray source an d are th us quite fast (< 5 m in utes for im age acquisition). Th e advan tages of DEXA over tradition al m eth ods of osteoporosis im agin g are th e extrem ely low radiation dose (< 5 m rad), h igh precision , an d relatively low cost. Measured bone m ineral den sity from DEXA exam in ations is m ost com m only expressed as a stan dard deviation from the m ean bone density of h ealthy young control subjects ( T score), or, less im portant, as a standard deviation from the m ean for age- and sex-m atched control subjects ( Z score). A T score between − 1 and − 2.5 in dicates osteopen ia, wh ereas a T score of less than − 2.5 is diagn ostic of osteoporosis. Various region s of in terest are reported for the hip, but the bone m ineral content of the fem oral neck is probably th e m ost precise and, therefore, the m ost useful m easurem en t.

RADIATION EXPOSURE CONSIDERATIONS One furth er subject that m ust be broached in this review is that of radiation exposure to th e orthopaedic surgeon. Radiograph ic visualization is a n ecessary part of m any orthopaedic procedures, an d m any orthopaedic surgeons are


poorly educated about th e perils of radiation exposure an d steps that can be taken to avoid poten tially h arm ful radiation exposure. Radiation safety and protection largely falls un der th e jurisdiction of th e U.S. Food an d Drug Adm in istration (USFDA), which typically follows the advice of advisory bodies such as the Nation al Council on Radiation Protection an d Measurem en ts (NCRP) an d th e In tern ation al Com m ission on Radiological Protection (ICRP). These advisory bodies periodically review th e scientific literature an d m ake recom m endation s regardin g radiation safety an d protection . Th ere are various un its used to m easure radiation exposure, but the SI un it is Gray. Gray is a unit of m easurem en t defin ed as 1 Joule (J) of en ergy deposited in 1 kg of m aterial. However, the unit m ost com m on ly used in th e literature, an d that which is used to define exposure lim its, is the rem . One m illiGray (m Gy) is equal to 100 m illirem s (m rem ). To put exposures in perspective, th e m in im um dose that causes skin erythem a is approxim ately 2 to 3 Gray. Death occurs in 10 to 24 h ours after exposures of 6 to 10 Gray. Of greater practical con cern are th e risks associated with low-level radiation exposures, an d th ese are estim ated from m ath em atical and statistical m odels. The in crem ental lifetim e risk of can cer (usually leukem ia or lymph om a) is estim ated to be approxim ately 0.1% per 0.01 Gray. Expressed differen tly, if 100,000 people each received a dose of 0.01 Gray, approxim ately two n ew cases of can cer would be an ticipated per year, based on a life expectan cy of about 75 years. In th e term s of an orth opaedic surgeon , th e prim ary way to decrease radiation effects is to m inim ize exposure, both by usin g radiation on ly wh en n ecessary an d by wearing appropriate shielding. Hands are at the greatest risk for exposure. Using a regular C-arm , exposure rates for an orthopaedic surgeon are estim ated to be as high as 20 m rem per m in ute to th e torso an d 30 m rem per m in ute to th e h an ds. If a given in tram edullary rod procedure requires 5 m in utes of fluoroscopy, th en th e exposure dose to the surgeon is 100 m rem for the torso and 150 m rem for the hands. Protection of th e torso can reduce that exposure to 10 m rem , but th e h an d exposure rem ain s. Th e curren t

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NCRP guidelin e allows 5 rem of exposure to th e torso an d 50 rem exposure to the hand yearly. Using these num bers, an orth opaedic surgeon would th ereby be lim ited to on ly 333 cases with this degree of exposure in one year. Wh ile these guidelines are just th at (i.e., n ot law), one m ust realize the serious and potentially detrim ental nature of radiation exposure an d m ust n ot take it ligh tly. As stated above, th e best way to m in im ize risk is to avoid exposure and wear shielding. Other ways to accom plish th is goal in clude usin g a m in i C-arm , in vertin g th e C-arm , an d in creasin g on e’s distan ce from th e C-arm . Usin g a m in i-C-arm , average radiation dose to th e h an d in a given case is 20 m rem . Th e radiation dose with th e m in iC-arm is typically about 10% of th at of th e dose with th e regular C-arm . O n e m ust rem em ber, h owever, th at typically on e works m uch closer to th e beam wh en usin g a m in i-Carm an d also closer to th e scatter created. Trem ain s et al. n oted th at the radiation dose to th e patien t an d th e surgeon is sign ifican tly less if th e C-arm is in verted. With th e regular C-arm , studies h ave sh own th at on ly th ose with in 6 ft of th e beam n eed to wear protective sh ieldin g, as th e dose precipitously drops off th e furth er on e gets away from th e beam . Th is distan ce for th e m in i-C-arm is 3 ft. Despite th ese facts, it is probably best for th ose wh o are often in th e settin g of fluoroscopy to use protection every tim e.

RECOMMENDED READINGS Dom b BG, Tyler W, Ellis S, McCarthy E. Radiographic evaluation of path ological bone lesions: current spectrum of disease and approach to diagnosis. J Bone Joint Surg Am. 2004;86-A(suppl 2): 84 –90. Grissom L, Harcke HT, Thacker M. Im aging in th e surgical m anagem ent of developm en tal dislocation of th e hip. Clin Orthop Relat Res. 2008;466(4):791 –801. San ders TG, Miller MD. A system atic approach to m agn etic reson an ce im aging interpretation of sports m edicine in juries of the knee. Am J Sports Med. 2005;33(1):131 –148. San ders TG, Morrison WB, Miller MD. Im agin g tech n iques for th e evaluation of glen oh um eral in stability. Am J Sports Med. 2000; 28(3):414 –434. Sh in dle MK, Foo LF, Kelly BT, et al. Magn etic reson an ce im agin g of cartilage in the athlete: current techniques and spectrum of disease. J Bone Joint Surg Am. 2006;88(suppl 4):27 –46.

4

Electrodiagnostic Testing Michael K. Ku o

INTRODUCTION Electrodiagnostic medicine is “a specific area of m edical practice in which a physician integrates inform ation obtain ed from the clinical history, observations from physical exam ination, and scien tific data acquired from recording electrical potentials from th e nervous system and m uscle to diagn ose, or diagn ose an d treat diseases of th e cen tral, periph eral, an d auton om ic n ervous system s, n eurom uscular junctions, an d m uscle.’’ Electrodiagn ostic testing typically con sists of two components, nerve conduction studies (NCS) and electromyography (EMG). It is critical th at electrodiagn ostic testin g be used as an exten sion of a focused h istory an d physical exam in ation . Th e h istory an d exam in ation is used to form ulate an in itial differen tial diagn osis. Based on th is differen tial diagn osis, specific nerves an d m uscles are exam ined with NCS and EMG. Th e tech n iques used as well as th e specific n erves an d m uscles exam ined are initially determ ined by this differential diagnosis. The early NCS and EMG findings will determ in e wh at addition al testin g is required an d will further narrow the differential diagnosis. The electrodiagnostic impression is determ ined not only by the test results but also by the clinical inform ation. Relying solely on the electrodiagnostic data to form ulate an impression frequen tly leads to m isdiagnosis. For example, n orm al NCS and EMG for a patient with a clinical lum bar radiculitis does n ot rule out a lum bar n erve root source for th e patien t’s sym ptom s. Th e diagn ostic lim itation s of NCS an d EMG m ake clin ical correlation crucial. Electrodiagn ostic testing is used as a tool for diagnosing n eurom uscular disorders. Although in form ation can be obtain ed regardin g th e cen tral n ervous system , electro-

diagn ostic testin g is prim arily used to diagn ose periph eral n ervous system and m uscle disorders. An atom ically th is m ay in clude an terior h orn cells, sen sory an d m otor roots, brach ial an d lum bosacral plexuses, periph eral n erves, n eurom uscular jun ction s, an d m uscles. In addition to diagn osis, electrodiagnostic testin g can h elp with localization, determ in in g severity, an d progn osis. For example, a patien t with h an d n um bness can be diagn osed with a m edian n europathy with NCS an d EMG. Th e testin g can furth er localize the lesion to the wrist or forearm , determ in e which nerve fiber types are in volved (m otor/ sen sory), verify h ow m uch axon loss versus demyelin ation h as occurred, an d give a progn osis based on th is in form ation .

NERVE CONDUCTION STUDIES NCSin volve th e in duction of a propagatin g action poten tial alon g a peripheral nerve an d the subsequen t recording of th is electrical waveform . Th e in duction is perform ed with a brief electrical stim ulus from a stim ulator probe applied to th e surface of th e skin overlyin g th e periph eral n erve to be exam in ed. Th e recordin g is perform ed by placin g recording electrodes over a m ore distal portion of the peripheral n erve or over a m uscle th at is in n ervated by th e n erve. The waveform s produced have param eters that can provide in form ation regarding the location of the in jury and type of path ology in volved (axon loss vs. dem yelin ation ). Basic NCS in clude motor NCS an d sensory NCS. Late responses (F-waves an d H-reflexes) can provide addition al in form ation regarding proxim al portions of tested peripheral n erves. Repetitive nerve stimulation ( RNS) studies are useful for diagnosing neurom uscular junction disorders.

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Patient Preparation In preparin g for NCS, patien ts are in structed to avoid skin cream s and lotions as surface electrodes m ay not fasten securely to the skin . There are no absolute contrain dication s for NCS, alth ough th ese are n ot recom m en ded in patien ts with extern al cardiac pacem akers. In patien ts with implan ted cardiac pacem akers, NCS can be perform ed as lon g as stim ulation n ear th e th orax is avoided. In patien ts with central lines, stim ulation over th e central lin e site is not recom m ended as the electrical im pulse could travel to the heart via the cath eter.

Sensory NCS Sen sory NCS are perform ed by placem en t of recordin g electrodes over th e n erve to be exam in ed. Th ere are two recordin g electrodes, an active electrode an d a referen ce electrode. As both electrodes record electrical waveform s, attention to electrode placem en t is vital. Th e active electrode is placed over th e n erve. Th e referen ce electrode is placed distally on the nerve 3 to 4 cm from the active electrode. An electrical stim ulus from the stim ulator probe is applied to th e nerve at a m easured distan ce from th e active electrode. The electrical waveform produced is known as th e sensory nerve action potential (SNAP). Th e SNAP waveform represen ts th e sum m ation of th e in dividual sen sory action poten tials stim ulated. Th e waveform h as th e followin g param eters: onset latency, peak latency, amplitude, duration, an d conduction velocity(Fig. 4.1). Norm al values are available for laten cies at defin ed distan ces an d amplitudes for specific sen sory n erves. Con duction velocity is calculated by dividin g th e distan ce traveled by th e electrical stim ulus by th e on set laten cy.

Figure 4.1 Sensory nerve action potential (SNAP). The SNAP is

usually biphasic or triphasic in configuration. Latencies are measured in ms. Amplitudes are measured in µ V. (From Preston DC, Shapiro BE. Electromyography and Neuromuscular Disorders. 2nd ed. Philadelphia, PA: Elsevier, Butterworth-Heinemann, 2005, with permission.)

Th is simple calculation can n ot be used with respect to m otor NCS as will be discussed later. Norm al con duction velocities tend to be greater than 48 m per second for upper lim b studies an d greater than 39 m per second for lower lim b studies.

Motor NCS Motor NCS are perform ed by placem ent of the active electrode over the m otor endplate, usually the center of the m uscle belly. The reference electrode is placed distally over an in active point such as the tendon insertion. Th e peripheral n erve is stim ulated at a m easured poin t proxim ally. Th e waveform produced is kn own as th e compound muscle action potential (CMAP). The CMAP is the sum m ated electrical activity from depolarization of m uscle fibers un der th e active electrode. Th e m ost com m on param eters an alyzed include onset latency, amplitude, duration, and conduction velocity (Fig. 4.2). Norm ative data are available for latencies an d amplitudes. Th e complexity of th e m otor on set laten cy m akes m easurem en t of m otor con duction velocities less straightforward than m easurem ent of sensory conduction velocities. Sim ply dividin g th e distan ce traveled by th e electrical stim ulus by th e on set laten cy will n ot produce an accurate con duction velocity because of th e variability in the neurom uscular junction tim e. To calculate a m otor conduction velocity, the nerve m ust be stim ulated at two differen t sites, distal an d proxim al. Th e on set laten cy from th e distal stim ulation is subtracted from th e on set laten cy of th e proxim al stim ulation. This “subtracts’’ out the neurom uscular transm ission tim e, as well as the latency of activation, leaving the action potential tim e between the two stim ulation poin ts. Th e con duction velocity is calculated by dividin g th e

Figure 4.2 Compound muscle action potential (CMAP). The

CMAP is biphasic. Latencies are measured in ms. Amplitudes are measured in millivolt. (From Preston DC, Shapiro BE. Electromyography and Neuromuscular Disorders. 2nd ed. Philadelphia, PA: Elsevier, Butterworth-Heinemann, 2005, with permission.)

Chapter 4: Electrodiagnostic Testing

distan ce between th e two stim ulation poin ts by th e action poten tial tim e between th e poin ts. Norm al con duction velocities tend to be greater th an 48 m eters per second for upper lim b studies an d greater th an 39 m eters per secon d for lower lim b studies.

Late Responses In addition to sen sory an d m otor con duction studies, late responses can be obtained to assess the proxim al portions of the nerves. Late responses include F-waves an d H-reflexes. Th eses waveform s in volve an action poten tial travelin g proxim ally to th e spin al cord an d th en distally to th e recordin g electrodes. F-waves on ly in volve m otor n euron s. Th ey are late m otor respon ses th at occur after th e CMAP. Th ey were first n oted in the foot m uscles, hence th e nam e, F-wave. F-waves can be elicited from any n erve th at h as m otor axon s. Active an d referen ce electrodes are placed th e sam e way as for a m otor con duction study. An electrical stim ulus is applied to th e n erve distally. A supram axim al stim ulus is used. A CMAP (also kn own as th e M-wave) is produced when the action poten tial travels from th e stim ulation site distally to the recording electrodes. The F-wave is produced from the action poten tial th at is travelin g in th e opposite direction . Th is action poten tial travels to th e an terior h orn cells at the spinal cord. A sm all proportion of the an terior h orn cells will “backfire,’’ resulting in an action poten tial that will travel back down th e n erve to th e recordin g electrodes, and produce an F-wave (Fig. 4.3). F-waves ten d to be sm all (1% to 5% of CMAP amplitude). Th ey also vary in laten cy. For th is reason , at least

Figure 4.3 F-wave. The course of the depolarization following

stimulation (dot) is shown by the arrows. Initially, depolarization travels both directly to the muscle fibers, producing the M-wave, and in a retrograde fashion up the axon to the neuron, where the excitation of the neuron causes “backfiring” in a small percentage of neurons (randomly occurring), resulting in an action potential returning back down the axon to produce the delayed F-wave. The trace below shows a recording of the M-wave and F-wave. (From Pease WS, Lew HL, Johnson EW. Johnson’s Practical Electromyography. 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2007, with permission.)

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10 F-waves are obtain ed an d th e fastest waveform (F-wave m inim um , or F-wave m in ) is chosen. Norm ative data are available for specific nerves and differen t leg length s (heights). F-waves are usually perform ed bilaterally, and side-to-side differen ces are evaluated. Norm al side-to-side differen ces are less th an 2.0 m s for th e upper lim bs an d less th an 4.0 m s for th e lower lim bs. Although F-waves are used to assess the m ore proxim al portion s of th e n erves, th eir diagn ostic utility is lim ited. Wh ile th ey are h elpful in diagn osin g gen eralized n europath ic processes th at m ay affect proxim al n erve segm en ts such as polyneuropath ies and polyradiculopath ies (i.e., Guillain -Barré Syn drom e), th ey are of m in im al use with radiculopath ies an d plexopath ies. F-wave lim itation s are related to m ultiple factors. F-waves require on ly a few in tact fast fibers for th e F-wave m in respon se to be n orm al. As m ost m uscles are in n ervated by two or m ore n erve roots, sin gle n erve root abn orm alities usually result in a norm al F-wave m in . Sin ce F-waves in volve on ly m otor fibers, a sensory radiculopathy will result in a norm al F-wave m in . F-waves test lon g segm en ts. Un less th e path ology is severe, th e abn orm alities m ay be “diluted out’’because of th e lon g distan ce assessed. Sin ce F-waves in volve n ot on ly th e proxim al n erve segm ent but also the distal, an abnorm al F-wave m in alon e will n ot localize th e lesion . For example, a patien t with a m edian neuropathy at the wrist can have a delayed m edian F-wave due to slowin g of th e F-wave across th e carpal tun n el. On the other han d, an abn orm al F-wave with n orm al distal m otor con duction studies does suggest a proxim al lesion . For in stance, if th e m edian m otor conduction studies are completely norm al, but the m edian F-waves are delayed or absen t, th is would suggest a lesion m ore proxim ally. Hoffm an first described the H-reflex in 1918. This is a late response that has sensory afferen t and m otor efferent com pon en ts, an d is th us a true reflex. In adults, th e Hreflex is typically obtain ed with stim ulation of th e tibial n erve wh ile recording over th e gastrocn em ius/soleus m uscle. For th e tibial H-reflex, th e active electrode is placed over th e gastrocn em ius m uscle (th e poin t th at bisects th e lin e from popliteal fossa to the m edial m alleolus). Th e reference electrode is placed over th e Ach illes ten don . An electrical stim ulus is applied to the tibial n erve at the popliteal fossa. Th e optim al stim ulus is a long-duration, submaximal stim ulus. This type of stim ulus will selectively activate Ia afferent sensory fibers. Th e action poten tial will travel along the sensory n erve to the spinal cord, traverse a syn apse to th e m otor neuron, travel down the m otor n erve to the recording electrodes, and produce the waveform kn own as th e “H-reflex” (Fig. 4.4). The type of stim ulus is vital. Too sm all a stim ulus will n ot produce a respon se. Too h igh a stim ulus will extin guish th e H-reflex an d produce an F-wave. Un like th e F-wave, th e H-reflex tends to be larger (can be as large as th e CMAP) an d is of con stan t laten cy. For this reason, it is not necessary to obtain 10 or m ore waveform s. As with the F-wave, th e H-reflex can be used to assess

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Figure 4.4 H-reflex. The response is obtained

with stimulation (open dot) of the afferent sensory fiber (top). A long-duration, low-amplitude stimulus selectively activates the sensory afferents. A few motor fibers are usually activated as well, producing a rudimentary M-wave. The action potential travels along the sensory fiber (top) to the spinal cord, synapses with the motor neuron, and then travels back down the motor fiber (bottom) to the muscle, producing the H-reflex. (From Pease WS, Lew HL, Johnson EW. Johnson’s Practical Electromyography. 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2007, with permission.)

the proxim al portions of th e nerve. Its diagn ostic utility is sim ilar to th at of F-waves with respect to polyn europathy and polyradiculopathy. Uniquely, the H-reflex can be used to evaluate S1 radiculopath ies as th e tibial H-reflex is prim arily m ade up of S1 fibers. Th e lim itation s of th e H-reflex are sim ilar to th ose of the F-wave, alth ough on e advan tage of th e H-reflex is th at it in volves sen sory as well as m otor fibers. F-waves on ly in volve m otor fibers. A S1 sen sory radiculopathy m ay result in an abnorm al tibial H-reflex, whereas the rest of th e electrodiagn ostic testin g will be norm al. As with F-waves, perform ing bilateral studies is th e stan dard. A side-to-side differen ce of greater th an 1.5 m s is con sidered abnorm al. Norm al values for H-reflex laten cies are depen den t on age an d leg len gth .

Repetitive Nerve Stimulation RNS is prim arily used to assess n eurom uscular jun ction disorders. Th e tech n ique is sim ilar to a m otor con duction study, except th at in th is study 5 to 10 successive supram axim al stim ulation s are applied. Multiple CMAPs are produced an d usually displayed on th e sam e baselin e. In n orm al subjects, RNS at 2 to 3 Hz will produce CMAP waveform s with con stant amplitude (Fig. 4.5). In a patien t with a n eurom uscular jun ction disorder, a gradual reduction in th e CMAP amplitude is often seen , an d th is is known as a “decrem ent.” Th is decrem ent can be accen tu-

Figure 4.5 Repetitive nerve stimulation (RNS) at 3 Hz in a normal subject. In this example, five successive motor nerve stimulations were performed and recorded. In normal subjects, the amplitude should change minimally or not at all. (From Preston DC, Shapiro BE. Electromyography and Neuromuscular Disorders. 2nd ed. Philadelphia, PA: Elsevier, Butterworth-Heinemann, 2005, with permission.)

ated usin g exercise or high-frequen cy RNS. Exercise (10 to 15 second isom etric contraction) or h igh -frequency RNS (20 to 50 Hz) results in calcium build-up at the axon nerve term in al. Wh en RNS at 2 to 3 Hz is perform ed im m ediately after exercise or high-frequency RNS, the CMAP amplitude enlarges temporarily. This is kn own as “facilitation.” Th e RNS at 2 to 3 Hz is repeated every 1 m in ute for 5 to 6 m inutes. In a patient with a neurom uscular jun ction disorder, th e decrem en t will be n oticeably accen tuated, kn own as “postexercise exh austion” (Fig. 4.6). The pattern of the decrem en t, facilitation , an d postexercise exh austion can h elp determ ine wh ether th e n eurom uscular jun ction disorder is postsyn aptic (i.e., myasth en ia gravis) or presyn aptic (i.e., Lam bert-Eaton myasthenic syndrom e).

NCS PITFALLS Electrodiagn ostic m edicin e is wrough t with pitfalls, som e related to in h eren t lim itation s of th e testin g itself an d also to tech n ical factors. As n oted previously, NCS an d EMG sh ould be used as an extension of a focused history an d physical exam in ation . Too frequen tly, testin g is n ow bein g perform ed by tech n ician s with out electrodiagn ostic physician s’direct supervision or involvem ent. This often results in excessive testing and erroneous diagnoses. The lim itations of NCS and EMG vary depending on the specific disease processes an d diagn oses bein g evaluated. With respect to tech n ical factors, th ere are m any. Today’s autom ated electrodiagnostic equipm ent requires m inim al instrum entation adjustm ents. Alth ough this improves the ease of testin g, on e m ust be careful as n orm ative data are based on specific NCS an d EMG tech n iques usin g specific instrum ent settings and electrode placem ent. Perform ing testin g usin g differen t filter settin gs, sweep speeds, an d sensitivity can affect the waveform m orphology and/or the m easurem ent of the waveform param eters. Attention n eeds to be m ade with respect to active an d referen ce electrode placem ent in accordance with the NCS technique described. For NCS, distan ce m easurem en ts are perform ed with a sim ple tape m easure. Care m ust be taken to m ake precise m easurem en t to reduce latency and calculated conduction


Figure 4.6 Postexercise facilitation and exhaustion in a patient

with myasthenia gravis. Three-Hz RNS is performed. A: Decrement of compound muscle action potential (CMAP) amplitude at rest. B: Postexercise facilitation. Decrement of CMAP immediately following 10 seconds of maximal voluntary exercise has repaired toward normal. C–E: Postexercise exhaustion. Decrements of CMAP 1, 2, and 3 minutes after the previous exercise. Decrement becomes progressively more marked over the baseline decrement. (From Preston DC, Shapiro BE. Electromyography and Neuromuscular Disorders. 2nd ed. Philadelphia, PA: Elsevier, Butterworth-Heinemann, 2005, with permission.)

velocity errors. Over shorter in terstim ulus distances, m easurem en t errors produce significantly higher conduction velocity calculation errors. Physiologic factors such as age, tem perature, lim b length/ heigh t, and anom alous innervations influence NCS an d EMG. With respect to age, newborns have nerve conduction velocities on e-h alf of n orm al adult con duction velocities. At the age of 3 to 5 years, conduction velocities reach adult values. After th e age of 50 years, conduction velocities drop 1 to 2 m per secon d per decade because of loss of large axons and segm ental demyelination / remyelin ation . With advan cin g age, n erve con duction amplitudes declin e as well. Compared with 18- to 25-year-

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olds, SNAP am plitudes can be reduced by on e-h alf in 40- to 60-year-olds, and by two-thirds in 70- to 88-year-olds. This is of particular importan ce with lower lim b SNAP amplitudes as th ey are n orm ally sm all to begin with . For exam ple, n orm al sural an d superficial peron eal SNAP amplitudes m ay be as sm all as 6 to 10 uV. A 2- to 3-uV respon se in an 80-year-old subject m ay be difficult to record because of lim itation s of th e in strum en tation . Temperature greatly affects NCS. As n erve temperatures declin e, laten cies becom e prolon ged, an d con duction velocities declin e. Th is occurs because of slowin g of sodium ch an n el activation. For every 1 ◦ C drop in temperature, con duction velocity drops approxim ately 1 to 2.4 m per secon d depen din g on th e n erve tested. Declin in g tem peratures also result in slowed sodium ch an n el inactivation, resulting in increased SNAP and CMAP amplitudes. Alth ough correction factors can be used to calculate th e correspon din g laten cy, conduction velocity, or amplitude at a specific temperature, this adds further calculation error to the testing and is not recom m en ded. Th e best tech n ique is to warm th e cold lim b to th e appropriate temperature before perform in g th e NCS. Warm in g m ethods in clude hydroculator packs, runnin g the lim b under warm tap water, infrared lamps, hairdryers, etc. As th e direct n erve temperature is difficult to assess, surface skin tem peratures are used. Optim al surface skin temperature is at least 32 ◦ C for the upper lim bs and at least 30 ◦ C for the lower lim bs. The temperature should be m on itored th rough out th e testin g an d recorded on th e electrodiagn ostic report. O verdiagn osis, particularly wh en evaluatin g polyn europathy, can occur if adequate tem peratures are not m aintained. Lim b length affects conduction velocity. Longer lower lim bs (greater height) tend to have slower conduction velocities. The reduction in conduction velocity is th ought to be due to declin in g axon diam eters at un iform distan ces from the anterior horn cell. Upper lim b length does not seem to affect con duction velocity; however, lower lim b con duction velocities ten d to be slower th an uppers, also likely due to sm aller axon diam eters in the lower lim bs com pared with th e uppers. Anom alous in nervation m ay lead to NCS and EMG m isdiagn osis. Th ese an om alous in n ervation s are m ore appropriately term ed “an atom ical varian ts” as th e m ore com m on ones can occur in up to 30% of the population . In the upper lim bs, th e Martin-Gruber anastomosis is autosom al dom inan t with in cidence up to 34% and is bilateral in up to 68%. It involves a conn ection of m edian m otor fibers to ulnar m otor fibers in th e forearm . Th e an atom ic con n ection usually occurs th rough a bran ch of th e m edian n erve, the an terior in terosseous n erve. Th e an astom osis supplies th e first dorsal interosseous m uscle (95% to 100% of the tim e), hypothen ar m uscles (41% to 61% of the tim e), and adductor pollicis (14% of the tim e). Clinically, a patient with a complete uln ar lesion at th e elbow m ay con tin ue to h ave good h and function if th e Martin -Gruber an astom osis occurs.

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Th e Riche–Cannieu anomaly occurs in up to 77% of people. It in volves an an atom ical con n ection of th e m edian an d ulnar nerves in the hand between the recurrent branch of th e m edian n erve an d th e deep bran ch of th e uln ar nerve. The percentage of m edian nerve fibers involved is quite variable. With th is varian t, it is clin ically possible to have an “all ulnar h and.’’ In this case, a patien t with com plete severan ce of th e m edian n erve at th e wrist m ay con tin ue to h ave abductor pollicis brevis an d oppon en s pollicis function. At th e lower lim bs, the accessory deep peroneal nerve has an in ciden ce up to 28% an d when present is bilateral up to 57% of th e tim e. Norm ally, th e exten sor digitorum brevis (EDB) m uscle is innervated by the deep peroneal nerve. In subjects with th e varian t, th e superficial peron eal n erve gives off a branch (accessory deep peroneal nerve) to innervate the EDB. Clinically, a patient with a complete deep peron eal n erve lesion m ay h ave a n orm al EDB EMG an d norm al EDB fun ction.

ELECTROMYOGRAPHY Needle EMG in volves th e use of a fin e n eedle electrode to record electrical activity from m uscles. Th e m ost com m on ly used EMG n eedles are eith er concentric or monopolar. Stan dard con cen tric n eedle electrodes con sist of a h ollow, stainless steel cannula with a cen tral platin um or nich rom e silver wire. The wire is the active electrode and the can n ula serves as the referen ce electrode. Mon opolar needle electrodes con sist of a solid stain less steel n eedle th at is Teflon coated except th e tip. The m onopolar needle serves as the active electrode. A separate referen ce electrode, typically a surface electrode, is required. The recordin g surface area of a m on opolar n eedle is larger th an th at of a con cen tric, resultin g in recorded m otor un it action poten tials (MUAPs) with larger amplitudes, lon ger duration s, an d m ore polyph asia. Mon opolar n eedles are associated with m ore in terferen ce an d backgroun d n oise but ten d to be less expen sive th an concentric needles. Both concentric and m onopolar needles are available in differen t len gth s an d various gauges (23 to 30 gauge). Th e m ajority of electrom yograph ers use sterile disposable EMG n eedles, alth ough som e use n ondisposables an d sterilize th em before each use.

Patient Preparation In gen eral, th e n eedle EMG ten ds to be m ore un com fortable th an th e NCS. It is recom m en ded th at th e patien t be aware th at som e discom fort or pain m ay occur durin g testin g; h owever, m ost patien ts are able to tolerate th e procedure with out problem . Patien t tolerability for electrodiagn ostic testin g is relian t on n um erous factors, in cludin g the individual’s pain tolerance as well as the exam in er’s tech n ique an d ability to keep th e patien t distracted. An algesic or an xiolytic m edication s prior to testin g can be used

but are rarely n ecessary. Topical an algesics are of lim ited ben efit as th e m ajority of discom fort is related to th e n eedle insertion s in the m uscle and not th e skin puncture. Th ere are no absolute contrain dications for perform ing needle EMG; h owever, relative con train dication s in clude coagulopathy (bleeding risk) and lymphedem a (infection risk).

Needle Electromyographic Technique Typically, th e NCS are perform ed before th e n eedle EMG, although in som e cases the needle EMG m ay be m ore useful th an the NCS an d thus perform ed first. The m uscles to be exam in ed via n eedle EMG are determ in ed by th e h istory an d physical exam ination (and the NCS findin gs if already perform ed). Th e basic steps in n eedle EMG are (a) in sertional activity, (b) m uscle at rest to assess for spontaneous activity, and (c) m inim al to m oderate m uscle contraction to assess MUAPs. The electrical activity is evaluated n ot only visually on th e display m onitor but also by sound from the EMG speaker.

Insertional Activity Insertional activity an d muscle at rest are usually evaluated in sam e sequence. The n eedle electrode is inserted into the targeted m uscle wh ile th e m uscle is at rest. Th e patien t’s lim b m ay have to be repositioned to relax it adequately. The n eedle is then quickly in serted furth er in 0.2 to 2 m m in crem en ts with a several secon d pause between in sertion s. Th e n eedle m ovem en t m ech an ically depolarizes m uscle fibers wh ile m oving th rough the m uscle. This depolarization is recorded as bursts of electrical activity th at stop abruptly after n eedle m ovem en t h as stopped. Norm al in sertion al activity h as a duration of less th an 300 m s after n eedle m ovem en t cessation . In creased in sertion al activity h as a duration greater th an 300 m s after n eedle m ovem en t an d can occur in m uscle denervation or myopathy but can be a n orm al varian t. Decreased in sertion al activity is either the absen ce or a sign ifican t reduction of th e electrical bursts with n eedle m ovem en t. This can occur wh en the needle is n ot in m uscle, but in stead in fat or scar tissue. Min im ally, the needle electrode is inserted into four different regions of th e m uscle at th ree differen t depth s.

Muscle at Rest Wh en th e n eedle is bein g in serted, in sertion al activity is assessed. When needle m ovem ent has stopped, the m uscle at rest can be assessed. Electrical activity th at is not due to n eedle m ovem en t or volun tary m uscle con traction is called spontaneous activity. Spon tan eous activity can be n orm al in th e form of miniature endplate potentials (MEPPs) and endplate spikes. Th ese poten tials can be seen wh en th e n eedle electrode is placed close to the m uscle’s endplate region. As these potentials are norm al, and th e m ajority of other types of spontaneous


activity suggest pathology, it is critical to be able to identify MEPP and en dplate spikes. MEPP are th ought to originate from spontaneous release of single quanta of acetylch olin e at the presyn aptic nerve term in al. MEPP have sm all amplitudes and duration, are irregular, and sound like a “seashell.’’ Endplate spikes are m ech anically produced by needle m ovem ent at the en dplate region, resulting in a subthreshold endplate potential. These spikes are larger th an MEPPs; they are rapid and irregular and soun d like “sputtering fat on a fryin g pan .’’ O th er types of spon tan eous activity frequen tly suggest path ology. Th is spon tan eous activity in cludes fibrillation poten tials, positive sh arp waves, complex repetitive disch arges (CRDs), myoton ic disch arges, myokym ic disch arges, fasciculations, cramps, and trem ors. Each waveform has a distinct appearance and sound. Fibrillation potentials an d positive sharp waves are often observed together. Alth ough th ey h ave different appearances, their clinical significance is thought to be sim ilar. Fibrillations are usually biph asic or triphasic (initial downward deflection ), of sh ort duration , of 20 to 1000 uV am plitude, an d usually have regular rhyth m . Th ey sound like “rain on a tin roof.’’ Th e amplitude of a fibrillation potential tends to dim in ish with tim e. For example, fibrillation size in th e first m on th can be up to 1000 uV. After on e year, th e size is usually less than 100 uV. Positive sharp waves are usually biphasic (large in itial downward deflection, followed by long upward deflection), have less than 1000 uV amplitude, and are regular (Fig. 4.7). Fibrillations an d positive sh arp waves can occur in both neuropathic and myopath ic processes. In a n europath ic process with m otor axon loss an d Wallerian degeneration, m uscle fibers becom e denervated. Th e den ervated m uscle fibers can spon tan eously produce action poten tials from sin gle m uscle fibers. Th ese are known as “fibrillation poten tials.” There is controversy on th e origin of positive sh arp waves, but m ost believe th ey

Figure 4.7 Fibrillation potentials and positive sharp waves. A: Biphasic and triphasic fibrillation potentials (f) recorded in denervated muscles. B: Positive sharp waves (p) recorded form the same muscle. (From Dumitru D, Amato AA, Zwarts M. Electrodiagnostic Medicine. 2nd ed. Philadelphia, PA: Hanley & Belfus, 2002, with permission.)

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are sim ilar to fibrillation s except that they require deform ation of a m uscle fiber by the needle electrode. Fibrillation s an d positive sh arp waves can also occur in prim ary m uscle disease. In a myopath ic process th at results in segm ental m uscle necrosis, portions of th e m uscle fiber m ay lose con n ection from th e term in al axon an d becom e “den ervated.’’ O th er m yopath ic processes th at in volve significant inflam m ation an d m uscle fiber splittin g can result in sim ilar den ervation of sin gle m uscle fibers. Metabolic processes that affect m uscle can m ake the resting m uscle m em brane potential unstable an d also produce fibrillations and positive sh arp waves without denervation. CRDs are h igh -frequen cy disch arges th at ch aracteristically start an d stop abruptly. Th ey are m ade up of a run of m ultiple spikes th at repeat regularly at a rate of 20 to 150 Hz. CRDs are th ough t to occur from eph aptic con duction along dam aged m uscle tissue. They are seen in m uscles wh ere th ere h as been ch ron ic den ervation an d rein n ervation, such as certain myopath ies and chronic neuropath ies. Th ey distin ctly h ave a “m otorboat or m otorcycle’’soun d. Myotonic discharges are seen in myoton ic disorders, certain myopathies, and occasionally in ch ron ic neuropath ies. Th ey origin ate from alteration s with th e m uscle m em bran e ion channels. Ch aracteristically, th ey wax and wane with respect to amplitude an d frequen cy, givin g th em a “dive bom ber’’type sound. Clinical myokym ia is seen as a rippling m ovem ent of the skin . Myokymic discharges occur as rhyth m ic bursts of discharges at a frequency of 0.1 to 10 Hz. Th e bursts are m ade of a single m otor unit firin g up to 60 Hz. The rhyth m is very regular, producing a soun d that has been described as “m archin g soldiers.’’ Myokym ic disch arges likely originate from eph aptic con duction alon g dam aged axon s. Lim b myokym ia is classically seen in radiation -in duced plexopathy. As expected, th e in ciden ce of radiation plexopathy in creases with th e dose of radiation delivered. Th e on set of radiation plexopathy varies from a few m on th s to several years after exposures. Facial myokym ia is m ost com m on ly seen in brain stem n eoplasm , m ultiple sclerosis, an d Bell’s palsy. Fasciculation s are clinically visible as spontaneous in term ittent con tractions of m uscle. Fasciculation potentials appear as norm al MUAPs but are very irregular. Voluntarily activated MUAPs fire in a regular fashion an d not any slower th an 4 to 5 Hz. Fasciculation s fire at frequen cies between 0.1 an d 10 Hz, but usually less th an 2 Hz. Th ey can be benign and found in the norm al population, particularly following fatigue, h eavy exercise, or caffein e. Path ological fasciculation s are seen in m otor n euron disease such as amyotrophic lateral sclerosis, as well as lower m otor neuron diseases. There is no reliable way to distinguish “benign’’ from “m align an t’’ fasciculation s. However, fin din g fasciculation potentials with other types of abn orm al spon tan eous activity (i.e., fibrillation s an d positive sh arp waves) and abnorm al volun tary MUAPs would suggest that observed fasciculation poten tials are path ological.

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Cramps are sustain ed m uscle con traction s lastin g secon ds or m in utes. Th ey can be n orm al, or in duced by electrolyte im balan ces, m etabolic disorders, or isch em ia. Cramp discharges on needle EMG appear as m ultiple m otor un its firin g in syn ch rony at 40 to 60 Hz. Th ey usually h ave an abrupt onset and cessation but can fire irregularly in a sputtering fashion, especially just before term in ation . Atrem or can occur durin g volun tary m uscle con traction but also can occur spon tan eously with th e m uscle at rest. Tremor on needle EMG appears as synchronous bursts of MUAPs. Trem or sounds sim ilar to myokym ia (“m arching soldiers’’); h owever, the in dividual bursts within a trem or are composed of m any different m otor units, wh ereas myokym ic bursts are m ade up of th e sam e m otor un it firin g repetitively.

Minimal to Moderate Contraction to Evaluate Motor Unit Action Potentials Motor un its are assessed with n eedle EMG. A m otor un it consists of an an terior h orn cell, its peripheral nerve, and all sin gle m uscle fibers in n ervated by th at n erve. After assessin g for spontan eous activity, volun tary MUAPs are evaluated. A MUAP represen ts th e sum m ated electrical activity of all sin gle m uscle fibers belon gin g to on e m otor un it th at are close en ough to th e n eedle electrode to be recorded. Th e n eedle is position ed in th e targeted m uscle an d th e patien t is asked to sligh tly con tract th e m uscle. Th e n eedle position is adjusted so th at th e recordin g surface of th e electrode is very close to th e m uscle fibers of th e MUAPs bein g assessed. Th is is n oted by a sh ort MUAP rise tim e or MUAPs th at soun d crisp an d sh arp. MUAP parameters an d recruitment are then assessed. Com m on ly assessed MUAP param eters in clude amplitude, duration, an d phases (Fig. 4.8). As n oted previously,

th e ran ge of n orm al for th ese param eters is differen t with m onopolar versus concentric n eedles. Amplitude is m easured from th e h igh est peak to the lowest peak (m axim um peak-to-peak distan ce). MUAP am plitude is affected n ot on ly by th e n um ber of m uscle fibers in th e m otor un it but also by the distance of the n eedle from the m uscle fibers bein g recorded, th e diam eter of th e m uscle fibers, an d th e synch rony of m uscle fiber firing. MUAP amplitudes typically are greater th an 100 uVan d less th an 3 m V. Abn orm al MUAP amplitudes occur in neuropathic and myopathic processes an d are tim e depen den t. Duration best reflects th e n um ber of m uscle fibers with in a m otor un it. Norm al duration is 5 to 15 m s. Sh ort-duration MUAPs are classically seen in myopathic disorders. Most MUAPs h ave two to four ph ases. A phase is defined as the segm ent of the waveform above or below the baselin e. The total num ber of phases can be easily visualized or determ in ed by coun tin g th e n um ber of baselin e crossings an d addin g one. The num ber of phases is dependent on th e syn ch rony of m uscle fiber firin g with in a MUAP. A MUAP with m ore than four phases is considered polyphasic. Norm al m uscles can h ave 15% to 35% polyph asic MUAPs depen din g on n eedle type. High er percen tages of polyph asia m ay sign ify m uscle denervation with reinnervation or myopath ic processes. MUAP recruitm en t is assessed with m ild to m oderate con traction of th e m uscle. Recruitm en t can be normal, decreased, or increased. Norm al recruitm ent occurs temporally as well as spatially. When a m uscle is in itially contracted, a MUAP will start firin g regularly at approxim ately 5 Hz. With increased contraction, that MUAP will fire faster. When the MUAP reaches a frequency of about 10 Hz, a second MUAP will start firin g at approxim ately 5 Hz. With furth er con traction, the first MUAP will fire around 15 Hz, the second MUAP at 10 Hz, and the third MUAP at 5 Hz. The m axim al

Figure 4.8 Motor unit action potential (MUAP)

parameters. (From Dumitru D, Amato AA, Zwarts M. Electrodiagnostic Medicine. 2nd ed. Philadelphia, PA: Hanley & Belfus, 2002, with permission.)


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Figure 4.11 Myopathic or increased recruitment. A random loss

Figure 4.9 Normal motor unit action potential (MUAP) recruit-

ment. MUAP A begins firing stably at about 5 Hz. With a minimal increase in force of muscle contraction, MUAP A increases its firing rate to 10 Hz and MUAP B begins firing at 5 Hz. With further contraction, MUAP A fires at 15 Hz, MUAP B fires at 10 Hz, and new MUAP C begins firing at 5 Hz. The same process continues as MUAP D is activated. (From Dumitru D, Amato AA, Zwarts M. Electrodiagnostic Medicine. 2nd ed. Philadelphia, PA: Hanley & Belfus, 2002, with permission.)

firin g rate for a MUAP is about 30 to 50 Hz. Th is sequen ce of even ts is kn own as “n orm al MUAP recruitm en t” (Fig. 4.9). Reduced recruitm en t occurs in neuropathic disorders. Reduced MUAP recruitm en t will be seen as a “few MUAPs firin g rapidly’’ in stead of th e n orm al pattern . In a n europath ic disorder, eith er axon loss or demyelin ation can cause dysfun ction of certain MUAPs. With m uscle con traction , the first MUAP will fire regularly at 5 Hz. With further con traction, the first MUAP will in crease in frequency to 10 Hz. Th is is wh en th e secon d MUAP sh ould com e in . In a n europathic disorder, th is second MUAP, and poten tially the third MUAP (etc.), will not fire. The first MUAP keeps increasing its firing frequency th ough. It m ay reach 20 to 30 Hz before th e n ext MUAP fires (if an oth er on e fires at all) (Fig. 4.10). Increased or early recruitm en t occurs in myopath ic disorders. In myopath ic disorders, th e MUAPs m ay be in tact; however, the m uscle fibers are dysfunctional. In th is case, the patient contracts the m uscle, the first MUAP fires at 5 Hz, but the force produced by this MUAP is m uch less than th at anticipated due to the myopath ic process. For this reason, the second MUAP will fire im m ediately with th e first. Th e secon d MUAP also produces m uch less force than expected, so the third MUAP activates im m edi-

Figure 4.10 Neuropathic or reduced recruitment. In this case,

motor unit action potential (MUAP) B and C are not present due to a neuropathic process. MUAP A begins firing at 20 Hz because MUAP B and C are not available. When motor unit A fires at 30 Hz, MUAP D finally becomes activated at 20 Hz. With neurogenic recruitment, fewer motor units are firing at higher than anticipated rates. (From Dumitru D, Amato AA, Zwarts M. Electrodiagnostic Medicine. 2nd ed. Philadelphia, PA: Hanley & Belfus, 2002, with permission.)

of muscle fibers results in each motor unit containing a smaller complement of muscle fibers. For a given force output, therefore, more individual units must fire earlier and faster than normal. With initial muscle contraction, multiple motor units fire immediately. From Dumitru D, Amato AA, Zwarts M. Electrodiagnostic Medicine. 2nd ed. Philadelphia, PA: Hanley & Belfus, 2002, with permission.)

ately as well (and th e fourth, fifth, etc. m ay do the sam e). Th is is seen as m ultiple differen t MUAPs firin g sim ultan eously despite m in im al con traction (Fig. 4.11).

Single-Fiber Electromyography Standard n eedle EMG evaluates MUAPs. A MUAP represents th e sum m ated electrical activity of all single m uscle fibers belon gin g to on e m otor unit that are close enough to the n eedle electrode to be recorded. Single-fiber EMG (SFEMG) can evaluate the electrical activity from individual m uscle fibers. A SFEMG n eedle electrode is m ade up of stain less steel cann ula with a central platinum wire sim ilar to a standard con centric needle; however, the wire exits through a side port of the cannula, resulting in a very sm all recordin g surface (25 µ m ). Th is allows th e n eedle to record from sin gle m uscle fibers. Fiber density an d jitter are an alyzed with SFEMG, which has been used to better un derstan d m otor un its in myopathy an d n europathy. Diagnostically, it is prim arily used to assess neurom uscular jun ction disorders. Th is tech n ique is tech n ically dem an ding and n ot routinely perform ed by the m ajority of electrodiagn ostician s. Fiber density is the n um ber of sin gle m uscle fibers from th e sam e m otor un it with in th e uptake of th e n eedle electrode. In norm al hum an m uscles, very few m uscle fibers from the sam e m otor un it are adjacent to each other. In con dition s with m uscle den ervation followed by rein n ervation by collateral sproutin g, m ore m uscle fibers from the sam e m otor unit can end up adjacent to each oth er. This results in in creased fiber den sity, wh ich can be assessed by SFEMG. Norm ative values for fiber density exist for various m uscles and age groups. With advancing age, especially after the sixth decade, fiber density gradually increases because of den ervation / rein n ervation . Jitter is the tim e variation between sin gle m uscle fiber poten tial pairs. Th e variability is n orm ally between 5 an d 60 m icrosecon ds. Th e SFEMG n eedle is position ed in a m uscle (usually the extensor digitorum com m un is), so that two different single m uscle fiber action potentials can be recorded at th e sam e tim e. Approxim ately 50 to 100 tim e in tervals per pair an d 20 differen t pairs are recorded. Norm al values are available for specific m uscles and age groups. In patien ts with n eurom uscular jun ction disorders, th e tim e

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variability between th e two single m uscle fiber action poten tials (jitter) in creases. In creasin g jitter can result in failure of n eurom uscular tran sm ission an d absen ce of th e secon d m uscle fiber action poten tial of th e pair. Th is is kn own as “blockin g.” SFEMG is th e m ost sen sitive test in th e diagn osis of myasthenia gravis (MG). As SFEMG is technically dem anding, it is best used if RNS an d acetylch olin e an tibody test results are n orm al in a patien t with suspected MG. Alth ough in creased jitter is quite sensitive in testing for n eurom uscular jun ction disorders, it is n ot specific. It can also be seen in neuropath ic and myopath ic disorders.

NERVE REACTION TO INJURY Regardless of th e cause of in jury, th ere are two basic path ophysiologic respon ses to n erve in jury: demyelination or axon

loss. With a nerve injury causing focal demyelin ation only, the dam age stays at the site of injury. The nerve proxim al and distal to the injury site rem ains norm al. Across the site of injury, a phen om enon known as “con duction block” occurs. Con duction block is failure of a n erve im pulse to propagate th rough a portion of structurally in tact axon. With axon loss, Wallerian degeneration will occur. Th e axon dies from th e poin t of in jury an d th en will, over the next several days, die distally, resulting in denervation of m uscle or skin . Th ese processes can be assessed with NCS an d EMG. A com m on classification sch em e for peripheral injuries is the Seddon classification. It divides n erve injuries into neurapraxia, axonotmesis, an d neurotmesis. Neurapraxia involves focal demyelination (con duction block) on ly. If neurapraxia is very sh ort lived, it is th ough t to occur from focal ischem ia. As no axon dam age has occurred, no Wallerian degen eration will follow. Recovery ten ds to be spon tan eous

Figure 4.12 Conduction block. In a normal motor nerve (top), the compound muscle action po-

tential (CMAP) amplitude and morphology usually is similar between distal and proximal stimulation sites. When focal demyelination has occurred (bottom), the distal CMAP amplitude and morphology remains the same; however, the proximal CMAP drops in amplitude and the area becomes dispersed. (From Preston DC, Shapiro BE. Electromyography and Neuromuscular Disorders. 2nd ed. Philadelphia, PA: Elsevier, Butterworth-Heinemann, 2005, with permission.)


(hours to m onths). With axonotmesis, there is axon loss with a variable am ount of supporting tissue dam age. Wallerian degen eration occurs. Th e success of axon recovery depen ds on th e am oun t of in tact supportin g tissues. Neurotmesis, also known as a complete injury, in volves severance of the nerve (axons and supportin g tissue structures). Wallerian degen eration occurs. Progn osis for recovery is very poor. Neurapraxic lesion s in volve focal demyelin ation . On m otor and sensory NCS, this is seen as a blockage of nerve impulses across th e lesion site. The amplitude of the response is m uch sm aller when testing across the lesion site, then compared with testing distally. This is known as “con duction block.” Altern atively, focal demyelin ation m ay result in slowing of conduction velocity across th e lesion site. Th e followin g figures dem on strate th e effect of con duction block on a m otor n erve con duction study. For exam ple, testing the m edian m otor nerve typically requires placem ent of th e active electrode over th e th en ar em in en ce. A distal stim ulation over the m edian n erve at the wrist an d a proxim al stim ulation over th e nerve at the an tecubital space

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are perform ed. Norm ally, th e CMAP amplitudes produced from the distal an d proxim al stim ulation sites are about the sam e. If focal demyelin ation occurs between the two stim ulation sites, con duction block m ay occur (Fig. 4.12). Any n erve impulse th at h as to pass th rough th e area of focal demyelination will dem on strate conduction block. Nerve im pulses th at do n ot h ave to pass th rough th e in jury site will be n orm al (Fig. 4.13). On n eedle EMG, n eurapraxic lesion s will im m ediately dem onstrate reduced MUAP recruitm ent. Abn orm al spon taneous activity, such as fibrillation s an d positive sh arp waves, will n ot be seen , as Wallerian degen eration will n ot occur. With axonotm esis, Wallerian degeneration occurs over a 3- to 9-day period. Th e axon s die at th e site of in jury, an d then distally. On NCS, the amplitudes of the respon ses will be decreased at all stim ulation sites (Fig. 4.14). On n eedle EMG, decreased MUAP recruitm ent will be seen im m ediately after in jury. Abn orm al spon tan eous activity such as fibrillation s an d positive sh arp waves will be seen aroun d day 7 to day 10.

Figure 4.13 Conduction block location and stimulation site. In these examples, a typical motor

conduction study is performed with stimulating a nerve distally and proximally and recording from a muscle. Top: If a conduction block is present between the usual distal stimulation and the muscle, the CMAP amplitudes will be low at both distal and proximal stimulation sites. Middle: If a conduction block is present between the distal and proximal stimulation sites, a normal CMAP amplitude will be recorded distally, while a reduced CMAP amplitude will occur proximally. Bottom: If a conduction block is proximal to the most proximal stimulation site, the nerve remains normal distally; thus, both proximal and distal stimulation sites produce normal CMAP amplitudes. (From Preston DC, Shapiro BE. Electromyography and Neuromuscular Disorders. 2nd ed. Philadelphia, PA: Elsevier, ButterworthHeinemann, 2005, with permission.)

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Figure 4.15 Neurapraxia. In this example, focal demyelination

Figure 4.14 Axon loss. A: Normal motor nerve conduction stud-

ies (NCS) with distal and proximal stimulation sites producing normal compound muscle action potential (CMAP) amplitudes. B: With axon loss lesions, if enough time has occurred for Wallerian degeneration, CMAP amplitudes will decline at all stimulations sites. Caveat: Notice how this pattern of abnormality could also represent conduction block distal to the most distal stimulation site (see Fig. 4.13, Top). (From Preston DC, Shapiro BE. Electromyography and Neuromuscular Disorders. 2nd ed. Philadelphia, PA: Elsevier, Butterworth-Heinemann, 2005, with permission.)

In complete lesions (neurotm esis), the nerve is com pletely severed. Wallerian degen eration occurs over a 3- to 9-day period. Th e m otor an d sen sory NCS will be absen t both proxim al an d distal to th e in jury site. On n eedle EMG, no active MUAPs will be recruited from th e tested m uscle. Fibrillation s an d positive sh arp waves will be seen aroun d day 7 to day 10. Tim in g of th e electrodiagn ostic study is crucial in evaluatin g n erve in juries. Alth ough eviden ce for focal dem yelination or conduction block can be seen im m ediately after nerve injury, the fin din gs for axon loss an d Wallerian degeneration occur over a 3- to 9-day period. For th is reason , the electrodiagnostic findings for neurapraxia (focal demyelin ation ) versus axon otm esis/ n eurotm esis (axon loss) m ay look identical durin g the first few days of injury. In the followin g illustrations, nerve conductions perform ed im m ediately after injury look th e sam e for severe neurapraxia versus neurotm esis. The difference is noted by day 7 to day 10. No respon se is produced with distal stim ulation for th e neurotm etic lesion . The distal respon se rem ains norm al at all tim es for th e n eurapraxic lesion (Figs. 4.15 and 4.16). Optim ally, perform ing testing im m ediately after injury will give a baseline that can be compared with testing at the 10- to 14-day poin t. From a practical stan dpoin t, waitin g to test at th e 10- to 14-day poin t after in jury would be sufficient. If testing for a radiculopathy, waiting for 4 to 5 weeks

(conduction block) has occurred between the distal and proximal stimulation sites. A: Immediately after injury, the distal amplitude is normal, the proximal amplitude is absent. At this time, it is too early to tell if this is due to conduction block versus axon loss. B: 7 to 10 days after injury. Enough time has elapsed for Wallerian degeneration to occur if axon loss is present. The distal amplitude remains normal; thus, no axon loss has occurred. The proximal amplitude is still absent signifying 100% conduction block. C: Several weeks after injury. There has been partial recovery of the conduction block. The distal amplitude remains normal. The proximal amplitude is reduced but improved. (From Pease WS, Lew HL, Johnson EW. Johnson’s Practical Electromyography. 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2007, with permission.)

Figure 4.16 Neurotmesis or severe axonotmesis. In this exam-

ple, nerve severance or severe axon loss has occurred between distal and proximal stimulation sites. A1 : Immediately after injury, the distal amplitude is normal, but the proximal amplitude is absent. This is the same pattern of response seen in Figure 4.15 A. It is too early to tell if this abnormal response is due to conduction block versus axon loss. B1 : 7 to 10 days after injury, the distal response is now absent due to Wallerian degeneration from severe axon loss. The proximal response remains absent. (From Pease WS, Lew HL, Johnson EW. Johnson’s Practical Electromyography. 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2007, with permission.)


is recom m ended, as evidence for m uscle denervation after Wallerian degen eration can be seen at th e paraspin al m uscles at day 7 to day 10, but m ay not be apparent in distal lim b m uscles for 4 to 5 weeks. Nerve con duction testin g after in jury as outlin ed above will provide in form ation regardin g th e type of lesion an d am ount of axon loss versus demyelin ation present. For severe injuries, serial testing every 2 to 3 m on ths, over a period 6 m onths, m ay be necessary to determ in e if a complete lesion is present. For m ilder injuries, waiting too long after injury to test m ay result in electrodiagnostic findings th at are norm al or m inim ally abnorm al, due to remyelination and collateral sprouting or axon regrowth . Th e am oun t of n erve recovery after in jury depen ds on the severity of injury. As expected, purely neurapraxic lesions h ave the best prognosis with recovery usually with in 3 m onths. Axon loss lesion s recover m ore slowly requiring collateral sprouting and/ or axon regeneration. In collateral sproutin g, nearby intact axon s give off axon “sprouts’’ to rein n ervate m uscle or skin th at h as been previously den ervated. Axon regen eration is a slower process, requirin g growth of axon s at th e site of in jury to even tually reach th e target en d organ . Axon regen eration occurs at an approxim ate rate of 1 m m per day or 1 inch per m onth. Th e effectiven ess of axon regeneration is dependent on th e am oun t of in tact supportin g tissue th at is left. For m otor fiber recovery after axon loss, rein n ervation n eeds to occur with in 18 to 24 m on th s. Beyon d th at tim e, too m uch m uscle fiber atrophy an d fibrosis h as occurred, m akin g rein n ervation im possible. Alth ough sen sory fibers do n ot h ave th is problem of en d organ degen eration , severe sen sory n erve in juries rarely recover fully likely due to in ability of th e sen sory axons to reach the skin.

COMMON CLINICAL APPLICATIONS Electrodiagn ostic testin g is used as a tool for diagn osin g neurom uscular disorders. Although in form ation can be obtain ed regardin g th e cen tral n ervous system , th e m ajority of NCS an d EMGs are used to diagn ose periph eral n ervous system disorders. An atom ically this m ay include an terior horn cells, sensory and m otor roots, brachial and lum bosacral plexuses, periph eral n erves, n eurom uscular jun ctions, an d m uscles.

Mononeuropathies Th e m ost com m on m on on europath ies are m edian n europathy at th e wrist, uln ar n europathy at th e elbow, radial neuropathy at th e h um erus, an d peroneal n europathy at the fibular h ead. Median neuropathy at th e wrist is th e m ost com m on of all m onon europathies. Clinically, it m anifests as carpal tunnel syndrom e. Patients typically com plain of n um bn ess in

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a m edian nerve distribution, pain at th e hand and wrist (an d frequen tly m ore proxim ally in to th e forearm ). Nocturn al sym ptom s com m on ly wake patien ts up at n igh t. Difficultly with fin e m an ipulation m ay occur because of loss of sen sory or m otor fun ction . In severe cases, atrophy of m edian -in n ervated th en ar m uscles will occur. O n exam in ation , th e fin ding of sen sory loss in a m edian n erve distribution , th en ar atrophy/ weakn ess, a Tin el’s sign over th e m edian n erve at th e wrist, an d positive Ph alen ’s m an euver can be seen . Electrodiagnostic testing for m edian neuropathy at the wrist is quite sen sitive. Th e goal is not only to localize the lesion to th e m edian n erve at the wrist but also to determ ine the am oun t of demyelination or axon loss. Many n erve conduction study m ethods exist for assessing carpal tunn el syn drom e. Th e typical testin g in cludes stan dard m edian m otor an d sen sory testin g. Th e uln ar m otor an d sen sory n erves are usually perform ed as well to rule out a polyn europathy. Oth er protocols in volve comparison tests between m edian versus uln ar or m edian versus radial con duction s. Th e m ixed (sen sory an d m otor) palm ar studies comparin g uln ar versus m edian con duction s across th e wrist are also popular an d con sidered quite sen sitive. Th e m ost com m on fin din g with m edian n europathy at th e wrist is slowin g of con duction velocity or a delay of laten cy across the wrist. Less com m only, a drop in amplitude across the wrist occurs. Both findin gs suggest focal demyelination. O n n eedle EMG, if th ere is sign ifican t m otor fiber in volvem en t, reduced recruitm en t can be seen . If m otor axon loss is presen t, fibrillation s an d positive sh arp waves m ay be presen t. Th e testin g sh ould attem pt to con firm a m edian n europathy at th e wrist, determ in e its severity, an d rule out oth er n eurom uscular causes for th e patien ts’ sym ptom s, such as a proxim al m edian nerve lesion , brachial plexopathy, or cervical radiculopathy. Th e secon d m ost com m on m on on europathy is ulnar neuropathy at the elbow. This neuropathy usually occurs with stretchin g or com pression of the uln ar nerve at th e uln ar groove or just distal to th e groove at th e cubital tun n el. Clinically, patients complain of n um bn ess in an uln ar distribution , weakn ess with grip an d pin ch , an d frequen tly pain at th e elbow an d forearm . O n exam in ation , weakn ess of the uln ar in n ervated flexor digitorum profundus to th e fourth an d fifth digits can be n oted if th e patien t tries to m ake a fist. Weakn ess with th e uln ar in n ervated adductor pollicis can be n oted by h avin g th e patien t pin ch a piece of paper between the thum b and the index finger (From en t’s sign ). Sen sory loss at th e fifth digit an d th e uln ar portion of th e fourth digit m ay be detected an d a Tin el’s sign over th e uln ar n erve at th e elbow m ay also be presen t. In a significan t uln ar n europathy at th e elbow, sensation loss will also occur over th e dorsal uln ar h an d. Th is part of th e h an d is in n ervated by th e dorsal uln ar cutan eous n erve, a branch of th e uln ar n erve. As th is branch com es off the ulnar nerve several centim eters proxim al to

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the wrist and does not pass through Guyon’s canal at the wrist, it is not affected by ulnar n europathies at th e wrist but can be affected by an uln ar n europathy at th e elbow. If sign ifican t sen sory loss is n oted in th e m edial forearm , this suggests a lesion m ore proxim al to the elbow. Th e sensation to the m edial forearm is provided by the m edial an tebrach ial cutan eous n erve, wh ich com es off th e m edial cord of the brachial plexus; thus should be spared in an uln ar n europathy at th e elbow. Electrodiagnostic testin g for ulnar neuropathy at th e elbow ten ds to be less sen sitive th an testin g for m edian n europathy at th e wrist. Th is is due to tech n ical lim itation s of the studies available. Milder lesions m ay not be detectable by testing. Severe injuries will dem onstrate electrodiagnostic abn orm alities, but exact localization of th e in jury m ay be difficult. Stan dard testin g in cludes uln ar sen sory, dorsal ulnar cutaneous, and uln ar m otor conduction s. Th e m edian sen sory an d m otor con duction s are com m on ly perform ed as well to rule out a polyn europathy or plexopathy. Th e fin din g of uln ar n erve slowed con duction velocity or a drop in amplitude across th e elbow h elp to localize th e lesion th ere. Un fortun ately, th e error in m easurem ent an d calculating the conduction velocity across the elbow is quite h igh , even with optim al elbow positionin g. A drop in m otor amplitude (con duction block) is useful for localizing th e lesion, but it is often not seen. A drop in sen sory amplitude across th e elbow is difficult to call abn orm al as n orm al temporal dispersion causes a drop in sen sory amplitudes with m ore proxim al stim ulation . Needle EMG m ay be n orm al in m ilder cases. In m ore severe cases, n eedle EMG will dem on strate decreased MUAP recruitm en t an d fibrillation s/positive sh arp waves in ulnar in nervated forearm an d hand m uscles. As there are no uln ar-in n ervated m uscles above th e elbow, th e EMG m ay on ly be able to con clude th at an uln ar n europathy exists proxim al to th e takeoff to th e flexor carpi uln ar m uscle. Th e goals of electrodiagn ostic testin g for uln ar n europathy at th e elbow include localizing the lesion , determ inin g the degree of demyelination versus axon loss, and rulin g out oth er etiologies such as brach ial plexopathy or cervical radiculopathy. The m ost com m on en trapm ent site for the radial nerve is at th e h um eral spiral groove. Th is n erve is quite susceptible to compressive forces an d fractures as it wraps aroun d th e m id h um erus. Patien ts can presen t with a wrist drop an d num bness in a superficial radial sensory distribution . On exam in ation , elbow exten sion sh ould be n orm al as th e triceps receive innervation from the radial nerve proxim ally to the spiral groove. The exception would be triceps’weakness secondary to direct m uscle traum a to the triceps m uscle at the tim e of injury. Radially inn ervated m uscles distal to th e spiral groove such as th e brachioradialis, and fin ger/ wrist exten sors can be weak. Grip stren gth m ay seem weak, but this is due to lack of m echanical advantage from loss of the wrist extensors.

Electrodiagn ostic testin g in cludes radial m otor studies with stim ulation at the forearm , elbow, below spiral groove, an d above spiral groove. A drop in m otor am plitude across the spiral groove signifies conduction block. A drop in con duction velocity is less useful, due to error in m easurem en t. Th e superficial radial sen sory n erve can be abn orm al if th ere h as been sign ifican t axon loss. Needle EMG will dem on strate decreased MUAP recruitm ent. If m otor axon loss is present, fibrillations and positive sharp waves can be seen in radially innervated m uscles distal to th e spiral groove. Goals are to localize th e lesion to the radial nerve at th e spiral groove, rule out radial n europathy at th e axilla, radial n europathy at th e forearm (posterior interosseous neuropathy), an d rule out brachial plexopathy or cervical radiculopathy. Peroneal neuropathy (or fibular neuropathy) m ost com m only occurs at th e fibular head. Th e nerve is susceptible to com pression an d stretch in g th ere. Patien ts typically presen t with a foot drop an d n um bn ess at th e lateral calf an d dorsum of th e foot. At th e fibular head, the com m on peroneal n erve divides in to deep an d superficial bran ch es. Th e clinical presentation will vary depending on how m uch each bran ch is affected. Electrodiagn ostic testin g com m on ly in cludes peron eal m otor con duction s at th e an kle, below th e fibular head, an d above the fibular h ead. The superficial peron eal n erve is tested with stim ulation at th e lateral calf and will be abn orm al in lesions with sign ifican t axon loss. Th e tibial m otor an d sural sen sory con duction s are usually obtained to rule out polyneuropathy or m ore proxim al n europathy. Needle EMG would in clude peron eal inn ervated m uscles of th e lower lim b. To rule out a m ore proxim al lesion, testing tibial innervated m uscles and sciatic innervated ham string m uscles is useful. The sh ort head of th e biceps is particularly useful as it is in n ervated by th e peron eal portion of th e sciatic n erve but above th e fibular h ead. Abnorm alities at this m uscle would place the lesion m ore proxim al to th e fibular head (sciatic nerve, lum bosacral plexus, or lum bosacral radiculopathy).

Polyneuropathies Polyn europathy or gen eralized periph eral n europathy is com m only assessed by electrodiagnostic studies. The differential diagnosis for polyneuropathy is vast. The goal of electrodiagn ostic testin g is to con firm th e presen ce of a polyn europathy and to classify it into a subcategory to n arrow th e differen tial diagn osis. Specifically, th e testing should help determ ine whether the polyn europathy is diffuse or m ultifocal, involves sensory an d/or m otor fibers, an d prim arily in volves axon al loss an d/ or demyelin ation. Polyn europathy can be subdivided by electrodiagn ostic testing in to th e followin g categories: (a) uniform demyelin atin g, m ixed sen sorim otor, (b) segm en tal demyelin atin g, m otor greater th an sen sory, (c) axon loss, m otor greater th an sen sory, (d) axon loss, sen sory, (e) axon


loss, m ixed sensorim otor, and (f) m ixed axon loss, demyelinating, sensorim otor. For in stan ce, acute in flam m atory demyelin atin g polyneuropathy (AIDP) or Guillain-Barré syn drom e would fall un der th e segm en tal dem yelin ation , m otor greater than sensory polyneuropathy category. With segm ental demyelin ation , prom in en t con duction block an d abn orm al temporal dispersion is seen . Alth ough demyelin ation is th e m ain disease process, secondary axon loss can occur. This is important to note as pure axon loss or pure demyelination rarely occurs. Late respon ses such as F-waves an d H-reflexes are frequently useful in assessing polyneuropathies as they evaluate th e m ore proxim al portion s of th e n erves. Late respon ses are particularly useful in AIDP, as th ey are frequen tly absen t early in th e course of th e disease wh ile th e rest of th e electrodiagn ostic testin g rem ain s with in n orm al lim its. Most un iform demyelin atin g polyn europath ies are hereditary. Hereditary m otor sensory neuropathy (HMSN) I or Ch arcot-Marie-Tooth disease falls un der th is category. Th e predom in an t fin din g is decreased con duction velocities with out conduction block or abnorm al temporal dispersion . Th e m ajority of polyn europath ies are prim arily axon al. Th e axon loss m ixed sen sorim otor polyn europathy is th e largest category of polyneuropathy; hence the m ore difficult type of polyneuropathy to determ ine the cause. Causes for axonal polyneuropathies include alcoholism , heavy m etals, toxins, pharm aceuticals, connective tissue diseases, en docrin e disorders, an d n utrition al deficien cies such as B12 , folate, or th iam in e. NCS reveal reduced amplitudes. Slowin g of con duction velocity can occur because of loss of fast con ductin g axon s; h owever, con duction velocity does not drop below 75% of norm al. If m otor axon loss is presen t, n eedle EMG m ay sh ow fibrillation s/ positive sh arp waves and abnorm al MUAPs. A caveat regardin g electrodiagn ostic testin g an d polyn europath ies is th e sm all-fiber polyn europathy. Stan dard electrodiagn ostic testin g assesses large fiber n erves. All m otor n erves are large diam eter fibers; h owever, sen sory fibers can be large or sm all. For th is reason , patien ts with sm all-fiber polyn europathy m ay h ave n orm al electrodiagnostic studies. Fortunately, from a diagnostic stan dpoint, m ost polyn europath ies will affect large an d sm all fibers. However, com m on causes of polyneuropathy such as diabetes m ellitus an d alcoh olism , wh ich usually affect both large an d sm all fibers, can also m an ifest predom in an tly as a sm all-fiber polyn europathy.

Radiculopathies Radiculopathies are disease processes in volvin g th e n erve roots an d m ost com m on ly caused by compression from in tervertebral discs an d/ or osseoligam en tous structures. Although electrodiagn ostic testing ten ds to be sensitive for

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detectin g m on o- an d polyn europath ies, it is less sen sitive for detecting radiculopathies, particularly m ilder ones. The reduced sen sitivity is due to th e n atural course of radiculopath ies an d an atom ical con sideration s. Sen sory NCS are classically norm al in radiculopathies. Th e m ajority of radiculopath ies in volve lesion s proxim al to the sensory dorsal root ganglion (DRG). Dam age to sensory n erve roots proxim al to th e DRG will result in norm al sen sory n erve con ductions, despite clinical sensory loss. For exam ple, a complete lesion (severan ce) of th e left C6 sen sory root proxim al to th e DRG will present as loss of sen sation at th e C6 derm atom e th at includes the thum b. Wallerian degen eration will occur at th e in jury site and distally to th e DRG; h owever, as th e sen sory cell bodies in the DRG rem ain intact, the sensory axons from the DRG an d distally will n ot be affected. Median an d radial sen sory nerve con ductions to the thum b will rem ain norm al, despite th e clin ical sen sory loss. Motor NCS are usually norm al in radiculopathies. The cell bodies for the m otor n erves are located at the anterior h orn of th e spin al cord. Dam age to m otor roots causin g axon loss will result in Wallerian degen eration an d m uscle den ervation . Severe axon m otor axon loss m ay cause a drop in CMAP amplitude. Less sign ifican t axon loss will result in relatively n orm al m otor amplitudes as th e m ajority of m uscles h ave m ulti-root in n ervation . Con duction velocities rem ain n orm al. Th e n eedle EMG is th e m ost sen sitive part of th e electrodiagn ostic study in assessin g radiculopathy. Motor root lesion s with axon loss can produce n eedle EMG abn orm alities such as fibrillation s/ positive sh arp waves, reduced MUAP recruitm en t, an d MUAP waveform abn orm alities. Th e goal is to fin d n eedle EMG abn orm alities in a myotom al pattern, preferably in m uscles innervated by differen t periph eral n erves, an d to fin d paraspin al m uscle abnorm alities. For example, an acute C6 radiculopathy could be diagn osed with fibrillation s/ positive sh arp waves at the following m uscles: cervical paraspin al, biceps (m usculocutan eous, C5-C6), deltoid (axillary, C5-C6), brach ioradialis (radial, C5-C6), pron ator teres (m edian , C6-C7). Norm al rh om boid (dorsal scapular, C5), exten sor carpi uln aris (radial, C7-C8), an d abductor pollicis brevis (m edian, C8-T1) would further support the C6 path ology. Th ere are several pitfalls wh en diagn osin g radiculopathy with electrodiagn ostic testing. Unless there is significant involvem en t of m otor roots, th e n eedle EMG will be n orm al. Focal demyelin ation at a m otor n erve root will n ot result in Wallerian degen eration . On ly if th ere is en ough demyelin ation to cause con duction block will MUAP recruitm en t be affected. Abn orm al spon tan eous activity such as fibrillation s an d positive sh arp waves will n ot occur un less m otor axon loss occurs. An oth er pitfall h as to do with th e n um ber of abn orm al m uscles on n eedle EMG. Frequen tly, even if th ere is m otor

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axon loss, on ly a few m uscles of th e affected myotom e will be abn orm al, m akin g localization to a sin gle root difficult. O ften , even th e paraspin al m uscles will be n orm al. In th is case, a plexopathy cannot be completely ruled out. The m ajority of patien ts wh o presen t with radicular symptom s com plain of pain and sen sory sym ptom s, but n o m otor complain ts. Pain fibers are sm all sen sory fibers th at can not be assessed with routine electrodiagnostic studies. Dam age to sen sory roots ten ds to occur proxim al to th e DRG an d will n ot cause abn orm al sen sory con duction s. If th ere is n o m otor in volvem en t, m otor con duction s an d EMG will be n orm al. Thus, the m ajority of patien ts with this presen tation will h ave n orm al electrodiagn ostic testin g. Cervical an d lum bar radiculopath ies are frequen tly assessed with electrodiagn ostic testin g. Th oracic radiculopath ies are n ot com m on . Testin g for th oracic radiculopath ies is m ore difficult due to th e lim ited m uscles th at can be assessed: thoracic paraspinal, intercostal, and rectus abdom in us. Tim ing affects the electrodiagnostic assessm ent of radiculopathy. Decreased MUAP recruitm en t can be seen early; h owever, detectin g m otor axon loss in th e form of fibrillations and positive sh arp waves m ay take several weeks. Wallerian degeneration typically occurs in 7 to 10 days. Although needle EMG findin gs of fibrillations and positive sh arp waves in th e paraspin al m uscles m ay be seen at day 10 to day 14 , it m ay take 4 to 5 weeks for th ese fin din gs to occur in distal m uscles. Hen ce, testin g too early will produce lim ited fin din gs. Optim al tim in g is 4 to 5 weeks. Testin g too late will also produce lim ited fin din gs due to rein n ervation . Late respon ses, such as F-waves, seem in gly would be useful as th ey assess th e m ore proxim al segm en ts of th e nerve; however, they tend to have a low diagnostic yield in radiculopathy. As described earlier in th is ch apter, H-reflexes can be useful in suspected S1 radiculopathy. Despite th e pitfalls, electrodiagn ostic testin g rem ain s an importan t tool in diagn osin g radiculopath ies. Spin al im agin g for assessin g radiculopathy is kn own to h ave h igh falsepositive rates. Electrodiagn ostic testin g h as m uch lower false-positive rates an d is th e on ly diagn ostic tool able to evaluate th e physiologic fun ction of n erves an d m uscles. In addition to con firm in g a diagn osis of radiculopathy an d determ in in g its severity, electrodiagn ostic testin g will rule out oth er causes for patien ts’sym ptom s such as m on on europath ies an d polyn europath ies.

Plexopathy Brachial and lum bosacral plexopath ies are assessed with electrodiagn ostic testin g in a sim ilar fash ion as radiculopath ies. Th e m ajor differen ce is plexus lesion s typically occur distal to th e DRG. Th erefore, un like radiculpath ies, plexus lesion s with sen sory axon loss will result in abn orm al sen sory n erve con duction s. For in stan ce, a patien t with

a significant upper trunk plexopathy classically will have clin ical sen sory loss at th e lateral forearm an d th e th um b. Median and radial sensory NCS are expected to be abnorm al, unlike our previous example of a C6 radiculopathy. If sign ifican t m otor axon loss h as occurred, m otor NCS m ay reveal decreased amplitudes in m uscles innervated by th e dam aged portion of th e plexus. Th e n eedle EMG can sh ow eviden ce for abnorm al spon taneous activity (fibrillations and positive sharp waves) and/ or abnorm al MUAPs. Paraspin al m uscles sh ould be n orm al, un like radiculopathy. Th e pitfalls for diagn osin g plexopathy with electrodiagn ostic testin g are sim ilar to th ose for diagn osin g radiculopathies. The needle EMG is by the far the best way to diagn ose an d localize a plexus lesion . In a patien t with suspected plexopathy on ly with sen sory deficits, the testing m ay only show abnorm al sensory n erve conductions, m aking localization of the plexus injury difficult. If m otor nerve dam age occurs, but no axon loss, localization will rely on abn orm al MUAP param eters an d recruitm en t, wh ich is m ore subtle to evaluate th an abn orm al spon tan eous activity. Late respon ses such as F-waves an d Hreflexes h ave n ot been foun d to be of sign ifican t utility with diagn osin g plexopathy, due to lim itation s previously discussed.

Other Clinical Applications Electrodiagn ostic testin g is used to evaluate oth er disease processes in cludin g myopath ies, n eurom uscular jun ction disorders, an d m otor n euron diseases. Th e specifics of testing for these disorders go beyond the scope of this chapter an d can be further reviewed with the recom m ended readings listed later.

CONCLUSION Electrodiagn ostic testin g used properly as an exten sion of the clinical history an d exam ination can be an invaluable way to assess neurom uscular disorders. The electrodiagnostic m edicine physician m ust have a strong knowledge base in the disease processes being tested so that the clinical inform ation an d the electrodiagnostic data can be used appropriately. Atten tion to detail with respect to in strum en tation an d testin g tech n ique, is required to reduce errors. Anatom ical variations and electrodiagnostic testing lim itation s n eed to be recogn ized. Improper use of electrodiagnostic testing will lead to m isdiagnosis. Optim al use of electrodiagn ostic testin g can provide a defin itive diagn osis, n arrow th e differen tial diagn oses by con firm in g or ruling out certain types of path ology, h elp localize an d determ in e the severity of lesions, and provide guidance with treatm ent plan s an d progn osis.


REFERENCE 1. AANEM Nom en clature Com m ittee. AANEM glossary of term s in electrodiagn ostic m edicin e. Muscle Nerve. 2001;24(suppl 10):S10 – S11.

RECOMMENDED READINGS Donofrio PD, Albers JW. AAEM m inim onograph #34: polyneuropathy: classification by nerve con duction studies and electrom yography. Muscle Nerve. 1990;13:889 –903.

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Kincaid JC. AAEM m inim on ograph #31: the electrodiagnosis of ulnar n europathy at th e elbow. Muscle Nerve. 1998;11:1005 –1015. Landau ME, Diaz MI, Barner KC, Campbell WW. Changes in nerve conduction velocity across the elbow due to experim ental error. Muscle Nerve. 2002;26:838 –840. Robin son LR. AAEM m in im on ograph # 28: traum atic in jury to periph eral n erves. Muscle Nerve. 2000;23:863 –873. Steven s JC. AAEM m in im on ograph # 26: th e electrodiagn osis of carpal tun n el syn drom e. Muscle Nerve. 1997;20:1477 –1486. Wilbourn AJ, Am in off MJ. AAEM m in im on ograph # 32: th e electrodiagnostic exam ination in patients with radiculopathies. Muscle Nerve. 1998;21:1612 –1631.

Musculoskeletal Infections An drew F. Ku n tz

5

John L. Esterhai

INTRODUCTION Musculoskeletal infections are devastatin g problem s that require sign ifican t tim e an d resources for proper treatm en t. As a group, in fections of the bones, join ts, an d surrounding soft tissues are com m on and h ave the potential to cause significant m orbidity. Treatm en t requires proper diagn osis an d aggressive treatm en t. Surgical in tervention and antibiotic th erapy are th e m ain stays of successful eradication of infection. Delayed or incomplete treatm ent can result in ch ronic pain, deform ity, fun ctional impairm ent, and in the worst case, loss of lim b or even death . Fortun ately, th e later are rare and arrest of infection is typically achievable with appropriate treatm ent.

PATHOGENESIS OF INFECTION Th e h um an body possesses m any defen ses again st th e m ultitude of pathogens that can cause infection. On th e m ost basic level, th ese defen se m ech an ism s in clude physical barriers, in n ate im m un ity, an d th e adaptive im m un e respon se. In con cert, th ese system s protect th e body again st m icroscopic and m acroscopic path ogens. However, a breakdown in any one of these defenses can result in the clinical picture of in fection . Th e skin an d m ucous m em bran es serve as a prim ary barrier to in fection , blockin g th e en try of path ogen s in to the bloodstream an d soft tissues. Even though these physical barriers are extrem ely effective in preventing infection, they are certainly n ot absolute. When infectious m aterial does violate th e skin or m ucus m em bran es, th e in n ate im m un e system is activated. Respon sible for th e signs and symptom s of acute in flam m ation, activation of the in nate

im m un e system in volves recruitm en t of ph agocytic cells, such as n eutrophils and m acroph ages, as well as the initiation of th e com plem en t system . Th e in n ate im m un e system is also respon sible for activation of th e adaptive im m un e system . It is th e adaptive im m une system th at enables the h ost to tailor th e im m un e respon se to a specific pathogen through the involvem ent of T-cells and B-cells. The adaptive im m un e system is also respon sible for im m un ological m em ory. Despite th is com plex series of in tercon n ected defen ses, resistan ce again st path ogen s is n ot perfect, as any on e of these m ech anism s can fail or becom e overwhelm ed. The ability of a m icroorgan ism to overcom e a h ost defen ses is kn own as “virulen ce.” Each an d every organism has differin g degrees an d m ean s of virulen ce. Th e goal of th is ch apter is n ot to review th e virulen ce of differen t m icroorgan ism s. However, it is critical to un derstand that infection in any tissue requires an in oculation of a path ogen or m icroorgan ism in to a tissue with a subsequen t in teraction between the inoculum and th e h ost tissue. In m any cases of infection, it is necessary to understand th e virulence of the offen din g path ogen in order to properly an d defin itively treat th e in fection . In addition to th e virulen ce of a path ogen , local an d system ic h ost factors play a role in th e developm en t of in fection . System ic h ost factors such as ren al an d liver disease, m align an cy, diabetes m ellitus, m aln utrition , alcoh olism , rheum atologic disease, and im m une system dysfun ction all in crease th e risk of in fection . Local tissue factors such as decreased vascularity an d n europathy can also be favorable to th e developm en t of in fection . Both blun t an d pen etratin g traum a can result in comprom ise of local soft tissues as well as form ation of dead space and hem atom a. The presen ce of im plan ts n ot on ly adversely affects ph agocytosis

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but also allows for adh eren ce of m icrobes with subsequen t biofilm form ation . Fin ally, in traven ous drug use results in recurren t episodes of bacterem ia, with a correspon din g in creased risk of local and system ic infection. Staphylococcus aureus is th e m ost com m on causative organ ism of m usculoskeletal in fection s. Over recen t years, S. aureus resistan t to treatm en t with th e an tibiotic m eth icillin (m ethicillin-resistant Staphylococcus aureus or MRSA) has becom e in creasingly m ore com m on. In itially seen on ly in h ealth care–acquired situations, MRSAis now frequently acquired in th e com m un ity as well, with m ore th an 1% of com m unity m em bers testing positive for the bacteria. Recent outbreaks of com m un ity-acquired MRSA skin in fection s h ave been reported am on g ath letes, m ilitary recruits, an d ch ildren . With th e in creasin g prevalen ce of MRSA in the com m unity and hospitals, m usculoskeletal in fections due to MRSA are also m ore com m on . Th is presen ts a specific challenge to th e treating physician as MRSA bacteria have a large num ber of defense m ech anism s. First, an increased num ber of surface proteins facilitate adherence to host tissues and foreign m aterial such as orth opaedic im plan ts. In addition , cell–cell interactions between bacteria allow for quorum sen sin g an d th e rapid production of a protective glycocalyx layer. As a result, MRSA-related in fection s can be extrem ely difficult to treat, with up to h un dred tim es greater an tibiotic resistan ce th an oth er bacteria.

ANTIBIOTICS Antibiotic therapy is param ount in the treatm en t of m usculoskeletal infections. In order for antibiotic treatm ent to be effective, an appropriate regim en m ust be selected. Typically, an tibiotic th erapy begin s with broad coverage, in order to treat th e m ost com m on path ogen s. On ce culture an d sen sitivity data are available, th e an tibiotic regim en should be tailored to th e specific in fection . Th is approach requires knowledge of the m icroorganism s typically responsible for specific infections, as well as th e m ech anism of action an d spectrum of activity for com m on antibiotics. Antibiotics can be broadly categorized into six groups on the basis of their m echan ism of action. The first group of an tibiotics in cludes th ose with activity again st th e bacterial cell wall. Within this group, penicillins and cephalosporins comprise a subgroup of antibiotics collectively referred to as “β -lactam antibiotics.” These antibiotics inhibit bacterial peptidoglycan synthesis via interaction with penicillinbin din g protein s on th e bacterial cell m em bran e. Th e spectrum of activity for th e various β -lactam s is quite broad, alth ough certain an tibiotics with in th e subgroup h ave a narrow spectrum of coverage. β -lactam ase inhibitors are a subgroup of cell wall active antibiotics th at are available in com bination with certain penicillin antibiotics. The com bin ation of th e two types of an tibiotics im proves coverage again st both gram -positive an d gram -n egative organ ism s. Vancomycin is another antibiotic in this group, interfer-

ing with insertion of glycan un its into the cell wall. Vancom ycin h as activity again st En terococcus species, Staphylococcus aureus, an d Staphylococcus epidermidis. It is th e an tibiotic of choice for MRSA and is com m on ly substituted for penicillin or cephalosporin antibiotics in patients with allergies to the β -lactam s. Overall, th is broad group of antibiotics in cludes th e m ost com m only used antibiotics in orth opaedics. Cell wall active an tibiotics are routin ely used as antibiotic prophylaxis in the perioperative period and for defin itive treatm en t of m usculoskeletal in fection s. Th e secon d group of an tibiotics in cludes th ose active against bacterial ribosom es. Within this group, clin dam ycin bin ds to th e 50 S-ribosom al subun it, in h ibitin g dissociation of peptidyl-tRNA from th e ribosom e durin g tran slocation. Macrolide antibiotics (erythromycin, clarithromycin, etc.) function in a very sim ilar m anner. Am in ogylcosides (gen tam ycin , tobram ycin , etc.) bin d to cytoplasm ic ribosom al RNA, th ereby in h ibitin g bacterial protein syn th esis. Th e tetracyclin es (tetracyclin e, doxycyclin e, etc.) also in h ibit bacterial syn th esis, but via in teraction with 70S- and 80S-ribosom es. Togeth er as a group, these antibiotics provide activity against a broad spectrum of path ogen s. Clin dam ycin is un ique am on g all an tibiotics in that it achieves the highest an tibiotic concen tration in bon e, wh ich is n early equal to serum con cen tration s following intraven ous adm inistration. Rifam pin alon e com prises th e th ird group due to its un ique m ech an ism of action . It in h ibits RNA syn th esis in bacteria an d h as a spectrum of action again st m any gram positive an d gram -n egative bacteria. Rifam pin is rarely used alone, as bacterial resistance to rifampin develops rapidly. Th e fluoroquin olon es (ciprofloxacin , levofloxacin , etc.) inh ibit DNA gyrase. All antibiotics in th is group have excellen t gram -n egative coverage. Certain an tibiotics with in the group offer gram -positive an d atypical bacteria coverage. Unique to the fluoroquinolones is the excellen t serum an tibiotic concentrations achieved following oral adm in istration . As a result, treatm ent with these antibiotics is often associated with decreased cost of treatm ent and length of h ospitalization . Antim etabolites are another group of antibiotics, with trim ethoprim -sulfam ethoxazole being the m ost com m on drug in th is group. Trim eth oprim -sulfam eth oxazole is a com bin ation of two an tim etabolites m ost effective wh en given togeth er in fixed com bination. Trim ethoprim binds to bacterial dihydrofolate reductase, in terferin g with folic acid synthesis. Sulfam ethoxazole, a sulfonam ide, inhibits bacterial dihydrofolate syn th etase, wh ich is also n ecessary for th e syn thesis of folic acid. Th erefore, th e two an tim etabolites act synergistically to preven t th e production of folic acid, in h ibitin g bacterial developm en t. Trim ethoprim -sulfam ethoxazole is a broad-spectrum antibiotic that h as excellent coverage against gram -n egative organ ism s an d certain gram -positive bacteria as well. Th e fin al group of an tibiotics in cludes th e reducin g com poun ds. Metron idazole is th e m ost com m on an tibiotic

Chapter 5: Musculoskeletal Infections

TABLE 5.1

ANTIBIOTIC GROUPS AND MECHANISMS OF ACTION Antibiotic Groups and Subgroups Cell wall active β -lactams Vancomycin Ribosome active Clindamycin Macrolides Aminoglycosides Tetracyclines Rifampin Fluoroquinolones Antimetabolites (Trimethoprimsulfamethoxazole) Reducing compounds (Metronidazole)

Mechanism of Action Bind to penicillin-binding proteins on bacterial cell membrane to inhibit peptidoglycan synthesis Interferes with insertion of glycan subunits into the cell wall Binds to 50S-ribosomal subunit, inhibiting dissociation of peptidyl-tRNA from the ribosome during translocation Same as clindamycin Bind to cytoplasmic ribosomal RNA to inhibit bacterial protein synthesis Bind to 70S- and 80S-ribosomes to inhibit bacterial protein synthesis Inhibits bacterial RNA synthesis Inhibit bacterial DNA gyrase Inhibits folic acid synthesis Inhibits anaerobic DNA synthesis via free radical damage to bacterial DNA

in this group. Following uptake by anaerobic bacteria, m etronidazole is reduced to a free radical, which , in turn, dam ages bacterial DNA an d in h ibits DNA syn th esis, ultim ately resulting in cell death . Metronidazole is lethal only for strict anaerobic bacteria that lack protective enzym es. For th is reason , m etron idazole is used n early exclusively for th e treatm ent of in fections caused by anaerobic bacteria. Table 5.1 reviews th e com m on an tibiotic groups an d their m echanism s of action. In addition to an tibiotics’use in th e treatm en t of established m usculoskeletal infections, these are routinely used to preven t in fection s. Prophylactic an tibiotics sh ould be adm inistered within 1 hour before orth opaedic surgery an d for varying length s of tim e postoperatively to reduce the incidence of local an d system ic infection . In m ost instances, including when orth opaedic hardware is implanted, a first-gen eration ceph alosporin given 1 h our preoperatively an d for 24 hours postoperatively is sufficient prophylaxis. Antibiotics are also routinely given in the settin g of open fractures to prevent osteomyelitis and local soft-tissue infection. Generally accepted guidelines include the adm inistration of a first-generation cephalosporin to any patient with an open fracture. In th e setting of a type III open fracture, an am in oglycocide should also be given. The data regarding the need for an am inoglycocide for a type II open fracture is m ixed. Patients with grossly contam inated open fractures sh ould also be covered by the addition of pen icillin .

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Despite th e critical role an tibiotics play in th e preven tion an d treatm en t of m usculoskeletal in fection s, th eir use m ust be m on itored closely, an d lim ited to appropriate situation s on ly, in order to m in im ize th e developm en t of an tibiotic resistan ce. Acquired an tibiotic resistan ce is m ediated by bacterial plasm id DNA. Subth erapeutic dosages, treatm en t courses th at are too sh ort, an d th e use of in effective antibiotics can all lead to resistance. Resistan ce is easily tran sm itted, wh ich m ay, in turn , in crease th e difficulty of treatin g in fection by lim itin g th e spectrum of effective an tibiotics. In recen t years, an tibiotic resistan ce h as been increasin g, due to all of th e reason s previously outlin ed.

DIAGNOSIS OF INFECTION Th e evaluation an d workup of in fection sh ould always begin with a though h istory and physical exam ination. Once an adequate history has been obtained an d a detailed physical exam ination perform ed, radiograph ic an d laboratory studies can aid in th e diagnosis of infection and identification of the causative pathogen. An understanding of the application an d lim itation s of th e various im agin g m odalities and laboratory studies helps in the selection of appropriate tests an d th e practice of cost-effective m edicin e.

IMAGING Radiograph s are relatively in expen sive an d are excellen t in showing bony an atomy, bone chan ges such as resorption and periosteal reaction, and in som e cases soft-tissue swellin g. Radiographs are extrem ely helpful in evaluation for the presen ce and configuration of orthopaedic hardware. Lucen cy at the bone-implant interface can be a sign of in fection , but it can also represen t aseptic loosen in g. Radiograph s effectively dem on strate fractures an d tum ors th at can m im ic in fection on clin ical presen tation . Computed tom ography (CT) is excellent for m ore detailed evaluation of th e m usculoskeletal system , as well as for the assessm ent of three-dim ensional an atomy. CT is useful in m any situation s, but it is particularly im portan t wh en evaluatin g for fracture un ion in th e settin g of in fection, and in th e determ ination of the size of a lesion or collection in soft tissues or bon e. Magn etic resonance im aging (MRI) is useful for detecting m arrow changes during the early stages of infection. It h as a sen sitivity th at approach es 100% wh en used for th e detection of osteomyelitis. In th e settin g of osteom yelitis, local edem a and hyperem ia result in in creased sign al on T2-weigh ted im ages an d decreased m arrow sign al on T1-weigh ted im ages. However, th ese fin din gs can be difficult to in terpret after acute traum a, repeated in jury (such as in the patient with periph eral neuropathy), or in the presen ce of stain less steel orth opaedic h ardware. MRI is

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also 97% sen sitive an d 92% specific in th e detection an d diagn osis of septic arth ritis. It is im portan t to rem em ber that som e patients, such as those with a pacem aker or a recen tly placed in ferior ven a cava filter or an eurysm clip, are un able to un dergo MRI. Ultrasound is less com m on ly used in th e evaluation of an orth opaedic in fection . However, an ultrasoun d study can be perform ed relatively quickly, is inexpensive, provides real-tim e in form ation , an d does n ot subject th e patien t to radiation . Ultrasoun d can be very useful in detectin g fluid collection s or bon e surface ch an ges, such as in th e presen ce of an abscess or periostitis. O th er im agin g m odalities are also useful in th e workup of m usculoskeletal in fection s. Bon e scin tigraphy with tech netium Tc-99m ph osphate allows for identification of an atom ic areas of in creased perfusion an d osteoblast activity. In th e typical th ree-ph ase bon e scan , th e in itial ph ase dem on strates perfusion of th e radion uclide in to th e tissues, with increased blood flow and tracer distribution in region s of in fection s. Th e secon d, or in term ediate, ph ase is recorded approxim ately 15 m in utes after radion uclide in jection an d dem on strates th e presen ce of tracer in th e extracellular space. Th e fin al ph ase, th e th ird or delayed ph ase, is recorded between 2 an d 4 h ours after in itial in jection an d correlates with osteoblastic uptake of th e radion uclide. Uptake in a specific region during the second phase that is then absent during the third phase is typically consisten t with superficial cellulitis an d n ot osteomyelitis. Leukocyte scans with indium -111 –labelled leukocytes are useful in distin guish in g in fectious from n on in fectious etiologies. Th e two tech n ologies, leukocyte scan s an d bon e scan s, can be used in com bin ation to in crease th e sen sitivity an d specificity wh en evaluatin g for in fection . A m uch n ewer tech nique, positron em ission tom ography (PET) with F-18 fluorodeoxyglucose, h as becom e favorable in th e evaluation of ch ron ic m usculoskeletal in fection due to 100% sen sitivity an d 88% specificity.

LABORATORY STUDIES Laboratory studies are also useful in the evaluation and m an agem en t of m usculoskeletal in fection . Elevation of th e periph eral wh ite blood cell (WBC) coun t with a predom in an ce of polym orph on uclear leukocytes is suggestive of in fection . However, in greater th an h alf of patien ts with m usculoskeletal in fection , an elevated WBC coun t is n ot observed. Th erefore, th e eryth rocyte sedim en tation rate (ESR) an d C-reactive protein (CRP) are th e m ore com m on ly used m arkers of in fection an d in flam m ation . Both ESR and CRP are m arkers of acute inflam m ation. CRP begin s to rise with in 6 h ours of on set of in fection an d return s toward n orm al approxim ately 1 week after in itiation of successful treatm en t. In con trast, th e ESR becom es elevated durin g the first 2 days of infection but does not norm alize un til rough ly 3 weeks after eradication of in fection .

As a result, th e CRP is m ore com m on ly used for diagn osis of acute in fection an d for m onitoring the response to treatm ent. It is important to rem em ber that surgical in tervention also results in elevation of both the ESR and the CRP. Tissue an d fluid specim en s from th e site of in fection sh ould be evaluated by culture and gram stain. Overall, gram stain results in iden tification of a specific organ ism in only one-third of cases. However, gram stain can be extrem ely specific and is often used to guide in itial an tibiotic selection . Th e gold stan dard in diagn osis of in fection is tissue culture. Unfortunately, inadequate sampling, errors in h an dlin g an d processin g, an d effects of previously adm inistered antibiotics can all result in incomplete and false-n egative culture results. Molecular gen etics m ay be th e future diagn ostic tech n ique of ch oice. Th e use of polym erase ch ain reaction (PCR) to detect bacterial DNA with out the n eed for in vitro culture could allow for earlier diagnosis and decrease th e false-n egative rate from previous an tibiotic adm in istration. However, con cern s regarding false-positive results stem m in g from th e extrem e sen sitivity of th is technique rem ain un resolved.

ADULT INFECTIONS Osteomyelitis In strict defin ition , osteomyelitis refers to in flam m ation of bon e or bon e m arrow. Sin ce th is in flam m ation is always the result of infection , th e term “osteomyelitis” implies infection of bone or its m arrow contents. In the adult population , osteomyelitis m ost com m on ly results from con tiguous spread from local infection, traum a, or after a surgical procedure such as open reduction and in ternal fixation . Hem atogen ous spread is far less com m on , but it does occur an d is m ost frequen tly en coun tered in in traven ous drug users. Infection with any bacteria can cause osteomyelitis; h owever, Staphylococcus aureus is the m ost com m on path ogen .

Classification Osteomyelitis can be classified on the basis of patient age (pediatric or adult), causative organism , pathogen esis (contiguous spread, traum atic, hem atogenous), anatom ic location , or duration of symptom s (acute, subacute, ch ronic). These variables can be used individually or in com bin ation for categorization. There are also a num ber of n am ed classification system s th at focus on various clin ical aspects of osteomyelitis, but no one system is un iversally accepted. Th e m ost com m only used classification system for adult osteomyelitis is th e Cierny–Mader staging system , which is based on the an atom ic location of infection within the bone an d the physiologic status of the host (Table 5.2).


TABLE 5.2

CIERNY–MADER STAGING SYSTEM OF ADULT OSTEOMYELITIS Anatomic type Stage 1: Medullary osteomyelitis Stage 2: Superficial osteomyelitis Stage 3: Localized osteomyelitis Stage 4: Diffuse osteomyelitis Physiologic class A host: Healthy B host: Bs: Systemic compromise Bl: Local compromise Bls: Local and systemic compromise C host: Treatment worse than the disease Factors affecting immune surveillance, metabolism, and local vascularity Systemic factors (Bs): Malnutrition, renal or hepatic failure, diabetes mellitus, chronic hypoxia, immune disease, extremes of age, immunosuppression or immune deficiency Local factors (Bl): Chronic lymphedema, venous stasis, major vessel compromise, arteritis, extensive scarring, radiation fibrosis, small-vessel disease, neuropathy, tobacco abuse Reprinted with permission from Cierny G, Mader JT, Pennick H. A clinical staging system of adult osteomyelitis. Contemp Orthop. 1985;10:17–37.

Presentation Th e clin ical presen tation of osteomyelitis is extrem ely variable. Host status, chronicity of infection, anatom ic location, and the offen ding pathogen(s) all factor in to the clinical picture of each individual case. In general, system ic symptom s can in clude fever, ch ills, n igh t sweats, an d m alaise. However, the absence of any or all of these symptom s does not preclude a diagnosis of osteomyelitis. Amyriad of local symptom s m ay also exist. Pain, erythem a, warm th, and swelling are th e m ost com m on local indicators of osteomyelitis. A drain in g sin us tract m ay serve as the cause of, or result from , an underlying bone infection. Wh en th e lower extrem ity is in volved, a limp, pain with weigh t-bearin g, or an in ability to bear weigh t m ay also be associated with osteomyelitis. History and Physical Examination A thorough history should focus on the location, severity, an d chronicity of local and system ic symptom s. A history of previous m usculoskeletal surgery, open fracture, or in fection (in cluding a history of osteomyelitis) m ust always be in vestigated. Curren t an d previous m edication s in cluding antibiotics, as well as drug allergies, should be obtained. Vital signs should always be part of every physical exam in ation, as fever, tachycardia, and hypotension can all indicate system ic illn ess or, in th e worst case, septic sh ock related to hem atogenous spread of in fection. A detailed physical exam in ation should focus on local symptom s by evaluating

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for erythem a, warm th , swelling, and tenderness to palpation . Evaluation of th e skin an d soft tissues m ust in clude careful inspection for localized fluctuance and draining sin uses. In th e setting of prior fracture, bon e stability an d ten dern ess at th e fracture site are assessed in order to determ in e clin ical fracture un ion . With con firm ed or suspected osteom yelitis adjacen t to a join t, th e presen ce of an effusion or pain with range of m otion m ay indicate spread of in fection in to th e join t resultin g in septic arth ritis.

Diagnostic Studies As previously m en tion ed, both im agin g an d laboratory studies are used in com bination to m ake the diagnosis of osteomyelitis. However, th e on ly way to m ake a defin itive diagnosis is with tissue culture. This can be ach ieved th rough surgical biopsy or n eedle aspiration in som e cases. However, the com bin ation of h istory an d physical exam in ation, im aging, an d basic laboratory studies are often sufficient to raise suspicion for th e diagnosis of osteomyelitis and initiate empiric antibiotic therapy. Differential Diagnosis Th e clin ical presen tation of osteomyelitis can be very sim ilar to the presentation of tum ors or fractures. Therefore, th ese diagn oses m ust always be con sidered wh en suspicion for in fection is raised. On ce th e diagn osis of osteomyelitis h as been m ade, th e differen tial diagn osis of causative path ogen s is exten sive. Overall, Staphylococcus aureus is the m ost com m on causative organism . In the setting of ch ron ic osteomyelitis, Staphylococcus epidermiditis, Pseudomonas aeruginosa, Serratia marcescens, an d Escherichia coli are also com m on causative organism s. Microbacteria, fungi, and less virulent path ogens m ust be considered in th e im m un ocomprom ised h ost. Treatment Successful treatm en t of osteomyelitis involves an aggressive, m ultifaceted approach . In cases of acute hem atogen ous osteom yelitis (AHO), an tibiotic th erapy alone can be successful, with surgical debridem en t reserved for refractory scenarios. However, cases of chronic an d nonh em atogen ous osteomyelitis typically require soft-tissue and bony debridem ent in conjunction with system ic and local antibiotic therapy for successful results. Wh en lim b salvage is th e goal of treatm ent, wound m anagem en t as well as treatm en t of fracture n on un ion s, bony defects, an d skeletal in stability m ust follow initial surgical debridem ent and in itiation of an tibiotic therapy. Successful treatm ent of osteomyelitis can be prolon ged an d associated with sign ificant m orbidity. Th erefore, amputation should rem ain a treatm en t option in the m ost complex an d lim bth reaten in g situation s. Adequate surgical debridem ent of nonviable bone and soft tissue is param oun t in successful treatm ent of osteomyelitis. Debridem en t m ust proceed un til viable, bleeding tissue is confirm ed at th e surgical m argin s. In the

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Figure 5.1 Antibiotic beads placed in a trough

of bone following removal of a plate for infection. Here the beads provide no structural support but help in local delivery of antibiotic. (Reprinted with permission from Bucholz RW, Heckman JD, CourtBrown C, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia: Lippincott Williams & Wilkins, 2006.)

presen ce of n on h ost m aterials such as orth opaedic im plan ts, rem oval of all foreign m aterials is typically n ecessary for cure. This is due to the rapid form ation of biofilm s by the infectin g bacteria. Biofilm s are resistant to host defen ses an d an tibiotic pen etration an d, th erefore, typically require h ardware rem oval for effective treatm en t. However, in the setting of a healing fracture, the decision to retain or rem ove h ardware can be difficult. In th e acute settin g, prior to the diagnosis of a non union, rigid internal fixation m ay be retain ed in order to m ain tain fracture stability. If th e fracture goes on to un ion but in fection persists, th e im plan t sh ould be rem oved. In th e setting of a n onunited fracture an d loose h ardware, all loose implan ts sh ould be rem oved. Fracture reduction an d stability sh ould be m ain tain ed by an oth er m eth od such as extern al fixation . Wh eth er h ardware is present or not, adequate and aggressive debridem en t m ust in clude sen din g a sufficien t am oun t of local tissue for path ology evaluation an d laboratory culture with an tibiotic sen sitivity an alysis. Alth ough th orough debridem en t can be devastatin g to lim b fun ction an d stability, in adequate debridem en t is likely to result in treatm en t failure. Early initiation of system ic antibiotic th erapy is also critical to the successful treatm ent of osteomyelitis. Broadspectrum , em piric treatm ent should be started as early as possible, with subsequen t an tibiotic th erapy tailored to a specific organism on the basis of woun d biopsy and culture results. Th e stan dard of care for adult osteom yelitis is 4 to 6 weeks of in traven ous an tibiotics. However, oral therapy can have a role in lim ited situations. On ly antibiotics with good soft-tissue bioavailability such as lin ezolid an d th e fluoroquin olon e an tibiotics are com m on ly used in an oral regim en . Regardless of th e route of an tibiotic adm in istration , th e surgical woun d an d th e ESR an d CRP sh ould be m onitored over tim e to determ ine the success of treatm en t.

In addition to system ic an tibiotic treatm en t, local delivery of an tibiotics h as also been sh own to be very successful. Th e use of an tibiotic-impregn ated polym ethylm eth acrylate (PMMA) cem ent allows for delivery of high concen trations of an tibiotic to local tissues with a reduced risk for system ic side effects and toxicity. Vancomycin, tobramycin, and cefepim e are all com m only used in this m anner as these drugs are available in powder form an d un affected by th e h igh tem peratures gen erated durin g settin g of th e cem en t. PMMA can serve a dual purpose of providin g structural support in th e presen ce of a bone defect as well as allowing for local delivery of antibiotics. Antibiotic-impregnated PMMA can also be fash ion ed in to sm all beads, wh ich can th en be packed in to th e soft tissues, allowin g for local antibiotic delivery without providing structural support (Fig. 5.1). Followin g successful surgical debridem en t an d in itiation of antibiotic therapy, m anagem ent of both surgical an d n on surgical woun ds m ust begin early. Defin itive woun d m an agem en t depen ds on th e status of th e local soft tissues. When possible, prim ary closure or delay prim ary closure of a woun d is preferred. Wh en prim ary closure is n ot possible, eith er local or free m uscle flap coverage sh ould be con sidered. Benefits of m uscle flaps include the reestablish m en t of a physical barrier to in fection from outside sources as well as the elim ination of dead space, wh ich results in in creased local delivery of system ic an tibiotics. Before com m itting to tran sfer of a m uscle flap, th e viability and status of the m uscle to be used m ust be adequately assessed. Transfer of dam aged and nonviable m uscle will on ly in crease th e risk of local in fection , in stead of providin g th e ben efits of a viable m uscle flap. Th e fin al stage of treatm en t for osteomyelitis in volves addressin g bone defects that result from infection and/ or surgical debridem en t. Typically, bone defects are addressed


6 to 8 weeks after th e fin al surgical debridem en t or tissue coverage procedure. At that point in tim e, antibiotic th erapy h as been completed and, in the settin g of a m uscle flap, incorporation of the flap has been achieved. Bone defects can be filled with auto- or allograft. However, autograft rem ain s th e gold stan dard in th e settin g of previous in fection. When a bone defect is greater than 6 cm , treatm ent option s in clude vascularized bon e graftin g an d distraction osteogen esis. With appropriate, stepwise treatm en t, lim b salvage for osteomyelitis can result in successful outcom es. However, the treatm ent can be very lon g, with significan t social, financial, and m edical dem an ds. Therefore, lim b amputation sh ould be considered and discussed in the m ost difficult cases. Wh en con sidered early, amputation m ay offer a less costly treatm ent option, with a m ore rapid return to function.

Septic Arthritis Sim ilar to adult osteom yelitis, septic arth ritis in th e adult population can result from h em atogen ous or adjacen t tissue spread or direct inoculation of th e joint following traum a or surgery. Hem atogenous spread of bacteria is m ost com m on. Im m unocomprom ised h osts, including those with rheum atoid arthritis, system ic lupus erythem atous, or h um an im m un odeficien cy virus, an d th ose takin g ch ronic im m unosuppressive m edication s, are at in creased risk an d susceptibility to join t in fection . In traven ous drug abusers are at an in creased risk as well, due to repeated episodes of bacterem ia. Sin gle join t in volvem en t is m ost com m on, although m ultifocal infection is not rare. Overall, the knee is th e m ost com m on ly affect joint. All healthy joints possess several unique defenses to infection. The synovial fluid in a healthy joint is significantly bactericidal. In addition, synoviocytes have phagocytic potential, allowing for rem oval of bacteria and other path ogen s from th e in tra-articular en viron m en t. Th ese defense m echan ism s are altered in patients with rh eum atoid arthritis an d lupus, resultin g in an increased risk of infection. Previously dam aged joints are also m ore susceptible to in fection , due in part to syn ovial n eovascularity an d in creased syn ovial adhesion factors, both of which increase the chance for hem atogenous bacterial spread an d joint seedin g. Followin g join t in oculation , activation of th e in n ate im m un e response results in local recruitm ent of polym orph on uclear leukocytes. Th e resultan t release of en zym es from the recruited inflam m atory cells, syn oviocytes, and bacteria in itiates degradation of glycosam in oglycan s in th e articular cartilage. Th e end result is destruction of in traarticular cartilage. A large joint effusion can also cause a rise in in tra-articular pressure, resultin g in th e poten tial for reduced blood flow an d aseptic n ecrosis. Th is cascade of even ts begin s early after in fection an d requires urgen t atten tion an d treatm en t in order to avoid join t destruction .

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Classification Th ere is n o specific classification system in place for septic arth ritis. Infections can be grouped on th e basis of route of in oculation , path ogen in volved, an d ch ron icity of in fection. In adult septic arth ritis, the m ost com m on classification is to divide nongonococcal from gonococcal arthritis. In young, sexually active adults, the m ost com m on causative path ogen is Neisseria gonorrhoeae. Oth erwise, S. aureus is th e m ost com m on path ogen . Periprosth etic in fections represent a separate class of septic arthritis and will be discussed later in th e ch apter. Presentation Th e classic clin ical presen tation is on e of a pain ful, eryth em atous join t with a sign ifican t effusion . Patien ts typically h old th e affected join t m otion less. Wh en a join t of th e lower extrem ity is involved, the patient m ay present with th e in ability to bear weigh t on th e in volved lim b. System ic sym ptom s of fever, chills, an d m alaise m ay be presen t. Just as with osteomyelitis, host status, chronicity of infection , anatom ic location, and offending pathogen all factor in to th e clin ical presen tation . History and Physical Examination Th e h istory of presen t illn ess sh ould focus on th e curren t sym ptom s as well as th e patien t’s overall m edical history and any precipitating factors. The patien t should be questioned regarding previous surgeries, traum a to the affected join t, an d any previous join t aspiration s. Pre-existin g join t pain m ust be fully explored. A h istory of gout or pseudogout, rh eum atoid arth ritis, lupus, or any oth er system ic illness m ust be in vestigated as well. A history of outdoor activity or tick bite should also be sought to evaluate for the possibility of Lym e disease (see Ch apter 11). Likewise, any h istory of h um an or anim al bite sh ould be elucidated. A th orough social h istory sh ould in clude th e patien t’s sexual activity, given the h igh prevalence of gonococcal arthritis in th e youn g, sexually active adult. Fin ally, th e patien t’s list of m edications should be reviewed for any im m unosuppressive agen ts th at m ay im pair th e defense against infection or m edications that m ay predispose the patient to gout. Th e m ost com m on fin din gs on physical exam in ation are eryth em a an d warm th associated with a join t effusion an d sign ificant pain with joint m otion. In the im m unocompeten t h ost, m icrom otion pain or pain with even th e sligh test m ovem ent of the joint should be considered septic arthritis un til proven otherwise. However, it is very important to rem em ber that in the elderly or im m un ocomprom ised patien t, th ese sign s an d symptom s m ay be dim in ish ed. Eviden ce of previous surgery or traum a to th e affected join t is im portan t to in vestigate. Ath orough physical exam ination should also evaluate other joints for sim ilar signs of in fection . In n on gon ococcal arth ritis, m on oarticular in volvem en t occurs in 85% to 90% of cases. Polyarticular involvem en t is m ore com m on in cases of gon ococcal, viral, Lym e, an d reactive arth ritis. Polyarticular arth ralgias, fever,

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an d derm atitis are m ost com m on in gon ococcal arth ritis. Septic bursitis, m ost com m on ly olecran on an d prepatellar bursitis, can m im ic septic arth ritis, with diffuse swellin g, eryth em a, an d warm th located about a join t. However, pain with range of m otion is not as dram atic with septic bursitis as it is with septic arth ritis. Fin ally, in dication s of previous gouty arth ritis, such as th e presen ce of soft-tissue toph i, sh ould be sough t, although their presence does not rule out th e diagn osis of septic arth ritis.

Diagnostic Studies Although typically of m inim al use, x-rays are often obtain ed durin g th e evaluation an d workup of septic arth ritis. X-rays m ay reveal th e presen ce of a foreign body followin g a traum atic in jury, or ch on drocalcin osis an d juxta-articular erosion s th at could sign ify ch ron ic or previous gouty arth ritis. In th e settin g of ch ron ic septic arth ritis, x-rays m ay reveal join t space n arrowin g or complete join t space obliteration with arth rofibrosis. However, in acute septic arth ritis, the m ost com m on findings on x-ray are join t effusion and soft-tissue swelling. CT is m ore likely th an x-ray to reveal an effusion ; h owever, CT is oth erwise of m in im al h elp. MRI, on th e oth er hand, is excellent for evaluation of soft-tissue edem a. Th erefore, MRI is the im aging m odality of choice for evaluation of a join t effusion an d surroun din g soft-tissue swellin g. Th is is especially true for evaluation of th e spin e an d sm all join ts of th e h an ds an d feet. Ultrasoun d m ay reveal an effusion wh en a larger joint such as th e elbow, hip, or knee is in volved. Ultrasoun d can be very useful wh en used to guide a n eedle aspiration of a join t. System ic laboratory m arkers of in flam m ation will be elevated in th e settin g of septic arth ritis. ESR an d CRP can n ot be used to m ake a diagn osis of septic arth ritis but are com m on ly used to m on itor clin ical improvem en t followin g treatm en t. An elevated system ic WBC coun t is presen t on ly in 50% of patien ts with septic arth ritis. Sim ilarly, blood cultures are rarely useful, being positive for the causative organ ism in 50% of patien ts with n on gon ococcal arth ritis an d in on ly 10% of th ose with gon ococcal arth ritis. When gon ococcal arth ritis is suspected, a m ucosal surface culture sh ould be perform ed. In th e settin g of acute gon ococcal arth ritis, cervical samples are positive for gon ococcus bacteria in m ore than 90% of wom en and urethral samples are positive in up to 75% of m en . Pharyngeal specim en s are less reliable th an specim en s obtain ed from th e prim ary source of in fection , such as th e ureth ra or cervix. Positive culture from any m ucosal m em brane is m uch less com m on with chron ic and dissem inated gonococcal in fection s. PCR an alysis of cervical, vagin al, ureth ral, an d urin e specim ens allows for screen in g of the asymptom atic patien t an d can be used in con jun ction with tissue culture. The gold standard in the diagnosis of septic arth ritis rem ain s arth rocen tesis with an alysis of th e syn ovial fluid. Join t fluid should be sent for WBC coun t with differential, crystal analysis, gram stain , and culture. Diagnosis of septic

arth ritis is confirm ed when the syn ovial fluid WBC count is greater than 50,000 cells per m m 3 , with a differential of greater th an 75% polym orph on uclear cells. It is critical to rem em ber th at a cell coun t lower than th is does n ot preclude a diagn osis of septic arth ritis, as th e im m un ocom prom ised h ost m ay n ot be capable of m oun tin g such an im m une response. A diagnosis of gout or pseudogout can be m ade wh en crystal an alysis reveals n egatively or positively birefringent crystals, respectively. Gram stain of the syn ovial fluid m ay n ot be diagnostic for a specific organism but can be used to tailor in itial an tibiotic th erapy. Syn ovial fluid culture is m ost important, but positive only in 90% of patien ts with n on gon ococcal arth ritis an d in 25% of patients with gonococcal arthritis. Previous adm inistration of an tibiotics can result in false-negative culture results. PCR tech n iques can also be used to amplify an d detect bacterial DNA presen t in th e syn ovial fluid. However, th ese tests are not curren tly part of stan dard syn ovial fluid an alysis.

Differential Diagnosis Th e differen tial diagn osis of septic arth ritis is broad. As previously m en tion ed, septic bursitis can closely resem ble in tra-articular in fection . However, careful exam in ation , use of appropriate im agin g, an d m in dful aspiration of th e bursa an d n ot th e join t (or vice versa) will con firm th e diagn osis of on e versus th e oth er. Th e clin ical presen tation of crystalline arth ropathy can also be identical to that of septic arth ritis. Join t aspiration with crystal an alysis is typically required to confirm a diagnosis of gout or pseudogout. Reactive arth ritis is an autoim m un e con dition th at closely m im ics septic arthritis. The classic triad of arthritis, especially if it is polyarticular, con jun ctivitis, an d ureth ritis, and a history of previous viral or bacterial infection sh ould raise the suspicion of reactive arthritis. In the case of reactive arth ritis, join t aspiration m ay reveal an elevated WBC coun t, sim ilar to th at seen in septic arth ritis, but gram stain an d culture are n egative. On ce the diagnosis of septic arthritis is m ade, the differen tial diagnosis of causative organ ism s is exten sive. Clin ical h istory an d syn ovial fluid culture are then used to determ ine th e pathogen and dictate defin itive treatm en t. Treatment Surgical treatm en t is th e stan dard of care for n on gon ococcal septic arth ritis. Join t arthrotomy with irrigation an d debridem en t has traditionally been the treatm en t of ch oice. However, arthroscopic irrigation and debridem ent are com m on for larger, easily accessible joints. Regardless of th e m eth od of surgical in terven tion , treatm en t aim s to relieve join t pressure th rough evacuation of effusion , an d rem ove bacteria, in flam m atory m ediators, an d en zym es via copious irrigation. Early treatm en t with this approach can m inim ize cartilage dam age. When in fection in volves intra-articular hardware or allograft m aterial, rem oval of the non host m aterial is often required. In the setting of ch ronic or recurrent infection s, complete synovectomy is


often perform ed. Wh en surgical in terven tion is n ot possible, due to th e patien t’s com orbidities or oth er exten uatin g circum stances, serial joint aspirations can be effective. Serial aspiration s sh ould n ot be con sidered for septic arth ritis of th e h ip or sm all join ts. In addition to surgical decompression an d join t lavage, an tibiotic therapy m ust be started early, typically once joint fluid cultures have been collected. When system ic antibiotics h ave to be started prior to surgical in terven tion , an attempt should be m ade to obtain adequate join t fluid via arth rocentesis before antibiotic adm inistration. Otherwise, culture results m ay be falsely n egative. In th e h ealthy adult, therapy typically begins with a th ird-generation ceph alosporin to treat for both S. aureus an d N. gonorrhoeae. An tibiotic th erapy can th en be adjusted on th e basis of culture results. A m inim um of 4 weeks of antibiotic therapy is standard for n on gonococcal arthritis. Th e treatm en t of acute gon ococcal arth ritis varies significantly from nongonococcal septic arth ritis. Followin g join t aspiration an d con firm ation of gon ococcal in fection, intravenous antibiotic therapy with a third-generation ceph alosporin is in itiated. On ce clin ical im provem en t is noted, typically 24 to 48 hours after antibiotic initiation, antibiotic th erapy is changed to an oral third-generation ceph alosporin . Oral an tibiotics are con tin ued for a m in im um of 1 week or until the resolution of symptom s. Patien ts with large join t effusion s m ay require a lon ger course of an tibiotics un til th e effusion h as resolved, but surgical drainage is rarely required. Patients with ch ronic or dissem in ated gon ococcal in fection s require in traven ous antibiotics for 4 to 6 weeks and should be m onitored closely

A

B

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for evidence of endocarditis and m eningitis. All patients sh ould also be tested for Chlamydia infection and treated as n ecessary, due to a coin fection rate th at approach es 50%.

PEDIATRIC INFECTIONS Osteomyelitis Pathogenesis Un like adult osteomyelitis, osteomyelitis in the pediatric population is m ost com m on ly acute in presen tation an d h em atogen ous in origin . In fection due to traum a, surgery, or spread from a local site is less com m on . Sim ilarly, subacute an d chronic presentations of osteomyelitis are less com m on th an in adults. Pediatric osteom yelitis usually occurs in th e m etaphysis of lon g bon es, especially th e fem ur an d the tibia. In the m etaphyseal region , end-arteries transition into large venous sinusoids and circulation is sign ificantly slowed; this allows blood-borne organism s to m igrate through vessel walls and deposit in th e porous cancellous bon e (Fig. 5.2). In addition , th e m etaphysis h as a relative lack of ph agocytic cells, m akin g it easier for bacteria to establish a clin ical in fection . On ce form ed, purulence can spread th rough th e cancellous bone and eventually rupture through the thin m etaphyseal cortex, creating a subperiosteal abscess (Fig. 5.3). Increasing pressure under th e periosteum can cause isch em ia to th e un derlyin g cortical bon e, wh ich m ay becom e n ecrotic. Th e dead bon e th at results from th is process is kn own as a “sequestrum .” Since the overlying periosteum rem ains viable, n ew bone

C

Figure 5.2 (A) In the metaphysis, a low flow state is present as end arteries transition into venous

lakes; this allows bacteria to migrate through vessel walls. This region is also relatively deficient in phagocytic cells. B: Once established, the infection will eventually track through the porous metaphyseal cortical surface and elevate the surrounding periosteum. If the metaphysis is intra-articular (see section on septic arthritis), the infection can break into the joint and cause a septic arthritis. C: The elevated periosteum lays down new bone initially (involucrum), and the dead bone becomes a sequestrum. (Reproduced with permission from Dormans JP, Drummond DS. Pediatric hematogenous osteomyelitis: new trends in presentation, diagnosis, and treatment J Am Acad Orthop Surg. 1994;2:333–341.)

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A

B Figure 5.3 (A) Sagittal and (B) axial MRI (magnetic resonance imaging) images demonstrating osteomyelitis of the distal tibia with a large posterior subperiosteal abscess. (Courtesy of Wudbhav Sankar, MD.)

can be form ed around th e sequestrum , which is known as the “in volucrum .” A unique aspect of osteomyelitis in the neonate results from the presence of arteries that traverse the physis, allowin g for spread of bacteria an d in fection from th e m etaphysis to th e epiphysis. As a result, adjacen t join t in fection occurs in on e-th ird of all cases of m etaphyseal osteomyelitis in this population. In AHO, m ales are m ore com m on ly affected than fem ales, with th e lower extrem ities in volved m ore frequen tly than the upper extrem ities. Pediatric osteomyelitis is also sligh tly m ore com m on in the warm er m onth s. As in adults, S. aureus is th e m ost com m on pathogen. In the neonatal population , group B streptococci and gram -negative infection s are also com m on . Streptococcus pneumonia an d Streptococcus pyogenes are also com m on in ch ildren youn ger th an 3. In fection from Salmonella species is com m on in ch ildren with sickle cell disease. Im m un ocomprom ised ch ildren are m ore susceptible to fun gal in fection s an d oth er less virulen t path ogen s. Because of an effective vaccin ation program , in fection with Haemophilus influenza type B, once extrem ely com m on, is now rarely encoun tered.

Classification O steom yelitis in ch ildren is gen erally classified by th e ch ron icity of sym ptom s. As m en tion ed, acute osteomyelitis is th e m ost com m on presen tation . Subacute osteomyelitis is caused by a sim ilar m ech an ism but usually in volves a less virulen t path ogen . Patien ts often h ave m ild to m oderate sym ptom s for several weeks or m on th s before th e

diagn osis is m ade. Most respon d to an tibiotics an d surgery is rarely necessary. Chron ic osteomyelitis refers to patients wh o h ave h ad lon g-stan din g in fection s an d h ave developed bon e n ecrosis. Th ese areas are often walled off from th e rest of th e circulatory system by n ew bon e an d gran ulation tissue. As a result, antibiotic penetrance is m arkedly dim inished and m ost require repeated surgical debridem en ts to eradicate th e in fection .

Presentation Ch ildren with acute osteomyelitis classically present with pain , fever, an d refusal to bear weigh t on th e in volved extrem ity. In the n eon atal population, presentation can be m uch m ore subtle, m akin g diagnosis a challenge. The differential diagnosis for pseudoparalysis of a lim b in the n eon ate m ust always in clude osteom yelitis un til infection is defin itively excluded. History and Physical Examination A careful an d detailed h istory m ust be obtain ed from th e ch ild and care provider. Attention should focus on com plain ts of system ic illn ess such as fever, ch ills, or m alaise. A history of recent bacterial or viral infection at any site including th e respiratory and gastrointestinal system s is important to obtain. Likewise, any history of surgery or traum a m ust be noted. A thorough m edical h istory should always be included in any workup, including details of contact with sick in dividuals. In ch ildren old en ough to cooperate, a h istory of acute on set of symptom s with localized bon e pain is m ost com m on . In th ese patien ts, th e pain is


usually severe en ough to lim it activity an d use of th e affected lim b. Physical exam in ation becom es easier with in creasin g age of the ch ild. Th e approach to the child with osteomyelitis m ust be slow and gentle, since significant pain is com m on . Th e m ost com m on finding on physical exam ination is point ten derness to palpation of the osteomyelitic region. Swellin g m ay be localized or in volve th e en tire extrem ity. Eryth em a an d warm th at th e site of in fection m ay sign al spread of th e in fection to the local soft tissues an d poten tial abscess developm ent. If th e affected bone is subcutaneous, redn ess an d warm th at th e skin m ay result from th e osteomyelitis alon e.

Diagnostic Studies Sim ilar to th e workup of adult osteomyelitis, both laboratory an d im agin g studies are routin e in th e evaluation of pediatric osteom yelitis. In th e settin g of AHO , th e m ost com m on finding on plain radiograph s is soft-tissue swellin g. Focal osteopen ia an d periosteal ch an ges in cludin g elevation, th ickening, an d n ew bone form ation can also be observed but are not typically present un til later in the course of disease. It is im portan t to rem em ber th at th ese radiograph ic ch an ges lag beh in d clin ical symptom s by up to 2 weeks, both at clin ical presen tation an d after appropriate treatm ent has been initiated. Lytic lesions are typically not eviden t un til m ore th an 50% of th e bon e m atrix h as been destroyed. CT is n ot com m on ly n ecessary in th e diagn osis of pediatric osteomyelitis. Wh ile ultrasound m ay be helpful to localize an abscess, MRI is th e m ost com m on im aging m odality for the evaluation of osteomyelitis in children. Both th e high sen sitivity and specificity of MRI and the absen ce of exposure to radiation h ave in creased th e use of MRI in th is population . Because of its superior soft-tissue resolution , MRI is extrem ely useful for differentiating cellulitis from osteomyelitis an d for rulin g out th e presen ce of a n eoplasm . In addition to its diagn ostic utility, MRI allows accurate localization of subperiosteal an d soft-tissue abscess, which is extrem ely h elpful in guidin g surgical treatm en t. Although th e use of bon e scan s has been som ewhat replaced by MRI, th is m odality is still useful especially wh en th e site of in fection is un clear. Acute osetomyelitis generally dem onstrates increased uptake on all three ph ases. In certain cases, a “cold’’ scan can be eviden ce of severe and/ or chron ic osteomyelitis. Th e biggest lim itation of bon e scan n in g, h owever, is a relative lack of specificity sin ce a “h ot’’scan can be caused by traum a, tum or, or even disuse. Laboratories studies routinely ordered for evaluation of pediatric osteom yelitis in clude a periph eral WBC coun t with differen tial, ESR, an d CRP. On clin ical presen tation , an elevated CRP will be present in greater than 95% of children with AHO . Elevation of th e ESRabove 40 m m per h our is also com m on. Elevation of the peripheral WBC coun t is m uch less reliable, with an elevated result observed on ly in

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50% of cases. Blood cultures can be helpful but are negative in rough ly h alf th e patien ts. Th e m ost reliable way to obtain a defin itive diagn osis is with bon e aspiration or surgical culture, wh ich reveal th e causative organ ism in up to 85% of cases.

Differential Diagnosis A broad differential m ust be kept in m in d wh en evaluatin g a child with suspected osteomyelitis. While the clinical presentation m ay be clearer in the older child, in the neonate and young child, symptom s are often vague and studies m ay be n ondiagnostic. Fracture and tum or can com m only presen t in a very sim ilar m an n er an d th erefore m ust be excluded durin g th e workup. Septic arth ritis m ust also be excluded. In ch ildren with sickle cell an em ia, bon e in farction m ust be differen tiated from acute osteomyelitis. Treatment An tibiotics sh ould be in itiated early, preferably after bon e aspiration or surgical culture has been perform ed. Initial antibiotic th erapy should be directed at the m ost com m on path ogen for th e ch ild’s age group. Because S. aureus is com m on in every age group, antibiotic therapy should always provide coverage for this organism . Both oral and in travenous antibiotic regim ens have been proven successful, depending on the clinical presentation and the responsible organ ism . The m ost com m on course of antibiotics is 4 to 6 weeks. In patien ts with AHO , prompt in itiation of an tibiotic th erapy m ay preven t th e n eed for surgical in terven tion . Surgical incision and drainage is indicated if an abscess develops or if th e ch ild fails to respond to m edical th erapy alone. With appropriate an tibiotic treatm ent, roughly 50% of patien ts do not require surgery due to the lack of abscess form ation . In cases of late presentation , chronic osteomyelitis, septic arth ritis of th e adjacen t join t, or n on h em atogen ous origin, surgical treatm ent is often necessary.

Septic Arthritis Pathogenesis Septic arthritis in children is often caused by sim ilar path ogen s as for osteom yelitis, but patien ts gen erally presen t m ore rapidly with m ore severe symptom s. Join t infections in the pediatric population are typically due to h em atogen ous spread, alth ough spread from an adjacent infection and direct inoculation from surgery or traum a can occur. As discussed in th e previous section , con tiguous spread from adjacen t m etaphyseal osteomyelitis in n eon ates is possible due to blood vessels th at traverse the physis. In ch ildren , septic arth ritis can be caused by adjacen t m etaphyseal osteom yelitis in th e elbow, sh oulder, h ip, an d ankle sin ce a portion of th e m etaphysis is con tain ed with in th e capsule for th ese join ts. Overall, th e kn ees and hips are the m ost com m only involved joints in all age groups.

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Classification Th ere is n o specific classification system of septic arth ritis in ch ildren . In fection s are typically classified as acute or ch ron ic an d by th e m ech an ism of in fection . Th e age of th e patien t is also useful to con sider. Presentation Clin ical presen tation is very sim ilar to th at of osteomyelitis, alth ough symptom s are often m ore severe. Like oth er in fection s, th e m ost com m on clin ical symptom s on presen tation are fever, pain, an d refusal to m ove th e involved join t. O lder patien ts, in particular, are m ore likely to verbalize th eir pain as associated with m otion of th e in volved join t. Th us, pseudoparalysis is a com m on presen tation , as is th e refusal to bear weigh t wh en a lower extrem ity join t is in volved. History and Physical Examination Th e ch ild an d th e caregiver sh ould be question ed regardin g th e on set of symptom s an d th e presen ce of con stitution al symptom s. Sym ptom s associated with rh eum atic fever an d poststreptococcal arthritis, such as m igratory arth ritis, pain ful subcutan eous n odules, rash an d/ or carditis, sh ould be specifically question ed. A h istory of traum a, in cludin g bite an d pun cture woun ds, sh ould be in vestigated. In addition to th ese specific question s, a th orough m edical an d surgical h istory sh ould always be obtain ed. Physical exam in ation typically reveals a pain ful, eryth em atous, an d swollen join t. Th e h allm ark physical fin din g is severe pain with even m icro-m otion of th e affected join t. When the lower extrem ity is in volved, the in ability to bear weigh t is com m on. In the setting of h ip joint infection, the extrem ity is typically held in a position of sligh t flexion , with m ore pron oun ced abduction an d extern al rotation . Th is position m axim izes th e volum e of th e h ip join t, thereby reducing irritation of the joint capsule that results from th e joint effusion. Diagnostic Studies Diagn ostic studies are th e sam e as th ose discussed for osteomyelitis in th e ch ild. O n ce again , elevation of th e peripheral WBC count is present only in 50% of patients. However, the ESR an d CRP are elevated in m ore than 90% of patien ts with septic arth ritis. Any ch ild suspected of h avin g a septic join t sh ould h ave h is or h er join t aspirated to m ake th e defin itive diagn osis. Syn ovial fluid sh ould be sen t for WBC count, gram stain, culture, and crystal an alysis. Sim ilar to th e adult population , elevation of th e join t fluid WBC count above 50,000 cells per m m 3 is h ighly suggestive of septic arth ritis. Som e ch ildren , h owever, m ay m an ifest lower cell counts. Therefore, an evaluation of the gram stain an d culture are very importan t for determ in in g th e appropriate treatm en t. Plain radiograph s of th e affected join t m ay reveal an effusion with or with out surroun din g soft-tissue swellin g.

Radiograph s sh ould be carefully reviewed to evaluate for th e presen ce of adjacen t osteom yelitis. With a large en ough effusion , join t subluxation or dislocation m ay occur. As with osteomyelitis, MRI is an extrem ely useful tool for evaluatin g septic arth ritis. Alth ough join t aspiration is gen erally sufficient to m ake th e diagnosis, MRI allows visualization of th e adjacen t bon e an d soft tissues an d can th erefore rule out a coexistin g osteomyelitis or soft-tissue abscess. In th e settin g of a suspected septic arth ritis, ultrason ography is m ost useful to guide arth rocen tesis, especially wh en th e h ip is in volved. Bon e scan s are h elpful for m ultiple join t in volvem en t an d can also be used to localize m on oarticular disease when the site of infection is n ot clin ically apparent.

Differential Diagnosis Th e differen tial diagn osis for septic arth ritis in cludes osteomyelitis an d join t effusion caused by in flam m atory arthropathy including rheum atic fever, poststreptococcal arthritis, and juvenile rheum atoid arthritis. Lym e disease is a septic arthritis of sorts but is nonpyogen ic and rarely requires surgical treatm en t (see Ch apter 11). Wh en th e h ip is involved, th e m ost important condition to consider in the differen tial diagn osis for septic arth ritis is tran sien t syn ovitis (see Chapter 11). According to a study by Koch er et al. in 1999, four signs and symptom s can be used to differen tiate th ese two con dition s. Wh en a ch ild presen ts with a fever, in ability to bear weigh t, a periph eral WBC count greater th an 12,000 cells per m m 3 , and an ESR greater th an 40 m m per h our, the diagnosis is septic arthritis m ore than 99% of the tim e. When only three of these signs or symptom s are presen t, th e probability of septic arth ritis drops to 93%. Septic arth ritis is th e correct diagn osis in 40% an d 3% of patients when on ly two or one variable is present, respectively. Treatment Septic arth ritis sh ould be con sidered a surgical em ergen cy, an d irrigation an d drainage in the operating room is th e gold standard of treatm ent. Both open and arthroscopic tech n iques h ave been proven successful, but surgery m ust be accom plish ed urgen tly in order to avoid dam age to th e articular cartilage. Urgent treatm ent is even m ore important for septic arthritis of the hip in order to avoid necrosis of the fem oral head th at can result from the increased intraarticular pressure created by th e join t effusion. Sim ilar to adult septic arthritis, serial aspiration of easily accessible join ts m ay be appropriate in select scen arios. In addition to surgical decompression , early an tibiotic therapy m ust be in itiated. Once synovial fluid has been obtain ed for culture, em piric an tibiotic th erapy sh ould begin . Culture and sensitivity results can then be used to tailor antibiotic th erapy as they becom e available. A m inim um of three weeks of treatm ent is routine, with the poten tial for con version from intravenous to oral antibiotics as clinical improvem ent is observed.


PERIPROSTHETIC INFECTIONS With the num ber of joint arthroplasties perform ed each year exceeding one m illion in the United States alone, the complications of these procedures pose a significant burden on both th e affected in dividual an d th e h ealth care system . One devastating complication of joint replacem en t surgery is periprosthetic infection . The incidence of periprosth etic in fection is rough ly 1% for all form s of arthroplasty. Infection results from direct in oculation or hem atogenous spread of th e offendin g organ ism . Direct inoculation can occur at the tim e of surgery, in the early postoperative period in th e settin g of a drain in g woun d, or at any tim e following join t replacem ent due to traum a to the joint. Hem atogen ous spread can occur at any tim e but is m ost com m on in the two years followin g placem ent of the arthroplasty. It is theorized that the increased infection rate durin g th is period is related to th e relative hypervascularity of th e syn ovium th at results from surgery an d in complete host m echan ical protection of the componen ts.

Classification Periprosthetic infection s are com m only classified on th e basis of th e duration of sym ptom s. Acute in fection s can occur in the im m ediate postoperative period or at any tim e rem ote from arthroplasty due to acute h em atogenous spread. Acute infection s in the postoperative period are defined as those presen ting with in 4 weeks of the in itial surgery. Acute hem atogenous infections are those in which symptom s h ave persisted for less th an 2 to 4 weeks in a previously well-fun ction in g, asym ptom atic join t. Ch ron ic in fection s are those that have persisted for longer than 4 weeks. Th is classification is important in determ ining the appropriate treatm ent. Presentation Th e presen tation of a periprosth etic in fection can be iden tical to septic arth ritis of a native joint. Local symptom s m ay include pain , drain age, and decreased range of m otion. System ic sym ptom s m ay also be presen t, but th eir absen ce does n ot exclude th e diagn osis of in fection . In m any cases, pain is th e on ly sym ptom . In fection m ust also be con sidered as th e cause of failure in any failed arth roplasty. History and Physical Examination Wh en periprosth etic in fection is on th e differen tial diagnosis, history should first focus on the duration of symptom s. Truly acute in fection s m ust be differen tiated from ch ronic and acute-on-chronic processes. Often, th e history is th e on ly way to m ake th is determ in ation . Wh en an acute hem atogen ous infection is suspected, a source of bacterem ia such as a recen t den tal or urologic procedure, infection at a rem ote site, or even penetrating traum a at an oth er site sh ould be sough t. Th e h istory of woun d h ealin g an d appearance is important wh en a chronic infection is

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bein g con sidered. Any h istory of woun d drain age or delayed woun d h ealin g sh ould raise th e suspicion for in fection origin atin g durin g th e origin al perioperative period. Eryth em a, edem a, pain , an d decreased ran ge of m otion are all com m on fin din gs on physical exam in ation . Although wound drainage in the im m ediate postoperative period m ay in crease th e risk of in fection , it is n ot a defin ite sign of in fection. However, wound drainage at any other poin t followin g arth roplasty is h igh ly con cern in g for in fection. Chronically draining woun ds m ust be inspected thorough ly for the presen ce of sin us tracts th at m ay com m un icate directly with th e join t an d prosth esis.

Diagnostic Studies Th e diagn ostic workup for a periprosth etic in fection sh ould always begin with basic laboratory tests including WBC coun t, ESR, an d CRP. In fection can essen tially be ruled out wh en th e ESR, CRP, an d periph eral WBC coun t are all n orm al. However, wh en any on e of these laboratory values is elevated or wh en clin ical suspicion in dicates, join t aspiration should be perform ed. The aspirate m ust be sent for cell coun t an d culture. Un like septic arth ritis in a n ative join t, th e cutoff value for diagn osin g in fection based on th e n um ber of leukocytes in th e join t fluid aspirate is lower. Based on n ewer data, th e cutoff value h as been proposed as low as 1,700 WBCs per m icroliter of joint aspirate. However, 2,500 cells per m icroliter is curren tly th e m ost com m on ly accepted value. In the absence of previously adm inistered antibiotics, positive culture results carry up to 86% sensitivity and 94% specificity for in fection. When antibiotics h ave been adm in istered prior to aspiration , n egative culture results do n ot indicate the absence of in fection. Alth ough join t fluid is often sen t for gram stain an alysis, th e results from such a procedure h ave very low sen sitivity an d specificity as wear debris can be m isin terpreted as bacteria. Wh en preoperative testin g fails to con firm a diagn osis of in fection , intra-operative frozen section analysis of th e periprosth etic tissue an d implan t m em bran es sh ould be perform ed. Alth ough criteria for diagn osin g in fection based on frozen section an alysis h as n ot been defin itively establish ed, m ore th an five n eutroph ils per h igh -powered field is routinely regarded as suggestive of infection. Other serum m arkers and laboratory techn iques have been proposed an d in vestigated recen tly in order to fin d m ore sensitive and specific tests for diagnosing periprosth etic in fection . However, n on e are routin ely used at th is poin t. On e prom isin g serum m arker is in terlukin -6 (IL-6), a factor produced by m on ocytes an d m acroph ages. Alth ough th e serum IL-6 level can be elevated in th e settin g of in fection, inflam m atory arthropathy, or recent surgery, values n orm alize with in 48 h ours of operation an d are not elevated in the presence of aseptic loosening. Molecular biology tech n iques h ave also been in vestigated. PCR h as been used to detect th e presen ce of bacteria, m ost com m on ly by iden tifying th e 16S rRNA gene conserved by nearly all bacterial species. Un fortun ately, use of PCR h as resulted

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A

B Figure 5.4 Radiographs in a patient status post right total hip arthroplasty. At initial follow-up,

radiographs show (A) a well-fixed acetabular component with no evidence of loosening. One year later, radiographs demonstrate (B) lucency around the entire acetabular component. Further workup confirmed the diagnosis of infection.

in a h igh rate of false-positive results an d iden tification of bacteria n ot respon sible for clin ical in fection . Aside from laboratory studies, several im aging m odalities can be used in th e workup an d diagn osis of periprosthetic infection . Although routinely ordered, plain radiograph s of an in fected join t are often n orm al but h elp to exclude a diagn osis of im plan t wear, im plan t failure, or periprosth etic fractures, all of wh ich can m im ic in fection in clin ical presen tation . Periosteal reaction an d osteolysis an d bon e resorption in th e absen ce of implan t wear are two poten tial fin din gs on x-ray th at, wh en presen t, sh ould raise suspicion for infection. Lucency around a previously well-fixed prosthesis m ay indicate in fection but m ust be differentiated from aseptic loosening (Fig. 5.4). Bone scintigraphy can serve as an excellent screening test due to th e high predictive value of a negative result. However, false positives are n ot un com m on an d sign ifican tly reduce th e sen sitivity of this m odality. FDG-PET (fluorodeoxyglucosepositron em ission tom ography) im agin g is a n ewer m odality th at is n ot widely available. Early data regardin g th e use of FDG-PET in th e diagn osis of periprosth etic in fection s sh ow prom ise for th e ability to distinguish aseptic prosthetic loosening from infection.

Differential Diagnosis Although S. aureus is the m ost com m on pathogen in periprosth etic in fection s, th e differen tial diagn osis for poten tial causative organ ism s is quite broad, an d th e possible source and m echan ism of infection is even greater.

Periprosthetic in fection m ust always be considered in the patien t with a persisten tly pain ful or a failed join t prosth esis. Th e presen tation of periprosth etic in fection , aseptic loosening, prosthesis wear, and prosthesis failure can be very sim ilar. Th erefore, each sh ould be con sidered an d workedup wh en any of th e oth ers is con sidered as th e cause of a problem atic prosth esis.

Treatment Because of th e m orbidity of periprosth etic in fection s, every effort sh ould be m ade to preven t th eir occurren ce. Prior to join t replacem en t surgery, patien ts sh ould un dergo routine assessm ent to ensure good dental hygiene and the absen ce of in dolent in fection, such as a urinary tract infection. Antibiotics are always given im m ediately prior to surgery an d durin g th e acute postoperative period. Wounds that con tinue to drain following join t arthroplasty should be m an aged carefully. Followin g join t replacem en t surgery, patien ts m ust be in form ed of th e n eed for sin gle-dose an tibiotic prophylaxis prior to any dental or surgical procedure. Previous recom m en dation s for an tibiotic prophylaxis on ly durin g th e first 2 years followin g join t arth roplasty h ave been chan ged an d n ow in dicate th e n eed for prophylaxis for as long as the prosth esis rem ains in place. Wh en preven tion of in fection fails, successful treatm en t always in volves surgical irrigation and debridem ent of the involved join t and the adm inistration of intravenous an tibiotics for 4 to 6 weeks. Definitive treatm ent depends on th e ch ron icity of th e in fection , h ost respon se to th e


infection, stability of the prosth esis, quality of the local soft tissues, an d th e virulen ce of the causative organism . Treatm en t of acute in fection s typically begin s with irrigation an d debridem en t of th e join t, an d exch an ge of any accessible m odular componen ts, such as the polyethylene liner. Well-fixed components can be m aintained, although implant retention m ay lower th e rate of successful treatm ent due to the presence of an otherwise un detectable biofilm . In traven ous an tibiotic th erapy is in itiated after cultures of the synovial fluid have been obtained. Broad-spectrum antibiotic therapy sh ould be initiated but appropriately narrowed once culture and sensitivity results are available. Persistence of the infection despite appropriate interven tion necessitates further evaluation as to the source of th e infection and treatm en t as if the in fection were ch ron ic. Ch ron ic in fection s are also treated with join t irrigation an d debridem ent. However, when symptom s of infection have been present for m ore than 4 weeks, it is unlikely th at the infection will be eradicated without implant rem oval. In th e Un ited States, two-stage exch an ge arth roplasty is m ost com m on and associated with 90% to 95% success rates. Two-stage exch an ge arth roplasty in volves resection of the implants and placem ent of an antibiotic-impregn ated spacer (Fig. 5.5). Intraven ous antibiotics are th en adm inistered for 6 weeks. Followin g a full course of an tibiotic th erapy, patients are m onitored for an additional 2 to 6 weeks off an tibiotics, to en sure th at sign s an d sym ptom s of in fection do not recur. At that point, if the WBC count, ESR,

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an d CRP are n orm al, an d bon e stock is adequate, a n ew prosth esis can be placed. Alth ough sin gle-stage exch an ge arth roplasty is associated with lower rates of eradication of in fection (70% to 85%), th is procedure is associated with lower patien t m orbidity an d m ay be con sidered in a very select patien t population . Wh en reimplan tation of a prosth esis is n ot possible, resection arth roplasty or arthrodesis m ay be considered. Circum stances th at m ay preclude reimplantation include m ultiple failed previous exch an ge arth roplasties, th e presen ce of an organ ism resistan t to treatm en t, in adequate bon e stock, com prom ised local soft tissues, and a severely ill or com prom ised patien t. Eith er resection arth roplasty or arth rodesis m ay be con sidered for join ts of th e upper extrem ity wh ile arth rodesis is m ost com m on for th e kn ee, an d resection is typically preferred for th e h ip. In th e patien t too ill to un dergo surgery or a patien t with a lim ited life expectan cy, ch ron ic an tibiotic suppression m ay also be considered. When all other treatm en t option s have failed, amputation of th e in volved extrem ity m ay be th e on ly option for eradication of in fection .

NECROTIZING FASCIITIS Alth ough n ecrotizin g fasciitis is on e of th e least com m on soft-tissue infections, it is associated with significant m orbidity an d m ortality. Prom pt diagn osis an d in itiation of appropriate treatm en t are critical for patien t survival. Wh en

Figure 5.5 (A) Anteroposterior (AP) and (B) lateral radiographs demonstrating an antibiotic spacer in a knee after explantation of an infected knee arthroplasty.

A

B

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surgical intervention is delayed, m ortality as h igh as 75% has been reported.

Classification Gram stain an d culture results can be used to classify n ecrotizin g fasciitis in to on e of th ree groups. Type 1 in fection s are m ost com m on , accoun tin g for 80% to 90% of all cases. In th is type of n ecrotizin g fasciitis, gram stain an d cultures reveal a polym icrobial in fection , in volvin g an aerobic an d non –group A streptococcus bacteria. Wound cultures typically reveal th e presence of four to five bacteria species. Type 1 infection s are associated with abdom inal an d perineal woun ds an d frequen tly affect th e im m un ocom prom ised host. Type 2 infection s are m ost com m on in the extrem ities an d result from th e presen ce of group A β -hem olytic streptococci species. Staphylococcusspecies are th e m ost com m on second species presen t when in fection is not due to group A β -hem olytic streptococci alone. Type 3 infections often result from exposure to seawater or m arin e an im als an d are ch aracterized by th e presen ce of th e gram -n egative rod m arin e vibrios. Presentation Prom pt an d correct diagn osis of n ecrotizin g fasciitis can be m ade extrem ely difficult because of its often ben ign in itial presen tation . Th e m ost com m on presen tation is quite sim ilar to th at of cellulitis with a localized region of in flam m ation , swellin g, an d eryth em a. Necrotizin g fasciitis is often differen tiated from cellulitis by a disproportion ate level of pain an d rapid progression of sign s an d sym ptom s. Com m on ly, region s of skin in duration an d eryth em a expan d rapidly, at a rate of greater than 1 cm per hour, despite the adm in istration of in traven ous an tibiotics. Classic sign s of necrotizing fasciitis appear later and con sist of blister and bullae form ation , skin discoloration an d slough in g, an d crepitus due to the presence of gas in the soft tissues. Bullae an d blisters m ay in itially drain serosan guin eous fluid but later becom e h em orrh agic. As th e fascia an d overlyin g superficial fat n ecrose, th e classic “dish water pus’’ an d foul-sm elling drainage becom e obvious. In addition, the in ten se pain observed early in th e course of th e disease m ay give way to localized an esth esia, as cutan eous n erve en din gs are destroyed. Fever an d ch ills m ay presen t early, but symptom s of system ic sh ock, in cludin g hypoten sion , tachycardia, an d altered m en tal status, are com m on later. Ren al an d h epatic failure, coagulopathy, an d acute respiratory distress syn drom e can all en sue. History and Physical Examination A proper history and physical exam ination will result in h eigh ten ed clin ical suspicion for n ecrotizin g fasciitis, which is critical for early in itiation of treatm en t. Alth ough necrotizing fasciitis m ost com m only results from an in jury to th e affected site, th e patien t m ay n ot recall such an in jury. Any lesion that allows bacteria to breach the skin can result in n ecrotizin g fasciitis. Blun t an d pen etratin g traum a, sur-

gical in cisions, burns, insect bites, and ulcers h ave all been implicated as the cause of infection, but in up to 45% of infections, the portal of bacteria entry is not evident. Physical exam ination findings are quite varied and related to th e m any poten tial sign s an d sym ptom s described in th e previous section . In fection typically begin s in th e extrem ities but can rapidly spread to the trunk. Involvem ent of the trunk and perineal region is associated with significantly h igher m orbidity an d m ortality.

Diagnostic Studies Basic laboratory studies sh ould in clude a com plete blood cell coun t, comprehensive m etabolic panel, and coagulation studies. Anem ia, throm bocytopenia, hyponatrem ia, hypocalcem ia, azotem ia, hypoproteinem ia, hypoalbum in em ia, an d hyperbilirubin em ia are all com m on . ESR, CRP, an d creatin in e kin ase values are typically elevated. Laboratory values m ay be norm al in early infection but becom e progressively m ore abnorm al as th e disease progresses. Several m odels h ave been developed to h elp diagnose n ecrotizing fasciitis an d distin guish it from oth er soft-tissue in fection s. In on e sim ple m odel developed by Wall et al., sim ultaneous hyponatrem ia, with a serum sodium level of less than 135 m m ol per liter, and leukocytosis, with elevation of the WBC count to greater than 15,400 cells per m icroliter, is 90% sensitive for n ecrotizing fasciitis. However, th is m odel sh ould on ly be used to rule out th e diagn osis of n ecrotizin g fasciitis as both th e specificity and th e positive predictive value are low, at 76% and 26%, respectively. Th e Laboratory Risk In dicator for Necrotizin g Fasciitis (LRINEC) is another com m only used m odel that com bines the results of six com m on laboratory studies (CRP, WBC count, hem oglobin, sodium , creatinine, an d glucose) to predict the probability of n ecrotizing fasciitis. Th e positive predictive value of th is m odel is 92% wh en used to detect early cases of disease. In addition to laboratory studies, radiograph ic evaluation is critical in m akin g a tim ely diagnosis. Plain film s are m ost often norm al, even in th e presen ce of disease, but are h elpful for detectin g gas in th e soft tissues wh en present. CT is very useful in the evaluation of a suspected patient. Com m on findings in the presen ce of disease include gas in the soft tissues, fascial thickening, an d stranding and attenuation of the subcutan eous fat. However, a negative CT does not rule out the diagnosis. A CT scan can also be extrem ely h elpful in delin eatin g th e exten t an d m argin s of soft-tissue in volvem en t. Th e sensitivity of MRI is greater than 90%; however, MRI is of a lesser priority in the evaluation of patien t due to th e am oun t of tim e required to obtain a m ean in gful study. Differential Diagnosis Necrotizin g fasciitis is m ost com m on ly m isdiagn osed as cellulitis. As previously m ention ed, early stages of necrotizin g fasciitis m ay be nearly identical to cellulitis, so adequate clin ical suspicion sh ould result in furth er workup


to defin itively con firm or exclude th e m ore serious con dition. Other diseases that m ay be confused with necrotizing fasciitis in clude erysipelas, lymph an gitis, gas gan gren e, an d acute febrile neutrophilic derm atosis.

Treatment Successful treatm en t relies on prompt diagn osis with subsequen t surgical debridem ent and in itiation of broadspectrum antibiotic therapy. Surgical in terven tion sh ould be appropriately aggressive, with rem oval of all in volved skin, fascia, and m uscle during th e initial debridem en t. Th e resultin g woun d m ust be evaluated on a daily basis for furth er progression of the infection and tissue necrosis. Repeat debridem en t is often necessary until a stable, viable woun d is achieved. Between debridem ents, the wound sh ould be covered with sterile dressin gs to prom ote h ealing and decrease the risk of secondary infection. In som e circum stances, lim b amputation is required initially in order to preserve th e patien t’s life. Followin g appropriate surgical debridem en t, the resulting wound(s) and soft-tissue defect(s) m ay require skin graftin g or free tissue tran sfer for definitive coverage and closure. It is important to rem em ber that surgical in tervention is the only treatm ent for necrotizing fasciitis proven to reduce m ortality. Antibiotic therapy m ust be initiated as soon as necrotizin g fasciitis is suspected and m icrobial cultures are obtain ed. In itial em piric th erapy sh ould in clude coverage for gram -positive, gram -negative, and anaerobic organism s. Broad-spectrum empiric coverage typically includes clindamycin in com bination with im ipenem , m eropenem , ampicillin/ sulbactam , or piperacillin/ tazobactam . The antibiotic regim en can be tailored to culture and sen sitivity results on ce available. Alth ough an tibiotic th erapy is critical to successful treatm ent, it can never be used as the sole interven tion . Antibiotics can help reduce the system ic effects of th e infection and decrease bacterial load but cannot eradicate th e in fection alon e. Th is is due to lim ited an tibiotic delivery to th e site of in fection , wh ich results from poor vascularity of the fascia that is further comprom ised by the infection itself.

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In addition to surgical debridem en t an d an tibiotic adm in istration n ecessary for successful treatm en t, supportive care with appropriate fluid resuscitation an d blood pressure m ain ten an ce are often needed in the septic patien t. Nutrition al support is critical in all patien ts due to th e loss of fluid, electrolytes, an d protein th rough th e often large surgical woun d(s). Adjunctive therapy with intravenous im m un oglobulin G, recom bin an t h um an -activated protein C, an d hyperbaric oxygen h ave all been reported to improve outcom es but h ave yet to becom e stan dard in treatm en t protocols.

SUMMARY Musculoskeletal infection s affect patients of all ages, can involve any anatom ic region in the body, and result from any on e of an in fin ite n um ber of etiologies. Successful treatm ent relies on proper and tim ely diagnosis followed by antibiotic therapy, surgical intervention , or both. Careful attention m ust be given to infections in the settin g of fractures and the presen ce of orth opaedic h ardware. Given the m orbidity of m usculoskeletal infections and the treatm ent required for successful eradication , future research m ust focus on prom pt an d accurate diagn osis as well as preven tion .

RECOMMENDED READINGS Bauer TW, Parvizi J, Kobayashi N, Krebs V. Current con cepts review: diagnosis of periprosth etic infection. J Bone Joint Surg Am. 2006;88:869 –882. Bellapian ta JM, Ljun gquist K, Tobin E, Uh l R. Necrotizing fasciitis. J Am Acad Orthop Surg. 2009;17:174 –182. Cierny G III, DiPasquale D. Treatm ent of chronic infection. J Am Acad Orthop Surg. 2006;14:S105 –S110. Dorm ans JP, Drum m ond DS. Pediatric hem atogen ous osteomyelitis: n ew tren ds in presen tation , diagnosis, and treatm ent. J Am Acad Orthop Surg. 1994;2:333 –341. Mader JT, Wang J, Calhoun JH. Antibiotic therapy for m usculoskeletal infection. J Bone Joint Surg Am. 2001;83:1878 –1890. Patel A, Calfee RP, Plan te M, et al. Meth icillin -resistan t Staphylococcus aureus in orthopaedic surgery. J Bone Joint Surg Br. 2008;90:1402 – 1406.

6

Metabolic Bone Diseases Aasis Un n an u n t an a Ben jam in McArthu r

Brian P. Gladn ick Moira McCarthy Joseph M. Lan e

INTRODUCTION Metabolic bone disease encompasses a group of disorders that impair balances between bone form ation and bon e resorption or defects in m in eralization of bon e. Th eoretically, any disease affectin g bon e cells, collagen, noncollagenous protein, or m ineral deposition could adversely affect bone and, therefore, con stitute disease in volving bon e m etabolism . Th e m ost com m on an d perh aps m ost important m etabolic bone disease is osteoporosis. Other significant m etabolic bon e diseases in clude rickets an d osteom alacia, ren al osteodystrophy, an d Paget’s disease of bon e. Th is ch apter will provide basic kn owledge of factors that lead to the developm ent of m etabolic bone disease, along with an overview of m etabolic bone disorders that are com m only encountered during clinical practice.

MINERAL HOMEOSTASIS AND ENDOCRINE FUNCTION IN BONE Calcium is the m ost abundant m ineral in hum an body. Calcium accretion begins during the third trim ester of fetal life, in creases th rough out ch ildh ood, adolescen ce, an d adulthood before peaking in early adulthood an d declin ing thereafter. The rate of decline is approxim ately 1% to 2% per year. Th e total body calcium is exch an ged in th e rem odeling process m ediated by osteoblasts and osteoclasts. Nin ety-n in e percen t of th e total body calcium is stored in skeleton , leaving approxim ately 1% to circulate in th e extracellular fluid. It is th is 1% that controls and regulates the body fun ction . Th e extracellular con cen tration of calcium

is gen erally 10 5 -fold greater than intracellular concentration of calcium . Forty percen t of th e circulatin g calcium is boun d to album in , 45% is in th e active, free, ion ized form , an d 15% is bound to ph osph ate an d oth er in organ ic ion s. Abn orm alities in the serum protein concen trations alter the am oun t of calcium in th e extracellular fluid. Th erefore, it is importan t to calculate th e corrected serum calcium level wh en th e circulatin g album in is abnorm al in order to get an accurate estim ate of th e free calcium , or on e can directly m easure th e actual free, ion ized calcium . Calcium in the skeleton exists as a hydroxyapatite crystal in th e m in eral ph ase of bon e. Th e crystal con tributes to th e m ech an ical properties of bon e an d also serves as a calcium and phosphate reservoir that can be rapidly m obilized to support n um erous biological system s if n eeded. Th e biological action s of calcium are attributed to the ion ized fraction , wh ich is readily exch an geable with pools of calcium in bone, blood, and intracellular sites. Calcium regulates a n um ber of essen tial cell fun ction s such as in tracellular sign alin g an d n eurom uscular activity in cludin g m uscle con traction . Calcium is prim arily absorbed in the duodenum and proxim al jejun um an d is controlled principally by 1,25dihydroxy-vitam in D. Gastric acid is n ecessary for th e absorption of calcium . Despite calcium intake of 400 to 1500 m g per day, the n et calcium absorption from the intestin e is between 200 an d 400 m g per day. Th e system s of absorption an d excretion are tigh tly coupled an d regulated by the ionized serum calcium concentration . The kidneys filter between 8 to 10 g of calcium per day, of wh ich on ly 2% to 3% is excreted. Most of th e filtered calcium is reabsorbed through passive m echanism s in the proxim al tubules with

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the rem ainder being reabsorbed in the loop of Henle and the distal convoluted tubules. These processes are h igh ly regulated, an d certain drugs th at affect ren al tubule physiology m ay alter calcium h om eostasis. For example, th iazide diuretics reduce th e excretion of urin e calcium , an d thus increase its serum con centration. Alternatively, loop diuretics en h an ce th e excretion of calcium an d th erefore decrease th e level of serum calcium . Sim ilar to calcium , 85% of th e 600 g of ph osph orus in th e body is stored in bon e. Ph osph orus is importan t for structural proteins, enzym es, transcription factors, high en ergy stores such as ATP, an d n ucleic acids. Daily ph osph ate an ion loads are between 500 an d 1000 m g. Ph osph ate an ion s are absorbed passively th rough th e sm all in testin e. 1,25-dihydroxy-vitam in D activates active tran sport of ph osph ate, resultin g in absorption of up to 90% of the in testin al ph osph ate. Renal excretion of phosphate is depen den t on th e daily ph osph ate load. Parathyroid h orm on e (PTH) regulates serum ph osph ate con cen tration s by decreasin g its reabsorption from th e proxim al tubule. Calcium –ph osphate hom eostasis is achieved by the coordin ation am on g th ree organ s: in testin e, kidn eys, an d skeleton. Calcium balance becom es positive during skeletal growth in ch ildh ood an d adolescen t, pregn an cy, an d lactation . Con versely, n egative balan ce m ay occur with high rates of bone rem odeling during estrogen deficien cy an d with som e disorders such as hyperthyroidism or prim ary hyperparathyroidism . Th e regulation of calcium – ph osph ate h om eostatic system to m ain tain its balan ce is m ediated prim arily by parathyroid h orm on e (PTH), vitam in D, an d calciton in . On a larger tim e scale, th ese horm ones con trol ion ized calcium or ph osphate levels through changes in intestinal absorption or kidney excretion . However, on th e m ore im m ediate tim e scale th ey act on bon e.

Parathyroid Hormone PTH, produced by th e ch ief cells of parathyroid glan d, plays a m ajor role in calcium hom eostasis. Th e actions of PTH are directly th rough bon e an d kidn eys an d in directly th rough stim ulation of 1-hydroxylation of 25-hydroxy-vitam in D to 1,25-dihydroxy-vitam in D. In bon e, PTH stim ulates th e release of calcium an d ph osph ate. In th e kidn ey, it produces th e reabsorption of calcium an d in h ibits th at of ph osph ate. In addition , PTH in creases th e activity of th e ren al 1α-hydroxylase, thereby enh ancin g the synthesis of 1,25-dihydroxy-vitam in D, which , in turn, in creases the intestin al absorption of calcium an d ph osph ate. As a result of these three actions, serum calcium rises, wh ile serum ph osph ate declin es. Gen erally, th ere are th ree m ain physiological regulators of PTH secretion an d synthesis: extracellular calcium , phosphate ions, and 1,25-dihydroxy-vitam in D. Am ong the three regulators, extracellular calcium con centration is th e m ost im portan t physiological regulator of th e secretion of PTH.

Th e action of PTH on bon e is complex an d partially un derstood. PTH activates its receptor, wh ich is expressed on strom al cells an d osteoblasts. O n ce activated, th e expression of M-CSF an d RANKL is in creased, wh ich subsequen tly en h an ces th e form ation of osteoclasts from th e precursor cells an d in creases th e activity of th e existin g m ature osteoclasts. Therefore, increased secretion of PTH associated with prim ary hyperparathyroidism leads to an increase in osteoclast cell num ber an d activity. Paradoxically, in term itten t PTH adm in istration leads to in creased am ounts of trabecular bone. This anabolic activity of PTH, h owever, is n ot well un derstood. Depen din g on the dose of PTH given , th e m ode of adm in istration (in term itten t or con tin uous), an d th e specific target site (trabecular or cortical bone), th e net effects of PTH on bone can be eith er anabolic or catabolic.

Vitamin D Wh en exposed to sun ligh t, cutan eous ch olesterol (7dehydroch olesterol or provitam in D 3 ) absorbs solar radiation and transform s itself into previtam in D 3 , wh ich rapidly un dergoes an isom erization process to vitam in D 3 . Vitam in D 3 is th en tran slocated from th e skin in to th e circulation , wh ere it is boun d to vitam in D –bindin g protein. Vitam in D is also foun d in food. Th e m ajor n atural sources of vitam in D are oily fish such as salm on an d m ackerel, fish liver oils, an d cod liver oil. Th ere are two types of vitam in D: vitam in D 2 an d vitam in D 3 . Vitam in D 2 derives from yeast an d plan ts, wh ereas vitam in D 3 is foun d in oily fish an d cod liver oil an d also m ade in th e skin . Vitam in D 2 is approxim ately 30% as effective as vitam in D 3 in m ain tain in g vitam in D status. Once vitam in D enters the circulation , it is transported an d m etabolized by liver to 25-hydroxy-vitam in D (Fig. 6.1). It is 25-hydroxy-vitam in D th at clin ician s use to determ in e th e status of vitam in D wh eth er deficien cy, sufficien cy, or in toxicated. Because the liver has a large capacity to produce 25-hydroxy-vitam in D, m ore th an 90% of th e liver tissue h as to be in jured before it is un able to m ake an adequate quan tity of 25-hydroxy-vitam in D, which is transported to the kidneys where the enzym e 1αhydroxylase m etabolizes 25-hydroxy-vitam in D to 1,25dihydroxy-vitam in D, wh ich is an active form of vitam in D. This hydroxylation step is activated by PTH but repressed by calcium as well as by the active form of vitam in D itself. In addition , th e active form of vitam in D activates the 24-hydroxylase en zym e in the kidney, which creates 24,25dihydroxy-vitam in D, an in active form of vitam in D. Th e m ajor fun ction of 1,25-dihydroxy-vitam in D for bon e m in eralization process is to m ain tain blood levels of calcium an d ph osph orus in th e n orm al ran ge for proper m in eralization . 1,25-dihydroxy-vitam in D, h owever, does not h ave a direct effect in th e m in eralization process. There are several addition al roles of th is active vitam in D in cludin g in creased bon e-specific alkalin e ph osph atase,

Chapter 6: Metabolic Bone Diseases

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regulated by serum calcium . Wh en serum calcium rises acutely, th ere is an in crease in secretion of calciton in . Con versely, an acute declin e in serum calcium leads to a correspon din g decrease in serum calciton in level. If hypercalcem ia is severe or prolonged, the C cells, however, exhaust their secretory reserve. Because of its properties, there are application s to use calciton in for various disorders th at are ch aracterized by in creased bon e resorption such as Paget’s disease, osteoporosis, and hypercalcem ia of the m align an cy. In addition , calciton in h as been used as a tum or m arker for m edullary thyroid carcin om a (MEN type II).

BONE STRENGTH, BONE MINERAL DENSITY, AND BONE QUALITY

Figure 6.1 Vitamin D metabolism. After undergoing photocon-

version in the skin, Vitamin D is metabolized first in the liver and then in the kidney. The target end organs of the active vitamin D, 1,25-dihydroxy-vitamin D, are the intestine and bone. (Adapted from Brinker MR, O’Connor DP. Basic Sciences: Bone. In: Miller MD, ed. Review of Orthopaedics, 5th ed. Philadelphia, PA: Saunders, an imprint of Elsevier, 2008:20.)

osteocalcin , an d osteon ectin an d altered proliferation an d apoptosis of skeletal cells. Non skeletal roles for vitam in D involve can cer prevention, facilitated m uscle function, and en h an cem en t of th e im m un e system . Vitam in D deficiency can be caused by a variety of conditions and disorders such as excessive sunscreen use, cloth ing of all sun-exposed areas, obesity, aging, and som e m edication s. Asunscreen with a sun protection factor (SPF) of 8 reduced vitam in D production by 95%. It is, th erefore, recom m en ded to con sider exposin g body parts (h an ds, face, an d arm s) to a suberythem al degree of sunlight (an am oun t that would cause m ild pinkness to the skin) 2 to 3 tim es a week before applyin g sun screen lotion . In creased vitam in D deposition in body fat is th e cause of vitam in D deficien cy in obesity. Som e m edication s such as anticonvulsants, glucocorticoids, and rifampicin enhance th e catabolism of 25-hydroxy-vitam in D an d th us cause vitam in D in sufficiency.

Calcitonin Calcitonin is a peptide that is secreted by thyroid C cells. It con sists of 32 am in o acids an d acts again st osteoclasts in their resorptive function. Calcitonin is m etabolized by m any organ system s, in cluding the kidney, liver, bone, an d even the thyroid gland. The secretion of calcitonin is

Bon e stren gth reflects th e in tegration of two m ain factors: bon e den sity an d bon e quality. Bon e m in eral den sity (BMD) h as been shown to correlate well with bone strength as a whole; however, there are still som e lim itations. For instance, it does n ot distinguish the specific attributes of th e th ree dim en sion s of bon e quality such as th e size an d sh ape of th e bon e, th e cortical and trabecular components, and the m icroarch itecture or intrinsic property of the bon e m atrix. In addition, it represents on ly a static param eter, wh ich provides n o in form ation regardin g bon e turn over in an individual patien t. Curren tly, th ere has been an increasin g in terest in an oth er determ in an t of bon e stren gth : bon e quality. Bon e quality is a fun ction of th e structural and m aterial properties of bone. The structural properties include its geom etry and m icroarchitecture, whereas the m aterial properties include its m ineral and collagen com pon en ts. In gen eral, bon e un dergoes con tin uous ren ewal by the process of coupled bone resorption and form ation, so-called “bon e rem odelling.’’ This process, therefore, influences both BMD an d bon e quality an d con sequently affects th e whole bon e strength (Fig. 6.2).

Bone Turnover or Bone Remodelling Bon e turn over is th e principal factor th at con trols both th e quality an d th e quan tity of bon e. An im balan ce between bon e resorption an d bon e form ation ultim ately results in a net loss or gain of the bon e tissue. High bone turnover leads to thinnin g of the bone structure, resultin g in abnorm al bone m icroarchitecture and reduced bone m ineralization. Conversely, low bone turn over results in hyperm ineralization and accum ulation of m icrodam age, which leads to increased bone fragility. Bon e turn over can be assessed by com bin ed calcium balance and isokinetic studies, which are tim e consum ing an d expen sive; by tetracyclin e-based h istom orph om etry, wh ich is an in vasive tech nique; or by biochem ical bone m arkers. Th e m easurem en t of bioch em ical bon e m arkers h as several advantages including that it is generally available, can be assessed serially, and can m easure changes in bone turnover over a sh ort tim e in terval. Th us, th e m easurem en t of

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Figure 6.2 Bone strength is a function of bone

mineral density (BMD) and bone quality. The bone turnover rate affects both BMD and bone quality and subsequently contributes to overall bone strength.

bioch em ical bon e m arkers represen ts a sign ifican t advan ce in th e evaluation an d treatm en t of patien ts with m etabolic bon e diseases. Abiochem ical bone m arker can be categorized as a bone form ation m arker or a bon e resorption m arker. Each of the m arkers represen ts a product that is released during either bone form ation or bon e resorption (Table 6.1). Durin g bon e form ation , osteoblasts produce type I collagen , which is their m ajor syn th etic product. Carboxyterm inal propeptide an d am in oterm in al propeptide of type I col-

TABLE 6.1

BIOCHEMICAL MARKERS OF BONE TURNOVER Bone Formation Markers

Bone Resorption Markers

Serum ■ Bone-specific alkaline phosphatase ■ Osteocalcin ■ Carboxyterminal propeptide of type I collagen (PICP) ■ Aminoterminal propeptide of type I collagen (PINP)

Serum ■ Tartrate-resistant acid phosphatase ■ N-telopeptide of collagen cross-links (NTx) ■ C-telopeptide of collagen cross-links (CTx) Urine ■ Free and total pyridinolines (Pyd) ■ Free and total deoxypyridinolines (Dpd) ■ N-telopeptide of collagen cross-links (NTx) ■ C-telopeptide of collagen cross-links (CTx)

(Adapted from Camacho P. Biochemical markers of bone turnover. In: Favus MJ, ed. Primer on the Metabolic Bone Diseases and Disorders of Mineral Metabolism. 6th ed. Washington, DC: American Society for Bone and Mineral Research, 2006:127.)

lagen, known as PICP and PINP, respectively, are cleaved from the newly form ed collagen m olecule and, therefore, can be used as th e indices to indicate type I collagen biosynthesis. Osteoblasts also secrete a variety of noncollagenous protein s, two of wh ich are used clin ically as m arkers of osteoblast activity: bon e-specific alkalin e ph osph atase an d osteocalcin . It is th ese n on collagen ous products th at are m ost useful as m arkers for bon e form ation . Although alkaline phosphatase is derived from several tissues, th e two m ost com m on sources are liver and bon e. The utilization of tissue-specific m on oclon al an tibodies allows for th e differentiation between liver and bone isoform ; h owever, the bon e isoform h as 10% to 20% cross-reactivity with th e liver isoform . Durin g osteoclast-m ediated bon e resorption , th e collagen structure with in bon e is degraded. Th is collagen degradation product is used as an in dicator for bon e resorption. In general, collagen m olecules in bone m atrix are staggered to form collagen fibrils by covalent cross-links. Th ese cross-lin ks con sist of pyridin olin es (Pyd) an d deoxypyridin olin es (Dpd). Pyd an d Dpd cross-lin ks occur at two interm olecular sites in collagen m olecule: am inoterm in al-telopeptide an d carboxy-term in al-telopeptide. As part of th is degradation process, cross-lin ked collagen peptides from both th e am in o-term inal-telopeptide (NTx) an d the carboxy-term inal-telopeptide (CTx) are released an d ach ieve m easurable concentration s in both serum and urin e (Fig. 6.3). Th erefore, wh en osteoclasts resorb bon e, they release a variety of collagen breakdown products into the circulation that are furth er m etabolized by liver and kidney. These include free Pyd, free Dpd, NTx, and CTx. In addition to th ese m arkers, serum tartrate-resistan t acid ph osph atase (TRAP) h as been used to evaluate bon e resorption. TRAP is a lysosom al enzym e th at is present in osteoclasts. It is released in to th e circulation wh en bon e is being resorbed. TRAP, however, is not entirely specific


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Figure 6.3 The collagen molecule is a triple helix consisting of two pro-α 1(I) chains and a single

pro-α 2(I) chain. The collagen triple helix is cross-linked to adjacent molecules at the amino(N)- and carboxy(C)- terminals (as circled in the figure). During osteoclast-mediated resorption of bone, the collagen molecule is degraded, releasing these cross-linked N-telopeptides (NTx) and cross-linked C-telopeptides (CTx). NTx and CTx are specific for bone resorption. (Adapted from Unnanuntana A, Gladnick BP, Donnelly E, Lane JM. The assessment of fracture risk. JBJS Am. 2010; 92:749.)

for the osteoclasts, an d the enzym e is relatively unstable in frozen samples.

tatively th e m ass of hydroxyapatite. Th ese two tech n iques, h owever, are n ot widely used in clin ical practice.

Bone Material Property

Bone Structural Property

Bone is a composite m aterial, consistin g of m inerals, protein s, water, cells, an d oth er m acrom olecules (lipids, sugars, etc). Although bone cells are the principal regulators of bon e m etabolism , bon e m atrix an d m in erals h ave a fun ction in th e control of the cell-m ediated process. Therefore, the inorganic and organ ic compon ents of the bon e h ave both structural an d regulatory properties. Th e degree of m in eralization of bon e tissue, wh ich reflects the m ineral property of bon e, influences n ot only th e m echanical resistance of bon es but also the BMD m easured by dual-energy X-ray absorptiom etry (DEXA). Sim ilar to the m ineral content, collagen and oth er extracellular m atrices are importan t con stituents of the bony composition . Th e n on collagen ous protein s are n ot as abun dan t as collagen , but th ey provide for th e regulation of m in eralization , wh ich reflects bon e stren gth . Th e degree of m in eralization of bon e tissue can be determ in ed by tetracyclin e-labeled transiliac bone biopsy, Fourier tran sform ed infrared spectroscopy (FTIR), and phosph orus-31 solid-state n uclear m agn etic reson ance spectroscopy (31P solid-state NMR). Th e FTIR tech n ique can exam in e th e relative am oun t of m inerals and m atrix con ten t, collagen m aturity, and the arran gem en t of apatite an d organ ic m atrix, wh ereas th e 31P solid-state NMR im agin g can be used to m easure quan ti-

Th e structural properties of bon e can be divided in to m acroarchitecture an d m icroarchitecture. Th e m acroarchitecture, or bon e geom etry, refers to th e size an d sh ape of th e bon e. Microarch itecture describes th e gen eral con n ectivity of th e trabeculae, th e m ean th ickn ess of in dividual trabeculae, th e m ean spacin g between trabeculae, an d th e n um ber of th e trabeculae. Ch an ges in th e geom etry can in fluen ce th e load an d stresses to th e bon e an d, th erefore, affect bon e stren gth . At th e m icroarch itectural level, h orizon tal trabeculae form a network conn ecting various trabeculae, stren gth en in g the bon e against compressive forces in th e sam e way as cross-struts of a three-legged chair contribute to the stability of the chair (Fig. 6.4). Destruction of these con n ectin g trabeculae, wh ich is seen in postm en opausal osteoporosis, results in in creased fragility of th e skeleton . Measurem ent of bone geom etry (m acroarchitecture) can be don e from th e plain radiograph s, wh ereas m easurem ent of m icroarchitecture is obtained from bon e biopsy. Bon e biopsy yields various h istom orph om etric param eters th at in volve th e quan titative an alysis of un decalcified bon e. Th e param eters of skeletal rem odellin g are expressed in term s of trabecular volum e/ tissue volum e, trabecular n um ber, trabecular separation , an d m arrow star volum e (a m easure of porosity). Currently, th ese param eters can

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Figure 6.4 The cross-struts of a

three-legged chair are important in providing the stability of the chair. Similarly, the horizontal trabeculae provide structural support to the bone.

be obtain ed by usin g th ree-dim en sion m icrocom puted tom ography or h igh -resolution m agn etic reson an ce im agin g.

METABOLIC DISORDERS OF BONE OSTEOPOROSIS O steoporosis is a con dition ch aracterized by decreased bon e m ass, m icroarch itectural deterioration , an d ultim ately in creased bon e fragility resultin g in an in creased risk of fracture. It is the m ost prevalent m etabolic bon e disease an d is a source of sign ifican t m orbidity an d m ortality as well as trem en dous cost. Curren t estim ates suggest th at osteoporosis affects m ore th an 200 m illion people worldwide, and the problem con tin ues to grow. It is projected that the worldwide inciden ce of hip fractures will increase from 1.26 m illion in 1990 to 2.6 m illion by 2025 an d 4.5 m illion by 2050.

Epidemiology In th e Un ited States alon e, an estim ated 10 m illion people older th an 50 are affected an d an oth er 34 m illion are at risk. Th e fracture in ciden ce am on g affected Am erican s is approxim ately 1.5 m illion per year. O f th ese, approxim ately 700,000 are vertebral fractures, 300,000 are h ip fractures, an d 200,000 are wrist fractures. Wom en are affected m ore com m on ly th an m en . In addition , m en are n oted to h ave a relatively later on set of disease, up to on e decade on average. Th e lifetim e probability of hip fracture is 14% in Caucasian wom en an d 5% to 6% in Caucasian m en . O th er eth n ic groups can vary con siderably in term s of th eir in ciden ce of fracture. African Am erican s have a con siderably lower rate of fracture than do Cau-

casian s, with on ly 3% an d 6% for m en an d wom en , respectively. The risk of fracture in Mexican Am erican wom en has been n oted to be in term ediate, greater th an th at of African Am erican s but less th an th at of Caucasian s. Th ere is sign ifican t m orbidity an d m ortality associated with low-en ergy fractures. Vertebral fractures m ay be a source of ch ron ic an d disabling pain. Approxim ately oneth ird of patien ts with h ip fractures are disch arged to n ursing hom es, and the 1-year m ortality rate am ong patients with h ip fracture is approxim ately 20%. Th us, orth opaedic surgeons m ust be in creasin gly suspicious of this disease in certain patien t dem ograph ics, ach ieve a firm un derstan ding of the pathogenesis of osteoporotic bon e and the condition s th at result in bon e fragility, an d becom e fam iliar with th e curren t strategies for diagn osis, preven tion , an d treatm ent of osteoporosis.

Classification Osteoporosis is classically divided into two categories, prim ary and secondary. Prim ary osteoporosis is the result of predictable physiologic ch an ges in BMD, wh ich can result in clinical disease in som e patients. It m ay be on e of two types. Type I, or postm en opausal osteoporosis, is associated with the relative estrogen deficit seen in postm en opausal wom en. The lack of estrogen seen in the years followin g m en opause is associated with an accelerated rate of bon e loss. Th is is th e m ost com m on form of osteoporosis in th e gen eral population, and it is from this subgroup that m ost of our current data on osteoporosis are derived. Type II, or sen ile osteoporosis, is seen in m en an d wom en alike older than 70. It is the result of age-related decline in BMD, wh ich is com m on to both m en an d wom en begin n in g in m idlife. While wom en un dergo accelerated BMD loss in the perim en opausal years, the rate of loss declines


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Figure 6.5 Bone mineral density (BMD) steadily

increases from birth until it peaks during the third decade. With age, BMD gradually decreases in both men and women; however, women experience accelerated bone loss during the first few years after menopause.

in the years that follow and by the age of 60, m en and wom en h ave sim ilar rates of declin e (Fig. 6.5). Secon dary osteoporosis is defin ed by th e presen ce of som e pre-existin g disease process or other causative factor th at causes a secon dary declin e in BMD (Table 6.2). Approxim ately 20 –30% of osteoporotic wom en an d 66% of osteoporotic m en h ave th eir osteoporosis secon dary to som e underlyin g con dition . Therefore, patien ts with secon dary osteoporosis m ust be iden tified because defin itive treatm ent of the un derlying cause is necessary to prevent further bone loss, an d th us lower the risk of fracture.

CAUSES OF SECONDARY OSTEOPOROSIS

Osteoporosis m ay also be categorized into two form s based on bon e turn over rate: low-turn over an d h igh turn over osteoporosis. Th e low-turnover state describes a situation in wh ich norm al bone hom eostasis is altered by decreased osteoblast activity; however, the osteoclast activity rem ain s n orm al. Low BMD in th is settin g, th erefore, is a result of reduced bone form ation. Conversely, the high-turnover state is characterized by increased activity of both osteoblasts an d osteoclasts. However, osteoclasts are activated to a greater extent. The bone rem odelin g process is sh ifted toward bon e resorption , resultin g in an im balan ce of bon e turn over th at causes osteoporosis. High-turn over osteoporosis is the m ost com m on form and appears at m en opause, wh ereas low-turn over osteoporosis occurs followin g drug in terven tion s in cludin g ch em oth erapy, steroids, an d prolon ged bisph osph on ate use.

Hormone excess ■ Parathyroid (primary or secondary) ■ Thyroid ■ Cortisol

Diagnosis

TABLE 6.2

Hormone deficiency ■ Estrogen (premenopausal or postmenopausal) ■ Testosterone Diseases ■ Inflammation (rheumatoid arthritis, ulcerative colitis) ■ Tumor or malignancy (multiple myeloma, lymphoma) ■ Collagen vascular disease ■ Renal osteodystrophy ■ Others (liver diseases, immobilization) Drugs ■ Corticosteroids ■ Thyroxine ■ Alcohol ■ Anticonvulsants (barbiturates, phenytoin) ■ Anticoagulants (heparin, coumadin) ■ Antimetabolites (methotrexate, cyclosporin) (From Yue J, Guyer R D, Johnson JP, et al. The Comprehensive Treatment of the Aging Spine: Minimally Invasive and Advanced Techniques, Philadelphia, PA: Elseiver 2010 with permission).

To date, DEXA is considered the gold standard in the m easurem en t of BMD an d diagnosis of osteoporosis. DEXA scan nin g as a part of osteoporosis screening typically in volves scans of the h ip, lum bar spine, and occasionally the distal radius. Results for a given patien t are com pared to th e average values for age-m atch ed con trols an d youn g n orm al patien ts at th eir peak BMD, an d from th ese comparison s th e Z-scores and T-scores are derived, respectively. T-scores between 1 an d 2.5 stan dard deviation s below th e n orm (between –1 to –2.5) are diagnostic for osteopenia, wh ile scores equal to or below –2.5 are diagnostic for osteoporosis. For patients younger th an 35, diagnosis of osteoporosis is dependent on ly on the Z-score. A Z-score of less than – 1.5 is sign ifican t in th at it m ay be in dicative of a secon dary cause of osteoporosis. Early detection of osteopen ia an d osteoporosis with DEXA screen in g is an importan t m ean s of reducin g th e

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risk of fracture an d associated m orbidity. However, universal screenin g is neith er practical n or feasible. The In tern ation al Society for Clin ical Den sitom etry (ISCD) advocates DEXA screen in g for any patien t wh o is 1. a fem ale aged 65 or older; 2. a postm enopausal fem ale younger than 65 who has clin ical risk factors for fracture, such as low body m ass in dex, prior fracture, or use of a high-risk m edication; 3. a wom an during the m enopausal tran sition with clinical risk factors for fracture; 4. a m ale aged 70 years or older; 5. a m ale aged 70 years or younger with clin ical risk factors for fracture; 6. an adult with a history of a fragility fracture; 7. an adult with an illness known to cause bone loss or low BMD; 8. an adult taking a m edication known to cause bone loss or low BMD; 9. any patient being considered for pharm acologic treatm en t of bon e loss; 10. any patien t curren tly bein g treated for low BMD in order to m on itor th e treatm en t effect; or 11. any patien t not receiving therapy in whom evidence of bon e loss would lead to ph arm acologic treatm en t. In addition to these guidelin es, it is important to take in to accoun t oth er factors th at m ay in crease a patien t’s propen sity for low BMD or fracture. Patien ts with poor gen eral h ealth , alcoh olism , dem en tia, frailty, recen t discon tin uation of estrogen replacem en t th erapy, or lon g-term h istory of estrogen deficien cy sh ould be con sidered for DEXA scan n in g even if they do n ot fit into the ISCD criteria.

Evaluation for Osteoporosis O n ce diagn osed with osteoporosis, a com plete m edical history should be obtain ed with particular atten tion to the risk factors for osteoporosis. The physical exam ination sh ould be perform ed particularly of th e spin e region . Heigh t sh ould be m easured an d compared with th e greatest kn own h eigh t to determ in e h eigh t loss, wh ich is an in dicator of vertebral compression fractures. Balan ce an d walkin g gait sh ould be observed in each in dividual. Th e assessm en t of fun ction al balan ce is perform ed by using the single lim b stance test and the 6-m inute walking test. As osteoporosis is a clinically silent condition, diagnostic im agin g m odalities such as plain radiograph s, com puted tom ography (CT), or m agn etic reson an ce im agin g (MRI) m ay often be th e first study available for patien ts who present with a fragility fracture. Two-thirds of vertebral fractures are clinically silen t an d are diagnosed on ly after diagn ostic im agin g is employed. Th in cortices an d gen eralized decrease in radio-opacity are two m ajor in dicators of decreased bon e den sity an d, wh en seen in a patien t with

a low energy fracture, should alert clin icians to the likely diagn osis of osteoporosis.

Laboratory Investigations In addition to diagn ostic im agin g, som e routin e tests sh ould be perform ed to obtain baseline values as part of the initial workup. These include complete blood cell count with differen tial, urin alysis, an d blood ch em istry profiles with serum calcium an d ph osph ate. Because vitam in D deficien cy is very com m on am on g elderly population s, with a prevalen ce of approxim ately 50%, all elderly patien ts sh ould be tested for vitam in D deficiency by m easurin g levels of 25-hydroxy-vitam in D. If low, adequate vitam in D supplem en tation is en couraged. Vitam in D deficien cy, as defined by a serum 25-hydroxy-vitam in D of less than 20 n g per m L, is associated with poor m uscle fun ction as well as m in eralization defects. Markers of bon e turn over are important to indicate the status of bone m etabolism . Measurem en t of bone m arkers is helpful for following a patien t’s respon se to treatm en t over tim e. Th erefore, it is advisable to get a baseline value as part of the initial workup. Wh en secon dary osteoporosis is suspected on th e basis of clin ical fin dings or because th e patient is relatively young an d presented with fragility fracture, specific tests sh ould be con sidered to evaluate contributing causes that m ay require additional m edical attention. These include basic laboratory investigation of a complete blood cell count with differen tial, eryth rocyte sedim en tation rate, serum calcium and ph osph ate levels, liver fun ction tests, thyroidstim ulatin g h orm one level, testosteron e level in m en, and a serum protein electroph oresis if myelom a is con sidered (Table 6.3). When abnorm alities are detected, th e patient sh ould be referred to a specialist for furth er evaluation and specific treatm ent.

Assess for Risk of Falls and Fracture Risk Certain com orbidities associated with the aging population m ay predispose a patien t to falls, such as unsteady gait, use of sedative or hypn otic m edication s, an d im paired visual or n eurom uscular function . By identifying patients at particularly h igh risk for falls early in th e course of treatm en t, it is possible to prevent a subsequent fracture. It is well recogn ized th at th e fracture rate is h igh est am on g osteoporotic patien ts ( T-score − 2.5 or below). However, a m uch larger proportion of patients reside in the range of osteopen ia (below − 1.0 to above − 2.5). Consequently, m ore total fractures occur in th is osteopen ic group (55% of h ip fractures). To adjust for the disparity, a new vehicle called the Fracture Risk Assessm ent Tool (FRAX) has been developed th at adds addition al risk factors to th e calculation an d offers a better assessm en t of fracture risk th an DEXA scan n in g alon e. This in strum en t calculates th e patien t’s 10-year fracture risk on the basis of (a) age, (b) sex, (c) weigh t, (d) h eigh t, (e) previous fracture, (f) paren t with a fractured h ip,


105

TABLE 6.3

LABORATORY INVESTIGATIONS FOR SECONDARY OSTEOPOROSIS Medical Diseases Endocrine ■ Hyperparathyroidism ■ ■ ■

Hyperthyroidism Hypogonadism Diabetes

Diagnostic Study Serum calcium, serum phosphate, parathyroid hormone levels TSH, T3, free T4 LH, FSH, estrogen, testosterone (men) Blood glucose

GI disorders ■ Crohn’s disease, ulcerative colitis

CBC, ESR, CRP, serum albumin, colonoscopy

Liver disease ■ Primary biliary cirrhosis, chronic active hepatitis

Liver function test, antimitochondrial antibody, antibody for hepatitis A, B, and C

Bone marrow disorders ■ Multiple myeloma, leukemia, lymphoma Collagen vascular disease ■ Osteogenesis imperfecta, Ehlers–Danlos syndrome, Marfan syndrome Others ■ Rheumatoid arthritis ■ Renal failure

CBC with differential, serum calcium, serum protein electrophoresis Genetic testing for collagen defects

CBC, ESR, CRP, rheumatoid factor BUN, creatinine

TSH, thyroid-stimulating hormone; LH, luteinizing hormone; FSH, follicle-stimulating hormone; CBC, complete blood cell count; ESR, erythrocyte sedimentation rate; CRP, c-reactive protein; BUN = blood urea nitrogen. (From Yue J, Guyer R D, Johnson JP, et al. The Comprehensive Treatment of the Aging Spine: Minimally Invasive and Advanced Techniques, Philadelphia, PA: Elseiver 2010 with permission).

(g) current sm oking, (h) use of glucocorticoids (i) presence of rh eum atoid arth ritis, (j) secon dary osteoporosis (k) alcoh ol use (≥ 3 drin ks/ day), and (l) BMD at th e fem oral neck area. Calculated risk m ay serve as a h elpful guide in therapeutic decision m akin g for patients at risk of fracture. FRAX m odels for th e Un ited States, Un ited Kin gdom , an d a n um ber of oth er coun tries are available on th e In tern et at http:/ / www.shef.ac.uk/ FRAX/ in dex.h tm .

Treatment Nonpharmacologic Treatment A m ultidisciplin ary approach is critically importan t in th e m anagem ent of osteoporosis. Nonpharm acologic treatm en t is used concurren tly with pharm acologic therapy to optim ize fracture risk reduction . Th us, every patien t sh ould be con sidered for n onph arm acologic m an agem en t. Com m on ly used nonpharm acologic treatm en ts include, but are not lim ited to, calcium an d vitam in D supplem entation, fall preven tion , an d balan ce an d exercise program s. A negative calcium balance or suboptim al levels of 25-hydroxy-vitam in D m ust be addressed first before any ph arm acologic in terven tion is un dertaken sin ce th ese represen t a con stan t impetus for bon e dem in eralization an d decreased bon e den sity an d stren gth . Th e recom m en ded daily calcium requirem en t is between 1200 an d 1500 m g per day. In addition to en couragin g dietary sources of cal-

cium , calcium supplem en tation can be carried out with a n um ber of form ulations, th e m ost com m on of which are calcium carbonate and calcium citrate. Absorption of calcium carbon ate is dependent upon gastric pH and can be comprom ised in patients taking proton pump inhibitors, wh ile calcium citrate is absorbed at all pH levels. In addition , calcium citrate bin ds to oxalate, reducin g its in testin al absorption , an d citrate in urin e in h ibits crystal form ation , thus reducing the incidence of kidn ey stones. Th e curren t recom m en ded dosages of vitam in D 3 from the Institute of Medicin e are 200 to 600 IU per day. However, m any experts con sider th ese recom m en dation s to be too low, an d suggest th at th e m in im um adult in take should be 1000 to 2000 IU per day. Th e appropriate am oun t of vitam in D in take sh ould be evaluated by m on itorin g 25-hydroxy-vitam in D level and serum PTH. For patients with m arkedly low levels of vitam in D, 50,000 intern ation al un its of vitam in D 2 can be taken orally on ce a week or every oth er week for 6 to 8 weeks, followed by a m ain ten an ce dose of 1000 to 2000 IU of vitam in D 3 per day. Toxicity is rare even if a dosage of 10,000 IU per day is given for up to 5 m onths.

Pharmacologic Treatment Th e ph arm acologic agen ts curren tly available are com m only divided into two groups: an tiresorptive and anabolic. Antiresorptive agen ts have been developed to

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address th e h igh -turn over state. Th ese in clude estrogen , selective estrogen receptor m odulators (SERMs), calciton in , an d bisph osph on ates. Th e an abolic agen t, parathyroid horm one, provides active building of bone m ass an d has been suggested to treat th e low-turn over state. Estrogen Estrogen is an an ti-osteoporotic agen t that has been shown to in crease bon e m ass an d th us decreases th e risk of vertebral an d h ip fracture by approxim ately 30% to 40% as compared with patients taking placebo. Estrogen, however, has been foun d to increase rates of stroke and deep vein throm bosis, while com bined estrogen and progesterone therapy is associated with increased risks of cardiovascular disease, breast can cer, dem en tia, an d gall bladder disease. As a consequence, estrogen is m ainly used in the early postm en opausal period to treat postm en opausal syn drom e an d then lowered to the lowest dose that effectively controls symptom atology. The risks associated with estrogen form ulation s preclude th eir use as prim ary agen ts in th e treatm en t of osteoporosis. Selective Estrogen Receptor Modulators Selective Estrogen Receptor Modulators (SERMs) are a class of agen ts th at bin d to estrogen receptors. Th ey h ave a sign ifican t effect on breast tissue an d bon e cells; h owever, th ey act as an tagon ists in th e oth er receptor sites. Of th e SERMs currently bein g used for clinical settings, only raloxifene has been approved for the prevention and treatm en t of osteoporosis. Early data suggest th at raloxifen e decreases th e risk of breast cancer by 70%, which h as m ade raloxifene a preferred agen t am on g osteoporotic patien ts with breast can cer risk. Although raloxifene has been shown to reduce the risk of vertebral fracture, there was no significant reduction in th e overall risk of n on vertebral fracture. In addition , by stim ulatin g estrogen receptors, raloxifen e in creases the risk of pulm onary em boli and throm boph lebitis and m ay cause profoun d postm en opausal symptom s. Th erefore, clinicians m ust weigh th e benefits of the reduced risks of vertebral fracture and invasive breast cancer again st the in creased risks of ven ous throm boem bolism and fatal stroke wh en considerin g th is agen t for osteoporosis m anagem en t. Calcitonin Calciton in is available as both a paren teral in jection an d a nasal spray. The intranasal spray is the m ost com m only used form ulation due to its superior com plian ce an d ease of use. Calciton in reduces th e risk of vertebral fracture; h owever, th ere is on ly a m odest in crease in BMD. In addition , calciton in treatm ent sh ows no benefit for reducing the risk of h ip an d oth er n on vertebral fractures. Th ere is som e data suggestin g the analgesic effect of calcitonin . Alth ough there is a hypoth esis th at calciton in -in duced an algesia m ay be m ediated by in creased beta-en dorph in s an d m ay directly affect pain receptors in th e cen tral n ervous system , th e ex-

act m echanism is still unkn own. Therefore, the current in dication for calciton in treatm en t is for alleviatin g pain ful vertebral compression fractures. It sh ould be discon tinued as soon as pain has been controlled, since other pharm acologic agents are m ore effective in preventin g future fractures. Bisphosphonates Bisphosph onates have been a m ain stay of osteoporosis treatm ent for the past 30 years. The chem ical structure of th is class of drugs is closely related to th at of in organ ic pyroph osph ate (PPi), a com m on byproduct of n um erous synth etic reaction s, wh ich has been shown, in vivo, to have a h igh affin ity for hydroxyapatite an d an associated in h ibitory effect on calcification . Th e bisph osph on ates share th is h igh affin ity for hydroxyapatite an d as a result are rapidly absorbed an d retain ed in bon e. O n ce th ere, th ey inhibit bone resorption by inducing osteoclast apoptosis. Bisph osphon ates h ave been proven effective for th e reduction of fracture risk in patien ts with osteoporosis an d a n um ber of oth er m etabolic bon e diseases. Data from th e Fracture In tervention Trial, a m ulticenter random ized control study, revealed a relative reduction in risk of 47% for h ip fractures an d 55% for clin ical vertebral fractures in patients taking alen dron ate when compared to placebo. Their efficacy an d ease of use h ave led to widespread use of th ese agen ts as first-line therapy for osteoporosis and osteopen ia. Both oral an d in traven ous form ulation s are available (Table 6.4). Wh ile oral adm inistration m ay be m ore conven ien t, in travenous adm in istration is often utilized for patients with severe gastrointestinal complaints after oral intake, a h istory of severe gastroesph ageal reflux or peptic ulcers, or disorders th at com prom ise absorption such as sh ort bowel syn drom e or Crohn ’s disease. Adverse effects of bisphosphonates include flu-like sym ptom s, especially with intravenous adm inistration, severe gastroesophageal reflux, and, rarely, osteon ecrosis of th e jaw. Furth erm ore, by in h ibitin g bon e rem odelin g, bisph osph on ates slow fracture h ealin g an d sh ould be avoided or discon tin ued in th e settin g of acute fracture. In addition , th ere h as been a growin g con cern over th e years regardin g th e poten tial for bisph osph on ates to in duce a frozen bon e syndrom e wherein prolonged oversuppression of bon e rem odeling results in deleterious effects on bone quality, wh ich m ay culm in ate in low-en ergy fractures (Fig. 6.6). Several reports in the literature m ake reference to an association between long-term alendronate use an d atraum atic or low-en ergy fem oral shaft fractures. Although a causal relation sh ip h as n ot been dem on strated, th ese fin dings, in com bination with anim al studies dem onstratin g reduced repair an d accum ulation of m icrodam age in an im als treated with alendronate, suggest that impaired bone turn over m ay put patients at risk for low-energy fractures. Non eth eless, bisph osph on ates rem ain on e of th e m ost poten t agen ts available for th e reduction of fracture risk in osteoporotic patien ts. O n e solution th at h as been adopted


107

TABLE 6.4

BISPHOSPHONATES RECOMMENDED TO TREAT OSTEOPOROSIS Generic Name

Trade Name

Recommended Dose

Route of Administration

Alendronate

Fosamax

Oral

Risedronate

Actonel

Ibandronate

Boniva

Zoledronic acid

Reclast

10 mg/d 70 mg/wk 5 mg/d 35 mg/wk 75 mg/2 wk 150 mg/mo 150 mg/mo 3 mg/3 mo 5 mg/y

Instructions

Oral

Oral bisphosphonates: take with 8 oz of water and wait at least 30 min in an upright position before eating or drinking anything

Oral Intravenous Intravenous

Intravenous bisphosphonates: infusion over 15 to 45 min and coadministration with Benadryl and Tylenol

All bisphosphonates: precaution in patients with severe renal insufficiency or hypocalcemia.

by m any clinicians is to m on itor the effect of an tiresorptive therapy th rough the use of serum or urine m arkers of bon e turnover such as NTx. Regular m onitorin g of NTx levels m ay allow th e clinician to titrate anti-resorptive therapy to a desired level of action an d preven t oversuppression of bon e turn over by h altin g adm in istration of an tiresorptive m edications in patients already in a low-turn over state.

Teriparatide Teriparatide, a recom binant fragm ent of hum an PTH, represen ts a relatively n ew an d powerful agen t for th e treatm ent of osteoporosis. It is th e only anabolic agent approved for th e treatm en t of osteoporosis in the United States. Teriparatide is adm in istered as a daily subcutan eous in jection. Wh ile con tinuous adm in istration of PTH, as seen in prim ary hyperparathyroidism , results in in creasin g bon e resorption , by m ech an ism s th at rem ain un clear, th e adm inistration of low-dose interm ittent PTH in the form of teriparatide acts as a powerful in ducer of bon e form ation . Wh ile cost is curren tly a m ajor lim itin g factor in th e use of teriparatide as a first-lin e th erapy for osteoporosis, it rem ains an important agent for the treatm ent of patients with following con ditions: 1. patien ts with low-turn over osteoporosis; 2. patients wh o have been on bisph osph onates and still have fragility fracture; 3. patients with declining bon e densities while taking bisph osphonates Teriparatide h as been associated with osteogen ic sarcom a wh en given in extrem ely h igh doses to laboratory rats. As such , its use is con train dicated for any pediatric patien t or a patien t with a h istory of recen t radiation th erapy, as both m ay be associated with an in creased incidence of osteogenic sarcom a. Teriparatide should be discon tin ued after 2 years of treatm en t. After th at, bisph osph on ate th erapy sh ould be in itiated to m ain tain its results.

RICKETS AND OSTEOMALACIA Figure 6.6 Plain radiograph anteroposterior view showing

femoral shaft fracture. Fracture after prolonged treatment with bisphosphonates is characterized by (A) simple or transverse fracture; (B) beaking of the cortex on one side; (C) hypertrophied diaphyseal cortices; and (D) result from minimal or no trauma.

Rickets is a clinical condition in which there is inadequate m ineralization of th e growing skeleton, an d thus by defin ition occurs solely in ch ildren . Con versely, osteom alacia is a defect of m ineralization that occurs after cessation of

108


the skeletal growth. While importan t distinctions exist between th ese two diseases, th ey arise from sim ilar etiologies an d th us th ere is m uch overlap between th e clin ical, radiograph ic, an d h istologic presen tation s of each . Rickets an d osteom alacia h ave a relatively h igh er prevalen ce in population s th at receive lim ited sun ligh t th rough out th e year, or wear cultural attire th at precludes ultraviolet exposure to th e skin , especially in parts of Asia an d th e Middle East. In Un ited States, it is estim ated th at 25% of elderly people have chronically low levels of vitam in D because of un dernourishm ent and low exposure to sunligh t. In addition , th e absorption of vitam in D from th e gastroin testin al tract is reduced in th is particular age group.

Etiology of Rickets and Osteomalacia Bone m ineralization depends on th e presen ce of calcium , ph osph ate, an d alkalin e ph osph atase en zym e. Th erefore, any con dition th at reduces th e availability of serum calcium , ph osphate, or alkaline phosphatase enzym e will result in rickets or osteom alacia (Table 6.5). Although th ere are a n um ber of causes for rickets an d osteom alacia, m ost of th em sh are sim ilar h istologic ch an ges, as well as clin ical an d radiograph ic appearan ces. Nutrition al rickets an d osteom alacia are th e oldest an d best kn own form s of hypocalcem ic disorders; h owever, th e prevalen ce rate h as n ow been greatly reduced in developed countries. Low levels of vitam in D results in decreased absorption of calcium across the intestinal tract, causin g a decline in the concentration of serum calcium . This reduced serum calcium triggers a compen satory increase in th e synthesis an d secretion of PTH by th e parathyroid glands. PTH secretion m ay elevate the serum calcium concen tration back to n orm al by th ree m ajor m ech an ism s: (a) in creasin g calcium reabsorption in th e proxim al tubule of the kidney; (b) stim ulatin g th e hydroxylation of 25-hydroxy-vitam in D

TABLE 6.5

CAUSES OF RICKETS AND OSTEOMALACIA Low serum calcium Nutritional rickets ■ Vitamin D deficiency ■ Dumping syndrome ■ Chronic liver disease ■ Chronic bowel disorder ■ Anticonvulsant medications Vitamin D–resistant rickets ■ Type 1–dependent (1α-hydroxylase deficiency) ■ Type 2–dependent (end organ insensitivity to vitamin D) Renal tubular acidosis Low serum phosphate X-linked hypophosphatemia Low serum alkaline phosphatase Hypophosphatasia

to th e m ore active 1,25-dihydroxy-vitam in D (wh ich facilitates intestinal absorption of calcium ); and (c) enhancing the osteoclast-m ediated resorption of bone. The increased parathyroid activity reduces serum ph osph ate as a result of decreased tubular reabsorption of ph osph ate. Th is results in hyperphosphaturia and hypophosphatem ia. Th e bone ch anges are related to a decrease in the available calcium an d phosphate needed to synthesize calcium hydroxyapatite and a secondary hyperparathyroidism , which causes osteoclastic destruction of th e existin g bony structure. Low levels of vitam in D m ay also occur in persons with in adequate dietary in take, gastroin testin al m alabsorption (celiac sprue, status post gastrectomy, and chronic pancreatitis), or ch ronic low exposure to sunlight. Certain anticonvulsants m ay accelerate th e catabolism of vitam in D in the liver, causin g decreased levels in the serum . Th ere are two form s of vitam in D –resistan t rickets secon dary to in h eren t defects of th e vitam in D m etabolic path way, design ated as type 1 – an d type 2 –depen den t rickets. Type 1 –depen den t rickets refers to a deficien cy of th e 1αhydroxylase en zym e th at con verts 25-hydroxy-vitam in D to 1,25-dihydroxy-vitam in D, wh ereas type 2 –depen den t rickets is an in h eren t defect in th e vitam in D in tracellular receptor. As a result of th is en d organ in sen sitivity in type 2 – depen den t rickets, th e circulatin g level of 1,25-dihydroxyvitam in D is exceedin gly high. Interestingly, there is eviden ce th at certain tum ors m ay secrete a factor th at causes ren al proxim al tubule deran gem en t, resultin g in reduced vitam in D synthesis or phosphate deficiency, which can also lead to skeletal dem ineralization. Wh ile vitam in D deficien cy is th e prim ary etiology of rickets an d osteom alacia, oth er less com m on causes of skeletal dem in eralization exist. X-lin ked hypoph osph atem ia is th e m ost com m on in h erited etiology for rickets. Th e disease causes isolated ren al ph osph ate wastin g, leading to hypophosphatem ia. The specific treatm en t for this condition is oral adm in istration of phosphate. Renal tubular abnorm alities such as renal tubular acidosis and Fancon i syn drom e cause renal wasting of m ineral con ten ts including ph osph ate and, therefore, result in a vitam in D – resistan t form of rickets/osteom alacia. Fin ally, a deficien cy in alkalin e phosphatase enzym e produces abn orm al m ineralization of bon e an d th us creates clin ical features th at overlap with rickets in th e ch ild an d osteom alacia in th e adult.

Clinical Presentation Th e developin g skeleton requires an abun dan t source of calcium and phosphate in order to properly m ineralize during periods of rapid bone growth. In children with rickets, th e process of m in eralization can n ot keep pace with the production of n ew osteoid. The result is a relatively dem in eralized skeleton th at lacks th e com pressive stren gth of n orm al bon e, an d subsequen tly develops con siderable deform ity in a predictable pattern . Weigh t-bearin g bon es


109

TABLE 6.6

BIOCHEMICAL CHANGES IN RICKETS AND OSTEOMALACIA Biochemical Changes Etiology Nutritional rickets ■ Vitamin D deficiency ■ Dietary phosphate deficiency Type 1 dependent Type 2 dependent X-linked hypophosphatemia Hypophosphatasia

Ca2+

PO4 3-

AP

PTH

25-OHVit D

1,25-OH2 Vit D

Urine Ca2+

Associated Findings

N, ↓

↓

↑

↑

↓

↓

↓

Low diet, chronic bowel disease (i.e., Crohn’s disease) Phosphate-binding antacid abuse, aluminum toxicity No alopecia Alopecia, with near-total loss of body hair Decreased renal tubular absorption of phosphate Failure to thrive, early loss of teeth, craniosynostosis

N

↓

↑

N

N

N

N

↓ ↓

↓ ↓

↑ ↑

↑ ↑

N N, ↑

↓↓ ↑↑

↓ ↓

N

↓

↑

N

N

N

N

↑

↑

↓↓

N

N

N

↑

Ca2+ , calcium; PO4 3− , phosphate; AP, alkaline phosphatase; PTH, parathyroid hormone; 25-OH-Vit D, 25-hydroxyvitamin D; 1,25-OH2 -Vit D, 1,25-dihydroxy-vitamin D; ↑ , increase; ↓ , decrease; N, normal. (Adapted from Mankin HJ. Metabolic bone disease. In: Jackson DW, ed. Instructional Course Lectures, volume 44. American Academy of Orthopaedic Surgeons, 1995:10.)

are the m ost noticeably affected, such as the forearm s in infan ts learn in g to crawl. O lder ch ildren wh o walk m ay suffer varus or valgus deform ity of the lower extrem ity. Children m ay be irritable an d complain of bone pain , dental caries, m uscle aches, and weakn ess exacerbated by activity. Min eralization is of particular importan ce at th e epiphyseal plate, wh ere a zon e of calcification precedes th e replacem en t of cartilage by n ewly form in g bon e. Patien ts with rickets can n ot efficien tly calcify th e cartilage in th is region , resultin g in a m arked profusion of cells in th e n on calcified zone of hypertrophy. This presen ts clinically as a widen in g of th e epiphyses, m ost n oticeably in th e wrists, elbows, kn ees, an d an kles. Oth er com m on fin din gs on physical exam in ation th at result from bony dem in eralization in clude shortness of stature, frontal bossing, a soften ing of th e skull, prom inence of the costochondral junctions (the so-called rachitic rosary), and a thoracic kyphosis. Th e clin ical presen tation of adults with osteom alacia is sim ilar in m any respects to that of ch ildren with rickets. Bone pain, m uscle ach es, an d weakness are typical com plain ts. O steom alacic patien ts m ay also presen t with polyarth ralgias, which m ay be m istaken for rheum atoid arthritis. O steom alacia occurs by definition after the skeleton has already m atured; therefore, som e of the characteristic findings in rickets (bowing deform ities of the lim bs, widening of th e epiphyses) are n ot n ecessarily foun d in osteom alacic patien ts.

Laboratory Investigations A variety of etiologies m ay cause th e skeletal dem in eralization typical of rickets and osteom alacia, and each is associated with a characteristic set of biochem ical derangem ents

(Table 6.6). Depen din g on th e prim ary m etabolic in sult, the patient m ay have abnorm al serum concentrations of calcium , phosphate, alkaline ph osph atase, PTH, or vitam in D. In n utrition al deficien cies, 25-hydroxy-vitam in D is th e m ost reliable m arker. Recogn ition of th ese pattern s is h elpful in m akin g th e diagn osis an d in directin g subsequen t m an agem en t of th e patien t’s m etabolic deficien cy.

Radiographic Features Plain radiograph s of th e patien t with suspected osteom alacia or rickets are h elpful in ch aracterizin g th e exten t of skeletal dem in eralization . Patien ts with rickets classically sh ow widen in g of th e epiphyseal plates, with cuppin g an d flaring of the distal ends of the lon g bones. Cortical thinning is apparent, and a “ground-glass’’ appearance of the cancellous bon e m ay be presen t secon dary to th e layers of un m ineralized osteoid being deposited around the bony trabeculae. Focal deposition s of un m in eralized osteoid m ay also be apparent on plain radiographs as radiolucent areas exten din g perpen dicularly across th e cortex. Th ese “pseudofractures’’are kn own as “Looser’s lin es” an d ten d to occur on th e con cave aspect of lon g bon es, at th e m edial fem oral n eck, in ferior to th e lesser troch an ter, on th e isch ial and pubic ram i, at th e posterior aspect of th e rib, on th e clavicles, an d at th e lateral aspect of the scapulae (Fig. 6.7). In cases wh ere th e presen ce of Looser’s lin e is question able, a bon e scan m ay be h elpful in iden tifyin g th e cortical m in eral defect. Looser’s lin es are ch aracteristic of both rickets and osteom alacia and m ay propagate in to a true fracture if th e patien t is left un treated. Bon e scan an d MRI can detect fractures not visible on radiographs.

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oral adm in istration of ph osph ate an d th e active form of vitam in D. Th ose with on cogen ic causes of skeletal dem in eralization should have th eir tum ors completely rem oved, even if ben ign . Patien ts with ren al tubular acidosis or oth er ren al tubular abn orm alities th at causes loss of bon e m in eral con ten t can be treated with ph osph ate replacem en t an d supplem ental vitam in D. Electrolyte im balances need m onitorin g an d treatm ent, and the underlying renal disease sh ould also be treated if possible. Fin ally, th e provider sh ould con sider chan ging any drugs or other m edical interven tion s th at m ay cause iatrogen ic skeletal dem in eralization.

RENAL OSTEODYSTROPHY Renal osteodystrophy is a path ologic bone condition in wh ich th e prim ary cause of th e disorder is ch ron ic ren al failure. Because of th e adven t of m odern m edical treatm en t, patien ts with ch ron ic ren al disease are livin g lon ger an d are m ore physically active. Th erefore, the chance of this group of patien ts presen tin g to th e orth opaedic com m un ity eith er for elective surgery or in an em ergency traum a situation increases. Figure 6.7 Plain radiograph of the ulna of a patient with rickets

showing pseudofracture at the medial border of the diaphysis, also known as Looser’s line, umbauzonen, or Milkman’s pseudofracture. (Courtesy of Bernard Ghelman, MD.)

Plain radiograph s in osteom alacia often look n orm al, an d unless a Looser’s line is identified the patient m ay be m isdiagn osed with osteoporosis. Som e ch aracteristic radiograph ic fin din gs com m on ly foun d in osteom alacia include an overall reduction in bone density, and a coarsen in g of th e trabeculae, or a groun d glass appearan ce to the spine.

Treatment Atreatm ent strategy for the patient with rickets or osteom alacia sh ould be selected to address th e un derlyin g etiology of skeletal dem in eralization . In patien ts with n utrition al rickets, calcium and vitam in D supplem entation is appropriate. A com m on dosin g regim en is ergocalciferol 50,000 IU on e to two tim es per week, with 1,000 to 1,500 m g of calcium per day. The treatm ent should last from 6 m onths up to 1 year. If th e patien t h as a syn drom e of gastroin testinal m alabsorption , an in jectable form of vitam in D sh ould be con sidered. Patien ts with depen den t rickets sh ould be carefully studied and treated with 1,25-dihydroxy-vitam in D for both type 1 – an d type 2 –depen den t form s. However, treatm en t with h igh doses of vitam in D produces a variable clinical response in type 2 –depen den t patien ts. Th e specific treatm en t for patien ts with X-lin ked hypoph osph atem ia is

Pathophysiology Kidneys are the vital organs for regulatin g calcium hom eostasis. Th e proxim al con voluted tubule is th e site th at produces 1,25-dihydroxy-vitam in D. Th is h orm on e is a prim e regulator of in testin al calcium absorption an d provides th e feedback m echanism to inh ibit PTH synth esis. In addition, kidneys serve as th e prim ary route for excretion of waste products including ph osph ate, alum inum , and other toxic agen ts. Th erefore, ch ron ic ren al failure results in a sign ifican t rise in blood urea n itrogen , creatin in e, an d ph osph ate. Th e in jury to ren al tissue creates a reduced tubular m ass, which interrupts 1,25-dihydroxy-vitam in D synthesis. Th is leads to a drop in serum calcium , which causes a m arked increase in serum PTH and resulting secondary hyperparathyroidism . Th e bon e path ology, th erefore, sh ows sign s consisten t with both rickets or osteom alacia and hyperparathyroidism (Fig. 6.8). Th e path ophysiology of ren al osteodystrophy is subdivided in to two groups: high turn over and low turnover. Th e h igh -turn over state is th e classic form of th is disease. Th is form of ren al osteodystrophy is associated with h igh PTH. Serum levels of PTH m ay be 5 to 10 tim es above the upper level of norm al in patients with secondary hyperparathyroidism . In th e presen ce of elevated PTH levels, bon e turn over rem ain s h igh an d th us in creases th e activity of both osteoblasts and osteoclasts. Conversely, the low-turn over state is associated with norm al to low serum PTH. Th e path ogen esis of low-turn over ren al osteodystrophy is com plex an d in cludes a large n um ber of factors such as alum in um -based phosphate binder and peritoneal


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Figure 6.8 The pathophysiology of renal osteodys-

trophy. The skeletal presentation in patients with renal osteodystrophy shows changes consistent with both rickets and osteomalacia and osteitis fibrosa cystica, which is an antiquated term for hyperparathyroidism. (Adapted from Mankin HJ. Metabolic bone disease. In: Jackson DW, ed. Instructional Course Lectures, volume 44. American Academy of Orthopaedic Surgeons, 1995:15.)

dialysis. It is also believed th at ch an ges in a variety of growth factors an d cytokin es could directly impact th e bon e form ation rate.

an d at th e tufts of th e distal ph alan ges (Fig. 6.9). Brown tum or, wh ich is a lytic area with a m arked decrease in cortical structure, can also be foun d (Figs. 6.10 an d 6.11). In som e patien ts, the cancellous bone adjacent to the vertebral

Clinical Presentation Th e clin ical m an ifestation s of ren al osteodystrophy are diverse and nonspecific. Bone pain is usually diffuse and m ay be associated with weigh t-bearing positions. Proxim al m uscle weakness is also relatively com m on. Children with ren al osteodystrophy m ay m an ifest with lin ear growth failure, deform ities of th e lon g bon es, slipped capital fem oral epiphysis, an d fractures. Th e elevation of both serum calcium and phosphate levels leads to extraskeletal calcification. These include periarticular calcification, vascular calcification of m edium and sm all arteries (Monckeberg’s sclerosis), an d calcification of the visceral organs such as lungs, heart, kidn eys, or skeletal m uscle. Som e patients m ay presen t with isch em ic n ecrosis of th e skin (calciphylaxis), wh ich is a rare con dition with catastroph ic con sequen ces.

Radiographic Features Gen erally, th e im agin g studies of patien ts with ren al osteodystrophy sh ow ch an ges con sisten t with both rickets/ osteom alacia an d hyperparathyroidism . In its severe form , hyperparathyroid bon e disease m ay predom in ate an d m anifest as subperiosteal or subchondral erosions. The classic sites of subchondral resorption are at the distal clavicle, sacroiliac joints, and pubic symphysis, while subperiosteal resorption occurs alon g th e m edial border of th e proxim al tibia, th e radial border of th e m iddle ph alan ges,

Figure 6.9 Anteroposterior radiograph of the right and left tibia,

showing subperiosteal resorption at the medial border of the proximal tibia (arrowheads). (Courtesy of Bernard Ghelman, MD.)

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Figure 6.10 Anteroposterior radiograph of the right hip show-

ing a well-demarcated lytic lesion in the proximal femur. The cortices are thin on both sides but remain intact. This localized area of bone destruction is known as brown tumor. Treatment of underlying hyperparathyroidism results in the resolution of these lesions. (Courtesy of Bernard Ghelman, MD.)

en dplates con den ses in to radiopaque ban ds, givin g a distin ct striped appearan ce of altern atin g lucen t an d opaque ban ds kn own as “rugger jersey’’spin e (Fig. 6.12).

Treatment Th e treatm en t of ren al osteodystrophy is depen den t on the renal disease. The goals are to m aintain serum levels of calcium an d ph osph orus as close to n orm al as possible, to avoid alum in um an d iron toxicity, and to preven t th e developm en t of parathyroid hyperplasia or, if secondary hyperparathyroidism has already developed, to reduce th e serum PTH level to acceptable value. Dietary restriction of ph osph orus can h elp in regulatin g serum ph osph ate levels an d th us preven tin g soft-tissue calcification . Active vitam in D sterols (1,25-dihydroxy-vitam in D) are importan t to correct vitam in D deficien cy an d to con trol hyperparathyroidism . Recen tly, a n ew agen t for th e treatm en t of hyperparathyroidism , cin acalcet hydroch loride, wh ich blocks PTH actions, has been introduced and seem s to be extrem ely useful in decreasing the levels of PTH. In situation s wh ere serum PTH rem ain s excessively high, surgical rem oval of parathyroid tissue m ay also be required.

Figure 6.11 Radiograph of the right foot in a patient with hy-

perparathyroid bone disease showing brown tumor of the distal metaphysis of the fifth metatarsal (asterisk), and subperiosteal resorption of the second, third, fourth, and fifth proximal phalanges (arrowheads). (Courtesy of Bernard Ghelman, MD.)

PAGET’S DISEASE Paget’s disease of bone (also known as osteitis deform ans) is a localized disorder of bon e rem odeling. The disease process is initiated by increases in bone resorption, with subsequent compen satory increases in new bone form ation. Because of th e rapid bone turn over rate, th e affected bon e loses its control of the bony structure and thus results in disorgan ized m osaic pattern of woven an d lam ellar bon e. Although m ost patien ts are asymptom atic, those affected with th is disease m ay experien ce a variety of clin ical symptom s an d sign s depen din g on th e severity, n um ber, an d location of the affected skeletal sites. Th e clinical presen tation in cludes bon e pain , secon dary osteoarth ritis, bon e deform ity, an d com plication s from bony com pression to the adjacent soft-tissue structure, such as neural tissue surroundin g th e pagetoid bone.

Epidemiology and Etiology Paget’s disease is the second m ost com m on m etabolic bon e disease after osteoporosis with m ost series describing a slight m ale predom inan ce. The prevalence rate of the disease is dependent on geograph ic area. Am ong all population s, Caucasian s, especially people from En glan d,


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the overall bone turnover is equivalent. The h istopathologic fin din g is depen den t on th e stage of th e disorder to affected bon e. Th e early ph ase is dom in ated by in creased bon e resorption by activated osteoclasts, resultin g in a lytic lesion th at is appreciated radiograph ically as “blade of grass’’ lesion in lon g bone or “osteoporosis circum scripta’’ in skull. Th ese osteoclasts are m ore n um erous an d con tain m ore n uclei th an do n orm al osteoclasts. In order to respon d to th e in creased bon e resorption , osteoblasts are recruited to th e affected area. Durin g th is blastic ph ase, because of the n ature of rapid turnover, the n ewly deposited collagen fibers are laid down in a disorgan ized pattern, creating a m ore prim itive woven bone. Th is results in an irregularity of con tour of th e n ew trabeculae an d cortices. In addition , th e bon e m arrow is in filtrated by th e osteoclasts, osteoblasts, an d blood vessels between th e trabeculae, creatin g th e hypervascular state of th e bon e. Over tim e, the hypervascularity and hypercellularity process extin guish es by itself, leavin g th e en d result of a sclerotic, en larged, m osaic pattern . This is a sclerotic phase or a so-called burn ed out Paget’s disease in wh ich n eith er bon e form ation n or resorption takes place. Gen erally, all ph ases can be seen at th e sam e tim e in differen t areas of the patients with Paget’s disease. Figure 6.12 Anteroposterior radiograph of the lumbosacral

spine demonstrates sharply defined thick bands of sclerosis of both the superior and inferior vertebral endplates, giving a horizontal striped appearance, or so-called rugger jersey (football sweater) spine. (Courtesy of Bernard Ghelman, MD.)

Australia, and New Zealand, h ave m uch higher prevalen ce rates th an th e n ative Am erican s, Scan din avian s, African s, In dian s, or Asian s. Paget’s disease h as been reported at a rate as h igh as 3% to 4% in Australia an d New Zealan d, wh ereas th e prevalen ce rate was approxim ately 0.3% of th e population in Norway an d Sweden . To date, th e etiology of this disorder is still un clear. There are several hypotheses for the pathophysiology of Paget’s disease including genetic predisposition and slow viral in fection. Several studies showed that 15% to 30% of patien ts with Paget’s disease have positive fam ily history of this disorder. Because of th e docum en ted frequen cy of fam ilial h istory with Paget’s disease, th ere is a suggestion th at th is disease is tran sm itted as an autosom al dom inan t trait. The oth er in triguing hypoth esis is a possible relation sh ip between Paget’s disease an d viral infection such as parvomyxoviruses (m easles, m umps, an d parain fluenza). Although som e literature suggests the possibility of an im al-related in fection or ch ron ic in fection from respiratory syncytial virus, the conclusion was not born e out from addition al studies.

Pathology Paget’s disease is a disorder in which bone is synthesized an d degraded at rapid rates but generally equal. Therefore,

Clinical Presentation Paget’s disease is m ost com m on ly diagn osed in in dividuals older than 50. Many patients, th erefore, h ave Paget’s disease for a period of tim e before th e diagn osis is m ade. It m ay presen t as a m on ostotic lesion , wh ich affects on ly on e bon e, a portion of bon e, or a polyostotic lesion , wh ich involves two or m ore bones. The m ost com m on areas of involvem ent include the pelvis, fem ur, spine, skull, and tibia. Upper extrem ities, hand, and feet are less com m only affected. In general, m ost patients with Paget’s disease are asymptom atic an d the diagnosis is m ade when abnorm al blood ch em istry such as an elevated alkalin e ph osph atase is noted or when an inciden tal finding from the radiograph s is foun d. Th e developm en t of symptom s or com plication s of Paget’s disease is in fluen ced by area of in volvem en t, the exten t of m etabolic activity, and th e effect of pagetoid bon e to th e adjacen t structure. Bon e pain, eith er m ild or severe, is probably the m ost com m on sym ptom . Bon e pain m ay be associated with a h igh -turnover state when th ere is hypervascularity at th e area of involvem ent. Bowing deform ity especially of the fem ur and tibia are com m on and can lead to secondary osteoarth ritis from alteration of th e m ech an ical axis an d abn orm al gait pattern . Paget’s disease of th e vertebral bodies can produce sign s an d symptom s sim ilar to spin al sten osis, wh ile Paget’s disease of the skull m ay affect cranial n erves, causin g cranial n erves palsies in cran ial n erves II, VII, VIII. Increased blood supply to the affected bone results in a large am ount of cardiac output and, if prolonged and untreated, m ay impair left heart function and lead to

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high-output left heart failure. Paget’s sarcom a is a rare and devastatin g com plication with an in ciden ce of less th an 1%. Th e m alignant transform ation is typically located in the fem ur, pelvis, hum erus, and skull.

Diagnosis When Paget’s disease is suspected, th e diagnostic evaluation in cludes a th orough m edical h istory, physical exam in ation , laboratory in vestigation s, an d im agin g studies. Patien ts with Paget’s disease usually show elevated serum bon e-specific alkalin e ph osph atase levels, wh ich in dicate in creased osteoblast activity, wh ereas h igh con cen tration of NTx or CTx in th e urin e reflects in creased bon e resorption . Although these findings are n ot specific, the utility of these m arkers is prim arily to assess th e respon se of treatm en t an d to follow th e course of disease over tim e. The findin gs from plain radiograph s include four im portan t fin din gs: (a) th e width an d som etim es len gth of in volved bon e are greater th an n orm al; (b) th e cortices are wider; (c) th e trabeculae in th e m edullary can al are coarse but disorganized; and (d) the m edullary bone often contains lytic areas of various sizes (Fig. 6.13). Gen erally, the characteristic findings from plain radiograph and clinical features of Paget’s disease can elim in ate oth er differen tial diagn oses.

Figure 6.13 Anteroposterior radiograph of the right proximal

femur in a patient with Paget’s disease. Note the increased width of the femoral shaft, markedly thickened cortices, coarse but disorganized trabeculae, and small lytic areas within the medullary canal.

Treatment Patients who are asymptom atic can be treated conservatively by serial follow-up with radiographs, bone scan, an d assays for bone m arkers. There is no clear indication for treating this group of patients. Two logical recom m en dations for treatm en t of Paget’s disease are to relieve sym ptom s an d to prevent future complications. It is still inconclusive whether asymptom atic patients with active disease (elevated alkalin e ph osph atase) sh ould be treated. In th is settin g, m edical treatm en t m ay preven t th e patients from developing later problem s or complications, especially in th e youn ger patien t for wh om m any years of coexisten ce with th e disease is likely. However, th ere is no clinical study to prove that disease suppression reduces th e progression of bon e deform ity. Specific th erapeutic agents available in th e United States for treatm en t of Paget’s disease include bisphosphon ates and calcitonin. Th e action of bisph osph on ates is prin cipally by altering calcium m etabolism and inhibiting osteoclast activity. Currently, four bisphosphonates have been recom m ended as the first- lin e drugs of treatm ent: alendronate, risedron ate, pam idron ate, an d zoledron ic acid. Th e dosage for treatm ent of Paget’s disease, h owever, is higher and m ore frequent than that recom m ended for treatm ent of postm en opausal osteoporosis. Studies showed th at patients treated with intravenous bisphosphonates have a rem ission in their symptom s and a m arked change in their bioch em ical profiles. In addition, bisphosphonate therapy has been sh own to reduce arth ritis difficulty, spinal canal narrowing, h earin g loss, and fracture rates. Calciton in h as been sh own to be effective in Paget’s disease for m ore th an 30 years. However, on ly th e in jectable form ulation is approved by the FDAfor treatm ent of Paget’s disease. Th e improvem en t of clin ical sign s an d sym ptom s is noted in a few weeks, and the reduction of serum alkaline ph osphatase is usually observed after 3 to 6 weeks of treatm ent. The initial starting dose is 100 IU everyday. O nce the patient observes the symptom atic ben efits from m edication , the dose sh ould be reduced to 50 to 100 IU every oth er day. Because n ew gen eration bisph osph on ates offer greater efficacy an d are easier to use, calciton in is n ow reserved for patien ts who cannot tolerate or have contraindications to bisphosphon ate therapy. Patien ts who develop osteoarthritis, fractures, or spinal stenosis m ay n eed to be treated with surgical intervention. However, surgery in these patients m ay be complicated by excessive blood loss, h igh -output cardiac failure, h eterotopic bon e form ation , or loosen in g of th e implan t. Th erefore, patients need careful attention durin g the pre- and postoperative period. It is recom m en ded to give bisph osph on ates before an elective surgery. Th e goal is to reduce hypervascularity associated with active disease, wh ich will reduce th e am oun t of blood loss an d poten tial complication from left heart failure.


SUMMARY Metabolic bone diseases are a group of disorders that occur as a result of changes in osteoblast an d osteoclast fun ction. Th e osteoblast an d osteoclast play a m ajor role to m ain tain structural and m aterial properties of bon e, control the syn thesis of bone m atrix, and regulate m ineral m etabolism as well as th e m in eralization process. Th us, an alteration of these cell function s results in a variety of clinical disorders. An understandin g of the pathogenesis of such diseases and an attempt to define the cause of the patien t’s acute problem is the key for treatm ent. Th is requires a thorough m edical history, physical exam in ation, im aging studies, and appropriate laboratory in vestigation s. Orth opaedic surgeon s sh ould be aware of these biologic and biochem ical disor-

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ders an d fam iliar with th eir clin ical presen tation . Th e ultim ate success in treatm en t of th e orth opedic m an ifestation s of th ese disorders often n ecessitates direct correction of th e un derlyin g disease process.

RECOMMEND READINGS Holick MF. Vitam in D deficien cy. N Engl J Med. 2007;357(3):266 –281. Lin JT, Lan e JM. Osteoporosis: a review. Clin Orthop Relat Res. 2004; (425):126 –134. Mankin HJ, Mankin CJ. Metabolic bone disease: an update. In: Ferlic DC, ed. Instructional Course Lectures. Rosem ont, IL: Am erican Academy of Orthopaedic Surgeon s, 2003:769. Regin ato AJ, Coquia JA. Musculoskeletal m an ifestation s of osteom alacia and rickets. Best Pract Res Clin Rheumatol. 2003;17(6):1063 – 1080. Siris ES, Jacobs TP, Can field RE. Paget’s disease of bon e. Bull N YAcad Med. 1980;56(3):285 –304.

Rheum atology and Im m unology for the Non-Rheum atologist Dan iel J. Clauw

7

Jacob N. Ablin

THE IMMUNE SYSTEM Overview Th e im m un e system serves m any vital fun ction s, in cludin g defen se again st foreign organ ism s an d surveillan ce again st tum ors. But function, or dysfunction, of th e im m une system also plays a sign ifican t role in m any rh eum atic diseases. In som e cases, th e dam age caused by th e im m un e system is an inevitable con sequen ce of killing in vading m icroorgan ism s (e.g., polym orph on uclear [PMN] cells attacking bacteria in a septic join t). In oth er in stan ces, hyperactivity of th e im m un e system is th e prim ary problem , as occurs in autoim m un e disorders where “self’’antigens are recognized as foreign, such as rheum atoid arthritis (RA) or system ic lupus erythem atosus (SLE). In yet other settings, an initial injury can be followed by an inflam m atory response that is responsible for continued symptom s (e.g., tendin itis or bursitis). Th us, to un derstan d th e diagn osis an d m an agem en t of rh eum atic disorders, it is crucial to un derstan d th e basic organ ization of th e im m un e system . Th e focus of th is review is to introduce th e basic concepts of im m un ology and im m unopathology as they relate to rheum atic disorders. As with any attempt to m ake an extrem ely complex system simple, importan t details are n ecessarily om itted, an d the reader is en couraged to con sult m ore detailed reviews of these subjects for th is in form ation. Th e im m un e respon se can be divided in to two broad categories: specific an d n on specific. Th e n on specific im m un e

respon se in cludes m ucosal barriers of defen se, som e types of im m un e cells, an d th e altern ative path way of com plem en t activation . Th e specific im m un e respon se in volves a soph isticated afferent system to recognize self from nonself. After th e im m un e system has distin guish ed self from n on -self, th ere is a set of specific effector agen ts that acts to target an d destroy extern al agen ts, h opefully with th e least dam age possible to h ost tissues. Defects in th e fun ction of th is system lead to m ost of th e classic autoim m un e disorders.

Components of the Immune System General Concepts Durin g fetal developm en t, h em atopoietic cells m ove from th e yolk sac to th e bon e m arrow an d oth er tissues to begin differentiating into lymphoid and myeloid cell lines. Myeloid cells are widely distributed in m any tissues, wh ereas lymph oid cell lin es con cen trate in h em atopoietic organ s such as th e thym us, spleen , lymph n odes, an d bon e m arrow. The developm ent of lymphoid cells is particularly com plex. Alth ough all lym ph oid cells are produced in th e bon e m arrow, on e type of cell lin e m igrates to th e thym us (the “T’’ cell) for further developm en t. The thym us plays a crucial role, bein g particularly importan t for th e developm en t of th e ability to recogn ize self from n on -self (tolerance) by these cell lin es. Mature T lymphocytes then direct th e im m un e role of self-recogn ition an d regulate both cell- an d an tibody-m ediated (h um oral) im m un ity.

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Durin g early developm en t, cells th at will even tually becom e B cells (a n am e derived from the in volvem en t of a bursa in th is process in birds) m ature in depen den t of th e thym us. These cells develop cell surface m arkers such as surface im m unoglobulin s (Igs), an d their m ajor fun ction is to produce an tibodies. An important concept for understandin g th e function of both Tan d Bcells is th e process of clon al expan sion . In early developm en t, th e im m un e system h as cells th at could th eoretically respon d to virtually any possible an tigen . Th e subsequen t interaction of th e in dividual with the en viron m ent will largely determ ine which of these cell lin es are stim ulated to expan d an d replicate (i.e., clon al expan sion ) an d which are deleted (because they react with self-antigen s). Th is latter con cept th at describes th e loss of reactivity to self-antigens is term ed immune tolerance. Another basic distinction important for un derstanding the way in which the im m une system function s in sickness an d in h ealth is th at between th e in n ate an d th e adaptive im m un e respon se. Th e in n ate im m un e respon se is a phylogen etically m ore an cien t system design ed prim arily for com bating infectious agents. This response is ch aracterized by n ot bein g depen den t on previous exposure to an tigen to respon d. Th ese cells recogn ize fixed path ogen associated m olecular pattern s. Th is rapid respon se m ech an ism is, h owever, lim ited in its ability to react to n ovel threats. The adaptive im m un e system , on the other han d, functions through selection and m utation of the im m une cells to m ount a h ighly targeted response to a previously en coun tered an tigen .

Antigen-Presenting Cells Th is class of cells h as m any roles both in th e in n ate an d the adaptive im m une respon se. In th e latter, the first step is th e in teraction between an tigen an d an tigen -presen tin g cells (APCs). There are a num ber of cell types that are capable of actin g as APCs, in cludin g B cells, tissue m acroph ages, an d site-specific cells such as den dritic cells in th e skin or Kupffer cells in the liver. In general, th ese cells first “process’’antigen by intern alizin g protein and digesting the protein in to peptides, an d th en “presen t’’th ese peptides on th e cell surface for recognition by another class of lymphocytes known as T cells, through an interaction with specific T cell receptors (TCRs). T Cells T cells (particularly th e CD4+ subset of T cells, also called helper T cells) are respon sible for th e recogn ition of an tigen s on APC cells in a T-cell–depen den t an tibody respon se. When th e im m un e system is fun ctioning properly, T cells will respond to foreign antigens but n ot to self-antigen s. Th is process occurs prim arily in th e thym us an d in volves the positive selection of clones of cells that respon d to foreign an tigen s an d th e elim in ation of clon es th at respon d to self-an tigen s. In addition , rapid cell death (apoptosis) of activated T cells m ust occur at th e term in ation of th e

im m une response to prevent undue accum ulation of h azardous im m un e cells. Wh en a CD4+ T cell binds to an antigen on an APC, several processes occur. Th e T cell becom es “activated’’and expresses a differen t set of cell surface receptors an d subsequen tly produces a num ber of soluble m olecules (cytokines) th at can cause both local an d distant effects on im m une and nonim m un e fun ctions. A prom inent fun ction of these cytokin es is to attract new m acrophages to the tissue. These new m acrophages that were n ot involved in th e in itial an tigen presen tation are m ore effective at ph agocytosis an d m icroorgan ism killin g. Th e oth er m ajor class of T cells is th e CD8+ (T suppressor) cell. T suppressor cells have quite different functions th an th eir CD4+ coun terparts, h avin g n o role in th e h um oral antibody process but instead being responsible for T-cell killin g. Th is m ech an ism of direct cell killin g is particularly importan t in defense again st viruses an d intracellular organ ism s. Cytotoxic T cells can kill infected cells by th e excretion of perforin , a protein capable of drillin g h oles in the cell m em brane, or by ligands that activate death receptors such as Fas or tum or n ecrosis factor-alph a (TNF-α) receptor. Th ese cells h ave specificity for an tigen s associated with th e m ajor h istocompatibility complex (MHC) class I products, th e HLA-A, B, an d C an tigen s, in con trast to th e class II product specificity of CD4+ cells (Fig. 7.1). In addition , th e CD4+ an d CD8+ cells play an essen tial role in regulatin g th e overall fun ction of th e im m un e system . Im m un oregulatory cytokin es in cludin g in terleukin s (ILs) 2, 4, 5, 7, 9, 10, 11 and gam m a interferon (IFN) are released by T-lymphocyte subsets and exert both positive an d n egative effects on th e overall activity of th e in flam m atory respon se. With in th e classic autoim m un e disorders, som e are characterized by a relative excess of activity of CD4+ cells A MHC class I Pathway

B MHC class II Pathway

Calreticulin

Peptide-MHC Complex

Peptide-MHC Complex CLIP Secretory Vesicle Tapasin

Endosome

HLADM

TAP Complex ER

Peptide Proteosome

ER

MIIC

Figure 7.1 Antigen processing by mononuclear phagocytes.

(A) Major histocompatibility complex (MHC) class I pathway. (B) MHC class II pathway. (Reprinted with permission from Koopman WJ, Moreland LW. Arthritis and Allied Conditions: A Textbook of Rheumatology. 15th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)

Chapter 7: Rheumatology and Immunology for the Non-Rheumatologist

(e.g., SLE, RA), wh ereas others (e.g., ankylosing spon dylitis, reactive arth ritis) are characterized by a relative CD8+ excess. Th is run s in parallel to our un derstan din g of th e im m unogenetic risk factors for these types of disorders. For exam ple, th e seron egative spon dyloarth ropath ies (SSs) (e.g., ankylosing spon dylitis) are stron gly associated with the presence of the HLA-B27 (or related haplotypes, e.g., B7, Bw22, B42) haplotypes, and CD8+ cells have specificity for these MHC I products. In contrast, the im m unogenetic risk for developin g disorders such as SLE or RA is con ferred by certain MHC class II h aplotypes (e.g., HLA DR4), again in parallel with the m ore prom inent role of CD4+ cells in the pathogenesis of these disorders. This phenom enon of reciprocal roles of CD4 an d CD8 cells also appears to be eviden t wh en person s with autoim m un e disorders becom e infected with the hum an im m unodeficiency virus (HIV). The lowering of the CD4+ count associated with this disease frequently leads to an improvem en t in CD4+ – depen den t disorders such as SE or RA but a m arked worsen in g of CD8+ –depen den t disorders such as th e SSs. Differen t types of an tigen s also elicit differen t types of im m un ologic responses. For example, som e antigens, such as mycobacterium an d fun gi, elicit exclusively a cell-m ediated respon se, wh ereas m ost path ogen s elicit a m ixed respon se.

B Cells Once activated, the m ajor function of the B cell is to produce an tibodies. Th is activation can occur via a T-cell– depen den t or a T-cell–independent m echanism . In the T-cell–depen den t system , th e CD4+ cell is activated via an interaction with a specific APC. Som e antigens are capable of directly in teractin g with B cells, in depen den t of T cells, and lead to a less-specific Ig response. A sm all proportion of B cells will develop in to long-lived

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m em ory cells, retain in g th e in form ation an d th e capacity to respon d rapidly upon reexposure to a previously en coun tered an tigen . After such reexposure, such cells can develop in to plasm a cells—large, term in ally differen tiated cells th at h ave th e capacity to specifically produce large am ounts of an tibody.

Immunoglobulins Igs are th e product of activated m ature Bcells. Th ere are n in e classes of Igs, each of wh ich con sists of two h eavy ch ain s and two light chains. For each type of Ig, th ere is a constant region th at is largely respon sible for th e physiologic fun ctions of the Ig m olecule (e.g., complem ent activation) and a variable dom ain th at is largely respon sible for th e an tigen specificity of th at particular Ig. Each of the subclasses of Ig serves different function s (Table 7.1). Autoantibodies are Igs directed against self-antigens. The two m ost com m only considered autoantibodies are antinuclear an tibodies (ANAs) an d rh eum atoid factor (RF). ANAs are antibodies directed again st various componen ts of the cell n ucleus. Th ese an tibodies are a serological h allm ark of autoim m une disease such as SLE, in which they are present in 99% to 100% of patients. Several factors need, however, to be con sidered before ordering th is test. First, a substantial percen tage of th e general population (as high as 30%) will h ave a “positive’’result for th is assay usin g n ewer, m ore sensitive tech niques. Because of the low specificity of this test, it sh ould be ordered on ly wh en th ere is a h igh pretest probability th at th e person h as a disease ch aracterized by a positive ANA. If th is test is foun d to be positive, th en furth er testin g for extractable n uclear an tigen s can be con sidered (e.g., an ti-Ro [SSA], an ti-La [SSB], an ti-Sm , an ti-RNP, anti-dsDNA) since th ese are m uch less com m only present as false-positive tests in norm al individuals.

TABLE 7.1

SELECTED BIOLOGIC PROPERTIES OF CLASSES AND SUBCLASSES OF IMMUNOGLOBULINS IgG Percentage of total (%) Complement fixation Complement fixation (alternative) Placental passage Fixing to mast cells or basophils Binding to Macrophages Neutrophils Platelets Lymphocytes Reaction with Staphylococcus A Half-life (days) Synthesis mg/kg/day

IgA

1

2

3

4

1

2

65 ++

20 +

+ −

+ −

10 ++ + + −

5 − + + −

90 − + /− − −

10 − + /− − −

+ + + + + 23 25

± + + + + 23 ?

+ + + + − 8–9 3.5

± + + + + 23 ?

− + − − − 6 24

− + − − − 6 ?

+ , Positive; + + , Highly positive; − , Negative; ± , Equevical.

IgM

IgD

IgE

++

−

−

− −

− −

− +

− − − + − 5 7

− − − − − 3 0.4

− − − − − 2.5 0.02

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RFs represen t a h eterogen eous group of an tibodies directed again st th e Fc portion of IgG. As with ANA, th is test sh ould be ordered only in persons with a high pretest probability of RA, since wh ile approxim ately 80% of person s with RA will h ave a positive value, RF will also be presen t in som e norm al individuals and in a proportion of patients with a variety of oth er disorders, in cludin g viral an d bacterial in fection s, oth er rh eum atic diseases, an d lym ph oproliferative diseases. Alth ough th e rate of false positive RF is lower for RF th an for ANA, ordering this test in persons with out evidence of syn ovitis or elevated inflam m atory in dices will lead to far m ore false positives th an true positives. Antibodies directed against cyclic citrullinated peptides (anti-CCPs) h ave been found in serum of m any RA patients; a specificity rate as h igh as 98% h as been reported for this an tibody. However, it is importan t to recogn ize th at the serum levels of RF, anti-CCPs, and ANA do not correlate with the level of disease activity, so th at once th ese tests are ordered an d known to be positive, there is little value of followin g these values longitudinally in an individual patien t.

PMN Leukocytes: Neutrophils Th e cells m ost active in th e in itial stages of an in flam m atory respon se are n eutroph ils. Neutroph ils m ay be attracted to th e site of in flam m ation by m any factors, in cludin g proin flam m atory cytokin es (e.g., TNF-α, IL-1, IL-6, IL-8) released by m on on uclear im m un e cells, im m un e complexes, an d compon en ts of th e complem en t cascade. Once present, a neutrophil will attempt to phagocytose individual particles or m icroorganism s by internalizin g an d th en digestin g th e foreign m aterial. Altern atively, in som e settin gs, th e n eutroph ils degran ulate an d release the contents of th eir lysosom al enzym es such as m atrix m etalloprotein ases (MMPs), elastase, an d lysozym e in to the tissue environm ent, a process that can be responsible for extensive tissue dam age. A related toxic effect of neutroph ils, both to m icroorgan ism s an d tissues in volved in in flam m ation , is th e release of oxygen free radicals. After activation , n eutroph ils rapidly un dergo program m ed cell death (apoptosis), wh ich is critical for con trollin g th e in flam m atory response. Eosinophils are a specialized class of PMN cells m ain ly found within tissue. These cells are m ainly activated by IgA an d IgE an tibodies an d play an importan t role in th e body’s defen se again st h elm in th ic an d parasitic in fection s, on th e on e h an d, an d in atopic an d allergic reaction s on th e oth er hand. Monocyte/Macrophages Mon ocytes are circulatin g un stim ulated m acroph ages. In addition to th e previously described role of th ese cells as APCs, m acrophages also play a vital role in control of the in flam m atory respon se. It h as been estim ated th at th ere

are m ore than 100 products produced and released by m acrophages, including cytokines, complem en t compon en ts, coagulation factors, an d bioactive lipids such as cyclooxygen ase an d lipoxygen ase products. Th ese cells are typically attracted to sites of in flam m ation through the activity of chem oattractant m olecules (chem okines) and carry specific m em brane receptors for th ese sign als. Mon ocytes an d m acroph ages also carry m ultiple receptors for componen ts of the complem ent system . Th ese cells appear to participate in m any addition al roles besides com batin g in fectious agen ts. For example, scavenger m acroph ages participate in uptake of cholesterol particles com batin g developm en t of ath erosclerotic plaque wh ile uptake an d clearan ce of apoptotic cells in th e circulation by m acrophages is a hom eostatic function, which prevents the developm ent of autoim m une reactions to these dyin g cells.

Complement Th e complem en t system con sists of a series of protein s th at are in volved in m ediating a variety of inflam m atory effects. As with other compon ents of the im m un e system , this system is vital in protectin g th e organ ism s again st in fection (particularly bacterial pathogens) but can be respon sible for tissue dam age in rheum atic disorders. Th ree separate path ways of complem en t activation h ave been iden tified: th e classical path way, th e altern ative path way, and the lectin pathway (LP) (Fig. 7.2). Although these

Figure 7.2 Complement activation pathways. (Reprinted with permission from Koopman WJ, Moreland LW. Arthritis and Allied Conditions: A Textbook of Rheumatology. 15th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)


path ways are activated in differen t m an n ers, th e term in al even t in all sequen ces is th e cleavage of C3 to C3a an d C3b. Activation of the complem ent system is closely regulated by inh ibitory en zym es such as C1 in hibitor, which act to preven t excessive and dangerous activation of the complem ent cascade. A num ber of components of the complem ent cascade are responsible for the biological consequences of activation. C3a an d several other products of the classical com plem en t cascade act as an aphylatoxin s. Th ese substan ces lead to m ast cell and basophil degranulation, releasing a variety of m ediators responsible for sm ooth m uscle contraction, local edem a, and increased vascular perm eability. C3b begins a series of steps leading to the form ation of m em brane attack complex (MAC) th at is capable of leading to dam age or death of a num ber of different cell types via insertion into th e cell m em brane. In addition to being a m ajor part of the innate im m une response, the complem en t system also participates in adaptive (hum oral) im m un ity. Thus, IgM and IgG activate complem ent, leading to opson ization an d lysis of cells. Complem en t also plays an importan t role in apoptotic cells uptake and clearan ce. Hom ozygous deficien cies of com plem en t m ay lead either to an increased incidence of infection (especially of organ ism s such as Neisseria that are killed by MAC) or to autoim m un e disorders. Th e paradoxical developm en t of autoim m un e disorders in in dividuals with h ereditary complem ent deficiencies h as been perplexing since m any autoim m un e diseases are ch aracterized by complem ent con sumption. The best supported theory for this ph enom en on is that com plem ent is vital for norm al clearance of im m un e complexes in th e circulation an d th at th ese deficien cy states are ch aracterized by in effective im m un e complex clearance an d subsequent complem ent activation . Patients deficien t in specific components of the complem en t classical pathway m ay suffer from an extrem ely h igh prevalen ce of SLE (up to 90% in C1q deficien cy). Complem en t m easurem en ts can som etim es be useful in assessin g an individual for the presence of, or activity of, an autoim m un e disorder. Th e CH50 is an assay of total hem olytic complem ent activity an d is a useful screen in g test if a hom ozygous complem ent deficiency is suspected. Assays for in dividual complem ent levels (C3 and C4 are th e m ost available com m ercially) can som etim es be helpful to assess for activity of autoim m un e disorders ch aracterized by complem ent consumption (e.g., im m une complexm ediated disorders such as SLE, RA, cryoglobulin em ia). However, in m any in stances, th ese values are difficult to interpret sin ce complem ent is produced in increased quan tities by the liver as an acute phase reactan t. Thus, in m any autoim m un e disorders characterized by complem ent consumption , a n orm al plasm a value can still occur because of increased liver synthesis. Measurem en t of complem ent activation fragm ents (such as C3a and C5a) m ay be m ore specific, not being influenced by in herited deficien cies. However, th ese tests are m ore costly an d less frequen tly available in clinical use.

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Immunoregulation and Immunopathology Im m un oregulation in volves a ten uous balan ce of reactin g to pathogens with out h arm ing the h ost. There are several levels of im m unoregulation , beginning in early developm ent with establishm en t of tolerance. Once the organism can appropriately iden tify self-an tigen s, th e respon se to th ese ch allen ges m ust be appropriate to th e poten tial dan ger of th e ch allen ge. An in flam m atory respon se th at is n ot localized to the area of infection, or that persists after th e infection has been cleared, will cause undue dam age to the organ ism . Classically, four types of specific im m un opathologic m echan ism s have been iden tified:

Type I IgE Mediated Th e com bin ation of an IgE an tibody bin din g to th e Fc receptor of a basoph il or m ast cell an d an an tigen bin din g to that antibody leads to stim ulation of these cells. Products con tain ed in basoph ilic gran ules in clude h istam in e, seroton in , bradykin ins, and other substances. This type of reaction is m ost prom in en t in allergic diseases.

Type II Direct Antibody-Mediated Effects on Cells Autoan tibodies bin din g to self-an tigen s on a cell or tissue can cause complem ent fixation an d/or direct cytotoxic killing of that particular cell. An example occurs in som e types of hem olytic anem ia, wh ere red blood cells (RBCs) are destroyed when autoantibodies bind to cell surface antigen s. Th is type of reaction is relatively un com m on . Type III Immune Complex Formation In con trast to type II reaction s, wh ere an tibody bin ds to antigens on a cell or tissue surfaces, in this instance, soluble an tigen s bin d to an tibodies in th e circulation . Th ese im m une complexes m ay bin d to cell surface receptors or activate complem en t and cause an in flam m atory process in the tissue(s) where they are deposited. Many classic system ic autoim m une disorders, such as SLE, are characterized by th e presen ce of circulatin g an d tissue im m un e com plexes. However, it rem ain s un clear how m uch of the disease process is actually caused by th ese im m un e complexes. Type IV Direct Cell Injury Several types of im m un e cells, including both T cells and CD8+ cells, can cause direct cell injury, whereas other types of cells such as CD4+ cells can affect cell in jury by attracting other types of cells. This m echanism is probably operative in a n um ber of autoim m un e an d oth er rh eum atic disorders.

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EVALUATION OF THE PATIENT WITH ARTHRITIS History Th e importan t elem en ts of th e h istory in th e patien t with suspected arthritis are the sam e as for other orth opaedic problem s, alth ough th ere is m ore of an emph asis on certain features. Th ese include elucidating the pattern and tim ing of join t in volvem en t, differen tiatin g in flam m atory from noninflam m atory processes, and determ ining wheth er extraarticular sym ptom s are presen t or absen t. The pattern of involvem ent can be particularly h elpful when evaluating the patien t with arthritis. Examples of such pattern s are wh eth er th e arth ritis is m on oarticular or polyarticular (Tables 7.2 an d 7.3). Alth ough th is distin ction is rarely absolute, as with any clin ical pearl, it can be helpful. Another critical poin t in the evaluation of the patien t with joint pain is h ow the sym ptom s began. Extrem ely rapid onset of symptom s (e.g., over seconds), especially if accompan ied by traum a, suggests a m ech an ical process (e.g., fracture, loose body). Acute on set of symptom s over hours or days m ay occur in a num ber of types of arth ritis an d is especially com m on in in flam m atory arth ropath ies

(e.g., infectious, crystal-induced). The on set of symptom s is less helpful if the process is ch ron ic or evolves over days to weeks, since th is can occur with m any differen t form s of arth ritis. Both th e h istory and physical exam in ation are helpful in differentiating whether the patient is suffering from an inflam m atory or n oninflam m atory arthritis. Elem en ts of th e h istory th at suggest an in flam m atory process in clude prom in en t m orn in g stiffn ess; improvem en t with exercise or activity (or worsen in g by prolon ged im m obility); or a h istory of warm th , redness, or swellin g of th e affected region(s). Pain that is worse after exercise or activity, on the oth er h an d, is suggestive of a n on in flam m atory arth ritis. Th e presen ce or absen ce of n on articular features can also be h elpful in diagn osin g th e patien t with arth ritis. Non articular features are com m only seen in a num ber of condition s, especially system ic autoim m un e disorders, wh ere th e join t is but on e tissue th at is bein g targeted by th e in flam m atory process. Although the patient who presen ts with the complain t of join t pain m ay in deed h ave a process localized to th e join t, it is equally im portan t to recogn ize th e pleth ora of periarticular or n on articular syn drom es th at frequen tly m ay presen t in th is m an n er, such as fibrom yalgia, ten din itis, bursitis.

TABLE 7.2

DIFFERENTIAL DIAGNOSIS OF INFLAMMATORY MONOARTHRITIS A. Crystal-induced 1. Gout—male, lower extremity, previous attack, nocturnal onset, precipitated by medical illness or surgical procedures, response to colchicine, hyperuricemia, sodium urate crystals in joint fluid with neutrophils predominating, and WBC count 10,000–60,000/mm3 2. Pseudogout—elderly patient, knee or other large joint, previous attack, precipitated by medical illness or surgical procedure, flexion contractures, chondrocalcinosis on radiography, calcium pyrophosphate dihydrate crystals in joint fluid with neutrophils predominating, and WBC count 5,000–60,000/mm3 3. Calcific tendinitis, bursitis, or periarthritis—extraarticular, tendon or capsule of larger joints, previous attack in same or other area, calcification on radiography, chalky or milky material aspirated from area, neutrophils with phagocytosed ovoid bodies microscopically B. Palindromic rheumatism Middle-aged or elderly male, sudden onset, little systemic reaction, previous attacks, may be positive rheumatoid factor, little or no residual chronic joint inflammation, residual olecranon bursal enlargement, joint fluid rarely obtained, fibrin deposition on biopsy C. Infectious arthritis 1. Septic—severe inflammation, primary septic focus, drug or alcohol abuse, joint fluid with neutrophils predominating, WBC count 50,000–300,000/mm3 (pus), infectious agents identified on smear and culture, or bacterial antigens identified in joint fluid 2. Tubercular—primary focus elsewhere, drug or alcohol abuse, marked joint swelling for long period, joint fluid with neutrophils predominating, acid-fast organisms on smear and culture 3. Fungal—similar to tuberculosis 4. Viral—antecedent or concomitant systemic viral illness, joint fluid can be of inflammatory or noninflammatory type, either mononuclear cells or neutrophils may predominate D. Other 1. Tendinitis—as in A.3, but without radiologic calcification, antecedent trauma including repetitive motion 2. Bursitis—as mentioned earlier, but inflamed area is more diffuse, antecedent trauma 3. Juvenile rheumatoid arthritis—one or both knees swollen in preteen or teenager without systemic reaction, no erosions, mildly inflammatory joint fluid with some neutrophils, and no depression in synovial fluid C’H50 levels. WBC, white blood cell. (Reprinted with permission from Koopman WJ, Moreland LW. Arthritis and Allied Conditions: A Textbook of Rheumatology. 15th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)


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TABLE 7.3

DIFFERENTIAL DIAGNOSIS OF INFLAMMATORY POLYARTHRITIS A. RA 1. Seropositive—female patient, symmetric joint and tendon involvement, synovial thickening, joint inflammation “in phase,” nodules, weakness, systemic reaction, erosions on radiogram, rheumatoid factor present, C’H50 level depressed in joint fluid that has 5,000–30,000 WBC/mm3 and approximately 50%–80% neutrophils, possible occurrence in children 2. Seronegative—either sex, symmetric joint and tendon involvement, joint inflammation “in phase,” more bony reaction radiographically (sclerosis, osteophytes, fusion, periostitis), rheumatoid factor absent, C’H50 not depressed in joint fluid that has 3,000–20,000 WBC/mm3 and approximately 20%–60% neutrophils, more asymmetric than in seropositive cases, some cases probably are adult juvenile RA B. Collagen vascular disease 1. Systemic lupus erythematosus—female patient, symmetric joint distribution identical to RA, hair loss, mucosal lesions, rash, systemic reaction, visceral organ or brain involvement, leukopenia, positive STS, no erosions radiographically, noninflammatory joint fluid with good viscosity and mucin clot and 1,000–2,000 WBC/mm3 , mostly small lymphocytes, serum C’H50 often depressed, ANA titer elevated, antinative human DNA antibody titer increased, anti-SM antibody increased, anti-SSA (Ro) subset (subacute cutaneous lupus) 2. Scleroderma—tight skin; Raynaud phenomenon; resorption of digits; dysphagia; constipation; lung, heart, or kidney involvement; symmetric tendon contractures; little or no synovial thickening; radiographic calcinosis circumscripta; positive ANA with speckled or nucleolar pattern; anti-SCL-70 (systemic); and anticentromere antibodies (CREST syndrome) 3. Polymyositis (dermatomyositis)—proximal muscle weakness in pelvic and pectoral girdles, tender muscles, rash, typical nailbed and knuckle pad erythema, symmetric joint involvement, EMG showing combined myopathic and denervation pattern, muscle biopsy abnormal, elevated serum creatinine phosphokinase level 4. Mixed connective tissue disease—swollen hands, Raynaud phenomenon, tight skin, symmetric joint and tendon involvement, possible evidence of joint erosions radiographically, positive ANA speckled pattern, anti-RNP antibody increased, strong response to corticosteroid therapy in anti-inflammatory doses 5. Polyarteritis nodosa—symmetric involvement, diverse clinical picture of systemic disease, histologic or angiographic diagnosis C. Rheumatic fever Young (2–40 years of age), sore throat, group A streptococci, migratory arthritis, rash, pancarditis or pericardial involvement, elevated ASO titers, joint inflammation responds dramatically to aspirin treatment, often no cardiac findings in adults D. Juvenile RA Symmetric joint involvement, rash, fever, absence or rheumatoid factor, radiographic periostitis, erosions late, possibly beginning or recurring in an adult, ANA-positive pauciarticular girls may develop iridocyclitis, B27-positive boys with possible fusion of sacroiliac and spinal joints E. Psoriatic arthritis Asymmetric boggy joint and tendon swelling, skin or nail lesions not always prominent or may follow arthritis, DIP joints may be prominently involved, radiologic periostitis or erosions, no rheumatoid factor, C’H50 level usually not depressed in inflammatory joint fluid with neutrophilic predominance F. Reactive arthritis Male patient, homosexual and/or sexually promiscuous, urethritis, iritis, conjunctivitis, asymmetric joints, lower extremity, nonpainful mucous membrane ulcerative lesion, balanitis circinata, keratoderma blennorrhagica, weight loss, C’H50 increased in serum and in joint fluid with 5,000–30,000 WBC/mm3 , macrophages in joint fluid with three to five phagocytosed neutrophils (“Reiter” cell), possible sequela of enteric infections or urethritis, syndrome may be incomplete and may affect females G. Gonorrheal arthritis Migratory arthritis or tenosynovitis finally settling in one or more joints or tendons, either sex, primary focus urethra, female genitourinary tract, rectum, or oropharynx, skin lesions, vesicles, gram-negative diplococci on smear but not on culture of vesicular fluid, positive culture at primary site, blood, or joint fluid H. Polymyalgia rheumatica Elderly patient (> 50 years), symmetric pelvic or pectoral girdle complaints without loss of strength, morning stiffness of long duration, prominent fatigue, weight loss, possible joint involvement, especially of shoulders, sternoclavicular joint, knees, sedimentation rate elevated, fibrinogen and [- and T-globulin elevation, anemia, complete response to low doses (10–20 mg) prednisone, serum CPK level normal, elevated alkaline phosphatase (liver) level I. Crystal-induced 1. MSU crystals (gout)—symmetric arthritis, flexion contractures, history of acute attacks, tophi, out-of-phase joint inflammation, systemic corticosteroid treatment for RA, hyperuricemia, MSU crystals in joint fluid 2. CPPD crystals (pseudogout)—symmetric arthritis, MCP flexion contractures, as well as of wrist, elbow, shoulder, hip, knees, and ankles, prior acute attacks (sometimes), out-of-phase joint inflammation, CPPD crystals in joint fluid 3. BCP crystals (Milwaukee shoulder) J. Other amyloid arthropathy, peripheral arthritis of inflammatory bowel disease, tuberculosis, SBE, viral or spirochetal arthritis ANA, antinuclear antibody; ASO, antistreptolysin O; BCP, basic calcium phosphate; CPK, creatinine phosphokinase; CPPD, calcium pyrophosphate dihydrate disease; CREST syndrome, calcinosis, Raynaud phenomenon, esophageal involvement, sclerodactyly, and telangiectasia; DIP, dorsal interphalangeal; EMG, electromyography; MCP, metacarpophalangeal; MSU, monosodium urate; RA, rheumatoid arthritis; RNP, ribonucleoprotein; SBE, subacute bacterial endocarditis; STS, serologic tests for syphilis; WBC, white blood cell. (Reprinted with permission from Koopman WJ, Moreland LW. Arthritis and Allied Conditions: A Textbook of Rheumatology. 15th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)

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Physical Examination Both a general physical exam in ation and a m usculoskeletal exam in ation are im portan t in th e patien t wh o presen ts with arth ritis. As n oted earlier, th ere are a pleth ora of n on articular features th at can accom pany arth ritis. In the m usculoskeletal exam ination, the goal of th e evaluation is to (1) determ in e th e exten t of in volvem en t, (2) localize th e an atom ic structure(s) in volved, an d (3) determ in e wh eth er th e process is in flam m atory or n on in flam m atory. To determ in e th e exten t of in volvem en t, it is im portan t to perform a gen eralized exam in ation of th e join ts an d soft tissues, even if th e patien t presen ts with a localized complain t. Th e patien t with a system ic in flam m atory process will very frequen tly presen t with th e complain t of pain in a sin gle join t. Lim itin g th e focus to th at join t will lead to an improper diagn osis an d in effective treatm en t. The best m anner to localize the anatom ic structure(s) in volved is to perform th e m usculoskeletal exam in ation by palpatin g with firm pressure (enough to blanch th e exam in er’s fin gern ail) over both join ts an d soft tissues, first in region s of th e body wh ere th e person is n ot complain in g of pain and finally in the affected region. This type of exam in ation accom plish es several objectives. On e is to assess th e patien ts’ overall pain th resh old. If in dividuals have tendern ess over bones and soft tissues in a n um ber of region s in th e body, th ey m ay suffer from a gen eralized disturban ce in pain processin g (e.g., fibrom yalgia) rath er than a process localized to a specific region. This type of exam in ation also will detect wh eth er periarticular structures (e.g., tendon in sertion s, bursae) are in volved. Secon d, th is procedure iden tifies in dividuals wh o m ay h ave m ore th an on e process th at is coexpressed an d respon sible for sym ptom s (e.g., th e patien t with osteoarth ritis [OA] of th e h ip or kn ee an d con curren t troch an teric or an serin e bursitis in volvin g th ose sam e region s, respectively). Using the above-m ention ed technique, special attention is paid to th e join ts, an d in particular, exam in in g th e join t for evidence of synovitis. To the unskilled exam in er, an en larged join t represen ts “arth ritis.’’ But with experien ce, palpation of en larged join ts can differen tiate th e firm an d less pain ful bony proliferation secon dary to osteophytes (as occurs with Heberden an d Bouch ard n odes in th e distal in terph alan geal [DIP] an d proxim al in terph alan geal [PIP] join ts of th e h an ds in OA) from th e ten der, “boggy’’swellin g seen in ch ronic in flam m atory arthritis due to synovial proliferation an d/ or join t effusion s.

Diagnostic Testing Again , the evaluation of the patient with arth ritis parallels th at of th e patien t with oth er orth opaedic problem s, alth ough certain poin ts bear emph asis. Perh aps, th e m ost importan t poin t to emph asize is th at th e h istory an d physical exam ination typically yield far m ore useful inform ation than do laboratory studies. This can be stated in two differ-

en t ways: (1) if you do n ot h ave a good idea of th e correct diagn osis before orderin g th e laboratory tests, it is un likely th at such testin g will be h elpful an d (2) it is rarely appropriate to perform an exten sive laboratory evaluation wh en a person initially presents with a joint pain. Th ere are several reason s for th e stron g n ote of caution regardin g diagn ostic testin g in patien ts wh o presen t with join t pain . Un fortun ately, th ere are virtually n o diagn ostic tests th at can be ordered in th is settin g th at fun ction well as screening tests; m ost of the laboratory studies done in th e evaluation of person s with join t pain h ave a relatively low positive or negative predictive value unless they are ordered in th e appropriate settin g. Luckily, in m ost rh eum atic disorders, it is n ot n ecessary to m ake a defin itive diagn osis before in itiating treatm en t. This com bination of poor diagn ostic utility of frequen tly ordered tests, an d th e fact th at treatm en ts can be in itiated before diagn oses are establish ed, is som ewhat un usual when compared with other fields of m edicine. A suggested diagn ostic approach to patien ts with joint pain is to first con sider wh eth er patien ts m ay h ave an in fection or m alignancy causing th eir symptom s. It is im portan t to recogn ize th at it is un usual for person s wh o are not im m unocomprom ised (e.g., HIV infection, m align an cy) or without som e recen t surgical even t or traum a to a joint to develop septic arthritis. The exceptions to this are dissem inated gonococcal infection, Lym e disease, and tuberculous arthritis, which can occur in persons with intact im m un e system s an d n o oth er risk factors. If a septic join t is suspected, th en th e study of ch oice is to perform an arth rocentesis and synovial fluid an alysis. If a m align ancy is suggested, for example, because of weight loss or other system ic symptom s, then im aging studies of th e involved region sh ould be perform ed im m ediately, followed by a biopsy in m ost settin gs. On ce those individuals with infection and m align ancy h ave been iden tified, the next con sideration is wh eth er th ey m ay have a life-threatenin g (or organ-threatening) autoim m une disorder. These individuals will rarely present with n onspecific symptom s an d m ild im pairm en t but in stead will appear an d feel very ill. In th is settin g, th e workup sh ould be guided by th e presenting symptom s, with particular attention to detecting organ involvem ent (e.g., cardiopulm on ary, cen tral n ervous system [CNS], ren al) th at m ay require specific and aggressive intervention . This is also the settin g where extensive diagnostic testing for the presen ce of autoan tibodies, complem en t, an d oth er studies (e.g., antineutrophil cytoplasm ic an tibodies for system ic vasculidities) is likely to be helpful in rapidly establishing a diagn osis an d initiating aggressive treatm en t. If th e h istory an d physical exam in ation suggest th at a person m ay suffer from a system ic autoim m un e disorder, th en a gen eral set of screen in g laboratory studies can be h elpful. A reason able ch oice would in clude a complete blood cell (CBC) coun t, ren al an d h epatic studies, urin alysis, an d screen for acute ph ase reactan ts. Th e m ost


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TABLE 7.4

USE OF GROSS ANALYSIS, MUCIN CLOT TEST, AND TOTAL AND DIFFERENTIAL LEUKOCYTE COUNTS IN THE CLASSIFICATION OF SYNOVIAL FLUIDS Criteria

Normal

Noninflammatory (Group I)

Volume (mL) (knee) Color Clarity Viscosity Mucin clota Spontaneous clot Leukocytes per mm3 Polymorphonuclear leukocytes (%)

<4 Clear to pale yellow Transparent Very high Good None < 50 < 25

Often > 4 Xanthochromic Transparent High Fair to good Often < 3,000 < 25

Inflammatory (Group II)

Purulent (Group III)

Often > 4 Xanthochromic to white Translucent to opaque Low Fair to poor Often 3,000–50,000 > 70

Often > 4 White Opaque Very low Poor Often 50,000–300,000 > 90

a

A bedside test for indicating viscosity of synovial fluid – the more viscous and “stringy” the fluid is when it is dripped the more normal. (Reprinted with permission from Koopman WJ, Moreland LW. Arthritis and Allied Conditions: A Textbook of Rheumatology. 15th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)

com m only ordered tests th at assess acute phase reactants are the erythrocyte sedim entation rate (ESR) and the Creactive protein (CRP). As n oted previously, tests for ANA an d RF, and for other autoantibodies, should generally be reserved for person s with objective features suggestin g autoim m un e disorders or in wh om th is in itial screen in g in dicates abn orm alities. Th e ESR is a n on specific m easure of inflam m ation that is inexpensive and easy to m easure, but the results of this test m ust be interpreted with caution. The rate at wh ich RBCs sedim en t in an ticoagulated blood depen ds on m any factors but in m ost settin gs is closely related to th e plasm a con cen tration of acute ph ase protein s, with fibrin ogen bein g th e m ost im portan t. Alth ough a Westergren sedim en tation rate of greater th an 20 m m / h is gen erally con sidered to be abn orm al, th ere are m any factors, such as n orm al agin g, that m ay cause m ild elevations in this value. Other noninflam m atory factors that can influen ce th e ESR in cludin g an em ia (elevated), polycyth em ia (decreased), pregnancy (elevated), drugs (h eparin and valproic acid level elevated), or ch an ges in sh ape of RBC (decreased). Very high the ESRs (e.g., m ore than 100 m m / h) are typically seen only in inflam m atory disorders, infection, an d m alignancy. Th e CRP is a sin gle plasm a protein th at is produced in the liver in response to various types of tissue injury. The advantage of m easuring this protein in stead of the ESR is that th ere are fewer noninflam m atory stim uli that cause an elevation of the CRP, and th is value will rise and fall m ore rapidly in respon se to inflam m atory stim uli. The norm al CRP value is less than 1 m g/dL. Values between 1 and 10 m g/ dL are seen in a variety of in flam m atory states, wh ereas values above 10 m g/ dL are usually (but n ot always) in dicative of infection.

Synovial Fluid Analysis Th e aspiration of an in volved join t an d an alysis of extracted syn ovial fluid can be particularly helpful in assessing th e

person with arth ritis. In addition to a CBC coun t an d a differen tial count, the appearan ce and viscosity of th e fluid sh ould be assessed, an d th e protein and glucose concentration in th e fluid sh ould be determ in ed. Gram stain in g an d culture are useful for th e diagn osis of septic arth ritis, wh ereas exam inin g th e fluid un der a polarizin g m icroscope allows detection of crystals respon sible for crystal-in duced arth ropathy, for example, gout an d pseudogout. Tables 7.4 an d 7.5 in dicate h ow th is in form ation can be used, togeth er with th e h istory, physical exam ination, and oth er diagnostic tests, in assessin g th e patien t with arth ritis.

RHEUMATOLOGIC DISORDERS A brief overview of a n um ber of rh eum atic disorders th at m ay presen t with orthopaedic problem s is given in th e following section. Space constraints severely lim it both the breadth an d depth of th is section , an d th e reader sh ould refer to several excellen t rh eum atology textbooks for a m ore extensive overview of th ese and other rheum atologic disorders.

Rheumatoid Arthritis RA is the m ost com m on form of chronic, system ic inflam m atory arthritis. It is estim ated th at 1% to 2% of th e population worldwide suffers from th is disorder. Population based studies m ay overestim ate th e prevalen ce of “true’’ RAs, as m any people identified in such studies m ay have self-lim ited form s of inflam m atory arth ritis (e.g., postviral arth ritis) or do n ot h ave in flam m atory arth ritis at all. Non eth eless, th is is likely th e m ost com m on autoim m un e rh eum atic disease. As with m ost autoim m un e disorders, wom en are affected m ore com m on ly th an m en , with a ratio of approxim ately 2.5 to 1. RA can strike at any age, from th e youth to the elderly. As with m ost autoim m une disorders,

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TABLE 7.5

EXAMPLES OF RHEUMATIC CONDITIONS PRODUCING DIFFERENT TYPES OF SYNOVIAL FLUID Noninflammatory (Group I)

Inflammatorya (Group II)

Purulenta (Group III)

Hemorrhagic (Group IV)

Osteoarthritis Early rheumatoid arthritis Trauma Osteochondritis dissecans Osteonecrosis pigmented Osteochondromatosis Crystal synovitis; chronic or subsiding acute (gout and pseudogout) Systemic lupus erythematosusb Polyarteritis nodosab Scleroderma disease Amyloidosis (articular) Polymyalgia rheumatica High-dose corticosteroid therapy

Rheumatoid arthritis Reactive arthritis Crystal synovitis, acute (gout, pseudogout, other) Psoriatic arthritis Arthritis of inflammatory bowel disease Viral arthritis Rheumatic fever Behçet disease Fat droplet synovitis Some bacterial infections, e.g., coagulase-negative Staphylococcus, Neisseria, Borrelia, Moraxella

Bacterial infections Tuberculosis Pseudosepsis

Trauma, especially fracture Neuroarthropathy (Charcot joint) Blood dyscrasia (e.g., hemophilia) Tumor, especially villonodular synovitis or hemangioma Chondrocalcinosis Anticoagulant therapy Joint prostheses Thrombocytosis Sickle cell trait or disease Myeloproliferative Milwaukee shoulder syndrome

(Reprinted with permission from Koopman WJ, Moreland LW. Arthritis and Allied Conditions: A Textbook of Rheumatology. 15th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)

the cause of RA is unknown. Gen etic risk factors play som e role, in th at m on ozygotic twin s sh ow an 11-fold risk over dizygotic twin s, an d th e m ajority of in dividuals wh o develop th is disorder h ave th e HLA DR4 an d/ or DR1 epitope. Specific “susceptibility cassettes,’’ or sh ared epitopes on th e β ch ain s of DR, such as DRB*0401, DRB*0404, DRB*0101, an d DRB*1402, carry th e greatest association with RA. But gen etic factors play a relatively sm all overall role, sin ce even in dividuals with a positive fam ily h istory of RA an d on e of th e putative HLA epitopes h ave a low absolute risk of developin g th is disorder. It h as lon g been suspected that the com bin ation of these genetic im m un e risk factors and subsequent exposure to infectious agents lead to th e developm en t of disease. However, n o in fectious agen ts h ave curren tly been clearly iden tified as bein g causal in RA. The hallm ark of RA is the presen ce of a chronic polyarticular, inflam m atory arthritis. This can begin either abruptly or m ore in dolen tly an d can begin in sm all or large join ts. Th e presen ce of in flam m atory arth ritis can be docum en ted by th e fin din g of syn ovitis on exam in ation , th e fin din g of in flam m atory (wh ite blood cell [WBC] coun t > 2,000 cells/ m m 3 ) synovial fluid, or the radiographic appearan ce of ch aracteristic erosion s (n ot presen t un til later in the course of the illness). If the diagnosis of RA is m ade prim arily on th e basis of th e physical exam in ation , th en it m ust be clear that synovial proliferation is present there, n ot just tendern ess over th e joint. Th e 1987 revised Am erican Rh eum atism Association criteria for th e classification of RA in clude som e of th e m ost important clin ical features of this disorder (Table 7.6). Although prolonged m orning stiffness occurs in nearly all cases of RA, this is observed in a num ber of other inflam -

m atory an d n on in flam m atory disorders an d is n ot specific for this diagnosis. Three of th e criteria are related to the fact that RA usually involves the sm all joints of the h and an d typically is relatively equally distributed on both sides of th e body (i.e., sym m etric). Th e join ts in itially an d ultim ately in volved in RA are listed in Figure 7.3. In patien ts with polyarticular in flam m atory arth ritis, laboratory an d radiograph ic testin g can be h elpful to m ake a specific diagnosis. RF is foun d in approxim ately 80% of person s with RA. Th e presen ce of RF is h elpful because it m akes it m uch m ore likely th at RA is th e m ost likely diagn osis, an d RA patien ts who are RF positive are m ore likely to h ave severe disease as well as extraarticular features such as rh eum atoid n odules, in terstitial lun g disease, an d Felty syn drom e. But on ce RF is found to be positive, th ere is no reason to order th e test sequen tially, because th e titer does n ot correlate with disease activity. Anti-CCPs m ay be positive earlier th an RF in th e course of th e disease or m ay be th e on ly positive serological fin din g in patien ts wh o rem ain RF n egative. These antibodies appear to be m ore specific th an RF an d also predict an erosive course of RA. An oth er test th at is h elpful in th is settin g is testin g for the IgM titer for parvovirus infection (especially if patients h ave been exposed to ill children), since an acute parvovirus in fection in adults can cause an in flam m atory arth ritis th at resem bles RAbut rem its in several m on th s. In areas th at are en dem ic for Lym e disease, Lym e titers m ay be a h elpful test, especially in th ose with a h istory of a tick bite or rash or those with m ono- or oligoarticular large joint in volvem en t. Early in RA, radiograph s are n ot likely to sh ow th e ch aracteristic erosion s seen late in th e disease. Th e m ost com m on radiograph ic fin din g in early RA is a n orm al radiograph, with soft tissue swelling. Periarticular osteopenia is


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TABLE 7.6

1987 AMERICAN COLLEGE OF RHEUMATOLOGY REVISED CRITERIA FOR THE CLASSIFICATION OF RHEUMATOID ARTHRITIS (TRADITIONAL FORMAT)a Criterion

Definition

Morning stiffness Arthritis of three or more joints Arthritis of hand joints Symmetric arthritis

Morning stiffness in and around the joints, lasting at least 1 hour before maximal improvement At least three joint areas simultaneously with soft tissue swelling or joint fluid observed by a joint areas physician; the 14 possible areas are (right or left): PIP, MCP, wrist, elbow, knee, ankle, and MTP joints At least one area swollen in a wrist, MCP, or PIP joint Simultaneous involvement of the same joint areas on both sides of the body (bilateral involvement of PIP, MCP, or MTP acceptable without perfect symmetry) Subcutaneous nodules over bony prominences or extensor surfaces, or in juxtaarticular regions, observed by a physician Abnormal amount of serum rheumatoid factor by any method for which the result has been positive in < 5% of control subjects Erosions or unequivocal bony decalcification localized in or most marked adjacent to the involved joints (osteoarthritis changes excluded), typical of rheumatoid arthritis on posteroanterior hand and wrist radiographs

Rheumatoid nodules Serum rheumatoid factor Radiographic changes

MCP, metacarpophalangeal; MTP, metatarsophalangeal; PIP, proximal interphalangeal. a For classification purposes, a patient is said to have rheumatoid arthritis if four of seven criteria are satisfied. Criteria 1 to 4 must have been present for at least 6 weeks. Patients with two clinical diagnoses are not excluded. (From Arnett FC, Edworth SM, Bloch DA, et al. The American Rheumatism Association 1987 revised criteria for the classification of rheumatoid arthritis. Arthritis Rheum. 1988;31:315–324, with permission.)

the next m ost com m on finding. The involvem ent of certain join ts by RA bears special m en tion . Cervical spin e in volvem en t is relatively com m on and is the source of significant m orbidity and m ortality. Th e m ost serious involvem ent involves C1 (particularly th e transverse ligam ent) and C2 (especially the odon toid process), leading to C1 –C2 in stability. This should be considered in patien ts with established RA who present with n eck pain and/ or myelopathic symptom s or findin gs. Patients with longstanding RA wh o

Figure 7.3 The joint distribution

of the two most common forms of arthritis—rheumatoid arthritis (RA) and osteoarthritis (OA)—are compared and contrasted. Joints involved in these arthritides are noted by the black circles over involved joint areas. (Reprinted with permission from Koopman WJ, Moreland LW. Arthritis and Allied Conditions: A Textbook of Rheumatology. 15th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)

are un dergoin g surgery th at in volves in tubation sh ould be screen ed for this com plication. These patients should have flexion –exten sion radiograph s of th e cervical spin e taken , an d th ose with a preodon toid space of greater th an 5 m m , an in adequate space available for th e cord, or in stability sh ould be considered for surgical in tervention. Han d in volvem en t is very com m on in RA. Although the DIP joints are rarely in volved in th is disorder, n early all other h and join ts are com m on ly in volved. Th e

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ch aracteristic deform ities seen in th e digits (e.g., swan neck deform ity, boutonn iere deform ity, and ulnar deviation at th e m etacarpoph alan geal [MCP] join ts) are due to a com bin ation of join t destruction an d laxity of ligam en ts an d ten don s. Ten osyn ovitis com m on ly can lead to clin ical symptom s in RA, especially “trigger fingers’’when the flexor ten don s of th e digits are in volved. Extraarticular m anifestations of RA are also com m on, especially in person s with a positive serum RF. Rh eum atoid nodules m ost com m on ly occur on th e exten sor surfaces of the arm in the olecranon region but can occur nearly anywhere in the body, particularly on oth er exten sor surfaces. Th e form ation of n odules can becom e accelerated in person s with RA given m eth otrexate. There are a variety of form s of pulm on ary disease in RA. As with m any cardiopulm on ary m an ifestation s in patien ts with autoim m un e disorders, th is occurs in n early all RA patien ts in autopsy series but is less com m on ly clin ically apparent. Interstitial fibrosis preferentially involving the basilar regions is m ost com m only seen. Pleural involvem en t, n odules in th e lun g (especially fulm in an t in coal m in ers an d term ed Caplan syn drom e), an d bron ch iolitis obliteran s are also seen . Cardiac in volvem en t, wh ich m ay in clude pericarditis, myocarditis, an d cardiac conduction defects (perh aps due to rh eum atoid n odules in volvin g th e con duction system ), can be seen in RA. Vasculitis m ay also occur in person s with RA, and in th is settin g, it is term ed rheumatoid vasculitis. Th is can involve both sm allan d m edium -sized vessels of the skin, peripheral n erves, and visceral organs. Felty syn drom e is th e com bin ation of RA, splen om egaly, isch em ic leg ulcers, an d n eutropen ia. Th ese person s also com m only exhibit lymphadenopathy and throm bocytopenia, and som etim es splenectom y is necessary for effective treatm en t. The natural history of RAhas becom e better understood recen tly an d h as led to con sideration of differen t treatm en t paradigm s. It h as becom e in creasin gly clear th at m uch of the joint dam age in RA occurs in th e first several years of the illness. Th us, old “pyram id’’ treatm en t strategies that slowly added one drug at a tim e have been replaced by m ore aggressive paradigm s. Also, in th e past, RA h ad been considered an indolent, debilitating disorder characterized by a slow progressive course, with eventual rem ission in som e patients. It is now clear that patien ts with RA h ave significantly increased m ortality and die 10 to 15 years earlier th an expected. Th is excess m ortality appears to be m ultifactorial, in cludin g an in creased risk of in fection s, cardiovascular disease, and pulm onary and gastrointestinal (GI) complications. There is no unanim ity on exactly how to treat RA, but nearly all persons with out a con train dication to taking non steroidal anti-inflam m atory drugs (NSAIDs) will benefit from takin g this class of m edication . It is un usual for RA to be con trolled with th is agen t alon e, an d in m ilder disease, a logical step is to add hydroxych loroquin e (200 m g

twice daily). The principal concern with this agen t is retin al toxicity. Hen ce, twice-yearly oph th alm ologic exam inations are typically recom m ended. For patients with m ore aggressive disease or those who fail hydroxychloroquine, weekly m eth otrexate is a logical n ext ch oice. Th is m edication is typically given orally on ce weekly, begin n in g at 7.5 m g per week an d escalatin g as h igh as 20 m g or m ore per week. Folic acid is typically coadm in istered at 100 m g/ d to h elp avoid GI toxicity. Sh ort-term side effects of th is m edication include diarrhea, nausea, fatigue, and stom atitis, wh ereas th e m ore serious toxicities are liver disease an d hypersen sitivity pn eum on itis. Leflun om ide, wh ich acts as an antipyrim idine agent, is of sim ilar effectivity (and toxicity). When and where to use corticosteroids in the chronic treatm ent of RArem ains controversial, with som e data suggestin g th at lon g-term , low-dose (e.g., < 10 m g/ d of predn isone) is both helpful an d relatively free of side effects. Th e treatm en t of RA h as been revolution ized over th e last decade due to the introduction of biologic anticytokin e m edications into com m on clinical use. Three m edications th at act by n eutralizin g th e activity of TNF-α h ave been in troduced (inflixim ab, etan ercept, and adalim um ab). These agen ts, which are adm inistered by the intravenous or subcutan eous route, h ave proven extrem ely effective in cases refractory to con ven tion al m edication s. Sin ce th ese drugs inhibit a m ajor component of the im m une system , th eir use m ay expose th e patien t to in fection with path ogen s such as Mycobacterium tuberculosis. Prior in fection with th is path ogen m ust, th erefore, be ruled out before in itiatin g such treatm en t. Another biologic agent that has been recently introduced for th e treatm en t of RA is rituxim ab, wh ich acts by targetin g B-cell lym ph ocytes, wh ich express th e CD20 an tigen . Th is m edication , origin ally developed for th e treatm ent of B-cell m align ancies, can brin g about lon g-term clin ical rem ission (lastin g up to 1 year) after a sin gle in fusion . In troduction of additional classes of biological agents, includin g inhibitors of IL-1, IL-6, and so on, is likely to furth er im prove th e m an agem en t of RA.

Osteoarthritis OA likely represen ts a n um ber of differen t path ologic processes, all characterized by progressive loss of articular cartilage and new bone form ation in the subchondral region (sclerosis) and the join t m argins (osteophytes). OA is the m ost com m on joint disease, affecting the m ajority of people (in som e site) older th an 65 years an d n early all people older th an 80 years. Alth ough in creasin g age is th e sin gle largest risk factor for OA, other genetic and en viron m ental factors play a role, especially for certain join ts. For exam ple, gen etic factors play a sign ifican t role in OA of th e h an ds, especially in wom en . In th e kn ee, gen etic factors play a m in or role. For this join t, obesity decreased m uscle strength in the quadriceps and a history of m ajor kn ee traum a are the m ost con sistently iden tified risk factors. Although m ajor


traum a to any join t can lead to OA and certain occupations have an increased incidence of OA, use in general, an d even m ild overuse, is not a risk factor for OA. Th e precise path ologic m ech an ism s leadin g to OA are un clear. Most believe th at th is disease process is a result of an interaction between abn orm al biology of cartilage and bon e an d/ or abn orm al forces bein g applied to th e join ts. With respect to biology, on e of the earliest chan ges seen in OA is increased cartilage th ickn ess. Th is early in crease in thickness is likely due to in creased water content of th e cartilage due to disruption of th e collagen network. Ch on drocytes respon d to th is process by in creasin g proteoglycan syn thesis. This early phase of cartilage hypertrophy is followed by loss of cartilage and a decrease in proteoglycan syn thesis. In the early stages of cartilage loss, sm all crevices or clefts develop in cartilage, an d with con tin ued tim e an d use, th ese clefts deepen an d widen , wh ereas ch on drocytes cluster, form ing “clones’’of cells. Finally, there is complete loss of cartilage and bone denudation . Bon e responds in a num ber of ways to th e cartilage chan ges th at occur in OA. Appositional bone growth occurs in the exposed subchondral region s, leadin g to sclerosis. At th e join t m argin s, bon e an d cartilage grow an d lead to osteophyte form ation. Abnorm al forces can lead to th e developm ent of OA, even if biology is n orm al. Th e exam ples of OA caused by traum a or repetitive activities are eviden ce of th is ph en om en on . Once OA has begun, wh eth er the initial problem is biological or m echan ical, abn orm al forces usually play a role. Th is is particularly true in weigh t-bearin g join ts. Th e diagn osis of OA is based on appropriate symptom s an d radiograph ic findings. The m ost com m on symptom of OA is pain . Th e pain is frequen tly deep, ach in g, an d poorly localized. Early in th e course of th e illn ess, pain will typically occur prim arily with use of th e affected join t, wh ereas later in th e disease, pain m ay occur even at rest. Because OAis not an in flam m atory condition , there is m in im al (i.e., less than 30 m inutes) m orn ing stiffn ess. Other symptom s m ay include crepitus, lim itation of m otion , an d “givin g way’’ of joints. Plain radiograph s rem ain th e “gold stan dard’’ for diagnosin g OA, although there are several caveats necessary to interpret this inform ation correctly. The classic findings in OA are join t space n arrowin g (in m any cases asym m etric), sclerosis of subchondral bone, and form ation of m argin al osteophytes an d cysts. Studies th at h ave com pared th e results of radiographs with the fin din gs on arthroscopy have dem on strated th at m ild ch an ges of OA m ay be visualized via arth roscopy or on m agnetic resonance im aging (MRI) exam ination before any radiographic abnorm alities are present. This is not of substan tial clinical con sequen ce because m ost of th ese person s are asym ptom atic. A larger problem with interpretin g radiographs is that a m inority of people with radiograph ic evidence of OA will be symptom atic. The reason for this disparity between radiograph ic ch an ges an d th e presen ce of pain an d disability is not clear, and this discrepan cy is n ot seen on ly in OA but

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also in n early any ch ron ic pain con dition . Non eth eless, this points out that treatm ents such as those described for n on an atom ic pain syn drom es such as fibromyalgia should be con sidered for n on m ech an ical m ech an ism s th at m ay be operative in m any patien ts wh o presen t with pain an d are found to have OA and in patients in whom th ere is a poor relation sh ip between symptom s an d path ology. Th e m an agem en t of OA is prim arily n on surgical, un til very late in th e disease. Several n onph arm acologic th erapies h ave been sh own to be effective in ran dom ized con trolled trials, in cludin g patien t education , weigh t loss (in person s wh o are obese, particularly for th e kn ee), stren gth en in g exercises (again especially for th e kn ee), an d aerobic exercise. Topical application s of h eat or cold can be a h elpful adjun ct in som e patients. The use of various orthotics, in cludin g in soles, braces, h eel lifts, an d splin ts can be of sign ifican t use in th e appropriate situation s. Likewise, the use of a can e can im prove pain origin atin g from h ip OA. O th er n onph arm acological strategies for com batin g pain in OA such as spa th erapy, acupuncture, and tran scutaneous electrical n erve stim ulation m ay offer pain relief to OApatien ts, alth ough th ey are less well–eviden ce-based. Th e Arth ritis Foun dation h as establish ed m any of th ese program s an d is a valuable resource for th is type of patien t in form ation . In person s wh o do n ot respon d to n onph arm acologic therapy, acetam in ophen is often effective. In patients who fail acetam inophen alone, topical capsaicin cream or intraarticular corticosteroids can be con sidered, especially for the kn ee joint. If these treatm ents are in effective, then use of low-dose NSAIDs, followed by h igh -dose NSAIDs, is a reason able option (see “Ph arm acologic Th erapy’’). Several n ew therapies for OA of th e kn ee h ave recen tly em erged, an d th eir place in th e treatm en t algorith m rem ain s un clear. Multiple sm all, ran dom ized con trolled trials studies h ave suggested that glucosam ine and chon droitin sulfate m ay be effective in relievin g pain in OA of th e kn ee. Large-scale studies are n ow being conducted to confirm th ese fin dings. Several in traarticular hyaluron ic acid preparation s for th e use in kn ee OA are available. Th ese products m ust be given with a series of in jection s and were shown to be m ore effective than sham injection and the use of acetam inophen. Th is treatm en t m odality m ay be m ost effective in th ose who h ave a con traindication to usin g an NSAID or th ose wh o h ave failed a trial of several NSAIDs. Th e use of n arcotic an algesics is usually reserved for severe cases of OA that fail to obtain satisfactory relief from other m edications and treatm ent m odalities. Careful patient selection is important due to the side effects of th ese m edication s (particularly in elderly patien ts). Th e outstan din g progress m ade over recen t years in th e treatm en t of in flam m atory join t disease such as RA h igh ligh ts the relative paucity of options currently available for in fluen cin g th e actual process of cartilage degradation , wh ich is th e h allm ark of OA. A n um ber of treatm en ts h ave been studied for th is indication, including tetracyclines, growth factor an d cytokin e m an ipulation, and the use of diacerein,

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a drug th at in h ibits th e syn th esis of IL-1β an d is in use for treatm en t of OA in Europe. Non e of th ese m odalities are currently available in the United States.

Fibromyalgia and Regional Soft Tissue Rheumatism Fibrom yalgia is th e secon d m ost com m on rh eum atic con dition in th e Un ited States, after OA. It affects approxim ately 2% of th e population : wom en m uch m ore th an m en . In th e classic form , th is con dition is ch aracterized by widespread m usculoskeletal pain and diffuse soft tissue ten dern ess. Th e Am erican College of Rh eum atology criteria for this illness require that persons h ave pain throughout the entire body, as well as in 11 of 18 “ten der points,’’ but m any person s with th e clin ical diagn osis of fibromyalgia will exh ibit pain only in few regions of their body or h ave less th an 11 ten der poin ts. A diagnosis of fibromyalgia should be suspected when a person presents with m ultifocal pain with n o eviden ce of in flam m ation or dam age to periph eral structures on physical exam in ation an d/ or furth er diagn ostic workup. O th er clinical features that occur com m only in the setting of fibromyalgia are fatigue, in som n ia, m em ory or con cen tration difficulties, h eadach es, an d irritable bowel sym ptom s. It is also com m on to fin d a lifetim e h istory of ch ron ic pain in localized region s of th e body, such as th e n eck or back an d temporom an dibular join t. A stron g fam ilial association h as been observed in fibromyalgia, an d eviden ce sh ows th at th ere is a sign ifican t gen etic un derpin n in g for th is syn drom e. At th e sam e tim e, a large n um ber of en vironm ental stim uli, including infection (viral an d oth er), physical traum a, an d stress can act as triggers for th e developm en t of fibromyalgia in gen etically predisposed in dividuals. Routin e laboratory testin g will be n orm al in th is con dition , an d im agin g studies will eith er be n orm al or detect abn orm alities of un certain clin ical sign ifican ce (e.g., m ild degen erative ch an ges, bulgin g discs). There is considerable evidence that the pain in fibromyalgia occurs because of a disorder in th e cen tral n ervous system processin g of sen sory stim uli, an d th us, th is condition typically does not respond to analgesics that act prim arily in th e periph ery, such as acetam in oph en , NSAIDs. Th us, th e cen tral n ervous system fails to properly atten uate in com in g pain ful stim uli at th e level of th e spin al cord, and alteration s in levels of pain-related neurotran sm itters, such as n orepin eph rin e, seroton in , an d substan ce P are observed in the cerebrospinal fluid of fibromyalgia patien ts. Medication s th at act by m an ipulatin g th e con cen tration of th ese n eurotran sm itters in th e cen tral n ervous system , for example, norepin eph rin e–seroton in reuptake in h ibitors, are m ost effective in alleviatin g th e pain of fibromyalgia. Low doses of tricyclic drugs such as cycloben zaprin e (Flexeril) an d am itriptylin e (Elavil) given at bedtim e can

be effective an algesics in th is settin g. Th ese drugs sh ould be initiated at very low doses (e.g., 10 m g), given several hours before bedtim e an d escalated slowly (e.g., 10 m g every 1 to 2 weeks). Th e m axim um dose is 40 m g of cycloben zaprin e, or approxim ately 70 m g of am itriptylin e, but side effects of dry eyes an d m outh , m orn in g sedation , con stipation , and weight gain often prevent dose escalation . Tram adol (Ultram ), which acts both as a weak opioid and as a reuptake in h ibitor, can also be used for pain relief. An tiepileptic drugs, which are widely used in th e treatm ent of various chronic pain conditions, have been proven to be effective in fibromyalgia. In a random ized, double-blinded, placebocon trolled trial, pregabalin (Lyrica) dem on strated efficacy again st pain, sleep disturbances, and fatigue as compared with placebo in fibromyalgia. Pregabalin h as been th e first m edication to gain the U.S. Food and Drug Adm inistration (FDA) approval for th e treatm en t of fibromyalgia, whereas gabapentin, an older antiepileptic drug used for treatm ent of posth erpetic n euralgia, appears to be of sim ilar efficacy. Dual reuptake in h ibitors, wh ich act by elevatin g levels of n orepin eph rin e an d seroton in in th e CNS, are gain in g rapid popularity in th e treatm en t of fibrom yalgia. Most recen tly, duloxetin e (Cym balta) an d m iln acipran (Savella) h ave gain ed FDA approval for th is in dication , an d additional dual reuptake inhibitors are likely to be in troduced in the near future. Low-impact aerobic exercise can be particularly useful, but as with th e tricyclic drugs, th is sh ould be started very slowly an d in creased very gradually. Cognitive beh avioral th erapy or oth er structured pain m an agem en t program s are also very beneficial, particularly for com bating the negative function al aspects of fibromyalgia.

Seronegative Spondyloarthropathies Th e four classic SSs are an kylosin g spon dylitis, reactive arthritis, inflam m atory bowel disease–associated arthropathy, an d psoriatic arth ritis. These disorders are considered togeth er because th ey sh are an im m un ologic predisposition (HLA-B27) that leads to both (1) sim ilar articular features (an inflam m atory arthritis involvin g the axial skeleton ), an d (2) com m on extraarticular features (e.g., inflam m atory eye disease, cardiac conduction defects, aortic valve disease). Even th e approxim ately 80% of individuals wh o are HLA-B27 –positive do n ot develop a SS h ave an independent risk of developin g the classic extraarticular features seen in this spectrum of illn ess.

Ankylosing Spondylitis Ankylosing spondylitis is the prototypical disease in this category. Th e characteristic features of this illness are shown in Table 7.7. Th e earliest joint involved in m ost persons with this disorder is the sacroiliac join t. Clinically, these individuals will com plain of in dolen t on set of m orn in g stiffn ess an d pain in volving the low back, which typically improves with exercise. O th er ch aracteristic features of th e pain seen


TABLE 7.7

CLASSIFICATION CRITERIA FOR ANKYLOSING SPONDYLITIS Amor Classification for Spondyloarthropathiesa Clinical systems/past history (score). Requires a score of 6 for spondyloarthropathy Lumbar/dorsal pain at night; morning stiffness (1) Asymmetrical oligoarthritis (2) Buttock pain (1) Sausage-like toe/digit (2) Heel pain/enthesopathy (2) Iritis (2) Nongonococcal urethritis/cervicitis < 1 mo (1) Acute diarrhea < 1 mo (1) Psoriasis, balanitis, IBD (2) Radiologic findings (2) Sacroiliitis (bilateral grade 2 or unilateral grade > 2) Genetic background (2) HLA-B27 positive Family history of AS, REA, IBD, psoriasis, or uveitis Response to treatment (2) Clear-cut improvement (within 48 h) with NSAIDs European Spondyloarthropathy Study Group Criteria for Spondyloarthropathiesb 1. Inflammatory spinal pain 2. Synovitis (symmetric or predominantly lower limbs) One or more of the following (in addition to criterion 1 or 2): Alternate buttock pain, sacroiliitis enthesopathy, positive family history, psoriasis, IBD, urethritis/cervicitis/diarrhea < 1 month prior Modified New York Criteriac Low-back pain of 3 months’ duration improved by exercise and not relieved by rest Limitation of lumbar spine in sagittal and frontal planes Chest expansion decreased relative to normal values for age and sex Bilateral sacroiliitis, grade 2–4d Unilateral sacroiliitis, grade 3–4d Definite AS if unilateral grade 3 or 4 or bilateral grade 2–4 sacroiliitis and any clinical criteria AS, ankylosing spondylitis; IBD, inflammatory bowel disease; NSAID, nonsteroidal anti-inflammatory drug; ReA, reactive arthritis. a Amor B, et al. Rev Rhum Mal Osteoartic. 1990;57:85–89. b Dougados M, van der Linden S, Juhlin R, et al. The European Spondyloarthropathy Study Group preliminary criteria for the classification of spondyloarthropathy. Arthritis Rheum. 1991;34:1218–1227. c van der Linden S, Valkenburg HA, Cats A. Evaluation of diagnostic criteria for ankylosing spondylitis. Arthritis Rheum. 1984;27:361–367. d Grading of radiographs: 0 = normal; 1 = suggestive; 2 = minimal sacroiliitis; 3 = moderate sacroiliitis; 4 = complete ankylosis. (From Dawes PT. Stoke ankylosing spondylitis spine score. J Rheumatol. 1999;26:993–996.)

in ankylosing spon dylitis, as well as the symptom s that help differen tiate m ech an ical back disease from in flam m atory back disease, are sh own in Table 7.8. O n physical exam in ation , in dividuals with sacroiliac in volvem ent will usually dem onstrate lim ited m otion in this area of the body. Th e m ost com m on ly perform ed test to dem on strate th is is th e m odified Sch ober test. In th is test, a m ark is m ade on the skin overlying the spine wh ere an

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TABLE 7.8

FEATURES OF INFLAMMATORY BACK PAIN Younger age at onset of pain (peak 26 y) Pain and early morning stiffness of the spine Improvement with exercise/activity Insidious in onset Symptoms lasting for more than 3 mo Spinal mobility and deep breathing may be restricted Radiographic evidence of sacroiliitis or ankylosis Reprinted with permission from Koopman WJ, Moreland LW. Arthritis and Allied Conditions: A Textbook of Rheumatology, 15th ed. Philadelphia: Lippincott Williams & Wilkins, 2005.

im aginary line would connect the left and righ t posterior iliac spin es. An oth er dot is placed 10 cm higher, an d the patien t is asked to m axim ally flex forward. Th e distan ce in n orm al individuals sh ould in crease to at least 15 cm , an d if not, it suggests th at there is som e lim itation of m otion in th is region . Th e classic radiograph ic fin din gs of an kylosin g spon dylitis include sacroiliitis, enthesopathy (periostitis at ten don an d ligam en t in sertion s), an d an kylosis (fusion ) (Figs. 7.4 an d 7.5). Early cases of sacroiliitis th at cannot be detected by con ven tion al radiography are visible on gadolinium -enh anced MRI exam ination. In the spine, the initial change seen is a loss of concavity of vertebral bodies due to en th esopath ic disease, even tually followed by fusion , leadin g to th e classic “bam boo spin e.’’It is importan t to differentiate this finding from that of diffuse idiopathic skeletal hyperostosis, in which th e hyperostoses are thicker and typically on ly involve the right side of the thoracic spin e. In addition to an inflam m atory arthritis in volving th e axial skeleton , patien ts with an kylosin g spon dylitis m ay also develop peripheral join t involvem ent. Fem ale patien ts m ay be m ore likely than m ale patients to have prim arily periph eral join t in volvem en t an d isolated cervical in volvem ent. Th e extraarticular m an ifestation s of an kylosin g spon dylitis are sim ilar to those that can occur in other seron egative arthropath ies. Inflam m atory anterior eye disease (uveitis or iritis) typically presen ts with un ilateral eye pain , ph otoph obia, an d blurred vision . Cardiac con duction defects m ay occur in up to 7% of patien ts with long-standing disease and aortic insufficien cy in 10% of patien ts with ch ron ic disease. In terstitial lun g disease in th is illn ess h as an un usual predilection for th e upper lobes. Neurologic in volvem en t is rare but can be catastroph ic, usually wh en a patien t with a fused spin e is in volved in traum a, and m ay present with paresis. Laboratory testing is generally unhelpful, except in som e cases to rule out oth er disorders. In flam m atory in dices such as an ESR an d a CRP m ay be elevated. In persons with in flam m atory periph eral arth ritis, an RF (wh ich will be n egative, th us th e term seronegative spondyloarthropathy)

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Figure 7.4 Anteroposterior radiograph of the upper pelvis and

lumbar spine. Both sacroiliac joints (large arrows) are fused (grade IV sacroiliitis), and there are bilateral, symmetric syn-desmophytes (small arrow), resulting in the typical “bamboo” appearance of ankylosing spondylitis. (Reprinted with permission from Koopman WJ, Moreland LW. Arthritis and Allied Conditions: A Textbook of Rheumatology. 15th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)

is useful. Testin g for HLA-B27 is rarely in dicated, because this haplotype is seen in approxim ately 6% of Caucasians (lesser percen tages of Asian s an d African Am erican s) an d on ly approxim ately 20% of th ose wh o are positive will develop th is disorder. The first-line treatm ent of SSs is with NSAIDs. Th ere is som e evidence, prim arily anecdotal, th at indom eth acin is the m ost effective of the com m only used NSAIDs, especially wh en given at a dose of 150 m g/ d. Patien ts sh ould be en couraged to rem ain active an d to routin ely perform stretchin g exercises to m ain tain chest expansion , cervical exten sion , an d lum bar flexion . Sulfasalazin e is typically a slow-actin g antirheum atic drug (SAARD) chosen to con trol symptom s of th is illn ess un respon sive to NSAID. Th is drug is typically begun at 1,000 m g twice daily, with th e m axim um dose bein g a total of 4 g/ d. Sulfasalazin e h as been sh own to be effective for con trollin g periph eral polyarticular synovitis in ankylosing spondylitis, but it does not appear to be of use in treating th e axial involvem ent. Anti–TNF-α m edication s are extrem ely effective in th e treatm en t of an kylosin g spon dylitis. Both in flixim ab, a

Figure 7.5 Lateral radiograph of the lumbar spine in ankylosing

spondylitis with “shiny corners” or Romanus lesions (large arrows) due to marginal erosions of vertebral bodies and typical marginal syndesmophytes (small arrows). (Reprinted with permission from Koopman WJ, Moreland LW. Arthritis and Allied Conditions: A Textbook of Rheumatology. 15th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)

ch im eric m onoclonal anti–TNF-α antibody (3 –5 m g/ kg every 6 –8 weeks after an initial saturation phase), and etanercept, a 75-kD TNF-α receptor fusion protein (25 m g subcutaneously two tim es each week), are in curren t use and lead to sign ificant improvem ent in signs and symptom s.

Reactive Arthritis Reactive arthritis (form erly Reiter disease) is classically described by the clin ical triad of arth ritis, urethritis, an d conjun ctivitis. Sin ce th e in itial description , it h as becom e clear that there are several variation s on this them e, with som e individuals havin g only two of th ree m anifestations (i.e., incomplete reactive arthritis), and others havin g colitis in stead of ureth ritis. This syndrom e typically develops in a gen etically susceptible h ost followin g in fection of th e gen itourinary or GI tract with organism s such as Chlamydia, Salmonella, Shigella, Yersinia, or Campylobacter; hence the term reactive arth ritis. Th e arthritis that occurs in reactive arth ritis is typically asym m etric an d oligoarticular, with a predilection for th e large joints of the lower extrem ities. Occasionally, the synovial fluid cell coun ts in th is disorder can be very h igh , in


the range n orm ally only seen in septic arthritis. In addition to th e join t in volvem en t, in flam m ation of ten din ous in sertion in to bone is com m on, such as the Ach illes tendon or plan tar fascia. An oth er ch aracteristic fin din g related to th e presen ce of an en th esopathy is th e fin din g of a “sausage digit,’’ a diffusely swollen toe or fin ger due to the presen ce of both syn ovitis an d en th esopathy. In addition to the peripheral arthritis th at accompanies th e acute illness, som e person s with reactive arth ritis will develop a spon dyloarthropathy sim ilar to ankylosing spondylitis. Th is process is typically less sym m etric than an kylosing spon dylitis an d th e syndesm ophytes are usually larger. O th er clin ical features are com m on ly seen on in itial presen tation. Urethritis is m ore likely to be sym ptom atic in m en than in wom en, and involvem ent of other portion s of th e urogen ital tract (e.g., cystitis, prostatitis) m ay also occur. Eye disease is m ost com m on ly con jun ctivitis, but uveitis an d iritis m ay also be seen . Th ere are a variety of distin ctive m ucocutan eous features th at can be seen , in cluding stom atitis, keratoderm a blennorrhagica, circinate balan itis, an d n ail ch an ges. In th e patien t wh o presen ts with th e classic triad of fin dings, the diagn osis is straightforward. With atypical presen tation s, oth er diagn osis m ust be considered in cludin g gonococcal arth ritis, Lym e disease, rheum atic fever, and crystal-induced arthropath ies. The sim ilarities and differen ces between reactive arth ritis an d gon ococcal arth ritis are particularly important. Just as with th e other SSs, NSAIDs are the treatm ent of ch oice, an d in dom eth acin is th e drug m ost frequen tly used. COX-2 in h ibitors such as celecoxib are equally effective as conventional NSAIDs. Anecdotal eviden ce suggests th at th e acute ph ase of th is illn ess is less respon sive to system ic corticosteroids th an oth er types of in flam m atory arth ritis, but topical corticosteroids m ay be h elpful for extraarticular features. Because of the infectious triggers of th is illn ess, an tibiotics m ay be appropriate in cases wh ere active in fection is eviden t. Th ere is n o eviden ce to justify prolon ged an tibiotic treatm en t beyon d th is in dication. Som e patients with reactive arthritis will have an acute self-lim ited course, but m any will develop chron ic sym ptom s. Th ese patien ts with ch ron ic disease m ay ben efit from the addition of sulfasalazine. As in ankylosing spondylitis, however, sulfasalazin e is effective only for th e periph eral join t in volvem en t in reactive arth ritis, n ot for axial disease (e.g., sacroiliitis). Th e biological an ti–TNF-α inflixim ab and etanercept have a dram atic effect in reactive arth ritis, and their use sh ould be strongly con sidered in severe cases, particularly with axial in volvem en t.

Psoriatic Arthritis Psoriatic arthritis shares m any features with reactive arth ritis, and in som e instances, these two conditions are indistinguishable. The presence of psoriasis is n ecessary for th e diagn osis of psoriatic arth ritis (alth ough in som e in stan ces, the arthritis antedates th e rash ). Only approxim ately 5% of

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in dividuals with psoriasis develop psoriatic arth ritis. Axial skeleton involvem ent and extraarticular features are sim ilar in psoriatic arth ritis an d reactive arth ritis. On e distin ctive feature of psoriatic arthritis is m ore exten sive involvem ent of th e DIP join ts an d th e relation sh ip between th is feature an d n ail pittin g. O n ly approxim ately 20% of person s with psoriasis h ave nail pittin g, but 80% of persons with psoriatic arth ritis h ave n ail pittin g. O th er un usual articular features seen in som e patients with psoriatic arthritis are resorption of th e tufts of th e distal ph alan ges, periph eral join t an kylosis, an d ch aracteristic “pen cil-in -cup’’deform ities.

Enteropathic Arthritis Enteropathic arthritis is th e term com m on ly used to describe th e arth ritides associated with in flam m atory bowel diseases. Th e two m ain form s of en teropath ic arth ritis are: (1) acute episodes of peripheral oligoarticular arth ritis that resem ble reactive arth ritis and are typically associated with flares of th e colitis, an d (2) an axial spon dyloarthropathy th at is closely related to HLA-B27 positivity an d follows a slow, in dolent course that is largely independent of th e bowel disease.

Crystal-Induced Arthropathies Th ere are th ree types of crystal-in duced arth ropath ies th at will be discussed: (1) gout, (2) calcium pyroph osph ate deposition disease (CPDD), an d (3) hydroxyapatite deposition disease (HADD). It is im portan t to recogn ize th at n early any crystallin e or particular substan ce th at can som eh ow be introduced into the joint or soft tissues (e.g., injected steroid, fragm ents from prostheses, plant th orns) can lead to a localized in flam m atory respon se.

Gout Alth ough “gout’’ refers to th e disease process th at occurs wh en m on osodium urate crystals deposit in various tissues in th e body, on ly th e articular m anifestations will be emph asized. Th e serum uric acid con cen tration prim arily determ in es wh eth er m on osodium urate crystals will deposit in tissues. Purin e m etabolism is largely gen etically determ in ed, but m ale gen der, in creased age, in creased body weigh t, h igh -purin e diet, diabetes, hyperten sion , alcoh ol, and other drugs (e.g., diuretics, cyclosporin e) will raise serum concentration of uric acid. The higher th e serum uric acid con cen tration , th e m ore likely an in dividual will develop gout. It is importan t to recogn ize th at on ly a sm all percen tage of hyperuricem ic in dividuals ever develop gout. Rh eum atic features of gout include som e com bin ation of acute attacks of m on oarticular or polyarticular arth ritis and m ore indolent changes caused by accum ulation of uric acid crystals (toph i). Th e first m etatarsoph alan geal (MTP) joint of the foot is the m ost com m only involved join t durin g a first attack of gout. Oth er periph eral join ts in the lower extrem ity (e.g., other MTP joints, m id foot, an kle, an d knee) are next m ost com m on ly involved, followed

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by peripheral join ts in the hand (e.g., DIP, PIP, MCP, and wrist). The predilection for periph eral join ts farthest from the body core is likely due to temperature. Uric acid solubility decreases con siderably as tem perature decreases, an d thus in the setting of a high serum (and thus tissue) uric acid level, crystal form ation an d deposition occur in th ese cooler areas of the body. For this sam e reason , acute gout is rarely seen in th e axial skeleton . Th is temperature-related decrease in solubility m ay also explain why acute gout attacks frequen tly occur at 2:00 amo r 3:00 amin th e m orn in g, abruptly awaken in g an in dividual from sleep. Durin g th is period, a person ’s core body tem perature falls sligh tly because of diurnal changes, and the inactivity of the extrem ity also con tributes to decreased blood flow an d cooler periph eral tem peratures. An acute gout attack will usually begin as a m on oarticular process, wh ich m ay becom e polyarticular with ch ron icity. Men are m uch m ore likely to be affected th an wom en , largely because at any given age, m en h ave h igh er serum uric acid levels. Postm en opausal wom en m ay develop gout, but even th en th is usually occurs because of oth er risk factors (e.g., alcoh ol or m edication use). Durin g an acute attack, a person m ay be febrile, an d th ere is typically an acute in flam m atory respon se eviden t over th e in volved region . Th is in flam m atory respon se is so pron oun ced th at it is com m on for the skin overlying an attack to desquam ate after th e attack h as subsided. Th e acute in flam m atory response can also resem ble cellulitis, especially wh en it occurs in the m id or hind foot or in the dorsum of the wrist. In addition to articular in volvem en t an d soft tissue in flam m ation , an acute bursitis can som etim es occur, especially in th e olecran on region . When a 50-year-old m an presen ts with an acute on set of MTP join t arth ritis, th e diagn osis of gout is straigh tforward. In m any settin gs, oth er clin ical in form ation is n ecessary to establish th e diagn osis. Th e presen ce of toph i is h elpful. Toph i m ay occur in various location s in th e body, in cludin g the helix of the ear, fin gers, or olecranon region. Laboratory testin g is n ot typically useful. Most people with gout will have an elevated uric acid level durin g an acute attack, but som e will not. Many persons will exh ibit leukocytosis or elevation s in in flam m atory in dices, but th ese will n ot h elp differen tiate th e patien t with gout from th ose with oth er types of in flam m atory or septic arth ritis. Radiograph s durin g an acute attack will typically be n orm al or will reveal on ly soft tissue swellin g; with ch ron ic toph aceous disease, radiographs will show evidence of sclerotic m arginal erosion s, typically with preservation of the join t space un til late in th e disease. The detection of m onosodium urate crystals in th e join t fluid is the m ost definitive way to establish the diagnosis of gout. Uric acid crystals are th in , n eedle-sh aped crystals that are approxim ately th e sam e length as a leukocyte and, in fact, m ay be seen in side leukocytes. Un der a polarizin g m icroscope, th e crystals will appear brigh t yellow an d blue, depen din g on th e axis of polarization . Th is is in con trast

to calcium pyrophosphate dihydrate crystals that are pleom orphic in both size and sh ape, are less inten sely birefringen t, an d th us appear pale yellow an d blue. Th e m an agem en t of gout can be divided in to treatm en t of th e acute attack an d prophylaxis again st future attacks. Th e goal in treatin g th e acute attack is to in h ibit th e ability of WBCs to phagocytize the crystals. Th e m ost effective drugs in th is settin g are NSAIDs, an d in dom eth acin is a preferred agent because of the rapid onset of action and potent anti-inflam m atory properties. Any other NSAID, including COX-2 inh ibitors, can also be used, but those with a rapid on set of action are preferred. Colch icin e can also be h elpful durin g an acute attack of gout, alth ough th e GI in toleran ce of th is m edication frequen tly lim its th e effectiven ess. Classically, the patien t is in structed to take 0.6 m g tablet on ce h ourly un til th e attack subsides, un til side effects occur, or un til a total of 10 tablets are taken . Colch icin e, an d to a lesser exten t NSAIDs, is m uch m ore effective when treatm ent is begun rapidly. The reason for this is likely that these anti-inflam m atory regim ens (especially colchicin e) act in part by in h ibitin g ch em otaxis of leukocytes to th e join t, and once this has occurred, th ese agents are m uch less effective. In person s with con train dication s to colch icin e (renal or hepatic impairm ent) or NSAIDs, corticosteroids can be effectively used to treat acute gout attacks. Th ese can be adm in istered in tra-articularly, or system ically, if th ere is m onoarticular involvem ent. When these are given system ically, th e person typically needs to receive treatm ent for several days to avoid a rebound effect (alternatively, a single intram uscular dose of a depot form of corticosteroids can be given ). Wh en person s h ave frequen t attacks of gout, or wh en th ere is eviden ce of toph aceous (or extraarticular) disease, th erapy directed toward lowerin g serum uric acid level sh ould be in itiated. A low purin e diet, or avoiding alcohol use, is som etim es all th at is n ecessary to lower serum uric acid level. If behavioral m odifications are ineffective, then eith er uricosuric drugs or allopurin ol can be used. Th ese drugs sh ould n ot be used in th e settin g of an acute attack, as this can paradoxically precipitate a worsening of th e attack. Probenecid is the m ost com m only used uricosuric drug, an d it can be started at 500 m g/ d an d in creased to 2 g/ d. This drug is effective only in persons with relatively n orm al ren al fun ction ; it sh ould n ot be used in th ose with a h istory of n eph rolith iasis, an d patien ts m ust be coun seled to m ain tain a h igh fluid in take. Allopurinol is a drug th at in h ibits th e en zym e xan th in e oxidase, th us in h ibitin g th e production of uric acid. It can be used as an altern ative for uricosuric treatm ent, e.g., in patients with impaired ren al fun ction or n eph rolith iasis. Allopurin ol can be given begin n in g at doses ran gin g from 100 m g (in th e elderly or th ose with im paired ren al fun ction ) to 300 m g on ce daily. Th e prin cipal con cern with th is drug is hypersen sitivity reaction, so patients m ust be warn ed to stop this m edication im m ediately if th ey develop a rash or pruritus. Approxim ately 5% of in dividuals taking allopurin ol will develop


a pruritic m aculopapular rash th at resolves wh en th e m edication is stopped. However, a sm all percentage of th ese patien ts will go on to develop a serious an d som etim es fatal hypersen sitivity reaction rem in iscent of a Steven s–John son reaction. Curren tly, th ere are n o adequate altern atives for th ose patien ts wh o fail to m ain tain n orm al serum levels of uric acid under treatm ent with uricosuric m edication and/or allopurinol (or for patients in tolerant for these drugs). A num ber of novel m edications are, however, un der developm en t, including the xanthine oxidase inhibitor febuxostat an d the en zym e–drug uricase, wh ich catalyzes con version of uric acid to th e m ore soluble com poun d allan toin . Rasburicase, a recom bin an t form of uricase, curren tly in use for the prevention of tum or lysis syndrom e in h em atological m align ancies, has also been suggested for short-term therapy in refractory cases of gout. An alternative approach to prophylaxis again st gout attacks is to use a low dose of colch icine (e.g., 0.6 m g twice daily in persons with n orm al ren al an d h epatic fun ction ) or an NSAID ch ron ically.

Calcium Pyrophosphate Deposition Disease CPPD crystals can be deposited in a num ber of articular structures including cartilage, synovium , tendon s, an d ligam ents. In m ost cases, there is n o clear reason why a person has CPPD deposition (i.e., idiopathic), whereas in oth er in stan ces, this occurs as a h ereditary disorder or secon dary to an oth er disease process (Table 7.9). Havin g CPPD is n ot necessarily associated with any disease, as a significan t percen tage of persons with this finding will be asymptom atic. For in stan ce, it is estim ated th at n early 50% of in dividuals have CPPD of the knees by th e tim e th ey reach age 80. In oth er in stan ces, CPPD deposition is associated with disease. Th e disease processes com m on ly seen in association with CPPD in clude episodes of acute or ch ron ic in flam -

TABLE 7.9

CONDITIONS PROBABLY ASSOCIATED WITH CALCIUM PYROPHOSPHATE DIHYDRATE CRYSTAL DEPOSITION Aging Amyloidosis Familiar hypocalciuric hypercalcemia Gout Hemochromatosis Hemosiderosis Hyperparathyroidism Hypomagnesemia Hypophosphatasia Hypothyroidism Neuropathic joints Trauma, including surgery (Reprinted with permission from Koopman WJ, Moreland LW. Arthritis and Allied Conditions: A Textbook of Rheumatology. 15th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)

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m atory arthritis (pseudogout) and an accelerated chronic degen erative arth ritis (pseudo-OA). CPDD is diagnosed with a com bin ation of appropriate clin ical fin din gs, radiograph s, an d syn ovial fluid an alysis (Fig. 7.6). The joint distribution of CPDD overlaps som ewh at with sim ilar disorders (e.g., Gout, OA), but th e overall pattern of in volvem en t can be h elpful in differen tiatin g th ese disorders. Th e kn ees, h ips, sym physis pubis, an d wrist are all com m on locations for CPPD deposition, and radiograph s of th ese region s will com m on ly sh ow th e typical ch on drocalcin osis (i.e., calcification of cartilage). In th e kn ee, ch on drocalcin osis m ay be seen in eith er th e tibiofem oral joint or the patellofem oral joint, with th e latter som etim es being preferentially involved. An other clin ical clue to th e presen ce of CPPD is m ore aggressive destruction of th e join t th an would oth erwise be expected in OA. Syn ovial fluid analysis identifying the characteristic rod-sh aped (an d pleom orph ic) crystals of CPPD is h elpful. Th e treatm en t of CPDD depen ds som ewh at on th e m ode of presen tation . If CPDD is secon dary to a m etabolic disorder, th en th is obviously sh ould be addressed. If CPPD presen ts as pseudogout, th e treatm en t is very sim ilar to th at of gout n oted earlier. Both NSAIDs an d corticosteroids can be used to m an age acute attacks, an d colch icin e is even som ewhat efficacious, although less so than for gout. Both NSAIDs an d colch icin e can be used to prophylax again st acute attacks of pseudogout and for th e pseudo-OA presentation.

Hydroxyapatite Deposition Disease Hydroxyapatite m ay be deposited in soft tissues, periarticular structures, or join ts. As with oth er crystal deposition syn drom es, hydroxyapatite deposition m ay either occur as an asymptom atic fin ding or be associated with disease. Soft tissue calcification usually occurs as a result of illnesses such as scleroderm a, derm atomyositis, and ch ron ic renal insufficien cy. In som e in stances where the calcification is exten sive an d causes troublesom e symptom s, surgical in terven tion is n ecessary. Much m ore com m on ly, hydroxyapatite m ay be deposited in th e periarticular tissues. Th is usually occurs at ten don in sertion s, especially in th e sh oulder, h an ds, h ip, an d kn ee. Wh en sym ptom atic, th is can be treated with NSAIDs or corticosteroid injections, although th e use of crystallin e steroid preparation s m ay in som e in stan ces exacerbate th e problem . HADD involvin g the joints is uncom m on. McCarty and colleagues coined th e term “Milwaukee sh oulder’’ to describe an aggressive degenerative process affectin g the en tire shoulder region, prim arily affecting older wom en. Asim ilar process m ay un com m only affect oth er joints.

Systemic Lupus Erythematosus SLE is the prototypic system ic autoim m une disorder. A system ic respon se by th e body again st various self-an tigen s

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B A

C Figure 7.6 (A) Weakly birefringent monoclinic and triclinic calcium pyrophosphate dihydrate disease (CPPD) microcrystals in synovial fluid removed from a chronically symptomatic knee (polarized light, original magnification 1,250). (B) Phagocytosed crystal (arrow) in a polymorphonuclear leukocyte (phase contrast, original magnification 1,250). (C) Anteroposterior radiograph of the knee, showing typical punctate and linear deposits of CPPD in the menisci and articular hyaline cartilage. (Reprinted with permission from Koopman WJ, Moreland LW. Arthritis and Allied Conditions: A Textbook of Rheumatology. 15th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)

leads to in flam m ation , im m un e complex deposition , an d dam age to blood vessels th rough out th e body. Wom en are affected approxim ately five tim es m ore com m on ly th an m en , an d th e peak in ciden ce is in th e th ird an d fourth decade of life. SLE can affect n early any organ or tissue in th e body. Table 7.10 lists the frequen cy of clin ical symptom s, laboratory findings, and diagnostic certain ty in this disorder. Th e m usculoskeletal features bear special emph asis, because these are th e m anifestation s that m ay bring the patien t to an orth opaedist. Nearly all patien ts with th is illn ess even tually h ave eith er arth ralgias or arth ritis. Th e m ain difference from RA or oth er types of inflam m atory arth ritis is that there is little synovitis or joint destruction seen in SLE, alth ough th e join ts m ay be very pain ful. Som e patien ts with SLE develop uln ar deviation of th e fin gers, swan -n eck deform ities, an d oth er ch an ges th at appear very sim ilar to th ose seen in RA. O n exam in ation , however, these deform ities are all reducible, and this en tity h as been term ed “Jacoud arth ropathy.’’ Th is seem s to occur because of ten don laxity rath er th an destruction of

TABLE 7.10

PRESENTING AND CUMULATIVE SYMPTOMS/ SIGNS OF SYSTEMIC LUPUS ERYTHEMATOSUS Symptom/Sign Malar (butterfly) rash Discoid lupus Photosensitivity Arthritis Proteinuria Seizures Psychosis Pericarditis Pleurisy Leukopenia Thrombocytopenia

Percentage with Manifestation

Cumulative Percentage

30 14 29 40 21 4 2 6 16 18 9

56 27 54 70 53 10 5 18 38 46 20

(Reprinted with permission from Koopman WJ, Moreland LW. Arthritis and Allied Conditions: A Textbook of Rheumatology. 15th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)


join ts, an d radiograph s will reveal n orm al join ts. An oth er orth opaedic problem en coun tered relatively frequen tly in SLE is avascular n ecrosis (AVN). Corticosteroid th erapy is probably the m ajor reason for this complication , although AVN has been noted in SLE patients who were not treated with steroids (especially th ose with a positive an ticardiolipin antibody). Th e diagn osis of SLE is based on a com bin ation of clin ical and laboratory features. The ACR diagnostic criteria for SLE are helpful in th is settin g (Table 7.11). Patien ts wh o have four or m ore of these features are likely to h ave SLE. Th e ANA elem en t of th e criteria is particularly importan t, because n early all patien ts with SLE will h ave a positive ANA. Th e treatm en t of SLE is based on th e symptom s an d th e site of involvem ent. Generally, skin an d m usculoskeletal in volvem ent is treated non aggressively with NSAIDs, topical corticosteroids, and/ or hydroxychloroquine. Hem atologic involvem ent, serositis, and severe constitutional symptom s are usually m an aged with corticosteroids, typically with “steroid-sparing’’ drugs (e.g., azathioprin e, m ethotrexate, hydroxych loroquin e) given con curren tly to m in im ize th e long-term complications of the steroids. Renal and central nervous system involvem ent is treated very aggressively, in m any instances with both corticosteroids and cytotoxic drugs such as cycloph osph am ide an d cyclosporin e. Mycoph enolate m ofetil, a drug widely used to preven t rejection of allografts, is currently used in som e cases as a less toxic altern ative to cycloph osph am ide in lupus n eph ritis.

Polymyalgia Rheumatica Polym yalgia rheum atica (PMR) is a com m on disorder occurring alm ost exclusively in persons older than 50 years an d ch aracterized by stiffness and pain in the proxim al m uscles. The on set m ay be abrupt or in dolent. Patients will h ave prom in en t “gellin g’’ wh en ever th ey are in active for prolon ged periods. In som e persons, th ere is swelling an d/or synovitis of the hands associated with this condition. In a subset of individuals, PMR coexists with tem poral arteritis, wh ich can be associated with visual symptom s, h eadach es, jaw claudication , an d alopecia. Patien ts with th ese symptom s or with temporal artery ten dern ess on palpation sh ould h ave a tem poral artery biopsy(s) to determ in e wh eth er temporal arteritis is presen t because m ore aggressive treatm ent regim ens are used for th is subset of patien ts. Doppler exam in ation of th e tem poral arteries is a useful diagn ostic adjun ct. In th e appropriate clin ical settin g, th e diagn osis of PMR is con firm ed by findin g a m arkedly elevated ESR. Other diagn oses th at sh ould be con sidered are fibromyalgia an d hypothyroidism . An oth er diagn ostic test is treatm en t with interm ediate doses of corticosteroids, usually 20 m g of predn ison e per day for several weeks with a rapid taper to 5 to 10 m g/ d. In patien ts wh o do n ot respon d rapidly an d completely to corticosteroids, the diagnosis should be

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TABLE 7.11

THE 1997 REVISED AMERICAN COLLEGE OF RHEUMATOLOGY CRITERIA FOR SYSTEMIC LUPUS ERYTHEMATOSUS 1. Malar rash: Fixed malar erythema, flat or raised 2. Discoid rash: Erythematous raised patches with keratotic scaling and follicular plugging; atrophic scarring may occur in older lesions 3. Photosensitivity: Skin rash as an unusual reaction to sunlight, by patient history or physician observation 4. Oral ulcers: Oral or nasopharyngeal ulcers, usually painless, observed by physician 5. Arthritis: Nonerosive arthritis involving two or more peripheral joints, characterized by tenderness, swelling, or effusion 6. Serositis a. Pleuritis (convincing history of pleuritic pain or rub heard by physician or evidence of pleural effusion) OR b. Pericarditis (documented by ECG or rub or evidence of pericardial effusion) 7. Renal disorder a. Persistent proteinuria > 0.5 g/d or > 3+ OR b. Cellular casts of any type 8. Neurologic disorder a. Seizures (in the absence of other causes) b. Psychosis (in the absence of other causes) 9. Hematologic disorders a. Hemolytic anemia b. Leukopenia (< 4,000/mm3 on two or more occasions) c. Lymphopenia (< 1,500/mm3 on two or more occasions) d. Thrombocytopenia (< 100,000/mm3 in the absence of offending drugs) 10. Immunologic disorder a. Anti-dsDNA OR b. Anti-Smith (anti-Sm) OR c. Positive finding of antiphospholipid antibodies based on i. An abnormal serum level of IgG or IgM anticardiolipin antibodies, OR ii. A positive test result for lupus anticoagulant using a standard method, OR iii. A false-positive serologic test for syphilis known to be positive for ≥ 6 mo and confirmed by Treponema pallidum immobilization or fluorescent treponemal antibody absorption test 11. Antinuclear antibody: An abnormal titer of ANA by immunofluorescence or an equivalent assay at any time and in the absence of drugs known to be associated with “drug-induced lupus syndrome” ANA, antinuclear antibody; dsDNA, double-stranded deoxyribonucleic acid; ECG, electrocardiogram. (Reprinted with permission from Koopman WJ, Moreland LW. Arthritis and Allied Conditions: A Textbook of Rheumatology. 15th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)

question ed. Typically, patien ts will n eed to stay on corticosteroids at least 1 to 2 years an d som etim es m uch lon ger.

Infectious Arthritis Bacterial Agents Septic arthritis from com m on pathogen s is covered in detail in in fection ch apter of th is book. Such processes usually

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occur in an im m un ocom prom ised h ost or as th e result of bacterem ia or direct bacterial in oculation of a join t. But there are a few types of infectious (or postinfectious arthritis) th at can occur with out such risk factors. Rh eum atic fever and gonococcal infection s are specific examples. The arthritis associated with rh eum atic fever does n ot occur because th e join t is in fected with th e causative organ ism but rath er because of an im m un ologic reaction to th e group A streptococcus organ ism . For reason s th at are un clear, on ly ph aryn geal in fection s with th is organ ism are associated with rh eum atic fever. Th e classic m an ifestation s of rh eum atic fever are described by th e Jon es criteria an d m ay follow the pharyngitis by several days to weeks. Th e m ajor clin ical fin din gs in clude polyarth ritis, carditis, ch orea, eryth em a m argin atum , an d subcutaneous nodules; m in or findings include fever, arthralgia, an d previous rh eum atic fever. Th e arth ritis associated with rheum atic fever is unique in that this is one of the few arth ritides th at is truly m igratory, th at is, th e arth ritis m oves from one joint to the next. Large peripheral joints are m ost com m only involved. The onset is typically abrupt and severe, with coexisten ce of m yalgia an d fever. Alth ough th is disorder is un com m on in adults, th e articular features m ay predom in ate th e clin ical picture, with an absen ce of extraarticular features. Also, in adults th e arth ritis m ay be m ore “additive’’ th an m igratory an d be less respon sive to salicylates or NSAIDs than it is in children . Gonococcal arth ritis can follow a gon ococcal in fection in volvin g th e ureth ra, cervix, ph aryn x, or rectum . Typically, an in dividual will in itially experien ce several days of fevers, ch ills, m ultiple skin lesion s, an d polyarth ralgias or ten osyn ovitis. If un treated in th is stage, it will typically progress to in volve just a few join ts or ten don s. In dividuals with such a clin ical picture should be started im m ediately on an antibiotic such as ceftriaxon e an d should have cultures taken of all orifices, any affected syn ovium , an d any skin lesion s. Th ese cultures sh ould be plated at the bedside on Thayer–Martin m edia or ch ocolate agar. Person s in th e early ph ase are m ost likely to h ave positive blood cultures, wh ereas th ose in th e later ph ase are m ore likely to h ave positive syn ovial or skin lesion cultures.

Nonbacterial Agents Less com m only, join ts (or soft tissue structures) can becom e infected with nonbacterial agents such as tuberculosis or fun gi. With th e exception of tuberculosis, wh ich can cause a septic arthritis in persons with norm al im m une function, m ost persons who have joint infection s with these types of organ ism s h ave an un derlyin g defect in im m un e function. Viral Agents Nearly all viral agen ts can lead to th e developm en t of a postviral arth ritis in a sm all percen tage of affected in dividuals. It appears as th ough th e m ost com m on cause of postin fectious arth ritis in person s wh o seek m edical atten -

tion is that associated with parvovirus B19 infections. This virus is com m on in children, leadin g to Fifth disease, or eryth em a in fectiosum . In affected ch ildren , cutan eous m an ifestation s predom inate, with the characteristic “slapped cheeks’’ appearance, as well as a serpiginous rash affecting the torso or extrem ities. Adults who develop this infection have less prom in ent cutaneous features and m ore prom in en t articular features. Th e articular features closely resem ble th ose of RA, so closely in fact th at up to 50% of th ese person s will m eet criteria for th e diagn osis of RA. Th e diagn ostic test of ch oice is an IgM titer for parvovirus B19, which will be positive at th e tim e join t symptom s begin and last approxim ately 2 m on th s. Although this illness typically has a self-lim ited course and is n ot associated with join t dam age, th ese patien ts are quite un com fortable an d debilitated an d m ay n eed treatm en t with NSAIDs or even low-dose steroids for several m on th s. Rubella, hepatitis B, and hepatitis C are additional examples of viral agents capable of causin g arthralgia an d arth ritis. HIV infection is associated with a wide range of m usculoskeletal m anifestations. These patients suffer from a h igh prevalen ce of seron egative form s of arth ritis in cluding psoriatic arthritis an d reactive arthritis as well as from a periph eral arth ritis sim ilar to oth er form s of viral arth ritis.

Lyme Disease Lym e disease is a m ultisystem illn ess caused by th e tickborn e spiroch ete Borrelia burgdorferi. Th e characteristic lesion develops within days to weeks of a bite by an infected tick. This lesion is term ed erythema chronicum migrans an d evolves into an annular lesion with a central clearing. Once the organism becom es hem atogen ously spread, a variety of m anifestations can occur, in cluding sim ilar an nular lesion s in other regions of the body, fever, lym ph aden opathy, myalgia, arth ralgia, an d fatigue. Th is early ph ase, even if treated, typically evolves in to an in term ediate phase, characterized by arth ritis, cardiac, an d/ or neurological in volvem en t. Th e true arth ritis of Lym e disease (in contrast to the arthralgia an d myalgias that occur early) develops m on th s after th e exposure. Th is will usually begin as interm ittent episodes of inflam m atory arthritis in volving the large joints and, over years, will progress to becom e a con stan t m on oarticular or oligoarticular arth ritis involving large joints. The knees are frequently involved, and in severe cases, joint erosion s an d dam age m ay occur.

PHARMACOLOGIC THERAPY Overview Th e basic prin ciple of ph arm acologic th erapy for any disorder is to use th e least toxic an d least expen sive m edication for the illness being treated. This is particularly true for the rheum atic diseases, where there are several relatively


nontoxic and inexpensive drugs (e.g., acetam inoph en , over-th e-coun ter [O TC] NSAIDs) available th at are effective for m any conditions. Two important factors need to be considered when ch oosing th e m ost appropriate pharm acologic th erapy for a patient with a rh eum atic problem . Th e first is whether the problem is local or system ic in n ature, an d th e secon d is wh eth er th e process is in flam m atory or n on in flam m atory. For local problem s, topical an algesics or in jection s m ay be con sidered in stead of system ic therapy. For noninflam m atory con dition s, an algesics such as acetam in oph en can be con sidered instead of NSAIDs or other potentially m ore toxic regim en s.

Analgesics Acetam inophen is an effective an d safe an algesic for m any noninflam m atory rheum atic conditions. For example, in OA, several ran dom ized con trolled trials h ave suggested that this compound is as effective as either the O TC or prescription stren gth of NSAIDs. Th e prin cipal toxicity of acetam in ophen is hepatic, although th is typically occurs in person s eith er con sum in g con curren t h epatotoxin s (especially alcoh ol) or exceedin g the recom m ended dose. Tram adol is a m oderate-strength analgesic th at can be considered in persons who require an an algesic but do not respon d to acetam in oph en . Fin ally, n arcotics can be effective in both th e sh ort- and lon g-term m anagem ent of pain, although both tolerance and addiction are potential problem s. NSAIDs Th e NSAIDs represen t on e of th e m ost com m on ly prescribed classes of drugs. Aspirin is the origin al an d prototypical NSAID. Th ese drugs all act largely by in h ibitin g cyclooxygenase, the enzym e that transform s arachidonic acid into prostaglandins, prostacyclin, and throm boxane; the clinical relevan ce of the effects of NSAIDs on lipid m etabolism , granulocyte m igration , and bradykin in synthesis is less well understood. Although there are n ow dozen s of NSAIDs available, th e n ewer drugs in th is class are not necessarily m ore effective than older ones or even aspirin, but they are generally better tolerated (Table 7.12). Th e m ain differen ces am on g NSAIDs are (1) h alf-life, (2) relative poten cy at th e prescribed dose, (3) tolerability, an d (4) cost. When con siderin g th e appropriate NSAID, several factors sh ould be con sidered in regard to th e m edication ’s half-life. If a drug is to be used to treat an acute in flam m atory con dition s (e.g., an attack of gout), a drug with a sh ort half-life and rapid onset of action, such as indom ethacin, sh ould be considered. On th e oth er hand, when prescribin g NSAIDs for elderly patien ts, wh ich com prise th e subset of NSAID users th at develop n early all of th e m ajor GI bleeds an d death from this class of drugs, compounds with long half-lives sh ould generally be avoided.

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With respect to potency, there again are several factors to con sider. Th e first is th at for m ost NSAIDs, th e recom m en ded prescription dose h as an an ti-in flam m atory effect, an d on e-h alf to on e-th ird of th at dose (th e dose th at is typically available O TC) h as an an algesic effect. On e of th e m ost importan t prin ciples in prescribin g th is class of drugs is to use th e lowest dose possible, because th e gastric an d ren al side effects of th ese compoun ds are directly related to th e ability of th ese compoun ds to block cyclooxygen ase. Th us, if on e chooses to treat a n on in flam m atory con dition such as OA with this class of drugs, a dose lower than the typical prescription dose usually will be just as efficacious an d safer. It is difficult to directly compare th e relative poten cy of on e NSAID versus an oth er, because th ere are n o establish ed in vitro assays th at predict th e relative poten cy of th is class of com poun ds. But gen erally, NSAIDs th at h ave been m arketed m ore recen tly are tested an d released at relatively less poten t doses th an older compoun ds. Tolerability is an important issue with respect to NSAIDs an d sh ould n ot be con fused with toxicity. Th ere is a gen eral m iscon ception th at wh en a person takes an NSAID an d develops dyspepsia, h eartburn , or oth er GI side effects, th is person m ay be developin g peptic ulcer disease (PUD). In n um erable studies h ave dem on strated th at th ere is little relation sh ip between th e symptoms (i.e., tolerability) th at person s develop wh en th ey con sum e an NSAID an d th e developm en t of PUD. Most person s wh o develop a m ajor GI bleed from NSAIDs have no symptom s that antedate the bleed, an d in fact symptomatic person s takin g NSAIDs are actually less likely to have a peptic ulcer than asymptom atic person s. Th e reason for th is appears to be th at th e tolerability of an NSAID m ay be in fluen ced by local factors such as acidity in th e GI tract (an d th us is improved by takin g an tacids or H2 blockers, or by en teric coatin g of tablets), wh ereas th e developm ent of PUD is due to a system ic effect of th e NSAID on the production of prostaglandin s in the stom ach. For th is reason , NSAIDs that are adm inistered paren terally are just as likely to cause PUD as orally adm in istered compoun ds. Misoprostol, a prostaglan din an alog, is currently approved as prophylaxis against NSAID-induced gastropathy. COX-2 inhibitors are a class of NSAIDS developed specifically for preven tion of GI side effects. Since cyclooxygen ase 1(COX-1) is the enzym e responsible for m ain tain in g gastric epith elial in tegrity wh ile COX-2 is th e m ajor en zym e in volved in in flam m ation , th eoretically, compared with nonspecific COX-1/ COX-2 inhibitors (tradition al NSAIDs), COX-2 –specific drugs m aintain antiin flam m atory efficacy with out dam agin g th e GI tract (Fig. 7.7). These m edications still m ust be used with caution, h owever, in th e presence of ren al impairm en t an d cardiovascular disorders. In deed, wh ile COX-2 in h ibitors h ave gain ed trem en dous popularity over th e last decade, serious concerns have arisen regardin g th eir adverse cardiovascular profile, leadin g to th e with drawal of on e of th e m ost popular m edication s in th is group, rofecoxib (Vioxx).

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Ankylosing spondylitis, arthralgia, bursitis, gouty arthritis, moderate pain, OA, RA, tendinitis Moderate pain, OA, RA

Sulindac (Clinoril)

Oxaprozin (Daypro)

Diclofenac (Voltaren, Arthrotec)

Arthralgia, mild-moderate pain, miosis inhibition, myalgia, OA, RA Actinic keratoses, allergic conjunctivitis, ankylosing spondylitis, arthralgia, corneal ulcer, dysmenorrhea, headache, keratoconjunctivitis, migraine, mild to moderate pain, myalgia, OA, postoperative ocular inflammation, RA

Flurbiprofen (Ansaid)

Ankylosing spondylitis, arthralgia, bursitis, dental pain, dysmenorrhea, fever, gout arthritis, headache, JRA, mild to moderate pain, myalgia, OA, RA, tendinitis

Salsalate (Disalcid)

Nonselective NSAIDs Naproxen (Naprosen, Anaprox)

Mild to moderate pain OA, RA

Choline magnesium trisalicylate (Trilisate)

Indications and Uses

Arthralgia, dental pain, dysmenorrhea, fever, headache, JRA, migraine, mild pain, myalgia, OA, RA, prevention and treatment of cardiovascular thrombosis Fever, JRA, mild to moderate pain, OA, RA

Salicylates Aspirin

Drug (Trade Names)

Tablets

Tablets (combination with misoprostol) Ophthalmic solution Topical solution Tablets

Tablets

Tablets Ophthalmic solution

Tablet Extended-release tablet Suspension

Capsules Tablets

Solution Tablets

Numerous

Formulations

600–1200 mg q.d.

150–200 mg b.i.d.

50–100 mg b.i.d.; maximum 225 mg/d

50–100 mg b.i.d. or t.i.d.; maximum 300 mg/d

500–1,000 mg b.i.d.

2–4 g daily divided dose

3 g/d in divided doses

Variable, depending on indication; maximum (adults) 2.4–5.4 g/d in four or more divided doses

Daily Dose

Hepatic

Hepatic

Hepatic

Hepatic

Hepatic and renal

Hepatic and renal

Hepatic and renal

Hepatic and renal

Metabolism

36–92 h

8–16 h

1–2 h

3–9 h

10–20 h

1h

Low dose 2–3 h; high dose 15–30 h

Acetylsalicylic acid 15–30 min; salicylate 2–30 h

Half-life

CHARACTERISTICS OF CURRENTLY APPROVED NONSTEROIDAL ANTI-INFLAMMATORY DRUGS (NSAIDS)

TABLE 7.12

Nonindicated use in JRA of 10–20 mg/kg/d reported

Diclofenac/misoprostol combination contraindicated in pregnancy because of abortifacient effect of misoprostol Nonindicated use in JRA 2–4 mg/kg/d suggested

Cholestyramine reduced bioavailability of diclofenac

Naproxen may falsely elevate urinary 17-ketosteroid concentrations and interfere with 5-hydroxyindoleacetic acid determination. Discontinue 72 h before testing.

Dosage in children aged > 2 y is 10–15 mg/kg/d in two divided doses.

Serum salicylate levels may need to be monitored at higher doses. Serum salicylate levels may need to be monitored at higher doses.

Dose in children < 37 kg is 50 mg/kg/d

Dose in children body weight < 25 kg is 60–90 mg/kg/d. Serum salicylate levels may need to be monitored at higher doses.

Other Considerations

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Mild to moderate pain, OA, RA

Arthralgia, headache, moderate pain, myalgia, OA, RA

Ankylosing spondylitis, arthralgia, bursitis, gouty arthritis, moderate pain, myalgia, OA, patent ductus arteriosus, RA, severe pain, tendinitis

Arthralgia, dental pain, dysmenorrhea, fever, headache, JRA, migraine, mild to moderate pain, myalgia, OA, RA

Arthralgia, mild to moderate pain, myalgia, OA, RA

Arthralgia, bone pain, dental pain, mild pain, moderate pain, myalgia, OA RA

Arthralgia, dental pain, dysmenorrhea, fever, headache, mild to moderate pain, myalgia, OA, RA

Diflunisal (Dolobid)

Piroxicam (Feldene)

Indomethacin (Indocin)

Ibuprofen (Motrin)

Fenoprofen (Nalfon)

Etodolac (Lodine)

Ketoprofen (Orudis)

75 mg t.i.d. or 50 mg q.i.d.

Extended release tablets Capsules

Extended release capsules Tablets

600–1,200 mg daily

Children: 5–10 mg/kg 300–600 mg t.i.d. to q.i.d.; maximum 3,200 mg/d

Adults: 400–800 mg t.i.d. to q.i.d.

25–50 mg t.i.d. to q.i.d.

20 mg q.d.

500–1,000 mg b.i.d.

Tablets

Tablets Capsules

Numerous

Capsules Extended-release capsules Suspension Suppositories Parenteral

Capsule

Tablets

Hepatic

Hepatic

Enterohepatic recirculation

Hepatic

Hepatic

Hepatic with enterohepatic recirculation Hepatic Some enterohepatic recirculation

Hepatic

1.1–4 h

6–7 h

2.5–3.0 h

(continued )

Increased plasma concentration of ketoprofen when administered with probenecid.

Phenobarbital can decrease plasma concentrations of fenoprofen. Monitor barbiturate levels after initiation or withdrawal of fenoprofen. Elevated free and total triiodothyronine plasma concentrations by some methods

Aspirin can decrease fenoprofen plasma concentrations by 50% and reduce half-life.

Indomethacin augments the hypothalamic—pituitary–adrenal axis response to dexamethasone Possible false-normal results in patients with depressed response Safety demonstrated in children 6 mo of age and older

Prolonged half-life in neonates and premature neonates 2–4 h

Increased serum aminoglycoside concentrations in neonates; monitor aminoglycoside levels closely in all patients

50% increase in acetaminophen plasma concentration following administration of diflunisal Diflunisal is a salicylic acid derivative, association with Reye syndrome not known. Avoid in children Diflunisal may falsely elevate serum salicylate levels Particular caution in high-risk individuals

Biphasic: 1 h initial; 2.6–11.2 h in second phase

50 h

68–138 h in severe renal disease

8–12 h

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Arthralgia, dysmenorrhea, mild to moderate pain, OA, RA

OA

Moderate pain, OA, RA

Arthralgia, JRA, moderate pain, myalgia, OA, RA

Meclofenamate, mefenamic acid (Ponstel)

Meloxicam (Mobic)

Nabumetone (Relafen)

Tolmetin (Tolectin)

Bone pain, dental pain, dysmenorrhea, headache, mild to moderate pain, OA, RA Dysmenorrhea, OA, RA Tablet

Tablet Suspension

Capsules

Tablets Capsules

Tablets

Tablets

Capsule

Parenteral (i.m. or i.v.) Ophthalmic solution

Tablets

Formulations

10 mg q.d.; 20 mg q.d. as needed for dysmenorrhea

12.5–25 mg q.d.; 50 mg q.d. for 5 days for pain

100–200 mg b.i.d.; 400 mg b.i.d. in FAP

1,000 mg q.d.; maximum dose of 2,000 mg q.d. 400 mg t.i.d. to q.i.d.; maximum dose 2,000 mg/d

Mefenamic acid: 250 mg every 6 h for 7 days; maximum 1,250 mg/d 7.5–15 mg q.d.

50–100 mg t.i.d. to q.i.d.; maximum 400 mg/d

10 mg p.o. every 4–6 h; maximum of 40 mg daily for 5 days

30 mg i.m. or i.v. every 6 h; maximum 120 mg/d; do not use for more than 5 days

Daily Dose

Hepatic

Hepatic

Hepatic

Hepatic

Hepatic

Hepatic

Hepatic

Hepatic

Metabolism

8–11 h

17 h

11 h

Biphasic: initial 1–2 h; terminal 5 h

24 h

15–30 h

2h

Biphasic; terminal phase 4–6 h

Half-life

Fluconazole inhibits celecoxib metabolism in the liver. Use lowest celecoxib dose with concomitant fluconazole.

Reduce dose by 50% in setting of moderate liver dysfunction.

False-positive reaction for proteinuria on acid precipitation test; no effect on urine dipstick test for protein.

Dosage in children age 2 y and above 5–7 mg/kg/dose p.o. every 6–8 h.

Cholestyramine may increase clearance meloxicam. No platelet inhibition at indicated doses.

Parenteral ketorolac can enhance the muscle relaxant effect of nondepolarizing skeletal muscle relaxants. Caution with concomitant use. Mefenamic acid may cause false-positive test result for urinary bile.

Elimination half-life of ketorolac is doubled during administration with probenecid. Concomitant use should be avoided.

Other Considerations

b.i.d., twice daily; FAP, familial adenomatous polyposis; i.m., intramuscularly; i.v., intravenously; JRA, juvenile rheumatoid arthritis; OA, osteoarthritis; p.o., by mouth; q.d., daily; RA, rheumatoid arthritis; t.i.d., three times daily.

Valdecoxib (Bextra)

Rofecoxib (Vioxx)

Bone pain, dental pain, dysmenorrhea, FAP, headache, moderate to severe pain, OA, RA

Allergic conjunctivitis, arthralgia, moderate pain, myalgia, ocular pain, ocular pruritus, photophobia, postoperative ocular inflammation

Ketorolac (Toradol)

Selective COX-2 inhibitors Celecoxib (Celebrex)

Indications and Uses

Drug (Trade Names)

(Continued )

TABLE 7.12


Figure 7.7 Prostaglandin synthesis pathway with sites of non-

steroidal anti-inflammatory drug inhibition. (Reprinted with permission from Koopman WJ, Moreland LW. Arthritis and Allied Conditions: A Textbook of Rheumatology. 15th ed. Philadelphia: Lippincott Williams & Wilkins, 2005.)

Adifficult issue in clin ical practice is to decide which patients who are prescribed NSAIDs should also receive prophylaxis again st PUD. It is first importan t to un derstan d which person s are at in creased risk of developin g th is com plication . Th e factors th at place a patien t at h igh er risk of developin g a GI bleed in clude a h istory of PUD, ch ron ic use of an tacids or H2 blockers, cigarette sm okin g, alcoh ol use, an ticoagulan t use, con com itan t corticosteroid th erapy, and being older than 65 years. The m ore of these risk factors persons have, the m ore likely they are to develop a m ajor GI bleed. But arguably, th e m ost im portan t risk factor is being elderly. Alth ough elderly persons taking NSAIDs are only approxim ately 1.5 tim es as likely to develop a GI bleed as a youn ger person , n early all of th e m ortality from NSAID-associated GI bleeds occurs in person s older th an 65 years. Th e reason for th is appears to be th at youn ger person s tolerate GI bleeds better th an th e elderly, wh o com m on ly will develop a m yocardial in farction , stroke, or som e other m ajor m edical event in association with a GI bleed. Th e coagulation effects of NSAIDs are also widely m isun derstood in clin ical practice. Aspirin irreversibly bin ds to cyclooxygen ase, so th at th e in h ibition of platelet fun ction that occurs after con sum in g aspirin lasts until all of the platelets th at were exposed to th e drug die (approxim ately 2 weeks). But all other NSAIDs reversiblybin d to cyclooxygenase, so the an tiplatelet effects of these drugs last only while they are in the circulation (i.e., several h alf-lives). There is no need to stop nonaspirin NSAIDs m ore than a few days before a surgical procedure to avoid th e an tiplatelet effects of th ese drugs. By far, the m ost com m on renal side effect of th e NSAIDs is a reversible decline in ren al function. This alm ost always occurs in persons who have dim inished baseline ren al blood flow, for exam ple, in patien ts with low cardiac output states, ren al artery sten osis, or preexistin g ren al disease.

143

Th e reason for th e selective occurren ce of th is side effect in th ese person s is likely th at vasodilatory prostaglan din s are produced on ly by th e kidn ey as a compen sation for low ren al blood flow. Adm in isterin g th ese m edication s in th is settin g will decrease local prostaglan din syn th esis in th e kidn ey, decrease renal blood flow, and worsen ren al fun ction . In som e in stan ces, th is declin e in ren al function can be perm an ent, so NSAIDs should be prescribed with caution in this settin g. Concom itant use of an gioten sin -con vertin g en zym e in h ibitors m ay exacerbate the reduction in renal function, so extrem e care m ust be exercised wh en prescribin g NSAIDs togeth er with th ese m edication s.

Corticosteroids Because of the poten t an ti-in flam m atory effects of corticosteroids, th ese drugs are useful for th e treatm en t of a n um ber of local an d system ic in flam m atory con ditions. A th orough review of th e m ech an ism (s) of action s of th ese drugs is n ot possible, but th ese drugs likely act by a variety of m ech an ism s, in cludin g in terferen ce with cell adh esion an d m igration in to inflam m atory sites; interruption of cell–cell com m unication; impairm ent of prostaglandin, leukotriene, and neutrophil superoxide production; and impairm ent of antigen opsonization and im m une complex clearan ce. Th e sh ort-term use of system ic corticosteroids is relatively well tolerated, even at higher doses. Un com m on but serious side effects in th is settin g m ay in clude AVN, psych osis or lesser m ood disturban ce, hyperglycem ia, hyperten sion , an d electrolyte disturban ces. In con trast, th e long-term uses of corticosteroids, even at low doses, are associated with a plethora of side effects, including osteoporosis, accelerated ath erosclerosis, in fection s, cataracts, skin chan ges, an d oth ers. Because of this, and because of th e fact th at steroids represen t by far th e m ost effective m edications to bring inflam m atory processes un der rapid con trol, m ost clin ician s attem pt to use h igh doses in itially for sh ort periods, followed by as rapid a taper as possible, eith er with complete discon tin uation or to ch ron ic regim ens (e.g., less than 7.5 m g of prednisone per day or altern ate day dosin g) th at m inim ize toxicity. Another significant problem with chronic steroid usage is suppression of th e hypothalam ic–pituitary–adren al (HPA) axis. This can occur with as little as 1 week of highdose steroid treatm en t an d occurs in n early all people wh o receive ch ron ic corticosteroid treatm en t. Th is is importan t because person s with a suppressed HPA axis n eed to receive exogen ous steroids wh en exposed to stressors, such as undergoing a m ajor surgical procedure. There is n o “correct’’ regim en in th is settin g, but adm in isterin g 100 m g of hydrocortison e paren terally on call to th e operatin g room , and 50 m g every 6 hours for 24 h ours, then 25 m g every 6 hours for an oth er 24 hours, is m ore than sufficient in th is settin g (less aggressive regim en s m ay also be used).

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TABLE 7.13

SLOW-ACTING ANTIRHEUMATIC, DISEASE-MODIFYING, AND CYTOTOXIC DRUGS Drugs

Class

Mechanism of Action

Hydroxychloroquine

Antimalarial

Sulfasalazine Methotrexate Leflunomide Cyclophosphamide, chlorambucil Azathioprine, 6-Mercaptopurine Cyclosporine, Tacrolimus (FK506)

Antimicrobial Antimetabolite Antimetabolite Alkylating cytotoxics Purine analog cytotoxics Calcineurin inhibitors

Sirolimus (rapamycin)

Non–calcineurin-binding macrolide immunoregulator Purine synthesis inhibitor

Interferes with intracellular function dependent on acidic microenvironment Exact mechanism unknown Purine inhibition Pyrimidine inhibition Active metabolites alkylate DNA Inhibit purine synthesis Inhibit calcium-dependent T-cell activation and interleukin-2 (IL-2) production Blocks IL-2– and growth factor–mediated signal transduction Mycophenolic acid inhibits inosine monophosphate dehydrogenase

Mycophenolate mofetil

SAARDs and Disease-Modifying and Cytotoxic Drugs Table 7.13 lists a num ber of SAARDs an d cytotoxic drugs that are used in the m anagem ent of patients with autoim m un e disorders. Th ese m edication s are com m on ly used in a variety of settings, som etim es as sin gle agen ts in less aggressive disease (e.g., hydroxych loroquin e in m ild RA, sulfasalazin e in reactive arth ritis) or as steroid-sparin g drugs (to m in im ize th e usage of lon g-term steroids) in illn esses such as SLE, vasculitis. As noted earlier, the biological m edication s, such as an ti–TNF-α m edication s, are becom in g in creasingly com m on for the treatm ent of a large num ber of rh eum atologic disorders, such as RA, AS, an d oth er SSs. The m ain reason that the practicin g orth opaedist n eeds to be aware of th ese m edication s is because of th eir effects on wound healing and infections (especially perioperative). Alth ough it is com m on ly felt th at m any of th ese drugs (e.g., h igh -dose corticosteroids, m eth otrexate) m ay in crease the rate of perioperative infections, the data to support th is are largely an ecdotal. Non eth eless, m ost clin ician s will attempt to stop m eth otrexate for 1 week prior to, an d

2 weeks after, m ajor surgical procedures. With respect to corticosteroids, th ere is typically an attempt to get the patien t to th e lowest dose possible prior to surgery.

RECOMMENDED READINGS Clauw DJ. Fibromyalgia: update on m echanism s and m anagem ent. J Clin Rheumatol. 2007;13(2):102 –109. Drazen JM. COX-2 inhibitors—a lesson in unexpected problem s. N Engl J Med. 2005;352(11):1131 –1132. Felson DT, Lawren ce RC, Dieppe PA, et al. Osteoarth ritis: n ew in sigh ts, I: th e disease an d its risk factors. Ann Intern Med. 2000;133(8):635 – 646. O’Dell JR. Th erapeutic strategies for rh eum atoid arth ritis. N Engl J Med. 2004;350(25):2591 –2602. Olsen NJ, Stein CM. New drugs for rh eum atoid arth ritis. N Engl J Med. 2004;350(21):2167 –2179. Rahm an A, Isenberg DA. System ic lupus erythem atosus. N Engl J Med. 2008;358(9):929 –939. Rice PA. Gon ococcal arth ritis (dissem in ated gon ococcal in fection ). Infect Dis Clin North Am. 2005;19(4):853 –861. Sch um ach er HR. Crystal-in duced arth ritis: an overview. Am J Med. 1996;100(2A):46S–52S. van Vollenhoven RF. Corticosteroids in rheum atic disease: understan din g th eir effects is key to their use. Postgrad Med. 1998;103(2): 137 –142.

8

Overview of Musculoskeletal Neoplasm s Atu l F. Kam ath

Harish S. Hosalk ar

INTRODUCTION Tum ors of th e m usculoskeletal system m ay present initially with n on specific symptom s, m akin g it h ard to distin guish neoplastic m anifestation s from other com m on disorders. Wh ile bon e an d soft-tissue tum ors are rare, it is critically important that the orthopaedist include these entities in the differential diagnosis to avoid overlooking these poten tial serious con dition s. Th is ch apter presen ts a system atic m eth od for evaluating tum ors of the m usculoskeletal system . It also presents a brief overview of th e distin guish in g ch aracteristics, path ology, an d treatm en t of several of th e m ost com m on en tities.

BONE TUMORS Patient Evaluation In th e evaluation of a patien t with a bon e tum or, th ere are several areas where data can be gathered that impact upon th e differen tial diagn osis. Th ese in clude th e h istory, physical exam in ation , an d review of im agin g studies. Ultim ately, it m ay be determ ined that histologic con firm ation is required at which tim e careful evaluation of lesional tissue will confirm a specific diagnosis. Th e h istory associated with th e presen ce of a m usculoskeletal tum or defin es the clinical context of th e lesion. Age, sex, duration of symptom s, presen ce and quality of pain , h istory of traum a, weigh t loss, sm okin g h istory, an d

Richard D. Lack m an

h istory of prior m align ancy are all im portan t h istorical factors. Critical to th e early diagn osis of a skeletal tum or is an appreciation of th e fact th at th e early symptom s associated with skeletal n eoplasm s m im ic all types of ordinary m usculoskeletal disorders. Any pain th at exten ds beyon d the expected duration associated with a tentative diagnosis sh ould raise the suspicion of an underlying tum or. Night pain is an oth er red flag again leadin g to th e supposition of an occult lesion alth ough m any n on n eoplastic con dition s m ay also cause pain at n igh t. One of the m ost disorien ting parts of a history in a patien t with an occult tum or is a h istory of traum a. Frequen tly, patien ts will experien ce som e m ild traum a to th e affected area an d th en n otice pain th at would probably n ot h ave occurred in th e absen ce of an un derlyin g lesion . Th is is frequently not clear to th e patient however who directly attributes th e local sym ptom s an d fin din gs to th e traum atic even t. Th e h istory related in th is way frequen tly fools a treatin g physician wh o th en follows th e local lesion un til it becom es obvious th at th e true n ature of th e lesion goes well beyond a m inor traum a. An example of this is the story related by a waiter who kicked a kitchen door to open it wh ile carryin g a h eavy tray. Th e door was stuck an d did n ot m ove, resulting in an apparen t calf in jury. When th e pain did n ot resolve, a com partm en t syn drom e was suspected an d it was n ot un til several m on th s later th at tissue was obtain ed wh ich revealed an un derlyin g lym ph om a. Sim ilar is th e h istory of an elderly fem ale on full-dose warfarin for a m ech anical heart valve who bumped her thigh on a kitch en table an d foun d out m on th s later th at th e

146


large an terior th igh m ass was a soft-tissue sarcom a an d n ot a simple h em atom a.

Imaging Plain radiograph s offer detailed in form ation for bon e lesion s, as well as som e potentially im portan t inform ation for soft-tissue lesions. It is estim ated that about 30% to 40% of th e bon e m ust be destroyed before th e ch an ges can be seen in plain radiographs. It is useful to ask th e followin g when evaluating plain radiograph s of bony lesions: Wh ere is th e lesion located in th e bon e? Wh at is th e lesion doin g to th e bon e? How is th e bon e reactin g to th e lesion ? Wh at is th e periosteal respon se? A lesion ’s m argin with adjacen t m edullary bon e m ay suggest an indolent versus an aggressive process. Any lesion that is stable and recognized by the bone as foreign will be “walled off’’ by dense sclerotic bon e, implying a very slow growin g or static lesion . However, lesion s n ot recogn ized as foreign will not gen erate surrounding sclerosis despite bein g presen t for exten ded periods. A ben ign en ch on drom a, for example, elicits no surrounding bone response because it is n ot con sidered “foreign .’’ Multiple myelom a is a m align an t tum or but still elicits n o respon se in th e m arrow, as plasm a cells are a n orm al part of m arrow an d h en ce n ot recogn ized as foreign . Marrow respon se to a lesion is th e m ost sen sitive for ch aracterizin g aggressive lesion s. Marrow surroun din g a lesion m ay dem on strate a geograph ic (e.g., in m ultiple myelom a), m oth-eaten (e.g., in giant cell tum or), or perm eative (e.g., in osteosarcom a) appearan ce based on th e degree an d n ature of th e offen din g lesion . Th e cortex exists as a m ore gross m arker of m align an t dam age to bon e, in cludin g en dosteal scallopin g, cortical th in n in g or expan sion , an d of course gross cortical destruction. The pattern of periosteal reaction itself is also an in dicator of th e biologic activity of a lesion . A lesion m ay elicit n o reaction for one of two reason s: either the tum or is not perm eating the periosteum (e.g., in giant cell tum or) or the periosteum does n ot recogn ize th e tum or cells as foreign (e.g., in lym ph om a). Alth ough no single periosteal reaction is un ique for a given tum or, a con tin uous periosteal reaction in dicates a lon g-stan din g (slow-growin g) ben ign process. An in terrupted reaction, on th e other hand, is com m only seen in m align an t tum ors. In th ese m align an t tum ors, th e periosteal response m ay appear in an onion skin (lam ellated) or sun burst pattern . Codm an ’s trian gle, a classic reactive periosteal cuff at th e periph ery of th e tum or, m ay also be seen. Som e unique radiographic fin din gs that poin t toward specific differential diagnoses are listed in Table 8.1.

Computed Tomography Th e m ajor value of a CT scan is to sh ow fin e detail in bon e. Th is in cludes bon e form ation as well as bon e destruction . In addition , CT scan s are th e best study to see wh eth er or

TABLE 8.1

DIFFERENTIAL DIAGNOSES ASSOCIATED WITH SPECIFIC RADIOGRAPHIC FINDINGS ■

■

■

■

■

■

■

■

■

■

Sclerotic soap bubble lesion in the anterior cortex of the shaft of the tibia: adamantinoma versus cortical fibrous dysplasia Sclerotic lesion with a central lytic nidus: osteoid osteoma versus stress fracture versus infection. Since many stress fractures or stress reactions involve intramedullary edema, they can mimic lymphomas. Sequential MRI (magnetic resonance imaging) scans will demonstrate healing of a stress reaction but no healing of a lymphoma that may appear stable or progressive. Cauliflower exophytic lesion: cauliflower osteochondroma versus secondary chondrosarcoma arising in an osteochondroma. Remember to measure the thickness of the cartilage cap. Multiple lesions in bone: metastases, myeloma, enchondromas, histiocytosis, fibrous dysplasia, nonossifying fibromas Lytic lesion in the humeral shaft in a child with no periosteal reaction: simple bone cyst Lytic lesions in the sacrum: chordoma, chondrosarcoma, giant cell tumor, metastasis, myeloma Calcified lesion on the surface of a bone: osteochondroma, periosteal osteosarcoma, parosteal osteosarcoma, myositis ossificans, periosteal chondroma, periosteal chondrosarcoma Aggressive meta-epiphyseal lesion in young patients (< 30 years): osteosarcoma, Ewing sarcoma, infection, aneurysmal bone cyst, giant cell tumor Aggressive meta-epiphyseal lesion in older patients (> 30 years): osteosarcoma, chondrosarcoma, metastasis, adult round cell tumors, giant cell tumor Lytic lesion in the epiphysis of a child with edema seen on MRI: chondroblastoma versus infection

n ot soft-tissue calcification is presen t. It is n ot optim al for looking for the extent of a perm eative lesion in bone or soft-tissue exten sion from a bon e lesion. CT m ay be particularly h elpful in difficult im agin g areas, such as th e pelvis, sacrum , an d vertebrae.

Magnetic Resonance Imaging For bon e-form in g tum ors, m agn etic reson an ce im agin g (MRI) scans are excellen t for showing the extent of a lesion in bone, the presen ce an d extent of edem a within or around bon e, an d the presence or absence of an associated soft-tissue com ponen t. MRI is the study of choice for any soft-tissue lesion. Th e addition of contrast to an MRI scan can also help elucidate areas of cyst form ation, wh ich do n ot con trast enh ance (but m ay sh ow rim en h an cem ent), from areas of solid tum or which frequently enh ance. One exception to th is are ch on droid lesion s, such as low-grade ch ondrosarcom a, which m ay also show rim enhancem ent with little in tern al en h an cem en t an d th us m im ic a cyst. O n e m ust always be careful in differen tiatin g between edem a in bon e an d tum or in bon e. For exam ple, lym ph om a frequen tly presen ts as h igh sign al in m arrow an d m ust be in the differential of traum atic m arrow lesions such as stress fracture. A lesion suspected to represent edem a in

Chapter 8: Overview of Musculoskeletal Neoplasms

bon e sh ould be followed by MR im agin g to resolution , an d a lack of resolution sh ould suggest the need for a biopsy.

Technetium Bone Scan Bone scans are m ost useful when utilized as a skeletal survey tool to look for the total num ber of lesions presen t or wh en a sin gular lesion is suspected but n ot seen on in itial x-ray. Most active lesion s th at eith er form bon e or gen erate a bone reaction are hot, whereas som e lytic lesion s that engender no bon e reaction m ay be n orm al or cold (e.g., myelom a). Positron Emission Tomography Positron em ission tom ography, or PET im agin g, represen ts an oth er tool in the diagnostic arm am entarium . Based on radion ucleotide tracin g of m etabolic activity, it can be used in th e diagnosis and sequen tial evaluation of bone and softtissue tum ors. The role of PET im agin g in m usculoskeletal on cology con tin ues to evolve.

Biopsy Not all lesion s require a biopsy, as m any ben ign an d in active lesion s m ay be diagn osed via im agin g studies alone. Th e ideal biopsy is on e th at provides all tissues n eeded to establish a h istologic diagn osis with out affectin g subsequen t treatm ent option s. Current biopsy options include both open an d n eedle tech n iques. In m ost location s, th e carefully perform ed open biopsy is still the gold stan dard, while needle biopsy techn iques are gaining in popularity. Th e advantage of a n eedle biopsy is that it m inim izes tissue con tam in ation in th e local tissues surroun din g a tum or. Needle tech n iques also m in im ize th e n eed for an esth esia an d can frequently be done outside an operating room , m inim izing expen se. Problem s associated with n eedle biopsies in clude sampling error and a frequent in ability to obtain sufficient tissue to m ake a definitive histologic diagnosis. Another question that arises, especially with open biopsy, con cern s wh o sh ould perform th e biopsy. Not all m usculoskeletal biopsies can be perform ed by orthopaedic on cologists, an d so h ow does on e decide wh eth er to perform a biopsy locally in the context of a general orthopaedic practice or to refer th e biopsy to a subspecialty trained surgeon? In general, if a surgeon sees a patient and knows from the in itial im aging studies that this is a lesion that h e or she would not treat prim arily, then the biopsy is best referred to th e treatin g surgeon . For exam ple, if a com m un ity orth opaedic surgeon sees an adolescent with an obvious osteosarcom a of th e fem ur that would not be appropriate to treat locally, then that biopsy is best referred to th e on cologist wh o will perform the defin itive treatm en t. The sam e m ay be true for a large deep m ass th ough t to m ost likely represen t a soft-tissue sarcom a. Regardless of wh o perform s the biopsy, Table 8.2 lists several fairly simple rules that m ust be adh ered to rigorously in order to avoid subsequen t problem s.

147

TABLE 8.2

GUIDELINES FOR BIOPSY 1. Make a small incision over the lesion in a manner that does not contaminate neurovascular structures. 2. The incision should be in line with a reasonable resection incision and typically should be longitudinal (not transverse) on the extremities. 3. In dealing with sufficiently large anatomic structures such as in the thigh or leg, it is better to go through one structure than between two, which would contaminate both. 4. Utilize minimal retraction so as to minimize adjacent tissue contamination with tumor. 5. Always make a small hole in a tumor capsule, especially if there is no tourniquet above the lesion, in order to minimize bleeding, which can be substantial. 6. Never use an Esmarch bandage over a tumor, as it could rupture the tumor into surrounding tissues. 7. Obtain a frozen section on the tissue obtained to make certain that you have diagnostic material. 8. If a drain is necessary, bring it out a short distance from either end of the incision inline with the incision so that the drain tract can be easily excised with a subsequent resection incision. 9. Perform a meticulous, watertight closure to prevent oozing and to promote primary healing of the biopsy to facilitate further treatment.

Staging Staging of a patient with a suspected m alignan t tum or is m andatory prior to definitive treatm ent. Fully characterizin g a lesion and its differential diagn osis prior to surgical biopsy preven ts m akin g wron g decision s th at m ay alter th e even tual outcom e an d m an agem en t. Stagin g studies for bon e an d soft-tissue sarcom as usually in cludes a CT scan of th e ch est an d an MRI of th e prim ary lesion . Oth er studies such as a CT scan of th e abdom en and pelvis or a techn etium bon e scan m ay also be in dicated, depen ding on th e specific diagn osis an d th e propen sity of th e tum or in question to m etastasize to areas oth er th an th e lun g. Th e Musculoskeletal Tum or Society adopted the Enneking Surgical Staging System for bone sarcom as (Table 8.3). Awh ole bon e, a join t, or a fun ction al m uscle group with a fascial boun dary is each con sidered a separate com partm en t in th is stagin g system .

TABLE 8.3

ENNEKING SURGICAL STAGING SYSTEM FOR BONE SARCOMAS (1986) Stage

Grade

Site

I

Low

II

High

III

Any grade with regional or distant metastasis

A: Intracompartmental B: Extracompartmental A: Intracompartmental B: Extracompartmental Any

148


TABLE 8.4

RADIOGRAPHIC DIFFERENTIAL DIAGNOSES OF BONE LESIONS Bone-Forming Tumors ■ ■ ■ ■ ■ ■

Osteoid osteoma Osteoblastoma Osteochondroma Osteosarcoma Blastic metastases Paget’s disease

Cartilage-Forming Tumors Osteochondroma ■ Chondromyxoid Fibroma ■ Chondroblastoma ■ Enchondroma ■ Chondrosarcoma ■

“Third List” ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■

■ ■ ■ ■

Differential Diagnosis It is on ly th rough in tellectual disciplin e an d diligen ce th at early diagn oses can be accom plish ed. Th e easiest way to assem ble a complete differen tial is to h ave m em orized or available a reason able list of com m on lesions to review as you con template each set of x-rays. With out such m en tal organ ization , it is difficult or impossible to assem ble a com prehensive differen tial diagn osis of a particular lesion . Table 8.4 con tain s a list of com m on n eoplasm s foun d in bon e separated in to bon e-form in g lesion s, cartilageform ing lesions, an d a “third list’’of m iscellaneous lesions. By going th rough these lists each tim e an x-ray is reviewed, on e can m ake sure to in clude m ost relevan t lesion s in a specific differential diagnosis. Prim ary bone tum ors can also be classified based on th eir direction of differen tiation (Table 8.5).

TABLE 8.5

CLASSIFICATION OF MUSCULOSKELETAL TUMORS BASED ON ORIGIN Bone tumors Bone origin: osteoid osteoma, osteoblastoma, osteosarcoma Cartilaginous origin: osteochondroma, chondroblastoma, chondromyxoid fibroma, enchondroma, periosteal chondroma, chondrosarcoma Fibrous origin: nonossifying fibroma, fibrous dysplasia, osteofibrous dysplasia, desmoplastic fibroma, fibrosarcoma Miscellaneous: unicameral bone cyst, aneurysmal bone cyst, giant cell tumor, Langerhans cell histiocytosis, Ewing sarcoma Musculoskeletal manifestations of leukemia Bone lymphomas Metastatic tumors: neuroblastoma, retinoblastoma, hepatoblastoma, lung, renal, prostate, breast, thyroid

Infection Metastasis Round cell tumors Ewing sarcoma Lymphoma Myeloma Neuroblastoma Fibrous dysplasia Nonossifying fibroma Simple bone cyst Aneurysmal bone cyst Eosinophilic granuloma (histiocytosis) Giant cell tumor Stress fracture Metabolic condition Hemangioma

Th e an atom ic location of a bon e tum or is also h elpful in n arrowing th e differen tial diagn osis, as m ost tum ors h ave a predilection for certain bone and even certain location s with in th ose bon es. With in a bon e, a tum or m ay be epiphyseal, m etaphyseal, or diaphyseal, an d cen tral or eccen tric. Table 8.6 classifies th e com m on bone lesions based on anatom ic location. In order to in clude or exclude lesion s in a differen tial diagn osis it is im perative th at th e orth opaedist h ave a clear

TABLE 8.6

COMMON LOCATIONS OF BONE TUMORS Epiphysis Pelvis Chondroblastoma, Ewing sarcoma Brodie’s abscess of the epiphysis, osteosarcoma Giant cell tumor, osteochondroma Fibrous dysplasia, metastasis Metaphysis, fibrous dysplasia Any tumor, anterior elements of spine Diaphysis, Langerhans cell histiocytosis Fibrous dysplasia, leukemia Osteofibrous dysplasia, adamantinoma metastatic Langerhans cell histiocytosis, giant cell tumor Ewing sarcoma, posterior elements of spine Leukemia, lymphoma, aneurysmal bone cyst Occasional diaphyseal, osteoblastoma Osteoid osteoma, osteoid osteoma Unicameral bone cyst, rib Multiple fibrous dysplasia Leukemia (metastasis), Langerhans cell histiocytosis Multiple hereditary exostoses, Ewing sarcoma Langerhans cell histiocytosis, metastasis Polyostotic fibrous dysplasia Enchondromatosis


im age of each archetype lesion as well as an appreciation of the variability possible within the range of presentations. It is also important to keep in m ind that not all bone form ing tum ors will show obvious bone form ation on an x-ray and the sam e is true of chondroid lesions, which also m ay sh ow no obvious chondroid calcification on plain x-ray. The following sections present the various types of bon e tum ors. Each section describes th e in ciden ce, clin ical presen tation , diagn ostic workup, an d brief treatm en t plan for each type of tum or. Th ese section s do n ot attem pt to presen t all possible lesion s; rather, there is a focus on m ore com m on lesions, on th e spectrum of disease, and on the un derlying diagn ostic th em es. Radiograph ic im ages are in cluded to dem on strate th e classic appearan ce of th ese lesion s. Th e ben ign tum ors of th e bon e for each of th e th ree categories outlin ed in Table 8.4 are presen ted first, followed by m alignant lesions.

BENIGN BONE LESIONS Bone Forming Osteoid Osteoma Osteoid osteom a (Fig. 8.1) is a com m on ben ign bon e tum or that affects m ostly ch ildren and young adults. Osteoid osteom as are associated with a classic pattern of con stan t pain , especially n igh t pain , wh ich is relieved very effectively but for sh ort periods with prostaglan din in h ibitin g drugs, such as aspirin and other nonsteroidal anti-in flam m atory drugs (NSAIDs). Th e fem ur, tibia, an d posterior spin e are the m ost com m on sites.

149

Th e lesion s appear as a sm all lytic n idus often with a “target’’ appearance surrounded by significant sclerosis. The “nidus’’m ay be sm all an d difficult to find on x-ray; it usually appears as a sm all focus (3 to 5 m m in diam eter) surroun ded by sign ifican t sclerosis. CT scan s with fin e cuts (i.e., 1 m m ) are th e study of ch oice for fin din g th e lesion . Bon e scintigraphy sh ows focal in ten se uptake. If NSAID use is n ot tolerated or sign ifican t pain persists, surgical treatm en t, in cludin g excision or radiofrequen cy ablation , m ay be used. If th e lesion is in a location wh ere RFA or surgical excision is excessively h azardous or m orbid, m edical treatm en t with lon g-term NSAIDs is reason able an d m ost lesion s becom e asymptom atic via spon tan eous regression within 4 years.

Osteoblastoma Osteoblastom a is m ost often seen in the posterior elem ents of th e spin e or in th e m eta-diaphyseal region of lon g bon es. Radiograph ically, osteoblastom a appears m ore lytic an d destructive th an osteoid osteom a. Th e n idus is usually 1 to 2 cm or occasion ally larger an d h as a less sclerotic surrounding bone. Histologically, osteoblastom a is nearly identical to osteoid osteom a, showing excessive osteoblastic activity and osteoid form ation with num erous gian t cells in a vascular fibrous strom a. Margin al resection or curettage an d bon e graftin g usually provide an acceptable lon g-term result, th ough recurrence is not uncom m on. Osteochondroma (Exostosis) Osteoch ondrom as (Fig. 8.2) are form ed by radial growth of bon e durin g ch ildh ood such th at th e lesion grows out

A

B Figure 8.1 Osteoid osteoma. Axial and coronal CT (computed tomography) images demonstrating the classic nidus with surrounding sclerosis of an ostoid osteoma.

150


A

B Figure 8.2 Peduncilated (A) and sessile (B) osteochondromas of the proximal humerus. (Reprinted

with permission from Greenspan A, Remagen W. Differential Diagnosis of Tumors and Tumor-like Lesions of Bones and Joints. Philadelphia, PA: Lippincott-Raven, 1998:148.)

away from th e bon e at an an gle from th e adjacen t growth plate. Th e cortex of th e bon e is con tin uous with th e cortex of th e lesion , an d th e m edullary can als are also con tin uous. Th is stan ds in con trast with parosteal osteosarcom a, for example, which grows on th e surface of an in tact cortex. Th ese lesion s can be sessile (broad based) or pedun culated (narrow based). Those that grow out of the flat bon es or th e proxim al fem urs can be very large an d take on a “cauliflower’’ appearan ce. Secon dary ch on drosarcom atous degen eration sh ould be suspected in any osteoch on drom a in an adult, wh ich grows or h as a large (greater than 2.5 cm ) and growing cartilage cap. Pain is also concerning in term s of poten tial m alignant transform ation but also occurs com m on ly in ben ign osteoch on drom as due to pressure on adjacen t structures. Multiple h ereditary exostoses is a rare, autosom al dom in an t disorder ch aracterized by m ultiple osteochondrom a th roughout the body; m alignant degeneration is m ore com m on in this in herited con dition th an in solitary lesion s (up to 28% vs. less th an 1%, respectively) Treatm ent in m ost cases is observation. Surgery m ay be in dicated for pain , deform ity, or m align an t degen eration .

Chondroid Forming Enchondroma Ench ondrom a (Fig. 8.3) is a nest of cartilage tissue typically in th e m etaphysis but occasionally diaphyseal that is usually en coun tered as an in ciden tal fin din g. En ch on dro-

Figure 8.3 An enchondroma is a nest of cartilage tissue typically

in the metaphysis of a long bone that is usually encountered as an incidental finding. (Reprinted with permission from Greenspan A, Remagen W. Differential Diagnosis of Tumors and Tumor-like Lesions of Bones and Joints. Philadelphia, PA: Lippincott-Raven, 1998:124.)

151


m as are m ost com m on in the short tubular bones of th e hands and in th e fem ur and hum erus. These lesion s ten d to be n on calcified or m in im ally calcified in youn g adults an d usually sh ow an in crease in calcification but n ot an in crease in size with follow-up over m any years. The calcification has a typical stippled or “popcorn’’pattern . Enchondrom a scan be difficult to distin guish from low-grade ch on drosacrom as, both radiograph ically and histologically. Th e h allm arks of ch on drosarcom a in clude m ore aggressive radiograph ic factors, such as in tralesion al lysis, en dosteal scallopin g, cortical th in n in g, erosion , or expan sion; clinically, pain distin guish es chondrosarcom as from ben ign en ch on drom a. Multiple en ch on drom as are rare but exist in Maffucci’s syn drom e (m ultiple en ch on drom as associated with system ic hem angiom as) or Ollier’s disease (m ultiple en ch on drom as, typically on on e side of th e body). Th ese patien ts h ave a h igh er rate of m align an t degen eration to ch on drosarcom a th an do th ose with solitary en ch on drom as.

Chondroblastoma Ch ondroblastom a (Fig. 8.4) typically presents as a painful lytic lesion in the epiphysis of a child, with significant edem a seen on MRI scan . In adolescen ts it can occasion ally grow across an old epiphyseal lin e to in volve th e adjacen t m etaphysis. The m ost com m on locations are the distal fem ur, proxim al tibia, and proxim al hum erus. The picture of a pain ful epiphyseal lytic lesion with abun dan t edem a m ay cause this lesion to be confused with infection or even

osteoch on dritis dessican s. Malign an t degen eration is extrem ely rare. Treatm en t con sists of in tralesion al curettage an d bon e graftin g.

“Third List” Aneurysmal Bone Cyst An eurysm al bon e cyst (ABC) (Fig. 8.5) is a n on n eoplastic reactive con dition th at is usually foun d in th e first th ree decades of life. ABCs occur in bon e as a prim ary de novo lesion, or th ey m ay occur in association with other vascular tum ors, such as giant cell tum or, Ewing sarcom a, osteosarcom a, or m etastatic ren al cell carcin om a. Prim ary lesions usually occur in the m etaphyses of long bones, especially in th e fem ur an d tibia, but th ey m ay also be seen in th e posterior spin e. Patien ts typically present with pain an d swellin g. Th e classic radiograph ic fin din g is an eccen tric, lytic, balloon in g expan sion with in th e m etaphysis. Lesions frequently have a delicate rim of expanded cortical bon e, wh ich m ay be best seen on CT scan ; fluid –fluid levels with in the lesion are usually seen on MRI scans. Typical histologic features are blood-filled spaces without en doth elial lin in g. Not all lesion s require treatm en t as th ey som etim es reach an in active state. Treatm ent is curettage and bone grafting, with a reasonably h igh rate of local recurren ce (25% or m ore). In ligh t of th e vascular n ature of th ese lesion s, em bolization h as also been reported as a h elpful adjuvan t or as prim ary treatm en t for lesion s of the spin e wh ere surgery m ay carry significant m orbidity.

A

B Figure 8.4 Chondroblastoma. A: Radiograph of lesion in proximal humeral epiphysis. B: CT (com-

puted tomography) shows the calcifications clearly. (Reprinted with permission from Greenspan A, Remagen W. Differential Diagnosis of Tumors and Tumor-like Lesions of Bones and Joints. Philadelphia, PA: Lippincott-Raven, 1998:161.)

152


A

B Figure 8.5 Anteroposterior (AP) and lateral radiographs demonstrating an aneurismal bone cyst

of the distal tibia. (Reprinted with permission from Greenspan A, Remagen W. Differential Diagnosis of Tumors and Tumor-like Lesions of Bones and Joints. Philadelphia, PA: Lippincott-Raven, 1998:331.)

Simple Bone Cyst Sim ple bon e cyst (Fig. 8.6), or un icam eral bon e cyst, is a com m on lesion that presen ts in the first two decades of life. Sim ple bon e cysts are a frequen t cause of path ologic fracture in ch ildren an d are frequen tly asymptom atic un til fracture. Th e lesion s occur alm ost exclusively in th e m etaph ases of lon g bon es, especially in th e proxim al h um erus, proxim al fem ur, an d proxim al tibia. Radiograph ically, th ey appear as a cen tral, full-width lytic area with sym m etric cortical thinn ing an d slight expan sion of the bon e. Unlike ABCs, they are rarely wider than the width of the adjacent physeal plate. The fallen leaf sign —signifyin g a piece of cortical bone that fell into the intram edullary cyst as a result of fracture—is often seen. Simple bone cysts usually h eal without in terven tion by th e tim e of skeletal m aturity, allowin g for observation in m ost cases. Larger lesions or those in weigh t-bearing location s can be treated with repeated aspiration and injection with m ethylprednisolon e, bone m arrow or bon e substitute, or with curettage an d bon e graftin g. Eosinophilic Granuloma Also known as solitary Langerhan’s cell histiocytosis (LCH), eosin oph ilic gran ulom a (Fig. 8.7 A+ B) is the m ost ben ign m em ber of a group of disorders of th e reticuloen doth elial system , in cludin g Han d –Sch uller–Ch ristian an d Letterer–Siwe syn drom es. LCH is a self-lim itin g process th at can lead to focal destruction of bone. It is m ost prevalent in the first and secon d decades, with half of patients younger than 10 years. Lesions are m ost com m on in the skull,

alth ough virtually any bone m ay be affected; vertebral involvem en t occurs in approxim ately 10% to 15% of cases. Th e m ost com m on appearan ce is a well-circum scribed m arrow lesion with n o periosteal reaction . Larger lesion s m ay dem on strate a m oth -eaten pattern with som e sclerosis. Occasionally, a periosteal reaction is produced in accordan ce with th e in flam m atory n ature of th e lesion . In th e spin e, LCH often presents as complete collapse of th e vertebral body with out spin e deform ity, wh ich is classically referred to as “vertebra plan a.’’ Wh ile LCH is th e m ost com m on cause of vertebra plan a, m align an t n eoplasm s and occasionally infections m ay m im ic this appearan ce. Treatm ent of symptom atic lesions in cludes curettage an d bon e graftin g. Local steroid in jection s h ave also been used. Chem otherapy is recom m ended in cases of dissem inated LCH.

Nonossifying Fibroma Non ossifyin g fibrom a (Fig. 8.8), or m etaphyseal fibrous defect, is a ben ign lesion left beh in d by th e growth plate in the course of endochon dral ossification. As such, it is n ever seen in the epiphysis. It is com m on ly seen in the lower extrem ity of children as an eccentric m etaphyseal lesion with a geographic m argin and surrounding sclerosis. As growth of th e patient continues and external rem odeling occurs, lesion s th at were previously in tram edullary in th e m etaphysis becom e intra-cortical in the m eta-diaphysis. Wh en th is occurs, cortical th in n in g is seen as th e rem odelin g bon e grows in to th e lesion . Wh ile m ost of th ese


A

153

B Figure 8.6 Simple bone cyst: “fallen fragment”. A: Pathologic fracture of proximal humeral diaphysis. B: Radiolucent lesion in the distal diaphysis of the fibula. (Reprinted with permission from Greenspan A, Remagen W. Differential Diagnosis of Tumors and Tumor-like Lesions of Bones and Joints. Philadelphia, PA: Lippincott-Raven, 1998:325.)

A

B

Figure 8.7 Anteroposterior (AP) x-ray (A) and coronal MRI (mag-

netic resonance imaging) (B) scan demonstrating an eosinophilic granuloma. (Reprinted with permission from Greenspan A, Remagen W. Differential Diagnosis of Tumors and Tumor-like Lesions of Bones and Joints. Philadelphia, PA: Lippincott-Raven, 1998: 251.)

Figure 8.8 A nonossifying fibroma of the distal tibia. (Reprinted


154


lesion s are asymptom atic, in ciden tal fin din gs requirin g on ly observation , larger lesion s m ay cause m ech an ical pain . In th is sm all percen tage of patien ts, curettage an d bon e graftin g m ay be n eeded to stop th e sym ptom s.

Giant Cell Tumor Gian t cell tum ors (Fig. 8.9) are ben ign but locally aggressive lesion s th at occur in th e juxta-articular region s of skeletally m ature in dividuals. Th e m ost com m on location s are about the knee; the distal fem ur and proxim al tibia accoun t for about 50% of all cases. Th e distal radius, pelvis, an d sacrum can also be involved. Pain is com m on, and pathologic frac-

A

ture can occur. Despite its benign classification, the tum or can m etastasize to th e lun gs in approxim ately 2% of cases. Located at the m etaphyseal–epiphyseal jun ction , th ese lesion s appear on radiograph s as lytic, juxta-articular lesion s with m oth -eaten m argin s an d cortical th in n in g but usually n o periosteal reaction . Histologically, th e lesion is com posed of m ultin ucleated gian t cells an d m on on uclear strom al cells, such that the nuclei in both cell populations are identical. Currently, m ost lesions are treated with aggressive intra-lesional surgery; this includes the creation of a large cortical win dow, followed by curettage an d burrin g. Adjuvan ts, such as phenol or liquid nitrogen , are popular, but

B

Figure 8.9 Giant cell tumor. A: Antero-

C

posterior and (B) lateral radiographs of a purely osteolytic lesion. C: An eccentric osteolytic lesion. (Reprinted with permission from Greenspan A, Remagen W. Differential Diagnosis of Tumors and Tumor-like Lesions of Bones and Joints. Philadelphia, PA: Lippincott-Raven, 1998:313.)


little data exist concernin g their contribution beyond that of a well-executed in tra-lesion al procedure. Packin g with bon e cem en t or bon e graft is th en perform ed to recon stitute the cavity. This approach has been shown to reduce recurren ce rates to 6% to 15%. Em bolization h as been em ployed for treatm en t of sacral gian t cell tum ors as a m in im al m orbidity prim ary line of therapy. Close follow-up for recurrent disease and pulm onary in volvem en t is importan t.

Fibrous Dysplasia Fibrous dysplasia (Fig. 8.10) is a disturban ce in bon eform ing processes that causes arrest in the woven state. It is m ost com m only diagnosed in the secon d or third decade. Virtually any bone m ay be involved, but the proxim al fem ur is the m ost com m on location. Other areas that are frequently involved in clude the tibia, pelvis, hum erus, radius, an d ribs. Mon ostotic disease is frequen tly an in ciden tal radiograph ic fin din g in an asymptom atic patien t. Polyostotic disease ten ds to rem ain un ilateral rather th an bilateral. Classic fibrous dysplasia occurs as a lon g lesion in a lon g bon e with ground glass appearance, m edullary calcification, and cortical thinnin g with out periosteal reaction. However, fibrous dysplasia has a broad spectrum of appearan ce, ran gin g from a very lon g lesion in a lon g bon e to a sm all eccen tric lytic lesion with surroun din g sclerosis. As such , fibrous dysplasia sh ould be in cluded in th e differen tial of every ben ign -appearin g lesion in bon e. Th e typical histologic appearance is m etaplastic woven bone scattered through a benign fibrous tissue strom a. O ften ,

155

the woven trabeculae are disorganized and have been described as havin g a “Chin ese letter’’ appearan ce. McCune – Albright syndrom e is a polyostotic disorder m anifested by brown ish skin lesion s an d en docrin e abn orm alities resultin g in precocious puberty. Fibrous dysplasia can very rarely convert to m alignan cy, m ost com m only osteosarcom a, although this occurs less than 0.5% of the tim e. Surgery is in dicated wh en th e patien t h as progressive deform ity, large lesion s with pain , n on un ion , failure of n on surgical th erapy, or m align an cy.

Hemangioma Hem an giom as (Fig. 8.11) of the spin e are com m on, occurrin g in approxim ately 10% of all adults an d are n otably m ore com m on in vertebral bodies than in the posterior elem ents. Hem angiom as typically contain trabecular conden sation s surroun ded by abnorm al vascular channels, which are m ore lucent on plain film s and CT and give the vertebral body vertical striation s on plain film s. Th is appearan ce is popularly referred to as a “jail house’’ vertebra; the appearan ce on axial CT im ages resem bles “polka-dots.’’Most spin al h em angiom as are inciden tal fin dings and require n o treatm en t. Sym ptom atic h em an giom as usually respon d well to con servative surgical procedures. Selective arterial em bolization is usually safer an d m ore effective treatm en t th an radiation . An terior resection an d fusion are reserved for pathologic collapse and neural comprom ise or refractory cases.

A

B Figure 8.10 Fibrous dysplasia of the diaphysis of the tibia (A) and femoral neck (B). (Reprinted


156


Figure 8.11 Anteroposterior (AP) (A) and lat-

A

MALIGNANT BONE LESIONS Bone Forming Osteosarcoma Th e classic form of osteosarcom a (Fig. 8.12) is seen m ost often in th e secon d an d th ird decades. Th e m ajority of lesion s are in the m etaphyses of the long bones, with 50% found about the knee. Males are at h igh er risk. Most patien ts h ave sym ptom s of pain before a m ass is n oticed. Radiograph ically, th ese are perm eative, m etaphyseal lesion s with soft-tissue exten sion and n ew bone form ation . Periosteal reaction is com m on an d frequen tly the new neoplastic bone takes on a sun burst or “h air on en d’’ appearan ce as th e tum or con tin ues to expan d in to th e soft tissue. Ch est CT scan s are essen tial for evaluation of pulm on ary m etastasis. Histologically, th ere is a presen ce of neoplastic woven bone in association with a m align an t spin dle cell strom a. Com m on subtypes of osteosarcom a are listed in Table 8.7. Ch em oth erapy is given preoperatively to reduce tum or burden an d to kill m align an t cells in the reactive zone and in m icrom etastases. This also causes the tum or to “h eal in ,’’ during wh ich tim e it shrin ks an d loses its vascularity, th us facilitatin g wide resection . Tum or n ecrosis due to ch em oth erapy is a progn ostic in dicator. Wide m argin surgical resection and reconstruction usin g segm en tal replacem en t en doprosth eses or allografts can then be perform ed. Adjuvant chem otherapy is given after resection . Curren tly, with th e use of ch em oth erapy an d surgery, survival rates are typically in th e ran ge of 65% to 75%. Secon dary osteosarcom a arises m ost frequen tly

B

eral (B) radiographs demonstrating the classic “jail house” vertebra of hemangioma. (Reprinted with permission from Greenspan A, Remagen W. Differential Diagnosis of Tumors and Tumor-like Lesions of Bones and Joints. Philadelphia, PA: LippincottRaven, 1998:291.)

from prior radiated fields or in the context of long-standing Paget’s disease.

Chondroid Forming Chondrosarcoma Malignant cartilage tum ors are prim arily tum ors of adulth ood and old age. About 85% of ch on drosarcom as (Fig. 8.13) are low-grade. Findin gs associated with ch ondrosarcom a in clude in tralesion al lysis, en dosteal scalloping, cortical thinn ing or expansion, and pain. Most will sh ow ch ondroid calcification, but high-grade lesions m ay take on a purely lytic appearan ce. Ch on drosarcom as are very resistant to radiation and chem oth erapy. Furtherm ore, they tend to recur locally and require complete surgical resection with a wide m argin to achieve cure. Th e treatm ent of low-grade is som ewh at controversial, as som e prefer aggressive in tralesion al curettage an d adjuvan t th erapy with phenol or liquid n itrogen wh ile others prefer wide excision . For in term ediate an d h igh -grade ch on drosarcom a, wide-m argins are required.

Other Lesions Ewing Sarcoma Ewin g sarcom a (Fig. 8.14) is an un differen tiated tum or ch aracterized by th e t(11;22) translocation in 90% of cases. It occurs prim arily in patien ts between 5 an d 25 years of age with a m ale predom in an ce. Twen ty percen t of patien ts will h ave associated system ic symptom s, such as fever, chills, an d a high erythrocyte sedim en tation rate and white blood


A

157

B Figure 8.12 Anteroposterior (AP) (A) and lateral (B) x-rays of the distal femur demonstrating

the aggressive nature of conventional osteosarcoma. (Reprinted with permission from Greenspan A, Remagen W. Differential Diagnosis of Tumors and Tumor-like Lesions of Bones and Joints. Philadelphia, PA: Lippincott-Raven, 1998:65.)

cell count; this clinical picture m ay m im ic osteomyelitis. Ewin g sarcom a classically presen ts as a diaphyseal, perm eative lesion with “onion skin’’periosteal reaction and a large associated soft-tissue m ass. The m ost com m on locations are the fem ur, pelvis, tibia, and hum erus. Histologically, Ewin g sarcom a con sists of sm all roun d cells arran ged in sh eets. The natural history is of an aggressive disease with approxim ately 20% of patients exh ibitin g m etastases on presen tation . Th ose with locally resectable disease fair well,

but th ose with advan ced m etastatic disease h ave at best a 30% survival rate at 5 years. Excision of lung m etastases, if possible, can im prove survival. Treatm en t is typically preoperative ch em oth erapy, wide surgical excision , an d adjuvan t ch em oth erapy. In cases wh ere resection results in positive m argin s, postoperative radiation is possible as th is tum or is radiosen sitive. Radiation m ay also replace surgical resection in areas where wide surgical excision is not feasible.

TABLE 8.7

SUBTYPES OF OSTEOSARCOMA ■

■

■

■

Parosteal osteosarcoma: A low-grade variant that occurs on the cortical surface of long bones, usually near the location of the metaphysis. It accounts for less than 5% of all osteosarcomas and occurs more often in females. The most common sites are the distal femur, proximal tibia, and proximal humerus. Treatment is wide surgical resection, which is often curative. Periosteal osteosarcoma: A surface-based osteosarcoma arising in long bones, typically in the diaphyses, and low to intermediate in grade. It accounts for less than 2% of all osteosarcoma. The most common sites are the distal femur, proximal tibia, and proximal humerus. It grows from under the periosteum, giving rise to the typical radiographic appearance of a sunburst-type lesion over a depressed cortical base. Treatment is wide surgical resection, with adjuvant chemotherapy for more advanced, higher grade lesions. Hemorrhagic osteosarcoma (telangiectatic): This is a high-grade variant that is extremely lytic and destructive. On radiographs, it resembles an aneurysmal bone cyst. Histologically, there is hemorrhage with malignant stromal cells and giant cells. Treatment is similar to classic osteosarcoma with similar outcomes. Secondary osteosarcoma: Secondary osteosarcoma may arise from many benign conditions including fibrous dysplasia, giant cell tumor, osteoblastoma, osteochondroma, Paget’s disease, and chronic osteomyelitis. Radiation-induced osteosarcoma can result after any significant radiation exposure, typically greater than 30 Gray. The average delay in onset is approximately 15 years but can vary widely. This subtype carries a poor prognosis with very high rates of metastasis.

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solitary myelom a in clude a solitary lesion on skeletal survey, histologic confirm ation, and bon e m arrow plasm acytosis. Treatm en t of ch oice in solitary plasm acytom a is radiation . Surgical in terven tion is typically reserved for decom pression of n eural structures in th e case of spin al in volvem en t and stabilization when the lon g bones are involved. MRI provides the earliest indication of local recurren ce, an d serum protein electroph oresis h as proven to be th e best in dicator of dissem in ation . Th e prim ary treatm en t for dissem in ated myelom a is system ic chem oth erapy.

Figure 8.13 Lateral radiograph of the distal femur demonstrat-

ing a calcified chondrosarcoma. (Reprinted with permission from Greenspan A, Remagen W. Differential Diagnosis of Tumors and Tumor-like Lesions of Bones and Joints. Philadelphia, PA: LippincottRaven, 1998:176.)

Primary Lymphoma of Bone Lym ph om a m ay presen t as an isolated tum or with in bon e or as a system ic disease. Prim ary lym ph om as of th e bon e (Fig. 8.15) accoun t for 3% of all m align an t bon e tum ors. Th ese patien ts typically h ave n on e of th e gen eral con stitution al com plain ts so com m on ly associated with system ic lymph om a, even wh en lesion s are exten sive. Lymphom a is typically a very perm eative but m inim ally destructive lesion . Th e usual progression is th at lym ph om as fill up th e m edullary can al an d th en grow in to th e surroun din g soft tissues while causing little destruction of the bone itself. Plain radiographs m ay be un rem arkable, while MRI scans sh ow m arrow replacem en t and often an associated soft-tissue m ass. Surgical in terven tion is typically reserved for select cases to prevent or treat pathologic fracture; prim ary treatm en t cen ters on radiation an d m ultiagen t ch em oth erapy. Plasmacytoma and Multiple Myeloma (Plasma Cell Tumor) Solitary myelom a is on e of m any B-cell lym ph oproliferative diseases, wh ich also in clude m ultiple myelom a. True solitary myelom a is relatively rare, accounting for on ly 3% of all plasm a cell n eoplasm s. Mon oclon al protein s are m ore often absen t or un detectable in solitary myelom a compared with m ultiple myelom a. Diagnostic criteria for

Chordoma Ch ordom a (Fig. 8.16) is a low-grade, relatively uncom m on m alignancy of the spine typically foun d in patien ts in th eir fourth to sixth decade. Chordom as routinely localize to th e m idline, arise from prim itive n otochord rem nants, and are prim arily foun d in th e sacro-coccygeal area or at th e base of th e skull. Ch ordom as grow slowly with few early symptom s, frequen tly reach in g con siderable size before diagn osis. Many patients, h owever, have a long history of m ild aching perineal pain or num bn ess, which should be a sign of a poten tial pelvic tum or compressin g th e sacral plexus. Often chordom as can be palpated directly on rectal exam ination. Surgical resection with wide m argin s is the only curative procedure. Sin ce the tum or is a low-grade lesion, growth is slow an d recurren ce an d even tual m etastases are com m on.

SOFT-TISSUE TUMORS Clinical Presentations Most soft-tissue tum ors present with pain and/ or a m ass. It is also rem arkable that soft-tissue m asses includin g sarcom as can reach trem endous size and yet cause m inim al or n o symptom s. Many patien ts falsely assum e th at because the lesion is painless it m ust also be harm less. This is obviously n ot th e case but is often respon sible for lon g delays in diagnosis on the part of the patient or, less frequently, the physician . Ironically, the lesions in soft tissue that are m ost com m only painful are the benign soft-tissue tum ors, including desm oid tum ors, hem an giom as, benign nerve sh eath tum ors, an d soft-tissue infections.

Radiographic Evaluation Most soft-tissue m asses are seen poorly or not at all on plain x-rays; h owever, th ose th at sh ow calcification will be m ore apparent. Th e m ost com m on lesion to present with soft-tissue calcification is myositis ossificans, but synovial sarcom a can presen t in a sim ilar m anner. Myositis typically exh ibits h istologic periph eral m aturation an d an associated “egg shell’’ calcification, while m align ant soft-tissue


A,B

159

C,D

Figure 8.14 Ewing sarcoma. A: Anteropos-

E

tum ors are usually less organized, so any calcification is m ore ran dom . Th e classic MRI fin din g in m ost soft-tissue tum ors is a lesion th at is well circum scribed an d low sign al (dark) on T1, an d h igh sign al (brigh t) on T2, fat-suppressed T2, or sh ort tau in version recovery (STIR) sequen ces. Such a lesion would support benign tum or, m alignan t tum or, abscess, cyst, or hem atom a in the differential diagnosis. Most soft-tissue sarcom as are very distinct, wh ile often showing a bit of edem a in the compartm ent in wh ich they occur. O n th e con trary, m any ben ign lesion s are poorly m arginated on MRI scan s; these include desm oid tum ors, hem angiom as, in flam m ation , in jury, and infection. This is

terior and (B) lateral radiographs. C: Coronal and (D) sagittal T1-weighted MRI (magnetic resonance imaging). E: Axial T2-weighted MRI. (Reprinted with permission from Greenspan A, Remagen W. Differential Diagnosis of Tumors and Tumor-like Lesions of Bones and Joints. Philadelphia, PA: Lippincott-Raven, 1998:260.)

the opposite of wh at is seen in bone, wh ere ben ign lesions ten d to be well m argin ated, an d m align an t tum ors ten d to be poorly m argin ated.

Differential Diagnosis As in th e case of bon e lesion s, soft-tissue tum ors can be quite con fusin g wh en approach ed as a large n um ber of un related topics. Again , a system atic approach to th e diagn osis of th ese lesion s reveals a lim ited n um ber of clin ical presen tation s. Histologically, h owever, th ey do form a large and diverse group with fewer trends than those found in bon e tum ors.

160


A,B

C Figure 8.15 Multiple radiographs demonstrating the variable appearance of primary lymphoma of the bone. (Reprinted with permission from Greenspan A, Remagen W. Differential Diagnosis of Tumors and Tumor-like Lesions of Bones and Joints. Philadelphia, PA: Lippincott-Raven, 1998:268.)

FATTY TUMORS Lipoma Th is is on e of th e few diagn oses th at can be m ade con fiden tly on th e basis of MRI an d clin ical fin din gs alon e. Benign lipom as appear as m asses of uniform fat den sity and parallel th e appearan ce of n orm al subcutan eous fat on all sequen ces: bright on T1 and T2 sequen ces and dark on fatsuppressed T2 and STIR sequences. Therefore, a m ass seen on MRI as a un iform fat den sity with n o in terstitial m arkin gs is diagn ostic of ben ign lipom a. Histologically, lipom as consist of m ature fat cells with n o atypia. With out symptom s, th ese lesion s can be m on itored. If excision is warranted, m argin al resection h as a low recurrence rate. Several lipom a varian ts exist, in cludin g fibrolipom a, an giolipom a, spin dle cell lipom a, and hibernom a. These lesion s have a differen t appearan ce from sim ple lipom a an d frequen tly require biopsy to establish a defin itive diagn osis.

Atypical Lipoma Con tin uin g alon g th e spectrum of fatty tum ors, th is ben ign tum or h as also been labeled “well differen tiated liposarcom a’’ and “lipom a-like well differentiated liposarcom a,’’ especially wh en foun d in th e retroperiton eum . Th is is a fatcontainin g lesion ch aracterized by lobules of fat signal on

MRI with surroundin g layers of fibrous tissue dem onstrating thin layers of h igh signal that enh ance with the use of intravenous contrast. Histologically, lobules of norm al fat are seen surroun ded by fibrous bands con tain ing lipoblasts and atypical cells. These lesions are very invasive into surroun din g tissue, an d local recurren ce followin g excision is com m on . Wh ile atypical lipom as do n ot m etastasize, th ey do carry a 10% risk of m align an t tran sform ation , usually to high-grade liposarcom a. Myxoid liposarcom a and pleom orphic liposarcom a exist at the far end of th e fatty tum or spectrum , represen ting two variants with aggressive, m align an t features.

FIBROUS Desmoid Tumor (Fibromatosis) Desm oid tum ors are an un com m on group of ben ign softtissue neoplasm s with aggressive local behavior. They appear on MRI scan s as den se fibrosis, typically rem ain in g dark on T1, T2, an d fat-suppressed T2 sequen ces. Un like m ost soft-tissue tum ors, they are poorly m arginated and often h ave a stellate m argin on MRI, reflectin g th eir extrem e invasiveness in to surrounding tissues. They are frequen tly pain ful an d dem on strate an in creased in ciden ce in wom en following pregnancy. Histologically, desm oid tum ors are composed of benign-appearin g spindle cells


A

161

B

Figure 8.16 Anteroposterior (AP) radiograph (A), axial CT (com-

C

puted tomography) scan (B) and axial T-1 weighted MRI (magnetic resonance imaging) scan (C) demonstrating a chordoma. This tumor of notochord remnants occurs almost exclusively in the sacrum or at the base of the skull. (Reprinted with permission from Greenspan A, Remagen W. Differential Diagnosis of Tumors and Tumor-like Lesions of Bones and Joints. Philadelphia, PA: Lippincott-Raven, 1998:355.)

interspersed am id a background of abun dant collagen fibers. Wh ile desm oid tum ors are ben ign , th ey are very aggressive locally and h ave a trem endous ability to in vade local tissues at a considerable distance from the prim ary tum or. Surgery has historically been the m ainstay of treatm en t but has a very high failure rate an d considerable associated m orbidity. Therefore, nonsurgical treatm ents such as low-dose chem otherapy and radiation therapy have also been popular, eith er as sole treatm en t or as part of a m ultidisciplin ary treatm en t regim en .

fibrosarcom as presen t a un ique picture of m align an t spin dle cells arran ged in a h errin gbon e pattern with m arked cellularity and m oderate atypia. Local control is usually ach ieved with a com bin ation of wide m argin al excision an d adjuvan t or n eo-adjuvan t radiation th erapy. As ch em oth erapy h as progressed, so h as en th usiasm for its use as an adjuvan t in patien ts with large (> 5 cm ), high-grade soft-tissue sarcom as that dem onstrate reasonable m edical risk for th is therapy.

Fibrosarcoma

MYXOID

Fibrosarcom a is a rare soft-tissue sarcom a. Clin ically, it appears as a typical soft-tissue m alignan cy usually presen ting as a painless m ass. MRI fin dings are typical for the group of soft-tissue sarcom as dem onstrating dark signal on T1 an d bright sign al on fat-suppressed T2 sequen ces, alon g with con trast en h an cem en t. Histologically,

Myxoma Ben ign myxom as are typically seen with in skeletal m uscle, wh ere th ey usually presen t as a pain less m ass. Th ey do dem on strate a fairly typical appearan ce on MRI scan n in g: th ey are usually darker th an m uscle on T1 an d un iform ly

162


brigh t on fat-suppressed T2 views, with som e edem a usually alon g th e in ferior an d superior aspects. Th is is, h owever, n ot diagn ostic for ben ign myxom a an d can be seen with other soft-tissue m asses, both benign and m alignant. Treatm ent is m arginal excision and recurren ce is rare.

Low-Grade and High-Grade Fibromyxosarcoma Th ese lesion s exten d th e spectrum of myxoid soft-tissue tum ors an d represen t grades of atypia an d cellularity. Th ese lesion s are n oted for th eir h eterogen eity, an d samplin g error in biopsy can be a problem . Histologically, th ey are comprised of loose myxoid tissue sh owin g atypical cells in a loose m atrix. High er grade lesion s sh ow m ore cellularity, atypia, an d n ecrosis.

NEURAL Benign Schwannoma Th is is a ben ign tum or foun d in periph eral n erves, m ost com m only in spinal roots and in the m ajor n erves of the extrem ities. On MRI im agin g, sch wan n om as dem on strate a typical soft-tissue tum or pattern sh owin g low sign al on T1 an d h igh sign al on fat-suppressed T2 sequen ces. Sin ce th ey occur com m on ly with in periph eral n erves, th ey typically have a fusiform shape an d are lon g in th e longitudinal axis of th e extrem ity. Histologically, th e lesion is described as having dense Antoni A (compact spin dle cells, often in a whorl-like pattern) an d loose An ton i B (less cellular an d orderly) areas. Verucae bodies exh ibit typical pattern in g of spin dle cells. Malignan t tran sform ation is extrem ely rare. Most of th ese lesion s are symptom atic an d dem on strate a positive Tin el’s sign (sh ootin g pain with percussion of the lesion). In light of this, m ost lesions require surgical excision . Sin ce th ese lesion s frequen tly occur with in th e neural sh eath of m ajor n erves, excision of the lesion sh ould be carried out in such a m an n er as to protect th e n erve of origin as m uch as possible.

Neurofibroma Solitary n eurofibrom a is a ben ign , fibrotic, fusiform tum or arisin g from a periph eral n erve; th e n erve of origin m ay be too sm all to recogn ize. It occurs m ost com m on ly in th e th ird to sixth decades. Th e lesion is usually asymptom atic except for th e presen ce of a m ass. Treatm en t is excision . In neurofibrom atosis, or Von Recklinghausen ’s disease, sm all café au lait spots appear in the first few years of life, alon g with m ultiple n eurofibrom as, wh ich develop later. Th e n eurofibrom as appear as soft pedun culated n odules in th e skin or as firm or soft m asses in th e deeper

tissues. Malignant degeneration of these neurofibrom as in Von Recklin gh ausen ’s disease is m uch m ore com m on (3% to 5% of patients) th an in the solitary variant. When indicated, defin itive treatm en t for ben ign n eurofibrom as is excision .

BENIGN SYNOVIAL PROLIFERATIVE DISORDERS Synovial Chondromatosis Th is is a ben ign , un com m on disorder ch aracterized by m etaplastic proliferation of cartilaginous n odules in the syn ovial m em bran e of joints. Typically diagn osed in the third to fifth decade, it is m ost often found in the knee, followed by the hip, shoulder, and elbow. Pain and swellin g are the m ost com m on complain ts, but joint effusion, tendern ess, an d lim ited ran ge of m otion occur. Th e radiograph ic fin din gs ran ge from sim ple join t effusion to m ultiple radiopaque join t bodies, depen ding on the degree of calcification of th e cartilagin ous n odules. MRI m ay sh ow the calcifications as signal void on T2-weigh ted im ages, with a high-signal intensity background of in flam ed, hyperplastic syn ovium . Clin ically, syn ovial ch on drom atosis m ay appear as distinct osteochondral bodies in the syn ovium or as m asses of confluent cartilage. Synovectomy, eith er open or arth roscopic, with rem oval of th e lesion is the treatm ent of choice, although recurrence is com m on.

Pigmented Villonodular Synovitis Pigm en ted villon odular syn ovitis ( PVNS) is a locally destructive fibroh istiocytic proliferation, which affects join ts, bursae, an d ten don sh eath s. Clin ically, PVNS is a slowly progressin g process th at causes pain an d join t swellin g, often with lim ited ran ge of m otion . Th e kn ee is th e m ost com m on location. More than half of patients present with a bloody join t effusion . Th us, a patien t with bloody effusion of th e kn ee with out traum a is suggestive of this diagn osis. On radiograph s a soft-tissue den sity is often presen t in th e affected joint. This is som etim es interpreted as a joint effusion , but it is den ser because of th e h em orrh agic fluid an d lobulated synovial tissue. Calcifications are rare. PVNS appears dark on T1, T2 and fat-suppressed T2 sequences due to th e presen ce of h em osiderin pigm en t; gradien t ech o sequences are often h elpful in ch aracterizing th e lesion. PVNSfrequen tly occurs also outside of a join t in association with ten osyn ovial tissue. In th ese cases, th e lesion is term ed “giant cell tum or of tendon sheath,” but it is histologically identical to PVNS. Treatm en t for PVNS consists of synovectomy. Wh ile arth roscopic procedures h ave less m orbidity than open procedures, th ey probably carry a higher risk of recurren ce.


163

(Fig. 8.17) in clude a soft-tissue m ass often close to a join t. Soft-tissue calcification s are presen t in about 15% of cases an d m ay presen t with a sligh t am oun t of calcification or sh ow diffuse calcification to th e extent th at the lesion m im ics m ature myositis ossifican s. Syn ovial sarcom a can also develop sign ifican t cystic areas m im ickin g a syn ovial cyst or diffuse h em orrh age m im ickin g a h em atom a. Histologically th e classic pattern is a biph asic picture of m align an t spin dle cells in association with areas of colum n ar epithelium . In th ese cases, th e m align an t strom al cells are positive for vim entin (a m esenchym al m arker) but also show cytokeratin positivity in th e epith elial cells. Treatm en t is th e sam e as for m ost soft-tissue sarcom as an d h as been described in the section on fibrosarcom a.

Malignant Fibrous Histiocytoma

Figure 8.17 Lateral radiograph of the ankle demonstrating a

calcified soft-tissue mass which is characteristic of synovial cell sarcoma. (Reprinted with permission from Greenspan A, Remagen W. Differential Diagnosis of Tumors and Tumor-like Lesions of Bones and Joints. Philadelphia, PA: Lippincott-Raven, 1998:410.)

OTHER Synovial Sarcoma Despite its n am e, th is lesion does n ot arise from syn ovium . It comprises 8% to 10% of soft-tissue sarcom as an d typically occurs before the age of 50. The m ost com m on sites are around th e kn ee and foot. Most of these tum ors occur in an extra-articular location, but very rarely m ay be intra-articular. The radiologic features of synovial sarcom a

Malignant fibrous histiocytom a (MFH) is the m ost com m on soft-tissue sarcom a of adulthood. Sim ilar to other soft-tissue m alignan cies, it usually presen ts as a painless deep soft-tissue m ass. Histologically, it is com posed of atypical spin dle cells in a whorled or cartwheel con figuration. In accordan ce with its h igh -grade status, it is a very cellular tum or with significant atypia an d necrosis. MFH is basically a diagn osis of exclusion as it is a tum or th at fits n o oth er m ore specific tum or type.

BASIC TREATMENT PRINCIPLES In treatin g m usculoskeletal tum ors, th ere are basically th ree m odes of treatm ent available: surgery, radiation therapy, and chem oth erapy. In rare cases, m odalities such as radiofrequen cy ablation or em bolization m ay also be available. In order to understand how surgery fits in to this scen ario, it is critical to understand the oncologic surgical m argins that can be obtained. Th e term s used for th ese m argin s in con tem porary treatm en t were popularized by Enn eking and are defin ed as intra-lesional, m arginal,

TABLE 8.8

TREATMENT MATRIX FOR BONE AND SOFT-TISSUE SARCOMAS Sarcoma Treatment Modalities Radio Resistant

Radio Sensitive

Low grade

Surgery ■ Chondrosarcoma ■ Chordoma ■ Adamantinoma

Surgery + radiation ■ Low-grade soft-tissue sarcomas

High grade

Surgery + chemotherapy ■ Osteosarcoma ■ Ewing sarcoma ■ Other high-grade bone sarcomas

Surgery + radiation + chemotherapy ■ High-grade soft-tissue sarcomas

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wide, and radical. For th e m ost part, benign tum ors of bon e, such as gian t cell tum or, osteoblastom a, ch on droblastom a, an d ch on dromyxoid fibrom a, are treated with in tra-lesion al surgery. Ben ign lesion s in soft tissue, such as lipom a, sch wan n om a, an d myxom a, are treated with simple m argin al excision . Table 8.8 dem onstrates a general treatm en t m atrix for bon e an d soft-tissue m align an cies.

RECOMMENDED READING Lewis VO. What’s new in m usculoskeletal oncology. J Bone Joint Surg Am. 2007;89(6):1399 –1407. Sim FH, Frassica FJ, Frassica DA. Soft-tissue tum ors: diagn osis, evaluation , an d m an agem en t. J Am Acad Orthop Surg. 1994;2(4):202 –211. Weber K, Dam ron TA, Frassica FJ, Sim FH. Malignan t bon e tum ors. Instr Course Lect. 2008;57:673 –688.

Principles of Sports Medicine F. W in ston Gwathm ey Jr.

Joseph M. Hart

INTRODUCTION Medicine and sports share a com m on origin in ancient Greece. Hippocrates, un iversally regarded as th e fath er of m edicine, was also am ong history’s first sports physicians. Th e leadin g ath letes of h is tim e participated in th e O lympic Gam es, an d h e was proficien t at treatin g th eir in juries, dressin g th eir woun ds, splin tin g fractures, an d stitch in g laceration s. Th e Hippocratic m eth od for reducin g a sh oulder dislocation rem ain s in use in to m odern tim es. Wh en Galen was appointed physician for the gladiators of Pergam um , he arguably becam e history’s first team physician . His athletes frequently sustain ed traum atic wounds inflicted by heavy weapon s and wild an im als, and in the m anagem ent of th ese in juries, h e gain ed in valuable in sigh t in to th e fun ction of m uscles, n erves, and blood vessels. In m odern tim es, th e proliferation of organ ized sports in society h as stim ulated th e evolution of sports m edicine an d has established th e physician as an integral m em ber of th e ath letic com m un ity. Physician in volvem en t in th e m odern Olympic Gam es reflects this developing role. Prior to 1924, th e U.S. Olympics team traveled with out a physician or other h ealth care provider. In 2008, a team of 61 health care profession als representin g m ultiple specialties including orth opaedics, cardiology, obstetrics and gynecology, in tern al m edicin e, em ergen cy m edicin e, an d pediatrics traveled to Beijing with the O lympics ath letes. Sports m edicin e is a field dedicated to th e preven tion an d treatm ent of athletic injuries and diseases and en com passes m ultiple disciplin es collectively in volved in th e care of ath letes. Th e ath lete represen ts a un ique patien t as success in sports directly correlates with strength, condition ing, an d physical and m ental well-being. To provide optim al care, a compreh en sive approach involving physician s,

9

Mark D. Miller

ath letic train ers, th erapists, an d n utrition ists is required. Th e inh eren t diversity of th e ath letic population presents ch allen ges to th e h ealth care provider as patien ts m ay ran ge from the youth soccer player to the elderly golfer and from the recreational run ner to the high-level collegiate or professional athlete. The conditions and injuries th at affect this population vary substan tially with age, gen der, sport, an d level of perform an ce. Con sequen tly, th e m eth od of diagn osis an d treatm en t m ust be tailored to each patien t and each situation . Th e degree of physician in volvem en t in th e care of ath letes also depen ds upon th e physician , th e sport, an d th e level of perform an ce. For th e m ajority of ath letes, th e gen eral practition er plays th e role of sports physician . For h igh-level athletic organization s an d in stitution s, the daily h ealth an d train ing dem an ds require dedicated physicians respon sible for coordin atin g th e care of th e players on th e team . Th ese physician s provide care for ath letes across th e en tire spectrum of th eir participation an d m ay be th eir on ly doctor in m any cases. Th is ch apter address m any of th e issues specific to th e care of athletes, including the role of th e team physician, eth ical issues in sports m edicin e, preparticipation evaluation , ath letic even t coverage, com m on ath letic in juries, m edical con dition s effectin g ath letes, th e care of th e fem ale ath lete, prin ciples of ath letic reh abilitation , th e ph arm acology of sports m edicin e, an d ath letic n utrition .

THE TEAM PHYSICIAN Th e role of team physician requires a broad un derstan ding of m edicin e as it applies to th e ath lete and th e ability to quarterback a team of h ealth care providers, which

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in clude ath letic train ers, physical th erapists, n utrition ists, dietician s, an d oth er h ealth care specialists. It is im portan t for th e team physician to involve the coaches and parents to facilitate com m un ication an d to en sure th at appropriate train in g regim en s an d precaution s are implem en ted to preven t in juries. Dr. Fran k McCue, th e lon g-tim e team physician at th e University of Virginia, outlin es th e three A’s of being a team physician : availability, affability, an d ability. Availabilityis im perative to providin g optim al care for th e ath lete, an d th e team physician m ust be accessible th rough out th e season an d off-season . In juries occur with out warn in g an d th e physician m ust be at h an d to direct care, especially for em ergen cies. Respon sibilities in clude gam e coverage, evaluation on th e sidelin es an d in th e train in g room , an d ath lete clinics. The team physician m ust possess affabilityto forge stron g relation sh ips with th e players, coach es, paren ts, train ers, an d oth er h ealth care providers. Developin g trust with in these relationships strengthens the physician –patien t in teraction an d optim izes care. At the foundation of serving as team physician is th e ability to diagn ose an d treat ath letic in juries. Th e physician m ust un derstan d th e rules an d physical requirem en ts particular to th e sport to address th e con dition s th at m ay arise from participation. Often the team physician is the prim ary care provider for the athlete, and thus a broad understan din g of th e m edical con dition s th at afflict th is patien t population is crucial to en sure proper treatm en t.

ETHICS IN SPORTS MEDICINE Sin ce th e earliest in teraction between sports an d m edicin e, the disparate objectives of the athlete who desired victory an d th e physician wh o sough t good h ealth h ave stim ulated conflict. Hippocrates and Galen criticized the im m oderate ath letic lifestyle an d felt th at th e stren uous train in g, excessive diets, an d obsession with winnin g con stituted unhealthy and dangerous beh avior. The tim elessness of th ese concerns is reflected in m any of the challenges that face the m odern sports physician . It would seem that sports prom ote h ealthy lifestyle, but th e dem an ds of train in g, th e in satiable desire to win , an d th e urge to play th rough in jury are often detrim en tal to h ealth , both in th e sh ort an d lon g term . The sports physician m ust recognize the im m ense pressure athletes face to play and perform . Athletes strive to ach ieve in th eir sports, som etim es at th e risk of en dan gerin g th eir h ealth . Excessive train in g an d dietin g as well as th e temptation s of perform an ce-en h an cin g substan ces are com m onplace am on g ath letes at every level. In addition , a th ird party is in troduced in to th e doctor–patien t relation sh ip in th e form of th e team or organ ization . A team relies upon its ath letes to succeed, an d th e goals of th e

team m ay in terfere with th e best in terests of th e players. Collegiate and professional team s endure the expectations of th e adm in istration , m edia, an d fan s. Clear com m un ication between the health care team and the coaching staff is important to alleviate un due stress on the athlete and to establish a realistic un derstan din g of an ath lete’s capability to participate. Th e team physician sh ould also be aware of th e social and finan cial influen ces of athletics. The ability to perform on th e ath letic field m ay provide ath letes with an opportun ity to attend college on a sch olarsh ip or en gage in a lucrative career as a professional athlete. Th ese m otivations m ay com pel players to abuse perform an ce-en h an cin g drugs or en gage in oth er illegal or un h ealthy beh avior.

PREPARTICIPATION EVALUATION Th e preparticipation evaluation is th e key to th e preven tion of sports-related disease and injury. The objective of this assessm ent is to screen potentially disabling or lifethreaten ing disorders and identify condition s that predispose to in jury or illn ess. It also serves to determ in e th e gen eral h ealth of th e ath lete an d provides an en try poin t in to the health care system for adolescents. All athletes participatin g in organ ized h igh sch ool, college, an d profession al sports are required to un dergo this system atic assessm ent before bein g cleared to play. Ideally, th e preparticipation evaluation sh ould take place 6 weeks before th e start of th e sports season so that issues that arise m ay be addressed prior to participation. For practical purposes, a complete evaluation need be perform ed on ly upon en try to a h igh er level of participation , while an interim h ealth questionn aire and lim ited, focused exam ination suffices in subsequent years. The objectives an d focus of th e evaluation sh ift as ath letes get older. Am on g youn ger ath letes, screen in g preexistin g m edical and congenital con ditions that affect participation takes preceden ce. Th e likelih ood of discoverin g a serious preexisting condition dim in ishes as ath letes advance and un dergo yearly assessm en ts. At h igh er levels, th e physician m ay concentrate on age- or sport-specific issues, and previous in juries and concerns related to trainin g and play sh ould be addressed. Th e preparticipation evaluation m ay take place eith er in th e physician’s office on an individualized basis or in a m ass screening settin g such as a high school gym n asium . Wh ile th e office h as th e advan tage of fostering the doctor–patien t relation sh ip, m ost physician s h ave lim ited tim e available, especially during the tim e of year that m ost evaluations need to be completed. The m ass screenin g ven ue allows for evaluation of a larger num ber of athletes quickly an d in troduces th e ability to utilize a collaboration of h ealth care providers with con dition -specific train in g. In addition, direct access to th e coaching an d athletic training

Chapter 9: Principles of Sports Medicine

staff is afforded by perform in g evaluations at the athlete’s sch ool.

Health Questionnaire A h ealth question n aire sh ould be completed carefully in advance by th e athlete with input from parents an d th e prim ary care provider. The questionn aire identifies the m ajority of poten tial problem s an d sh ould focus on developm en tal and m edical, fam ily, social, allergies, m edications, an d im m unization history. Th e review of m edical h istory sh ould address recent illnesses, neurological deficits and prior h ead in juries, h eart an d lun g con dition s, m usculoskeletal problem s, loss of organs, previous h eat illness, substan ce or supplem en t abuse, and, in the fem ale ath lete, disordered eatin g an d m en strual abn orm alities. Th e cardiovascular portion of th e h istory is especially im portan t as heart disease is implicated in 95% of sudden deaths in athletes youn ger than 30 years. A prior occurrence of exertion al ch est pain or syn cope, exercise-associated fatigue, heart m urm urs, arrhythm ia, history of elevated blood pressure, or a fam ily history of prem ature death or disability secon dary to cardiovascular disease sh ould raise red flags an d need to be explored. The m edical h istory questionnaire sh ould be carefully reviewed by a health care profession al an d appropriate workup for any concernin g elem ents of the history m ust be un dertaken prior to participation.

Physical Examination Once the m edical history has been obtained, the athlete sh ould undergo a th orough but focused physical exam in ation. Recording and tracking the h eigh t, weight, and body m ass index of each athlete m ay identify disordered eating, steroid use, or obesity. Vital signs should be taken , an d irregularities in pulse rate, blood pressure, or respiratory rate warrant further workup. HEENT: Th e physical exam in ation gen erally starts with the head, eyes, ears, n ose, and th roat. Poor vision, strabism us, astigm atism , refractive errors, and anisocoria sh ould prompt referral. Eye protection is required for ath letes with corrected vision less than 20/ 40, absence of one eye, or history of eye traum a or surgery. Cardiovascular: According to the Am erican Heart Association , th e cardiovascular exam ination should in clude blood pressure m easurem en t, auscultation for m urm urs, palpation of lower extrem ity pulses, an d assessin g for stigm ata of Marfan syndrom e. Electrocardiography is indicated for any abnorm al heart rhythm and m ay iden tify potentially lethal arrhythm ias. Murm urs sh ould be assessed in stan ding and supine positions, an d cardiology referral is recom m en ded for sign ifican t systolic m urm ur (> 3/ 6), any diastolic m urm urs, an d all m urm urs am plified by stan din g or Valsalva m an euver.

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Lungs: Th e lun g exam in ation sh ould focus on detection of abn orm al breath soun ds, use of accessory respiratory m uscles, an d presence of cough . Asth m a is am ong the m ost com m on conditions facing youn g athletes and is ch aracterized by ch est tigh tn ess, wh eezin g, an d sh ortn ess of breath . Exercise-in duced bron ch ospasm is n ot reliably detected durin g preparticipation screen in g, an d any ath lete wh o reports asth m a-like symptom s after exertion should un dergo form al testin g. Gastrointestinal/Gastrourinary: Th e abdom in al exam in ation sh ould be perform ed with patien t supin e with kn ees flexed. The physician sh ould assess for organom egaly, m asses, abdom in al disten sion , or ten dern ess. A m ale testicular exam in ation is n ot routin e but m ay be in dicated if the patient discloses a history of undescended or absen t testicle, pain , swellin g, m ass, or h ern ia. Musculoskeletal: Th e m usculoskeletal exam ination sh ould screen for m uscular or bone abnorm alities and reassess prior in juries. Th e n eurological exam in ation m ay be in tegrated in to th is portion of th e evaluation an d any un explain ed weakn ess, paresth esias, or focal deficits in dicate furth er workup. For th e gen eral participan t, a 14-point m usculoskeletal screening exam ination m ay be perform ed (Table 9.1). More elaborate join t-specific an d sport-specific exam in ation techniques m ay be used to augm en t th e m usculoskeletal exam in ation , especially in the event of a previous injury. All positive fin dings necessitate m ore detailed evaluation to preven t new injuries and en sure th at prior in juries an d con dition s h ave been fully reh abilitated prior to participation .

Clearance to Play Th e culm in ation of th e preparticipation evaluation is th e decision on clearan ce to play. Aphysician m ust carefully review all elem ents of the preparticipation evaluation to determ in e wh eth er participation is safe both for ath letes an d th eir team m ates in th e con text of th e sport in wh ich th ey will be participatin g. As th e physical dem an ds an d degree of con tact vary am on g sports, th e Am erican Academy of Pediatrics h as classified sports on th e basis of con tact (Table 9.2). An ath lete precluded from en gagin g in a h eavy-con tact sport m ay be allowed to participate in a lim ited or noncon tact sport. Treatable con dition s sh ould be addressed expeditiously an d reassessed prior to clearan ce. On ce all issues are reviewed, th e physician should subm it the final decision th at th e ath lete m ay participate with out restrictions, participate only after undergoing further evaluation or reh abilitation , participate with restriction s, or m ay n ot participate in th e specific sport because of clearly defin ed disqualifyin g con dition s. In th e even t th at th e ath lete an d physician do n ot agree about clearan ce issues, a written con sen t or legal waiver sign ed by th e ath lete an d th e paren t sh ould be obtain ed. A second opinion m ay also be sought by the ath lete.

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TABLE 9.1

THE 14-POINT MUSCULOSKELETAL SCREENING EXAMINATION Examination

Assessment

1. Stand facing examiner 2. Look at ceiling, floor, and over both shoulder and touch ears to shoulders 3. Shrug shoulders against resistance 4. Abduct shoulders against resistance 5. Full internal and external rotation of shoulders 6. Flex and extend elbows 7. Pronate and supinate 8. Spread fingers, clench fist 9. Stand with back to examiner 10. Extend back with knees straight 11. Flex back with knees straight 12. Examine lower extremities; contract/relax quadriceps 13. “Duck walk” four steps 14. Stand on toes, then on heels

General appearance, habitus, symmetry Cervical spine range of motion Trapezius strength Deltoid strength Shoulder range of motion Elbow range of motion Elbow and wrist range of motion Hand/finger range of motion; deformities Symmetry of trunk, upper extremities Pain suggests spondylolysis or spondylolisthesis Thoracic and lumbar spine range of motion; curvature; hamstring flexibility Symmetry and alignment of lower extremities Hip, knee, ankle range of motion, strength, balance Symmetry, calf strength, balance

(Adapted from McKeag D, Moeller JL, eds. American College of Sports Medicine’s Primary Care Sports Medicine. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2007.)

TABLE 9.2

CLASSIFICATION OF SPORTS BY CONTACT Contact/Collision

Limited Contact

Noncontact

Basketball Boxing Cheerleading Diving Extreme sports Field hockey Football, tackle Gymnastics Ice hockey Lacrosse Martial arts Rodeo Rugby Skiing, downhill Ski jumping Snowboarding Soccer Team handball Ultimate Frisbee Water polo Wrestling

Adventure racing Baseball Bicycling Canoeing or kayaking (white water) Fencing Field events High jump Pole vault Floor hockey Football, flag or touch Handball Horseback riding Martial arts Racquetball Skating Ice In-line Roller Skiing Cross-country Water Skateboarding Softball Squash Volleyball Weight lifting Windsurfing or surfing

Badminton Bodybuilding Bowling Canoeing or kayaking (flat water) Crew or rowing Curling Dance Field events Discus Javelin Shot put Golf Orienteering Power lifting Race walking Riflery Rope jumping Running Sailing Scuba diving Swimming Table tennis Tennis Track

(From Rice SG. American Academy of Pediatrics Council on Sports Medicine and Fitness: medical conditions affecting sports participation. Pediatrics. 2008;121(4):841–848.)


GAME COVERAGE

169

TABLE 9.4

Preparedness Preparation for gam e-day m ust take place lon g before th e first wh istle. Th e physician sh ould be in com m un ication with th e adm in istration an d ath letic train in g staff about all issues pertaining to the health and safety of the athletes. Th e respon sibilities of th e m em bers of th e h ealth care team sh ould be clearly defined, as well as th e chain of com m an d for gam e-day issues such as clearance to play, em ergencies, environm ental con cern s, and playing condition s. An efficien t an d reh earsed em ergen cy respon se plan sh ould be in place prior to th e start of th e season an d sh ould be verified with the athletic trainer an d em ergency person nel prior to each practice an d gam e. Th e establish m en t of a network of oth er health care providers in cluding prim ary care providers, specialists, and athletic trainers facilitates prompt treatm en t an d th orough follow-up. Th e physician coverin g a sportin g even t from th e sidelines should be fam iliar with the com m on condition s an d injuries th at arise from participation and should be prepared for all poten tial causes of on -field em ergen cies (Table 9.3). The m edical equipm ent an d supplies available on the sideline should consist of gen eral m edical essen tials and reflect the risks specific to the sport. Con tact sports such as football require consideration for im pact injuries, whereas endurance sports such as long-distance run n ing necessitate treatm ent strategies for fatigue an d dehydration . Supplies for sport-specific protective equipm en t such as the face m ask rem oval tool for football helm ets sh ould be readily available. The Am erican College of Sports Medicin e provides recom m en dation s for con ten ts of the m edical bag and on-site m edical supplies (Tables 9.4 an d 9.5).

RECOMMENDED CONTENTS OF A MEDICAL BAG ■ ■ ■ ■ ■ ■ ■ ■

■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■

Airway Alcohol/povidone–iodine swabs Bandage scissors, bandages, sterile/nonsterile, Band-aids Blood pressure cuff Cricothyrotomy kit Dental kit (e.g., cyanoacrylate, Hank solution) Epinephrine 1:1,000 in a prepackaged unit Eye kit (e.g., blue light, fluorescein stain strips, eye patch pads, cotton tip applicators, ocular anesthetic and antibiotics, contact remover, mirror) Flashlight Gloves Large bore (14–16 G) Angiocath for tension pneumothorax List of emergency numbers Local anesthetic/syringes/needles Mouth-to-mouth mask Nasal packing material Oto-ophthalmoscope Prescription pad Rectal thermometer Reflex hammer Short-acting β -agonist inhaler Skin staple applicator Small mirror Stethoscope Supplemental oral and parenteral medications Suture set/steri-strips Tongue depressors Topical antibiotics Wound irrigation materials (e.g., sterile normal saline, 10–50 cc syringe)

TABLE 9.5

ON-SITE MEDICAL SUPPLIES

TABLE 9.3

POTENTIAL ON-FIELD EMERGENCIES Traumatic

Medical

Head injury Spinal cord injury Cardiac tamponade Cardiac contusion Commotio cordis Hemothorax Tension pneumothorax Pulmonary contusion Flail chest Splenic rupture Ruptured viscus Fracture Dislocation Blood loss

Cardiac event Cerebrovascular accident Bronchospasm Anaphylaxis Pulmonary embolism Hyperventilation Spontaneous pneumothorax Hypoglycemia Hyponatremia Dehydration Heatstroke Hypothermia Lightning Drug/medication overdose

■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■

ACLS drugs and equipment Automated external defibrillator Blanket Cervical collar Crutches Extremity splints Face mask removal tool (for sports with helmets) Ice Ice immersion for events with risk of heat illness Mouth guards Oral fluid replacement Plastic bags Sideline concussion assessment protocol Sling psychrometer and temperature/humidity activity risk chart Slings Spine board and attachments Tape cutter Telephone

170


A

B

C

D Figure 9.1 (A-D) The logroll technique should be used when spine injury is suspected. (Reprinted

with permission from Garrett WE, Kirkendall DT, Squire DL. Principles and Practice of Primary Care Sports Medicine. Philadelphia, PA: Lippincott Williams & Wilkins, 2000.)

Approach to the Injured Athlete When an athlete goes down durin g play, the initial assessm en t sh ould take place im m ediately on th e field. Serious in jury m ust be completely excluded before m ovin g th e ath lete or rem ovin g any equipm en t. In th e even t of serious in jury, basic life support protocol, in cludin g a prim ary survey, sh ould be in itiated to m an age poten tially life-threaten ing conditions. Cervical im m obilization should be m aintained un til spin al cord in jury h as been ruled out, especially if th e ath lete was in volved in a collision or dem on strates n eurological deficits or altered m en tal status. A spin e in jury sh ould be presum ed in all un conscious patients. The prone ath lete m ay be logrolled to th e supin e position (Fig. 9.1). In football players, the face m ask should be rem oved as soon as possible to obtain access to th e airway, but th e h elm et absolutely m ust n ot be rem oved un til cervical spin e in jury is excluded (Fig. 9.2). If th e prim ary survey reveals any con cerning issues or if the athlete is unstable, the prearran ged em ergen cy respon se plan sh ould be activated prom ptly an d the athlete should be transported to a h ospital. The predom inan ce of injuries sustained on the field of play are n ot life-th reaten in g an d do n ot n ecessarily m erit such attention. In m ost cases, on ce serious in jury h as been excluded an d after a focused exam in ation , th e player m ay be h elped off th e field so th at play can resum e. Evaluation of th e in jury an d a com plete secon dary survey m ay th en

proceed in a m ore con trolled settin g on th e sidelin e. In juries sh ould be fully evaluated an d treated in th e con text of th e sport before allowin g reen try in to th e gam e. Th e team physician sh ould be in volved in all in juries or con dition s wh ere th e ability to participate is in question . Provision al m anagem ent such as bandaging or taping m ay allow return to play, but the injured player should be reassessed in sport-specific activity before final clearan ce. Decisions about participation should be clearly com m unicated to the player an d coach in g staff to preven t any con fusion . Any athlete wh o expresses h esitan cy about returning to play sh ould be h eld out un til concerns are addressed. All in juries and conditions should be docum ented so that they receive appropriate follow-up an d reh abilitation, and the player’s fam ily an d prim ary care provider sh ould be in form ed an d involved in decisions pertaining to continuing care.

COMMON ATHLETIC INJURIES Th e kin etic en ergy in h eren t to sports puts th e body at risk of in jury. Collision with an oth er player is respon sible for the m ajority of significant injuries sustained in sports, but oth er objects such as th e groun d, goalposts, walls, an d stan ds m ay inflict h arm as well. Noncontact injury m ech an ism s are pervasive regardless of sport an d represen t a larger


A

171

B

Figure 9.2 (A-C) A bolt cutter or face mask removal tool should be used

C

to remove the face mask as soon as possible to provide access to the player’s airway. (Reprinted with permission from Garrett WE, Kirkendall DT, Squire DL. Principles and Practice of Primary Care Sports Medicine. Philadelphia, PA: Lippincott Williams & Wilkins, 2000.)

proportion of train in g an d practice in juries th an in -gam e injuries. The lower extrem ity accounts for m ore than h alf of all sports-related in juries, with th e an kle or kn ee represen ting the m ost frequently injured joint. The distribution of in jury durin g com petition an d train in g by body part as reported by th e Nation al Collegiate Ath letic Association is illustrated in Figure 9.3.

HEAD INJURIES More than 300,000 sports-related head injuries were treated in U.S. em ergency departm ents in 2007, with cycling an d football comprising the m ost frequently implicated sports. The risk of head injury increases with the am oun t of en ergy to wh ich an ath lete is exposed. Despite rule m odifications and advances in helm et design and other protective equipm en t, th e force of im pact seen in som e sports such as football, boxing, and rugby approaches that of m otor vehicle accidents. Any athlete who exhibits sign s an d symptom s to in clude h eadach e, loss of con sciousn ess, altered m en tal status, cran ial nerve dysfun ction , or worsening symptom s sh ould be considered to have a significant traum atic brain injury and should undergo a thorough neurological evaluation alon g with serial exam in ation s.

Concussion Concussion is the m ost com m on head injury sustained by athletes and is ch aracterized by a transient posttraum atic impairm ent of cerebral neural function. Generally, th e result of a direct blow to th e h ead eith er by an oth er player, an object, or th e groun d, in itial sign s an d symptom s of concussion m ay in clude loss of consciousness, con fusion , am n esia, vision or balan ce dysfun ction , n ausea, or h eadache wh ile persistent effects include m em ory or cogn itive deficits, sleep disturban ce, an d em otion al lability. Frequen tly, team m ates m ay iden tify a player wh o is dem on stratin g con cussive sym ptom s. Th e sidelin e in terview is the m ost effective m ethod of detecting impairm ent, and the Standardized Assessm ent of Concussion (SAC) perm its docum entation of symptom s for serial exam ination (Fig. 9.4). Th e goal of m an agem en t is to m in im ize postcon cussive syndrom e sym ptom s and prevent secon d-impact syndrom e. Postcon cussive syn drom e is ch aracterized by persisten ce of con cussion symptom s secon dary to cerebral m etabolic derangem ents and neurotransm itter dysfunction. Athletes with prolonged postconcussive syn drom e sh ould n ot be allowed to participate in any exertional activities and m ay require neuroim aging or expert con sultation . Second-impact syndrom e is a rare but catastroph ic sequela

172


Percentage of Injuries (Games)

Percentage of Injuries (Practices) Other, 2%

Other, 5% Head/Neck, 13%

Head/Neck, 10%

Lower Extremity, 54%

Upper Extremity, 18%

Trunk/Back, 13%

Lower Extremity, 54%

Upper Extremity, 21%

Trunk/Back, 10%

B

A Figure 9.3 (A) Percentages of injuries by body part during competition for 15 sports, National

Collegiate Athletic Association 1988–2004. (B) Percentages of injuries by body part during training/practice for 15 sports, National Collegiate Athletic Association 1988–2004. (Data from Hootman JM, Dick R, Agel J. Epidemiology of collegiate injuries for 15 sports: summary and recommendations for injury prevention initiatives. J Athl Train. 2007;42(2):311–319.)

Figure 9.4 Standardized Assessment of Concussion testing permits documentation of symptoms

for serial examination. (Reprinted with permission from McCrea M. Standardized mental status testing on the sideline after sport-related concussion. J Athl Train. 2001;36(3):274–279.)


173

TABLE 9.6

CANTU AND AMERICAN ACADEMY OF NEUROLOGY GRADING SYSTEMS FOR CONCUSSION Grade

Cantu

1 (Mild)

■ ■ ■ ■

2 (Moderate)

■ ■ ■

■

3 (Severe)

■ ■

■

■

AAN

No LOC, PTA < 30 min, PCS < 24 h First concussion: RTP if asymptomatic for 1 wk Second concussion: RTP in 2 wk if asymptomatic for 1 wk Third concussion: Terminate season; RTP next season if asymptomatic LOC < 1 min or PTA ≥ 30 min or PCS ≥ 24 h and < 7 d First concussion: RTP if asymptomatic for 2 wk Second concussion: RTP in 1 mo if asymptomatic for 1 wk Third concussion: Terminate season; RTP next season if asymptomatic LOC ≥ 1 min or PTA ≥ 24 h or PCS ≥ 7 d First concussion: No RTP for at least 1 mo; must be asymptomatic for > 1 wk Second concussion: Terminate season; RTP next season if asymptomatic Third concussion: Consider no further contact sports

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■

■ ■

■ ■

■

No LOC, transient confusion; symptoms resolve in < 15 min. First concussion: RTP if asymptomatic for 15 min Second concussion: RTP if asymptomatic for 1 wk No LOC, transient confusion; symptoms persist for > 15 min. First concussion: RTP if asymptomatic for 1 wk Second concussion: RTP if asymptomatic for 2 wk Any LOC First concussion: Transport to hospital; if LOC brief, may RTP if asymptomatic for 1 wk; for prolonged LOC (> 1 min), RTP if asymptomatic for 2 wk Second concussion: RTP if asymptomatic for 1 mo

AAN, American Academy of Neurology; LOC, loss of consciousness; PTA, posttraumatic amnesia; PCS, postconcussive syndrome; RTP, return to play. (Adapted from Patel DR, Greydanus DE, Luckstead EF Sr. The college athlete. Pediatr Clin North Am. 2005;52(1):25–60, vii–viii.)

of recurren t h ead traum a prior to resolution of con cussion symptom s distin guished by a secondary loss of cerebrovascular autoregulation that results in increased intracranial pressure from excessive blood flow. A preven table con dition, second-impact syndrom e is associated with 50% m ortality an d 100% m orbidity, typically from cerebral edem a an d h erniation, which m ay result from seem ingly m inor con tact. Given th e poten tial complication s, clearin g an ath lete to play after a con cussion presen ts a difficult clin ical decision . Regardless of h ow benign they appear, all concussions require an observation period of at least 15 to 20 m in utes. Durin g th is tim e, th e ath lete sh ould be m on itored closely, an d deterioration of m ental status, developm ent of focal deficits, seizure activity, or vital sign lability sh ould prompt im m ediate transfer to a h ospital. If the athlete appears to be improving, th e physician should then repeat the SAC evaluation lookin g carefully for m em ory or cogn ition deficits. No ath lete actively dem on stratin g symptom s sh ould be allowed to play. The presen ce of a headach e sh ould n ot be discoun ted. Return to play m ay be con sidered after com plete resolution of symptom s after th e period of observation, and the ath lete should be exerted prior to reentry to en sure th at n o symptom s reem erge. If symptom s recur later in th e gam e, the player should be rem oved from play and be closely observed. More severe con cussion s such as th ose with loss of con sciousness or persistent symptom s typically disqualify th e athlete from participation for th e rem ainder of the day of injury, and return to play is based on severity and duration of symptom s. Multiple grading system s including the

Can tu an d Am erican Academy of Neurology gradin g system s h ave been developed to classify th e severity of a con cussion and provide a general outline on when to allow return to play (Table 9.6). Accurately gradin g a con cussion acutely m ay be difficult, an d each ath lete sh ould be m an aged on an in dividual basis. Regardless of th e grade, con cussions associated with abn orm al computed tom ography (CT) or m agn etic reson an ce im agin g (MRI) scan s sh ould preclude return to play for th e rem ain der of th e season .

Intracranial Hemorrhage Clinical deterioration and developm ent of focal deficits m ay be m anifestations of severe traum atic brain injury. A direct blow to the h ead m ay cause a cerebral contusion, in which cerebral parenchym al blood vessels are violated, resultin g in bruisin g an d in tern al bleedin g. Patien ts m ay sh ow focal sym ptom s such as partial paralysis, cranial nerve involvem ent, or labile vital signs. A high-velocity impact to th e temple m ay fracture th e skull, disruptin g th e m iddle m eningeal artery to cause an epidural hematoma. In this injury, blood accum ulates in th e poten tial space between th e skull and th e dura m ater, and the ch aracteristic clinical sequen ce begin s with a brief loss of con sciousn ess, followed by a lucid interval, and culm inates in rapid deterioration of n eurologic function. Th e bridgin g vein s traversin g the subdural space are vuln erable to acceleration -/ deceleration type forces. An injury to these vessels results in a subdural hematoma, an d neurological consequences m ay appear im m ediately or develop over the course of several days or weeks. Sym ptom s are gen erally progressive an d ran ge from

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FACIAL INJURY

Figure 9.5 Types of intracranial hemorrhage: epidural hematoma

occurs when blood accumulates in the epidural space usually due to injury of the middle meningeal artery. Subdural hematoma results from damage to bridging veins between the brain and dura. Intracerebral hematoma occurs deep within the brain. (Reprinted with permission from Baker CL, Flandry F, Henderson JM. The Hughston Clinic: Sports Medicine Book. Philadelphia, PA: Williams & Wilkins, 1995.)

m ild alteration in level of con sciousn ess to com a or m ajor focal neurological deficit. Suspected in tracranial bleeding m an dates im m ediate tran sport to a h ospital wh ere furth er evaluation an d treatm en t sh ould take place (Fig. 9.5).

Because of th e abun dant vascularity of th e face, facial in juries are frequen tly associated with profuse bleedin g an d sign ificant swellin g. Closed head injury an d cervical spine injury should be considered with all facial traum as. Facial laceration s are com m on and bleeding m ay be con trolled with direct pressure. Un iversal precaution s sh ould be m ain tain ed wh en m an agin g any bleedin g. Followin g th orough irrigation, sm all lacerations m ay be closed with an adhesive bandage, whereas larger wounds m ay require stitches. Sim ple an terior n asal bleeds in volvin g disruption of th e Kiesselbach ven ous plexus in the anterior nose m ay be controlled with direct pressure or a vasoconstrictive nasal spray such as oxym etazoline or phenylephrine. Posterior epistaxis in wh ich brisk n asoph aryn geal bleedin g occurs from injury to the sphenopalatine artery or other larger vessel m ay n ot respond to nasal spray an d warrants n asal packing and transfer to the hospital for furth er m anagem en t (Fig. 9.6). Nasal fractures compose th e m ajority of facial fractures and usually are associated with epistaxis, soft tissue swellin g, septal h em atom a, and obvious nasal deform ity. Depen din g on th e degree of displacem en t, con servative or surgical m anagem en t m ay be indicated. Eye injuries also occur frequently in sports and m ay result in lon g-term m orbidity. Sports-related eye injuries are a leading cause of adolescen t blin dn ess, an d 90% of these injuries m ay be avoided with protective eyewear. Sign ifican t eye in jury m ay presen t with ph otoph obia, partial or com plete vision loss, double vision , or eye pain . Corneal abrasion m ay occur with direct traum a such as a finger to the eye

Figure 9.6 Vascularity of the nasal cavity.

(Reprinted with permission from Baker CL, Flandry F, Henderson JM. The Hughston Clinic: Sports Medicine Book. Philadelphia, PA: Williams & Wilkins, 1995.)


Figure

175

9.7 Fluorescein-stained central corneal abrasion.

(Reprinted with permission from Greenberg MI, Hendrickson RG, Silverberg M, et al., eds. Greenberg’s Text-Atlas of Emergency Medicine. Philadelphia, PA: Lippincott Williams & Wilkins, 2004.)

(Fig. 9.7). Ath letes m ay complain of photophobia an d sen sation of a foreign object. Diagnosed with fluorescein stain, athletes with significant abrasions m ay require antibiotics an d an eye patch. Periorbital contusion or “black eye’’generally m ay be treated with con servative m an agem en t in volving ice to control swellin g and observation. Athletes wh o sustain a black eye sh ould un dergo a th orough oph thalm ologic exam ination to ensure that the eye is not in jured an d th e orbit is n ot fractured. More serious eye in juries sh ould be referred to an oph th alm ologist. Th e cauliflower ear, com m on ly seen in boxers an d wrestlers, represen ts th e con sequen ces of recurren t ear traum a (Fig. 9.8). Auricular hem atom as develop between the skin and underlying cartilage and should be treated with ice to reduce swellin g. Severe swellin g m ay cause cartilage breakdown, and fluid accum ulation m ay n ecessitate aspiration. Mouth guards sh ould be worn by ath letes participatin g in contact sports to prevent dental injury. In the event of den tal in jury, bleedin g m ay be con trolled with direct pressure. Loose teeth should be gently pushed back in to their norm al position, an d fractured or avulsed teeth sh ould be located an d placed in to Han k solution , m ilk, or sterile salin e. An avulsed tooth should be han dled by the crown to preven t root in jury. Ath letes wh o sustain a den tal in jury sh ould be referred to a den tist for further care.

SPINE According to the National Spinal Cord Injury Statistical Cen ter, sports-related spinal cord injuries accounted for approxim ately 7.4% of all spin al cord in juries sin ce 2005, with alm ost 25% of spinal cord injuries in patients younger than 15 years an d 15% of those in patients between 15 and 30

Figure 9.8 Cauliflower ear. (Reprinted with permission from

Greenberg MI, Hendrickson RG, Silverberg M, et al., eds. Greenberg’s Text-Atlas of Emergency Medicine. Philadelphia, PA: Lippincott Williams & Wilkins, 2004.)

years. The in ciden ce of catastrophic spinal cord injuries in sports ranges from 0.5 to 2.5 in 100,000. Diving, bicyclin g, and football are am ong th e sports m ost com m only implicated in spin al cord in jury, an d th e cervical spin e is th e m ost frequently involved.

Cervical Spine Neck pain , focal n eurological deficits, loss of con sciousn ess, or abn orm al reflexes m ay sign ify a spin al cord injury and should be system atically docum ented. Spine precautions con sisting of in-line im m obilization an d logrolling m ust be m aintain ed for all unconscious athletes an d all th ose suspected of sustain in g a cervical spin e in jury. Players sh ould n ot be tran sported un til proper im m obilization is in place. Cervical collars, backboards, and stretchers are essen tial equipm en t an d sh ould be readily available for any sportin g even t in wh ich a spinal cord injury is a possibility. Th e h elm et of football players m ust n ot be rem oved. Rem oving a football helm et without the sh oulder pads produces un acceptable m otion in th e cervical spin e an d m ay com prom ise th e cord. Th e player sh ould be tran sported to the hospital, im m obilized on a spine board with helm et and pads in place. The face m ask should always be rem oved from the helm et as soon as possible to ensure access to the airway. If the airway needs to be secured, the cervical spine m ay be protected with the jaw-thrust and ch in-lift m aneuver. Th e head-tilt m an euver should be avoided. A m ethodical radiograph ic an alysis sh ould begin with anteroposterior, lateral, and oblique plain radiographs an d

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1

2

3

4

A

B Figure 9.9 The lateral cervical spine radiograph should be examined for alignment and evidence of instability. (Reprinted with permission from Brant WE, Helms CA, eds. Fundamentals of Diagnostic Radiology. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2007.)

Figure 9.10 Instability is indi-

cated by translation of more than 3.5 mm (distance between A and B) or junctional kyphosis of more than 11 degrees (difference between angle C and D). (Reprinted with permission from Baker CL, Flandry F, Henderson JM. The Hughston Clinic: Sports Medicine Book. Philadelphia, PA: Williams & Wilkins, 1995.)


A

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B

Figure 9.11 Spear tackler’s spine involves cervical stenosis and

C

m ust include the cervicothoracic junction (Fig. 9.9). Vertebral deform ity, soft tissue swellin g, loss of lordosis, stepoffs, or splayin g of posterior elem en ts sign ify spin al in jury. In stability is in dicated by jun ction al kyph osis of m ore th an 11 degrees or anteroposterior translation greater than 3.5 m m (Fig. 9.10). The space available for the cord between C3 and C7 averages approxim ately 17 m m in adults. Relative and absolute stenosis are present if the canal narrows to less th an 13 m m an d 10 m m , respectively, an d represen ts a relative or absolute contraindication to contact sports depen din g upon presen ce of sym ptom s. Spear tackler’s spin e is an entity that involves cervical stenosis and loss of lordosis typically seen in football players an d proh ibits participation in con tact sports (Fig. 9.11). Fractures m ay be fur-

loss of lordosis and is associated with increased risk of spinal cord injury. This condition prohibits contact sports. (Reprinted with permission from Garrett WE, Speer KP, Kirkendall DT, eds. Principles and Practice of Orthopaedic Sports Medicine. Philadelphia, PA: Lippincott Williams & Wilkins, 2000.)

ther elucidated by CT scans with reconstruction s, and an MRI study to assess soft-tissue, ligam en tous, or disc path ology is in dicated for n eurological deficits, radiculopathy, or myelopathy. A referral to a spine surgeon is in dicated for any abn orm alities. Guidelin es for participation in sports for a n um ber of cervical spine conditions are outlined in the Torg guidelines (Table 9.7).

Minor Neck Injuries Th e m ajority of cervical spin al cord in juries are self-lim ited sprains characterized by persistent n eck pain an d lim ited range of m otion with no neurological symptom s.

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TABLE 9.7

GUIDELINES FOR ATHLETES WITH CERVICAL SPINE ABNORMALITIES No Contraindication to Contact Sports ■ Asymptomatic cervical stenosis ■ Klippel–Feil type 2 anomaly with full range of motion with no evidence of instability ■ Spina bifida occulta ■ Healed, stable nondisplaced fractures without sagittal malalignment ■ Asymptomatic disc herniations treated conservatively in the past ■ After a healed one-level anterior or posterior cervical fusion in asymptomatic patient Relative Contraindications to Contact Sports for Asymptomatic Patients ■ Cervical stenosis with one episode of cord neuropraxia ■ Prior upper cervical spine fracture ■ Healed, stable minimally displaced fracture of the body without sagittal malalignment or canal compromise ■ Healed, stable fracture of the posterior elements ■ Minimal residual facet instability after surgical or conservative treatment of cervical disc disease ■ After a healed two- or three-level cervical fusion Absolute Contraindications to Contact Sports ■ Cervical stenosis ■ With one episode of cord neuropraxia and MRI evidence of cord injury ■ With one episode of cord neuropraxia associated with instability or neurologic symptoms lasting for more than 36 h ■ With multiple episodes of cord neuropraxia ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■

Odontoid anomalies Atlantooccipital fusion Atlantoaxial instability Atlantoaxial rotatory fixation Certain Klippel–Feil anomalies Spear tackler’s spine Subaxial spinal instability Acute fracture of either the body or posterior elements Healed fracture with residual sagittal malalignment or canal compromise Continued pain, abnormal neurological findings, or limited motion from a healed cervical fracture Symptomatic acute soft or chronic disc herniation After any fusion in the presence of congenital stenosis

MRI, magnetic resonance imaging. (Adapted from Torg JS, Guille JT, Jaffe S. Injuries to the cervical spine in American football players. J Bone Joint Surg Am. 2002;84-A(1):112–122.)

Im m obilization with a cervical collar sh ould con tin ue un til resolution of acute sym ptom s at wh ich tim e dyn am ic flexion and exten sion radiographs m ay be obtained. Radiograph ic eviden ce of in stability warran ts furth er in vestigation of ligam en tous in jury with MRI. Treatm en t of sprains con sists of conservative m an agem en t in cludin g an ti-in flam m atories an d physical th erapy. An ath lete m ay return to play on ce symptom s subside if th ere are n o radiograph ic abn orm alities.

Stingers and Transient Quadriplegia Sports-related n eck in juries with self-lim ited n eurological symptom s include stin gers and transient quadriplegia. A temporary un ilateral upper extrem ity burn in g dysesth esia with associated m otor weakn ess, a stinger or burner is usually th e result of traction or direct traum a to th e brach ial plexus or m om en tary foram in al com pression of a nerve root from neck extension or lateral flexion (Fig. 9.12).

Figure 9.12 A stinger or burner may result from traction on the

brachial plexus. (Reprinted with permission from Fu FH, Stone DA, eds. Sports Injuries: Mechanisms, Prevention, Treatment. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2001.)


Approxim ately half of all collision-sports ath letes will experien ce a stin ger at som e poin t durin g th eir career. Th e typical complaint is a pain ful sensation th at radiates from the neck to fingertips after a lateral blow to neck or sh oulder. Th e effects of a stin ger are sh ort-lived, an d gen erally, return to play is perm issible if symptom s resolve. Persisten t or recurren t sym ptom s preclude from play an d require further workup. Transient quadriplegia is less com m on, affectin g approxim ately 1.3 in 10,000 athletes, but entails a m ore serious in jury th an a stin ger. Usually a result of hyperexten sion often accompanied by axial loading of the neck, tran sient quadriplegia is characterized by bilateral sym ptom s that m ay include burning, paresthesias, loss of sensation, an d/or weakn ess in the arm s and/ or legs. The severity of symptom s m ay range from m ild paresthesias to complete paralysis an d m ay persist for up to 36 h ours. Ath letes with transient quadriplegia, especially those with symptom s for m ore than 36 hours, should receive im aging of the cervical spine. All athletes with symptom s of cord neuropraxia should be presum ed to h ave a spin e in jury an d spin e precautions should be m ain tain ed un til appropriate evaluation has taken place. Determ in ation of return to play for th ese types of injuries presen ts a ch allenge to the sports physician . No athlete should be allowed to play with neurological deficit, painful range of m otion of neck, or pain on axial loading of spine. Instability, disc disease, congenitally fused segm ents, an d canal stenosis predispose athletes to transient quadriplegia, and careful consideration of th ese poten tially dan gerous con dition s sh ould be m ade before allowing return to play.

Thoracolumbar Spine Th oracolum bar spin e in juries an d con dition s also affect the athletic population. Wh ile the m ajority of these injuries are m in or, severe in juries m ay occur, an d proper m an agem ent is important to preven t further injury. The thoracolum bar spin e m ay be con trolled with logrollin g an d placin g th e ath lete on a backboard. Neurological fun ction m ay be assessed by exam ining m otor and sensory function in the extrem ities, and deficits prompt m ore th orough evaluation . Th e m ost com m on etiology of low back pain is lumbar strain, a condition characterized by point tenderness in th e paraspin al m usculature of th e low back an d pain with m otion. Strains generally respond to rest, activity m odification , therapy, and symptom atic treatm ent. Radicular symptom s m ay develop if a nerve root is compressed or irritated, usually from a bulging disc. Low back pain with radiculopathy also tends to improve with conservative treatm en t. Athletes with persisten t or progressive symptom s sh ould be referred to a spin e surgeon . In som e ath letes such as gym n asts an d football players, repetitive lum bar hyperexten sion produces impaction

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Figure 9.13 Spondylolysis (A) is a stress fracture of the pars

interarticularis that may result from repetitive hyperextension of the lumbar spine. Spondylolisthesis (B), or slippage of the vertebra, may occur with bilateral pars fractures. (Reprinted with permission from Anderson MK, Hall SJ, eds. Sports Injury Management. Baltimore, MD: Williams & Wilkins, 1995.)

of th e in ferior articular facet upon th e pars in terarticularis, leadin g to spondylolysis (Fig. 9.13). In this con dition in which a defect develops in the pars, the athlete m ay com plain of low back pain exacerbated by exten sion an d paraspin al m uscle spasm an d h am strin g tigh tn ess. Bilateral pars defects m ay lead to spondylolisthesis or slippage of th e vertebra. Diagnosis is con firm ed by oblique radiographs of the lum bar spine or sin gle-photon em ission CT scan. Ath letes with suspected spon dylolysis or spon dylolisth esis sh ould be referred to a spin e surgeon .

THORACIC INJURY Ath letes in volved in h igh -speed or con tact sports are vuln erable to in juries of th e ch est wall an d in trath oracic organs. Rib fractures con stitute th e m ajority of ch est wall injuries, m ost com m only resulting from blunt traum a, alth ough n on con tact an d overuse m ech an ism s m ay also cause rib fracture. Usually in volvin g th e m idaxillary region of ribs 4 th rough 9, rib fractures are associated with local pain an d ten dern ess an d pain on deep in spiration . An isolated rib fracture typically m ay be treated expectantly, but stern al fractures, pn eum othorax, flail chest, an d fractures of th e first rib con stitute m ore serious in jury an d require further m anagem ent. Although protected by the chest wall, the intrath oracic organ s are vuln erable to h igh -en ergy traum a. Cardiac con tusion m anifests as a dull ch est pain after blun t chest wall traum a an d should be evaluated by electrocardiography due to th e risk of associated dysrhyth m ia. Commotio cordis is a leth al ven tricular arrhyth m ia resultin g from a direct blow to the chest, precisely corresponding to the repolarization ph ase of th e con tractin g h eart. Most com m on ly described in youth baseball, com m otio cordis m ust be treated with cardiopulm on ary resuscitation an d early defibrillation to preven t alm ost certain death . Basic life support train in g an d accessibility of autom ated external defibrillators are vital to preven tin g cardiac-related m orbidity an d m ortality.

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A

B

Figure 9.14 Right-sided pulmonary contusion as demonstrated on chest radiograph (A), and axial

computed tomography scan (B). (Reprinted with permission from Greenberg MI, Hendrickson RG, Silverberg M, et al., eds. Greenberg’s Text-Atlas of Emergency Medicine. Philadelphia, PA: Lippincott Williams & Wilkins, 2004.)

Acute onset of shortness of breath m ay signify pulm on ary injury. Transient dyspnea after a blow to the chest or abdom en is due to a brief diaph ragm atic spasm th at spon tan eously rem its. This is referred to by th e colloquial ph rase “gettin g th e win d kn ocked out of you’’an d gen erally requires n o furth er m an agem en t on ce symptom s subside. Pulmonary contusion m ay occur in blun t ch est wall traum a an d often accompany rib fractures (Fig. 9.14). Pulm onary contusions resolve with tim e, but the physician should be aware of possible com plication s such as pn eum on ia or respiratory distress. Sudden on set of dyspn ea, pleuritic ch est pain , an d decreased breath soun ds are ch aracteristic of pneumothorax, a poten tially serious con dition in wh ich the lun g partially or completely collapses. Pneum othorax m ay be the result of impact or m ay occur spon taneously, an d ath letes exhibitin g symptom s should be placed on oxygen an d tran sported to a h ospital for m an agem en t. Tension pneumothorax is a m edical em ergency characterized by dyspn ea, tachycardia, n eck vein disten sion , an d trach eal deviation . Decreased breath sounds and tympany to percussion identify the affected side. If suspected, the ath lete m ay decompensate quickly, an d large-bore needle decompression into the second intercostal space at the m idclavicular line of th e affected side m ay be life-savin g.

ABDOMINAL INJURY A sudden in crease in in tra-abdom in al pressure from a direct blow m ay disrupt th e diaph ragm or in tra-abdom in al organ s (Fig. 9.15). Ath letes wh o sustain abdom in al traum a m ay in itially h ave a n orm al abdom in al exam in ation , an d serial exam inations for developm ent of tendern ess, rigidity,

Figure 9.15 Athletic collision may cause intra-abdominal injury.

Bleeding may be slow and symptoms may develop insidiously. (Reprinted with permission from Fu FH, Stone DA, eds. Sports Injuries: Mechanisms, Prevention, Treatment. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2001.)


an d distension m ay be required to detect a serious intraabdom in al in jury. A ruptured viscous is a surgical em ergen cy, an d an athlete who suffers a significant bowel injury needs to be tran sferred im m ediately to a h ospital for urgen t m an agem ent. The poor visceral sensory innervation delays on set of symptom s from intraabdom inal injury, and n on specific symptom s such as diffuse abdom inal pain , nausea, diarrh ea, or hypoten sion m ay appear in sidiously. Developm en t of such sym ptom s in th e con text of abdom in al traum a warrants further workup. Splenic injury presen ts with n ausea, left upper quadran t ten dern ess or referred left sh oulder pain (Keh r sign ) after a blow to th e abdom en . Sm all capsular laceration s m ay heal with out becom in g clinically apparent, but large laceration s m ay progress to splen ic rupture, resultin g in in traabdom inal hem orrhage and hem odynam ic in stability. Splen ic en largem en t is a feature of m on on ucleosis, an d athletes with active or resolving m on onucleosis sh ould be restricted from con tact un til th e spleen h as return ed to n orm al size. Righ t upper quadran t pain with radiation to th e righ t sh oulder m ay in dicate a hepatic injury an d sh ould be evaluated with liver function tests and CT. Perium bilical or back pain alon g with n ausea m ay be m an ifestation s of pancreatic injury and patien ts should be m onitored closely for developm en t of pan creatitis. Positioned posteriorly in the abdom en, the kidneys are vulnerable to direct blows to the back. Renal contusion is usually accom pan ied by flan k ten dern ess an d gross or m icroh em aturia. Diagnosis is confirm ed by urinalysis, intraven ous pyelogram , or renal ultrasound. CT scan with con trast m ay be obtained to detect m ore serious in juries to the kidney such as lacerations, bleeding, or ureteral injuries. Exten sive bleedin g with ren al fracture or vascular pedicle injury requires urgent surgery. Because of the risk of kidney injury, ath letes with one kidney deserve special consideration wh en determ ining clearan ce to play.

MUSCULOSKELETAL INJURY Approxim ately 75% of injuries sustained in college athletics involve the extrem ities, with ankle sprain s accounting for alm ost 15% of all sports-related injuries. Evaluation of a suspected extrem ity injury should include in spection for deform ity, laceration s, abrasion s, bruisin g, swellin g, an d neurovascular status. Th e ran ge of m otion and stability of the involved joint should be n oted, and associated injuries sh ould be explored. Extrem ity injuries m ay occur in con jun ction with spin al cord in juries, an d cervical im m obilization and spine precaution s should be m aintained until spinal cord injury is excluded. Soft tissue in juries com pose the overwhelm ing m ajority of m usculoskeletal extrem ity injuries sustain ed in sports. For m ost of these in juries,

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in itial m an agem en t in volves protection , rest, ice, compression , an d elevation (PRICE).

Orthopaedic Emergencies Few extrem ity injuries constitute em ergencies, but these sh ould be identified an d addressed promptly when assessing a down ed athlete. Fractures of the pelvis or fem ur, fractures associated with vascular injuries, penetratin g traum a, and open fractures m ay jeopardize hem odynam ic stability or th reaten an extrem ity, an d th e physician sh ould im m ediately provide provisional treatm ent while the em ergen cy respon se plan is initiated. Typically the result of a high-energy m echan ism , the physician should m aintain a high index of suspicion for con com itant head, spin e, in trathoracic, or intraabdom inal injury when evaluating th ese injuries. Vital sign s and th e con dition of the affected extrem ity should be m onitored closely, and th e athlete sh ould be tran sferred to a hospital as soon as possible. Active bleeding should be controlled with direct com pression an d elevation of th e in jured extrem ity. Un iversal precaution s sh ould be m ain tain ed wh ile treatin g a bleeding athlete. Open fractures should be irrigated copiously with salin e before dressin g an d splin tin g. Join t dislocation s sh ould be reduced as soon as possible to prevent n eurovascular comprom ise an d osteon ecrosis. Som e dislocation s, such as shoulder dislocations, m ay be reduced on the field acutely prior to onset of m uscle spasm . Irreducible dislocation s n ecessitate prompt tran sfer to a h ospital wh ere sedation an d m uscle relaxan ts m ay be adm in istered. A n eurovascular exam in ation before an d after reduction sh ould be docum en ted, an d ch an ges in pulses or n eurological status dem and urgent attention.

Compartment Syndrome Compartment syndrome occurs because of elevated pressure with in a fascial compartm en t th at atten uates blood flow and m ay occur following injury, with exercise, or a constricting bandage or splint. Involving the leg or forearm in m ost cases, compartm en t syn drom e is a clin ical diagn osis based on observed tigh tn ess of a com partm en t, paresth esias, pain on passive stretch of m uscles that traverse the com partm en t, an d pain out of proportion al to physical exam in ation fin din gs. Sym ptom s gen erally develop gradually, an d once diagn osed, em ergent fasciotomy is needed to preven t tissue n ecrosis. Pallor, paralysis, an d pulselessn ess are late sign s an d signify that dam age h as already occurred. Exertional compartment syndrome is activity-related pain th at occurs wh en exercisin g m uscle swells, becom in g con stricted to th e poin t of ischem ia by the unyielding fascia. Pain is gen erally quickly alleviated by rest. Measurem en t of compartm en t pressures before an d after exercise is diagn ostic, an d treatm en t involves fasciotomy of th e affected com partm en ts. Com partm en t pressures of m ore th an

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15 m m Hg at rest, m ore than 30 m m Hg 1 m inute after exercise, an d/ or m ore th an 20 m g Hg 5 m in utes after exercises are considered diagn ostic of exertional compartm ent syn drom e.

Muscular Injury Muscles are in jured by direct traum a, overuse, or overstretch. A contusion is caused by direct impact, which com presses th e m uscle again st th e un derlyin g bon e. Most com m on ly affectin g th e an terior th igh an d biceps, con tusion s m ay be preven ted with appropriate paddin g an d usually respon d to con servative m an agem en t of a sh ort period of im m obilization followed by ran ge-of-m otion exercises an d stren gthen ing. Repeated traum a or inadequate reh abilitation m ay result in myositis ossificans, in which calcification develops in th e m uscle, resultin g in ectopic bon e form ation . Delayed-onset muscular soreness develops 24 to 72 hours after vigorous activity an d is m ost frequen tly seen at th e start of the training when th e ath lete is n ot accustom ed to in ten se exercise. This con dition is self-lim ited and pain m ay be alleviated with rest an d n on steroidal an ti-in flam m atory drugs (NSAIDs). Gradual onset of symptom s distin guishes m uscular soreness from muscular strain, wh ich is an overstretch in g in jury to the m uscle, characterized by im m ediate pain and loss of function. Ranging in severity from m ild disruption of m uscle fibers to com plete tears, strain s or “pulled m uscles’’m ost often affect the myotendinous junction of m uscles that cross two joints such as the ham strin gs or quadriceps an d during eccentric contraction. Symptom s include localized tenderness, swelling, weakness, an d painful m otion . Preven tion of strain s en tails adequate stretch in g an d conditioning, and treatm en t consists of PRICE. On ce the acute pain an d swellin g h as improved, emph asis sh ould be sh ifted to stren gth en in g an d reh abilitation . Rein jury is com m on despite seem ingly sufficient therapy, and chronic m uscle strain s m ay persist for several m on th s.

Ligamentous Injury Th e static stabilizers of join ts, ligam en ts m ay be disrupted un der excessive ten sion from extrem es in join t m otion . Minor dam age to the fibers of a ligam ent is designated a sprain an d is ch aracterized by local pain an d ten dern ess, swellin g, an d pain on join t ran ge of m otion . Th e m ost com m on ly sprained join t, the ankle is typically in jured wh en ath letes plan t th eir foot awkwardly an d roll or twist th e an kle. Treatm en t of m in or sprain s is symptom atic an d in cludes PRICE. Activity sh ould be restricted to allow the ligam ent to heal, a process th at m ay take up to 6 weeks. Protected ran ge of m otion is im plem en ted to preven t stiffn ess. Th e recurren ce rate after return to play is h igh due to atten uation of fibers an d comprom ise of joint proprioception. Athletes m ay benefit from wrapping or bracing th e injured joint. Partial or complete ligament tears represen t m ore severe in juries. In addi-

tion to pain and swelling around the joint, these injuries are associated with join t laxity or instability. Plain radiograph s sh ould be obtain ed to ch eck for osseous injury as avulsion fractures have a sim ilar clinical picture. Stress radiograph s or MRI m ay assist in diagn osis. Th e severity an d location of th e tear guide treatm en t. A m ore con servative approach m ay be appropriate if fiber con tin uity is m ain tain ed. Complete tears imply th at all fibers are disrupted, an d th e ligam en t m ay n ot h eal properly if th e en ds are n ot approxim ated. In gen eral, in traarticular structures such as th e an terior cruciate ligam en t (ACL) of th e kn ee will n ot h eal because of th e in effectiven ess of the fibrin clot in the intraarticular environm en t. Th ese ligam ents frequently require recon struction when torn. Extraarticular structures such as the m edial collateral ligam ent of the kn ee m ay heal with conservative m anagem ent. Th ese types of gen eralization s do n ot dictate treatm en t, an d each ath lete an d ligam en t in jury sh ould be evaluated in dividually. Factors such as th e join t in volved, severity of sym ptom s, sport played, and level of competition m ust be con sidered in developin g a m an agem en t strategy. Con servative therapy con sists of a period of im m obilization an d sym ptom atic treatm ent followed by therapy and rehabilitation . Surgical treatm en t in volves prim ary repair or recon struction usin g autograft or allograft. Return-to-play determ in ation sh ould be m ade on an in dividual basis an d sh ould take in to accoun t the resolution of symptom s an d the stren gth and stability of the joint.

Stress Fractures Stress fractures result from repetitive in sults to n orm al bon e, wh ich progressively disrupt in tern al trabeculae, even tually leadin g to cortical weakn ess. Th e tibia, m etatarsals, an d fibula of track-and-field ath letes and m ilitary recruits are m ost com m only involved (Fig. 9.16). This pattern of presen tation reflects th e path ophysiology beh in d th ese overuse in juries. Th e weigh t-bearin g bon es of en duran ce athletes sustain cyclic traum a with inadequate recovery. Th is repetitive stress accum ulates to overcom e th e capacity of the bone to rem odel. Upper extrem ity stress fractures m ay also occur in sports such as baseball and tennis, which expose th e bon es of th e arm s or h an ds to sim ilar types of recurren t loads. Stress fractures presen t with localized pain exacerbated by the offending activity and transiently relieved by rest. Pain m ay persist after cessation of activity and at night as th e fracture evolves. Plain radiographs are unreliable during the early stages of stress fracture but m ay show periosteal reaction , trabecular discon tin uity, or a lin ear ban d of sclerosis. Advan ced im agin g m odalities such as MRI or bon e scan are useful to establish a definitive diagn osis. Treatm en t generally entails activity m odification to avoid th e excessive forces upon th e bon e, alth ough im m obilization an d non –weight-bearing on the injured extrem ity m ay be indicated. For high-risk stress fractures such as th ose on the


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ten sion side of th e fem oral n eck, prophylactic fixation m ay preven t furth er propagation or displacem en t.

MEDICAL CONDITIONS Cardiovascular Disease

Figure 9.16 The lateral radiograph of the left tibia of a collegiate

track athlete demonstrating cortical thickening and the dreaded black line of a stress fracture. (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown CM, eds. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Sudden death in an athlete, although rare, is a devastating event that is m ost com m on ly related to cardiac causes. Th e cardiovascular screen in g portion of th e preparticipation evaluation is crucial to preventing the potentially severe outcom es of cardiovascular dysfunction or disease. Hypertrophic cardiomyopathy is implicated in m ore than one quarter of sudden cardiac deaths in athletes (Fig. 9.17). Affecting 1 of 500 athletes, this condition is usually asymptom atic and m ay initially present as sudden death due to dyn am ic outflow obstruction or ven tricular arrhyth m ia. Hypertroph ic cardiom yopathy is inherited as an autosom al dom in ant trait, and fam ily history of sudden death , especially in a relative youn ger th an 45 years, sh ould raise con cern . Physical exam in ation fin din gs m ay in clude a late systolic m urm ur th at in creases in intensity on stan ding or with Valsalva m an euver an d decreases with squattin g. Th e affected athlete m ay report dyspn ea on exertion, chest pain , palpitation s, or syn copal episodes. If suspected, th e ath lete sh ould be proh ibited from play and referred to a cardiologist. Echocardiography is diagnostic. Marfan syndrome h as been iden tified as a risk factor for sudden death in th e ath lete due to acute dissection of the aortic root. A con stellation of physical exam ination findings in cluding tall stature, arachnodactyly, and lens dislocation s distin guish es th is con dition an d sh ould be recogn ized durin g th e preparticipation evaluation . Ath letes with Marfan syndrom e should undergo a thorough cardiovascular evaluation before bein g cleared to play. A n um ber of addition al cardiovascular con dition s with possibly serious con sequen ces m ay silen tly affect th e ath lete. Prolonged QT syndrome is a fam ilial con dition that involves an abnorm al repolarization of the cardiac conduction system and m ay lead to syncope or fatal arrhyth m ia. Typically asymptom atic, prolon ged Q T syn drom e m ay be diagn osed by a Q T in terval of m ore th an 480 m illisecon ds on electrocardiography. Congenital coronaryarteryabnormalities m ay be asymptom atic or present as exertional chest pain from kin kin g of an an om alous vessel. “Pistol’’ Pete Maravich , a well-known collegiate and professional basketball player, collapsed after a recreation al basketball gam e and died at an age of 40 years from a h eart attack caused by a congenitally m issin g left coronary artery. Valvular disease also m ay afflict ath letes without any symptom s. Abn orm al h eart m urm urs on physical exam in ation m erit further evaluation . Coronary artery disease is the m ost com m on cause of death in older ath letes. Risk factors sh ould be m in im ized to prevent complications, and athletes wh o report

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A

B Figure 9.17 (A) Hypertrophic cardiomyopathy diagram. (B) Postmortem heart specimen from

patient with hypertrophic cardiomyopathy. (A: Reprinted with permission from Springhouse, ed. Just the Facts: Pathophysiology. Philadelphia, PA: Lippincott Williams & Wilkins, 2004. B: Reprinted with permission from Lilly LS, ed. Pathophysiology of Heart Disease. 2nd ed. Baltimore: Williams & Wilkins, 1998.)

exercise-in duced ch est pain or palpitation s sh ould un dergo stress testin g. The Am erican Heart Association recom m en ds exercise testin g in m en older th an 40 years an d wom en older th an 50 years wh o h ave at least on e cardiac risk factor. All ath letes older th an 65 years sh ould h ave exercise testing to screen for potentially serious coronary artery disease.

Asthma/Exercise-Induced Bronchospasm Asthma, a con dition m arked by airway hypersen sitivity with a ran ge of severity, com m on ly affects ath letes an d deserves special consideration due to respiratory stress of ath letics. Ch aracterized by in term itten t airway in flam m ation resultin g in bron ch ocon striction an d in creased m ucus production , asth m a causes poten tially severe sym ptom s of wh eezin g, sh ortn ess of breath , ch est tigh tn ess, an d cough in g. Asthm a attacks, if untreated, m ay result in severe chest pain, hypoxia, an d loss of con sciousn ess. Triggers in clude aller-

gen s, exercise, physical or em otion al stress, or viral illn ess. After addressin g an d eradicatin g en viron m en tal causes, m edical m anagem ent focuses on reversal of bron chospasm and reduction of inflam m ation. Inhaled β -agonists such as albuterol are a m ainstay of treatm en t of acute asthm a attack and act on β -adrenergic receptors in th e sm ooth m uscle of th e airways to prom ote bron ch odilation . An tich olin ergics such as ipratropium also reduce bron chospasm . Preventive agen ts generally suppress chron ic inflam m ation and hypersen sitivity an d in clude glucocorticoids, leukotrien e blockers, an d an tih istam in es. Ath letes with n orm al lun gs m ay experience asthm a-like sym ptom s durin g or after periods of exercise. Affecting up to 50% of cold weath er ath letes, exercise-induced bronchospasm presen ts screen in g ch allen ges as ath letes m ay h ave n o m edical h istory or fam ily h istory of asth m a an d m ay be asymptom atic at rest. Challenge testing in which a 10% to 15% decrease in peak expiratory flow rate or 1-second forced expiratory volum e after 6 to 8 m inutes of strenuous


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exercise con firm s th e diagn osis. A greater th an 50% decrease indicates severe disease. Athletes m ay also develop a cough with ch allen ge testin g, wh ich is also in dicative of exercise-in duced bron ch ospasm . Treatm en t gen erally in volves m odification of exercise routine to m inim ize triggers an d prophylactic bronchodilator therapy. Asthm a does not preclude athletic participation, and preven tion of symptom s sh ould be th e goal of m an agem en t. The athlete should be educated about early warning signs of attack, and appropriate ph arm acological treatm en t sh ould be readily available. A severe attack m ay warrant supplem ental oxygenation and transfer to a h ospital.

ion . Broad-spectrum an tibiotics sh ould be in itiated after obtain in g a cerebral spin al fluid specim en for an alysis due to risk of bacterial etiology. Viral m en in gitis is typically a self-lim ited con dition th at needs only supportive care, but bacterial m en in gitis is associated with severe complication s in cludin g death an d requires em ergen t m edical in terven tion . Th e m ost com m on organ ism s in th e ath letic population are Streptococcus pneumoniae and Neisseria meningitidis, an d on ce speciated, an appropriate an tibiotic regim en sh ould be tailored specific to the organism . N. meningitides is of particular con cern in th e ath letic population due to an in creased prevalen ce foun d am on g college studen ts livin g in close quarters.

Infectious Disease

Mononucleosis In fectious m on on ucleosis is caused by th e Epstein –Barr virus or cytom egalovirus and eventually affects 90% of adults at som e poin t in their lives. Spread by oral secretions, sh aring water bottles, or close contact, m ononucleosis is ch aracterized by a triad of fever, pharyngitis, and lym ph aden opathy. Splen om egaly is also associated with th is con dition , an d th us con tact sports sh ould be avoided during acute infection to prevent splenic injury. Symptom atic treatm ent an d prevention of possible complications com prise stan dard treatm en t, an d sym ptom s usually resolve in 4 to 8 m on th s.

Th e n ature of th e sports lifestyle puts ath letes at risk of acquiring and transm itting in fection. Th e stress on the im m un e system of the training ath lete com bined with close quarters in locker room s an d on team buses an d th e sh aring of equipm ent, towels, and water bottles create an en vironm en t conducive to spread of in fection. Wh ile m ost infectious agents cause m ild, self-lim ited disease, athletes m ay be exposed to poten tially deadly organism s. The key to m an agem en t of in fectious diseases am on g ath letes is preven tion . San itary practices such as h an d-wash in g an d usin g clean towels m ust be em ph asized an d players sh owing signs or symptom s of infection should be evaluated and treated. Un iversal body fluid precautions should be m aintain ed wh en treatin g all ath letes, an d all equipm en t sh ould be clean ed th orough ly with an an tim icrobial solution after use.

Staphylococcus Infection Staphylococcus aureus, an organ ism that com m only colonizes the n ares and skin of athletes, m ay cause serious in fection if the body’s natural defenses are breach ed. Even sm all cuts in th e skin provide a portal for a virulent strain of th is organ ism to establish an in fection th at m ay ran ge from m ild local cellulitis or inflam ed boil to poten tially fatal system ic bacterem ia. Recen tly, outbreaks am on g ath letes of com m unity-acquired m eth icillin-resistant Staphylococcus aureus, an organ ism th at previously existed on ly in health care facilities, have instigated n ational concern due to th e virulen ce an d ten acity of th is in fection . To preven t spread, athletes should practice good hygiene, avoid sh arin g of towels and equipm en t, and cover skin lesions. Antibiotics m ay be required to eradicate the organism . Meningitis Men ingitis is m ost com m only caused by en teroviruses and is characterized by fever, headach e, n eck stiffness, and signs of m en in geal irritation such as pain with passive n eck flex-

ENVIRONMENTAL ILLNESS Heat Illness Th e in ten sity in h eren t to ath letics puts players at risk of h eat illn ess even during m oderate playin g con dition s since durin g m axim al exercise, th e m uscles can produce 15 to 20 tim es m ore en ergy th an at rest. Th is en ergy is con verted to heat and is a m ajor contributor to the developm ent of h eat illn ess. Involvin g a spectrum of con dition s from m in or dehydration to h eatstroke, h eat illn ess results wh en th e h eat-dissipatin g m ech an ism s of th e body are overwh elm ed. Th e hypoth alam us is th e regulator of core temperature in the body and is responsible for orchestratin g heat loss. Heat exchan ge requires a temperature gradient an d occurs by conduction via direct contact between objects, convection by transfer to circulatin g air, radiation via direct release into atm osphere, an d evaporation of perspiration. Th e body’s m ost poten t h eat dispersion m ech an ism , perspiration, m ay transfer up to 1,000 kcal of heat per hour into the atm osphere as the exercising athlete produces 1 to 2 liters of sweat per hour. Other heat-dissipatin g m echanism s include peripheral vasodilation, increased cardiac output an d m in ute ven tilation , an d elevation of core body tem perature. If th e th erm oregulatory m ech an ism s of th e body are overcom e by in adequate hydration , poor

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conditioning an d acclim atization , extrem e heat, or inappropriate cloth in g, th e th erm oregulatory capacity of th e body will fail an d h eat illn ess will en sue.

be n ecessary, an d vital sign s an d body tem perature sh ould be closely m on itored to preven t overcorrection .

Prevention of Heat Illness Minor Heat Illness An um ber of m inor heat-related conditions constitute early warning signs that an athlete is overh eating. Miliaria rubra, or h eat rash , is a pruritic papular rash th at m ay erupt with overexposure to h igh h eat an d h um idity, especially with clothing that impedes evaporation of sweat. Caused by occluded sweat glan ds, h eat rash is treated with coolin g an d dryin g of th e skin an d m ay take 7 to 10 days to resolve. Heat cramps strike large m uscle groups, such as th e gastrocn em ius, quadriceps, or h am strin gs, an d are caused by sodium deficiency from inadequate hydration and electrolyte in take coupled with profuse sweatin g. Ath letes wh o lose excessive sodium in th eir sweat are at greater risk for heat cramps and m ay ben efit from additional salt in th eir diet an d fluids. Treatm en t in volves rehydration with electrolyte or salt solution as well as coolin g th e ath lete an d stretchin g th e cramping m uscle group. Heat illness m ay also m an ifest as heat syncope from orthostasis caused by periph eral vasodilation , ven ous poolin g, an d dehydration . Men tal status quickly improves on ce th e ath lete is supin e, an d m an agem en t of h eat syn cope in volves m ovin g th e ath lete in to a sh aded area, elevatin g th e legs, an d rehydration .

Heatstroke As the therm oregulatory system of th e body fails and the core temperature rises, m ore serious heat-related illnesses m ay occur. Heat exhaustion presen ts with fatigue, m alaise, nausea, and h eadache in an athlete with norm al m en tation an d n o n eurological sym ptom s. Th e ath lete m ay appear flush ed, with profuse sweatin g an d cold clam m y skin , an d core body temperature m ay approach 104 ◦ F (40 ◦ C). Th e ath lete with symptom s of h eat exh austion sh ould be rem oved from play im m ediately an d rapidly cooled to preven t progression to h eatstroke. Heatstroke represen ts an em ergen cy as th e th erm oregulatory system h as been overwh elm ed beyon d th e poin t of spon tan eous recovery. Th e ath lete sufferin g from h eatstroke experien ces h eat exh austion sym ptom s coupled with severe m ental status im pairm en t an d core body tem perature of m ore th an 104 ◦ F (40 ◦ C). With m ortality rates in excess of 10%, h eatstroke warrants im m ediate activation of em ergen cy protocol while rem ovin g cloth in g an d m ovin g th e ath lete to a cool or sh aded location. A direct correlation has been dem on strated between the duration of elevated core tem perature an d outcom e with in creased m orbidity an d m ortality associated with hyperth erm ia lasting m ore than 60 m in utes. Aggressive cooling should be initiated im m ediately with ice im m ersion , coolin g blan kets, fan s, or in tern al coolin g m easures an d sh ould con tin ue un til core body temperature is less th an 101.8 ◦ F (38.8 ◦ C). In travenous hydration m ay

Th e key to m an agem en t of h eat illn ess is preven tion . En couraging copious hydration and recogn ition of the signs an d symptom s of heat illn ess should be emphasized during extrem ely hot playing con ditions. Athletes should h ave access to plen ty of water and relief from the environm ent, an d equipm ent and clothing should be ligh tweigh t and allow free evaporation of sweat. Th ose with a history of heat illness require evaluation prior to participation and should return to play in a graduated m an n er un der supervision of the trainer. Any event in which h eat illness is a risk should h ave ice im m ersion im m ediately available.

Hydration Adequate hydration is critical to protecting athletes from un toward effects of h eat, an d optim al hydration en tails m atching fluid and electrolyte loss (Table 9.8). Hydration status m ay be assessed by weight m onitoring before, during, and after exertion. Mild dehydration is represented by 2% to 3% body weigh t loss an d sign als n eed for hydration. Athletes with m ore than 5% weight loss are severely dehydrated an d sh ould be proh ibited from playin g. Sports drin ks h ave evolved to address electrolyte depletion from exertion an d sh ould be used in con jun ction with free water. Ath letes who consum e too m uch free water without adequate sodium in take m ay be at risk for developin g exertional hyponatremia.

Acclimatization Acclimatization is n ecessary prior to full participation in extrem e playing condition s such as the sum m er preseason for m ost fall sports. Achieving an adequate level of fitness first is important before initiating acclim atization as getting fit in extrem e environm ents is coun terproductive. Involving a gradual increase in environm ental exposure tim e and

TABLE 9.8

FLUID REPLACEMENT GUIDELINES National Collegiate Athletic Association Sports Medicine Handbook ■ 8–16 oz water 1 h prior to exertion ■ Continue drinking every 15–20 min during activity ■ After exercise, replace fluid lost (1 qt per 2 lb) National Athletic Trainers Association ■ 16 to 20 oz of fluid 2–3 h before exertion ■ Immediately prior to exercise, consume 6–10 oz ■ Take 6–10 oz every 15–20 min during exercise ■ After exercise, consume fluid in excess of what was lost (Adapted from Howe AS, Boden BP. Heat-related illness in athletes. Am J Sports Med. 2007;35(8):1384–1395.)


the degree and duration of exertion, proper acclim atization generally takes 10 to 14 days. During this tim e, physiological ch anges including enhanced cardiac output, heat exch an ge m ech an ism s, an d ren al fun ction im prove th e ath lete’s ability to withstand hot playing conditions. Hydration requirem en ts in crease with acclim atization .

Cold Illness Ath letes participating in sports at cold temperatures are at risk for developing illness or injury from exposure. Norm ally, tem perature h om eostasis is m ain tain ed by hypoth alam us-m ediated m ech an ism s to con serve an d produce h eat such as periph eral vasocon striction an d sh iverin g. Sim ilar to h eat illn ess, m an agem en t of cold illn ess sh ould focus on preven tion. Weather forecasts should be m on itored, and athletes sh ould be alerted in th e event of cold or in clem ent weather so that they m ay dress appropriately. Insulation is improved by layerin g of cloth ing. Hydration should be encouraged regardless of th e level of thirst. Sh elter an d rewarm in g equipm en t sh ould be available on site, an d any athlete who shows early sign s or sym ptom s of cold illness should be evaluated.

Hypothermia Hypothermia occurs wh en th ese m ech an ism s are overcom e by extrem e cold an d is defined as the cooling of core body temperature to less th an 95 ◦ F (35 ◦ C). Ath letes exposed to the elem ents without proper clothing, equipm en t, trainin g, or sh elter are at risk for developin g hypoth erm ia an d m ay presen t with un con trollable sh iverin g, tachycardia, dysarth ria, an d altered m en tal status. Ath letes with severe hypoth erm ia, in wh ich th e core body tem perature drops to less th an 88 ◦ F (31 ◦ C), exh ibit global physiological impairm en t that include hypotension, bradycardia, apnea, and reduced level of consciousn ess. Th e sh iverin g respon se an d level of alertness wane with increasing severity. Treatm en t of hypoth erm ia varies with severity. Mild hypoth erm ia m ay be m an aged with rem oval from cold en viron m en t, in sulation , an d rewarm ing with blan kets, h eaters, an d warm fluids. Severe hypotherm ia warrants activation of the em ergen cy respon se plan an d requires aggressive yet cautious rewarm in g with extern al an d in tern al m eth ods. Th ese patien ts sh ould be m on itored in an in ten sive care settin g an d rewarm in g sh ould not exceed 2 ◦ C per hour to preven t ventricular arrhyth m ia an d hypovolem ic sh ock.

Frostbite Ath letes exposed to freezing temperatures are at risk for frostbite. Characterized by ice crystal form ation in the extracellular spaces, frostbite generally affects bare skin and distal extrem ities as exposure com bin ed with periph eral vasoconstriction and dehydration leave theses regions vulnerable to freezing. Th e lower extrem ities, in particular th e great toe, are m ost com m on ly affected. In creasin g pain an d

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a gradual loss of both sen sation an d pliability in dicate th e developm en t of a cold in jury, an d th e affected area sh ould be protected from th e cold an d gen tly rewarm ed to preven t th e irreversible dam age of frostbite. Frostbitten tissue is h ard, m ottled, an d in sen sate an d m ay be superficial or in volve th e deep tissues in cludin g m uscle, n eurovascular structures, and bone. Often occurring in hypotherm ic patien ts, frostbite treatm en t sh ould in itially address core body temperature. Th e area of frostbite sh ould be rewarm ed in a water bath at 40 ◦ C to 42 ◦ C. Rubbin g th e tissue sh ould be avoided to preven t furth er dam age, an d rewarm in g sh ould n ot be in itiated if th ere is any ch an ce of refreezin g. Dem arcation of affected tissue m ay take several weeks, an d debridem en t an d am putation sh ould be delayed for 90 days.

Altitude Illness Th e reduced barom etric pressure an d low oxygen of h igh altitude introduce unique environm ental factors to the athlete. Hypobaric hypoxia m ay result in h igh -altitude syn drom es such as acute m ountain sickness, high-altitude cerebral edem a, or h igh -altitude pulm on ary edem a. Headache is generally the first symptom of altitude sickness. A h eadach e alon g with on e or m ore addition al symptom s to include nausea, dizzin ess, fatigue, or sleep disturbance represen ts acute mountain sickness, a condition that usually occurs with in 12 h ours of arrival to an altitude. Cessation of ascen t an d adaptation to th e curren t altitude m ay alleviate symptom s, and prophylactic acetazolam ide or dexam ethasone m ay prevent developm ent of altitude sickness. Neurological or pulm on ary symptom s m ay sign ify on set of poten tially fatal cerebral or pulm on ary edem a an d n ecessitate supplem ental oxygenation and im m ediate descent.

THE FEMALE ATHLETE Wom en represen t a rapidly growin g segm en t of the ath letic population. The inaugural m odern sum m er Olympic Gam es in Ath en s in 1896 featured n o fem ale ath letes. Wom en represen ted 42% of th e m ore th an 10,500 athletes wh o competed in th e 2008 sum m er Olympics in Beijin g, and in the 2012 Olympics in London, the num ber of fem ale athletes is expected to equal the num ber of m ale athletes. Th e fem ale athlete has also experien ced a substantial improvem ent in perform an ce. The winner of th e wom en ’s 2008 Boston Marath on would h ave defeated th e 1968 win n er by m ore th an 1 h our. With th is rise in participation an d perform an ce, a n um ber of con dition s an d in juries specific to th is population h ave becom e apparen t. Most of th e differen ces between gen ders th at in fluen ce ath letic participation are clearly evident. Wom en are sm aller, less m uscular, an d reach m aturity at an age younger than th eir m ale coun terparts. Osteoporosis, iron deficien cy an em ia, disordered eatin g, an d pregn an cy are con dition s to con sider in th e fem ale ath lete.

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Several m usculoskeletal m an ifestation s of th e differen ce between th e arch itecture of th e m ale an d fem ale body have been identified, including a greater incidence of stress fractures, ACL injuries, patellofem oral dysfun ction, shoulder in stability, foot problem s, an d scoliosis am on g fem ale ath letes.

The Female Athlete Triad Th e female athletic triad of disordered eatin g, am en orrh ea, an d osteoporosis is a con dition th at h as garn ered con siderable atten tion sin ce th e term was con ceived by th e Am erican College of Sports Medicin e Task Force on Wom en ’s Issues in 1993. Most com m only affecting wom en in enduran ce sports (run n in g, swim m in g), sports with weigh t categories (rowing), an d sports that emphasize lean body type (gym n astics, dan ce, ch eerleadin g), th e fem ale ath letic triad is a preven table con dition th at m ay lead to severe sh ort-term and chronic consequences. Th e train ing fem ale ath lete is pron e to a poten tially detrim en tal beh avioral pattern of disordered eatin g an d excessive exercise. Deliberately or un con sciously m otivated by a desire to m ain tain weight or body type or by a fear of gaining weight, affected ath letes m ay restrict calories (an orexia n ervosa), bin ge an d purge (bulim ia n ervosa), or en gage in oth er pattern s of disordered eatin g. Disordered eatin g m ay be coupled with in appropriate use of m edication s or excessive exercise an d results in in adequate n utrition an d poor en ergy. Am en orrhea, or at least 3 m onths of m issed m en strual periods, m ay also be a con sequen ce of th is path ological beh avior. Caused by reduced estrogen production from poor n utrition , lack of en ergy, an d low body fat, am en orrh ea con stitutes an importan t sign th at n orm al physiologic processes are impaired. Th e hypoestrogen em ic an d poor n utrition al state signified by am enorrhea is associated with in creased cardiovascular risk, poor im m unological function, and loss of n orm al bon e den sity. Th e resultan t osteopen ia from deficien t estrogen an d calcium leaves th e bon es brittle an d susceptible to fracture, an d severe postm enopausal osteoporosis m ay develop. Ahigh level of suspicion m ust be m aintained when evaluatin g th e fem ale ath lete. Warn in g sign s in cludin g weigh t loss, alopecia, hypertrich osis, dry skin , oral caries, stress fracture, and depression should alert th e physician that a serious condition m ay be developing. Prevention th rough m ultidisciplin ary education is clearly th e best approach for the fem ale athlete triad, and any athlete who exhibits warnin g sign s sh ould promptly be referred to an appropriate health care professional who should collaborate with dieticians, psychiatrists, and psychologists. Coaches and fam ily m em bers sh ould also be in volved in th e treatm en t. Ph arm acological th erapy m ay be in dicated in severe cases in cluding oral contraceptive pills to regulate horm one levels, vitam in D supplem en tation to aid in calcium absorption , bisph osph on ates an d calciton in to slow bon e resorption , an d an tidepressan ts to am eliorate depressive symptom s.

To prevent complications, athletes exhibiting sign s of th e fem ale triad who are less than 85% of ideal body weight sh ould not be allowed to participate in regular physical activity.

REHABILITATION Th e goal of reh abilitation is to restore th e lost ran ge of m otion, strength , and function that resulted from an injury, allowin g th e ath lete to return to th eir previous level of perform an ce. Takin g in to accoun t th e n ature an d severity of athletes’injury, th e physician in collaboration with a trainer or physical therapist is responsible for establish ing an appropriate reh abilitation program that allows ath letes to safely an d quickly recover so th at th ey m ay return to play. An un derstan din g of th e physiology of th e in jury is required for appropriate reh abilitation , an d proper precautions should be m aintained to m in im ize pain and preven t rein jury. Reh abilitation is divided in to an acute ph ase focused on con trolling the inflam m atory response, a subacute phase em ph asizin g ran ge of m otion an d recon dition in g, an d a chronic phase of strength ening and gradual return to sports-specific activity. The initial objective of rehabilitation is the reduction of pain, swelling, an d inflam m ation through the use of PRICE along with anti-inflam m atory m edications. Im m obilization, while essential for proper h ealin g, quickly results in loss of ran ge of m otion and m uscle m ass and early ran ge of m otion is important to lim it stiffn ess and weakness. Several strategies m ay be im plem en ted to restore m obility in cludin g active an d passive ran ge of m otion , stretch in g, an d join t m obilization an d m an ipulation (Fig. 9.18). With th e advan cem en t of range of

Figure 9.18 Range-of-motion exercises help to restore joint mobility. (Reprinted with permission from Fu FH, Stone DA, eds. Sports Injuries: Mechanisms, Prevention, Treatment. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2001.)


m otion, a gradual m uscular stren gthenin g plan m ay be in itiated through a com bination of open and closed kinetic ch ain fun ctional exercise techniques. Durin g open chain exercises, in wh ich th e distal extrem ity is n ot fixed, con traction of the agonist m uscle produces m ovem ent. Conversely, closed chain exercises, in which the distal extrem ity is fixed, rely on reciprocal co-contraction of agonist and antagon ist m uscles an d m ore closely reproduces n atural fun ctional dem ands. Enduran ce training should be perform ed as an adjunct to strength exercises to lim it fatigue, and proprioception an d n eurom uscular train in g prom ote dyn am ic stability and prevent rein jury. With the in crease in stren gth an d endurance, the focus of reh abilitation sh ifts to sportsspecific exercise to prepare the athlete for return to play. Athletes, especially h igh-perform ance athletes, m ay push th e extrem es of reh abilitation . Aggressive th erapy m ay be coun terproductive to recovery, an d rein jury m ay occur. Th e team physician sh ould be in com m un ication with th e athletic trainer an d the physical therapists about reason able rehabilitation goals and return to play.

PHARMACOLOGY OF SPORTS Anti-Inflammatories and Analgesics Medications have an important role in the m an agem ent of sports injuries. Often used as an adjunct to rest or therapy, ph arm acological treatm en t of sports in juries focuses on suppressing th e inflam m atory respon se an d reducin g th e pain associated with th e in jury. In th e acute respon se to tissue injury, h igh levels of in flam m atory m ediators such as prostaglan din s, th rom boxan es, an d leukotrien es accum ulate in the area of injury. Th ese substances prom ote vasodilation, in creased vascular perm eability, and recruitm ent of leukocytes to breakdown an d rem ove n ecrotic tissue an d debris. Th is tissue process m an ifests clin ically as swellin g, local heat, and pain. Chronic inflam m ation is characterized by persistent symptom s of acute in flam m ation. NSAIDs such as ibuprofen and n aproxen have an tiinflam m atory effects and analgesic and an tipyretic properties. Th is class of drugs is used un iversally for ath letic injuries and functions prim arily by in hibition of the cyclooxygenase enzym e complex. Composed of two isoen zym es, COX-1 an d COX-2, cyclooxygen ase con verts arach idon ic acid to prostaglan din s. COX-1 is in volved in n orm al prostaglan din syn th esis in th e gastric m ucosa, ren al tissue, platelets, an d en doth elial cells, an d in h ibition of th is isoen zym e is respon sible for th e m ajority of side effects from NSAIDs. Th e th erapeutic effect of NSAIDs is exerted upon the COX-2 isoenzym e. In th e acute response to injury, local COX-2 expression increases up to 80-fold, producing high levels of prostaglandins, which in turn lead to inflam m ation and pain. Selective COX-2 inhibitors such as celecoxib are effective at suppressing inflam m ation with fewer side effects. Ultim ately, th e goal of NSAID th erapy is reduction

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of in jury-associated pain an d in flam m ation so th at reh abilitation m ay occur. Un toward effects in cludin g dyspepsia, gastric ulceration , an d ren al failure sh ould be con sidered wh en usin g NSAIDs. Corticosteroids possess potent anti-in flam m atory properties an d fun ction by in h ibition of th e vasoactive respon se to in jury, suppression of leukocyte recruitm en t, an d reduction of cytokin e expression . Awide spectrum of activity an d side effects exists am on g different corticosteroids, and the prim ary m ean s of delivery in ath letes is oral adm in istration an d local in jection . Oral corticosteroids h ave excellen t an tiin flam m atory properties, but system ic side effects such as glucose intolerance, hyperten sion, osteoporosis, and im paired woun d h ealin g preclude routin e use. Local in jection s are associated with fewer system ic com plication s an d m ay be used to decrease local in flam m ation in bursitis, ten din itis, an d arth ritis. Corticosteroids sh ould n ot be in jected in to ten don s or ligam en ts due to in creased risk of rupture. Acetam in oph en is an effective an algesic with lim ited an ti-in flam m atory properties. Possessin g a m ore ben ign side effect profile th an NSAIDs, acetam inophen m ay be used as a sin gle agen t for m ild to m oderate in flam m ation or as an adjun ct to NSAID th erapy. Hepatotoxicity con stitutes th e m ajor dan ger of acetam in oph en th erapy an d m ay be preven ted by lim itin g acetam in oph en in take to less th an 4 g per day in adults. Narcotics such as hydrocodone and oxycodone bind opiate receptors to in h ibit con duction with in cen tral pain path ways. Powerful an algesics, n arcotics, sh ould be reserved for pain from severe injury or postoperative pain. Toleran ce develops over 1 to 3 weeks from upregulation of opiate receptor expression , an d physical depen den ce m ay result from prolon ged use. Because of risk of addiction , n arcotics sh ould be used sparin gly.

Commonly Used Supplements, Vitamins, and Drugs Ath letes use a variety of dietary an d ph arm acological substan ces to en h ance perform an ce, control weight, improve n utrition , and recover from in jury. Most substan ces used by athletes are dietary supplem ents that are available over th e coun ter an d gen erally pose m in im al risk to th e ath lete wh en taken as directed. Creatine is am on g th e m ost com m on supplem en ts used by high school and college athletes and enh ances shortterm train in g stam in a th rough augm en tation of aden osin e triphosphate regeneration. A 2001 survey of high school athletes foun d that 44% of high school senior athletes used creatin e. Triggerin g a sh ift of fluid in to th e cells, creatine causes a th eoretical risk of dehydration, and reports of cram ps, m uscle in jury, an d ren al dysfun ction h ave been associated with use. Stim ulan ts such as pseudoephedrine an d caffeine m ay be used by ath letes to in crease en ergy an d en duran ce. Wh ile caffein e is gen erally perceived to be ben ign , ath letes sh ould

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be aware of in creased sh ort-term risk of h eart attack, arrhythm ias, and sudden cardiac death with heavy use. Recogn izin g th e ubiquity of use am on g th e gen eral public, caffeine is legal in m ost sports although the International O lym pic Com m ittee (IO C) h as in stituted a daily th resh old of 9 m g/ kg (approxim ately 5 cups of coffee). Ephedrine is a sympath om im etic initially developed as a weight loss aid. Abused by athletes wh o sought to take advan tage of its “energizin g’’qualities, eph edrin e h as been ban n ed by th e IO C due to in creased risks of cardiac dysfun ction . Eph edrin e is frequently com bined with caffeine an d aspirin (“ECA stack’’) and has been linked to num erous deaths am on g ath letes. Athletes who abuse anabolic steroids aim to augm en t th e poten t effects of en dogen ous an drogen ic h orm on es on m uscle m ass, strength, and recovery from injury. While testosterone an d syn th etic an alogues h ave been sh own to improve stren gth and perform ance when taken in supraphysiologic doses, th ey possess a substan tial side effect profile. In creased rates of h eart disease, in creased aggression , hypercoagulability, testicular atrophy, gyn ecom astia, an d hirsutism am on g ath letes wh o abuse anabolic androgen ic steroids reflect th e dangers of use. Dehydroepiandrosterone and androstenedione are precursors in th e gon adal steroid path way an d are con verted by th e body in to testosteron e. Wh ile th e ergogen ic ben efits of th ese testosteron e precursors h ave yet to be clearly dem onstrated, the adverse effects of elevated testosteron e h as led to th e ban n in g of th ese substances by the IOC and m any oth er sports organization s. Human growth hormone ( HGH) is also an endogenous occurrin g substan ce abused for its ergogen ic effect. Developed to treat patien ts with en dogen ous growth h orm on e deficien cy, HGH exerts an an abolic effect on m uscle growth and increases fat m etabolism . Abuse is associated with hyperten sion an d acrom egaly am on g oth er detrim en tal physiologic effects. Ath letes m ay boost aerobic capacity by blood dopin g. Hom ologous or autologous transfusion prior to a sporting even t confers the advantage of increased circulating red blood cells for en h an ced oxygen delivery. Ath letes m ay also use synthetic erythropoietin ( EPO) to improve aerobic capacity. Naturally produced by th e kidn eys to stim ulate red blood cell form ation , EPO abuse m ay result in con sequen ces of hyperviscosity from polycythem ia in cludin g heart attack, stroke, and pulm onary em bolus.

NUTRITION Athletes in training an d competition have complex nutrition al requirem en ts to build an d m ain tain m uscle, m axim ize oxygen ation delivery, optim ize m etabolism , an d recover from injury. Insufficient caloric intake m ay result in loss of m uscle m ass, loss of bon e den sity, m en strual dysfunction, and increased risk of fatigue, injury, or illness. A balan ced diet th at m eets caloric n eeds with proper pro-

portion s of carbohydrates, fats, protein s, an d vitam in s is essen tial to m ain tain in g physical well-bein g. Curren t recom m en dation s outlin e a diet con sistin g of approxim ately 55% to 60% of calories from carbohydrates, 10% to 15% from protein, and 25% to 30% from fats. Blood glucose an d glycogen stores provide th e substrate for energy production and are m aintained by dietary carbohydrates foun d in sugars. Daily in take recom m en dation s ran ge from 6 to 10 g of carbohydrate per kilogram of body weigh t per day. Dietary carbohydrate th at is n ot con verted to en ergy or glycogen m ay contribute to adipose stores. Dietary protein s from m eats an d n uts supply am in o acids for buildin g an d repair of m uscle tissue. Daily in take recom m endations for athletes range from 1.2 to 1.4 g per kilogram per day, alth ough ath letes wh o participate in sports th at em ph asize m uscle bulk an d stren gth m ay con sum e 1.6 to 1.7 g of protein per kilogram per day. Fat provides an energy substrate an d fat-soluble vitam ins and essential fatty acids. Ubiquitous in th e Am erican diet, excess in take builds adipose stores an d elevates blood ch olesterol levels. Polyun saturated an d m onounsaturated fatty acids found in fish, n uts, and vegetable oils sh ould compose the m ajority of fat in take, and saturated an d trans-fatty acids as well as ch olesterol should be avoided because of detrim ental effects on th e blood lipid profile. Ath letes m ust regulate their diets to ensure th at they con sum e th e appropriate am oun t an d proportion s of calories to optim ize perform an ce. Th e composition of th e diet sh ould be tailored to th e individual sport as endurance athletes m ay benefit from increased carbohydrate intake to m axim ize energy storage and production wh ile stren gth athletes m ay supplem ent their protein in take to prom ote m uscle growth. Carbohydrate loadin g by m axim izing intake wh ile taperin g train in g in ten sity in th e days leadin g up to a competition m ay boost glycogen stores and increase en duran ce. Before exercise, a carbohydrate-rich sn ack or sports drin k elevates blood glucose levels and provides energy. Fat sh ould be avoided before exercise as h igh -fat foods delay gastric em ptyin g an d m ay cause abdom in al discom fort. Durin g and after exercise, the dietary objective is to adequately replace utilized calories. A well-balanced m eal sh ortly after exercise serves to replace glycogen to restore en ergy an d provide am in o acids to repair m uscle tissue. Although disordered eating is m ore com m on in fem ale athletes, all ath letes are susceptible to m aladaptive eating and training behavior. Certain sports such as gym nastics, wrestlin g, an d crew are associated with h igh er risks of low body weigh t. Early recogn ition of disordered eatin g pattern s is vital to preven tin g serious complication s, an d ath letes who seek a certain weight or body type sh ould be referred to a dietician wh o can assist in con structin g a h ealthy diet th at will safely allow ach ievem en t of th ese objectives. Basic weigh t loss guidelin es in clude eatin g sm aller and m ore frequent m eals, lim itin g empty calories, and eating foods that prom ote satiety. Weight loss of 1 to 2 lb per week represen ts a h ealthy an d reason able goal. Basic


weigh t gain guidelin es con sist of con sum in g an addition al 500 to 1,000 cal per day an d ch oosin g h igh er calorie item s. A reasonable and healthy goal is 1 lb of weight gain every 2 weeks.

CONCLUSION Regardless of sport, level of participation , an d degree of perform an ce, ath letes con tin uously ch allen ges th e kn owledge an d skills of sports physician s. Th e diversity with in the ath letic population requires sports physicians to play a num ber of roles. They m ust play the role of pediatrician to recogn ize con dition s specific to ch ildh ood an d adolescen ce, th e role of internist to m an age m edical conditions, an d the role of orth opaedist to treat m usculoskeletal injuries. In addition , sports physician s m ust coordin ate th e m ultidisciplinary care for athletes. They m ust un derstand nutrition to encourage a balanced diet, iden tify m aladaptive eating behavior, and counsel athletes on the use of dietary supplem en tation . Sports physician s sh ould be fam iliar with the prin ciples of exercise an d rehabilitation from injury. Outside the realm of m edicine, sports physician s

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sh ould appreciate th e politics and eth ics of athletics and un derstan d th e rules an d requirem en ts specific to th e sport in wh ich ath letes participate. Th ey m ust en sure th at appropriate h ealth care policies an d em ergen cy plan s are establish ed. Successful sports physician s are able to in tegrate all of th ese prin ciples in to th eir practice wh ile dem on stratin g the availability, affability, and ability required for optim al care of athletes.

RECOMMENDED READINGS Botrè F, Pavan A. En h an cem en t drugs an d th e ath lete. Neurol Clin. 2008;26(1):149 –167. Guskiewicz KM, Bruce SL, Cantu RC, et al. National Athletic Trainers’Association Position Statem en t: Man agem en t of Sport-Related Concussion . J Athl Train. 2004;39(3):280 –297. Rice SG. Am erican Academy of Pediatrics Coun cil on Sports Medicin e an d Fitness: Medical Conditions Affectin g Sports Participation. Pediatrics. 2008;121(4):841 –848. Seto CK, Way D, O’Con n or N. En viron m en tal illn ess in ath letes. Clin Sports Med. 2005;24(3):695 –718. The Am erican Academ y of Fam ily Physicians, Am erican Academ y of Orth opedic Surgeon s, Am erican College of Sports Medicin e, Am erican Medical Society for Sports Medicin e, Am erican Orthopaedic Society for Sports Medicin e, Am erican Osteopath ic Society for Sports Medicin e. Con sen sus statem en ts. h ttp:/ / www.aafp.org/ online/ en/ hom e/ clinical/ publichealth/ sportsm ed.htm l.

Principles of Orthopaedic Traum a

10

Sam ir Meht a

INTRODUCTION Th e diagn osis, m an agem en t, an d un derstan din g of patien ts sustain ing traum atic orthopaedic injuries covers a wide array of m ech an ism s of in jury, fractures, soft tissue in juries, an d urgency. At its heart, orthopaedic traum a care is based on th e fun dam en tal prin ciples govern in g m usculoskeletal injury, and its m edical and surgical treatm ent. As with all surgical subspecialties, proper diagn osis of th e orth opaedic patien t requires a th orough h istory an d physical exam in ation. Radiograph ic an alysis using plain radiographs and, in certain situations, computed tom ography (CT) and m agnetic resonance im aging (MRI) are essential in providin g additional inform ation as it correlates to the clinical exam ination. Th is ch apter is dedicated to h igh ligh tin g prin ciples utilized to evaluate the orthopaedic traum a patient and detailin g a set of surgical em ergen cies th at all orth opaedic surgeons sh ould be fam iliar with and com fortable iden tifying and m an aging. A working knowledge of this list of diagn oses an d treatm en t regim en s is critical in avoidin g significant m orbidity and m ortality in the patient with orthopaedic injuries.

tion with th e ATLS protocol. Despite orth opaedic in terests bein g predom in an tly m usculoskeletal, th e orth opaedic surgeon sh ould assess the airway, check for breathing, and determ in e circulatory volum e an d h em odyn am ic stability. Typically, orth opedic in juries are diagn osed durin g th e secon dary survey on ce th e patien t is deem ed h em odyn am ically stable. However, patien ts with severe m usculoskeletal in juries th at comprom ise circulation can be diagn osed durin g th e prim ary survey. Th e proper evaluation of th e traum a patien t requires a th orough un derstan din g of th e m ech an ism of in jury as this allows for a high index of suspicion for specific injury pattern s as well as associated in juries. In th e un stable traum a patien t with an un kn own cause of hypoten sion , a h igh-en ergy blun t in jury m ech an ism (e.g., m otor vehicle or m otorcycle collision s an d falls from a h eigh t) m ay in crease the likelihood of a pelvic rin g injury, long bone fracture, or spin al cord in jury. Un explain ed hypoten sion in a patien t, especially with out a kn own th oracic or abdom in al in jury, sh ould prompt con sideration of a pelvic in jury or lon g bon e fracture as th e source of exsan guin ation or sign ifican t blood loss (Table 10.1).

Physical Examination

EVALUATION OF THE ORTHOPAEDIC TRAUMA PATIENT Nearly 60% of all traum a patien ts h ave an orth opaedic injury or m usculoskeletal complaint. It is imperative to adh ere to the Advan ced Traum a Life Support (ATLS) guidelines in evaluating any traum a patient. It is the obligation of an orth opaedic surgeon called to th e resuscitation bay to evaluate a patien t to begin h is/ h er exam in a-

As m en tion ed above, orth opaedic in jures are typically diagnosed during the secondary survey. Injuries associated with a gross deform ity of th e in volved extrem ity or large soft tissue defect with th e underlying bone or joint exposed m ay be obvious on exam ination and require prompt treatm ent during the secondary survey. More subtle soft tissue in juries (i.e., lacerations, abrasions, and ecchym osis) sh ould increase the suspicion for an underlying fracture or join t in jury (Fig. 10.1). Deform ity an d soft tissue in jury are

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TABLE 10.1

OCCULT BLOOD LOSS IN ACUTE FRACTURES Location of Fracture Ankle Elbow Femur Forearm Hip Humerus Knee Pelvis Tibia

Blood Loss (Units) 0.5–1.5 0.5–1.5 1.0–2.0 0.5–1.0 1.5–2.5 1.0–2.0 1.0–1.5 1.5–4.5 0.5–1.5

essen tial in diagn osin g orth opaedic in juries in th e un conscious patient. All patients who are awake sh ould be exam in ed in a system atic fash ion so as to m in im ize th e likelih ood of m issin g an in jury. Un con scious patien ts are thoroughly exam ined once awake (tertiary survey) for injuries n ot obvious at th e tim e of presen tation to th e resuscitation bay. The m usculoskeletal portion of the secondary survey starts with the proxim al upper extrem ity and is conducted

bilaterally wh ile observin g th e patien t’s facial expression durin g th e exam in ation , wh ich can provide addition al in form ation regardin g subtle in juries. The patien t’s shoulders, elbows, an d wrists are taken th rough ran ge of m otion . Th e upper arm an d forearm are palpated for ten dern ess. Th e h an d is assessed for soft tissue in jury, wh ich can be easily m issed on th e in itial exam in ation . Evaluation of “an atom ical sn uffbox’’ (space between th e exten sor pollicis brevis and exten sor pollicis lon gus tendons at th e level of th e dorsolateral wrist) ten dern ess aids in th e diagn osis of an un derlyin g scaph oid fracture. Th e vascular supply of each upper extrem ity is th en evaluated on th e basis of th e radial an d uln ar artery pulses, as well as th e degree of capillary refill. In the adequately resuscitated traum a patient, capillary refill sh ould be less th an two secon ds. Th e upper extrem ity exam in ation term in ates in a detailed n eurologic exam in ation with docum en tation of axillary, m usculocutaneous, radial, ulnar, and m edian nerve fun ction (Fig. 10.2). Th e radial nerve is assessed by testing for active wrist or thum b extension as well as sensation in the first dorsal webspace. Fractures about th e distal h um erus m ay result in in jury of th e radial n erve an d m ay m anifest as m otor weakness or sen sory loss. The ulnar n erve is evaluated with dem on stration of good h an d intrin sic m uscle activity by way of grip strength or spreadin g th e

A

B Figure 10.1 (A) A 37-year-old male patient with a blunt force trauma to the leg resulting in two small lacerations over the anteromedial tibia. A high index of suspicion should be maintained with this type of presentation. (B) Radiographs reveal a comminuted open tibia fracture.

Chapter 10: Principles of Orthopaedic Trauma

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Upper lateral brachial cutaneous n. Medial brachial cutaneous and intercostobrachial n.

Posterior brachial cutaneous and lower lateral brachial cutaneous n.

Medial brachial cutaneous and intercostobrachial n.

Posterior antebrachial cutaneous n. Medial antebrachial cutaneous n.

Medial antebrachial cutaneous n.

Lateral antebrachial cutaneous n.

Radial n. Ulnar n.

Figure 10.2 Sensory distribution of the

Ulnar n. Median n.

upper extremity.

fin gers to resistan ce as well as ligh t touch sen sation to th e sm all and ulnar half of the ring finger. Th e m edian n erve is tested by askin g th e patien t to give an “okay’’sign with th e thum b and index finger as well as by assessing sensation of th e palm ar aspect of th e th um b, in dex, lon g, an d radial half of the ring finger. Soft tissue in juries such as lacerations about th e wrist m ay cause a disruption of the ulnar or m edian n erves. In addition , fractures such as distal radius fractures m ay result in sign ifican t volar wrist swellin g an d patients m ay develop an acute carpal tun nel syndrom e requirin g im m ediate decompression of th e m edian n erve at the wrist. Atten tion is then turned to the thorax. Each clavicle, as well as th e stern um , is palpated for ten dern ess. Th e rib cage is gently squeezed toward the m idline to assess for tenderness secondary to rib fractures. The th oracic exam in ation exten ds distally to th e pelvic rin g. For th e h em odyn am ically stable patient that was not noted to have findings con sisten t with a pelvic fracture durin g th e prim ary survey, th e pelvis is exam in ed at th is poin t durin g th e exam in ation . Th e pelvis is exam ined by applyin g gentle pressure on the an terior superior iliac spin es in an an terior to posterior direction with the palm of both han ds. In addition, gentle m edial pressure is applied from the lateral aspect of each iliac wing with both h an ds. Th ese m an euvers are often un com fortable for patien ts with an un derlyin g fracture. Patien ts with m in im al

pelvic bleedin g associated with a pelvic fracture sh ould n ot h ave th is exam ination perform ed repeatedly by m ultiple exam in ers or with sign ifican t force in an effort to m in im ize th e risk of fracture displacem en t an d disruption of vessel tam pon ade. Patien ts with pelvic rin g in juries sh ould also un dergo a th orough gen itourin ary exam in ation to assess for open fractures within th e pelvic vault (e.g., open fracture through the vaginal wall) or neurologic injury. Exam in ation of th e lower extrem ities follows a sim ilar progression as seen with th e upper extrem ities. Each h ip, kn ee, and ankle is taken through a range of m otion. The thigh, lower leg, and foot are all palpated for tenderness. Particular focus should be given to the proxim al tibia to avoid m issing a subtle proxim al tibia (tibial plateau) fracture. Tibial plateau fractures th at are n ot obvious are n otorious for appearin g in n ocuous on plain radiograph s an d often require advan ced im agin g with a CT scan . Th e vascular exam in ation in cludes palpation of th e posterior tibial artery beh in d th e m edial m alleolus an d th e dorsalis pedis artery between th e first an d secon d m etatarsals on th e dorsum of the foot. Th e n eurologic exam in ation in cludes testin g th e term in al bran ches of the sciatic, tibial, an d peron eal n erves (Fig. 10.3). Th e peron eal n erve is furth er subdivided in to a superficial an d deep bran ch . Foot eversion stren gth an d sen sation over th e dorsum of the foot dem onstrates adequate

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L3 L1 L2 L3

L4 L5 S1 S2

Posterior cutaneous n.

S3 S4 S5 Femoral n. Lateral cutaneous n.

L4 Lateral cutaneous n. L3

Obturator n.

L5

Common peroneal n.

S2

S1

Femoral saphenous n.

Superficial peroneal n.

L4

L5

A

Superficial peroneal n.

Tibial n.

Sural n.

Common peroneal n.

Sural n.

S1

B

Figure 10.3 Sensory distribution of the lower extremity. (A) Dermatonal distribution and (B) peripheral nerve distribution.

m otor an d sen sory fun ction of th e superficial peron eal nerve. The deep peroneal nerve m otor function can be evaluated by testin g an kle dorsiflexion or great toe exten sion while sensation should be in tact to th e first dorsal webspace. In juries to th e proxim al fibula can result in injury to th e peron eal n erve prior to its division an d m ay m an ifest as loss of m otor function, sensory fun ction, or both. Th e typical presen tation is a patien t with a “foot drop’’ on the affected side—the foot is restin g in a plan tar flexed position an d th e patien t is unable to dorsiflex th e foot. Th e tibial n erve in n ervates th e superficial an d deep posterior compartm en ts of the lower leg as well as several m uscles in th e foot via its term in al bran ch es, th e m edial, an d lateral plan tar n erves. Motor fun ction of th e tibial n erve is tested by dem on stration of an kle plan tar flexion stren gth through the gastrocnem ius-soleus m uscle complex, while sen sation should be intact on the plantar aspect of the foot. Any injury to th e sciatic nerve proxim ally, either at the level of th e lum bar spin e or h ip, m ay result in m otor an d sen sory fun ctional loss of the lower extrem ity distal to the knee.

Spinal Cord Injury Every traum a patien t m ust h ave a detailed cervical, th oracic, an d lum bar spin e exam in ation docum en ted. In addition , patien ts suspected of h avin g a spin al cord in jury require a th orough n eurologic exam in ation docum en tin g m otor distribution and sensory derm atom al distribution of each cervical an d lum bar n erve root level. Th e upper an d lower extrem ity exam ination is sufficient for patients n ot suspected of h aving a spin al cord in jury. Th e clin ical outcom e of a patien t with a spin al cord in jury is based upon the initial fun ctional level (lowest functioning m otor and sensory n erve root). A detailed m otor and sensory exam ination of bilateral upper an d lower extrem ities n eeds to be con ducted to com pletely docum en t spin al cord fun ction . Th e exam in ation com m ences at the level of the shoulder. Sh oulder abduction den otes m otor strength in the C5 nerve distribution. Flexion at th e elbow tests C5 an d C6 wh ereas elbow exten sion tests th e C7 n erve root. Isolated C6 fun ction can be evaluated with wrist exten sion . Both C8 an d T1 m otor


functions are assessed by exam in ing the intrinsic hand m uscles. The associated derm atom al sensory pattern also sh ould be docum en ted. Sen sation over th e lateral sh oulder is in th e distribution of C5. Exam in ation of th e skin over th e th um b, m iddle fin ger, an d little fin ger con stitutes intact sensation to light touch in th e C6, C7, an d C8 distributions, respectively. The T1 derm atom al distribution is located along th e m edial aspect of the upper arm . Across the th orax and abdom en, there are no m otor function tests to be conducted. Certain anatom ic landm arks represent the derm atom al distribution of the th oracic spin al n erve roots. Th e T4 level is at th e n ipple. Th e T8 derm atom e can be tested at th e level of th e xiph oid process, whereas th e T10 level is at the um bilicus. Physical exam in ation of th e lower extrem ity begin s with m otor testin g of th e m ajor lum bosacral n erve roots. Hip flexion is associated with L2 an d L3 m otor function , wh ereas kn ee exten sion is associated with L3 an d L4 n erve root fun ction . Isolated L4 an d L5 n erve root fun ction can be tested with an kle an d great toe dorsiflexion , respectively. Ankle plantar flexion assesses isolated S1 nerve root m otor function. Derm atom al patterns for sensation to ligh t touch are as follows: (1) the m edial proxim al thigh is L2; (2) the m edial distal thigh is L3; (3) the m edial lower leg is L4; (4) the lateral lower leg is L5; and (5) the plantar aspect of the foot is S1. Th ere are a series of reflexes th at sh ould also be tested an d docum ented to complete the spin al cord evaluation. Th e biceps, brach ioradialis, an d triceps reflexes of th e upper extrem ity dem on strate an in tact spin al cord reflex at the level of C5, C6, and C7, respectively. Th e patellar and Achilles reflexes of the lower extrem ity dem onstrate an intact spin al cord reflex at th e level of L4 an d S1, respectively. Th e presen ce of a Hoffm an sign (in volun tary flexion of the thum b with pressure on the distal long finger) or a Babinski sign (upward curling of th e toes with posterior to an terior, lateral to m edial irritation of the plantar foot) signify upper m otor n euron signs. In the face of a suspected spinal cord injury, a rectal exam ination m ust also be docum en ted. The bulbocavernosus reflex is tested by pullin g of the Foley catheter with a finger in the rectum . The absence of th is reflex classifies th e patien t to be in a state of spin al sh ock and m ay last up to 48 hours followin g the injury. A repeat exam in ation at 48 h ours with a sim ilar fin din g signifies th at the state of th e spinal cord injury at that tim e is irreversible. Although acute pharm acologic treatm ent of spinal cord injuries rem ains controversial, the current treatm en t regim en involves adm inistration of intraven ous high-dose steroids within eigh t hours of injury.

Fractures Associated with Vascular Injury Extern al sources of h em orrh agic sh ock (e.g., fem oral artery laceration ) m ay also be addressed during th e prim ary survey as they are encountered after stabilization of th e airway

197

an d breath in g. Obvious vascular in juries with con tin ued bleedin g, regardless of wh eth er th ey are associated with an un derlyin g fracture, are in itially treated with pressure application over th e woun d. Prompt diagn osis an d stabilization of oth er life- an d lim b-th reaten in g in juries are param oun t wh ile sim ultan eously addressin g th e extern al bleedin g source. Th e patien t is typically taken to th e operatin g room with as m in im al delay as possible, an d th e appropriate con sult service(s) (i.e., vascular surgery) sh ould be n otified. An in jury to a m ajor vessel such as th e fem oral artery that is associated with an underlying fem ur fracture requires th e sim ultan eous con sultation an d in terven tion of orth opaedic surgery an d vascular surgery. A m ultidisciplin ary approach to th is patien t in th e operatin g room is critical to optim ize clin ical outcom es with sequen cin g of care bein g essen tial. O n e scen ario would in volve urgent orthopaedic stabilization of the long bone in jury with extern al fixation followed by defin itive vascular repair (Fig. 10.4). By repairin g th e bon e first, th e subsequen t vascular repair will not be jeopardized by the necessary m an ipulation of th e fracture. Alth ough blood loss from th e vessel in jury is tim e depen den t as is reperfusion of th e in jured lim b, repair of th e vascular in jury could be comprom ised wh ile stabilizin g th e un derlying fracture. Another potential option in th e m an agem en t of th is patien t would be tem porizin g vascular fixation with a com m ercially available sh un t with care taken to h ave excess sh un t m aterial present. O n ce th e lim b is reperfused an d bleedin g con trolled, th e orth opaedic procedure can follow.

Tertiary Survey All traum a patien ts adm itted to th e h ospital with an orth opaedic com pon en t to th eir in jury pattern sh ould receive a thorough tertiary physical exam ination once stable. Atertiary survey should also be conducted on all patients wh o were exam in ed in th e resuscitation bay. Patien ts wh o sustain m ajor in juries such as lon g bon e fractures or cervical spin e injuries are at risk for being distracted by their injuries and not recognizing pain elsewh ere from a m ore m inor injury (e.g., wrist/ sn uffbox ten dern ess from a scaph oid fracture or m etatarsal fractures of the feet). The tertiary exam in ation is specifically geared toward iden tifyin g m ore subtle m usculoskeletal injuries that require treatm ent either as an inpatient or at a later date as an outpatient.

OPEN FRACTURES An open fracture is defin ed as any fracture th at com m un icates with th e extern al en viron m en t via a soft tissue defect. Typically, open fractures are the result of high-energy traum a and m ay yield a spectrum of soft tissue in jury— from a “poke’’ hole to complete soft tissue devitalization, periosteal strippin g, an d exposed bon e. Wh en a patien t

198


B

A

C

D Figure 10.4 (A) Anteroposterior view of the left femur after a motor vehicle collision with a

comminuted femoral shaft fracture. The patient also had decreased pulses in the limb and an abnormal ankle-brachial index (less than 0.9). (B) The patient had a small open wound on the medial side of the thigh. (C) Exploration of the thigh revealed the deep profundus artery (arrow) at the level of Hunters canal intact, but with direct compression by a fragment of bone. (D) The patient was temporized with an external fixator.

arrives in th e traum a bay with an obvious extrem ity deform ity and a large soft tissue injury, the diagn osis of an open fracture is self-eviden t. However, in th e patien t wh o presen ts with a deform ed extrem ity an d a sm all abrasion or laceration , an open fracture m ay be easily m issed. O pen fractures are con sidered surgical em ergen cies an d require prompt atten tion followin g h em odyn am ic stabilization of th e traum a patien t. In itially, tetan us prophylaxis sh ould be adm inistered if a tetanus booster h as not been given in th e previous 5 years (Table 10.2). In addition , in -

travenous antibiotics should be adm inistered im m ediately upon recogn ition of th e in jury. Followin g diagn osis of an open fracture an d docum en tation of a detailed n eurovascular exam in ation , th e fracture site sh ould be covered with a povidon e-iodin e soaked gauze. Alth ough som ewh at con troversial, open fractures are generally considered a surgical em ergen cy an d sh ould be taken to th e operatin g room with in 6 h ours from th e tim e of in jury for th orough debridem en t an d irrigation . Th e in volved extrem ity sh ould be splin ted appropriately prior to subjectin g th e patien t


199

TABLE 10.2

INDICATIONS FOR TETANUS PROPHYLAXIS Tetanus Immunization (Prior Doses of Tetanus Toxoid)

Tetanus Toxoid

Tetanus Immune Globulin

Tetanus Toxoid

Tetanus Immune Globulin

Uncertain or < 2 2 ≥3

Yes Yes No†

No No No

Yes Yes No‡

Yes No No

Clean, Minor Wounds

Contaminated Wounds

Yes, if wound greater than 24 h old. Yes, if more than 10 yr since last dose. ‡ Yes, if greater than 5 yr since last dose. †

to further im agin g studies (e.g., addition al radiograph s or CT scan s for peri-articular fractures) as well for tran sport to th e operatin g room . Splin tin g m in im izes furth er injury to th e in jured extrem ity, particularly n eurovascular structures that traverse the fracture site and th e soft tissue en velope. O pen fractures are classified on th e basis of th e Gustilo an d Anderson classification. This classification system is based on th e degree of en ergy imparted to th e lim b at th e tim e of the injury. Type I injures are low-energy open fractures and are typically associated with soft tissue defects of less th an 1 cm (Fig. 10.1A). Type II in juries are con sidered to be m edium -en ergy open fractures with an associated soft tissue defect that is usually between 1 and 10 cm (Fig. 10.5A). Type III in juries (Fig. 10.5B) are high-energy open fractures an d are subcategorized on th e basis of th e degree of soft tissue in jury: (A) large soft tissue defect with intact periosteum and m inim al contam in ation; (B) large soft tissue defect with periosteal strippin g, a greater degree of woun d con tam in ation , an d n eedin g addition al soft tissue coverage (e.g., rotation al flap, free flap); an d (C) large

soft tissue defect with an associated vascular injury requirin g repair. Type I an d II open fractures require prompt adm in istration of a th ird gen eration ceph alosporin such as cefazolin. All Type III fractures require the adm inistration of cefazolin plus th e addition of an am in oglycoside such as gen tam icin . Patien ts wh o h ave sustain ed open fractures with severe con tam in ation (e.g., “barnyard’’ injuries) require th e addition of pen icillin to cover gas-form in g bacteria such as Clostridium perfringens. Th e m ajor con cern with open fractures is th e in creased in ciden ce of in fection associated with th ese injuries due to the degree of wound contam ination as well as the degree of soft tissue loss. In itial treatm en t in th e operatin g room en tails th orough debridem en t an d irrigation of th e woun d with delivery of the bony edges of the fracture into the woun d for debridem en t. Th e laceration is typically exten ded in a proxim al an d distal fash ion to gain adequate access to th e fracture site. Depen din g on th e fracture type, th e associated soft tissue defect, an d exten t of wound contam ination, th e treatm en t m ay in clude defin itive plate fixation , in tram edullary (IM) rod fixation , or tem porary stabilization with extern al

A

B Figure 10.5 (A) Open type II tibia fracture with transverse tibial shaft fracture and a wound that

is primarily closeable. (B) Open type III tibia fracture after significant high-energy soft tissue injury with muscle and skin loss.

200


fixation . As m en tion ed above, open fractures associated with a vessel in jury (i.e., type IIIC injuries) m ay require extern al fixation of th e fracture prior to defin itive vascular repair to avoid un due ten sion on th e repair.

FRACTURES WITH NEUROVASCULAR COMPROMISE Gross deform ities of an extrem ity iden tified in a traum a patien t m an date th e docum en tation of a detailed n eurovascular exam ination, especially distal to the site of the deform ity. A patien t wh o presen ts with a n eurovascular deficit distal to an extrem ity in jury sh ould un dergo fracture reduction an d/ or gen tle traction to pull th e extrem ity out to len gth . It is imperative th at a repeat n eurovascular exam in ation of th e extrem ity be perform ed after any m an ipulation of th e in jured lim b. If th e n eurovascular exam in ation return s to n orm al followin g m an ipulation , th e in itial deficit noted on physical exam in ation was likely due to traction or ten sion on th e n eurovascular structures resultin g from th e deform ity. Th e extrem ity sh ould at th is poin t be splin ted appropriately to avoid any addition al un due stress on th e neurovascular structures traversing th e in jury site. Ideally, patien ts sh ould h ave radiograph s obtain ed prior to m an ipulation of any deform ed extrem ity. However, th ere sh ould be n o delay in waitin g for radiograph s if th ere is a n eurovascular deficit in wh ich case m an ipulation sh ould be attempted with out form al x-rays. Followin g m an ipulation , radiographs of th e deform ity site, as well as a joint proxim al an d distal to th e in jury sh ould be obtain ed an d reviewed thoroughly for associated bony in juries. Patients with persisten t neurovascular deficit following m an ipulation of a deform ed extrem ity require addition al evaluation . Nerve deficits sustain ed at th e tim e of in jury are often n eurapraxic in n ature as a result of th e n erve stretch in g. Th ese type of in juries typically are self-lim ited an d m ay take anywh ere from 3 to 6 m on th s to com pletely resolve. Electromyography is th e gold standard to m onitor improvem en t of n erve fun ction an d m ay sh ow activity or improvem en t as early as 6 weeks followin g th e in citin g even t. Fractures th at result from h igh -en ergy in juries m ay result in n erve laceration (Fig. 10.6) an d complete disruption of the neuronal axon s. In this situation, the decision m ay be m ade to explore th e n erve at th e tim e of defin itive treatm en t an d perform a prim ary repair. Vascular deficits th at do n ot return after lim b m an ipulation are con sidered vessel in juries un til proven oth erwise an d require addition al form al studies an d im agin g to con firm th e diagn osis. Th e in itial step is to determ in e th e an klebrach ial in dex. Th is n on in vasive m easure of distal blood flow is don e by m easuring the systolic blood pressure at the level of the elbow and at the ankle. A Doppler signalin g device is typically used to h ear th e pulsatile n ature of arterial flow aroun d each join t. A ratio (in dex) of th e an kle to brach ial pressure of less th an 0.9 is con sidered positive

Figure 10.6 Unstable ankle fracture after a skateboarding acci-

dent resulting in a traumatic laceration of the superficial peroneal nerve (arrow) seen during fixation of the fibula fracture.

an d poin ts in the direction of a vessel injury. In these patients, a m ore form al study is required to identify intim al injures to th e arterial wall versus a complete disruption of the vessel. The findin g of an abnorm al ankle-brachial in dex m an dates an arteriogram th at can be con ducted in an interven tional radiology suite or in the operating room at the tim e of surgical treatm ent of the injury.

SPINAL CORD INJURY A com plete physical exam ination m ust be conducted on all patients with a suspected spinal cord injury as was discussed previously in the evaluation of the traum a patient. Th ere are several spin al cord in jury pattern s th at are associated with predictable m otor and sensory deficits. BrownSequard syn drom e (Fig. 10.7A) is a h em icord tran section , often by a pen etratin g in jury (e.g., knife woun d). An injury pattern of th is n ature results in ipsilateral m otor, proprioception , an d ligh t touch loss with a con tralateral loss of pain an d tem perature sen sation distal to th e in jury level. Cen tral cord syn drom e (Fig. 10.7B) is typically seen in m iddle-aged to elderly patients who h ave preinjury cervical spin e degenerative joint disease. The classic scenario is that of a patien t in volved in a m otor veh icle collision wh o sustain s a hyperexten sion (e.g., wh iplash ) in jury to th e cervical spin e. This in jury pattern results in bilateral upper extrem ity m otor weakness m ore so than bilateral lower extrem ity weakn ess. Cen tral cord syn drom e h as th e greatest poten tial for compete functional recovery when compared with the oth er in jury pattern s. Anterior cord syn drom e (Fig. 10.7C) is usually the result of a vascular in sult to th e an terior spin al cord (an terior spin al artery distribution ). Th e deficit pattern is a loss of bilateral m otor fun ction , pain , an d temperature sen sation


Line of injury

Line of injury

Loss of movement on the same side as cord damage

Loss of movement and sensation

Loss of pain, temperature, and sensation on opposite side

A

201

Incomplete loss

B

Figure 10.7 (A) Brown-Sequard syndrome, (B) central cord syndrome, and (C) anterior cord syndrome with affected anatomical locations. (continued)

distal to th e level of in jury. Th is in jury pattern is associated with th e lowest likelih ood of fun ction al recovery.

FRACTURE-DISLOCATIONS Fracture-dislocation s are fractures th at occur aroun d a join t an d result in a fracture of the bone with an associated dislocation of th e join t. Th is type of in jury h as several variations based on the fracture pattern , the bone that is involved, an d the joint that is in volved. Dislocations in gen eral require prompt reduction due to th e stress im parted on th e traversin g n eurovascular structures an d soft tissue (Fig. 10.8). In addition, joints that are left dislocated for a prolon ged period of tim e, typically m ore th an 6 h ours, are at risk of irreversible cartilage dam age and posttraum atic arthritis of the involved joint. Following reduction of

a fracture-dislocation , th e lim b is splin ted to preven t any furth er dam age or loss of reduction during patient transport. Th ese in juries often requires defin itive operative fixation of th e fracture as well as repair/ recon struction of any associated soft tissue disruption (e.g., ligam en ts). Fractures surroundin g a joint (periarticular fractures), wh eth er associated with a dislocation or not, often require advan ced im agin g to fully delin eate th e in jury pattern . CT scan s are helpful in iden tifying the bony pattern of injury, wh ereas MRI is used to determ ine soft tissue (i.e., ligam ent or ten don ) in juries. MRI is m ore useful wh en delayed treatm en t of th e in jury is un dertaken sin ce obtain in g an MRI in the acute setting usually dem onstrates a great deal of edem a that can obscure soft tissue detail. Advanced im aging and diagn ostic tools m ay be n ecessary in patien ts with abn orm al vascular exam in ation results after dislocation an d reduction given th at m any join ts lie in close proxim ity to vasculature.

202


Line of injury

Loss of movement, pain, and temperature Still able to feel position, vibration, and touch

C

COMPARTMENT SYNDROME Th e ph en om en on of compartm en t syn drom e is a surgical em ergen cy an d requires a h igh in dex of suspicion . Each extrem ity con tain s several m uscles th at are separated by fascial compartm ents. When the pressure within any single or several compartm en ts reach es a level beyon d a th resh old value, th e ven ous return from th e extrem ity is in itially comprom ised. As th e pressure con tinues to increase, the forward arterial flow of oxygenated blood is comprom ised resultin g in in tracompartm en tal m uscle isch em ia. Iden tification of an “impen ding’’compartm ent syndrom e is critical in m in im izin g th e m orbidity associated with irreversible m uscle isch em ia an d even tual m uscle cell death . Th e m ost com m on sites of compartm en t syn drom e in clude th e forearm and th e lower leg (Fig. 10.9A). This phenom enon also can occur with in th e fascial compartm en ts of th e

Figure 10.7 (continued )

th igh , foot, an d th e gluteal m uscles, alth ough m uch less com m on . Compartm en t syn drom e is a clin ical diagn osis. In th e patien t wh o is awake an d alert an d is able to com ply with th e physical exam in ation , th e diagn osis can be m ade clin ically an d usually is lin ked to a h igh in dex of suspicion . Th e followin g patien t scen arios sh ould in crease th e likelihood of the possible diagnosis of compartm en t syndrom e: (1) h igh -en ergy closed fractures; (2) prolon ged extern al pressure on th e compartm en t (e.g., patien ts foun d down for a prolon ged period of tim e); (3) in traven ous ionic dye extravasation (e.g., patients receiving contrast dye for a CT scan th at extravasates out of th e in travascular system in to a fascial com partm en t); (4) crush in juries; (5) reperfusion in juries (e.g., repair of arterial in juries resultin g in recon stitution of blood flow an d th us increased in flam m ation); (6) concom itant arterial and


A

203

B

Figure 10.8 (A) Medial ankle dislocation with fibular fracture and (B) tension-type soft tissue

defect requiring prompt reduction followed by irrigation and debridement with temporizing fixation in the operating room.

ven ous in juries to an extrem ity; an d (7) lim b ischem ia m ore than 6 hours. Th e physical exam in ation in a con scious patien t sh ould begin with evaluatin g for pain with passive stretch of th e distal extrem ity digits. Th is is th e m ost sen sitive test in m aking the clin ical diagnosis of compartm ent syn drom e. For exam ple, a patien t with an impen din g lower leg com partm en t syn drom e following a closed proxim al tibia fracture will presen t with pain out of proportion to wh at would be expected with dorsiflexion of th e toes. In con jun ction with this exam ination fin ding, patients typically exhibit very ten se compartm en ts on palpation an d sign ifican t pain with compression of the involved area. Oth er pertinent physical

fin din gs could in clude pulselessn ess, poikiloth erm ia (cool extrem ity), an d paraesth esias. However, wh en th ese exam in ation fin din gs are presen t, th e diagn osis h as often been m issed an d it m ay be too late to adm in ister effective surgical treatm en t. Th e diagn osis of compartm en t syn drom e is m ore difficult to m ake in the unconscious patient or in the pediatric population . Again , th e m ost im portan t con cept in m akin g the diagnosis, even in th e uncon scious patient, is a high index of suspicion . Specifically in th e pediatric population , even th ough th e ch ild m ay be awake, com plian ce with th e physical exam in ation an d ability to an swer question s m ay be th e lim itin g factor. In addition , th e adm in istration of

Anterior compartment Interosseous membrane

Lateral compartment

Tibia Deep posterior compartment

Fibula

A

Superficial posterior compartment

Figure 10.9 (A) The four compartments of the tibia include the anterior, lateral, superficial posterior, and deep posterior. (B) The anterior and lateral compartments are released through a lateral exposure. The superficial and deep posterior compartments can be released through a medial incision. The incisions should be extensile and should include both skin and fascia.

B

204


Suspected Compartment Syndrome

Unequivocal positive findings

Patient not alert /unconscious/incoherent

Comp. pressure measurement

∆P > 30 mmHg

∆P < 30 mmHg

Fasciotomy Serial exams

in traven ous n arcotic m edication s for pain con trol m ay also obscure th e physical exam in ation fin din gs. In th ose patien ts, wh ere th e in dex of suspicion is h igh but th e physical exam in ation is equivocal, a m ore in vasive diagn ostic m easure, in tracom partm en tal pressure assessm ent, should be perform ed. Several com m ercially available n eedle devices can be used to m easure in tracom partm en tal pressures. In gen eral, a sm all am oun t of salin e is in troduced in to th e com partm en t un der in terrogation th at th en equilibrates with in the compartm ent. The pressure m easurem ent reading is then taken as the pressure within the fascial compartm ent. Typically, th e forearm requires pressure m easurem en t in three separate compartm ents: the flexor compartm ent, the exten sor com partm en t, an d th e m obile wad (fascial com partm en t con tain in g th e brach ioradialis, exten sor carpi radialis lon gus, an d exten sor carpi brevis m uscles). For th e lower leg, th e an terior, lateral, superficial, an d deep posterior fascial compartm ents sh ould be m easured. Each com partm en t m easurem en t sh ould be docum en ted as well as the patient’s diastolic an d m ean arterial pressure (MAP) at the tim e of th e m easurem ent. There are several m easurem en t thresholds that can be used to determ in e wh eth er an in tracom partm en tal pressure is h igh and requires treatm en t. Som e authors recom m en d an absolute value greater th an 30 m m Hg as th e threshold value. The intracapillary pressure required for the forward flow of blood into a fascial compartm ent is 25 m m Hg. Therefore, an intracompartm ental pressure of 30 m m Hg or m ore m ost likely impedes th e forward flow of arterial blood in to th e compartm en t. However, oth er authors have dem onstrated that each compartm ental m easurem ent should take into accoun t th e hem odynam ics of the patien t at the tim e of the m easurem ent. With this

Figure 10.10 Management scheme for a patient with suspected compartment syndrome.

in m ind, an intracompartm ental pressure that is within 40 m m Hg of th e diastolic or MAP of th e patien t sh ould be con sidered a h igh pressure. Regardless of th e tech n ique used to defin e a h igh compartm en tal pressure, th e m eth od sh ould be clearly recorded in the patient record and th e decision m akin g sh ould reflect th e docum en ted pressure m easurem ents or pressure differentials (Fig. 10.10). Measurem ent of elevated com partm ent pressures m andates im m ediate treatm en t, which consists of fasciotomy and com plete release of th e in volved fascial com partm en ts. Surgical release of fascial com partm en ts is n ot a cosm etic procedure (Fig. 10.9B). Extensile incisions are used to release th e fascia under direct visualization to obtain adequate release and avoid inadvertent in jury to th e n eurovascular structures traversin g th e compartm en t. All th ree forearm compartm ents are typically released through a sin gle volar incision whereas the four compartm ents of th e lower leg can be released th rough a single or dual exten sile incision. Following fascial release, the woun d is copiously irrigated and packed open with a wet to dry dressing. In addition , vessel loops stapled to the skin in an interwoven pattern or a n egative pressure wound therapy dressing (vacuum assisted closure dressing) are com m only used in th is settin g. Patien ts are typically taken back to th e operating room every 48 to 72 hours for repeat irrigation an d debridem en t un til th e woun d can be prim arily closed, all n ecrotic m uscle has been th orough ly debrided, an d/or the decision is m ade for addition al soft tissue (split th ickn ess skin grafting) coverage. If compartm en t syn drom e is a possibility given a certain in jury pattern (e.g., closed m idsh aft tibia fracture), th en region al an esth esia, con tin uous epidurals, an d patien t con trolled in traven ous opiate an algesia sh ould be avoided sin ce th ey m ay m ask the symptom s of compartm ent


syn drom e. Missed compartm en t syndrom e in tibia fractures and other surgical patients m anaged postoperatively with th ese tech n iques h ave been reported an d th erefore they are generally avoided.

POLYTRAUMA Th e m an agem en t of th e patien t with polytraum a is a complex interplay of injuries, treatm ent options, and an appreciation for th e complexity of the variability in presen tation . A polytraum a patient is one wh o h as an In jury Severity Score greater th an 18 with m ultiple system in juries. Th ere is a system ic in flam m atory respon se after traum a, wh ich m ay lead to sequelae such as acute respiratory distress syn drom e (ARDS), sepsis, and/ or m ultiorgan failure. Th is h as given rise to th e “two-h it’’th eory. Th e “first h it’’is from the initial stim ulus resultin g in a system ic in flam m atory respon se. Th e “secon d h it’’ com es from a subsequen t proin flam m atory even t such as in com plete resuscitation , excessive blood loss, sepsis, or a surgical procedure. Two in terleukin s h ave been implicated in th e polytraum a patien t— IL-6 as a proin flam m atory cytokin e in creasin g likelih ood of ARDS an d IL-10 as an an ti-in flam m atory cytokin e. Patients at risk include th ose who are clinically unstable, a difficult resuscitation, coagulopathic (platelet count less than 90,000), hypotherm ic (less than 32 ◦ C), in shock, require greater th an 25 un its packed red blood cells, or th ose with bilateral lun g in jury, an d m ultiple long bon e fractures and thoracic or abdom inal in jury. Apolytraum a patient wh o is adequately resuscitated has a n orm al or n orm alizin g lactate, base deficit, or m ixed

205

ven ous oxygen saturation . Th e patien t is adequately rewarm ed with an intern ational norm alized ratio less than 1.25, platelet coun t greater than 90,000, and a cerebral perfusion pressure greater th an 70 m m Hg. However, it sh ould be noted that th ere is a secondary period, wh ere despite appropriate resuscitation , patien ts operated on 2 to 4 days after th eir in itial traum a m ay h ave a worsen in g of their condition (“secon d h it’’). Therefore, significant surgical intervention m ay need to be delayed 5 to 8 days after in jury to th e lim it th e impact of th e “secon d h it’’ (Fig. 10.11). Th is has lead to two sch ools of th ought in th e m anagem ent of the polytraum atized patient—early total care an d dam age con trol orth opaedics. Early total care in volves im m ediate definitive m anagem ent of orthopaedic in juries allowin g for early m obilization and decreased pulm on ary complication s. However, in creased m ortality an d m orbidity h as been associated with early total care in patien ts with ch est traum a. Dam age con trol orth opaedics temporizes fractures with extern al fixation avoidin g th e “second hit.’’ When the patien t is stable, definitive care is un dertaken . In th e m ultiply injured patien t, fat em bolism is an im portan t cause of ARDS an d a m ajor source of m orbidity an d m ortality. It m ay be poten tiated by fracture stabilization with IM n ailin g of lon g bon es. Fat em bolism syn drom e is clinically apparent in 10% of polytraum a patients, although the actual inciden ce rate is probably m uch high er. It m ay n ot appear un til 2 to 3 days after th e in jury an d m ay presen t as respiratory distress (sh ortn ess of breath an d tachypn ea), arterial hypoxem ia, tachycardia, fevers, an d a deterioration of n eurological status (restlessn ess, con fusion , or com a). In addition, petechiae (which m ay be short

Second Hit Phenomenon First Hit (initial trauma) Severe response

Reaction

MOF/ARDS Second Hit (surgical intervention)

Figure 10.11 Damage control orthopaedics is often utilized in patients with thoracic trauma resulting in a proinflammatory state. The “second hit” results in further aggravation of an already heightened inflammatory response and may lead to multiorgan failure.

Resolution

MOF/ARDS

206


lived) can appear across th e ch est an d axilla. Treatm en t consists of pulm onary support and early orthopedic care.

FRACTURE CLASSIFICATION O n ce a fracture h as been iden tified on radiograph s, it is im portan t to be able to con vey th is in form ation to oth ers wh o m ay n ot h ave access to th e im ages. Fracture classification system s serve m ultiple functions including com m unication to oth er m edical profession als about th e severity, location , or com plexity of th e fracture. For example, th e Sch atzker classification for tibial plateau fractures indicates the severity of articular surface in volvem en t an d wh eth er th e diaphysis is associated with th e m etaphysis. Th e classification system m ay also guide treatm en t as is th e case with the Garden classification for fem oral n eck fractures. Garden type I an d type II fractures are con sidered stable an d m ay be addressed with open reduction an d in tern al fixation whereas Garden type III and type IV fractures are displaced requirin g arth roplasty. Certain classification system s m ay porten d progn osis of th e fracture, such as th e Hawkin s classification system for talus fractures. The Hawkin s classifi-

cation ran ges from on e to four, wh ere a type 1 fracture h as a 5% to 10% chan ce of resultin g in avascular necrosis, wh ereas a type IV h as a 90% ch an ce of avascular n ecrosis. Lastly, classification system s can aid in research for study design , describin g results, an d exam in in g applicability of treatm ent interventions. Ultim ately, the utility of a classification system is based on high inter- and intraobserver reliability. A myriad of classification system s exist with in orth opaedics an d it is n ot realistic to m em orize all of th ese system s. Th e m ost widely accepted fracture classification system is th e AO / O TA system , wh ich uses num bers and letters to describe fractures. Each bone h as a num ber (1h um erus, 2-forearm , 3-fem ur, 4-tibia), wh ich is first in the code. Th e secon d n um ber is th e segm en t of th e bon e th at is involved (1-proxim al, 2-diaphysis, 3-distal). The “type’’ of fracture is th en described for diaphyseal in juries (Asim ple, B-wedge, C-com plex) (Fig. 10.12A). If th e fracture is proxim al or distal, th en th e letters represen t extra-articular (A), partial articular (B), or complete articular (C) injuries (Fig. 10.12B). However, n ot all physicians or residen ts m ay be fam iliar with the classification system being used to describe a

A

B Figure 10.12 (A) The tibia fracture would be classified as an AO/OTA type 42A. The classification

would indicate that the fractured bone is a tibia (4), it is midshaft/diaphyseal (2) in location, and is simple (A). (B) The radiograph reveals an AO/OTA type 13C fracture that would indicate humerus (1), distal (3), and complete articular (C) since there is no articular surface attached the shaft and there is a split through the articular surface. Ultimately, using descriptive words is the best way to describe a fracture pattern.


fracture. The best m eth od in com m unicating a fracture pattern is usin g descriptive words about th e location of th e fracture, the angulation, the displacem en t, the direction of the fracture line, and the degree of com m inution.

FRACTURE MANAGEMENT Bone Biology and Physiology Bone h as two m ajor fun ctions. The m ech anical function involves supporting load, allowin g m uscle action, protectin g vital organ s, an d en ablin g locom otion . Th e biologic function includes hem atopoiesis an d the important role of calcium h om eostasis. Alm ost 99% of th e body’s calcium is contained within bone and it is essen tial in Vitam in D m etabolism . In addition , bone is an end organ for parathyroid horm one, calcitonin, growth horm on e, an d corticosteroids—all of which are involved in bon e (and calcium ) regulation. Bone is a composite of two m aterials. Th e organ ic extracellular m atrix (35% dry weigh t) is com posed of collagen an d provides flexibility an d resilien ce. Th e m in eral ph ase is composed of hydroxyapatite (calcium an d ph osph ate) and provides for the hardn ess and rigidity of bon e. Cortical bon e is periph eral an d rem odels slowly due to a poor porosity but is extrem ely stron g. On th e oth er hand, cancellous bon e (m edullary or central) h as 10% of the strength of cortical bone, is spongy, and has porosity between 30% an d 90%. Bone respon ds to stress by altering its m echanical characteristics (Wolff’s law). With increased stress, bone will hypertrophy. Th e contrary is true—decreased stress can lead to increased bone resorption. Un like articular cartilage, tendon, or ligam ent injury, bon e regen erates tissue an d repairs with out scar. Th e blood supply to the cortical bone has two m ain contribution s— the inner two-third of the cortical bone receives its blood supply from the nutrien t vessel, whereas the outer on ethird of cortical bone receives its blood supply from the periosteum (Fig. 10.13).

207

Fracture Healing Fractures occur when the energy of the injury is sufficient to overload the bone resulting in loss of continuity, loss of support, soft tissue dam age, and dam age to the blood supply. Fracture h ealin g requires an adequate biologic en viron m ent (soft tissue, pluripotential cells, and patient factors) and an appropriate m echanical en viron m ent (e.g., fracture stabilization tech n ique). Within the appropriate biological and m echanical environm ent, fractures heal via prim ary or secon dary m odes. Th e biom ech an ics of fracture h ealing involve the am ount of m otion at the fracture site an d th e gap size between th e fractured en ds of th e bon e. Strain in bone is m echanical force producing elongation. Bone form s with low strain across a fracture gap. Low strain and n o gap result in prim ary bon e h ealin g with out callus. Low strain an d a large gap will result in secondary bone healing with callus form ation. Prim ary bone healing is direct rem odelin g of th e fracture th rough rigid fixation . It is also known as a haversian rem odeling or osteon rem odeling and does not result in callus form ation. There is direct contact between bon e en ds with n o m otion (Fig. 10.14). O n th e oth er h an d, secon dary bon e h ealin g (in direct bon e h ealing) results from n onrigid fixation with callus form ation th rough in tram em bran ous an d en doch on dral h ealin g. It sh ould be noted th at in secondary bon e healin g, fragm ent m otion stim ulates callus form ation (Fig. 10.15). However, excessive m otion (or in stability), at critical tim es durin g h ealin g m ay lead to non un ion (Fig. 10.16). Fracture h ealin g occurs in th ree distin ct ph ases— inflam m atory (days), reparative (weeks), and rem odeling (m onths) (Fig. 10.17). The in flam m atory phase results from the torn periosteum , fracture hem atom a, necrotic m arrow and cortex, an d inflam m atory m ediators. Th e pluripoten tial stem cells are locally derived an d result in osteoblast an d osteoclast differen tiation an d proliferation th rough cellular m ediators. Th e repair ph ase organ izes th e h em atom a with early subperiosteal woven bon e and the start of cartilage form ation. Fin ally, woven or fiber bone bridgin g th e fracture gap is replaced by lam ellar bon e th at revascularizes over tim e.

Preoperative Planning

Figure 10.13 Contributions to the blood supply of cortical bone.

Prior to an operation , th e tim e wh ich a surgeon devotes to a careful preoperative plan is of critical im portan ce an d often determ in es th e success or failure of th e procedure. Plan n in g is essential as it allows for com m unication with the anesth esiologist, n ursin g, critical care, an d im agin g tech n ician s. In addition , it allows for an ticipation of problem s, n ecessary supplies, in strum ents, an d implan ts; shortens operating room tim e; and m ay improve outcom es. The basic steps to fracture fixation include the surgical incision, preparation of th e bon e en ds, reduction , temporizin g fixation , defin itive fixation , closure, an d aftercare. Th e com pon en ts of a preoperative plan in clude operatin g room logistics

208

A


B

Figure 10.14 (A) A 42-year-old female with a left spiral fracture of the humeral shaft

C

after fall while on a boat. (B) The oblique fracture was directly stabilized with three lag screws and a neutralization plate. (C) Three months later, the fracture lines are no longer visible and the fracture has healed primarily without callus formation.

209


A

B

C

D Figure 10.15 (A) Anteroposterior radiograph revealing a transverse mid-shaft right femoral shaft

fracture after a motor vehicle collision. (B) The fracture has been stabilized with an intramedullary nail—a relative stability construct. (C) Two months after surgical fixation, the fracture shows brisk callus formation, but the fracture line is still evident. (D) By 6 months, the fracture has completely healed through secondary bone healing.

210


Figure 10.16 A 29 year-old female 2 years status post open

reduction and internal fixation of her left distal humerus fracture. She has a nonunion due to significant motion at the fracture site due to lack of adequate stabilization. The presence of the broken hardware is likely due to the repetitive loading seen by the screws because of the excessive motion and lack of stability.

(room setup), an esth etic type, im agin g, in strum en ts, im plan ts, an d surgical tactic in cludin g m ultiple option s for reduction an d fixation strategy (Fig. 10.18).

Fracture Stabilization In dication s for fracture fixation in clude open fractures, articular fractures, polytraum a, en couragin g patien t m obilization , early join t m obilization , an d correction of align m en t. Th ere are four broad categories of fixation m eth ods to h old a fracture: (1) splin tin g an d castin g, (2) traction , (3)

Intensity of response

Inflammation phase

10%

Reparative phase

extern al fixation , an d (4) in tern al fixation . Th e ch oice of treatm ent depen ds on m any factors, including th e inherent stability of the fracture. For the m ost part, the in itial in jury, particularly th e am oun t of displacem en t an d com m in ution, will determ ine the m axim al degree of fracture instability. Th ere are m any fractures in wh ich splin tin g or castin g is the treatm ent of choice (e.g., clavicle, hum erus, distal radius, an d foot). In addition , m ost pediatric fractures can be treated successfully in a cast because of the rapid healing and rem odeling potential in th at patient population. Wh en splin tin g or castin g a fracture, im m obilization of th e join ts above an d below th e fracture site is critical. Th e m ain disadvan tages of this form of stabilization are the inability to rigidly hold a reduction, joint stiffness from prolonged im m obilization , and the danger of skin ulceration s at bony prom inences. Traction is currently used m ostly in th e lower extrem ity, via lon gitudin al traction th at is applied th rough a pin in serted eith er th rough th e distal fem ur or th rough th e proxim al tibia. It is gen erally used as a tem porizin g m easure in patien ts with un stable fractures wh o can n ot tolerate an operation . Th e m ain drawbacks are suboptim al fracture fixation (with ten den cy for sh orten in g an d rotation al m alun ion ) an d th e n eed for prolon ged im m obilization (m ore th an 6 weeks), which can lead to developm ent of sacral ulcers, joint stiffn ess, an d pneum on ia. Extern al fixation is in dicated in fractures with segm en tal bon e loss, associated vascular in juries, and m assive soft tissue injuries with a high risk of infection (Fig. 10.19). In addition, because of the speed with which it can be applied, extern al fixation is also in dicated in th e m ultiply in jured patien t with extrem ity in juries an d in th e h em odyn am ically un stable patien t (dam age con trol orth opaedics). Th e m ain complications of external fixators are the risk of pin tract in fection and less rigid fixation when compared with internal fixation. Th e five m ain types of in tern al fixation devices are pin s (such as Kirsch ner wires), screws (such as lag screws), plates, IM rods, an d prosth etic replacem en ts. Pin s, wh ich can be in serted percutan eously, are often used to stabilize fractures in the hand and foot and to supplem ent fixation elsewh ere (Fig. 10.20). Lag screws, wh ich provide com pression across a fracture site, are used to fix simple transverse

Remodeling phase

40%

70% Figure 10.17 The bone healing

Time

timeline can be altered by patient factors, severity of soft tissue injury around the fracture bone, infection, and method of stabilization.


A Figure 10.18 (A) Preoperative plan for a complex reconstruction of a (B) mal-united tibial plateau fracture. The preoperative plan is reviewed with the surgical team and posted in the operating room. (continued )

211

212


B Figure 10.18 (continued )

or oblique fractures such as m any fem oral n eck fractures (Fig. 10.21). Plates such as the dyn am ic compression plate an d fixed-an gle plates are useful in lon g-bon e fractures an d provide rigid fixation and compression across the fracture site. Th e IM rod is inserted from one end of a long bone down the IM canal, thus transfixing the fracture site an d providin g tran slational and angular stability. Th e sm aller in cision used to insert the IM rod avoids extensive soft tissue dissection an d allows rapid healing and early return to fun ction . Som etim es th e IM can al is ream ed to allow for insertion of a larger (an d hence, stiffer) rod, an d it is important to note th at there have been reports of em bolization of fat an d m arrow elem en ts durin g IM ream in g an d roddin g. Lastly, prosth etic replacem en t such as th e hem iarth roplasty of the h um eral and fem oral h ead is used in situations in which com m inution of the bone an d cartilage is so severe that anatom ic reduction cannot be restored (Fig. 10.22). Absolute stability results in prim ary bon e h ealing as there is no m otion between the fracture en ds and no callus form ation. The prim e example of an absolute stability construct is lag screw between fractured bone ends, neutralized with a plate. On e th e oth er h an d, relative stability allows for callus form ation with m otion at the fracture site (e.g., IM n ail, extern al fixation , bridge platin g, or castin g).

DIAPHYSEAL FRACTURES Th e fracture pattern , th e degree of soft tissue in jury, an d associated injuries determ ine the treatm ent of diaphyseal

B

Figure 10.19 (A) An anteroposterior radiograph of an open el-

A

bow fracture in 18-year-old patient after a fall from two stories. The patient had a dislocation of the other elbow, an open femur fracture, and bilateral lung injury. He was placed into an external fixator (B) to stabilize his arm and prevent further injury to his soft tissue.


213

Figure 10.22 Anteroposterior radiograph of a left hip revealFigure 10.20 Navicular dislocation after a motor vehicle collision stabilized with multiple Kirschner wires. The entire foot was protected with an external fixator.

(long bone) fractures. The fracture location is generally described as diaphyseal, m etaphyseal, or in tra-articular, wh ereas th e fracture pattern is described as tran sverse, oblique or spiral, sim ple, or com m in uted. Diaphyseal frac-

Figure 10.21 Lateral hip radiograph revealing lag screw fixation of a valgus-impacted femoral neck fracture in an elderly patient.

ing a hemiarthroplasty for a displaced femoral neck fracture in an elderly patient.

tures occur when energy imparted to th e extrem ities cannot be dissipated in th e soft tissues. Com m in uted fractures are m ore likely with open fractures due to the higher energy required to create th ese in juries. Th e type an d rate of stress loading determ ine the fracture pattern. Slow torque causes a spiral fracture, wh ereas a h igh -en ergy, direct blow causes a com m inuted transverse fracture. Splin ts are used for in itial im m obilization because of th eir ease of application an d ability to readily reassess th e in jury. Im m obilization , traction , extern al fixation , an d a variety of techn iques of intern al fixation are used for defin itive stabilization . If casts are applied for defin itive treatm ent, they m ust im m obilize the join t above and below the fracture. Complications from casting in clude cast burn s an d com partm en t syn drom es. Both com plication s are m ore likely to occur in the unconscious or insensate patien t wh o can n ot com plain of pain . Skeletal traction in volves th e application of lon gitudin al stabilization forces usin g a pin or wire through bone distal to the fracture site. Currently, the trend is to use skeletal traction only in the prelim inary treatm ent of som e fractures in adults until definitive stabilization m ay be completed. One reason for th is is th at prolon ged skeletal traction is n ot con ducive to early m obilization . In con trast, extern al fixation of diaphyseal fractures is a defin itive, percutan eous stabilization technique that allows rapid stabilization of a fracture without furth er soft tissue injury resulting from open

214


B

A Figure 10.23 Anteroposterior view of the left femur (A) with an oblique distal femoral shaft frac-

ture treated with bridge plating (B). Callus forms secondary to the relative stability fixation construct. If a lag screw had been placed across the fracture site to create absolute stability, the fracture would have healed without callus.

surgery. Th is techn ique also avoids th e implantation of hardware at a site that is at risk for bacterial colonization and in fection . Fin ally, extern al fixation facilitates woun d care an d patien t m obilization . However, extern al fixation h as been sh own to be associated with pin tract in fection s an d in creased rates of m alun ion , n on un ion , an d delayed un ion . Internal fixation h as been advocated in the orthopaedically in jured patien t because it perm its in direct reduction of th e fracture, early m otion of join ts, an d patien t m obilization . Th e latter improves pulm on ary toilet, decreasin g the risk of infection, and reduces th e risk of deep ven ous throm bosis. A disadvantage of internal fixation is th e requirem en t for surgery, with addition al tissue traum a an d blood loss. In tern al fixation with IM roddin g m ay disrupt the endosteal blood supply to the bone. Relative stability con structs are en couraged for diaphyseal fractures, which lim it disruption of the periosteal blood supply. Th e goal of fracture fixation in diaphyseal fractures is restoration of len gth, alignm ent, and rotation. Fracture h ealin g occurs th rough callus form ation as a result of relative m otion at the fracture site. Fracture fixation tech n iques prom otin g a relative stability con struct in clude bridge platin g (Fig. 10.23) an d IM n ailin g.

ARTICULAR FRACTURES Articular cartilage is composed of water (65% to 80%), proteoglycan s, type II collagen , an d ch on drocytes, wh ich are respon sible for th e resilien ce, elasticity, an d compressive resistance of the joint surface. Articular cartilage is avascular, an eural, an d sen sitive to in jury with lim ited h ealin g poten tial as n utrition occurs th rough diffusion durin g m otion an d gen tle loadin g.

In tra-articular fractures result in ch on drocyte in jury or death wh ere collagen is broken , proteoglycan is lost, an d subchon dral bon e is fractured. Studies have shown th at th ere is lower proteoglycan syn th esis an d h igh er water con ten t in areas of direct impact with possible irreversible cartilage dam age occurring even after a single high-energy impact load. Cartilage and bon e disruption (osteochondral fracture) results in th e form ation of a fibrin clot, in flam m ation, in vasion of n ew cells, an d production of n ew chon dral and osseous tissue. Depending on the location and size of the lesion and th e structural integrity, stability and align m ent of the joint, the repair tissue m ay rem odel and serve as a functional join t surface, or it m ay degen erate. Th e treatm en t prin ciples associated with articular fractures include anatom ic reduction, absolute stability, restoration of axial align m en t, an d early join t ran ge of m otion (Fig. 10.24). Research has shown that n onanatom ically reduced or noncompressed fractures heal with fibrocartilage only, as opposed to hyalin e cartilage. In addition, improper align m ent of th e m echanical axis alters load transm ission an d accelerates joint degeneration. Early join m otion increases cartilage nutrition through im bibition, improves ran ge of m otion, and m aintains m uscle tone. Th e foundation of absolute stability, wh ich is the dictum in obtain in g prim ary bon e h ealin g in articular fractures, is th e placem en t of a lag screw.

PELVIC RING INJURIES Th e pelvis is th e supportin g structure for th e periton eal con ten ts an d retroperiton eal structures. It con n ects th e appen dicular skeleton to th e axial skeleton . Because th e pelvis lies

215


A

B

Figure 10.24 An anteroposterior radiograph of the knee after an

C

assault revealing a bicondylar tibial plateau fracture (A). An axial view on the CT scan shows significant articular depression on the lateral side and a posteromedial fracture line (B). Treatment includes anatomic rigid surgical stabilization when the soft tissue is amenable with early range of motion and no weightbearing for 12 weeks (C).

in close proxim ity to vessels, the colon, and gen itourinary structures, pelvic in juries can be associated with retroperiton eal bleedin g an d n eurologic, bowel, an d bladder in juries. Th e pelvis is m ade of th ree bon es—two in n om in ate bon es an d th e sacrum —con n ected by a n um ber of ligam en ts including the symphyseal ligam ent an teriorly and the posterior an d anterior sacroiliac ligam ents posteriorly. Th e sacrum an d posterior rin g are critical to th e overall stability of th e pelvic rin g as th e sacrum is th e “keyston e’’ to m ain tain ing the biom ech anics of ring congruity through force tran sm ission.

Pelvic fractures m ay be defin ed as stable, rotationally un stable, or rotation ally an d vertically un stable. All un stable in juries in volve disruption of th e posterior portion of the pelvic ring. Unstable pelvic fractures result from highen ergy in juries in th e settin g of m ultiple traum a an d are associated with 50% m ortality in the m ultiple traum a patient. Th ey require rapid assessm en t for stabilization an d triage. Mech an ism of in jury an d h istory are essen tial, if th ey can be obtain ed from th e patien t. Physical exam in ation sh ould in clude a full traum a survey, including a through neurologic exam in ation . Th e an terior an d posterior pelvis sh ould be

216


in spected for open woun ds. In m ales, th e scrotal con ten ts are palpated for testicular displacem en t an d th e pen ile m eatus is exam in ed for blood, wh ich would suggest ureth ral in jury. Rectal exam in ation is completed for assessm en t of

possible laceration an d prostate displacem en t. Fem ale patients sh ould undergo both bim anual and speculum exam inations to rule out vaginal, urethral, and bladder injury. Vaginal or rectal laceration requires specific treatm ent.

Check airway Oxygen suction, position: intubation: cervical spine control

Injury

Check breathing Chest tubes; oxygen

Check circulation IV lines, crystalloid blood; control external loss; abdominal assessment: pelvic assessment for instability

Hemodynamically stable, with stable pelvis

Hemodynamically unstable, with unstable pelvis

Hemodynamically unstable, with stable pelvis

Hemodynamically stable, with unstable pelvis

Blood replacement

Continue assessment and treatment

Continue assessment and treatment

Cervical spine, chest. AP spine radiographs

Circumferential pelvic compression

Peritoneal lavage

Urgent transport to OR

Operative fixation of pelvis for patient mobility

Patient Stable External fixation of pelvis

positive

Peritoneal lavage positive

negative

Laparotomy

Laparotomy

negative patient still unstable

Patient Stable

patient still unstable Pelvic packing; no coagulopathy

Rule out coagulopathy, other injury; continue with replacement

No coagulopathy: other cases

patient still unstable Angiography

Large vessel disorder

Small vessel disorder

Surgical control

Embolization

Patient Stable Figure 10.25 Pathway for management of pelvic ring injuries based on varying hemodynamics. AP, anteroposterior IV, intravenous; OR, operating room.


Pelvic ring injuries as a cause of hypotension (resulting in acidosis and hypotherm ia) in the h em odynam ically un stable traum a patient require prom pt diagn osis an d treatm ent. Reducing the volum e of th e pelvis is often effective in tamponading pelvic bleeding, which m ost com m only is from a venous source (i.e., large pelvic veins). Posterior pelvic disruption can result in 3 to 4 L of blood loss an d hem odynam ic instability. Concom itan tly, aggressive intravenous resuscitation is necessary an d m ay require blood product adm in istration to ach ieve adequate h em odyn am ic stability. Patients wh o respond to resuscitation sh ould be optim ized with respect to th eir h em odyn am ic status. Patien ts wh o do n ot respon d to resuscitative efforts sh ould be con tin ually re-evaluated to avoid a m issed diagn osis for th e un derlyin g hypoten sion . If th e workin g diagn osis rem ains hypotension secondary to pelvic ring disruption, th en th e algorith m ic approach for th ese patien ts calls for

217

an giography of th e pelvic vasculature after adequate reduction in pelvic volum e. In th is scen ario, a “blush ’’ or active arterial bleedin g source m ay be iden tified via an giogram an d em bolized at th e tim e of th e study (Fig. 10.25). Th e m ost com m on source of arterial bleedin g in th e pelvis is in jury to the superior gluteal artery. Based on th e fracture pattern, the acute treatm ent in the resuscitation bay m ay differ, but typically, a circum feren tial bin der (bed sh eet, com m ercially available wrap [e.g., T-pod]) is placed around the pelvis and greater trochanters to reduce th e in trapelvic volum e (Fig. 10.26). It is imperative th at th e com m ercially available bin ders be assessed for soft tissue pressure n ecrosis after 24 to 28 hours of application. Pneum atic antish ock garm ents have been used in cases of shock with pelvic fractures, but their use rem ains controversial because of complications and the difficulties they present in exam in ation and treatm ent of the patient.

A

B

Figure 10.26 (A) Pelvis radiograph showing disruption of the

C

pelvic ring including fractures of the sacrum, injury to both sacroiliac joints, and separation of the pubic symphysis. (B) Clinical picture of a commercially available circumferential binder stabilizing the pelvis and (C) reducing the intra-pelvic volume by restoring the anatomic relationship of the bones.

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Complication s of pn eum atic an tish ock garm en ts in clude lactic acidosis, cardiac collapse after deflation , diaph ragm atic h ern iation , an d lower extrem ity compartm en t syn drom e. An oth er option for th e extrem ity m an agem en t of bleedin g associated with pelvic fractures is percutan eous extern al fixation . Extern al fixation is a temporary m easure before defin itive open reduction an d in tern al fixation . If pelvic stabilization is n ot possible or bleedin g con tin ues despite application of extern al fixation , an giography an d em bolization are th erapeutic altern atives. Radiographic assessm ent includes an an teroposterior (AP) view of th e pelvis, alon g with in let an d outlet views. Radiograph ic un derstan din g th e pelvic rin g can be difficult as th e pelvis n orm ally sits obliquely wh en a person is in supin e position. Further evaluation of identified fractures is obtain ed with pelvic CT, an d a cystogram an d retrograde ureth rogram m ay also be in dicated. If a bilateral posterior ring injury is identified (i.e., sacral fracture on th e left an d sacroiliac joint disruption on the right, bilateral sacral fractures, etc.), it is im perative th at a lateral im age of th e pelvis be obtain ed to assess th e sacrum for kyph otic deform ity an d possible cauda equin a type symptom s (Fig. 10.27). The patient with an unstable pelvic fracture is often adm itted to th e in ten sive care un it (ICU) after temporary stabilization of th e pelvis. Th e use of a circum feren tial bin der, alth ough often adequate to reduce th e fracture an d con trol bleedin g, does n ot provide extraordin ary m ech an ical stability. Caution m ust be exercised in m obilizin g th e patien t with th is as th e sole stabilization given the potential for resumption of bleedin g with disruption of any clot. Vigilance in assessm en t of associated in juries sh ould be m ain tain ed un til th e patien t h as stabilized. Two m ajor classification system s have been used for describing pelvic ring injuries. The tile classification is based on stability with a type A bein g con sidered stable, a type

Figure 10.27 Sagittal reconstruction view of the posterior pelvic

ring revealing severe kyphotic deformity of the sacrum after a threestory fall. The patient had fracture through the left and right sides of the sacrum connected in the middle—spondylopelvic dissociation. The physical examination findings included bilateral lower extremity numbness with no bowel or bladder function.

B partially stable, an d type C bein g un stable. Youn g an d Burgess suggested a classification system th at used m echan ism of in jury as th e basis for description of th e fracture. In th eir sch em a, specific fracture pattern s were presen t on the basis of the direction of force applied to the pelvis an d included AP, lateral compression, and vertical sheer. AP injuries resulted from direct force against th e anterior or posterior aspect of th e pelvis an d were associated with sign ifican t blood loss (Fig. 10.28A). Lateral com pression in juries com m on ly occurred with a directed lateral blow to the pelvis as would be expected in a “T-bone’’type m otor veh icle collision . Lateral compression in juries h ave the high est associated rate of coup-coun tercoup h ead in juries due to the m echanism of injury (Fig. 10.28B). Vertical sheer fractures are an internal fracture-dislocation of the hem ipelvis with th e h igh est rates of associated n eurologic in jury as well as visceral in jury (Fig. 10.28C). In addition to th e pelvic rin g, Den is developed a classification for the sacrum to predict neurologic injury. The classification is based on the location of the fracture lin e relative to th e sacral foram in a (Fig. 10.29). Zon e 1 fractures are across sacral ala and can cause L5 nerve root im pin gem en t, but on ly about 6% of th ese patien ts will h ave n eurological in juries. Zon e 2 fractures occur th rough the n euroforam ina an d can cause un ilateral sacral an esthesia. If fracture fragm en ts are presen t with in th e n eural can al, this in jury pattern requires operative debridem ent of the fracture fragm ents (usually through a posterior exposure) prior to reduction an d fixation . Fractures th rough th e sacral body are in zon e 3 an d are associated with th e h igh est in cidence of injury to cauda equina with the potential for n eurogenic bladder. More th an 50% of th ese patients will sh ow n eurological in juries. O n ce patien ts are stabilized h em odyn am ically, th ey sh ould return to th e operatin g room for defin itive care of un stable pelvic fractures. Stabilization of th ese fractures leads to earlier patient m obilization, m in im izes the risk of pulm on ary com plication s, decreases ven tilator tim e, an d improves m orbidity and m ortality. Stabilization of the anterior aspect of th e pelvis in cludes defin itive extern al fixation , platin g of the symphysis pubis, or fixation of the ram i. Posterior stabilization can be ach ieved th rough a variety of m ean s in cludin g open reduction an d in tern al fixation , percutaneous iliosacral screw fixation, ten sion ban d platin g, tran siliac com pression rods, an d in th e case of spon dylopelvic dissociation (bilateral sacral fractures) with lum bo-pelvic fixation (Fig. 10.30). After stabilization of fractures, one should aggressively m obilize the patient as m uch as possible given the stability of th e pelvic recon struction . Large forces occur across th e pelvis because it serves as a platform for tran sm ittin g th e lower extrem ity forces to th e torso. Often patients with pelvic fracture are un able to am bulate im m ediately. Th is is n ot on ly because of th e severe n ature of th ese in juries, but also because of the associated injuries. Mobilization starts with ran ge of m otion exercise to th e extrem ities as soon as possible after injury. This is followed with upright sitting


219

B

A

Figure 10.28 (A) Anteroposterior (AP) pelvis of a 32-year-old

male involved in a head-on motor vehicle collision resulting in an AP compression type pelvic ring injury with symphyseal disruption and bilateral sacroiliac joint injury. (B) Lateral compression pelvic ring injury in a 41-year-old female struck by a motor vehicle. The entire right hemipelvis is internally rotated. (C) Vertical sheer pelvic ring injury on the left secondary to being thrown by a horse in a 17-year-old female.

C

1

2

3

Figure 10.29 Denis classification of sacral fractures based on the position of the fracture line relative to the sacral tunnels.

and tran sfer to a chair. Am bulation is advanced depending on th e pelvic stability an d oth er in juries. After pelvic stabilization, the patient is subject to norm al orthopedic postoperative complications directly related to treatm ent, such as infection (5% to 50% based on operative procedure), loss of fixation , m alun ion , an d n on union (10% to 15%). In addition , th ere are m ore severe com plication s specific to th ese in juries, wh ich in clude n eurologic im pairm ent, pulm on ary em bolism , an d sepsis. Neurologic deterioration occurs in 2% to 5% of pelvic fractures. It is m ost frequently due to nerve root traction or avulsion . Th erapeutically, th e patien ts are in itially treated with observation . Electrodiagn ostic studies (electromyography an d n erve con duction testin g) are typically con sidered at approxim ately 4 weeks after in jury to h elp determ ine the long-term treatm ent plan. Residual pain despite fixation can be as high as 30%. Pelvic traum a predisposes th e patien t to deep ven ous th rom bosis, an d prophylaxis for pulm onary em bolism m ust be adm inistered. However, because an ticoagulan ts m ust be used with caution in th e

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A

B Figure 10.30 (A) Anteroposterior (AP) pelvis radiograph after fixation of a type C or AP com-

pression type pelvic ring injury with open reduction and internal fixation of the pubic symphysis and percutaneous iliosacral screw lag fixation of the posterior ring. (B) Percutaneous fixation of the pelvic ring anteriorly and posteriorly after a fall from 50 feet. In addition, the patient had lumbopelvic stabilization due to multiple fractures through the sacrum.

setting of severe retroperitoneal bleedin g, a ven a cava filter is often placed an giograph ically to preven t pulm on ary em bolism .

Open Pelvic Fractures O pen pelvic in juries are associated with h igh -en ergy traum a an d h ave h igh er m orality rates th an do closed in juries. In itially, th ese open in juries are life th reaten in g because of bleeding, but later they becom e potential sources of deep-seated in fection . Greater risk for in fection is associated with disruption of the bladder and urethra as well as rectal an d vagin al laceration s. Urologic in juries are gen erally treated with urin ary diversion an d rectal laceration s with a divertin g colostom y, wh ereas vagin al injuries are treated in an open procedure. Th ese m easures, alon g with an tibiotic th erapy an d surgical debridem en t, can decrease the risk of deep abscess, osteomyelitis, and sepsis.

ACETABULAR FRACTURES After em ergen t resuscitation of the traum a patient who poten tially h as an acetabular fracture, assessm en t in cludes a careful physical exam in ation and review of relevan t radiograph s. A physical exam in ation focusin g on th e acetabular in jury sh ould in clude a well-docum en ted, complete n eurologic assessm en t of th e pelvis an d lower extrem ity, evaluation of th e soft tissues in th e troch an teric an d gluteal region s, an d th e restin g position of th e leg. Because th e sciatic nerve is dam aged in as m any as 20% of acetabular fractures th at in volve th e posterior wall or colum n , th e m otor an d sen sory fun ction of th e extrem ity m ust be care-

fully docum ented. In particular, because the peroneal division is m ost at risk, foot dorsiflexion an d eversion m ust be tested. Closed soft tissue in juries m ay occur about th e h ip region, especially over th e trochanter. A closed degloving injury is referred to as a “Morel-Lavallee lesion .’’Th e serosanguineous fluid collection s that develop in these cavities are culture-positive in as m any as 31% of cases. If th is in jury pattern is discovered, irrigation an d debridem en t of th ese areas sh ould be perform ed, and intern al fixation sh ould be delayed un til th e area is clean . Plain -radiograph ic assessm en t of a patien t with an acetabular in jury begin s with th e five stan dard views of th e pelvis: AP, iliac oblique, obturator oblique, in let, an d outlet (Fig. 10.31). These views will delineate associated pelvic fractures, fem oral h ead injury, and h ip dislocations. The standard AP radiograph is usually sufficient for recognition an d classification of an acetabular fracture. However, th e 45-degree oblique (Judet) views are n eeded to fully characterize the fracture and to determ ine whether there is subluxation of th e h ip join t, wh ich m ay not be visible on th e AP view. Th e obturator oblique view is taken with th e affected side of th e patien t rotated 45 degrees forward. Th is allows clear visualization of th e an terior colum n in th e region of th e h ip, th e posterior wall, an d any posterior subluxation of th e h ip. Th e iliac oblique view is taken with th e un affected side of th e patien t rolled 45 degrees forward. Th is view profiles the posterior colum n from th e n otch to th e isch ium and th e an terior wall, wh ich is curvilin ear and shallower than the posterior wall. Th e inlet and outlet pelvic radiograph s m ay depict pelvic in juries th at would affect th e m an agem en t of th e acetabular fracture. Occasionally, anterior sacroiliac joint widening is presen t


221

A B

C

D

Figure 10.31 Standard radiographic views in a pelvic ring in-

E

jury or acetabular fracture include (A) anteroposterior, (B) obturator oblique of the right acetabulum (and iliac oblique of the left acetabulum), (C) iliac oblique of the right acetabulum (and obturator oblique of the left acetabulum), (D) inlet, and (E) outlet.

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Anterior wall

Posterior wall

Anterior column

Posterior column

Transverse

Anterior column plus posterior hemitransverse

Posterior column plus posterior wall

Transverse plus posterior wall

Figure 10.32 Letournel acetabular fracture clas-

T-shaped fracture

Both column fracture

sification. (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown C, et al. Rockwood and Green’s Fractures in Adults. 7th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2010.)


with tran sverse an d both -colum n acetabular fractures an d this m ay be difficult to appreciate on the standard AP view. A computed tom ograph ic study with fin e cuts (1.5 or 2 m m ) through the affected area of the acetabulum allows m ore precise definition of the fracture than is possible with plain radiography. Two-dim ensional an d th reedim en sion al recon struction s of th e fracture often h elp in un derstan din g th e rotation al deform ities of displaced fractures but are not necessary for decision m aking or operative planning. The inform ation com m only available from the standard radiographic series allows classification of the fracture and defin ition of m any associated variables affecting outcom e. Th e classification of acetabular fractures was stan dardized by Letourn el (Fig. 10.32). He described five elem en tary and five associated fracture patterns. The five elem en tary fractures h ave a sin gle fracture lin e th rough the acetabulum : posterior wall, posterior colum n, anterior wall, anterior colum n, and transverse (through both the

223

posterior an d an terior colum n s). Th e five associated pattern s in volve m ultiple fracture lin es: posterior wall + posterior colum n , tran sverse + posterior wall, an terior colum n + posterior h em itran sverse, T-type, an d associated both colum n. The associated both colum n is a unique fracture pattern , wh ich is differen t th an th e oth ers with in th e Letourn el classification system because th e associated both colum n has n o single piece of articular surface attached to the pelvis; that is, the entire acetabulum is dissociated from the stable pelvis (Fig. 10.33). The various fracture patterns h ave relevance to treatm en t altern atives an d progn osis. In dication s for n on operative m an agem en t of acetabular fractures in cludes an in tact superior acetabular dom e, based on th e th ree stan dard roof arc m easurem en ts (wh ich sh ould be greater th an 45 degrees), or fractures, which sh ow con gruency. Location of th e fracture lines will also porten d n on operative treatm en t if th e fracture lin e does n ot involve th e weigh t bearin g don e or on ly th e pubic portion of th e an terior colum n . Surgeon s advocate early touch

A

B

C

D Figure 10.33 (A) Anteroposterior (AP), (B) obturator oblique, and (C) iliac oblique of a both

column acetabular fracture showing no portion of the articular surface attached to the stable pelvis. The patient was initially placed into skeletal traction and then had an open reduction and internal fixation (D) performed through a Stoppa exposure with a lateral window.

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TABLE 10.3

SURGICAL EXPOSURES FOR ACETABULAR FIXATION Surgical Exposure

General Indications

Fracture Patterns

Complications

Kocher Langenbeck

Posterior column and posterior articular surface

Posterior wall Posterior column Transverse Transverse with posterior wall Some T-shaped fractures

HO: 8%–25% Sciatic nerve palsy: 3%–5% Infection: 2%–5%

Ilioinguinal

Anterior column and anterior articular surface

Anterior wall Anterior column Transverse with Anterior displacement Anterior column/posterior hemitransverse Associated both column

Lateral femoral cutaneous nerve dysesthesia (80%–90% returns by 1 year) HO: 2%–10% Femoral nerve palsy: 2% Infection: 2%–5%

Extended iliofemoral

Maximal simultaneous access to both columns

Transtectal transverse/posterior wall T-shaped fractures Greater than 21 days following injury Inability to reduce posterior column through ilioinguinal Associated SI joint disruption

Infection: 2%–5% Sciatic nerve palsy: 3%–5% HO: 20%–50%

down m obilization for a m in im ally displaced acetabular fracture, as long as there is close radiographic follow up. Surgical m an agem en t of acetabular fractures is tech n ically dem andin g and h as m any poten tial complications. Th e goal of surgery is to accurately restore th e an atom ic configuration of th e joint surface, as well as congruence an d stability of th e h ip join t, wh ile avoidin g complication s. Th e results after surgery correlate m ost closely with the quality of the reduction. In dications for open reduction an d in tern al fixation of acetabular fractures in clude articular displacem en t of m ore th an 2 m m or persisten t displacem en t followin g closed reduction , a n on con cen tric reduction after dislocation of th e h ip out of traction (on any radiographic view), any intra-articular loose bodies associated, an un stable fracture of posterior acetabular wall, lack of parallelism between th e fem oral h ead an d acetabular roof, m edial fem oral h ead subluxation , or in stability out of traction after closed reduction . After surgical stabilization , early postoperative m obilization with ran ge of m otion an d touch -down weigh t bearin g is en couraged. Factors th at are predictive of outcom e in clude in jury to cartilage or bone of fem oral head, an atom ic reduction , and age of patien t. In treatin g acetabular fractures, a sin ge surgical exposure is preferred (see Table 10.3). O f n ote, th e surgical windows in the ilioinguinal exposure are lateral, m iddle, an d m edial. Th e lateral win dow allows access to th e in tern al iliac fossa, th e sacroiliac join t, an d th e upper on ethird of the pelvic brim . Th e m iddle window accesses the quadrilateral surface, th e an terior rim , an d th e pelvic brim from th e sacroiliac joint to the pectineal em inence. The m edial win dow accesses th e superior pubic ram us an d th e symphysis pubis. More recently, auth ors have advocated the use of the m odified Stoppa exposure (Pfannenstiel

incision allowing intrapelvic access to the sacroiliac joints posteriorly) in con jun ction with th e lateral win dow of an ilioinguinal exposure in lieu of the ilioinguinal approach.

Posterior Wall Fractures Posterior wall fractures are the m ost com m on type of acetabular fractures an d comprise approxim ately 50% of all acetabular fractures (associated an d elem en tary patterns) in m ost published series. The am ount of injury to the posterior wall will typically be dictated by such factors as m ech an ism of injury, position of the fem oral head within the acetabulum at the tim e of injury, position of the lower extrem ity at tim e of impact, patien t age, bone quality, an d en ergy im parted. Posterior wall fractures are som etim es colloquially referred to as “dashboard injuries.’’Posterior wall fractures are associated with posterior dislocations of the h ip join t between 40% and 70% of th e tim e in various series (Fig. 10.34). An isolated posterior wall fracture can be classified as an “elem entary’’ fracture pattern in the JudetLetournel classification of acetabular fractures. Posterior wall fractures can also occur as a part of m ore complex fracture patterns, so when a posterior wall fracture is detected, the entire pelvic ring should be assessed. The posterior wall can be best visualized on an obturator oblique radiograph of th e pelvis (Fig. 10.35). An isolated fem oral h ead dislocation without an associated fracture of the posterior wall is a rare occurrence (10% in th e highest series). More often, dislocation of th e fem oral h ead results in a fracture of th e posterior wall (ten sion -type failure). If radiograph s reveal a fracture-dislocation of the fem oral head with an associated posterior wall fracture, then an im m ediate attempt at a closed reduction is warranted (Fig. 10.36). Posttraum atic


Figure 10.34 Anteroposterior (AP) pelvis of a 19 year-old male

involved in a motor vehicle collision while riding his bicycle. The right hip is posteriorly dislocated and the posterior wall fragment is displaced (arrow).

injury to th e sciatic nerve can occur up to 30% of the tim e with a posterior wall fracture-dislocation . Treatm en t in volves open reduction and internal fixation of the unstable posterior wall com pon en t (Fig. 10.37).

TRAUMATIC AMPUTATION Traum atic amputation is defined as a loss of a digit(s) or lim b due to a traum atic in jury. Tech n ical advan ces in m icrovascular surgery have m ade replan tation a com m on treatm ent of upper extrem ity traum atic amputations, and

Figure 10.35 Obturator oblique of the right acetabulum in a

32-year-old female after a motor vehicle collision postreduction revealing a posterior wall fracture.

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surgical success of th ese procedures continues to be en h an ced with m odern tech n iques. Sim ilar in jury pattern s for the lower extrem ity often do not result in replantation due to th e excellen t outcom es with prosth etic use followin g below th e kn ee am putation . Th e m ost importan t factor determ in in g wh eth er a digit or lim b can be replan ted is th e isch em ia tim e, warm or cold. Warm isch em ia tim e is th e tim e th e extrem ity distal to th e injury site has been without blood flow with a norm al temperature and m etabolic rate. Cold isch em ia tim e is defined as the tim e the extrem ity distal to the injury site h as been with out blood flow with a reduced m etabolic rate due to lowerin g th e tem perature of th e tissues. A patien t with a traum atic amputation sh ould h ave th e amputated lim b wrapped in m oist gauze and placed in a bag, which is subsequen tly placed on ice to reduce the m etabolic rate. If th e amputated lim b is placed directly on ice, th ere is an increased risk for frost bite as well as severe skin m aceration, potentially ren derin g the lim b useless for replantation. In general, warm ischem ia tim e sh ould be less than 6 h ours an d cold isch em ia tim e sh ould be less th an 12 h ours. Sm aller lim bs, such as a digit, m ay still be viable at 12 and 24 hours of warm and cold isch em ia tim e, respectively. Th e gen eral sequen ce of replan tation com m en ces with bony fixation , exten sor ten don an d flexor ten don repair, arterial repair, nerve repair, and lastly venous repair. Im m ediate postoperative care requires elevating the replanted lim b, elevating the temperature of th e room environm ent, and avoidance of n icotine and caffeine, which m ay cause arterial constriction. In the event of significant venous con gestion , leech es m ay be placed on th e lim b to relieve con gestion via th e secretion of th e an ticoagulan t h irudin . Comprom ise of the arterial inflow to the lim b warrants reexploration with in 48 h ours followin g replan tation . Th e use of aspirin , dipyridam ole (Persan tin e), low-m olecularweigh t dextran , h eparin , an d sym path etic blockade m ay also m in im ize the risk for arterial throm bosis an d spasm . Determ in in g th e viability of a lim b for salvage is an extrem ely daunting task. The decision to acutely amputate a lim b sh ould be groun ded on as m uch clin ical data as possible, sh ould be life savin g, an d sh ould on ly h appen with docum en tation from two services (e.g., orth opaedic surgery an d gen eral surgery, or orthopaedic surgery and vascular surgery, etc.) detailing the n eed for the acute am putation . In addition , ph otograph s of th e lim b sh ould be recorded in th e m edical record (Fig. 10.38). Scorin g system s h ave been developed to h elp assist with determ in in g th e viability of lim b salvage versus lim b amputation . Th e m ost com m on scorin g system used is th e Man gled Extrem ity Severity Score (MESS) (Table 10.4). Earlier studies sh owed th at an MESS score of greater than or equal to 7 had a 100% predictable value for amputation. Th is relatively simple, readily available scoring system of objective criteria was h igh ly accurate in discrim in atin g between lim bs th at were salvageable an d th ose th at were un salvageable

226


Hip dislocated?

yes

Urgent reduction under sedation?

no

Gross hip instability?

yes

Surgical stabilization

no

Hip reduced?

yes

no

Evolving neurologic injury?

yes


no Surgery for urgent reduction

Distal femoral traction

Intraarticular fragments?

yes


no Definitive stabilization Nonconcentric reduction

yes


yes


no Greater than 2 mm step-off in weightbearing region

no Nonoperative management

Figure 10.37 Obturator oblique of the left acetabulum after

posterior wall fixation using a buttress plating technique to provide absolute stability and direct compression at the fracture site.

Figure

10.36 Management of posterior wall

fracture-dislocations.

an d better m anaged by prim ary amputation in these underpowered studies. More recen t data from th e m ulticen ter, prospective Lower Extrem ity Assessm en t Program (LEAP) study h ave shown lim ited utility of scorin g system s in outcom es of eith er lim b salvage or lim b amputation . Th e clinical utility of five lower extrem ity injury-severity scoring system s was also assessed in th e LEAP study. Scoring system s for lower-extrem ity traum atic injuries design ed to assist in th e decision -m akin g process were used to evaluate 546 patien ts—407 lim bs rem ain ed in th e salvage path way 6 m on th s after th e in jury. Th e an alysis did n ot validate th e clinical utility of any of the lower-extrem ity injury-severity scores. However, a h igh specificity of the scores in all of the patient subgroups did confirm that low scores could be used to predict lim b-salvage potential. Yet, the con verse was not true—low sensitivity of th e indices failed to support th e validity of th e scores as predictors of

227


A

B Figure 10.38 (A) A 48-year-old male with a crush injury to the left foot with significant soft tissue defect, contamination, and calcaneal bone loss (B). Reconstruction options for this limb from a soft tissue and bone standpoint were limited and the patient elected to have a transtibial amputation. He returned to work 8 weeks after his surgery.

amputation . In addition , the data from this study revealed that lack of initial plan tar sensation on presentation after lower extrem ity traum a is not predictive of ultim ate return of n erve fun ction or clin ical outcom e. More th an on e-h alf of th e patien ts wh o presen ted with an in sen sate

foot th at was treated with lim b reconstruction ultim ately regain ed sen sation at 2 years. In itial plan tar sen sation was n ot progn ostic of lon g-term plan tar sen sory status or functional outcom es and should n ot be a compon ent of a lim b-salvage decision algorith m .

TABLE 10.4

MANGLED EXTREMITY SEVERITY SCORE Criteria

Description

Skeletal/soft tissue injury

Low energy (stab; simple fracture; pistol gunshot wound) Medium energy (open or multiple fractures, dislocation) High energy (high speed MVC or rifle GSI): Very high energy (high speed trauma + gross contamination):

1 2 3 4

Limb ischemia

Pulse reduced or absent but perfusion normal Pulseless; paresthesias, diminished capillary refill Cool, paralyzed, insensate, numb

1 2 3

Shock

Systolic BP always > 90 mmHg Hypotensive transiently

0 1

Persistent hypotension < 30 30–50 > 50

2 0 1 2

Age (years)

Score doubled for ischemia > 6 hours. MVC, motor vehicle collision; GSI, gunshot injury.

Points

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COMPLICATIONS ASSOCIATED WITH ORTHOPAEDIC TRAUMA Malunions Although the m ajority of fractures go on to union, they m ay heal in an unacceptable position th at causes significant im pairm en t. Th ere is n o gen eric defin ition of a m alun ion . Historically, each bon e h as been labeled “healed’’ within certain param eters. For example, acceptable healing after a tibia fracture is m ore th an 50% of cortical overlap, less than 10 degrees of angulation in any plane, less than 5 degrees of varus or valgus deform ity, less th an 10 degrees of an terior or posterior an gulation , less th an 10 degrees of rotation , an d less th an 1 cm of sh orten in g. Th ese param eters are n ot th e sam e for h um eral sh aft fractures. Th us, simply because a bon e h as h ealed in a n on an atom ic position does not necessarily m ean the fracture is m alun ited. In m alunion, the bone m ay be an gulated, m ay be rotated on itself, or th e fractured en ds m ay be overlapped causin g sh orten ing. Malun ion m ay be caused by in adequate im m obilization of th e fracture, m isalign m en t at th e tim e of im m obilization , prem ature rem oval of th e cast or oth er im m obilizer, or in complete or lim ited surgical fixation . A m alun ited fracture can lead to impairm en t, disability, degen erative join t disease due to altered biom ech an ics, an d referred pain (Fig. 10.39). Clin ically, m alun ion s are fractures th at h ave h ealed in a m an n er th at leads to eith er fun ction al an d/ or cosm etic deform ity. Man agem en t of m alun ion s, particularly with

deform ity correction , sh ould result in fun ction al im provem ent. Am alun ited articular injury (i.e., an articular fracture with step-off) can lead to early posttraum atic arth ritis particularly with weightbearing and range of m otion.

Nonunions Despite m eticulous care an d th e best of in ten tion s, fractures m ay not heal. An onunion is defin ed by the Food and Drug Adm in istration as a fracture that has not healed 9 m on ths after occurrin g, or a fracture that does not show progression of h ealin g in th ree con secutive radiograph s 1 m on th apart. Fractures typically do n ot h eal for four reason s: in fection , lack of blood supply, poor host factors, and biom echanical instability. In m ost clinical scenarios, it is com bination of these factors at play. One of the m ost important aspects of n on union care is diagn osin g th e etiology of th e n onunion as this will directly impact th e m anagem ent of the patient. Th e in itial m an agem en t of a n on un ion starts with the patien t’s index procedure. Optim izin g fracture care at the tim e of initial injury—through m eticulous soft tissue m anagem ent, lim itin g infection, and m axim izing stabilization —can go a lon g way in preven tin g th e developm en t of a n on un ion . Diagn osis of a n on un ion occurs th rough obtain in g an adequate history and physical exam ination and reviewing im aging studies. Critical elem ents of the history include tim e of injury, types of surgery, developm en t of infection, wh eth er th e fracture was open , an d fun ction al capacity.

Figure 10.39 (A) A 35-year-old firefighter who fell from

A

B

a ladder resulting in a distal third tibia fracture initially treated nonoperatively in a cast. Nine months later the patient was complaining of increasing difficulty walking, pain in the ankle, and a leg length discrepancy. (B) He underwent an osteotomy of his fibula and a take-down of his malunion with plate fixation to restore his length, alignment, and rotation.


Physical exam in ation sh ould focus on evaluation of th e skin an d soft tissue for surgical in cisions an d traum atic woun ds, pain at th e fracture site with direct palpation , sin us tracts, and instability. In addition to th e h istory an d physical exam in ation , im aging is essential in the diagnosis of a non union. Plain orth ogon al radiograph s are a critical first step in th e im aging of a poten tial n onunion. Obtaining additional oblique radiograph s h as been sh own to im prove th e sen sitivity an d specificity of detecting n onunions in long bones. Radiograph ic fin din gs supportin g n on un ion in clude an absen ce of bon e crossin g th e fracture site (bridgin g trabeculae), sclerotic fracture edges, persisten t fracture lin es, an d lack of evidence of progressive change toward union on serial radiograph s. Lack of callus is n ot a reliable radiologic param eter to use as callus would n ot be expected to be seen in patien ts un dergoin g prim ary bon e h ealin g (e.g., lag screw fixation with application of a n eutralization plate) but would be expected in patien ts with secon dary bon e h ealin g (e.g., IM n ail). Advan ced im agin g m odalities such as CT, MRI, an d tagged white blood cell scans m ay be used to provide additional inform ation regarding the con figuration of the nonunion or potential sites of in fection. Existing h ardware m ay preclude the ability to obtain quality im ages. Non un ion s can be classified by th eir appearan ce on radiograph s. Th e type of n on un ion , as depicted by th e

Figure 10.40 Hypertrophic nonunion of the humeral shaft. De-

spite callus formation, the humerus has not healed because of inadequate stabilization.

229

plain x-rays, can often h elp th e physician iden tify th e etiology of th e n on un ion . Hypertroph ic (or hyper-vascular) n on union s typically have a “h orse h oof’’ or “eleph an t foot’’ appearan ce, which represents abun dant callus as a result of a robust blood supply an d in adequate biom echanical stability (Fig. 10.40). A hypertrophic nonunion h as th e biologic buildin g blocks to h eal, but lacks the stability to complete th e process. Aside from exuberant callus on radiographs, patien ts m ay also exhibit increased uptake on radion ucleotide scan s, an d th is sh ould n ot be con fused with in fection . Man agem en t of hypertrophic n onunions typically involves stabilization of the n on union site through im m obilization or, m ore com m only, surgical stabilization with a nail or compression plate. At the opposite end of the spectrum , nonunions m ay be atrophic or avascular (Fig. 10.41). Radiographs show eburn ated, osteopen ic, an d/ or sclerotic bon e en ds. Th e n on union is biologically devoid of h ealin g an d, as such, th e en ds of th e bon e h ave becom e atroph ic an d osteoporotic. Because of th e lack of blood supply, a bon e scan will typically be cold represen tin g th e lack of biologic activity. Surgical m an agem en t in volves stabilization an d addition of biologically active m aterial (e.g., autograft, bon e m orphogenic protein ) to augm en t th e h ealin g respon se alon g with fixation.

Figure 10.41 Atrophic nonunion of the tibial shaft in an elderly

patient with diabetes, peripheral vascular disease, and poor nutrition. Despite surgical stabilization, there is no callus formation and the bone ends are sclerotic with little signs of vascularity.

230


A

B Figure 10.42 (A) Oligotrophic nonunion of the humeral shaft in a 42-year-old male who fell down the stairs. Despite several months of nonoperative management, the fracture showed no callus formation and no signs of healing. With surgical stabilization (B), the fracture healed 8 weeks later. No orthobiologic agents were necessary as the fracture ends were not necrotic.

O ligotroph ic n on un ion s do n ot sh ow callus on radiograph s but do n ot h ave sign s of sclerosis or bon e loss either (Fig. 10.42). Unlike atrophic n on unions, th e blood supply is typically intact an d a bone scan sh ows uptake. Th e h ealin g respon se is in adequate, an d th is m ay be due to excessively rigid fixation , distraction at th e fracture site, com m inution, or host factors such as poor system ic levels of vitam in D an d calcium . Recen t studies h ave exam in ed th e role of th e h ost in fracture healing revealing the importance of the endocrin e system . In the m anagem en t of n on un ions, som e surgeon s will obtain vitam in D, calcium , thyroid stim ulatin g h orm on e, protein, album in, m agnesium , and phosphorus levels in con jun ction with routin e blood work. Ph arm acologic correction of these important m arkers of healing in conjunction with appropriate m usculoskeletal interven tion h as been sh own to dram atically in crease n on un ion fracture healing rates. Lastly, infection h as been shown to delay or impede fracture healing. Infection typically occurs in the settin g of an open fracture but m ay also be a risk in patien ts with prolon ged surgical exposures, revision surgery, or m edical com orbidities. All patien ts wh o present with a nonunion, hardware failure, or delayed h ealin g, particularly with a history th at is con cern in g, sh ould un dergo a work-up for in fection as part of their nonunion evaluation. This work-up includes a complete blood cell count, erythrocyte sedim en -

tation rate (ESR), C-reactive protein (CRP). Im agin g m ay also be con sidered such as a tagged wh ite blood cell scan or a triple-ph ase bon e scan , as well as positron em ission tom ography. Lastly, som e surgeon s h ave advocated direct biopsy of th e n on un ion site with delayed m an agem en t un til form al biopsy results are available. Non e of th ese tests h as been sh own to have very high sensitivity or specificity, an d, as such , th e diagn osis of in fection con tin ues to be a com bination of clinical suspicion, im aging, history, and physical exam in ation . Managem en t of an infected n onunion is based upon th e wh ether the in fection needs to be eradicated or suppressed to obtain h ealin g. In th e presen ce of orth opaedic implan ts, it is extrem ely difficult to eradicate in fection . Iden tification of th e m icroorgan ism is critical to appropriate an tibiotic selection for eradication or suppression until healing in conjunction with debridem ent and rem oval of h ardware if n ecessary.

Osteomyelitis Postoperative wound in fections and osteomyelitis are usually related to h igh -energy in juries, which are associated with sign ifican t woun d con tam in ation an d osseous devascularization. Other risk factors include prolonged open woun d tim e, in adequate fixation , an d exten sive surgical dissection an d periosteal strippin g, wh ich com prom ise


blood flow to th e woun d. Patien ts can presen t with a myriad of signs and symptom s including pain , tenderness, fever, headach e, nausea, vom iting, erythem a, swelling, sinus tracts, drainage, and fluctuance. Laboratory data can aid in the diagnosis of osteomyelitis. In acute osteomyelitis, the white blood cell coun t is elevated on ly 25% of th e tim e an d sh ows an abn orm al differen tial on ly 65% of th e tim e. Blood cultures in acute osteomyelitis are positive on ly 50% of th e tim e. Ch ron ic osteomyelitis often sh ows a m ild an em ia with elevation s of ESR an d CRP. Th ere m ay be a leukocytosis with a left sh it, but th is is n eith er specific n or sen sitive. Blood cultures are alm ost always negative. Various im aging m odalities can be utilized to help determ ine the presence and breadth of in fection. Radiographs are positive in 90% of cases by 3 to 4 weeks after inoculation. The earliest bone changes are those of destruction or resorption , usually seen as m ottled areas of decreased den sity in m etaphyseal areas. Over tim e, a th in lin e of newly form ed bon e parallel to the sh aft m ay be detected in the periosteal regions of the m etaphysis as new bone results from in fection progressin g in to th e subperiosteal region an d gradually exten din g alon g th e sh aft. If th e in fection is not controlled, th e new periosteal bone thicken s over succeedin g few weeks becom es an in volucrum . After several weeks have passed an d the disease is in ch ron ic ph ase, sequestra m ay appear as opaque areas of bon e, usually surrounded by radiolucen t zone consisting of exudate an d granulation tissue. Occasionally, an acute m etaphyseal osteomyelitis is con tain ed locally by th e h ost defen ses. In such instan ces, the infection becom es surroun ded by scar tissue and a rim of reactive bon e, resulting cavity or cyst is filled with pus, which m ay ultim ately becom e sterile. A bon e abscess resultin g from th is localized form of th e disease is called a Brodie’s abscess. An MRI m ay h elp iden tify associated abscesses, sequestra, and sin us tracts and m ay also reveal specific changes in bone m arrow. In bon e m arrow, inflam m atory exudate has decreased signal on T1 as compared with norm al m arrow. Infected m arrow will have higher signal on T2. A triple phase bone scan, often perform ed with eith er tech n etium 99m or in dium 111, is positive 3 to 4 days after in fection . Th e th ree ph ases of the bon e scan involve a radionucleotide angiogram , im m ediate postinjection blood pooling, and ultim ately decreased soft tissue presence with increased urinary excretion. Osteomyelitis shows increases in phases one and two, an d focal increases in the third phase at the 3-hour tim e poin t. An anatom ic classification system for osteomyelitis has been provided by Drs Cierny an d Mader (Fig. 10.43). Th e location of the osteomyelitis can be completely m edullary (type I), superficial with a sinus tract from the skin extending down to the cortex (type II), localized where the cortex is violated, but the infection is contained (type III), an d diffuse wh ere th e in fection h as eroded th rough each cortex (type IV). In addition to classifyin g th e location of th e osteomyelitis an d its im pact on th e bon e, Drs Cierny an d

Medullary

Superficial

Localized

Diffuse

231

Figure 10.43 Anatomic classification of osteomyelitis based on the involvement of the soft tissue and location in the bone.

Mader also classified the host (patient). Type A hosts h ave a good im m un e system an d delivery of an tibiotics an d n utrition to th e infection site. Type B hosts are comprom ised eith er locally (type BL), system ically (type BS), or both (BC ). Type C h osts are patien ts wh o require suppressive th erapy on ly or wh o h ave m in im al disability wh ere th e treatm ent would result in greater m orbidity th an th e in fection itself. Th ese patien ts are often n ot surgical can didates. Th e prim ary treatm en t for osteomyelitis is prevention. On ce a patient has osteomyelitis, the prim ary goal is identifyin g th e correct organ ism an d eradicatin g th e in fection. Staphylococcus aureus is th e m ost com m on offending organism (90% of cases). Treatm ent for osteomyelitis consists of incision al drain age, debridem ent and irrigation, followed by in travenous antibiotics. Temporary implantation of an tibiotic-im pregn ated cem en t beads an d hyperbaric oxygen can h elp with m ore resistan t cases. Osseous an d soft tissue stability is essen tial with appropriate soft tissue coverage (Fig. 10.44).

Septic Arthritis Patien ts with a distan t focus of in fection can presen t with n ew onset joint pain because of h em atogen ous spread of a bacterial organ ism with in th e con fin es of a join t capsule (i.e., syn ovial join t). The classic clinical scenario is a patien t with pn eum on ia or bacterial en docarditis that presen ts with n ew on set h ip pain . In th e im m un ocompeten t patien t, th e body’s reaction to in tra-articular in fection is to m ount a sign ifican t inflam m atory response with the

232


A,B

C

D,E

F Figure 10.44 (A) Lateral radiograph of a 39-year-old male 18 months after operative stabilization of an open tibia fracture showing an atrophic nonunion. (B) Physical examination revealed a draining sinus tract directly over the nonunion site near the open fracture. The patient was taken to the operating room for debridement of his sinus tract and osteomyelitis (C) and placement of an antibiotic spacer and antibiotic nail (D). He also had a free flap performed to cover the defect (E). After 6 weeks of intravenous antibiotics, he was taken to the operating room for repair of his nonunion with bone grafting and intramedullary nailing. Six months later, he united his fracture (F) with no signs of recurrence of infection and intact soft tissue.

deposition of several cytokin es, elastases, proteases, an d oth er en zym es, wh ich will lead to th e even tual destruction of articular cartilage. Septic arth ritis is a surgical em ergen cy an d in volved join ts sh ould be irrigated an d debrided as soon as possible. The clin ical exam ination m ay be equivocal in im m un ocomprom ised patien ts (e.g., diabetics, posttransplan t, patien ts on ch em oth erapy, HIV positive, an d in traven ous

drug abusers). Th e path ogn om on ic physical exam in ation finding is m icrom otion pain with attempted joint ran ge of m otion. Patients with a septic joint often sit in a position to m axim ize the intracapsular volum e so as to m inim ize th e degree of stretch on th e join t capsule an d th us reduce pain . Im m un ocom prom ised patien ts as well as diabetics with periph eral n europathy m ay presen t with a septic join t with out m uch pain . O n e of th e few clin ical clues to aid


in the diagnosis m ay be overlying cellulitis in conjunction with a h istory th at raises th e in dex of suspicion . Diagn osis of a septic join t is based on a sterile aspirate of the intra-articular fluid, which is sent to the laboratory for wh ite blood cell coun t, gram stain , an d culture an d sen sitivity. In addition, the aspirate fluid should also be assessed for gouty crystals, which could result in a sim ilar clinical picture. In aspiratin g a join t, it is im perative n ot to m ake th e portal of en try th rough overlyin g cellulitic skin in an effort to avoid seedin g th e join t with bacteria from th e skin in fection . In addition, th e system ic white blood cell coun t as well as th e ESR an d CRP m ay provide furth er in form ation . Th e ESR an d CRP m ay be elevated in th e acute ph ase. Even if convincing evidence is presen t to m ake the diagnosis, it is important to not adm inister intravenous antibiotics until after sterile cultures are taken in the operating room at the tim e of defin itive treatm ent. When evaluatin g th e cell coun t, a septic join t is defined as any joint with m ore than 50,000 white blood cells with greater th an 85% to 90% polym orph on uclear cells. Cell coun ts of less than 50,000 m ay signify inflam m atory disorders or crystallin e disease an d m ay warran t sen din g th e fluid to the laboratory for crystal analysis (i.e., gout or calcium pyrophosphate disease—pseudogout). Th e surgical treatm en t of septic arth ritis is th orough irrigation and debridem ent. The involved join t can be irrigated usin g eith er an open tech n ique or an arth roscopic tech nique, based on equipm ent availability. In th e operatin g room , it is imperative to obtain sterile cultures before th e adm inistration of antibiotics. After cultures have been sent to th e laboratory, a th ird-gen eration ceph alosporin such as cefazolin is given to cover the m ost com m on offending organ ism , S. aureus. A large drain m ay be left in th e join t to allow for egress of any addition al purulen t collection s with in th e join t. Patien ts m ay require repeat irrigation an d debridem en t with in 48 to 72 h ours to decrease th e burden of in flam m atory in tra-articular m ediators. Th e postoperative regim en warrants the placem ent of a peripheral intravenous central catheter for 6 weeks of organism -specific an tibiotic therapy. Following successful treatm ent of septic arthritis, the goal is to regain range of m otion and function of th e join t/ extrem ity.

Necrotizing Fasciitis Necrotizin g fasciitis is defin ed as an in fection of th e subcutaneous tissue overlying th e fascia of an extrem ity. Th e m ost com m on organism in volved in this type of infection is group A streptococcus. Patients typically present with a superficial skin infection that looks innocuous. However, the incitin g physical exam ination finding is pain out of proportion to th e clin ical exam in ation . Cellulitis is a superficial in fection of th e epiderm is an d m ay present in sim ilar fash ion to necrotizing fasciitis. However, n ecrotizin g fasciitis is often associated with an ele-

233

vated body tem perature an d h em odyn am ic in stability (hypoten sion ). In th e early stages, h em odyn am ic in stability m ay be absen t an d by th e tim e hypoten sion is presen t, th e in fection m ay h ave becom e m ore exten sive. A m issed diagn osis of necrotizin g fasciitis is fatal. Any patien t with th e diagn osis of n ecrotizin g fasciitis requires em ergen t surgical debridem en t of th e affected region . An exten sile exposure is utilized to expose from th e level of th e skin to th e un derlyin g deep fascia. Th e in fection h as been described as “dish water’’ pus an d requires th orough irrigation an d debridem en t. Hypoten sive patien ts require close ICU care in th e im m ediate postoperative period to optim ize th eir h em odyn am ic status. Repeat irrigation an d debridem en t is th e stan dard of care an d allows for exploration of th e woun d for evaluation of in fection spread. In travenous antibiotics are th e m ain stay of treatm ent and duration is typically 6 weeks.

SUMMARY Th e m an agem en t of th e orth opaedic traum a patien t is a m ultidisciplinary effort. Th e orthopaedic surgeon is critical in th is evaluation, which includes an adequate history, thorough physical exam ination, and directed im aging tech n iques. Ath orough un derstan din g of com m on m usculoskeletal conditions is necessary. On ce the injuries have been defin ed, a plan is design ed to m an age th e patien t’s injuries addressing life-threaten ing fractures initially with con trol of bleedin g an d tem porizin g stabilization . Great care is taken to preven t th e “second h it.’’Preoperative plann in g is essen tial in the m an agem en t of diaphyseal and articular injuries. Particular attention needs to be paid to the preven tion of com plication s in th is often ch allen gin g patient population.

RECOMMENDED READINGS Bh an dari M, Guyatt G, Torn etta P III, et al. Ran dom ized trial of ream ed an d unream ed intram edullary nailin g of tibial sh aft fractures. J Bone Joint Surg Am. 2008;90(12):2567 –2578. Bosse MJ, MacKen zie EJ, Kellam JF, et al. An an alysis of outcom es of reconstruction or am putation after leg-threatening injuries. N Engl J Med. 2002;347(24):1924 –1931. Garden RS. Stability and union in subcapital fractures of the fem ur. J Bone Joint Surg. 1964;46B(4):630 –647. Gustilo RB, An derson JT. Prevention of infection in th e treatm ent of one thousand and twen ty-five open fractures of long bon es: retrospective and prospective analyses. J Bone Joint Surg Am. 1976;58: 453 –458. Letourn el E. Acetabulum fractures: classification an d m an agem en t. Clin Orthop Rel Res. 1980;151:81 –106. Routt ML, Nork SE, Mills WJ. High en ergy pelvic rin g disruption s. Ortho Clin North Am. 2002;33(1):59 –72. Siebel R, LaDuca J, Hassett JM, et al. Blun t m ultiple traum a (ISS 36), fem ur traction , an d th e pulm onary failure-septic state. Ann Surg. 1985;202(3):283 –293. Win quist RA, Han sen ST, Clawson DK. Closed in tram edullary n ailin g of fem oral fractures. A report of five hundred and twen ty cases. J Bone Joint Surg Am. 1984;66:529 –539.

11

Pediatric Orthopaedics Sectio n 1

General and Regio nal Pro blems in Children Wudbhav N. Sank ar

Ch ildren are very different from adults. Youth is a tim e of rapid growth , m usculoskeletal developm en t, an d em otional m aturation. The unique physiology of children m akes them susceptible to very different orth opaedic condition s compared with adults. In addition , m ost m etabolic an d congenital disorders present at an early age. Proper care of pediatric patien ts rests upon a proper un derstan din g of norm al growth an d developm ent; global n eurom uscular, m etabolic, and hereditary conditions; and several specific region al issues.

TORSIONAL AND ANGULAR VARIATIONS Before one can diagnose an d effectively treat diseases of the pediatric m usculoskeletal system , one m ust understan d wh at constitutes n orm al growth and developm en t. Torsional and angular chan ges in the lower extrem ity are am ong the m ost com m on reasons for referral of a ch ild. Th e complain t of in -toein g or out-toein g as well as kn ockknees an d bow-legs are a m ajor preoccupation of parents an d gran dparents alike. In spite of these concerns, the vast m ajority of th ese children are n orm al ch ildren wh o are simply reflecting m odest variations in growth an d developm en t. Th e physician evaluatin g a ch ild with a torsion al or an gular variation sh ould carefully assess th e patien t to be sure th at th ere is n o un derlyin g path ologic con dition before reassurin g th e fam ily th at th e fin din gs are in deed norm al variations.

Physiology Variations in axial rotational align m ent are usually due to m echanical forces applied in utero. Inside the wom b, the

Karen Myun g

Robert M. Kay

fetus can assum e a position in which the feet are tucked in ward, th e tibiae are in tern ally twisted, an d th e h ips are m edially rotated. Th ese forces result in variable am oun ts of m etatarsus adductus, in tern al tibial torsion , an d fem oral an teversion at birth . With n orm al growth , h owever, each of th ese th ree con dition s will, to a large exten t, rem odel. For exam ple, fem oral an teversion is typically 30 to 40 degrees at birth but even tually decreases to an adult an gle of 10 to 15 degrees. Fron tal plan e an gulation s such as kn ockkn ees and bow-legs also follow a predictable course. Most n eon ates will dem on strate som e am oun t of gen u varum at birth due to in trauterin e position in g an d extern al rotation con tractures of th e h ip. Before th e walkin g age, gen u varum m ay actually h elp a ch ild clin g to a paren t’s h ip. Th is varus pattern persists th rough th e first year of life with n orm alization to a neutral axis around 18 m onths of age. Most ch ildren actually develop in creased gen u valgum begin n in g at age 2. Maxim um kn ock-kn ee is usually presen t in th e 2- to 4-year-old age group with rapid spontaneous correction th ereafter, with essen tially adult align m en t ach ieved by 6 to 7 years of age (Fig. 11.1).

Presentation Paren ts of in -toein g ch ildren typically com plain of th e cosm etic appearance, frequent trippin g, or an awkward “eggbeater’’ run n in g style. Th e cause of in -toein g can often be deduced sim ply by th e age at wh ich th e ch ild presen ts. Children who are just beginning to walk typically have residual m etatarsus adductus from in trauterin e position ing. Between ages 1 and 3, internal tibial torsion is the m ost likely culprit (Fig. 11.2). After age 3, the m ost likely cause of in -toein g is persisten t fem oral an teversion th at h as yet to rem odel. Out-toeing is a less com m on presentation and is also of no functional con sequen ce.

236


Figure 11.1 (A) A 6-month-old

A 6 mo

B 18 mo

C 4 yr

Ch ildren with an gular variation s presen t accordin g to their norm al developm ental sequence. Parents of toddlers typically com plain of a “bow-legged’’ appearan ce wh ile presch ool ch ildren usually presen t with “kn ock-kn ees’’ (Fig. 11.3). These physiologic variations are not symptom atic but m ay cause an xiety for th e paren ts due to th e cosm etic appearan ce. The m ost com m on angular com plain t in adolescen ts is persisten t gen u valgum , wh ich m ay

D Young adult

child with genu varum. (B) An 18month-old child with straight legs. At some point in most children, usually around 18 months of age, the legs are perfectly straight as their developmental stage passes from genu varum to genu valgum. (C) A 4-year-old child with genu valgum. (D) Adults normally have a mild amount of genu valgum. (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

cause their knees to rub togeth er when they run or play sports.

History and Physical Examination Although m ost torsional and angular variation s are physiologic, it is important to take an accurate history to screen for an un derlying abnorm ality. Abirth history should be taken

Figure 11.2 Internal tibial torsion is often

A

B

seen in toddlers with an in-toed gait. (Reprinted with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Chapter 11: Pediatric Orthopaedics

237

Thigh-foot angle TFA

40°

2SD 20° 0 2SD −20° −40° 1

3

5

7

9

11 13 15–19 30s 50s 70+

Age (yr)

Figure 11.5 Normative values for thigh–foot angle. The solid

line demonstrates mean values and the shaded area represents ± 2 standard deviations. (Reprinted with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Figure 11.3 Genu varum in a toddler. (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

an d gross m otor m ilestones should be assessed, in cluding the age at which th e child first walked. Patients who are not growin g appropriately m ay h ave a skeletal dysplasia or an un derlyin g syn drom e. Th e overall effect of torsion al variation s on a ch ild’s walkin g can be assessed by m easuring the foot-progression an gle. Norm ally, when a child walks, the foot should be sligh tly externally rotated from the line of progression by approxim ately 10 to 15 degrees. In-toeing is diagn osed if the foot progression angle is negative, and out-toeing refers to extern al rotation of th e foot beyon d 25 degrees (Fig. 11.4). The physical exam ination of a child with an abnorm al foot progression angle focuses on each level of the

Foot progression angle FPA 20°

2SD

10°

0

−10°

2SD

1

3

5

7

9

11 13 15–19 30s 50s 70+

Age (yr)

Figure 11.4 Normative values for foot progression angle. The

solid line demonstrates mean values and the shaded area represents ± 2 standard deviations. (Reprinted with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

lower extrem ity to develop a torsion al profile. Th e feet are evaluated first to look for abn orm alities such as m etatarsus adductus. Tibial rotation can be quan tified by m easurin g th e th igh –foot angle (Fig. 11.5). With the child is lying prone and th e knee is flexed at 90 degrees, the angle between the thigh and the long axis of the foot can be assessed. After age 8, th e th igh –foot angle averages 10 degrees extern al (ran ge 0 –20 degrees). Measurem ents below th is ran ge in dicate in tern al tibial torsion an d values greater th an 20 degrees in dicate extern al tibial torsion . Drawbacks of th is m easurem en t are its sen sitivity to th e position of th e foot and lack of reliability in cases of coexisting foot deform ity. Alternatively, th e transm alleolar axis can be m easured. Th is is the an gle form ed between an im aginary line drawn th rough th e fem oral con dyles an d an im agin ary lin e drawn th rough th e m edial an d lateral m alleoli. Values less th an 10 degrees im ply in tern al tibial torsion an d m easurem ents greater th an 30 degrees indicate external tibial torsion . Fem oral version is best evaluated by m easuring h ip rotation in th e pron e position with th e h ips exten ded an d th e kn ees flexed 90 degrees (Fig. 11.6). By age 10, in tern al hip rotation averages 50 degrees (ran ge 25 –65 degrees) and external rotation 45 degrees (range 25 –65 degrees). In tern al h ip rotation greater th an 70 degrees implies in creased fem oral an teversion . Likewise, dim in ish ed in tern al rotation is seen in ch ildren with fem oral retroversion . Angular variations can be quantified by m easuring the interm alleolar distan ce (for genu valgum or knock-knees) or th e in tercon dylar distan ce (for gen u varum or bow-legs). Th ese m easurem en ts provide an objective m easure th at paren ts an d physician s can follow as th e ch ild grows. Up to 12 degrees of gen u valgum an d an in term alleolar distan ce of 8 cm is within the norm al range (Fig. 11.7). Intercon dylar distan ce sh ould decrease by age 2. Exam in ers sh ould be careful n ot to con fuse apparen t gen u varum due to tibial torsion with a true bow-legged appearance. To rem ove the optical illusion caused by th e kn ees poin tin g laterally, th e legs should be rotated until the patellas poin t an teriorly (Fig. 11.8).

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Medial rotation

Medial rotation

MR girls

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Figure 11.6 Normative values for (A and B) in-

ternal and (C) external hip rotation that can be used to judge femoral version. The solid line demonstrates mean values and the shaded area represents ± 2 standard deviations. (Reprinted with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

N =196

A

Figure 11.7 Mean values and standard

B

deviations for (A) knee angle and (B) intercondylar or intermalleolar distance. (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)


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Figure 11.8 (A) Child demonstrating the apparent

genu varum of tibial torsion. The chief complaint of this child’s parents was bowed legs. With the feet pointing forward, the legs have the appearance of genu varum when the child is supine or walking. The apparent “bowing” is a product of the knees pointing laterally, so knee flexion gives the appearance of bowing. (B) When the child’s patellas point anteriorly, it is clear that there is not significant genu varum present. (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

A

Radiographs Although plain radiograph s h ave lim ited utility in the evaluation of torsion al variation s, stan din g full-len gth radiograph s can be very useful for workin g up m oderate to severe an gular variations (Fig. 11.9). Usin g this radiograph, the an atom ic axis between the fem ur and the tibia can be m easured to quantify the degree of knock-knees or bow-legs.

B

In addition , on e can evaluate th e ch ild’s weigh t-bearin g axis, which is the line intersecting th e center of the fem oral h ead an d th e cen ter of th e an kle. Norm ally, th is axis runs th rough approxim ately th e cen ter of th e kn ee join t. With increasing genu varum , the weigh t-bearing axis falls m ore m edially. Sim ilarly, increased genu valgum causes the axis to fall lateral to the cen ter of the knee.

Special Studies Advan ced im agin g is rarely n ecessary in th e evaluation of torsional or angular variation s. Occasion ally, severe cases of fem oral an teversion or retroversion m ay warran t a com puted tom ography (CT) to quan tify th e exact degree of rotation al deform ity.

Differential Diagnosis

Figure 11.9 Physiologic genu varum in a toddler. Note that the weight-bearing axis falls medial to the knee joint.

Alth ough th e vast m ajority of torsion al an d an gular variations are physiologic an d will improve with age, it is importan t to rule out an un derlyin g path ologic con dition before reassurin g th e fam ily th at th eir ch ild is n orm al. Torsion al variations m ay cause tripping but should not cause a limp n or should it be pain ful. Existen ce of eith er of these two sym ptom s should prom pt a workup for oth er causes. Unilateral in -toeing can be due to hem iplegic cerebral palsy (CP) or other neurom uscular condition. Out-toeing in an older ch ild can be caused by a slipped capital fem oral epiphysis (SCFE) or coxa vara. Angular variations outside the range of norm al can be caused by a n um ber of differen t con dition s, m ost of wh ich are described in detail elsewhere in this chapter. In evaluating a toddler with bowed legs, the m ost importan t diagn osis to consider is Bloun t disease (tibia vara). In particular, Bloun t disease sh ould be suspected wh en th e ch ild is older th an 2 years, th e varus deform ity is sh arply an gular, a lateral kn ee th rust is presen t with am bulation , th e bowin g

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A

B Figure 11.10 Anteroposterior radiographs (A) 4 weeks after and (B) 8 weeks after tibial rotational osteotomy. In this case, pins and a cast were used to achieve fixation at the osteotomy site. (Reproduced with permission from Skaggs DL, Tolo VT. Master Techniques in Orthopaedic Surgery: Pediatrics. Philadelphia, PA: Lippincott Williams & Wilkins, 2008.)

is particularly severe, an d ch aracteristic radiograph ic ch an ges are seen in th e proxim al tibia. Rickets an d skeletal dysplasias can presen t with eith er gen u varum or gen u valgum . Usually, th ese ch ildren h ave sm all stature an d typical radiographic fin dings. Other potential causes of angular deform ity in clude ren al osteodystrophy, con gen ital pseudarth rosis of th e tibia (CPT), traum a to th e physis, an d in fection .

Treatment Torsion al variation s rarely require form al treatm en t. Although th e presence of in-toeing or out-toeing m ay frustrate paren ts, th e vast m ajority of th ese con dition s improve spontaneously with age. Th ere is no evidence th at bracin g or special sh oes h elp accelerate th e n atural h istory. O n rare occasions, children with torsional deform ities that persist in to adolescence and cause fun ctional problem s can be treated with corrective osteotomy of th e tibia or fem ur (Fig. 11.10). Physiologic an gular variation s sh ould also be observed for spontan eous improvem ent. Of course, all ch ildren with an un derlyin g etiology sh ould be treated for th eir diagn osis. Occasion ally, ch ildren will present with persisten t m oderate to severe gen u valgum in th eir early teen age years. O perative treatm en t can be con sidered for th ose adoles-

cen ts wh o are symptom atic from pain or gait disturban ce and for those with a weight-bearing axis th at passes lateral to the knee. Prior to skeletal m aturity, treatm ent usually con sists of tem porary h em iepiphysiodesis of th e distal fem ur an d/or proxim al tibia, using staples or “8’’plates (Fig. 11.11). After skeletal m aturity, corrective osteotom y m ay be n ecessary.

NEUROMUSCULAR DISEASE Ch ildren afflicted with n eurom uscular diseases frequently m anifest severe m usculoskeletal abnorm alities. Not only do th ey suffer from th e in trin sic effects of th e n europath ic or myopath ic abn orm alities but th ey are usually profoun dly affected by th e secon dary bon e an d join t deform ities that result from these diseases. For m anagem ent to be effective, it is importan t th at th e physician recogn ize the basic differences between the neurom uscular disorders. Certain neurologic diseases are cen tral, whereas others are periph eral; som e affect on ly th e m otor system , wh ereas oth ers affect both sen sory an d m otor compon en ts. CP, for exam ple, is a cen tral n eurologic con dition with resultin g spasticity in th e periph ery. Children with CP typically have reason able sen sation . In con trast, myelodysplasia affects the spinal cord and adjacent nerve roots, leavin g little m otor


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less th an 1,500 g h ave a 25 tim es in creased risk of developin g CP. Fin ally, h ead traum a, in traven tricular h em orrh age, an d m en in gitis are examples of postn atal causes of CP.

A

B

Figure 11.11 (A) This teenaged girl did not like the appearance

of her genu valgum and complained that her knees rubbed together when she played sports. (B) Repeat standing radiograph after temporary hemiepiphysiodesis of the distal femur using “8” plates. (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, CA.)

or sen sory fun ction below th e lesion . Muscular dystroph ies (Duchenne and oth ers) affect the end organ, causing significant myopathic chan ges. Nerves, h owever, are typically un affected. Arth rogryposis is a n eurom uscular disease of un kn own etiology. Typically, m uscles are poorly developed but n erve fun ction exists.

Cerebral Palsy Pathophysiology CP is really not one disease but rath er a syndrom e of m otor disorders th at result from an in sult to th e im m ature brain . Th e size an d scope of th e brain in jury affects n ot on ly th e severity of m otor in volvem ent but also the child’s speech , cognition , an d overall functional ability. CP is the m ost com m on neurom uscular disorder in children an d is characterized by a static, nonprogressive central injury. As a consequen ce, the usual inh ibitory role of the cen tral nervous system (CNS) is suppressed, resulting in increased periph eral spasticity. Over tim e, th is spasticity results in con tractures and joint deform ities. Pren atal causes in clude infections such as toxoplasm osis, rubella, cytom egalovirus, herpes, an d syph ilis, as well as m atern al drug an d alcoh ol use. Perin atal causes include birth traum a and an oxia. In fact, prem aturity is th e m ost com m on risk factor for CP. In fan ts

Classification CP can be classified physiologically, geographically, or function ally. Physiologic grouping is based on th e location of the brain lesion an d the m ovem ent disorder that results. Spastic CP, th e m ost com m on form of CP, occurs wh en th e pyram idal tracts of th e brain are affected. Dyskin esia, ch aracterized by ath etosis, ch orea, an d oth er in volun tary m otor m ovem en ts, occurs wh en th e extrapyram idal region s becom e in jured. Som e ch ildren m ay h ave a m ixed picture, with both pyram idal an d extrapyram idal features. Geograph ic classification is based on th e distribution of lim bs th at are affected. Hemiplegia refers to arm an d leg involvem ent on one side of the body, diplegia describes prim arily bilateral lower extrem ity involvem ent, an d quadriplegia affects all four extrem ities. Significant overlap can occur between th e geograph ic classification s; for example, severe diplegia can often be confused with m ild quadriplegia depen din g on th e exten t of upper extrem ity involvem ent. As a result, m any physicians prefer a Gross Motor Function Classification System (GMFCS), wh ich is based on th e ch ild’s level of am bulation an d use of assistive devices (Fig. 11.12). Presentation CP can present in m any different ways. Com m on reasons for referral include limping, leg-length discrepancies, foot problem s, toe-walkin g, tigh t m uscles, an d/ or poor upper extrem ity fun ction . Typically, gross m otor developm en t is delayed; however, th is depen ds on the severity of central injury. In addition, in telligence and com m unication skills vary depen ding on the degree of in volvem en t. Hem iplegic ch ildren often h ave n orm al in telligen ce, wh ereas som e quadriplegic children dem on strate significant m ental deficits an d an in ability to com m un icate in a m ean in gful m anner. History and Physical Examination Most ch ildren with CP have a history of prem aturity, prolonged delivery, and/ or anoxic injury about the tim e of birth . A detailed birth h istory sh ould also in clude problem s during pregnancy and the duration of hospitalization after birth. A careful developm ental history m ay reveal eviden ce of developm en tal delay. On average, ch ildren sh ould sit by 6 m onth s, stan d by 8 m onths, and walk by 12 m onths. If a ch ild does n ot reach th ese m ileston es by 1.5 tim es th ese ages (i.e., sit by 9 m onths, stan d by 12 m onths, or walk by 18 m on th s), an in vestigation in to the developm ental delay is warranted. Another useful h istorical detail is early handedn ess. A preferen ce for a certain h an d prior to 1 year of age m ay be a sign of hem iplegia. Physical exam in ation sh ould in clude ran ge of m otion of all joints along with an assessm en t of m uscle tone, selective m otor control, an d upper and lower extrem ity reflexes.

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Figure 11.12 The Gross Motor

Function Classification system (GMFCS). GMFCS level 1: Children walk indoors and outdoors and climb stairs without limitation. Children perform gross motor skills including running and jumping, but speed, balance, and coordination are impaired. GMFCS level II: Children walk indoors and outdoors and climb stairs holding onto a railing but experience limitations walking on uneven surfaces and inclines and walking in crowds or confined spaces. Children have, at best, only minimal ability to perform gross motor skills such as running and jumping. GMFCS level III: Children walk indoors or outdoors on a level surface with an assistive mobility device. Children may climb stairs holding onto a railing. Children may propel a wheelchair manually or are transported when traveling for long distances or outdoors on uneven terrain. GMFCS level IV: Children may continue to walk for short distances on a walker or rely more on wheeled mobility at home and school and in the community. Children may achieve self-mobility by using a power wheelchair. GMFCS level V: Physical impairments restrict voluntary control of movement and the ability to maintain antigravity head and trunk postures. All areas of motor function are limited. Children have no means of independent mobility and are transported. (Redrawn with permission from Graham HK. On the other hand: classifying cerebral palsy. J Pediatr Orthop. 2005;25(1):127.)

Typically, ton e an d reflexes are in creased, wh ereas selective m otor con trol is decreased. In particular, fun ction at th e an kle, knee, and h ip should be carefully evaluated. An kle dorsiflexion sh ould be m easured carefully with the h indfoot in verted to lock th e subtalar join t an d with th e kn ee both flexed and exten ded to differentiate the contribution of th e gastrocn em ius (wh ich crosses both join ts) to th e overall tigh tn ess of th e Ach illes ten don (Fig. 11.13). Ham strin g tigh tn ess can be assessed by m easurin g th e popliteal an gle (th e an gle form ed between th e vertical an d th e leg) with th e hip flexed 90 degrees and the contralateral hip an d kn ee exten ded (Fig. 11.14). Adductor tigh tn ess is m easured by th e degree of abduction of th e leg, with th e h ip an d kn ee exten ded. Fixed join t con tractures sh ould also be evaluated as both h ip an d kn ee flexion con tractures are com m on . To accurately m easure a hip flexion contracture, the con tralateral hip should be flexed to flatten the lum bar an d stabilize

th e pelvis (Fig. 11.15). Wh en both h ips are flexed an d brough t togeth er in th e m idlin e, a kn ee h eigh t differen ce is a “positive” Galleazi test an d is suggestive of h ip subluxation or dislocation on th e shorter side. In quadriplegic children, the spine should be evaluated for scoliosis an d the child’s overall sittin g balance an d pelvic obliquity should be assessed. Perh aps th e m ost im portan t compon en t of th e physical exam in ation in am bulatory ch ildren is watch in g th e ch ild walk. Evaluation of gait is th e best fun ction al assessm en t of th e ch ild. During gait, torsional abnorm alities and dyn am ic issues can be diagnosed, an d on e can assess th e overall effect of th e static con tractures an d m uscle tigh tn ess on function.

Radiographs Th e m ost importan t radiograph in a ch ild with CP is an an teroposterior (AP) view of the pelvis. Persistent


A

243

B Figure 11.13 (A) Dorsiflexion should be measured in both with the knee extended (A) and the

knee flexed 90 degrees (B). The latter technique relaxes the gastrocnemius muscle. By comparing the range of motion in both positions, one can assess the contribution of the gastrocnemius to the overall tightness of the Achilles tendon. (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, CA.)

hyperton icity aroun d th e h ips can lead to “spastic h ip disease’’ or progressive subluxation an d dislocation of th e hip due to overpull of the adductor and iliopsoas m uscles. These hips are initially norm al at birth , so it is importan t to m on itor th em radiograph ically over tim e to iden tify those hips that are “at risk’’for subluxation. The m ost com m on ly used radiographic index for quantifying the severity of spastic h ip disease is th e Reim er m igration percen tage (or m igration index). The m igration percentage is calculated by dividing the width of th e uncovered fem oral head

Figure 11.14 Hamstring tightness can be assessed by mea-

suring the popliteal angle. This is the angle formed between the vertical and the child’s leg when the hip is flexed to 90 degrees. (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, CA.)

( A) by the total width of the fem oral head ( B) (Fig. 11.16). In dices greater th an 25% m ay in dicate th e n eed for soft tissue surgery, whereas percentages greater than 50% probably require bony reconstruction.

Special Studies In recen t years, quan titative gait evaluation usin g th reedim en sion al com puterized m otion an alysis h as becom e increasingly popular to help plan appropriate surgical intervention. These studies are perform ed at specific gait laboratories an d can be extrem ely useful for system atically evaluatin g th e com plex walkin g pattern s of patien ts with CP.

Figure 11.15 Hip flexion contracture is best assessed by using

the Thomas test. The contralateral hip is flexed to flatten the lumbar spine and stabilize the pelvis. The residual flexion of the hip compared to the horizontal is the amount of hip flexion contracture that is present. (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, CA.)

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in th e lower extrem ity affect the alignm ent and function at other levels. Failure to address the various problem s sim ultaneously results in suboptim al treatm ent outcom es. Curren tly, single-event m ultilevel surgery (SEMLS) is the preferred treatm en t because it allows for sim ultan eous correction of m ultiple deform ities, th us providin g for optim al correction of th e deform ities wh ile lim itin g th e ch ild to a sin gle recuperative period.

Treatment of Regional Deformities

Figure 11.16 The migration index is calculated by dividing the

width of the uncovered femoral head (A) by the total width of the femoral head (B). (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, CA.)

General Treatment Principles Th e m an agem en t of CP is complex an d is best accom plish ed as a team effort. Developm en tal pediatrician s, neurologists, physical therapists, and orthotists all m ust participate in th e overall decision -m akin g process. Medical spasticity m anagem ent m ay in clude oral m uscle relaxan ts such as diazepam and baclofen. In severely involved patien ts, baclofen can be given in trath ecally, wh ere it h as th e advan tage of m ore direct targetin g, wh ich allows for lower doses an d less system ic CNSdepression . Appropriate physical therapy and bracin g can be extrem ely useful to m aintain flexibility and delay the need for surgery. Botulinum toxin, a n eurotoxin from Clostridium botulinum, preven ts acetylch olin e release at th e n eurom uscular jun ction . Alth ough the effects last only for 3 to 6 m onths, the injections can be a useful adjun ct to th erapy and casting as a m eans to control periph eral spasticity. Selective dorsal rh izotom y, th e cuttin g of certain dorsal spin al rootlets, is a neurosurgical procedure that can help in spasticity m anagem ent. The ideal can didate is a youn g diplegic ch ild with good selective m otor con trol an d am bulatory poten tial. From a m usculoskeletal stan dpoin t, th e spasticity associated with CP can affect m ultiple joints and m ay cause deform ities at several levels. In th e past, in dividual surgical problem s were dealt with in isolation . Th is led to th e “birth day syndrom e,’’ in wh ich a ch ild would com e back n early every year to h ave surgery on an oth er part of th e lower extrem ity. In reality, con tractures or deform ities at any level

Hip Surgery on th e spastic h ip accoun ts for th e largest n um ber of procedures perform ed on th e pediatric h ip. Th ese ch ildren have sign ifican t h ip disease initiated by m uscle im balance, the developm ent of soft tissue contractures, subsequent bony deform ity, and ultim ately hip subluxation and dislocation. The contractures involve the hip flexors (psoas an d rectus fem oris) an d th e h ip adductors. With progressive con tracture, th e axis of h ip rotation is altered an d secon dary osseous changes develop. Fem oral anteversion is presen t at birth, rem ains persistent in these children, an d accentuates the rate at which hip subluxation and dislocation occur (Fig. 11.17). Radiographs of the spastic h ip frequently are m isin terpreted as dem onstrating significant valgus, when in fact they are dem onstrating anteversion. It is important to realize that children with CP are born with n orm al h ips an d that subsequen t ch an ges are the result of n eurom uscular im balan ce. Un treated, th ese h ips m ay progress to severe subluxation or dislocation . Alth ough it is som ewhat controversial, there seem s to be general agreem en t that a dislocated hip has a 50% chance of becom ing pain ful. It is th is observation , an d th e im proved seatin g position , th at m akes the best argum ent for operative reconstruction of a subluxed or dislocated hip. Of course, the

Figure 11.17 Anteroposterior radiograph of the pelvis in a child

with spastic quadriplegic cerebral palsy. The right hip demonstrates severe subluxation and uncovering. (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, CA.)


best way to m an age th ese ch ildren is to preven t h ip subluxation through early screenin g, spasticity m anagem en t, and appropriate surgery. Physical th erapy, botulin um toxin in jection s, an d abduction splin tin g can be effective to m ain tain h ip ran ge of m otion and delay th e need for surgery. In general, children wh o h ave less th an 30 degrees of abduction an d/or a m igration in dex greater th an 25% are at risk for progressive subluxation and should be treated with adductor ten otomy. If a coexistin g h ip flexion con tracture exists, an iliopsoas recession should also be perform ed. For hips with m ore severe m igration indices (> 50% –60%), a varus derotational fem oral osteotomy is warranted. The varus portion of the osteotom y h elps redirect th e fem oral h ead so th at it poin ts m ore directly at the acetabulum , whereas the derotation is useful for correctin g fem oral an teversion . In severe cases, a form al open reduction m ay be required, an d, if acetabular dysplasia exists, a resh aping acetabuloplasty such as th e Dega or San Diego pelvic osteotomy sh ould be in cluded (Fig. 11.18). The m anagem ent of the older child with a fixed, pain ful, spastic h ip dislocation is problem atic. Total h ip replacem en t h as been reportedly successful, but in m any patien ts, arthroplasty is n ot considered appropriate. Resectional type arthroplasties, such as proxim al fem oral resection with soft tissue in terposition , can be effective but are clearly a salvage option. Knee Ham strin g con tractures and th e subsequent developm ent of kn ee flexion deform ities are com m on problem s in th e spastic child. Walking with flexed knees greatly increases the energy expenditure required for am bulation and can severely lim it th e fun ction al abilities of children with CP

Figure 11.18 Postoperative anteroposterior radiograph after bilateral varus derotational femoral osteotomies and Dega pelvic osteotomies. (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, CA.)

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Figure 11.19 Crouched gait in a child with cerebral palsy.

(Reprinted with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

(Fig. 11.19). Over tim e, excessive kn ee flexion can lead to patella alta, lengthening of the patella ten don , an d patellofem oral pain . It is im portan t to rem em ber th at crouch ed posture is n ot solely th e result of kn ee flexion deform ities: h ip flexion con tractures an d calcan eus deform ities of th e foot both contribute to the overall positioning. Sim ilar to th e h ip, con servative m easures such as physical th erapy, botulin um toxin in jection s, an d n igh ttim e exten sion splin tin g can be h elpful to m ain tain flexibility an d delay th e n eed for surgery. Gen erally, h am strin g len gth en ing is indicated for children with popliteal angles greater th an 40 degrees. Th is procedure in volves a ten otomy of th e sem iten din osus ten don an d a fractional lengthening of th e sem im em bran osus at th e m usculoten din ous jun ction . Som e surgeons also add a gracilis lengthening; in severe cases, a len gth en in g of th e lateral h am strin gs (i.e., biceps fem oris) m ay also be n ecessary. If children h ave a stiff knee durin g th e swin g ph ase of gait alon g with overactivity of th e rectus fem oris in swin g ph ase (based on gait an alysis), th e rectus fem oris can be tran sferred to th e distal h am strin gs to help improve dynam ic knee flexion. In cases of fixed kn ee flexion con tractures, a posterior capsulectomy or distal fem oral exten sion osteotom y is occasionally necessary. Recen tly, som e authors have advocated distal advancem ent of th e patella tendon along with th e exten sion osteotomy for th ose patien ts wh o h ave flexion contractures, patella alta, an d patellofem oral pain (Fig. 11.20).

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A,B

C Figure 11.20 Preoperative (A) and postoperative (B) lateral radiographs and (C) postoperative

anteroposterior radiograph of a left knee in maximum extension after treatment with distal femoralextension osteotomy with patellar advancement. The change in the patellar height can be quantified by relating the femur–tibia distance, (A), to the patella–tibia distance, (B). (Reproduced with permission from Stout JL, Gage JR, Schwartz MH, et al. Distal femoral extension osteotomy and patellar tendon advancement to treat persistent crouch gait in cerebral palsy. J Bone Joint Surg. 2008;90:2470–2484.)

Foot and Ankle Equinus deform ities of the ankle are probably the m ost com m on deform ities seen in CP. Such positioning can lead to toe-walkin g an d decreased fun ction al ability. In h em iplegic ch ildren , equin ovarus deform ities are com m on , with the foot pointing down and in (Fig. 11.21). A recent study dem onstrated that in one-third of these patien ts, the equin ovarus deform ity was due to overactivity of th e posterior tibialis m uscle; in an oth er on e-th ird, th e cause was

an overactive anterior tibialis m uscle; and in the rem aining on e-th ird, th e deform ity was due to both m uscles. Equin ovarus at the an kle can lead to decreased toe clearan ce durin g swin g, in -toein g, an d trippin g. Plan ovalgus is a com m on foot deform ity seen in diplegic an d quadriplegic children. At first, there is ligam entous laxity and a contracture of th e heel cord. O ver tim e, the forefoot begin s to pron ate an d abduct an d th e h in dfoot develops valgus (Fig. 11.22). As th e deform ity progresses, th e posterior tibialis

Figure 11.21 Typical appearance of an

equinovarus foot in a patient with right-sided hemiplegic cerebral palsy. (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, CA.)


Figure 11.22 Bilateral posterior view of pes planovalgus.

(Reprinted with permission from Morrissy RT and Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

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stretch es an d becom es n onfunction al. These factors allow th e foot to collapse th rough th e arch . Spastic bun ion deform ity com m on ly complicates th e plan ovalgus foot as the equinovalgus foot position often forces the m edial border of th e great toe in to abduction . For both equin us an d equin ovarus deform ities, con servative m easures should be exh austed before considering surgery. Botulinum toxin injections, physical therapy, stretch in g casts, an d ankle–foot orthoses (AFOs) can be used to im prove dorsiflexion or to m ain tain existin g gain s. It is importan t to rem em ber th at alth ough th e calf m uscles are tigh t, th ey are also weak. Overzealous surgery can lead to overlength ening of the Achilles tendon, excessive weakn ess, an d a calcan eus gait. Most ch ildren wh o require surgery for an equinus contracture can be treated with a gastrocnem ius recession. This is perform ed at the m usculoten din ous jun ction an d h elps preserve m ore push off stren gth compared with open lengthening of th e Achilles ten don (Fig. 11.23). For ch ildren wh o h ave dorsiflexion greater th an 20 degrees sh ort of n eutral, an open slidin g or Z-lengthen in g is probably warran ted (Fig. 11.24). For ch ildren with equin ovarus deform ities, quan titative gait an alysis is extrem ely useful to determ ine which m uscle group is prim arily responsible. For flexible deform ities, a split

Figure 11.23 A gastrocnemius recession is performed by cut-

ting the fascia (but not the muscle) at the musculotendinous junction. This technique helps preserve push-off strength. (Reproduced with permission from Skaggs DL, Tolo VT. Master Techniques in Orthopaedic Surgery: Pediatrics. Philadelphia, PA: Lippincott Williams & Wilkins, 2008.)

Figure 11.24 Z-lengthening of the Achilles tendon is indicated

for more severe contractures. (Reproduced with permission from Skaggs DL, Tolo VT. Master Techniques in Orthopaedic Surgery: Pediatrics. Philadelphia, PA: Lippincott Williams & Wilkins, 2008.)

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B

A C Figure 11.25 Calcaneal lengthening osteotomy. (A) The calcaneus is cut 2–2.5 cm proximal to the

calcaneocuboid joint. (B–C) A trapezoidal bone graft is inserted to enhance talar coverage by the navicular. (Reproduced with permission from Skaggs DL, Tolo VT. Master Techniques in Orthopaedic Surgery: Pediatrics. Philadelphia, PA: Lippincott Williams & Wilkins, 2008.)

an terior tibial ten don tran sfer or split posterior tibial ten don tran sfer can h elp balan ce th e foot. In m ore rigid deform ities, a h indfoot osteotomy m ay also be necessary. Plan ovalgus feet th at h ave failed bracin g m ay be am en able to a lateral colum n len gth en in g. Th is procedure takes advantage of th e windlass m echanism to develop an arch an d correct th e h in dfoot. By placin g a wedge of bon e graft in th e calcan eal n eck, th e previously sh ort lateral colum n of th e foot becom es elon gated; th is h elps swin g th e foot into a m ore anatom ic position (Fig. 11.25). For the spastic bun ions, m ost authors feel th at stan dard bun ion procedures h ave an un acceptable rate of recurren ce; an d therefore, m ost prefer an arthrodesis of the first m etatarsophalangeal (MTP) joint as a defin itive procedure. Upper Extremity Th e upper extrem ity is also in volved in patien ts with h em iplegic or quadriplegic CP. In m ild cases, th e extrem ity m ay lack som e degree of coordin ation an d selective m uscle con trol; in severe cases, th e extrem ity m ay be extrem ely spastic with the typical appearan ce of th um b-in-palm , wrist flexion , forearm pron ation , an d elbow flexion (Fig. 11.26). Although deform ities m ay initially be dyn am ic, by the tim e ch ildren are 6 to 9 years of age, fixed con tractures usually develop. Th e goals in treatin g th e upper extrem ity are to improve its fun ction as a h elpin g h an d; to improve its gross function in graspin g, pinching, and releasing; and to im prove its appearan ce. Occupation al th erapy is h elpful for younger children to encourage the child to use the hand.

Botulin um toxin and occasion al splin tin g can h elp m anage forearm and elbow contractures. Surgical techniques are available to correct the thum b-in-palm deform ity, the instability of the first m etacarpoph alangeal joint, and the instability of the carpom etacarpal joint of the thum b. Wrist flexion deform ity h as been m an aged by ten don transfers, ten odesis, an d wrist fusion . In severe cases wh ere improved

Figure 11.26 Clinical photograph demonstrating the character-

istic appearance of a spastic upper extremity due to cerebral palsy. Note the elbow flexion, wrist flexion, and forearm pronation. (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, CA.)

Chapter 11: Pediatric Orthopaedics Medullary plate Dura mater

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Central canal Epidermis

Dorsal root Ventral root

Cerebrospinal fluid

Figure 11.28 Cross section of myelomeningocele. The abnorFigure 11.27 Spina bifida occulta. Spinous processes of L2 and L4 are visible (black arrows). An absent spinous process at L5 (white arrow) is consistent with spina bifida occulta in an otherwise normal child. (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

hygien e an d appearan ce are th e prim ary goals, selective ten otom ies m ay be appropriate.

Myelodysplasia (Spina Bifida) Pathophysiology Myelodysplasia, or spina bifida, can be divided into two m ain categories: spina bifida occulta and spina bifida cystica. Spina bifida occulta is present in 10% to 15% of the norm al population an d typically con sists of a benign defect in one or m ore of th e posterior elem ents of L4 –S1 (Fig. 11.27). Although rarely associated with lower spin al cord m alform ations (e.g., lipom en ingocele and teth ered cord), spina bifida occulta usually does not cause any problem s. Spina bifida cystica occurs when som e portion of the spinal canal herniates th rough the defect in the posterior elem en ts (Fig. 11.28). Depen din g on th e con ten ts of th e herniated cyst, the lesion m ay be term ed a m enin gocele (m enin ges only), myelocele (spinal cord and/ or nerves), or a m yelom en in gocele (both ). Th e un derlyin g etiology for myelodysplasia is the failure of the neural tube to close durin g early em bryogen esis. Th is results in a flaccid paralysis below the level of the lesion. Unlike CP, both m otor an d sensory functions are impaired. Although the areas of involvem ent are initially flaccid, it is not unusual for som e ch ildren to develop spasticity in the lower extrem ities later in life. Classification Myelodysplasia is generally classified by the level of n eurologic fun ction . Th e fun ction al m otor level is th e best m eans of determ ining prognosis, predicting deform ities, an d plannin g treatm ent. Thoracic level patients have alm ost no am bulatory potential because they lack active h ip

mal cord is part of the sac that has herniated out of the canal. (Reprinted with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

flexion an d knee extension (Fig. 11.29). Major issues in th ese ch ildren in clude th e developm en t of scoliosis an d/ or kyphosis. Prolonged wh eelchair use can lead to kn ee flexion contractures, and feet m ay develop equin us deform ities, wh ich inhibits the ability to fit shoes. High lum bar level children (L1 –L2) h ave variable am ounts of hip flexion and adduction (Fig. 11.30). Th ese patients have sim ilar issues as th e th oracic level ch ildren but m ay be at increased risk for h ip dislocation if th ere is un opposed force of th e iliopsoas and adductor m uscles. Midlum bar myelodysplasia (L3 –L4) patients h ave good quadriceps fun ction , wh ich is th e m ost im portan t determ inant of am bulatory ability (Fig. 11.31). As a result, they gen erally are able to walk with th e use of lower extrem ity orth oses an d crutch es. Th ese patien ts are at h igh risk for h ip dislocation . Th e im plication of th is is un clear sin ce dislocated h ips h ave n ot been proven to lim it th e am bulatory poten tial of th ese ch ildren . Because of sign ifican t abductor weakn ess, m idlum bar myelodysplasia patients usually walk with a Trendelenburg gait and m ay develop valgus at th e kn ee from th e lateral sway. Alth ough th e quadriceps are function al, knee flexion contractures can develop, which lead to crouched gait and increased energy requirem ents

Figure 11.29 Patients with thoracic-level myelodysplasia lack

motor function in the lower extremities and the legs lie, as they did in birth, in a position dictated by the effect of gravity. (Reproduced with permission from Broughton NS. Textbook of Paediatric Orthopaedics. London, England: WB Saunders, 1997.)

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Figure 11.32 L5-level myelodysplasia. There is flexion at the Figure 11.30 L1-level myelodysplasia. Flexion and external rota-

tion of the hips leads to an abducted posture from weak hip adductors. (Reproduced with permission from Broughton NS. Textbook of Paediatric Orthopaedics. London, England: WB Saunders, 1997.)

for am bulation. Patients with L4 fun ction will often develop a calcan eal foot deform ity due to th e un opposed action of th e an terior tibialis. Low lum bar level (L5) m yelodysplasia h ave adequate hip abductor strength in addition to stron g quadriceps function (Fig. 11.32). Most of these patients walk with a m in im al Tren delen burg gait usin g on ly AFO s. Th e in ciden ce of h ip problem s is low as is th e in ciden ce of scoliosis. Foot deform ities, h owever, occur quite frequen tly; th e m ost com m on deform ity is a calcaneal foot due to poor gastroc-

Figure 11.31 L3-level myelodysplasia: the hips lie in flexion and

adduction and the knees in extension or hyperextension from functioning quadriceps. There is no muscle power in the feet. (Reproduced with permission from Broughton NS. Textbook of Paediatric Orthopaedics. London, England: WB Saunders, 1997.)

hip and some flexion at the knee. Unopposed action of ankle dorsiflexors (due to weakness of the gastroc-soleus complex) leads calcaneus position of the feet. (Reproduced with permission from Broughton NS. Textbook of Paediatric Orthopaedics. London, England: WB Saunders, 1997.)

soleus fun ction . Th e fin al type of myelodysplasia is sacral level involvem ent. These children are generally free of spine an d hip problem s and am bulate well with AFOs. Foot abn orm alities are seen in 50% an d m ay be cavus, equin us, or valgus deform ities. One of the m ajor issues in these children is skin breakdown sin ce th ey are quite fun ction al but h ave decreased sen sation on th e plan tar aspect of their feet.

Presentation Myelodysplasia is generally diagnosed in utero. The iden tification of elevated α-fetoprotein in the m aternal blood (sampled at 15 –16 weeks) will trigger an am n iocen tesis. Th is study is quite defin itive for th e diagn osis of open n eural tube defects. Ultrasoun d h as also been sh own to be reason ably sensitive in th e diagnosis of myelodysplasia. Either way, m ost cases are identified prior to birth. After delivery (usually by cesarean section to avoid traum a to th e herniated sac), closure of the myelom eningocele is perform ed by a neurosurgeon within 48 h ours of birth. Approxim ately 80% of th ese ch ildren will survive th eir first year, an d 60% to 70% of patien ts will survive to adulth ood. Patien ts are gen erally referred for orth opaedic care at an early age to determ in e am bulatory poten tial an d m an age lower extrem ity deform ities. History and Physical Examination A careful h istory m ay elicit on e or m ore of th e m ajor risk factors for spin a bifida, in cludin g h istory of myelodysplasia in a previous pregnancy, in adequate folic acid intake, m atern al diabetes, an d m atern al use of valproic acid durin g the pregnancy. Folic acid supplem en tation, in particular, is the best m ean s of preventing neural tube defects and is a standard component of all prenatal vitam ins.


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Th e m ost importan t goal of th e physical exam in ation is to classify the neurologic level. This can be a far m ore challenging task than it first appears. In newborn s, spontaneous m otion can be th e result of reflex rath er th an volun tary m ovem en t. Even in older ch ildren , th ere m ay be gaps in the neurosegm en tation levels and side-to-side differences, which can m ake classification difficult. Periodic m anual m uscle testing of the entire lower extrem ity (preferably by the sam e exam iner) is the m ost accurate m ethod to determ in e th e fun ction al n eurologic level. In addition , skin (particularly around the feet) should be carefully exam ined for signs of redness an d potential breakdown. Much like a diabetic patien t, ch ildren with myelodysplasia lack protective sensation an d can easily develop severe pressure ulcers.

General Treatment Principles Much like children with CP, patien ts with myelodysplasia are best treated by a m ultidisciplinary team of pediatricians, urologists, physical th erapists, orth otists, n eurosurgeon s, an d orthopaedic surgeon s. Neurosurgical consultation, in particular, is extrem ely importan t. Many children with myelodysplasia h ave sh un ts placed to con trol hydroceph alus; proper follow-up is necessary to prevent shunt blockages an d th e resultin g hydroceph alus. In addition , ch ildren should be m on itored for signs of a tethered cord. Th ese sign s in clude ch an ges in bladder fun ction , in creased lower extrem ity spasticity, sudden change in m otor strength an d function, or rapidly progressive scoliosis (Fig. 11.33). It is importan t to rem em ber th at alm ost all ch ildren with spina bifida will sh ow signs of spinal cord tetherin g on m agn etic resonance im aging (MRI) due to scar tissue created at th e tim e of myelom eningocele closure. However, if clinical findings support the MRI, then patients sh ould be referred for n eurosurgical deteth erin g. Th is is gen erally successful in stabilizing the neurologic status and preven ting further deterioration . Any surgery on patients with myelodysplasia should be perform ed in a latex-free en viron m en t. Because of early exposure to latex durin g in fan cy, th e in ciden ce of latex allergy is increased in these ch ildren and has been reported to be

Figure 11.33 Magnetic resonance image of a child with

myelomeningocele shows radiographic evidence of a tethered cord. The conus medullaris is low-lying. The placed is displaced posteriorly and is adherent to the dorsal dura (arrowheads). (Reproduced with permission from Weinstein SL. The Pediatric Spine. Philadelphia, PA: Lippincott Williams & Wilkins, 2001.)

as high as 3% to 7%. Perform ing surgery in a norm al latex en viron m en t can risk an an aphylactic reaction with a precipitous drop in blood pressure. Another issue that com m on ly arises in the care of children with myelodysplasia is path ologic fracture due to severely osteoporotic bon e. These fractures often present with warm th , redn ess, an d swellin g but m in im al pain due to impaired sensation (Fig. 11.34). As a result, they can

Figure 11.34 (A) This boy with thoracic level spina

bifida presented with a chief complaint of painless leg swelling. The leg was warm to touch. (B) Radiographs demonstrate copious new bone formation. (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

A

B

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often be con fused with osteom yelitis or oth er in fection . Gen erally, careful palpation will reveal som e crepitus an d in flam m atory m arkers such as eryth rocyte sedim en tation rate (ESR) or C-reactive protein (CRP) level will be norm al. Th ese fractures are best m an aged by sh ort-term im m obilization , often with soft bulky dressin gs or soft braces. Prolon ged im m obilization in h ard casts m ay lead to worsen ed osteopen ia an d skin breakdown .

Treatment of Regional Deformities Spine Th e in ciden ce of scoliosis or kyph osis in ch ildren with spin a bifida is approxim ately 60%. The vast m ajority of these patients have th oracic or h igh lum bar neurologic levels. Sin ce th ese patien ts are usually n on am bulatory, th e goal of treatm en t is to preserve adequate sittin g balan ce an d lim it progression of th e deform ity. In gen eral, curves less th an 20 degrees sh ould be observed. Curves between 20 and 40 degrees can be treated with a brace to improve uprigh t posture an d sittin g balan ce; h owever, th ere is n o eviden ce th at th e use of a spin al orth osis will preven t curve progression . Curves greater th an 50 degrees an d pelvic obliquity th at adversely affects sittin g balan ce m ay require spin al fusion an d in strum entation (Fig. 11.35). Surgery is gen erally perform ed from both an an terior an d posterior approach because th e lack of posterior bony elem en ts can

increase the risk of pseudarthrosis if bone graft is applied on ly posteriorly. Even with th is dual approach , complications are com m on: 10% to 30% of patients will have loss of n eurologic or bladder fun ction , pseudarth rosis, or wound breakdown after surgery. Kyph osis can occur in 10% to 15% of ch ildren with myelodysplasia. Un treated, progressive kyph osis can lead to loss of truncal height, decreased pulm onary fun ction, and skin breakdown over the apex of the deform ity. Kyph ectomy, wh ich in volves vertebral resection at th e apex of th e kyph otic segm en t followed by in strum en tation usually to the pelvis, is the m ost accepted form of surgical treatm ent. Prior to any surgery in which the thecal sac m ay be ligated, it is im portan t to verify proper fun ction of th e sh unt to preven t acute hydroceph alus. Hips Managem ent of hip dislocation and hip dysplasia in ch ildren with myelodysplasia is som ewh at con troversial but sh ould be guided by the level of n eurologic fun ction. Thoracic level patien ts rarely dislocate th eir h ips because th ey lack any m uscle activity about the hip. Children with upper lum bar level spin a bifida usually sh ould n ot un dergo procedures to recon struct dislocated h ips sin ce th e status of th e h ip will n ot affect th e ch ild’s ability to walk. If h ip flexion contractures are greater th an 20 to 30 degrees and

Figure

A

B

11.35 Thirteen-year-old

boy with thoracic-level myelomeningocele and progressive curve and with pelvic obliquity. Posterior spine fusion to the pelvis stabilizes the curve and provides a level-sitting platform. (Reprinted with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)


253

Figure 11.36 Community ambu-

latory child with L3 functional level. He uses Lofstrand crutches and bilateral ankle–foot orthoses. He is able to ambulate with a swing-through gait despite a unilaterally dislocated hip. (Reprinted with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

A

interfere with bracin g, hip flexor release or anterior capsulotomy m ay be in dicated. In ch ildren with m idlum bar myelodysplasia, m ost auth ors prefer to leave bilateral dislocation s untreated. Select un ilateral dislocations m ay warran t reduction ; h owever, th is is con troversial because of th e high inciden ce of recurrent dislocation (Fig. 11.36). Again , any hip con tracture that in terferes with bracing or walking sh ould be released. Low lum bar and sacral level spin a bifida are at low risk for h ip dislocation sin ce m uscle forces around the hip are well balanced. For th ose dislocations that do develop, anterior releases and bony surgery sh ould be perform ed as n eeded to ach ieve a stable, con cen tric h ip reduction . Knee Several differen t kn ee deform ities m ay develop in spin a bifida. Exten sion con tracture, flexion con tracture, an d valgus deform ity h ave all been reported depen ding on the specific pattern of m uscle fun ction. Knee flexion con tractures are com m on, particularly in patients with thoracic or upper lum bar spin a bifida. If a ch ild predom in an tly uses a wh eelch air, treatm en t m ay n ot be n ecessary; h owever, if th e deform ity in terferes with bracin g or am bulation , th en posterior soft tissue release an d/ or distal fem oral exten sion osteotomy is in dicated. Patien ts with m idlum bar myelodysplasia are at h igh risk for severe kn ee valgus due to th eir Trendelenburg gait. Crutches along with knee–ankle–foot orth oses (KAFO s) can h elp protect th e kn ees in th ese patients. Foot and Ankle Foot deform ities are extrem ely com m on in spin a bifida, occurring in up to 75% of patients. In patients with higher levels of in volvem en t, equin us con tractures, vertical talus, an d rigid clubfoot deform ities predom in ate. Th e goal of treatm en t is a supple, plantigrade foot th at easily accom m odates sh oewear. Since m ost children will require braces, ten o-

B

tom ies (with excision of a ten don segm en t) are preferred over ten don len gth en in gs sin ce flail extrem ities are easier to deal with th an recurren t deform ities. Sim ple equin us con tractures are best treated with an open Ach illes ten otomy. A vertical talus will require open reconstruction with release of th e tigh t an terior structures. Open reduction of th e talon avicular join t with pin fixation is th e n orm . Clubfoot deform ities can be in itially treated with early m an ipulation an d castin g; h owever, a h igh er percen tage of patien ts will require open release compared with idiopath ic clubfeet. In certain severe cases, a talectomy m ay be required as a salvage option . In ch ildren with m id to low lum bar m yelodysplasia, calcan eal foot deform ities are m ore com m on due to un opposed pull of th e an terior tibialis m uscle. Th ese ch ildren are best treated with ten otom y an d bracin g sin ce tran sfers of the anterior tibialis tendon have not been sh own to provide added ben efit. Equin ovarus an d equin ovalgus deform ities m ay also be seen. Equin ovarus deform ity is best treated by release of th e posterior tibialis ten don ; a calcaneal osteotomy can be added for cases of residual hindfoot varus. Equinovalgus feet th at fail bracing can be treated by peroneal and calcaneal lengthen ing. Sacral level patients can also have equinus or valgus but m ay also develop cavus deform ities. If th is latter deform ity is supple, release of th e peron eus lon gus an d plan tar fascia m ay con trol th e deform ity. In m ore severe cases, a dorsiflexion osteotomy of th e first ray or even a calcan eal osteotomy m ay be n ecessary.

Charcot–Marie–Tooth Disease Charcot–Marie–Tooth (CMT) disease is th e m ost com m on form of hereditary m otor sensory neuropathy. Other neuropath ies are prim arily adult diseases with out orth opaedic implications; thus, th ey are not included in this section. CMT disease itself is actually a group of different diseases with differen t gen otypes but sim ilar ph en otypes.

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A,B

C

Figure 11.37 (A) Front view of the lower legs and feet of a 16-year-old boy with Charcot–Marie–

Tooth disease. His calves are thin, and he has symptomatic cavus feet. Clawing of the toes is minimal. (B) Posterior view demonstrates moderate heel varus. (C) The cavus foot deformity is most apparent when viewed from the medial side. A mild flexion deformity of the great toe interphalangeal joint is present. (Reprinted with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Pathophysiology and Classification CMT disease is a progressive demyelin atin g periph eral n europathy. Two m ajor form s of CMT disease exist. Th e type I form is usually in herited in an autosom al dom in ant fashion an d accoun ts for 60% to 80% of all patien ts with CMT disease. Th e gen etic defect in 70% of type I patien ts is a duplication in th e periph eral myelin protein (PMP) gen e on ch rom osom e 17. Th is m utation causes an overproduction of th e protein , wh ich causes demyelin ation of th e peripheral nerves. The type II form of CMT disease is inherited in an X-lin ked fash ion an d is respon sible for 20% to 40% of all cases. Type II CMT disease is caused by a deficiency in the connexin gen e, wh ich codes for a gap jun ction protein th at en h an ces con duction between periph eral n erves. Deficien cy in th is protein results in an axon al neuropathy. Presentation Patien ts with CMT disease typically present during early adolescen ce with progressive cavovarus deform ities of th e feet, alth ough som e children present during preschool years (Fig. 11.37). This characteristic foot deform ity is caused by the pattern of peripheral demyelination in CMT disease, wh ich affects distal m uscle groups first. Th is results in weakness of the tibialis anterior, peron eus brevis, an d foot in trin sics with relative preservation of peron eus lon gus, posterior tibialis, an d toe exten sor stren gth . Th e discrepan cy in stren gth allows th e peron eus lon gus to over-

power its an tagon ist, th e tibialis an terior, leadin g to plan tarflexion of th e first ray. In an effort to balan ce th e tripod of th e foot, th e h in dfoot compen sates by swin gin g in to a varus position. As a result, patients ten d to overload the lateral border of the foot and often present with calluses in th is location . Atrophy an d con tracture of th e in trin sic m usculature of th e foot lead to clawin g of th e toes, con tracture of th e plan tar fascia, an d elevation of th e arch . Plan tar flexion of th e m etatarsal heads can lead to increased pressure in these areas and m etatarsalgia. Th e in n ervation of th e h an d is also affected in CMT disease, wh ich leads to in trin sic atrophy. Han d in volvem en t, h owever, usually does not develop un til late in th e disease course. Hip dysplasia can also occur, perh aps because of subtle weakn ess of th e proxim al m usculature about the hip. Scoliosis is seen in up to 37% of adolescen ts with CMT disease. Deform ities are sim ilar to idiopath ic curves but ten d to have m ore kyphosis than lordosis.

Physical Examination Observation of gait in patients with CMT disease usually reveals a drop foot durin g swin g. A steppage gait can develop, which is ch aracterized by hyperflexion of th e knee an d hip in an attempt to help clear th e foot. Toe extension durin g swin g can also be seen as th is h elps com pen sate for the weakness of the prim ary ankle dorsiflexors. Lower extrem ity exam in ation will reveal dim in ish ed deep ten don


A

B

Figure 11.38 The Coleman block test for determination of hind-

foot flexibility. The flexible varus deformity of the hindfoot will correct to valgus when the plantar flexed first metatarsal is allowed to drop down off the edge of the block of wood. Failure to correct to valgus indicates the need for surgical correction of the hindfoot, in addition to the procedures on the forefoot. (Reproduced with permission from Coleman SS, Chestnut WJ. A simple test for hindfoot flexibility in the cavovarus foot. Clin Orthop. 1977;123:60–62.)

reflexes an d decreased calf circum feren ce from global atrophy. Distal sen sation is usually decreased to all m odalities. Evaluation of the cavovarus foot in patien ts with CMT disease begin s with a careful assessm en t of th e skin . Lateral overloadin g m ay cause large calluses alon g th e lateral border of th e foot. As patien ts m ay be partially in sen sate, it is important to identify areas at risk for breakdown to preven t th e form ation of deep ulcers. To develop an appropriate treatm en t plan for th e cavovarus foot, it is essen tial to assess the flexibility of hindfoot. This is best done by using the Colem an block test (Fig. 11.38). This test is perform ed by having th e patien t stand on a block with the head of the first m etatarsal hangin g free over the m edial edge. If the hindfoot varus is a compensatory response to plantar flexion of the first ray (i.e., flexible), the heel will correct to n eutral on th e block. If th e varus deform ity h as becom e rigid over tim e, it will n ot correct. Hands should be exam in ed by m anual m uscle testing to m on itor atrophy of th e in trin sic m usculature. In certain cases, han d dynam om eters m ay be useful to provide quantitative data about the change in m uscle strength over tim e. Hips sh ould be ran ged and exam ined for subtle in stability. A standard scoliosis exam ination should be perform ed (see pediatric spine section) to screen for spin al deform ity.

Radiographs Stan din g lateral radiograph s of th e foot will dem on strate the characteristic findings of the cavovarus deform ity. Usually, the angle of the inferior border of the calcaneus and the tibia exceeds 30 degrees, in dicating th at th e ankle is actually dorsiflexed not plantarflexed. The apparent equinus of th e deform ity is usually due to plantar flexion

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Figure 11.39 Lateral radiograph of a typical cavovarus foot due

to Charcot–Marie–Tooth disease. Note the increase in Meary angle from plantar flexion of the forefoot relative to the hindfoot. (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, CA.)

of th e forefoot rath er th an plan tar flexion of th e an kle (Fig. 11.39). This can be quantified by m easurin g Meary angle, the angle between the long axis of the talus and the first m etatarsal shaft. In the n orm al foot, th ese two axes lin e up and the angle is 0 degrees. With progressive plantar flexion of th e first ray, Meary an gle in creases. Hibb angle is defin ed as th e an gle between th e lon g axis of th e calcan eus and the first m etatarsal shaft. Norm ally, th is an gle is greater th an 150 degrees; in creased cavus results in a sm aller Hibb angle.

Special Studies Gen etic testin g is h elpful to diagn ose m any patien ts with CMT disease. However, since m any different genotypes cause a sim ilar disorder, a n egative test does n ot rule out th e disease. In gen eral, patien ts suspected of h avin g CMT disease sh ould be referred to a n eurologist for electromyography an d n erve con duction testin g. Patien ts with type I CMT disease tend to have decreased nerve con duction velocity on electrodiagnostic studies. In patients with type II CMT disease, electrodiagn ostic studies typically dem on strate n orm al or m inim ally decreased conduction velocity but decreased am plitude of action poten tials. In rare cases, th e com bin ation of gen etic testin g an d electrophysiologic testin g is still in sufficien t to m ake th e diagn osis. In th ese situations, a sural n erve biopsy should be perform ed. Differential Diagnosis Many different diseases can produce a sim ilar cavovarus foot deform ity as does CMT disease, includin g spinal cord tum ors, Friedreich ataxia, diastem atomyelia, an d syrin gomyelia. A un ilateral cavovarus deform ity, in particular, sh ould raise suspicion of spinal cord pathology. It is importan t to rem em ber that a cavovarus foot is never norm al; if a patient does n ot have electrodiagnostic or genetic

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eral n erves. Th is section will focus on th e m ost com m on and representative m uscular dystrophy seen in children, Duch en n e m uscular dystrophy.

Figure 11.40 Postoperative lateral radiograph of the same

foot from Figure 11.39 after dorsiflexion osteotomy of the first metatarsal, plantar fascia release, and transfer of the extensor hallucis longus from the toe to metatarsal head (Jones transfer). Note the improvement in the Meary angle and the clawing of the great toe. (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, CA.)

eviden ce to support th e diagn osis of CMT disease, a spin al MRI sh ould be ordered.

Treatment Th ere is n o clin ically proven m edical treatm en t th at h alts or slows progression of CMT disease. Treatm en t, th erefore, is directed at correctin g deform ities an d m axim izin g fun ction . Con servative m easures are largely un successful for treatin g cavovarus feet. Occasion ally, sh oe in serts can be useful to elevate th e m etatarsal h eads an d reduce th e symptom s of m etatarsalgia. In patien ts with sign ifican t drop foot gait, an AFO can improve toe clearance by preventin g excessive plan tar flexion durin g swin g ph ase. Early in the disease process, transfer of the peron eus longus to the peron eus brevis an d plan tar fascia release can rem ove th e deform in g forces an d lim it progression of th e deform ity. O n ce th e first ray becom es plan tar flexed, a dorsiflexion osteotomy of th e first m etatarsal alon g with ten don tran sfers is necessary to balan ce th e foot. If the hin dfoot is rigid, as assessed by the Colem an block test, a calcaneal osteotomy sh ould be added to correct th e varus deform ity (Fig. 11.40). Claw deform ities of th e great an d lesser toes can be m anaged by Jon es transfers of th e exten sor tendon s to th e m etatarsal n ecks. A triple arth rodesis sh ould be avoided if at all possible, alth ough in severe, rigid deform ities, it m ay be th e on ly m ean s of obtain in g a plan tigrade foot.

Muscular Dystrophy Muscular dystroph ies are a group of gen etic diseases, ch aracterized by progressive deterioration of skeletal m uscle. By definition , the pathologic changes are confined to th e m uscle itself with n o abn orm alities seen in th e periph -

Pathophysiology Th e un derlyin g etiology of Duch en n e m uscular dystrophy is the absence of the m uscle protein dystrophin . The gene respon sible for producin g dystroph in resides on th e Xch rom osom e, wh ich explains why Duchenne m uscular dystrophy is in h erited in an X-lin ked m an n er. In m ost cases, th e gen etic defect is a fram esh ift m utation th at results in n o protein bein g produced. Norm ally, dystroph in acts to stabilize th e cell m em bran e cytoskeleton in m uscle. Absen ce of dystroph in leads to in creased fragility of th e m yofiber m em brane and leakage of cellular contents into the extracellular space. This creates an inflam m atory response that results in loss of m uscle fibers and fibrosis of the m uscle. Presentation and Natural History Boys with Duch enn e m uscular dystrophy typically presen t between ages 3 an d 8. Th e presen tin g com plain t is often a waddlin g gait, difficulty with stairs, clum sin ess, or progressive lower extrem ity weakn ess. Th e m uscle weakn ess that develops is sym m etric, and proxim al m uscles are affected before distal m uscles. Lower extrem ity in volvem en t ten ds to precede upper extrem ity in volvem en t by 3 to 5 years. Weakness of hip extensors leads to anterior pelvic tilt and compensatory lum bar lordosis. In addition, weak abductors can result in a Trendelenburg gait. Ch ildren m ay also present with ankle equinus due to fibrosis an d contracture of the gastroc-soleus complex. As the disease progresses, walkin g becom es m ore difficult. By age 12, m ost patien ts with Duch en n e m uscular dystrophy becom e fulltim e wheelchair users. Once patients lose the ability to am bulate, scoliosis develops in the vast m ajority of patients. Spinal deform ity tends to progress relentlessly and can complicate worsening pulm on ary function due to a weaken ed diaph ragm an d ch est wall. Death usually occurs in the second or third decade of life due to respiratory failure. History and Physical Examination Sin ce Duch en n e m uscular dystrophy dem on strates Xlinked inheritance, any fam ily history of the disease should prompt an early workup. O n e-th ird of all cases, h owever, are due to spontaneous m utations, so lack of fam ily history is by n o m ean s conclusive. Any young boy wh o h as a h istory of progressive clum sin ess or weakn ess sh ould be evaluated for m uscular dystrophy. While tripping and falling are com m on parental complain ts in the orthopaedic clinic, a boy wh o is fallin g m ore frequen tly th an h e did in th e past sh ould be taken seriously. O bservation of th e ch ild walkin g m ay reveal a waddlin g gait due to lum bar lordosis an d abductor weakn ess.


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this task and will often use their upper extrem ities to help exten d th eir kn ees an d h ips. Ch ildren wh o appear to “walk’’ their hands up their legs to help raise th e trunk into an upright position have a positive Gowers sign (Fig. 11.42). As th e disease progresses, ch ildren often develop kn ee an d h ip flexion con tractures. As th e ch ild becom es m ore depen den t on a wh eelch air, th e spin e sh ould be carefully m on itored for sign s an d symptom s of scoliosis.

Figure 11.41 Pseudohypertrophy of the calf in the setting of

weakness suggests Duchenne muscular dystrophy. (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Toe-walking can also be seen from fibrosis and contracture of th e triceps surae. Although th e gastroc-soleus m uscle is weaker than norm al, the m uscle belly often appears enlarged. This fin din g is term ed “pseudohypertrophy,’’ is presen t in approxim ately 85% of ch ildren with Duch en n e m uscular dystrophy, and results from fibro-fatty replacem en t of the m uscle fibers (Fig. 11.41). In these cases, ran geof-m otion testin g of th e an kle will reveal decreased an kle dorsiflexion , alth ough a true equin us con tracture does n ot typically develop for several years. Careful m an ual m uscle testin g of ch ildren with Duch en n e m uscular dystrophy will reveal weakn ess in the proxim al m uscle groups. The m ost classic and useful screening test for Duchenne m uscular dystrophy is the Gowers sign . Th is test is perform ed by askin g th e ch ild to sit on th e floor of th e exam in in g room an d to stan d up quickly with out assistan ce. Patien ts with m uscular dystrophy an d proxim al m uscle weakn ess will h ave difficulty completin g

Figure 11.42 Weakness of proxi-

mal muscles from muscular dystrophy causes children to use their upper extremities to manually assist in knee extension and to achieve an upright stance. (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Diagnostic Studies If a diagn osis of m uscular dystrophy is suspected, th e first step is to m easure th e creatine kin ase level in the blood. In n orm al patien ts, th e creatin e kin ase level is less th an 300 U/ L; patien ts with m uscular dystrophy can h ave values greater th an 10,000 U/ L. Ch ildren with elevated blood creatin e kin ase levels sh ould be referred for gen etic testing, which can yield a defin itive diagnosis in up to 95% of patien ts. For th ose few patien ts in wh om th e diagn osis is still uncertain after gen etic testin g, a m uscle biopsy m ay be n ecessary. By perform ing a Western blot test on th e biopsy specim en , one can determ in e conclusively wheth er or not dystroph in is presen t. Differential Diagnosis Th e differen tial diagn osis of Duch en n e m uscular dystrophy in cludes oth er form s of m uscular dystrophy an d m yoton ic dystrophy. Becker m uscular dystrophy is a m ore ben ign disease th at also results from a m utation in th e dystroph in gen e. In con trast to Duch en n e disease, th e deletion in Becker m uscular dystrophy results in eith er a truncated dystrophin m olecule or lower am ounts of norm al dystrophin. Becker m uscular dystrophy is characterized by sim ilar pathology but a m ilder disease course than Duch en n e m uscular dystrophy. Lim b girdle m uscular dystrophy actually refers to a large group of m uscle diseases th at are ch aracterized by progressive m uscle deterioration , predom inantly in the m uscles of th e pelvic an d sh oulder girdle. Most cases are in h erited in an autosom al recessive m anner; on set of symptom s is often in late adolescen ce or early adulth ood. In gen eral, th e clin ical course is m ore ben ign th an in Duch en n e m uscular dystrophy. Gen etic tests for dystroph in abn orm alities will

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be n egative, but m uscle biopsy will yield a defin itive diagnosis. Facioscapulohum eral dystrophy is in herited as an autosom al dom inant trait. It h as a highly variable age of on set an d severity. Weakn ess typically in volves th e sh oulder girdle an d facies. Classically, patien ts dem on strate an in ability to wh istle. The m ost com m on form of myotonic dystrophy in ch ildren is con gen ital m yoton ic dystrophy. Th e disease is caused by a trinucleotide repeat on a n on coding region of ch rom osom e 9. Th is results in deficien t am oun ts of myotin protein kin ase, wh ich is importan t in ribon ucleic acid m etabolism . Th ese ch ildren h ave profoun d hypoton ia at birth an d often require ven tilator assistan ce to breath in the newborn period. Those who survive becom e progressively stronger and can usually walk indepen dently by age 5. In th is period, equin us con tracture is com m on sim ilar to patien ts with Duch en n e m uscular dystrophy. Th e two diagn oses, h owever, are easily distin guish ed on th e basis of the history of hypotonia and developm ental delay and the location of th e weakn ess. Patien ts with myoton ic dystrophy typically dem on strate distal weakn ess rath er th an th e proxim al weakn ess th at ch aracterizes Duch en n e disease. Two other distinguish ing features of myotonic dystrophy are th e presen ce of myoton ia (m ain ten an ce of m uscle con traction even after th e patien t tries to relax) an d th e ch aracteristic droopin g face.

Treatment Th e m ost prom isin g m edical treatm en t for Duch en n e m uscular dystrophy is the use of corticosteroids. Steroids are though t to alter th e disease process by stabilizin g th e myofiber m em bran e an d reducin g th e in flam m atory respon se caused by leaking cell conten ts. Several recen t studies have proven th e efficacy of corticosteroids in prolon gin g am bulatory ability, preservin g pulm on ary fun ction , an d delayin g the onset of scoliosis. In one study, one-third of patients receivin g treatm en t were still walkin g at 18 years of age. Subjects in th e treatm en t group were also foun d to h ave 40% greater forced vital capacity and a 50% lower rate of scoliosis th an controls. The ben efits of prolonged steroid therapy need to be balan ced with the risks, which include weigh t gain , osteopenia, and cataracts. O rth opaedic treatm en t gen erally focuses on m axim izin g am bulatory poten tial an d treatin g spin al deform ity. Early in th e disease process, physical th erapy an d appropriate use of lower extrem ity orth oses can delay or lim it th e developm en t of con tractures. As m uscle weakn ess worsen s an d con tractures do develop, surgical release of h ip an d knee flexion deform ities m ay help preserve walking ability, alth ough such surgery is rarely perform ed curren tly. Equinus and equinovarus contractures resistant to conservative m odalities can be treated with Achilles ten don len gth en in g an d/or tran sfer of th e posterior tibial ten don (Fig. 11.43). As ch ildren lose th e ability to am bu-

Figure 11.43 A boy with Duchenne muscular dystrophy and a

severe equinovarus foot deformity. (Reproduced with permission from Chapman MW. Chapman’s Operative Orthopaedics. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 1993.)

late, adaptive equipm ent such as power wheelchairs are essen tial to allow in depen den t fun ction . O n e of th e m ajor respon sibilities of an orth opaedic surgeon wh o cares for the child with Duchenne m uscular dystrophy is the m anagem ent of spinal deform ity. Scoliosis tends to progress rapidly on ce th e ch ildren becom e wh eelch air boun d. Un fortunately, th is occurs at the sam e tim e that cardiac an d pulm on ary fun ction declin e sh arply. As a result, th e gen eral recom m en dation is to operate on curves on ce th ey reach 20 degrees, before cardiopulm on ary fun ction decreases to a point that surgery is dangerous. Surgery usually consists of posterior spin al fusion and instrum entation to th e pelvis.

Arthrogryposis Th e term arthrogryposis actually applies to a variety of con dition s th at are ch aracterized by decreased fetal m ovem en t an d congenital joint contractures. Collectively, the inciden ce of arth rogryposis is approxim ately 1 per 3,000 live birth s. Th e in ciden ce of am yoplasia, th e m ost com m on type of arthrogryposis, is 1 in 10,000.

Pathophysiology Th e fin al com m on path way th at causes arth rogryposis is decreased fetal m ovem en t, wh ich leads to m ultiple join t con tractures in utero. This lack of m otion is m ost often due to failure of skeletal m uscle developm en t due to an un derlying n europathic or myopathic abnorm ality. Occasion ally, space lim itations in utero or m aternal disease can lim it fetal m obility. Although m ajor joints initially develop norm ally from an em bryological stan dpoint, lack of m ovem en t in


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utero leads to fibrosis of th e join t capsules, atrophy an d fibrosis of ten don s, an d an absen ce of skin creases. Several inh eritance patterns have been described, but m ost cases of arth rogryposis are sporadic.

Classification Arthrogryposis can be classified into three general categories based on th e degree of nonm usculoskeletal organ involvem ent. Group 1 affects only the lim bs and in cludes the m ost typical form of arthrogryposis, amyoplasia. Group 2 disorders affect th e abdom in al viscera an d oth er organ s in addition to th e lim bs. Examples include m ultiple pterygium syndrom e and Larsen syndrom e. Group 3 condition s involve the CNS in addition to the joint contractures. Presentation Ch ildren with classic arthrogryposis typically present soon after birth with m ultiple rigid join t contractures, absent skin creases, an d atrophy of th e lim bs. The m ost com m on appearance is the waiter’s tip posture caused by shoulder in tern al rotation an d adduction , elbow exten sion , an d wrist flexion (Fig. 11.44). Lower extrem ities usually dem on strate knees that are stiff in either flexion or extension an d

Figure 11.45 Distal arthrogryposis. Characteristic hand is the

result of ulnar deviation at the metacarpophalangeal (MCP) joints. Notice the deeply cupped palm and webbing of the MCP joint of the thumb. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

equin ovarus deform ities of th e foot. O n e form of arth rogryposis, called distal arthrogryposis, presen ts with prim arily hand and foot involvem ent (Fig. 11.45). Th ese children h ave typical overlappin g fin gers an d th um b in palm deform ities in addition to clubfoot or vertical talus deform ities. Unlike m any syndrom es, children with arthrogryposis h ave norm al intelligence an d actually perform better than average in sch ool.

History and Physical Examination Ath orough h istory sh ould be perform ed to screen for oth er poten tial diagn oses in cludin g a n um ber of gen etic syn drom es. Moth ers often report decreased fetal m ovem en t in utero. Physical exam in ation sh ould determ in e wh ich lim bs are involved an d wh at part of each lim b is prim arily affected. Cutaneous exam ination reveals absent skin creases and spindle-sh aped extrem ities; sensory exam inations are usually n orm al. Th e ran ge of m otion of each join t sh ould be carefully m easured. Affected join ts usually dem on strate m arked lim itation of both active and passive m otion alth ough m ost retain at least a sm all degree of m otion . Hip m otion, in particular, is relatively spared especially in flexion and exten sion. Foot exam in ations typically reveal an equin ovarus deform ity from a rigid clubfoot or a rocker bottom deform ity from a vertical talus. Th e spin e sh ould also be exam ined for evidence of scoliosis, which can occur in 2% to 70% of patients. Figure 11.44 Arthrogryposis multiplex congenital. The picture shows the classic limb position and fusiform limbs lacking flexion creases. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Differential Diagnosis Since as m any as 150 different syndrom es can exhibit features of arthrogryposis; the m ost importan t step in m akin g

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the diagnosis of amyoplasia or classic arthrogryposis is rulin g out an oth er kn own gen etic syn drom e. Multiple pterygium syn drom e resem bles amyoplasia in term s of th e m ultiple join t con tractures. However, den se, fibrotic webbin g will be seen across th e flexor surfaces of the kn ee in particular (Fig. 11.46). Th ese ch ildren will also h ave gen itourin ary an d cran iofacial in volvem en t. Larsen syn drom e is officially considered a group 2 disorder but has m any distin guish ing features compared with amyoplasia. Children with Larsen syn drom e have a characteristic facial appearance (flatten ed face, depressed n asal bridge, an d widely set eyes) an d join t dislocation s due to ligam en tous laxity. Th ere is also a h igh in ciden ce of spin al deform ity in th is con dition , particularly cervical kyphosis. Occasionally, som e skeletal dysplasias that exhibit restricted join t m otion (e.g., diastrophic dysplasia) can be con fused with amyoplasia. Usually, th e fin din gs of sh ort stature an d lim b sh orten in g are sufficien t to differen tiate th ese diagn oses.

Treatment Th e two m ajor goals of treatm en t are m axim izin g am bulatory ability an d upper extrem ity fun ction to allow in depen den t fun ction in g for activities of daily livin g. It is importan t to rem em ber th at arth rogrypotic join ts fun ction poorly for a n um ber of different reason s, includin g a thickened join t capsule, fibrotic tendons, atrophied m uscles, tight skin, and poorly developed bursa. Th erefore, even th e best surgical option s can n ot be expected to recreate n orm al an atom y nor yield freely m obile joints. Depen din g on th e severity of th e con dition , early stretchin g and cast correction is useful to m inim ize deform ity. Hip deform ities are com m on in arth rogryposis an d usually con sist of dislocation an d con tracture (Fig. 11.47).

Figure 11.46 Multiple pterygium syndrome. Note the popliteal

webbing. Severe limitation of trunk growth was caused by vertebral fusions and lordoscoliosis. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

A

B Figure 11.47 (A) Left teratologic hip dislocation in a child with arthrogryposis. (B) Seven years after open reduction, the left hip remains well reduced. (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, CA.)


Unless they are severely contracted, m ost ch ildren sh ould have open reductions perform ed for unilateral dislocations. Th e m anagem en t of bilateral dislocation s, however, is con troversial; som e authors prefer not to do surgery because of the risks of stiffn ess and osteonecrosis, whereas oth ers routin ely perform bilateral open reduction s. Hip flexion contractures greater than 30 to 40 degrees warrant soft tissue release; abduction con tractures can be treated by release of th e iliotibial ban d with or with out varus producing fem oral osteotomy. Knee flexion con tractures greater than 20 degrees adversely impact a child’s am bulatory ability. Most can be m anaged with som e com bin ation of posterior soft tissue release, fem oral sh orten in g, an d/ or distal fem oral exten sion osteotomy. This latter procedure is extrem ely effective initially but carries a high recurrence risk as the distal fem ur ten ds to rem odel back in to flexion . Certain auth ors prefer gradual correction of kn ee deform ities by usin g circular extern al fixators. Several foot deform ities can be seen in arth rogryposis, including calcan eovalgus feet or, m ore com m only, talipes equin ovarus (clubfoot). Arth rogrypotic clubfeet are often extrem ely rigid. Serial m an ipulation an d castin g is occasionally successful, but m ost patients require radical posterom edial release aroun d th e age th at th e ch ild begin s to walk. Sim ilarly, the treatm ent of the arthrogrypotic vertical talus is m ore often surgical, consisting of open release, reduction of th e talon avicular join t, an d pin fixation . In salvage cases of both clubfoot and vertical talus, a talectomy m ay be necessary. Upper extrem ity surgery sh ould be perform ed to im prove self-care, im prove self-feedin g, an d allow computer use. In th e past, it was th ough t th at on e arm in full exten sion and one in flexion was best for function. Sin ce grip stren gth is lim ited in both hands, m ost authors n ow prefer position in g both lim bs to allow bim an ual fun ction . Sh oulder con tractures are best treated by derotation osteotom ies of th e h um erus. Passive elbow m otion can be im proved by posterior elbow release and triceps lengthening. Active elbow flexion can som etim es be improved by pectoralis, latissim us, or triceps tran sfer. Wrist flexion deform ities are typically treated by proxim al row carpectomy, dorsal wedge osteotom ies of th e m idcarpus, or wrist fusion . Th en ar release an d hand orthoses are used to treat thum b-in-palm deform ities.

METABOLIC AND ENDOCRINE DISORDERS Rickets Pathophysiology Rickets is a syndrom e rather than a specific disease en tity. Regardless of the specific etiology, the un derlying cause of th e disorder is th e lack of available calcium , ph osph o-

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rus, or both, ultim ately resultin g in the failure of bone an d cartilage to m ineralize appropriately. The effect of this im paired m in eralization is m ost ch aracteristically seen in th e physis. Calcium is typically in corporated at th e level of th e zon e of provision al calcification . Because of th e lack of calcium , this zone is all but absent but the preceding zone of hypertrophy becom es en larged an d grossly distorted from “back-up’’of th e unm ineralized physis. Along the trabeculae, osteoblastic activity is n orm al, so osteoid con tin ues to be produced at a n orm al rate. Th e lack of n orm al m in eralization , h owever, preven ts osteoclastic m ediated reorgan ization of th is osteoid. As a result, th e am oun t of osteoid builds up an d rem ain s disorgan ized, causin g widen in g of the osteoid seam s. Norm ally, calcium m etabolism is regulated prim arily by vitam in D an d parathyroid h orm on e (PTH) (Fig. 11.48). PTH is produced in th e parathyroid glan ds in respon se to a drop in serum calcium or ph osph ate. In creasin g PTH levels cause a release of calcium an d ph osph ate from bon e (wh ere th e vast m ajority of calcium is stored in th e body) an d in creased calcium reabsorption in th e kidn ey. Vitam in D production is stim ulated by exposure to sun ligh t an d th e in active form , 25-hydroxyvitam in D, is stored in the liver. Increasing PTH level also stim ulates the activation of 25-hydroxyvitam in D to 1,25-dihydroxyvitam in D in th e kidn ey. Activated vitam in D, in turn , stim ulates in creased absorption of calcium in the gastrointestinal tract an d th e proxim al tubule of th e kidn ey. Any abn orm ality in th is complex system th at decreases serum calcium or ph osph ate levels can lead to rickets.

Classification Rickets is classified on the basis of the specific etiology. Nutritional rickets (vitam in D –deficien t rickets) is th e m ost classic form of th e disease. Alth ough rare in th e developed world due to th e fortification of m ilk products, n utritional rickets can still occur in those who are exclusively breast-fed an d are sh eltered from sun exposure. Vitam in D – depen den t rickets h as two form s: type I an d type II. Type I disease is caused by a deficien cy in α-hydroxylase, the enzym e th at con verts th e in active form of vitam in D to th e active form in the kidney. Type II disease results from a defect in the intracellular receptor for active vitam in D. The m ost com m on form of rickets is vitam in D –resistan t rickets, also known as familial hypophosphatemicrickets. Th is X-lin ked disorder causes im paired ren al tubular reabsorption of ph osph ate. Oth er causes of rickets or rickets-type con dition s include renal osteodystrophy (osteom alacia from renal disease), hypoparathyroidism (low production of PTH), an d pseudohypoparathyroidism (lack of effect of PTH at th e target cells). Presentation and Physical Examination Children with rickets have generalized m uscular weakness, lethargy, and irritability. Motor developm ental m ilestones such as sittin g and walking m ay be delayed. Th e child

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Ca2+

Ca2+

Ca2+ Ca2+

Ca2+

Ca2+ Ca2+

A Figure 11.48 The roles of the bone,

Ca2+ Ca2+ Ca2+ Ca2+

1,25 (OH) vitamin D

B

Ca2+ Ca2+

Ca2+

Ca2+ Ca2+

Ca2+

Ca2+

Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+

24,25 (OH) vitamin D

C

usually h as sh ort stature. Cran ial features in clude fron tal bossin g an d den tal caries. Trun cal abn orm alities in clude en largem en t of th e costal cartilages (rach itic rosary), in den tation of th e lower ribs wh ere th e diaph ragm in serts (Harrison groove), pectus carinatum , and lon g thoracic kyph osis. Th e lower extrem ity lon g bon es are deform ed, sh orten ed,

kidneys, gastrointestinal tract, parathyroid gland, and thyroid gland in calcium kinetics. These organs act to maintain calcium in the extracellular fluid (ECF) at the appropriate levels for normal cellular function. Vitamin D and parathyroid hormone (PTH) act to transport calcium ions across the gut wall and regulate renal excretion, and thereby, bone calcium content. Depending on the need for increased transport, 25hydroxyvitamin D is converted to 24,25- or 1,25-dihydroxyvitamin D. (A) In the normocalcemic state, an equilibrium between calcium intake and excretion is maintained by the various organs. (B) In the hypocalcemic state, a reduced concentration of calcium signals the parathyroid glands to release more PTH, which acts at the levels of the gut cell, renal tubule, and bone to increase transport of calcium and rapidly replenish body fluids with it. An increase in PTH also favors the synthesis of 1,25-dihydroxyvitamin D in the kidney and acts to promote renal phosphate excretion by markedly diminishing the tubular reabsorption of phosphate. (C) In the hypercalcemic state, low concentrations of calcium and PTH act independently to diminish the synthesis of 1,25-dihydroxyvitamin D and decrease transport of calcium in the gut cell, tubule, and bone. Increased concentrations of calcium also cause the release of calcitonin (CT) from the C-cells of the thyroid gland, thereby diminishing calcium concentration. This mechanism principally involves stabilizing the osteoclast and decreasing its action on the bone, but it is not very effective in humans. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

and often bowed. Knee deform ity is very com m on and can m anifest as either genu varum or genu valgum . If rickets is active during the n orm al age of physiologic genu varum (ages 1 –2 years), th en path ologic gen u varum deform ity prevails. On th e oth er h an d, if rickets is active durin g th e n orm al age of physiologic gen u valgum (ages 2 –4 years),


Figure 11.49 Renal osteodystrophy in a 12-year-old boy. An

anteroposterior pelvis radiograph reveals an early slipped capital femoral epiphysis (SCFE) on the right. SCFE is common in renal osteodystrophy but rare in rickets. For more information on this condition, refer to the section on slipped capital femoral epiphysis. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

then genu valgum deform ity prevails. Ligam entous laxity an d fractures are com m on findings. The upper extrem ities dem on strate apparen t en largem en ts of th e join ts, as in th e lower extrem ity, but are otherwise gen erally spared. In renal osteodystrophy, the additional fin dings of pain ful periarticular calcification s an d slipped epiphyses, especially SCFE, m ay occur (Fig. 11.49).

Radiographs Th e radiograph ic fin din gs in rickets m irror th e h istologic changes (Fig. 11.50). The cortices of long bones are thin, and the trabeculae are indistinct. Osteopenia is th e hallm ark of rickets in the child. Sin ce there is no zone of provision al calcification with the resultan t “pile up’’ of hypertrophic zone cells, the width of the physis is increased. Sim ilarly, the classic cupping of the m etaphysis is noted from stunting of the growth plate centrally while n orm al periph eral apposition al growth of th e perich on dral rin g con tin ues. Ren al osteodystrophy h as som e un ique radiograph ic features, in cludin g a “salt an d pepper’’ skull; th e absence of a cortical outlin e at the distal end of clavicles; and subperiosteal resorption of the ulnas, term in al tufts of th e distal ph alan ges, an d m edial proxim al tibia. In lon gstan ding ren al osteodystrophy, brown tum ors, seen as expan ded destructive bon e lesion s, m ay appear. Special Tests Th e m ain diagn ostic tests in clude serum calcium , ph osph ate, alkalin e ph osph atase, an d PTH levels. Oth er laboratory tests include vitam in D, urine calcium , and urine phosph ate levels. Based on th e salien t laboratory fin din gs, th e un derlyin g etiology of rickets can be iden tified (Table 11.1). Differential Diagnosis Osteom alacia is the adult counterpart to rickets an d occurs on ly after th e physes h ave closed. Physiologic gen u varum , Bloun t disease, and idiopath ic gen u valgum sh ould be considered in th e differential diagn osis of genu varum and

TABLE 11.1 RICKETS Etiology

Primary Effects

Secondary Effects

Nutritional rickets ■ Vitamin D deficiency ■ Calcium deficiency ■ Phosphate deficiency

↓ 25-Hydroxyvitamin D ↓ Calcium in diet ↓ Phosphate

↓ 1,25-Dihydroxyvitamin D, ↑ PTH ↑ Vitamin D, ↑ PTH ↑ ↑ ↑ 1,25-Dihydroxyvitamin D, normal PTH

↓ ↓ ↓ 1,25-Dihydroxyvitamin D ↑ ↑ ↑ ↑ 1,25-Dihydroxyvitamin D

Normal or ↑ 25-hydroxyvitamin D Normal or ↑ 25-hydroxyvitamin D

↓ ↓ ↓ Phosphate

Other laboratory tests are normal except ↑ alkaline phosphatase

Chronically ↑ ↑ ↑ PTH Aluminum results in ↓ PTH

↑ ↑ ↑ Phosphate, ↓ calcium

Vitamin D–dependent rickets ■ Type I (α-hydroxylase deficiency) ■ Type II (vitamin D receptor defect) Hypophosphatemic rickets Renal osteodystrophy ■ High turnover ■ Low turnover

Parathyroid disorders ■ Hypoparathyroidism ↓ ↓ ↓ PTH ■ Pseudohypoparathyroidism Normal to ↑ PTH PTH, parathyroid hormone.

263

↓ 1,25-Dihydroxyvitamin D ↓ 1,25-Dihydroxyvitamin D

264


A

B

C

D Figure 11.50 Rickets. Change caused by rickets can be seen (A) at the wrist and (B) at the knees of this 1-year-old child with familial hypophosphatemic rickets. The growth plates are widened and the metaphyses are cupped, particularly at the ulna and femur. At 4 years of age (C and D) the changes have resolved with medical treatment. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

gen u valgum , respectively. O th er causes of sh ort stature, such as skeletal dysplasias, should also be con sidered in the differential diagnosis of rickets.

Treatment Medical m an agem en t of th e un derlyin g m etabolic disturban ce, usually coordin ated by a pediatric en docrin ologist, is th e m ain stay of treatm en t. Depen din g on th e specific cause of th e rickets, treatm ent m ay include adm in istration of supplem en tal vitam in D, calcium , an d/ or ph osph ate. Th e exten t of rem odelin g likely to occur depen ds on th e am oun t of growth rem ain in g after correction of th e un derlyin g m etabolic disturban ce. Ren al osteodystrophy in volves com plex m an agem en t of th e kidn ey, usually by a pediatric n eph rologist. In som e patien ts, aggressive m an agem en t of ren al fun ction m ay abrogate th e n eed for surgi-

cal in terven tion for deform ity correction an d even proxim al fem oral physeal abn orm alities. Orthopaedic intervention is required for fracture m anagem ent an d deform ity con trol. Fractures are treated with standard m ethods of closed treatm ent and open reduction/ internal fixation. Initial m an agem ent of lower lim b deform ities includes brace m anagem ent. Patients with ren al osteodystrophy, h owever, are often recalcitran t to brace m anagem ent. Patients with lower lim b deform ities that adversely affect function m ay be candidates for surgical intervention. Guided growth tech niques or realignm en t osteotom ies with in tern al or extern al fixation m eth ods can be utilized to correct align m en t an d restore an adequate m echan ical axis. Healin g tim e m ay be prolonged and recurren ce is com m on , especially in patien ts with persisten t m etabolic derangem ent. Displaced or symptom atic slipped


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TABLE 11.2

CLASSIFICATION OF OSTEOGENESIS IMPERFECTA Type

Skeletal Manifestation

Sclerae

Teeth

Collagen Defect

I

Mild

Blue

II

Lethal

Normal (IA) or dentinogenesis imperfecta (IB)

III IV

Severe Moderate

White White

Dentinogenesis imperfecta Normal (IVA) or dentinogenesis imperfecta (IVB)

Quantitative deficiency but normal collagen Abnormal collagen or severe quantitative deficiency Abnormal collagen Abnormal collagen

From Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.

capital fem oral epiphyses should be fixed with partially threaded screws.

Osteogenesis Imperfecta Pathophysiology Osteogen esis imperfecta (O I), or brittle bone disease, is a rare con dition , with an estim ated prevalen ce of 1 in 20,000 ch ildren . OI is not a single disorder but is rather a spectrum of clin ical con dition s th at h ave in creased bon e fragility in com m on. In alm ost all cases, OI results from a quan titative or qualitative defect in type I collagen form ation . Type I collagen is th e m ajor structural protein foun d in bon e, skin , ten don , ligam en t, corn ea, sclera, an d den tin , an d deficien cy in th is type of collagen results in fragility of th e en tire skeleton . Th e m ost com m on m utation s responsible for OI in volve one of two gen es th at encode th e ch ains of type I collagen , the COL1A1 gene or the COL1A2 gen e.

in th ese patien ts. Bowin g of th e lon g bon es often develops due to m icrofractures occurrin g over tim e (Fig. 11.51). The frequency of fracture declines sharply after adolescence. In addition to th e in creased fracture risk, ch ildren m ay exh ibit increased ligam en tous laxity, join t hyperm obility, and spin al deform ity (in cluding m arked kyphoscoliosis). Abn orm al collagen in the eyes m ay cause th e classic blue or gray sclerae associated with som e form s of OI. Cran iofacial

Classification Th e m ost com m on ly used classification system for categorizing OI is the Sillence classification (Table 11.2). Although the Sillen ce system accounts for the m ajority of patien ts, recen t gen etic an d bioch em ical research h as led to th e discovery of four addition al types of O I. Type V disease is ch aracterized by excessive callus form ation , wh ich can occasionally be confused with osteosarcom a. Type VI is sim ilar to types III and IV but have norm al collagen form ation. Type VII is a rh izom elic variant with a predisposition to th e proxim al appen dicular bon es. Presentation and Physical Examination Th e clin ical picture varies accordin g to th e severity an d type of OI. Multiple path ologic fractures are th e hallm ark of th e disease. In gen eral, th e earlier th e fractures occur, the m ore severe the disease. The lower lim bs are m ore frequen tly in volved as th ey are m ore pron e to traum a. Repetitive fractures in th e epiphysis or physis m ay lim it growth an d contribute to th e short stature that is com m only seen

Figure 11.51 Osteogenesis imperfecta type III. Multiple frac-

tures have created significant bowing in all four extremities. (Reproduced with permission from Broughton NS. Textbook of Paediatric Orthopaedics. London, England: WB Saunders, 1997.)

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fin din gs in clude sm all, trian gular faces; defective den tin ogen esis (sm all, fragile teeth ); an d defective h earin g from otosclerosis. Cran ial n erve palsies, h eadach es, apn eic episodes, spasticity, nystagm us, or weakn ess sh ould alert the physician to the potential for basilar invagin ation in patien ts with O I.

Radiographs Gen eralized osteopen ia is detected on plain radiograph s in patien ts with O I. Sin ce in tram em bran ous bon e growth is aberran t, th e n orm al cylin derization of lon g bon es does not occur, leaving behind th in, sten otic diaphyses as th e hallm ark of OI. The long bones appear bowed with th in cortices (Fig. 11.52). Deform ities are presen t from m ultiple fractures (Fig. 11.53). The pelvis m ay show acetabular protrusion . Th e spin e dem on strates osteopen ic vertebrae th at fracture easily, resulting in flattened or bicon cave sh ape. Th oracic or th oracolum bar scoliosis is n ot un com m on . In addition , th e skull m an ifests worm ian bon es, isolated lakes of bon e typically foun d in an d aroun d th e cran ial sutures. Figure 11.52 Multiple microfractures over time have led to bow-

Special Tests In spite of gen etic advan ces, th ere is n o sin gle test th at is sufficien t to m ake the diagnosis of OI. This is in part due to th e wide variety of gen etic an d bioch em ical con dition s that can presen t with a sim ilar phenotype. The diagn osis of OI, th erefore, rem ain s a clin ical on e based on th e en tire clinical picture in cluding the appearance of the patient, a history of fractures, th e presence of abn orm al sclerae or teeth , an d ch aracteristic radiograph ic fin din gs.

ing and coxa vara of the right femur in this child with osteogenesis imperfecta. This patient presented with hip pain and a femoral neck fracture, caused, in part, by the proximal femoral deformity.

In certain cases, pren atal diagn osis of OI can be accom plish ed by ultrasoun d wh en lon g bon e deform ity, severely reduced fem oral len gth , an d decreased ech ogen icity of th e skull are recogn ized. Quantitative abnorm alities in collagen production can be detected in 87% of patien ts with collagen an alysis of skin biopsies an d fibroblast cultures.

C

A,B Figure 11.53 (A and B) Anteroposterior views of the upper extremities and (C) the lower extremities in a child with osteogenesis imperfecta. Note the deformity and callus formation from multiple previous fractures. (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, CA.)


Bone densitom etry (dual-en ergy x-ray absorptiom etry) m easurem en ts sh ow a decrease in m ineralization. In ch ildren, the z score is utilized to evaluate the effect of treatment.

Differential Diagnosis Th e differen tial diagn osis of OI in cludes ch ild abuse, idiopath ic juven ile osteoporosis, an d rarely fibrous dysplasia. Th e presen ce of osteopen ia, blue sclerae, fam ily h istory of OI, an d hearing difficulties helps to distinguish OI from ch ild abuse. Mild cases of OI, however, are often extrem ely difficult to distin guish from n on acciden tal traum a. Th e diagn osis idiopath ic juven ile osteoporosis, un like OI, is usually a tran sien t, self-lim itin g ph en om en on . Fibrous dysplasia is n ot ch aracterized by th e presen ce of th in , sten otic diaphyses on radiograph s an d h as m ore localized in volvem en t than OI. Treatment Recent advances in m edical th erapy have greatly improved the m anagem ent of children with OI. By decreasing osteoclastic resorption of bon e, bisph osph on ates h ave been sh own to increase cortical bon e thickness, decrease th e inciden ce of fractures, relieve chronic bone pain, and increase the height of collapsed vertebrae in patien ts with

A,B

267

O I. Th e best ch oice of bisph osph on ates rem ain s un kn own as does th e optim al dosin g regim en . Down sides of bisph osph on ate therapy include a risk of delayed healing after osteotomy an d th e poten tial for osteon ecrosis of th e jaw. Th e adm in istration of calcium , vitam in D, an d calcitonin h ave been less successful th an bisph osph on ate treatm ent. Bon e m arrow tran splan t can be con sidered in th e m ost severe cases in youn g in fan ts. Th e goals of orth opaedic treatm en t are to m axim ize function, to prevent disability from m ultiple fractures, and to correct deform ity. Protective bracin g (e.g., KAFO s) to preven t fractures an d aid am bulation is an importan t com pon en t of th e m anagem en t of patien ts with O I. Wh en fractures do occur, th ey h eal at th e n orm al rate. Alth ough n on union s are relatively rare, th e callus th at form s is also weak, wh ich in creases th e risk of refracture. Th us, closed m an agem ent of fractures is initially employed with thoughtful avoidance of excessive im m obilization that can result in disuse osteopen ia. Wh en open m an agem en t is in dicated, load-sh arin g devices, such as in tram edullary n ails, are preferred over plates an d screws, wh ich ten d to lose purch ase in weak bon e an d cause a stress riser at th e edge of the implant. For significant deform ity, realignm ent osteotom ies with in tram edullary fixation can improve m ech an ical alignm en t and preven t recurrent fractures (Fig. 11.54).

C

Figure 11.54 Leg deformity in a patient with type III osteogenesis imperfecta. (A) Preoperative anteroposterior radiograph obtained at age 6 years demonstrates left tibial deformity. (B) Postoperative radiograph with leg in a cast shows multiple osteotomies (arrows) with intramedullary fixation. (C) Films obtained after healing of osteotomies. (Reproduced with permission from Kocher MS, Shapiro F. Osteogenesis imperfecta. J Am Acad Orthop. 1998;6:225–236.)

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Scoliosis ten ds to progress relen tlessly in patien ts with OI, regardless of brace m anagem ent, an d often requires posterior spin al fusion with in strum en tation before th e curve gets too severe. The surgeon m ust be prepared to achieve fixation in osteopenic elem ents by using a com bination of wires, h ooks, an d screws. Pseudarth rosis m ay occur in th is m ech an ically disadvan tageous en viron m en t. Finally, sym ptom atic basilar in vagin ation m ay require form al decompression and stabilization.

Osteopetrosis Pathophysiology O steopetrosis is a sclerosin g bon e dysplasia ch aracterized by a diffuse in crease in skeletal den sity an d obliteration of m arrow spaces. Th e prim ary defect is osteoclastic dysfunction that impairs the body’s ability to resorb an d rem odel bone. Histologically, th e skeleton shows cores of calcified cartilage surrounded by areas of norm al n ew bon e form ation . Alth ough th is bon e con tain s norm al to increased n um bers of osteoclasts, th e cells are abn orm al in fun ction , as dem on strated by th e absen ce of ruffled borders an d clear zon es. As a result, bon e an d cartilage can n ot be resorbed an d a den se pile of prim itive trabeculae an d calcified ch on droid accum ulates over tim e. Despite its den sity, osteopetrotic bon e is brittle an d m ore likely to fail un der stress compared with n orm al bon e. Th e in ability to rem odel bon e also leads to narrowed m edullary spaces an d im paired h em atopoietic function. Classification Th ere are th ree form s of osteopetrosis: in fan tile m align an t, in term ediate, an d adult tarda. In fan tile an d in term ediate osteopetrosis are tran sm itted as an autosom al recessive trait. Adult form is in h erited in an autosom al dom in an t pattern . Presentation and Physical Examination Ch ildren with osteopetrosis often presen t with path ologic fractures due to the fragility and brittleness of th eir bones. Bony overgrowth of th e cran ial foram ina m ay m anifest as cranial nerve palsies, blindness, or deafness. Osteomyelitis an d den tal caries are n ot un com m on because of dim in ish ed vascularity of th e bon e an d a defective im m un e response. Th e lack of sufficien t m edullary space can cause depressed bon e m arrow fun ction an d pan cytopen ia; affected patients typically present with signs and symptom s of an em ia, recurren t in fection s, abn orm al bleedin g, easy bruisin g, fatigability, an d failure to th rive in severe cases. In addition , th is m arked dim in ution of bon e m arrow results in h epatosplenom egaly as extram edullary sites of hem atopoiesis are stim ulated. For m alignan t in fantile osteopetrosis, th e clin ical course is rapidly progressive, an d death m ay occur at a youn g age from sepsis or an em ia. O n

th e oth er h an d, patien ts with th e adult form h ave a n orm al life expectancy.

Radiographs Th e h allm ark of osteopetrosis is in creased den sity of th e bon es (Fig. 11.55). Th e m arble-like osseous structures appear den sely wh ite with out m edullary cavities. Bon e with in bon e, kn own as endobone, is an area of radioden se tissue that exists inside the cortices of other bones; the presence of th is radiograph ic fin din g is path ogn om on ic of osteopetrosis. Sclerosis at th e vertebral en d plates with n orm al den sity of the cen tral body leads to a “rugger jersey’’ appearance of the spine (Fig. 11.56). In the appen dicular skeleton, the m etaphyses are abnorm ally dilated (Erlenm eyer flask appearance) because of impaired rem odeling an d tubularization of th e long bones. On skull film s, the basilar portions of the skull are sclerotic, and the supraorbital ridge is den se an d quite prom in en t. Frequen tly, altern atin g ban ds of sclerosis an d lucen cy are seen subjacen t to th e growth plate, wh ich correlates with periods of h igh an d low disease activity. Special Tests Routine blood tests are in dicated in m ost patients to screen for pancytopenia or anem ia. Pren atal diagn osis of osteopetrosis h as been accom plish ed in th e 25th week of pregn an cy with th e use of fetal radiography, wh ich reveals sclerosis of osteopetrotic bon e. Ultrasoun d h as also been used to iden tify affected fetuses. Treatment Treatm ent for infantile osteopetrosis is bone m arrow transplan tation at a youn g age. A successful tran splan t can resolve both th e skeletal and hem atologic abnorm alities. High dose 1,25-dihydroxyvitam in D th erapy with a low calcium diet has been employed because of its ability to stim ulate osteoclasts an d bone resorption. O rth opaedic treatm en t ten ds to focus on fracture care an d deform ity m anagem ent. Most fractures respond well to closed treatm en t, although healing m ay be delayed. When open treatm en t is n ecessary, th e extrem ely h ard bon e can m ake fixation difficult: broken screws, drill bits, and even drivers are a com m on experien ce. Severe deform ity m ay require corrective osteotom ies, especially coxa vara of th e h ip. Sim ilar to th e treatm en t of fractures, surgery is tech n ically ch allenging due to the difficulty in m aking the osteotomy an d achieving adequate fixation.

Scurvy Th is n utrition al defect is a classic bon e dystrophy th at largely affects the m etaphyseal region. The extrin sic defect is a deficiency in vitam in C, which is a cofactor in the norm al pathway of bone collagen synthesis. In its absence, th e resulting collagen is poorly cross-linked and

A

B

C

D

E

Figure 11.55 Six-month-old male infant with severe osteopetrosis and pancytopenia. (A–E) Dense

sclerotic bones at the pelvis (A), humerus (B), and forearm (C), without evident medullary cavities. (D and E) After successful bone marrow transplantation, the bony architecture in the humerus (D) and the forearm (E) were normalized. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

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logic or pathologic. In general, growth is considered aberran t wh en it falls two stan dard deviation s below th e m ean h eight for age. Arguably, th is will in clude som e n orm al individuals; however, it should stim ulate the exam iner to m ore carefully pursue a diagnosis before assum ing that th e child is “physiologically short.’’ The pathologic causes of sh ort stature are m any but include both skeletal dysplasias and m ucopolysacch aridoses (MPSs). An accurate diagnosis m ust be establish ed to provide appropriate m edical care for these patien ts and to provide genetic counseling to the patien t an d fam ily.

Achondroplasia Pathophysiology Achondroplasia is the m ost com m on type of skeletal dysplasia, with an estim ated worldwide prevalen ce of 1 in 15,000 to 40,000 live births. It can be inherited in an autosom al dom inant fashion, alth ough as m any as twothirds of cases arise from spontaneous m utations. The defect in ach ondroplasia is an activatin g m issense m utation in the gene encoding fibroblast growth factor receptor-3 (FGFR-3), m apped to chrom osom e 4. Th e m utated gene product ultim ately results in retardation of cell division in the proliferative zon e of the physis, thereby lim iting ench ondral bone growth. Intram em branous bone growth is n ot affected.

Figure 11.56 The classic rugger jersey appearance of the spine

is seen in this 15-year-old girl with osteopetrosis. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

m ech an ically deficien t. Not surprisin gly, th e clin ical state m irrors th is deficien cy in collagen . “Slippin g’’ of th e epiphyseal plates with m in im al, if any, traum a is a h allm ark of th e disease. With physeal displacem en t, h em orrh age occurs un der the periosteum . This results in stripping of th e adjacen t m etaphyseal periosteum an d subsequen t subperiosteal bone form ation . The petechial hem orrhages seen in th ese ch ildren are due to th e defect in collagen located in th e basem en t m em bran e of skin . Vitam in C supplem en tation is gen erally sufficien t to cure th is con dition .

SHORT STATURE AND SKELETAL DYSPLASIAS Not in frequen tly, ch ildren are referred to an orth opaedic surgeon for an evaluation of sh ort stature. It is initially im portan t to determ in e wh eth er th e sh ort stature is physio-

History and Physical Examination In th e workup of ach on droplasia, as with all skeletal dysplasias, a fam ily h istory of sh ort stature or skeletal dysplasia should be sought. A history of m ental retardation tends to m ove th e diagn ostic emph asis toward ch rom osom al defects rath er than true skeletal dysplasias since dysplasias are rarely associated with cogn itive deficits. Physical exam in ation can yield a great deal of inform ation and is extrem ely h elpful for distinguishin g ach on droplasia from physiologic short stature an d other skeletal dysplasias. Standing an d sitting height should be m easured over tim e and percen tiles should be determ ined from standard charts. Head circum feren ce sh ould also be noted but is often preserved in achondroplasia since th e skull enlarges by intram em bran ous ossification . Th e proportion ality of trun k len gth to lim b len gth sh ould be assessed; ach on droplasia, like m ost skeletal dysplasias, exhibits disproportionate sh ort stature. The pattern of lim b shortening sh ould also be evaluated. Certain skeletal dysplasias in cludin g ach on droplasia h ave sh orten ing prim arily of th e proxim al segm en t of the lim bs (arm s and th igh s). This is term ed rhizomelic shortening. When the m iddle segm ent of the lim b (forearm and leg) is short, this is called mesomelic shortening. If th e distal segm en ts (h an d an d feet) dem onstrate the sh ortenin g, this is referred to as acromelic shortening. In addition to th e overall exam in ation of h eigh t an d proportion ality, specific region s of th e body sh ould be


exam in ed in patien ts with ach on droplasia. Bowin g at th e knees or tibia is com m on and an accurate assessm ent of lower lim b alignm ent sh ould be perform ed at each office visit. A careful n eurologic exam ination is warranted in all patien ts with ach on droplasia because of th e h igh in ciden ce of spin al sten osis.

Presentation In fan ts presen t soon after birth with a ch aracteristic appearan ce (Fig. 11.57). The skull is norm al in size but appears large relative to the shortened skeleton ; frontal bossing and m idface hypoplasia are typical. Trun k length is within the lower range of n orm al, but the lim bs are significantly sh orten ed in a rh izom elic pattern . Likewise, th e ribs are also sh ort, causing the chest wall to be sm all and constricted. Th is results in th e appearan ce of a protuberan t abdom en . Th oracolum bar kyph osis is com m on but can improve with age. Compensatory hyperlordosis in the lum bar region fre-

A

B

Figure 11.57 A 16-year-old boy with achondroplasia. (A) Pro-

nounced shortening of the proximal limb segments (rhizomelic pattern). There is mild genu varum. The humeri are most affected. (B) The elbows have a mild flexion contractures. He has had previous osteotomies of the tibias and fibulas for genu varum. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

271

quen tly occurs. Scoliosis is seen in on e-th ird of th ese patients but is usually m ild. Most patients with achon droplasia have som e degree of spin al sten osis from shortened pedicles and a decreased interpedicular distan ce. Som e patien ts m ay present with exercise in toleran ce an d early fatigability; in severe cases, frank myelopathy or radiculopathy can occur. The upper extrem ities typically dem on strate extra space between th e th ird an d fourth rays of th e h an ds, causin g a “triden t h an d’’ appearan ce. Th e lower extrem ities often exhibit in creased ligam en tous laxity, gen u varum , an d in tern al tibial torsion. Developm en tal m ileston es m ay be in itially delayed, but n orm al m otor coordination even tually develops. Independen t am bulation is typically achieved by 18 to 24 m onths of age. Ach on droplasia, like oth er skeletal dysplasias, is typically associated with norm al intelligen ce. Life expectancy is som ewh at dim in ished, but quality-of-life studies h ave sh own sim ilar scores compared with the general population.

Radiographs All patien ts wh o are suspected of h avin g ach on droplasia or any oth er type of skeletal dysplasia sh ould receive a skeletal survey. Th is in cludes a lateral radiograph of the skull an d n eck an d AP views of the entire spine, pelvis, arm s, hands, and legs. The radiograph ic changes seen in achondroplasia reflect those region s that are m ost dependen t on en ch on dral ossification . In th e lon g bon es, th e m etaphyses are flared and the diaphyses are thick from appositional growth. Unlike other types of skeletal dysplasia, th e epiphyses are spared. Lower extrem ity radiographs m ay dem onstrate genu varum from abnorm alities of th e distal fem ur, proxim al tibia, or relative overgrowth of th e fibula. The radiographic appearan ce of the pelvis is classic in ach on droplasia. Since the h eigh t of the pelvis is a function of enchondral bone growth, the achondroplastic pelvis is un derdeveloped an d flatten ed with a “ch am pagn e glass’’outlet, sm all sciatic notches and squared iliac wings. At th e h ip, th e proxim al fem oral m etaphyses are widen ed and the fem oral necks are short. Spin e radiograph s are n ecessary to screen for scoliosis and kyphosis. In the latter condition , the apical vertebrae m ay becom e progressively wedge-shaped in the sagittal plan e. Th e AP view sh ould also be evaluated for decreasing interpedicular distance, which indicates the presence of spin al stenosis (Fig. 11.58). Special Tests Direct deoxyribon ucleic acid an alysis to iden tify m utation s in th e FGFR3 gen e can be perform ed postn atally or pren atally to screen fam ilies at risk. In addition , pren atal ultrason ography can iden tify characteristic skeletal anom alies and hydrocephalus. Advanced im aging studies, either CT

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velops, resulting in an apparent short trunk. The head an d face are usually n orm al, an d th ere is often a sm all, tail-like appendage overlyin g the lower sacrum . Chondroectoderm al dysplasia is a short-lim bed dwarfism but is also characterized by postaxial polydactyly; abn orm alities of th e n ail, h air, an d teeth ; an d con gen ital h eart failure. Patien ts with chon drodysplasia pun ctata present with m ultiple punctate epiphyseal calcification s at birth , but th ese resolve over th e first year of life. Children later have joint contractures, coxa vara, atlantoaxial instability, and congen ital kyphoscoliosis, in addition to proxim al lim b shortening. Pseudoachon droplasia in volves both th e epiphyses an d m etaphyses of long bon es. The head and face are norm al, an d hip dysplasia an d prem ature osteoarth ritis are com m on.

Figure 11.58 This anteroposterior view of the entire spine

shows the progressive narrowing of the interpedicular distance at more caudal levels of the lumbar spine; this is the opposite of the normal pattern and suggests spinal stenosis. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

or MRI, m ay be n ecessary to evaluate for foram en m agnum sten osis, which is com m on due to th e disproportion ate growth of th e calvarium relative to th e basilar skull an d neck. MRI is also useful in the workup of spinal stenosis to localize areas of cen tral or foram in al compression .

Differential Diagnosis Th e differen tial diagn osis of ach on droplasia in cludes oth er causes of short stature such as rickets and other types of skeletal dysplasia. Many differen t skeletal dysplasias have been described, an d a com plete discussion of all of these conditions is beyond th e scope of th is text. Som e brief differen ces will be m en tion ed an d select con dition s (diastroph ic dysplasia, spon dyloepiphyseal dysplasia [SED], and m ultiple epiphyseal dysplasia) will be discussed in the following section. Short-lim bed dysplasias in clude hypoch on droplasia, m etatropic dysplasia, ch on droectoderm al dysplasia (also kn own as Ellis–van Creveld syn drom e), diastroph ic dysplasia, chon drodysplasia pun ctata, an d pseudoach on droplasia. Hypoch on droplasia resem bles achondroplasia but is less severe. In m etatropic dysplasia, th e in fan t ch ild h as sh ort lim bs an d a relatively lon g trun k, but as th e ch ild grows, severe kyph oscoliosis de-

Treatment From a m edical stan dpoin t, in fan ts with ach on droplasia sh ould be carefully m on itored during the first few years of life for sleep apnea, spasticity, or hypertonia, wh ich m ay be th e result of foram en m agn um sten osis. Alth ough th is gen erally im proves with growth , severe cases m ay warran t decom pression of th e brain stem . Ear, n ose, an d th roat problem s are frequen t because of m idface hypoplasia, an d early referral to an otorh in olaryn gologist m ay be in dicated. From an orth opaedic stan dpoin t, treatm en t is gen erally aim ed at controlling deform ity, m axim izing function , and preven tin g n eurologic deterioration . Gen u varum is typically m an aged by corrective osteotomy since there is no eviden ce th at bracin g is effective in ch ildren with ach on droplasia (Fig. 11.59). Hip deform ities should be corrected surgically to preserve a n eutral m echanical axis an d m axim ize function. The thoracolum bar kyphosis seen in in fan ts with ach on droplasia sh ould in itially be observed. In m ost cases, th e deform ity resolves as the child begins to am bulate and m uscle tone improves (Fig. 11.60). In th e 10% to 15% of cases that do n ot resolve, bracing m ay be used for flexible curves. Occasion ally, posterior fusion and instrum en tation m ay be necessary to correct persistent deform ity. Spin al sten osis sh ould be treated with wide decom pression (several levels above the stenotic segm ent to several levels below) followed by posterior stabilization . Th e use of pedicle screws is preferred over wires or hooks, which occupy space in th e already n arrowed spinal can al. Th e topic of lim b len gth en in g is a source of sign ifican t con troversy in the orthopaedic com m unity. Quality-of-life studies in patients with achondroplasia have dem onstrated excellen t fun ction , an d critics complain th at lim b len gth en in g is a lon g an d difficult process to un dertake for prim arily a cosm etic result. Proponen ts of len gthenin g cite the ability to improve self-im age and enhance function in an otherwise adult-sized world. Unlike m ost other types of skeletal dysplasia, achon droplasia is am enable to len gthen in g because th e join ts are n orm al an d th e ten don s, vessels, and nerves h ave a capacity to stretch . The decision to


A,B

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C,D Figure 11.59 (A) This 9-year-old boy with achondroplasia has genu varum frequently seen in this

condition. (B) Standing anteroposterior (AP) radiograph of the lower extremities confirms genu varum due to fibulae being longer than the tibiae. (C) Standing AP radiograph of the lower extremities following corrective tibial and fibular osteotomies demonstrates reestablishment of a normal mechanical axis. (D) Postoperative clinical photograph confirms improvement in genu varum. (Reproduced with permission from Skaggs DL, Flynn JM: Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

A,B

C Figure 11.60 Thoracolumbar kyphosis in a 23-month-old achondroplastic child who has not walked

yet. (A) It is most pronounced in the sitting position. (B) Radiograph shows hypoplasia of L1, with rounding-off of the anterior vertebral body corners. (C) At 5 years of age, after a period of brace treatment, the shape of L1, as well as the overall kyphosis has improved. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

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un dergo lim b len gth en in g, h owever, sh ould be m ade on ly after fran k an d open discussion s h ave been h eld regardin g th e len gth of treatm en t (often 2 years), th e poten tial complications, an d the personal m otivation of the patient. If un dertaken , gradual correction with distraction osteogen esis an d extern al fixation is th e m eth od of ch oice. Often , several courses of len gth en in g in both th e upper an d lower extrem ities are n ecessary to improve proportion ality of th e skeleton . An gular deform ity, join t stiffn ess, an d neurovascular injury are possible complications from lim blen gth en in g procedures.

MISCELLANEOUS SKELETAL DYSPLASIAS As m entioned, m any different skeletal dysplasias exist, and a complete discussion of all of these condition s is beyon d the scope of this text. Afew select conditions includin g diastroph ic dysplasia, SED, an d m ultiple epiphyseal dysplasia will be discussed.

Diastrophic Dysplasia Diastroph ic dysplasia is a severe sh ort-lim bed dwarfism that is extrem ely rare, affecting approxim ately 1 in 100,000 live birth s. Diastroph ic dysplasia is in h erited in an autosom al recessive fash ion an d in volves th e gen e DTDST, wh ich en codes a sulfate tran sporter protein th at is in volved in proteoglycan m etabolism in cartilage. As a result, cells in affected cartilage h ave an impaired growth respon se to fibroblast growth factor. Ultim ately, en ch on dral growth is impaired. Diastroph ic dysplasia is quite apparen t at birth , n oted by extrem ely short stature, rhizom elic sh ortening of the lim bs, and rigid foot deform ities (Fig. 11.61). Th e head is n orm al-sized but th e face is dysm orph ic with a n arrow nasal bridge, flared nostrils, and a broad m idn ose. Prom inent cheeks an d fullness around the m outh have som etim es led to th e term “ch erub dwarf.’’ At approxim ately 3 to 6 weeks of age, the external part of the ear develops cystic swellin g th at later calcifies in florets, resultin g in th e ch aracteristic “cauliflower ear.’’ Th e h an ds are typically sh ort and broad with ulnar deviation. Abduction and sh orten ing of the first m etacarpal leads to the ch aracteristic appearan ce of a “h itch h iker th um b.’’ Flexion con tractures often develop at th e elbow, h ip, an d kn ee join ts, resultin g in severe fun ction al lim itation an d gait disturban ce. Hip dysplasia or fran k dislocation is a com m on fin din g; bilateral dislocation s are seen in up to 25% of cases. Un like ach on droplasia, th e epiphyses in diastroph ic dysplasia are affected an d m ay becom e flatten ed an d arth ritic over tim e. At the knees, genu valgum frequently occurs and m ay be associated with patellar dislocation . A wide spectrum of foot deform ities is seen in patients with diastrophic dysplasia. Th e m ost com m on fin din gs in clude adduction an d valgus or clubfoot. There m ay be a wider space between

Figure 11.61 A 5-year-old girl with diastrophic dysplasia. Note

the prominent cheeks, circumoral fullness, equinovarus feet, valgus knees with flexion contractures, and abducted or “hitchhiker” thumbs. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

the great toe and the second toe, resultin g in a “hitchhiker toe’’ appearan ce. Th ese deform ities are often rigid an d recalcitrant to stretching casts. The cervical spine is kyphotic in 30% to 50% of patients. Som e of th ese deform ities resolve spontan eously, whereas others progress. Scoliosis of the thoracolum bar spine can be seen in up to a th ird of patients. Curves m ay be idiopathic-like or sharply an gulated with con com itan t kyph osis. Un like ach on droplasia, spin al stenosis occurs in frequen tly. Pren atal diagn osis m ay be suggested on th e basis of th e ultrason ograph ic iden tification of classic fin din gs such as sh ort lim bs, “h itchh iker thum bs,’’ and foot deform ities. Pren atal diagn osis is also available durin g th e first trim ester by m utation analysis of ch orion ic villous DNA. Postnatally, radiograph ic evaluation sh ould in clude a com plete skeletal series (as in all skeletal dysplasias). In particular, patients with diastroph ic dysplasia sh ould h ave serial lateral radiograph s of th e cervical spin e to diagn ose an d m on itor any existin g cervical kyph osis or in stability. Th e m an agem en t of ch ildren with diastroph ic dysplasia focuses on each of th e affected regions. Cervical kyph osis often improves with growth ; therefore, close observation is initially indicated for all children except those with


A

275

B Figure 11.62 (A) Cervical kyphosis in a 1-year-old child with diastrophic dysplasia and marked deformity of C4. The patient was neurologically normal. (B) Seven years later, the vertebral bodies have been restored to a nearly normal shape without any intervention. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

neurologic impairm ent (Fig. 11.62). Progressive, symptom atic, or un stable deform ities require cervical decom pression an d fusion usually followed by h alo im m obilization. Scoliosis rarely responds to bracing, and posterior fusion is recom m en ded for progressive curves greater th an 50 degrees. Deform ed h ips m ay require corrective osteotomy. In dislocated hips, closed reduction is seldom successful an d open reduction with pelvic an d/ or fem oral osteotom ies an d soft tissue releases is usually necessary to achieve adequate reduction . Despite on e’s best efforts, h ips in diastrophic dysplasia often develop early osteoarthritis and m ay require joint arthroplasty in adulthood. Foot deform ities are often rigid in diastroph ic dysplasia, and thus are resistance to stretching casts. Surgical correction to ach ieve a plan tigrade foot is often n ecessary on ce th e ch ild’s foot h as reach ed an operable size. Surgical recon struction in cludes appropriate osteotom ies and soft tissue releases catered to the individual foot. Postoperative bracing is recom m ended. Recurrence is com m on, often necessitating repeat surgery. Severe deform ities m ay warran t salvage procedures such as talectom y or fusion .

Multiple Epiphyseal Dysplasia As the nam e implies, m ultiple epiphyseal dysplasia (MED) is a skeletal dysplasia that affects m ultiple epiphyses in the

skeleton with relative sparing of the physes and m etaphyses. MED is a h eterogen eous disorder, but in m ost cases, a m utation in the gene on chrom osom e 19 th at codes for cartilage oligom eric m atrix protein is responsible for the disorder. Patien ts with MED typically presen t later in ch ildh ood an d occasion ally as late as adulth ood. Sh ort stature is m oderate: m ost patien ts ach ieve an average adult h eigh t of between 54 an d 60 in . Presen tin g complain ts in clude join t pain , decreased ran ge of m otion , difficulty walkin g, an d an gular deform ities of th e lower extrem ity. MED affects m ultiple join ts in both lower an d upper extrem ities, but th e spin e an d face are n orm al. Th e m ost severe site of involvem en t is usually th e h ips. Coxa vara an d join t subluxation are com m on , an d coexistin g avascular n ecrosis can develop in up to 50% of patien ts; early degen erative ch an ges result from the flattened and m isshapen epiphysis. Knees generally dem on strate gen u valgus from hypoplastic fem oral condyles an d sloping of the proxim al tibia. Th e ankles are also in valgus, usually from squarin g of th e talus. In th e upper extrem ities, com m on fin din gs in clude flexion con tractures, fin ger deform ities, an d dislocation of th e radial h ead with com pensatory capitellar en largem en t. Radiograph s, in cludin g a complete skeletal series, are an essen tial part of th e diagn ostic workup. In volvem en t of m ultiple join ts is ch aracteristic, an d secon dary ossification centers are generally delayed in appearan ce. The epiphyses

276


Figure 11.63 Multiple epiphyseal dysplasia. Note the deformity

in the femoral epiphyses. Such changes can occasionally be confused with those seen in Legg–Calve–Perthes ´ disease (see hip section).

even tually appear but are sm all an d fragm en ted. Durin g skeletal m aturation, these fragm en ted region s coalesce, but the fin al shape of the epiphysis is flattened, enlarged, an d dysm orph ic. Often , an arth rogram or MRI is n ecessary to assess th e true sh ape of th e epiphysis. Abn orm al join t m orph ology predisposes patien ts with MED to early degen erative arth ritis. Th e radiograph ic appearan ce of h ips in MED can often be confused with bilateral Perthes disease (Fig. 11.63). Unlike Perthes disease, the radiograph ic fin dings in MED are usually sym m etric an d th e acetabular ch an ges m ore pron oun ced. Skeletal surveys will gen erally reveal in volvem en t of oth er join ts in MED. Treatm en t is aim ed at m an agin g deform ity an d preservin g fun ction . Durin g ch ildh ood, realign m en t procedures of th e lower extrem ity th rough guided growth or corrective osteotomy can im prove pain an d m ech an ical loadin g of th e knees and ankles. Hips that exhibit progressive subluxation or pain sh ould be recon structed with fem oral osteotom ies an d/ or acetabular procedures. Degen erative arth ritis later in life often requires total join t arth roplasty.

Spondyloepiphyseal Dysplasia SED is an extrem ely rare skeletal dysplasia occurrin g in approxim ately 1 in 4 m illion people. Th e con dition com es in two m ajor form s: con gen ita an d tarda. SED con gen ita is typically in h erited in an autosom al dom in an t fash ion , whereas SED tarda is usually X-linked. In both cases, h owever, th e con dition can arise from spon tan eous m utation or differen t pattern s of gen etic tran sm ission . Both form s of the disorder result from a genetic defect in the production of type II collagen . SED tarda presen ts at a later age with m ilder clin ical features than SED congenita. In th e latter form , patients presen t with a ch aracteristic appearan ce of sh ort stature

(in volving both trunk and extrem ities), sm all m outh, pectus carin atum , sm all rib cage, and protuberant abdom en (Fig. 11.64). Hips usually have varus deform ities and flexion con tractures that lead to a compensatory lum bar lordosis an d a waddlin g gait. Kn ees typically are in varus, and the m ost com m on foot deform ity is equinovarus. As the nam e implies, SED congenita affects the spin e in addition to th e extrem ities (un like MED). Neck in stability is com m on from odontoid hypoplasia, and a careful neurologic assessm ent is necessary in all patients to screen for myelopathy. Scoliosis is presen t in approxim ately 50% of patients. In con trast, SED tarda results in a m ildly sh orten ed stature, m ostly due to sh ortening of the trun k rather th an th e extrem ities. Spin e in volvem en t is equally m ild an d usually consists of m ild platyspondyly. Angular deform ities of th e lower extrem ity are relatively rare, but degen erative changes can occur in the hips and knees by early adulthood. A skeletal survey including appropriate views of the spin e are n ecessary as part of the diagnostic workup. Varus deform ities of th e proxim al fem ur are typical of SED con gen ita, an d ossification of th e fem oral epiphysis m ay be delayed. In both form s of SED, radiograph s of th e h ip m ay reveal flattening, enlargem ent, and progressive extrusion of th e epiphysis (Fig. 11.65). In the lower extrem ities, gen u valgum is m ore com m on th an gen u varum . Spin e radiograph s will dem on strate flatten in g of th e vertebral bodies (platyspon dyly), posterior wedgin g of th e vertebra, and disc space n arrowing. Th e pattern of scoliosis, when presen t, is sh arply an gulated over a few vertebral segm en ts. As m en tion ed, cervical views sh ould be obtain ed periodically to look for os odon toideum , odon toid hypoplasia, or atlantoaxial instability. Like other skeletal dysplasias, th e orthopaedic treatm ent of SED focuses on deform ity m an agem en t. Valgus producing osteotom ies of the proxim al fem ur are indicated for progressive varus deform ities of th e h ips. Sligh t overcorrection sh ould be the goal because of the h igh risk for recurren ce, and coexisting flexion contractures should be released under th e sam e an esth etic. Subluxation or extrusion sh ould be recon structed with fem oral an d/ or pelvic osteotom y. An gular deform ities of the lower extrem ities are best m anaged with corrective osteotomy. Clubfeet in SED are usually less stiff th an in diastrophic dysplasia; as a result, conven tion al prin ciples of serial m an ipulation an d castin g sh ould be attempted before resortin g to open release an d osteotomy. Cervical instability that exceeds 8 m m or that is symptom atic should be treated by cervical fusion along with decom pression for cases with coexistin g sten osis. Because th e cervical bon es are usually quite sm all, segm en tal fixation is difficult and halo im m obilization is usually necessary.

Mucopolysaccharidoses Although they are not prim ary bone dysplasias, MPSs are frequently included in discussions of skeletal dysplasias because th ey lead to sh ort stature.


277

Figure 11.64 Spondyloepiphy-

seal dysplasia congenita produces extreme short stature. (A) This 12year-old boy is with his 14-yearold brother. (B) Note the extreme trunk shortening, increased lumbar lordosis, and hip flexion contracture. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

A

Figure 11.65 Anteroposterior radiograph of the pelvis in a 6-

year-old boy with spondyloepiphyseal dysplasia congenita demonstrates marked coxa vara and delayed epiphyseal ossification typical of this condition. Proximal femoral valgus–extension–internal rotation osteotomy is often required for these patients. (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

B

Pathophysiology MPSs are a group of in herited m etabolic disorders caused by a deficiency of various lysosom al enzym es. Norm ally, lysosom al enzym es are in volved in glycosam inoglycan processin g an d degradation . Deficien cy of th ese en zym es results in th e accum ulation of m etabolic end products in the brain , viscera, an d m usculoskeletal tissues. Excess sugars spill over and are detectable in the urin e. Norm al physeal growth becom es disrupted wh en th ese en d products accum ulate at th e growth plate an d ch aracteristic h istologic changes in the proliferative and hypertrophic zones of th e physis can be seen . Th e overall in ciden ce of MPSs is 1 in 25,000 live birth s. Th e m ore prevalen t MPSs are tran sm itted by an autosom al recessive m ode of inheritan ce, with th e exception of Hunter syn drom e, wh ich is transm itted in an X-lin ked recessive fash ion . Morquio an d Hurler syn drom es are th e m ost com m on types of MPSs.

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TABLE 11.3

MUCOPOLYSACCHARIDOSES Syndrome

Enzyme Deficiency

Hurler

α-L-iduronidase

Hunter

Sulfo-iduronate sulfatase

Sanfilippo Morquio

Multiple enzymes Galactosamine-6-sulfatase β -galactosidase β -glucuronidase

Maroteaux–Lamy

Classification MPSs are classified by th e deficien t lysosom al en zym e an d the type of accum ulated end product (Table 11.3). Presentation and Physical Examination Th e diagn osis usually becom es clin ically apparen t between 6 m on th s an d 10 years of life, depen din g on th e type of MPS an d th e speed at wh ich th e m ucopolysacch aride accum ulates. Wh ile th ere is clin ical variability with in th is group of syn drom es, th ese disorders sh are som e com m on clin ical features (Fig. 11.66). These include facial dysm orphism , sh ort stature, hepatosplen om egaly, neurologic deficits, cardiac problem s, an d join t con tractures. Men tal retardation is associated with m ost types, as is deafn ess. Morquio syn drom e, h owever, is ch aracterized by n orm al in telligen ce. All patients with MPS h ave thick and inelastic skin with varying degrees of severity. The facial dysm orphic features include a flat nasal bridge, hypertelorism , a prom in en t foreh ead an d corn eal cloudin g. Patients typically dem onstrate short trunk dwarfism . An abn orm al gait often results from an gular deform ities of the lower extrem ities (usually genu valgum ) or join t con tractures due to deposition of m ucopolysacch arides in th e join t capsule an d periarticular tissues. O n e exception is Morquio syn drom e in wh ich patien ts usually develop gen eralized join t laxity in stead of con tracture. Hips m ay develop progressive dysplasia an d coxa valga. A careful n eurologic exam in ation is warran ted in ch ildren with MPS because of th e h igh in ciden ce of odon toid hypoplasia an d atlan toaxial in stability, especially in patien ts with Morquio syn drom e. Patien ts with ton al ch an ges are usually flaccid, n ot spastic; myelopathy can develop early, an d sudden death h as been reported. Th e rem ain der of th e spin e m ay dem on strate platyspon dyly an d kyph oscoliosis. Radiographs Just like the clinical features, the radiograph ic findings in MPS are n ot presen t at birth but develop over tim e as th e m etabolic products accum ulate. A skeletal survey, stan din g

Accumulated End Products

Mental Status

Dermatan sulfate Heparan sulfate Dermatan sulfate Heparan sulfate Heparan sulfate Keratan sulfate

Rapid deterioration

Dermatan sulfate

Variable

Variable deterioration Severe deterioration Normal

h ip to an kle radiographs, an d dyn am ic views of th e cervical spin e are gen erally in dicated in th e diagn ostic workup of any MPS. Pelvic radiograph s will often dem on strate en larged and dysplastic acetabuli and coxa valga of the proximal fem ur. The fem oral epiphysis m ay appear underdeveloped because of a sm all ossific n ucleus, but MRI or arth rogram will dem on strate a large, dysm orph ic cartilagin ous fem oral

Figure 11.66 The classic appearance of a mucopolysaccharidosis in a 3-year-old patient includes facial features that are mildly coarsened, an abdominal protuberance from an enlarged spleen and liver, a short trunk, and stiff interphalangeal joints of the fingers. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

279


head. Skull radiographs sh ow a th ick and en larged calvarium . The clavicles are broad, especially m edially an d an teriorly. On spine radiograph s, the vertebrae are som ewh at flatten ed an d “flam e-sh aped’’ with an terior-in ferior beakin g. Lateral cervical views will usually reveal odon toid hypoplasia; flexion an d exten sion views are n ecessary to screen for atlan toaxial instability (Fig. 11.67).

A

Special Tests MPS are generally diagnosed by urin e screenin g for elevated sugar levels by using a toluidin e blue-spot test. Positive tests are followed by m ore sophisticated biochem ical analyses of both urine and serum to determ ine the specific m ucopolysacch aride th at h as accum ulated. Iden tification of the m etabolic end product alone is not sufficient to

B

Figure 11.67 Characteristic radiographic features in a child with

C

Morquio syndrome including an absent odontoid (A), a pelvis with capacious acetabuli and coxa valga (B), and marked genu valgum (C). (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

280


Figure 11.68 (A) Sagittal cut of magnetic reso-

A

diagn ose MPS but sh ould be coupled with qualitative an alysis an d en zym e estim ation s for m ore defin itive diagn osis. Pren atal diagn osis for m ost of th e MPS types is available to h igh -risk m oth ers, such as th ose with an oth er affected offsprin g. Carrier status can be determ in ed by en zym atic assays in h igh -risk in dividuals.

Differential Diagnosis It is difficult to distin guish th e various types of MPSs on the basis of radiographic and clinical findings alone. One exception is Morquio syn drom e, wh ich can som etim es be distin guish ed from th e oth ers on th e basis of n orm al in telligen ce an d gen eralized join t laxity rath er th an con tracture. Gen erally, en zym atic assays an d bioch em ical tests of both urin e an d serum are n ecessary to m ake th e specific diagn osis. True skeletal dysplasias can be differentiated from MPS by the presence of characteristic clin ical features, genetic testin g, an d th e lack of abn orm al urin ary m etabolites. Treatment No cure exists for patien ts with MPS. Treatm en t, for th e m ost part, is supportive an d directed at symptom s. In patien ts with Hurler syn drom e, en zym atic replacem en t with recom bin an t α-l -iduron idase m ay improve som e of the clinical m anifestations of th e disorder. Un fortunately, patien ts usually presen t after th e on set of sym ptom s, an d treatm en t can n ot reverse th e perm an en t tissue dam age has already occurred. Allogen eic bone m arrow transplan tation m ay improve th e facial features an d th e h epatosplen om egaly but does n ot seem to alleviate th e m usculoskeletal abn orm alities. Patien ts with MPS h ave m ultiple m edical problem s due to th e in volvem en t of several organ system s. Consultation with the appropriate m edial specialists is n ecessary to m an age th e cardiac, respiratory, an d n eurologic issues th at can arise. O rth opaedic treatm en t in volves correction an d/ or stabilization of th e m usculoskeletal m an ifestation s of th e disorder. Join t con tractures th at are recalcitran t to stretch in g m ay

B

nance image in a 12-year-old boy with Morquio syndrome and declining ability to walk shows spinal cord compression and signal change associated with upper cervical instability resulting from his odontoid hypoplasia. (B) Postoperative lateral radiograph of the upper cervical spine illustrates solid occipital–C2 posterior fusion 6 months following the surgery. (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

require surgical release if th ey adversely affect fun ction . An gular deform ities of th e lower extrem ities that impair am bulation sh ould be treated by guided growth tech n iques or corrective osteotomy. Cervical in stability, especially in Morquio syn drom e, warrants atlan toaxial fusion and occasion ally occipitocervical fusion (Fig. 11.68). Progressive kyphoscoliosis should be stabilized by spinal fusion and instrum entation.

CHROMOSOMAL AND INHERITED SYNDROMES Down Syndrome (Trisomy 21) Pathophysiology Down syn drom e occurs in patien ts wh o h ave a th ird copy of ch rom osom e 21. In m ore th an 95% of patien ts, th is con sists of a complete duplication of the entire chrom osom e. A very sm all percentage of ch ildren (3%) actually have a translocation of part of chrom osom e 21 with a norm al total n um ber of ch rom osom es. Eith er way, it is th e duplication of several genes (all of which reside on the long arm of chrom osom e 21) th at is respon sible for producing the syndrom e. The m ale:fem ale incidence is equal, an d th e overall in ciden ce is approxim ately 1.5 children per 1,000 live births. The m ajor risk factor for having a child with Down syn drom e is advan ced m atern al age. Presentation and Physical Examination Down syn drom e is on e of th e m ost com m on an d recogn izable syndrom es in hum ans. Patients with Down syndrom e h ave a ch aracteristic facial appearan ce, wh ich includes upward-slan tin g eyes, epican th al folds, arch ed palate, an d flat face (Fig. 11.69). Short stature is typical, although patients are not n early as short as in m ost skeletal dysplasias. Men tal retardation is com m on but m ost children are able to fun ction at a low-n orm al level, perform activities of daily living, and work as adults in certain capacities. Gross m otor


281

patellofem oral ligam en t an d th e retin aculum are believed to be th e m ajor restrain ts in keepin g th e patella in th e in tercondylar groove, insufficiency of both of these structures allows subluxation . In addition , m any ch ildren with Down syn drom e h ave gen u valgum , which increases the likelih ood of patellar in stability. Foot abn orm alities are typical. Because of severe ligam en tous laxity, th e arch of the foot collapses and develops a planovalgus deform ity. Many children also h ave a prom in en t m etatarsus prim us varus an d a coinciden t bunion deform ity.

Figure 11.69 Clinical photograph of a child with Down syn-

drome (trisomy 21). Note the characteristic features including a small, rounded head; a flattened nasal bridge; oblique palpebral fissures; prominent epicanthal folds; small, low-set, shell-like ears; and a relatively large tongue. (Reproduced with permission from Pillitteri A. Maternal and Child Health Nursing. 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2003.)

developm en t is som ewh at delayed—ch ildren gen erally do not walk un til 2 to 3 years of age. Con genital heart disease is present in up to 50% of patients and usually consists of a septal defect. Life expectan cy in Down syn drom e is som ewh at shorter than n orm al, and a m ajor cause of early m ortality is cardiac disease. Other associated conditions include duodenal atresia, leukem ia, an d en docrinopathies such as hypothyroidism . Th e orth opaedic m an ifestation s in Down syn drom e have a com m on th read of path ology, n am ely in creased ligam entous laxity and joint hyperm obility. Laxity at the C1 –C2 articulation or the occipitocervical joint can result in cervical instability in up to 30% of patien ts. Most patients are asymptom atic, but oth ers m ay present with subtle neurologic findings such as easy fatigability, abnorm al gait, and clum sin ess. Any con cern should prompt a careful neurologic exam ination in cludin g an assessm ent of ton e, reflexes, m otor stren gth , an d sen sory deficits. Spin al deform ity, which behaves like idiopathic scoliosis, is seen in approxim ately 50% of patien ts. Hip subluxation an d dislocation is a m ajor problem in Down syndrom e, occurring in up to 10% of ch ildren . Un like developm en tal dysplasia of th e hip (DDH), hip dysplasia in Down syn drom e is n ot presen t at birth but develops between th e ages of 2 and 10 as a result of ligam en tous laxity an d join t hyperm obility. Oth er com m on hip disorders include SCFE an d avascular necrosis. At th e knee, patellar instability an d subluxation is a direct result of ligam en tous laxity. Because th e m edial

Radiographs Because of the h igh in ciden ce of upper cervical in stability, flexion –exten sion lateral views of th e cervical spin e sh ould be obtain ed to m easure th e atlan toden s in terval. Values greater th an 5 m m are con sidered diagn ostic of in stability. Screening radiographs of the cervical spine are gen erally required by the Special Olympics before a ch ild with Down syn drom e can be cleared for participation . In cases of suspected h ip path ology, an AP an d frog lateral view of th e pelvis is warran ted. Radiograph s typically dem on strate flat, dysplastic acetabuli, an d flared iliac win gs. In certain children who complain of hip instability, the fem oral heads m ay be well covered with a norm al fem oral neck–sh aft angle and m oderately in creased fem oral anteversion. In these cases, th e source in stability is laxity of th e h ip capsule an d supportin g ligam en ts. Special Studies Pren atal screen in g for Down syn drom e in cludes m easures of serum α-fetoprotein, estriol, and hum an chorionic gon adotropin . These levels are decreased, decreased, and in creased, respectively, in th e presen ce of a Down fetus. If th ese screen in g tests dem on strate an in creased risk of trisomy 21, am niocentesis and chrom osom al analysis can be perform ed to yield a defin itive diagn osis. CT scans m ay be useful prior to hip reconstruction to evaluate th e version of th e acetabulum an d to iden tify areas of acetabular deficien cy. MRI of th e cervical spin e is indicated in cases of severe atlantoaxial instability or neurologic comprom ise. Treatment Th e surgical treatm en t of ch ildren with Down syn drom e can be frustratin g sin ce th e sam e ligam en tous laxity th at causes th e in itial deform ity also in creases th e ch an ce of recurren ce. As a result, con servative treatm en t is preferred wh en ever possible. Th e m an agem en t of upper cervical spin e in stability is som ewhat con troversial. Since m ost patien ts with m oderate degrees of atlantoaxial instability will rem ain asymptom atic, and the complications of surgery can be significan t, th e role of prophylactic surgical stabilization rem ain s un clear. In gen eral, asym ptom atic ch ildren with an atlan toden s in terval between 5 an d 10 m m sh ould be coun seled to avoid high-risk sports such as diving and gym nastics.

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A

B Figure 11.70 The management of hip instability from Down syndrome can be challenging. This boy presented after a few episodes of acute pain, but radiographs demonstrate a reduced, irregularly shaped femoral heads, and irregularly shaped acetabuli that seem to provide good “coverage.” (B) He returns 3 years later with a painful, fixed dislocation of the left hip, subluxation of the right hip, and shallow, dysplastic acetabuli. (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Patien ts with instability th at exceeds 10 m m should be considered for upper cervical fusion . Of course, any child with a n eurologic deficit sh ould un dergo realign m en t an d fusion . In cases of deficient posterior elem en ts or occipitocervical instability, the arthrodesis should be extended to the occiput. The m anagem en t of hip disorders is equally ch allengin g. Hip in stability an d recurren t dislocation s are gen erally pain less but m ay h asten th e developm en t of degen erative arth ritis (Fig. 11.70). Spica castin g an d abduction bracin g can h elp stabilize a h ip in youn ger patien ts. In older patien ts, especially th ose th at are sym ptom atic, recon struction can be perform ed via a varus fem oral osteotomy an d/ or redirection al acetabular osteotom y. Complication s after surgery are com m on , m ost n otably redislocation an d in fection . Patellar instability sh ould be initially treated by quadriceps strengthenin g an d stabilizin g braces. For th ose that fail con servative m an agem en t, both soft tissue an d bony surgery should be perform ed to m inim ize the risk of recurren ce. Usually th is in volves a m edial patellofem oral plication or recon struction in addition to a tibial tubercle tran sfer for skeletally m ature patien ts or a m edial transfer of the lateral h alf of th e patellar ten don (Roux–Goldth waite procedure) for skeletally im m ature patients. In certain cases, treatm en t of coexistin g gen u valgum with h em iepiphysiodesis or corrective osteotomy will improve th e success rate following surgery. Pes planovalgus is generally pain less and treatm en t is un n ecessary un less sym ptom s develop. In th ese cases, sh oewear m odifications an d orth otics should be the first lin e of treatm en t. For recalcitran t cases, calcan eal osteotomy to correct th e h in dfoot valgus can be con sidered. Sim ilar to th e flatfoot deform ity, h allux valgus sh ould be treated con servatively wh en ever possible. If surgery is n ecessary, th e first MTP join t sh ould be fused to m in im ize th e risk of recurrence.

Marfan Syndrome Pathophysiology Marfan syndrom e results from a defect in the gene th at codes for fibrillin , located on th e long arm of chrom osom e 15. Fibrillin is a glycoprotein that is closely associated with elastin an d is an im portan t com pon en t of several types of tissues, including skin, ligam en t, tendon, and blood vessels. Adefect in th is gen e ch anges the m ech anical properties of all of th ese tissues, leadin g to in creased laxity. Fibrillin m utations also are though t to increase the availability of certain extracellular growth factors to cell receptors, leading to an increase in longitudinal growth . Marfan syndrom e is gen erally inherited in an autosom al dom inant fashion, although up to 30% of patients m ay h ave a spontan eous m utation. The prevalence of the disease is approxim ately 1 per 10,000 people in th e Un ited States. Presentation and Physical Examination Like m any syndrom es of orthopaedic importance, Marfan syn drom e presen ts with a ch aracteristic appearan ce (Fig. 11.71). Patients are gen erally tall and lanky with lon g, thin lim bs. The digits are long and spider-like (arachn odactyly). Two ch aracteristic exam in ation fin din gs in th e h an ds an d digits, wh ile n ot diagn ostic, are h igh ly suggestive of th e disease. Th e first is th e Stein berg sign , in wh ich th e th um b exten ds past th e uln ar border of th e h an d wh en th e fist is clen ch ed (Fig. 11.72). Th e secon d is overlap of the thum b and index finger when the patien t’s han d is wrapped aroun d the contralateral wrist. Facial deform ities include a high-arched palate, narrow face, and progn ath ism . Ch est wall deform ities such as pectus excavatum or pectus carin atum are typical. Join t laxity can lead to pes plan ovalgus, gen u recurvatum , or join t dislocation . Scoliosis occurs in m ore than 30% of patien ts. Kyphosis and spon dylolisth esis can also be seen. Ch ildren with Marfan syn drom e h ave m any n on orthopaedic issues that warrant evaluation by a specialist.


283

Figure 11.72 Steinberg thumb sign is useful in the diagnosis of Marfan syndrome. (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

aortic aneurysm or dissection. Murm urs from aortic or m itral valve insufficiency are often audible. Figure 11.71 Clinical appearance of a patient with Marfan syn-

drome. Note extreme myopia (represented by thick corrective lens), severe pectus excavatum, long limbs, and arachnodactyly. The patient also has scoliosis and severe planovalgus feet. This appearance is typical of patients with florid manifestations of this syndrome. (Reproduced with permission from Herring JA. Tachdjian’s Pediatric Orthopaedics. 3rd ed. St. Louis, MO: Saunders, 2002.)

Ophthalm ologic consultation is n ecessary to screen for ectopia len tis (dislocated len s) th at is caused by lax suspen sory ligam ents th at allow superior m igration of th e len s. Testin g of visual acuity m ay reveal myopia that results from the abnorm al shape of the globe. Referral to a cardiologist is essential as patients with Marfan syndrom e can develop dilation of the ascending aorta and m itral valve in sufficien cy. Altered elasticity in the vessel walls can lead to

Figure 11.73 Hands showing arachnodactyly. Notice the long, thin metacarpals and phalanges. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Radiographs Th e diagn osis of Marfan syn drom e is a clin ical on e; h owever, radiograph s can be h elpful to support th e diagn osis and to evaluate an atom ical areas of concern. Spinal radiograph s m ay sh ow scoliosis, kyph osis, or spon dylolisth esis. In particular, signs of dural ectasia and pedicle dysplasia can be seen (in creased in terpedicular distan ce an d increased sagittal diam eter of L5). Radiographically, arachnodactyly can be quantified by m easuring the length to width ratios of the second through fifth m etacarpals on a posteroan terior view of th e h an d (Fig. 11.73). An AP view of th e pelvis m ay sh ow sign s of protrusio acetabuli; th is is defined as intrapelvic intrusion of the acetabulum such th at th e m edial edge of th e fem oral h ead lies m edial to th e ilioischial line (Fig. 11.74).

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lopathy. In addition, the direction of lens dislocation is classically inferior as compared with th e superior direction th at occurs in Marfan syndrom e. The diagnosis can be con firm ed by testin g th e urin e for h om ocystin e. Stickler syn drom e (hereditary progressive arthro-opthalm opathy) presen ts with lon g, th in lim bs such as in Marfan syn drom e. However, radiographs will dem onstrate features sim ilar to m ild spondyloepiphyseal dysplasia. Ocular m anifestations m ore com m only include myopia and retinal detachm ent rath er th an ectopia len tis. Eh lers–Dan los syn drom e is a collection of disorders ch aracterized by excessive join t laxity an d skin hyperelasticity. Joint dislocations, easy bruisability, and “cigarette paper’’skin are the m ajor m anifestations, but h eigh t is gen erally n orm al an d arach n odactyly is rare. Figure 11.74 Anteroposterior radiograph of the pelvis in an

8-year-old girl with Marfan syndrome. Note the bilateral acetabular protrusio with intrusion of the medial wall of the acetabulum to the ilioischial line.

Special Studies In spite of th e kn owledge of wh ich gen e causes Marfan syn drom e, n o specific laboratory test exists to m ake a defin itive diagn osis. CT scan s can be useful to defin e th e bony an atomy of complex h ip or spin e deform ities. Dural ectasia is best dem on strated on a lum bosacral MRI. Slit lamp exam in ation an d ech ocardiography are essen tial studies for oph th alm ologic an d cardiac evaluation s respectively. Differential Diagnosis Marfan syn drom e is a clin ical diagn osis th at is based on defin ed m ajor an d m in or criteria in volvin g several organ system s (Table 11.4). Th e differential diagnosis for Marfan syn drom e in cludes several oth er con dition s th at can exh ibit sim ilar features. Hom ocystin uria is caused by a defect in the enzym e that converts cysteine to m ethionine. Th e con dition resem bles Marfan syn drom e except th at it is often associated with m en tal retardation an d a coagu-

TABLE 11.4

BERLIN CRITERIA FOR DIAGNOSIS OF MARFAN SYNDROMEa Major Involvement

Minor Involvement

Ocular system Cardiovascular system Dural ectasia

Skeletal system Ocular system Cardiovascular system Pulmonary system Skin Central nervous system

a

If a patient has an affected first-degree relative, at least two systems of any class must be involved. In the absence of an affected first-degree relative, involvement of the skeleton and one major system and two minor systems are required. (Adapted from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Treatment Currently, there is n o specific treatm en t for the genetic defect responsible for Marfan syn drom e. Therefore, treatm en t is aim ed at m anaging the condition s associated with the syn drom e. As m ention ed, early referral to an ophthalm ologist an d cardiologist is importan t to preven t or treat ocular an d cardiac problem s. The use of β -blockers can reduce the risk of aortic dilation . For in com peten t aortic roots, aortic valves, or m itral valves, replacem ent sh ould be considered. Th e treatm en t of scoliosis in Marfan syn drom e is sim ilar to th at of idiopath ic scoliosis. Bracin g is recom m en ded for curves greater than 25 degrees, alth ough som e authors have suggested th at bracin g m ay be less effective in th is patient population . Surgery (usually posterior spin al fusion an d instrum entation) is indicated for progressive curves that exceed 45 to 50 degrees. Com plication s are m ore com m on than with idiopathic scoliosis and include pseudarthrosis, infection, dural tear, residual curve decompen sation, and loss of fixation in dysplastic posterior elem ents. Protrusio acetabuli is generally observed. In skeletally im m ature patien ts, Steel h as described closure of th e triradiate cartilage to m in im ize further acetabular deepening. In older, sym ptom atic patien ts, h ip arthroplasty can be considered. Th e flatfeet an d occasion al join t dislocation s th at result from generalized laxity are best m anaged conservatively with bracin g an d physical th erapy. For severe cases, surgical correction m ay be warranted.

LIMB DEFICIENCIES Proximal Femoral Focal Deficiency Pathophysiology Proxim al fem oral focal deficien cy (PFFD) refers to a spectrum of disorders ch aracterized by a variably shorten ed fem ur with or without an abnorm ality of the fem oroacetabular articulation . Th e in ciden ce of th e deficien cy ran ges from 1 case per 50,000 to 1 case per 200,000. The etiology of PFFD is n ot well un derstood, but certain th eories h ave been proposed. Th e sclerotom e subtraction th eory suggests


Type

Femoral Head

Acetabulum

Femoral segment

285

Relationship among components of femur and acetabulum at skeletal maturity Bony connection between components of femur

A

Present

Normal

Short

Femoral head in acetabulum Subtrochanteric varus angulation often with pseudarthritis

B

C

Present

Absent or represented by ossicle

Short, usually Adequate or proximal moderately bony tuft displastic

Severely displastic

Short, usually proximally tapered

No osseous connection between haed and shaft Femoral head in acetabulum

May be osseous connection between shaft and proximal ossicle No articular relationship between femur and acetabulum

Absent

D

Absent

Obturator fpramen enlarged

Short, deformed

(none)

Pelvis squared in bilateral cases

Figure 11.75 Aitken classification for proximal femoral focal deficiency. (Redrawn from Herring JA. Tachdjian’s Pediatric Orthopaedics. 3rd ed. St. Louis, MO: Saunders, 2002.)

that injury to th e neural crest cells that form the precursors to th e periph eral sen sory n erves of L4 an d L5 results PFFD. A second theory contends that PFFD m ay be the result of a defect in proliferation an d m aturation of ch on drocytes in the proxim al growth plate. Anoxia, ischem ia, irradiation, bacterial an d viral in fection s, toxin s, h orm on es, m ech an ical en ergy, and th erm al injury have all been suggested as possible causative factors. One well-known teratogen, thalidom ide, has been implicated as a direct cause of PFFD wh en taken by th e m oth er between th e fourth an d sixth weeks of gestation . Curren tly, n o eviden ce exists for a genetic etiology.

graphic appearance of th e hip and th e length of the fem oral segm ent (Fig. 11.75). Gillespie proposed a m ore function al classification system in wh ich h e divided h is patien ts in to th ree groups based on treatm en t option s. Group Acon sists of cases previously called congenitally short fem urs; these children have norm al hip joints an d the length of the affected lim b com es to the contralateral tibia or lower. Group B patien ts h ave hip involvem ent sim ilar to Aitken A, B, or C but h ave larger leg len gth discrepan cies th an group A, with the length of the affected lim b com ing to th e level of the contralateral knee or above. Gillespie group C patien ts are sim ilar to Aitken D with n ear absen ce of th e fem ur.

Classification Th e Aitken classification is th e m ost widely used classification. It divides PFFD into four categories based on the radio-

Presentation and Physical Examination Children present soon after birth with obvious shortening and deform ity of the affected lim b. The bulbous proxim al

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Figure 11.77 Anteroposterior view of the pelvis and lower ex-

Figure 11.76 Photograph of a 12-month-old girl who demon-

strates the clinical features of proximal femoral focal deficiency: a very short and bulbous femoral segment which is flexed, abducted, and externally rotated. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

thigh quickly tapers to th e knee, and the thigh is usually flexed, abducted, and externally rotated (Fig. 11.76). Physical fin din gs m ay in clude proxim al join t in stability, kn ee in stability (from absen ce of th e an terior cruciate ligam en t), an d variable deficien cy of th e proxim al m usculature. Flexion con tractures of both th e h ip an d th e kn ee are com m on . In up to 50% of cases, th e ch ild will h ave an ipsilateral fibular deficien cy with a equin ovalgus foot deform ity. Lateral rays of the foot m ay be m issing. PFFD can be bilateral in up to 15% of cases. Rem arkably, ch ildren with PFFD com pen sate well for their deform ity and do not have a delay in th eir gross m otor developm en t. Most ch ildren walk at th e expected age eith er by toe-walking on the short side (for m ild cases) or by bearin g weigh t on th e kn ee of th e n orm al side an d th e foot of th e sh orten ed lim b (for m ore severe cases).

Imaging Radiograph s are essen tial to determ in e th e degree of fem oral hypoplasia and to establish the status of the h ip joint (Fig. 11.77). The percentage of th e discrepan cy can be estim ated by com parin g th e sh ort lim b with th e con tralateral side. O ften , ossification of th e proxim al fem ur will be

tremities in an 18-month-old child with bilateral proximal femoral focal deficiency. The right hip is an Aitken class A and demonstrates the presence of an ossific nucleus and a good acetabulum. The opposite hip is an Aitken class C. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

delayed, m akin g arth rography or MRI n ecessary to determ ine the presence or absence of a cartilaginous anlage.

Differential Diagnosis Th e diagn osis of PFFD is gen erally straigh tforward. Occasion ally, PFFD can be confused with congen ital coxa vara with an associated sh ort fem ur. Th e latter con dition h as a varus n eck–shaft an gle with deform ation of all of the components of the head, neck, and trochan teric area and sh orten ing of th e fem ur. This is, however, an entirely different entity, an d radiographs at approxim ately 1 year are gen erally sufficien t to distin guish th e two con dition s. Treatment Th e m an agem en t of PFFD requires a m ultidisciplin ary team , wh ich in cludes th e pediatric orth opaedic surgeon , prosth etists, an d physical th erapists. No sin gle treatm en t approach applies to all cases, and each patient with PFFD m ust be assessed individually. In gen eral, treatm en t is guided by th e expected discrepan cy at m aturity an d stability of th e hip joint. Since the relative proportion of th e sh orten ed lim b to th e n orm al lim b rem ains constant durin g growth, th e expected discrepancy can be calculated by m ultiplying the percentage of th e existin g discrepan cy (at th e tim e of diagn osis) with


the average length of an adult fem ur. Those children who have a predicted discrepan cy less than 20 cm (Gillespie A) are good candidates for lim b length en ing. To prevent iatrogenic hip dislocation, the hip join t should be stabilized before len gth en in g th e fem ur. Ch ildren with greater th an 20 cm of expected discrepan cy (Gillespie B) can be m anaged in several different ways.

A,B

287

If th e h ip is stable, kn ee fusion followed by eith er Van Nes rotationplasty or Sym e amputation preserves len gth of th e lim b an d facilitates prosth etic fittin g. Th e Van Nes rotationplasty rotates th e lim b 180 degrees such th at th e an kle becom es th e n ew kn ee join t (Fig. 11.78). Wh ile h igh ly fun ction al, rotationplasties are som etim es difficult to accept from a cosm etic stan dpoint and can derotate som ewhat

C

Figure 11.78 Results of a Van Nes rotationplasty in a 17-year-old

D

girl with proximal femoral focal deficiency. With the ankle rotated 180 degrees, dorsiflexion of the ankle (A) results in flexion of the prosthetic knee (B), and plantar flexion (C) results in extension of the prosthetic knee (D). (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

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with continued growth . Sym e amputation s are preferred if the foot and an kle do not function well or if the patien t cannot tolerate the cosm etic appearance of the rotationplasty. For Gillespie B patien ts with an un stable h ip, iliofem oral fusion m ay be necessary to stabilize the hip prior to a Sym e amputation or rotationplasty. Most patien ts with n ear total absen ce of th e fem ur (Gillespie C) sh ould be m an aged with a prosthesis.

Fibular Hemimelia Pathophysiology Fibular h em im elia, or postaxial hypoplasia of th e lower extrem ity, is th e m ost com m on lower lim b deficien cy syn drom e. By defin ition , fibular h em im elia is a lon gitudin al deficien cy of th e lateral portion of th e lower lim b in wh ich part or all of th e fibula m ay be m issin g. It can occur in isolation or as part of PFFD an d varies in severity from m ild to severe deform ity. Th e etiology of fibular h em im elia rem ain s un clear, but th e m ost popular th eory proposes th at in terferen ce with th e early developm en t of th e lim b bud plays an essen tial role. Classification Several classification system s exist for fibular h em im elia. Th e Ach term an –Kalam chi classification system is based on fibular m orph ology. In type IA, th e proxim al fibular epiphysis is distal to th e level of th e tibial growth plate with the distal fibular physis proxim al to the talar dom e. Type IB is ch aracterized by a proxim al fibula th at is 30% to 50% sh orter than norm al (Fig. 11.79). Th e distal fibula is presen t but does n ot adequately support th e an kle. Type II deform ities refer to complete absen ce of th e fibula.

A

B

Figure 11.79 (A and B) Type IB fibular deficiency in which the

proximal fibula is missing. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Presentation and Physical Examination Ch ildren with fibular deficiency present early in life with sh orten ing and deform ity of th e affected extrem ity (Fig. 11.80). Depending on the degree of fibular hypoplasia (or aplasia), a variable am ount of fem oral shortening can be seen. Oth er coexisting con ditions can include genu valgum , a hypoplastic lateral fem oral condyle, tarsal coalition, an d

Figure 11.80 (A and B) Clinical appearance of

A

B

a child with complete absence of the fibula (type II deformity). Note the short tibial segment, the valgus knee and foot, and the dimple over the tibia. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)


absence of th e anterior cruciate ligam ent. Without a proper lateral m alleolus as part of the ankle m ortise, th e foot tends to develop an equin ovalgus deform ity, an d an kle in stability is com m on. In cases of complete fibular absen ce, anterom edial bowing of th e tibia can be seen. Depen ding on the severity of th e fibular deficien cy, the lateral rays of th e foot can be m issin g.

Radiographs A stan din g AP view of th e h ips to an kles sh ows th e overall alignm ent of the affected lower extrem ity and perm its use of th e con tralateral side as a con trol. Lim b-len gth discrepan cies are best m easured by using scanogram s (see section on leg len gth discrepan cy). Abn orm alities in specific parts of th e lower extrem ity can be seen an d, if n ecessary, im aged further with specific views. For example, if there is con cern about coexistin g PFFD and/ or acetabular dysplasia, a pelvis an d/or hip series should be ordered. Sim ilarly, a knee series is useful for evaluatin g distal fem ur valgus, hypoplasia of th e lateral fem oral con dyle, an d flatten in g of th e tibial em in en ce. Differential Diagnosis Th e ch aracteristic clin ical appearan ce an d plain radiograph s are gen erally sufficien t to m ake th e diagn osis. As m en tion ed, several other conditions are associated with fibular h em im elia an d each sh ould be evaluated in dividually. Treatment As with PFFD, the ultim ate goal of surgery is to achieve sym m etrical, stable, and well-align ed joints with the m in im al num ber of surgical procedures. No single set of operation s sh ould always be perform ed; in stead, in dividual procedures sh ould be plan n ed th at address th e specific abnorm alities in each patient. Fin ally, realistic expectation s of the tim ing, the duration of recovery, and the ultim ate outcom e m ust be com m unicated to patients and th eir fam ilies. Treatm en t is gen erally guided by th e degree of fibular sh ortenin g, the expected leg len gth discrepan cy at skeletal m aturity, and the quality of the foot. Patients with m ild to m oderate discrepancies (0% –10%) an d a fun ction al foot can be m anaged with shoe lifts, orthoses, and/ or a welltim ed contralateral epiphysiodesis. Patients with larger discrepancies and an adequate foot generally require on e or m ore lim b len gthening procedures. If the foot is nonfunctional either due to an unstable ankle or due to an insufficien t n um ber of rays (gen erally th ree or fewer), stron g con sideration should be given toward an early Sym e am putation . Studies h ave sh own im proved fun ction an d n orm alized gait param eters in patients who underwent early amputation and prosthetic fitting compared with those wh o un derwen t (often several) lim b salvage procedures. Amputation is certainly in dicated for th ose patients with complete absence of th e fibula.

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Several of the associated condition s with fibular h em im elia m ay warran t treatm en t. Gen u valgum is often progressive, an d it can adversely affect align m en t of th e lower lim b. Th is can be treated in several ways. Acute correction can be obtain ed by m ean s of a distal fem ur corticotomy durin g a fem oral len gth en in g procedure or by m ean s of temporary m edial epiphyseal staplin g. As m en tion ed, an kle abn orm alities can ran ge from complete absen ce of the fibula to ankle valgus and/ or a ball-and-socket an kle. In m ild cases, a m edial m alleolar screw epiphysiodesis can improve align m en t an d provide good results. Procedures in th e foot in clude resection of tarsal coalition s or fusion s an d addressin g any problem s with sh oe fit th at m igh t arise for any deform ity.

Tibial Hemimelia Tibial h em im elia is a rare con gen ital an om aly ch aracterized by deficiency of the tibia with a relatively intact fibula. Th e exten t of th e deficien cy is variable: th e type I form is characterized by total absence of the tibia; type II has a persisten t proxim al tibia; type III (rare) is ch aracterized by th e presen ce of a distal tibia on ly; an d in type IV, th ere is a divergen ce of th e distal tibia an d fibula, with proxim al displacem en t of th e talus. Th e prevalen ce of tibial h em im elia is estim ated at 1 in 1,000,000 live births. Although the m ajority of cases with tibial h em im elia are sporadic, affected fam ilies with possible autosom al dom in an t or autosom al recessive in h eritan ce h ave been reported Most children present early in life with th e characteristic deform ity of th e lower lim b (Fig. 11.81). If the entire tibia is absen t, there is often a fixed proxim al and lateral position of th e fibula with severe flexion deform ity. Th e affected lim b is usually short, with the foot in an “apparen t clubfoot’’position of equin ovarus. Th e m ost importan t com pon en t of th e evaluation is to determ in e th e am oun t of proxim al tibial th at exists an d to determ in e wh eth er th ere is a fun ction al quadriceps. Radiograph s are usually h elpful to determ in e th e degree of tibial hypoplasia, but ossification of th e proxim al tibia is often delayed so ultrason ography or MRI m ay be necessary to establish the presence or absence of a cartilagin ous an lage. If th e en tire tibia is absen t, th ere is often a fixed proxim al and lateral position of th e fibula with severe flexion deform ity. Knee disarticulation is generally preferred for this con dition , alth ough cen tralization of th e fibula (Brown procedure) com bin ed with Sym e am putation h as been described. If en ough proxim al tibia is present such that the quadriceps attach m en t is preserved, th e en d of th e tibia can be fused to th e fibula with a Sym e am putation , an d a very reason able fun ction al lim b can be ach ieved.

Radial Clubhand Axial deficien cies on th e radial side of th e forearm are th e m ost com m on lim b deficiencies in the upper extrem ity.

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A,B

C Figure 11.81 (A and B) Radiographs of an infant with complete absence of the tibia (type I

deficiency). (C) The clinical appearance, with the medial deviation and severe equinus of the foot and the absence of any tibial structure below the distal femur. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Th is particular con gen ital lon gitudin al deficien cy is reportedly tran sm itted as an autosom al dom in an t trait. Radial clubhand is ch aracterized by partial or complete absence of the radius, with rare involvem ent of the ulnar ray. The han d is typically radially deviated an d m ay be lackin g a th um b (Fig. 11.82). Th e incidence is 1 in 100,000 live birth s, with approxim ately on e-h alf of th e cases bein g bilateral. It is im portan t for the treating physician to recognize th at radial deficiencies m ay be associated with other syn drom es in up to 50% of cases. TAR syn drom e (th rom bocytopen ia an d absen t radius) is on e of th e m ore com m on of th ese conditions. VATER syn drom e also h as radial deficiencies alon g with vertebral, an al, trach eoesoph ageal, an d ren al abn orm alities. Despite th e deform ity, h an d fun ction is usually surprisin gly good. As with m any of th ese an om alies in youn g ch ildren , adaptive tech n iques develop rapidly. Th erefore, it is importan t n ot to sacrifice a competen t fun ction in g h an d in an effort to correct wh at th e physician m ay feel is an un acceptable position . Stretch in g an d splin tin g are largely in effective for th e defin itive treatm en t of radial clubh an d but can som etim es be h elpful to stretch th e soft tissues preoperatively. Surgically, several differen t cen tralization procedures have been described. All involve a soft tissue release an d cen tralization of th e carpus on to th e distal uln a. Such procedures sh ould be con sidered on ly in ch ildren with

Figure 11.82 A patient with complete absence of the radius and

thumb aplasia. Note the foreshortening of the forearm and the 90degree radial deviation at the wrist. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)


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sufficien t elbow flexion so th at th ey can still get th e han d to th e m outh after a cen tralization procedure. In tern al fixation techniques and the use of external fixators have both been described.

ARTHRITIS In flam m ation or irritation of th e join t can occur due to both in fectious an d n on in fectious etiologies. Th e m ost im portan t cause of acute arth ritis in ch ildren is septic arth ritis, wh ich is discussed in Ch apter 5. O th er com m on causes of arthritis in clude tran sient syn ovitis, Lym e disease, and juven ile rheum atoid disease.

Transient Synovitis Pathophysiology Transient synovitis or toxic synovitis is a reactive arthritis that characteristically affects the hip. While the true cause is unknown, m ost auth ors believe that transien t syn ovitis is a nonspecific inflam m atory con dition. O thers have suggested that th e condition is a postviral allergic synovitis sin ce it tends to follow recent viral illn esses. Presentation Transient synovitis is one of the m ost com m on causes of hip pain and limp in young children . Children typically presen t between th e ages of 3 an d 9 with th e acute on set of groin or th igh pain an d lim pin g. Most patien ts are afebrile or m ain tain a low-grade fever (tem perature below 38 ◦ C). History and Physical Examination With a careful history, one can frequently uncover a h istory of upper respiratory tract in fection or ear in fection with in several weeks of th e onset of th e limp. As a result, som e authors have suggested that the condition is a postviral allergic synovitis. Physical exam ination will reveal restricted m otion of the hip, particularly in in ternal rotation and exten sion . Most patien ts are am bulatory an d system ic fin dings of infection are absent. Diagnostic Studies Laboratory studies are helpful in distinguish ing transien t syn ovitis from septic arthritis. In flam m atory m arkers are relatively n orm al, but on occasion , a m ild elevation in the ESR is observed. Radiograph s are typically n orm al; in rare cases, MRI or CT m ay be n ecessary to rule out oth er diagn oses. Ultrasoun d will often dem on strate a m ild to m oderate join t effusion (Fig. 11.83). In cases in which septic arthritis is still a concern, aspiration of the joint will yield a definitive diagnosis as the cell counts in transien t syn ovitis are with in the range of n orm al.

Figure 11.83 Longitudinal linear ultrasonographic view of the

hips in a 6-year-old girl with transient synovitis. Ultrasonographic scan of the symptomatic hip demonstrates a large effusion in the joint as indicated between the cursor markings. Depending on the clinical presentation, aspiration may be necessary to differentiate an effusion from transient synovitis from a septic effusion. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Differential Diagnosis Alth ough th e con dition is com m on , tran sien t syn ovitis is a diagn osis of exclusion ; oth er cause of pain an d limp m ust be ruled out before one settles on th e diagnosis. Th e differen tial diagn osis in cludes lym e arth ropathy, juven ile rh eum atoid arth ritis (JRA), an d traum a. Th e m ost importan t diagn osis to rule out is septic arth ritis. Usually, patients with septic arthritis will refuse to bear weight, have fevers with temperature higher th an 38.5 ◦ C, and have elevated laboratory results, including white blood cell count, sedim en tation rate, an d C-reactive protein. If there is any doubt regardin g th e diagn osis, an arth rocen tesis sh ould be perform ed. Treatment Th e treatm en t of tran sien t m on oarticular syn ovitis of th e h ip is symptom atic as th e con dition is self-lim ited. Recom m ended therapies include activity lim itation and relief of weigh t-bearin g un til th e pain subsides. An ti-in flam m atory agen ts and analgesics m ay shorten th e duration of pain. Most ch ildren recover completely within 2 to 3 weeks.

Lyme Arthritis Pathophysiology Lym e disease is a tick-born e in flam m atory disorder caused by th e spirochete Borrelia burgdorferi. It is m ost com m on ly

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veal single or m ultiple joint involvem ent. These joints are usually h ot, swollen , an d pain ful an d often resem ble classic pyogen ic septic arth ritis. Am bulatory ability is variable as is the presence of a fever. Range of m otion is norm ally restricted because of th e effusion, but patients have less pain with m icrom otion compared with pyogen ic in fection s.

Figure 11.84 Primary erythema chronicum migrans lesion. (Re-

produced with permission from Fleisher GR, Ludwig S, Henretig FM, et al. Textbook of Pediatric Emergency Medicine. 5th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

tran sm itted by th e deer tick, Ixodes dammini. Nam ed for the town in Con n ecticut wh ere on e of th e origin al outbreaks occurred, Lym e disease is en dem ic to th e n orth east Un ited States alth ough it h as been reported across th e coun try. As on e would expect, th e h igh est rates of disease occur in th e sum m er an d fall an d coincide with h igh deer activity an d high outdoor activity by children.

Presentation Typically, th e disease presen ts in th ree stages. Th e first stage lasts days to weeks an d is ch aracterized by system ic symptom s (fever, m alaise) an d th e classic eryth em a ch ron icum m igran s (ECM) (Fig. 11.84). ECM is an expan din g m acular eryth em atous rash with a cen tral clearin g. Th is “bulls-eye’’ rash is seen only in 50% of ch ildren and usually occurs on th e th igh , groin , or axilla. Th e secon d stage, wh ich lasts weeks to m onths, is typified by cardiac and neurologic involvem en t. Th e cardiac sequelae can in clude varyin g degrees of h eart block an d m yocarditis, an d th e n eurologic fin din gs can in clude m en in gitis, en ceph alitis, ch orea, an d Bell palsy. Th e th ird stage, wh ich can persist for m on ths to years, is ch aracterized by fran k arth ritis. In term itten t attacks of asym m etrical join t swellin g an d pain , prim arily in th e large join ts (e.g., kn ee), are typical. Ch ildren are, in gen eral, m ore susceptible to th e acute sym ptom s of Lym e disease th an th e ch ron ic effects. History and Physical Examination Importan t elem en ts of th e h istory in clude livin g in , or recen t travel to, th e n orth east Un ited States, especially in region s th at are h eavily wooded, an d oth er poten tial en viron m en tal exposures. Ch ildren an d fam ilies will often n ot rem em ber bein g bitten by a tick, alth ough th ey m ay recall the presence of th e ECM rash . Physical exam ination can re-

Diagnostic Studies Laboratory tests m ay show m ild elevation in levels of inflam m atory m arkers such as sedim entation rate or Creactive protein but are usually n ot in creased to th e levels seen in pyogen ic arth ritis. Arth rocen tesis will reveal wh ite blood cell coun ts in th e ran ge of 25,000 to 50,000 cells/ m L. Attempts at culture, when positive, are clearly diagnostic of the disease, but retrieval of organism s is very low. Blood tests for antibodies sh ould be routinely perform ed as part of the diagnostic workup; however, there is a substan tial false-negative rate early in the disease process. A two-tiered test including an enzym e-linked im m unosorben t assay (ELISA) test (h igh sen sitivity) an d a Western blot (high specificity) is the diagnostic m ethod of ch oice. Differential Diagnosis Depen din g on th e severity of th e presen tation , Lym e disease can be difficult to separate from pyogen ic septic arth ritis or toxic synovitis. History an d physical exam ination con sistent with Lym e disease should prompt appropriate laboratory tests to confirm or rule out the diagnosis. Treatment Ch ildren with Lym e disease are usually treated with a prolonged course of am oxicillin . Advan ced cases th at have crossed th e blood –brain barrier m ay require ceftriaxon e. Most ch ildren who are diagnosed early and treated appropriately will m ake a rapid an d full recovery.

Juvenile Rheumatoid Arthritis JRA, also known as Still disease, curren tly affects nearly 400,000 ch ildren in th e Un ited States. Th ere are two in cidence peaks during ch ildh ood: one group younger than 6 years an d an oth er between 10 an d 15 years of age.

Pathophysiology Th e exact etiology of th e disease rem ain s un kn own . O ccasion al referen ces h ave been m ade to an association with an initiating traum atic event. Th e com m on thread that relates this entity to the adult form of rheum atoid arthritis is an exaggerated im m unologic respon se in the synovium . Th is syn ovial proliferation an d release of lysosom al en zym es cause th e ch aracteristic progressive join t destruction . In addition , th e th icken ed pan n us an d resultan t effusion cause ligam en tous stretching and m echanical dam age to the join t (Fig. 11.85). An addition al risk in children is th e effect of th e hypervascular gran ulation tissue on th e physis.

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A

B

Figure 11.85 Synovitis and fluid in the knee of a

C

Stim ulation of th e growth plate frequen tly causes overgrowth of th e lim b.

Classification and Presentation JRA can be classified into one of three form s: system ic, polyarticular, or m on oarticular (pauciarticular) disease. Th e system ic form of JRA is an acute febrile illn ess representin g approxim ately 20% of all patients. These children consisten tly presen t with a waxin g an d wan in g fever an d a rash that is nonpruritic an d evan escent (Fig. 11.86). Approxim ately 85% will also dem on strate hepatosplenom egaly. Polyarticular disease is seen in approxim ately 50% of involved children. Although chronically ill in appearance an d stunted in th eir growth, these children do not m anifest the generalized system ic symptom s seen in the previous group. Ch aracteristically, m ultiple large join ts (classically the knee) are involved (Fig. 11.87). However, sm all joints

15-year-old girl with juvenile rheumatoid arthritis. (A) A sagittal T1-weighted magnetic resonance image (MRI). (B) T1-weighted MRI after gadolinium injection. (C) T2weighted MRI showing high-signal areas (white) in the suprapatellar pouch and the posterior compartment. By comparing the pre (A) and post (B) contrast studies, the hypervascular inflamed synovium is enhanced (appears white). (Reproduced with permission from Koopman WJ. Arthritis and Allied Conditions: A Textbook of Rheumatology. 13th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 1997.)

of th e h an d an d feet are com m on ly affected as are facets of th e cervical spin e an d tem porom an dibular join t. Th e m on oarticular or pauciarticular form of th e disease is seen in approxim ately 30% of cases. Th is is th e m ost ben ign of the form s of JRA, but the type m ost likely to presen t for the first tim e to an orth opaedic surgeon . On set of th e disease is usually in sidious an d occurs in a seem in gly oth erwisen orm al ch ild. Effusions occur m ost com m on ly in th e kn ee, followed in frequency by the elbow and the ankle. The sm all join ts are usually spared, as is th e cervical spin e. Th e pain from the pauciarticular form of JRA is m ore m anageable than other form s of the disease; over a period of 3 to 10 years, th e disease usually resolves.

History and Physical Examination A history of chronic symptom s often h elps distinguish JRA from other form s of arthritis. In fact, to m ake a true

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Figure 11.87 Arthritis of the knees and ankles in a child with

seropositive polyarticular juvenile rheumatoid arthritis. (Reproduced with permission from Herring JA. Tachdjian’s Pediatric Orthopaedics. 3rd ed. St. Louis, MO: Saunders, 2002.)

Figure 11.86 Erythematous maculopapular rash of a child with

systemic juvenile rheumatoid arthritis. This rash appeared with a fever and then faded. (Reproduced with permission from Koopman WJ. Arthritis and Allied Conditions: A Textbook of Rheumatology. 13th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 1997.)

diagn osis of JRA, sym ptom s m ust be presen t for 6 weeks. O n set of symptom s is usually in sidious with out precipitatin g traum a. Patien ts often report m orn in g stiffn ess with partial resolution of sym ptom s as th e day goes on . Patien ts sh ould also be asked about constitutional sym ptom s such as fever, m alaise, an d weigh t loss. Patients suspected of having JRA can have m any nonm usculoskeletal fin din gs on physical exam in ation ; as a result, consultation with a pediatrician and/ or rheum atologist is often warran ted. Iridocyclitis is th e m ost com m on cause of disability in th ese ch ildren (Fig. 11.88). The on set is in sidious and vision becom es impaired as a result of adh esion s an d ban d keratopathy. Frequen tly, th e ocular ch an ges m ay occur before join t in volvem en t or coin ciden t with it. Sin ce iridocyclitis is seen in 20% of children with the m onoarticular form of the disease, routine slit lamp exam in ation at 6-m on th in tervals is critical. In th e system ic form of the disease, th e abdom en should be palpated to screen for hepatosplen om egaly, and patients sh ould be assessed for lym phaden opathy. Enlarged m esenteric n odes can cause abdom inal pain that m im ics a surgical abdom en.

Ch ildren with JRA, particularly th ose with th e polyarticular subtype, sh ould h ave th eir n ecks exam in ed for C1 – C2 instability, including a careful neurologic assessm ent. Th e stretch in g of th e tran sverse ligam en t of C1 results from

Figure 11.88 The arrow points to an area of band keratopathy

just inside the corneal limbus in a girl who had anti-nuclear antibody (ANA)-positive juvenile rheumatoid arthritis. Her chronic uveitis was bilateral and had resulted in a decrease in vision to 20/400 in the right eye. (Reproduced with permission from McMillan JA, Feigin RD, DeAngelis C, et al. Oski’s Pediatrics: Principles and Practice. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)


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ch ronic synovial proliferation in the sm all bursa between the posterior aspect of the dens and the anterior surface of the transverse ligam ent. In addition, the temporom an dibular join t can be symptom atic in one-third of patients. These ch ildren frequently complain of earaches and, because of alterations in m andibular growth, h ave a m icrogn athic appearan ce. All joints in both the upper extrem ity and lower extrem ity should be system atically evaluated. Ran ge of m otion , warm th, and deform ity should be assessed. In the upper extrem ity, th e sh oulder is usually spared. Elbow m otion , however, can be m arkedly restricted an d overgrowth of th e radial h ead is frequen tly seen . Ch an ges in th e h an d begin with early fusiform swellin g of th e in terph alan geal join ts, followed by joint subluxation and th e developm ent of flexion contractures. Radial deviation of th e carpom etacarpal join t an d uln ar drift of th e fin gers are ch aracteristic. In th e lower extrem ity, loss of m otion in the hip and knee are com m on. Alterations in growth with angular deform ities an d leg len gth inequality have also been reported. Foot exam in ation often reveals in volvem en t of the subtalar joint, wh ich presen ts as a pain ful pes plan ovalgus.

Radiographs Plain radiograph s are th e m ost importan t form of im agin g, but MRI can be useful in early stages of th e disease to evaluate syn ovial hypertrophy. Classic radiograph ic ch an ges in JRAinclude sym m etric joint space narrowing, subchondral erosion s, periarticular osteopen ia (Fig. 11.89). In addition , the epiphysis m ay be overgrown from hyperem ia or undersized from growth retardation. Join t subluxation can occur in both large and sm all joints. Typical examples include uln ar subluxation of th e m etacarpoph alan geal join ts an d volar subluxation of the wrist (Fig. 11.90). In late stages

Figure 11.90 Hand radiograph in a 9-year-old girl with juve-

nile rheumatoid arthritis. Note the severe osteopenia, joint erosions, and subluxation of the first metacarpophalangeal joint. (Reproduced with permission from Koopman WJ. Arthritis and Allied Conditions: A Textbook of Rheumatology. 13th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 1997.)

of th e disease, fibrous or bony an kylosis can be seen . In th e cervical spin e, flexion –exten sion views sh ould be obtain ed to look for atlan toaxial in stability. An atlan toden s interval greater than 4 to 4.5 m m is considered diagnostic for C1 –C2 in stability. O th er radiograph ic fin din gs in clude spon tan eous fusion s of th e subaxial cervical spine and erosion of th e odontoid process (Fig. 11.91).

Figure 11.89 Anteroposterior radiograph of the pelvis of a

13-year-old girl with longstanding juvenile rheumatoid arthritis and severe joint damage. Note the osteopenia, subchondral erosions, and loss of joint space. (Reproduced with permission from Koopman WJ. Arthritis and Allied Conditions: A Textbook of Rheumatology. 13th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 1997.)

Laboratory Studies Complete blood cell counts often show low-grade anem ia and/ or leukocytosis. The platelet count, ESR, and CRP level are often elevated to a m oderate degree. Rheum atoid factor is elevated only in 10% to 15% of patients. As there is no sin gle diagn ostic test for JRA, a constellation of physical findings, radiographic changes, and abnorm al laboratory values is usually required to m ake the diagnosis. Treatment Medical treatm en t for JRA depends on the severity and type of disease. Mild, m onoarticular disease can often

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A

B

Figure 11.91 Cervical spine radiographs of a boy with

C

be m an aged with n on steroidal an ti-in flam m atory drugs (NSAIDs). For acute flares, in traarticular corticosteroid in jection s can be h elpful. In m ore severe form s of JRA, several m edication s are available in cludin g cytotoxic drugs (e.g., m eth otrexate) an d th e n ewer an ti-TNFα agen ts (e.g., in flixim ab). Alth ough effective, th ese m edication s carry a risk for side effects and should be prescribed by a rh eum atologist. Physical th erapy an d bracin g can be effective in reducin g pain , in creasin g ran ge of m otion , an d recoverin g fun ction after surgery. Surgery can be con sidered for join t con tractures, abn orm al align m en t, cervical spin e in stability, or

systemic-onset juvenile rheumatoid arthritis. (A) Note the facet joint narrowing posteriorly from C2 to C6, observed at 10 years of age. (B) At 17 years of age, the facet joints from C3 to C6 have totally fused, with complete bony ankylosis. Also note the apple-core odontoid. (C) By 21 years of age, there has been complete bony ankylosis between C2 and C3. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

join t deterioration . Syn ovectom y (eith er open or arth roscopic) can improve symptom s and prevent joint destruction. Kn ee and hip flexion contractures that impair function should be released. Growth disturbances or angular deform ities m ay require epiphysiodesis or corrective osteotom ies. Som e severely affected join ts m ay be am en able to fusion (e.g., subtalar join t). Larger join ts m ay require total join t arth roplasty. Prior to any surgical procedure, patien ts sh ould be screen ed for cervical in stability or stiffn ess th at m ay complicate in tubation . Wh en in dicated, upper cervical fusion sh ould be perform ed.


297

REGIONAL CONDITIONS Hip Perhaps n o other joint in pediatric orthopaedics h as attracted m ore attention than the hip. Several well-known pediatric diseases can affect th e im m ature h ip, in cludin g developm ental hip dysplasia, SCFE, and Legg–Calvé–Perthes disease (LCPD). Kn owledge of th e n orm al growth an d developm ent of th e h ip joint an d the vascular an atomy is essen tial for un derstan din g th e path ophysiology an d treatm en t of these conditions.

Normal Development of the Hip Th e h ip join t begin s to develop aroun d th e seven th week of gestation , wh en a cleft appears in th e m esen chym e of th e prim itive lim b bud. By th e 11th week of gestation , precartilaginous cells differentiate into a fully form ed cartilaginous fem oral head and acetabulum (Fig. 11.92). At birth, the vast m ajority of both th e fem oral h ead and th e acetabulum are cartilaginous. Th e acetabulum is composed of four differen t cartilage types. The articular surface is covered by hyaline cartilage. Con tinuous with this hyaline cartilage is th e Y-shaped triradiate cartilage, wh ich is th e acetabular physis. Th is structure con nects the three pelvic bones (ilium , isch ium , and pubis) an d allows th e acetabulum and to grow in h eigh t an d increase in depth. The fibrocartilaginous labrum surroun ds the acetabulum an d increases the depth of th e fem oroacetabular articulation (Fig. 11.93). Fin ally, epiphyseal cartilage exists on the lateral edge of th e acetabulum . This

Figure 11.92 Embryonic hip. The components of the hip joint,

the acetabulum, and the femoral head develop from the same primitive mesenchymal cells. A cleft develops in the precartilaginous cells at approximately the 7th week of gestation, defining the acetabulum and the femoral head. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Figure 11.93 Coronal section through the center of the acetab-

ulum in a full-term infant. Note the fibrocartilaginous edge of the acetabulum, the labrum (arrows), at the peripheral edge of the acetabular cartilage. The hip capsule inserts just above the labrum. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

represen ts a secon dary ossification cen ter an d is an importan t con tributor to acetabular depth an d lateral coverage. Th is lateral growth cen ter an d th e triradiate cartilage gen erally fuse by th e early teen age years. Th e ossification cen ter of th e fem oral h ead typically appears between th e fourth an d sixth m on th s of postn atal life. In itially, th is cen ter is sph erical; subsequen tly, it expan ds into an ovoid shape. The fem oral neck physis is initially con tin uous with a growth plate on th e lateral surface of th e fem oral n eck an d th e troch an teric growth plate (Fig. 11.94). Th e fem oral n eck physis an d th e troch an teric ph ysis contribute prim arily to the longitudinal growth of the proxim al fem ur; h owever, th e specific pattern of growth in all th ree physes is wh at determ ines the width of the fem oral neck, th e neck–shaft an gle, and the relationship of th e fem oral h ead to th e greater troch an ter. With in creasin g age and m echanical loading, the trabeculae becom e m ore and m ore stress oriented. By the age of 6 years, th e calcar of th e proxim al fem ur becom es prom in en t. Th e greater trochan ter initially ossifies, as a secondary cen ter, between 5 and 7 years of age. Fusion is generally complete by age 18. An important con cept is that the acetabulum and the fem oral head develop in a con cordant fashion. Proper acetabular developm ent requires a well-reduced, spherical fem oral h ead to provide th e n ecessary tem plate about wh ich to form . Th e even distribution of con tact forces supplied by a roun d fem oral h ead allows th e acetabulum to achieve an appropriate depth and coverage. Sim ilarly, the con tact pressures provided by a close-fittin g acetabulum are n ecessary to shape the fem oral h ead. Any abnorm ality of th is articulation durin g early developm en t can alter th e biom ech an ics an d result in a dysplastic acetabulum an d/ or proxim al fem ur (Fig. 11.95).

298


Figure 11.94 The proximal femur in an infant has three phy-

seal plates: the growth plate of the greater trochanter, the growth plate of the proximal femoral physis, and the growth plate of the femoral neck isthmus connecting the other two. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Vascular Anatomy Th e blood supply of th e h ip join t is critical to its n orm al developm en t. In gen eral, th e blood supply to th e hip is divided into the extracapsular circulation and th e in tracapsular circulation . Th e extracapsular blood supply of th e proxim al fem ur is predom in an tly from th e profunda fem oris artery via its two m ajor branch es: the lateral circum flex artery (LCA) an d th e m edial circum flex artery (MCA). Th ese two arteries form an extracapsular rin g aroun d th e troch an teric an d basilar n eck region s. Th e LCA supplies the anterior portion of th e rin g, whereas th e MCA supplies the m edial, posterior, and lateral portions of th e ring. Both arteries give rise to ascendin g cervical bran ches, which provide the blood supply to the fem oral n eck an d contribute to th e intracapsular circulation (Fig. 11.96). Th e m ost importan t of th ese bran ch es is th e lateral ascen din g cervical artery, a term inal bran ch of the MCA that supplies the m ajority of th e fem oral epiphysis. This artery traverses the lateral capsule in the posterior trochanteric fossa via a narrow passage and is, th erefore, vuln erable to constriction . Th e extracapsular rin g is a con stan t fin din g, alth ough its size and configuration are variable.

Figure 11.95 Untreated dislocation of the hip. Note the lack of

concave shape and the shallowness of the acetabulum due to the lack of development with a concentrically reduced femoral head. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Th e in traarticular circulation is form ed from th e four ascending cervical arteries (m edial, anterior, posterior, and lateral) that create a subsyn ovial anastom otic rin g at the m argin of the articular surface, although th is ring is often incomplete. At birth, bran ches of both the lateral and m edial circum flex arteries provide equal am oun ts of flow to th e capital fem oral epiphysis. Th e artery of th e ligam en tum teres, h owever, does not contribute significantly to th e blood supply of th e fem oral h ead. By 3 to 4 years of age, th e flow from the LCA dim inish es and supplies predom in an tly th e an terior n eck an d m etaphysis. Th e physis establish es a firm barrier between th e m etaphysis an d th e epiphysis, wh ich reduces th e con tribution s of th e m etaphyseal bran ch es. At th is poin t, th e MCA provides th e m ajority of th e blood flow to th e capital fem oral epiphysis th rough its lateral ascen din g cervical artery (lateral epiphyseal bran ch es) (Fig. 11.97). After closure of the physis, the epiphyseal an d m etaphyseal vessels again are able to form an intraepiphyseal anastom otic network. Dam age to on e or both of th e vascular system s of th e proxim al fem ur can


B

299

C

A

Figure 11.96 Extracapsular blood supply to the proximal femur.

(A) Femoral artery. (B) Extracapsular ring from the medial circumflex artery and lateral circumflex artery. (C) Ascending lateral cervical artery. (D) Physis. (Reproduced with permission from Chung SM. The arterial supply of the developing proximal end of the human femur. J Bone Joint Surg Am. 1976;58:961–970.)

Figure 11.97 By age 3 to 4, most of the blood supply to the

femoral epiphysis comes from the medial femoral circumflex artery, which gives rise to the lateral ascending cervical artery (A) and its lateral epiphyseal branches (B). A smaller contribution is provided by the medial ascending cervical artery (C). Note that by this age, the physis acts as a barrier that prevents metaphyseal vessels from supplying the epiphysis. (Reproduced with permission from Chung SM. The arterial supply of the developing proximal end of the human femur. J Bone Joint Surg Am. 1976;58:961–970.)

produce avascular n ecrosis of th e fem oral h ead an d perm anent deform ity of th e hip.

Developmental Dysplasia of the Hip DDH refers to a spectrum of path ology in th e developm en t of the im m ature h ip joint. The original term for the con dition, congenital dislocation of the hip, was replaced by the current nam e to m ore accurately reflect the variable presen tation of th e disorder and to en com pass m ild dysplasias an d frank dislocation s. The incidence of this condition is approxim ately 1 per 1,000 live births for true dislocation an d approxim ately 1 per 100 live births for dysplasia and m ild subluxation. Th ere is, however, m arked geographic an d racial variation in the inciden ce of DDH. The reported inciden ce based on geography ran ges from 1.7 per 1,000 babies in Sweden to 188 per 1,000 in a district in Man itoba, Canada. The incidence of DDH in Chinese an d African newborns is alm ost 0%, wh ereas it is 1% for hip dysplasia an d 0.1% for hip dislocation in white newborns.

Pathophysiology Although the exact etiology rem ain s un known, the fin al com m on pathway in th e developm ent of DDH is th e increased laxity of the hip capsule, which fails to m aintain a stable fem oroacetabular articulation. Th is increased laxity is probably due a com bination of horm onal, m echan ical, and genetic factors. One m ajor risk factor for DDH is fem ale gen der; the increased incidence of DDH in fem ales is thought to result from in creased susceptibility to

m aternal horm on es such as relaxin, which increases ligam entous laxity. Breech positioning, especially when the infan t’s kn ees are exten ded, h as been sh own in an im al m odels to in crease th e risk for dislocation . In h um an s, th e in ciden ce of DDH in breech in fan ts is up to 20%. Any oth er con dition th at leads to a tigh ter in trauterin e space an d, con sequen tly, less room for n orm al fetal m otion m ay be associated with DDH. These conditions include oligohydram n ios, large birth weigh t, an d first pregn an cy. Th e h igh rate of association of DDH with oth er in trauterin e m oldin g abnorm alities, such as torticollis and m etatarsus adductus, supports th e th eory th at the “crowding phenom enon’’has a role in the path ogen esis. Fin ally, gen etic factors clearly play a role. A m ajor risk factor for DDH is a positive fam ily h istory, which is present in 12% to 33% of patien ts. Twin studies h ave shown a 34% incidence of DDH in both identical twin s compared with 3% in fraternal twins. Genetic predisposition s m ost likely reflect in trin sic differen ces in collagen an d con n ective tissue laxity. Depen din g on th e severity of DDH, th e n eon atal h ip m ay be completely dislocated, partially dislocated, or m ildly displaced. Som e of these h ips probably spen d som e tim e dislocated an d som e tim e reduced. Durin g th e n eon atal period, som e of th ese un stable h ips will gradually dock in the acetabulum and will end up norm al from a radiograph ic an d an atom ic stan dpoin t. Oth er h ips will fail to reduce an d will rem ain out of th e acetabulum perm anently. Th is latter group will develop several secondary

300


Ligamentum teres Transverse acetabular ligament

Figure 11.98 The hypertrophied ligamentum teres and the

transverse acetabular ligament can block reduction. (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

an atom ic ch an ges th at can preven t reduction . Both th e fatty tissue in th e depth s of th e socket, kn own as th e pulvinar, an d th e ligam en tum teres can hypertrophy, blockin g reduction of th e fem oral h ead. Th e tran sverse acetabular ligam en t also usually th icken s, wh ich effectively n arrows th e open in g of th e acetabulum (Fig. 11.98). In addition , th e sh orten ed iliopsoas ten don becom es taut across th e front of th e h ip, creatin g an h ourglass sh ape to th e h ip capsule, which lim its access to th e acetabulum . Over tim e, th e dislocated fem oral h ead places pressure on th e acetabular rim an d labrum , causin g th e labrum to in fold an d becom e th ick (Fig. 11.99). As previously discussed, th e shape of a norm al fem oral head an d acetabulum depends on a concentric reduction between th e two. Th e m ore tim e th at a h ip spen ds dislocated, th e m ore likely th at th e acetabulum will develop abn orm ally. With out a fem oral h ead to provide a template, the acetabulum will becom e progressively shallow with an oblique acetabular roof an d a th icken ed m edial wall. Th e poin t at wh ich th ese ch an ges becom e irreversible rem ain s un kn own ; h owever, early treatm en t is preferred to m axim ize th e ch an ces for fem oral an d acetabular rem odelin g.

Classification Th e spectrum of DDH can be divided in to dislocated, subluxated, an d dysplastic h ips. Dislocated h ips are th ose in which the fem oral head no longer h as any contact with the acetabulum . Subluxation occurs wh en the fem oral epiphysis h as partially lost con tact with th e acetabulum

Figure 11.99 A coronal section of the acetabulum demonstrat-

ing the infolded hypertrophic labrum (limbus), which extends over the margin of the thickened acetabular cartilage. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

(Fig. 11.100). Radiographically, this is defined as a break in Shenton lin e (see later). Dysplasia refers to those hips that are still reduced but have shallow, saucer-shaped acetabuli. Alth ough dislocation s an d subluxation s are gen erally diagn osed early in ch ildh ood, acetabular dysplasia m ay be undetectable clinically until the patient becom es sym ptom atic durin g early adulthood.

Presentation Girls presen t with DDH m ore often th an do boys, by a 4:1 ratio. In 60% of cases, th e left side is th e affected side. In th e n ewborn period, th e m ajority of patien ts are referred because of instability found durin g routine clinical exam inations by their pediatricians. After th e walking age, ch ildren usually presen t with a lim p an d/ or leg len gth discrepan cy. For m ost ch ildren , pain is n ot a part of th e presen tin g com plain ts. In con trast, th ose patien ts with m ild acetabular dysplasia th at escapes detection durin g ch ildh ood m ay presen t in early adulth ood with groin pain an d in stability of their hip. Physical Examination In th e n ewborn period, careful physical exam in ation is essen tial for th e diagn osis of DDH. Th e ch ild sh ould be


301

B

A

Figure 11.100 Anteroposterior radiographs of the pelvis showC

exam in ed on a firm surface in th e supin e position . O bviously, the infant should be completely undressed to perform an adequate exam ination. An upset child will contract the proxim al m uscles and m ake th e diagnosis of in stability nearly impossible; it is, therefore, important to keep the ch ild relaxed by warm in g the room , providing a blanket, or feedin g with a bottle. Th e exam in er sh ould grasp th e infant’s thigh with the thum b over th e lesser troch anter m edially and the rin g or m iddle finger around the greater trochanter laterally. The Ortolani test is perform ed by gen tly abductin g th e h ip wh ile exertin g an upward force on th e greater troch an ter (Fig. 11.101). A palpable “clun k’’ represen ts th e reduction of a dislocated (but reducible) hip. The Barlow test is perform ed in th e sam e position with the hip in neutral or slight adduction an d a gentle downward force applied to the h ip joint. If the fem oral head m oves out of the acetabulum , th e hip is considered dislocatable (Fig. 11.102). These findings can be subtle and often require a delicate touch . It is importan t to distin guish th e “clunk’’ associated with a truly positive exam ination from a “click’’that is frequently reported by pediatrician s. Clicks

ing three different left hips with (A) dysplasia alone, (B) hip subluxation, and (C) hip dislocation.

A

B Figure 11.101 Ortolani maneuver: fingers up on the greater

trochanter to lift the hip into place. (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

302


A

B Figure 11.102 Barlow maneuver: palm pushes down on the

knee to push the hip out the back. (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

are usually h igh -pitch ed sn aps th at occur at th e extrem es of abduction . Th ese are usually caused by th e ligam en tum teres, fascia lata, or psoas ten don an d do n ot represen t a path ologic con dition . After approxim ately 6 weeks of age, the soft tissues aroun d th e h ip ten d to con tract m akin g th e Ortolan i an d Barlow test less reliable. At th is point, asym m etric and/ or lim ited abduction is th e m ost sen sitive in dicator for a un ilateral h ip dislocation (Fig. 11.103). An oth er useful test for diagnosing a hip dislocation is the Galeazzi test (Fig. 11.104). This test is perform ed on a flat surface with th e hips flexed 90 degrees. Un equal knee heights suggest th e presen ce of a dislocated h ip on th e sh orten ed side. Historically, asym m etric thigh folds were considered an oth er sign of DDH; h owever, th is fin din g is a com m on varian t an d does n ot reliably predict th e presen ce of a dislocation .

Figure 11.104 Galeazzi test is positive when knees are at different height. When positive, there may be a unilateral dislocated hip. (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

In th e walkin g ch ild, observation of gait will reveal a lurch from abductor dysfunction (Trendelenburg gait). In bilateral dislocation s, excessive lordosis an d h ip flexion contractures can develop (Fig. 11.105). As in th e youn ger child, unilateral dislocations will dem onstrate lim ited abduction on th e affected side an d a positive Galeazzi test. Regardless of age, care should be taken during the physical exam ination n ot to m iss a bilateral hip dislocation. Bilateral dislocations m ay be presen t without asym m etry of leg length or hip abduction. On e test that can help identify a bilateral dislocation is th e Klisic test, in wh ich th e m iddle finger is placed over the greater trochanter with the index finger on the anterior superior iliac spine. An im aginary line between th ese two fin gers sh ould poin t to th e um bilicus. In

Figure 11.103 Asymmetry of hip

abduction is associated with a unilateral dislocation in the hip that abducts less. A potential pitfall is not leveling the pelvis on the examination table; subtle asymmetry may be missed in that event. (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)


A,B

303

C Figure 11.105 (A and B) Parents of this 16-month-old girl were concerned that she was not walking correctly. She has significant lordosis and a waddling gait. (C) An anteroposterior radiograph of the pelvis demonstrates bilateral dislocated hips. (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

a hip dislocation, the greater trochan ter m oves proxim ally, causin g this line to point som ewhere between the um bilicus and th e pubis. The results of this test are unaffected by the status of the contralateral side, m aking it an extrem ely useful test wh en bilateral dislocation s are suspected.

Diagnostic Studies Because it is superior to radiograph s for evaluatin g cartilagin ous structures, ultrasonography is th e diagn ostic m odality of ch oice for DDH before th e appearan ce of th e fem oral h ead ossific n ucleus (4 –6 m on th s) (Fig. 11.106). Durin g

2 6 3 4 5

A

1

B

Figure 11.106 (A) Ultrasonography of a

C

normal newborn. (B) Anatomic drawing of hip landmarks: 1, femoral head; 2, ilium; 3, bony acetabular floor; 4, acetabular labrum; 5, joint capsule; 6, osseous rim. (C) α and β angles are identified on this normal ultrasonograph of a newborn hip. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

304


the early newborn period (0 –4 weeks), h owever, physical exam in ation is preferred over ultrason ography sin ce th ere is a h igh in ciden ce of falsely positive son ogram s in th is age group. Ultrason ography is extrem ely effective for evaluatin g th e cartilagin ous an atom y of th e h ip an d th e relation sh ip of th e fem oral epiphysis to th e acetabulum . Two differen t m eth ods h ave been popularized, an d often , both m eth ods are used on th e sam e ch ild. Th e first m eth od is the static tech nique described by Graf. The transducer is placed over th e greater troch an ter, wh ich allows visualization of th e ilium , th e bony acetabulum , th e labrum , an d the fem oral epiphysis. The angle form ed by th e lin e of the ilium an d a lin e tan gen tial to th e bony roof of th e acetabulum is term ed th e α an gle an d represen ts th e depth of th e acetabulum . Values greater th an 60 degrees are con sidered norm al, whereas those less than 60 degrees imply acetabular dysplasia. Th e β an gle is form ed by a line drawn tan gential to th e labrum an d th e lin e of th e ilium ; th is represen ts the cartilaginous roof of the acetabulum . A norm al β an gle is less th an 55 degrees; as th e fem oral h ead subluxates, th e β an gle in creases. An oth er useful test is to evaluate th e position of the cen ter of th e head compared with the vertical lin e of th e ilium . If th e lin e of th e ilium falls lateral to th e center of the head, the epiphysis is considered reduced. If the line falls m edial to th e center of the head, the epiphysis is un dercovered an d is eith er subluxated or dislocated (Fig. 11.107). Th e secon d ultrason ograph ic m eth od used in DDH is th e dyn am ic tech n ique described by Harcke. Th is tech n ique m easures th e degree of subluxation wh ile th e

h ip is bein g stressed. It is particularly useful in m on itoring the response of a h ip to brace treatm ent. Screen in g for DDH with ultrasoun d rem ain s con troversial. Although routinely perform ed in Europe, ultrasonograph ic screen in g h as n ot been sh own to be cost-effective in the Un ited States largely because of the cost associated with treatin g false-positive results. Th e curren t recom m en dation s are th at every n ewborn un dergo a clin ical exam in ation for h ip instability. Those ch ildren who have findings suspicious for DDH should be followed up with an ultrasoun d. Most auth ors agree that infants with risk factors for DDH (breech position , fam ily history, torticollis, etc.) sh ould probably be screened with an ultrasound regardless of th e clin ical fin din gs. After 4 to 6 m on th s of age, the proxim al fem ur has ossified to a sufficient degree that plain radiographs can be used to evaluate th e position of th e h ip. Prior to th is age, radiograph s m ay docum en t grossly dislocated teratologic h ips but cann ot declare a h ip as bein g located or norm al. Several classic radiographic lines have been used for m any years to assist in the evaluation of the pediatric h ip (Fig. 11.108). Hilgenreiner line is a h orizontal line through the upper m argin of the radiolucent triradiate cartilages. Perkin s line is a vertical lin e drawn from the lateral m argin of th e ossified acetabulum an d is perpen dicular to Hilgen rein er lin e. Th e in tersection of th ese two lin es creates four quadran ts aroun d th e h ip. In th e n orm al h ip, th e m edial en d of th e ossified upper fem oral m etaphysis sh ould lie m edial to Perkin line and inferior to Hilgenreiner lin e (down an d in). If the m etaphyseal beak lies outside this

Figure 11.108 Radiographic lines in DDH. Hilgenreiner’s line (H)

Figure 11.107 Coronal ultrasonographic image of a left hip that remains dislocated in spite of Pavlik harness treatment. Note that a line drawn tangential to the ilium falls medial to the center of the head.

is the horizontal line intersecting the left and right tri-radiate cartilages. Perkins’ line (P) is drawn perpendicular to Hilgenreiner’s line at the lateral corner of the acetabulum. The acetabular index (AI) is the angle between the acetabular roof and Hilgenreiner’s line and is a measure of acetabular development. The intersection of Hilgenreiner’s line and Perkins’ line creates four quadrants around the hip. In a normal, reduced hip, the medial beak of the proximal femoral metaphysis shoudl be in the lower, inner quadrant. A disruption of Shenton’s line (S) also indicates subluxation or dislocation of the hip. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)


305

Figure 11.109 The center-edge angle is the an-

gle formed between the perpendicular to a line connecting the center of both femoral heads and the line drawn between the center of the femoral head (C) and the lateral margin of the acetabulum (E). (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

quadran t, th e h ip is eith er subluxated or dislocated. Sh en ton lin e is form ed by th e m edial border of th e fem oral neck and the superior border of the obturator foram en . Norm ally, th is lin e sh ould form a con tin uous arc. By definition , in terruption of Shenton line im plies subluxation at the least, if not, fran k dislocation of th e hip. Two other radiographic m easures are frequently used to evaluate acetabular dysplasia. Th e acetabular in dex is th e an gle form ed between Hilgenreiner line and a line drawn tan gen tial to th e bony roof of th e acetabulum . In th e n orm al newborn period, th e acetabular index averages 27.5 degrees. By 6 m on th s of age, th e m ean in dex drops to 23.5 degrees, an d by 2 years of age, th e acetabular in dex is n orm ally 20 degrees or less. For in fan ts, 30 degrees is con sidered the upper lim it of norm al. After age 8 or so, the acetabular index becom es less reliable because th e triradiate cartilage becom es harder to visualize. For older children (older than 6 –8 years), th e cen ter–edge an gle can be used to assess the degree of fem oral head coverage. Prior to th is age, the fem oral epiphysis is not ossified sufficien tly to judge an accurate center point. The center–edge an gle is form ed by the in tersection of Perkins lin e an d the line drawn between the center of the fem oral head and the lateral m argin of the acetabulum (Fig. 11.109). For ch ildren 6 to 13 years of age, a n orm al cen ter–edge an gle is greater th an 19 degrees. After the age of 14, a norm al center–edge an gle is 25 degrees or greater. Values less th an n orm al in dicate un dercoverage of the fem oral head from acetabular dysplasia. In gen eral, advan ced im agin g (CT or MRI) is n ot n ecessary to m ake th e diagn osis of DDH. CT scan s, h owever, are the m ost widely used im aging m odality for confirm ing hip reduction after open or closed treatm ent of a dislocated hip. In revision cases, CT scans can also be useful to define the bony anatomy of the hip. The downsides of CT in clude radiation exposure an d th e relatively poor visualization of soft tissue structures. Upsides include th e rapid nature of the test, ease of scheduling, and widespread availability. Recently, som e authors have advocated the use of MRI to

confirm th e adequacy of reduction following treatm en t of DDH. In addition to dem on stratin g th e fem oroacetabular relation sh ip, MRI allows visualization of soft tissue structures (wh ich can poten tially block reduction ) with out th e risk of ionizing radiation . Gadolinium -enhanced MRI can also be used to assess th e perfusion of th e fem oral h ead in side th e spica cast; th is could potentially reduce the chance of avascular n ecrosis from im m obilization in an at-risk position . In young adults with acetabular dysplasia, MRI is extrem ely useful for evaluatin g th e h ealth of th e articular cartilage/ labrum and for determ ining whether a patient is a suitable can didate for h ip con servin g surgery. Arth rography is a useful in traoperative test for evaluatin g th e depth an d con cen tricity of a closed or open reduction . Poolin g of dye in th e m edial join t im plies th at th e fem oral epiphysis is not deeply seated in the acetabulum (Fig. 11.110). Poten tial blocks to reduction in clude th e ligam en tum teres, tran sverse acetabular ligam en t, pulvin ar, iliopsoas, or con stricted capsule. In addition , th e acetabular coverage can be estim ated by lookin g for the “rose thorn ’’or

Figure 11.110 Arthrogram of the left hip showing medial dye

pool after attempted closed reduction. (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, CA.)

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Figure 11.112 Newborn with bilateral hip dislocations in a Pavlik Figure 11.111 Arthrogram of a 5-year-old girl three years after

open reduction. The sharp demarcation in the dye superior to the femoral head is the “rose-thorn” sign from the acetabular labrum. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

sh arp dem arcation in the dye from the edge of the labrum (Fig. 11.111). A m ajor advan tage of arth rography is th e dynam ic n ature of the test; th e stability of reduction can be assessed in a wide variety of position s to determ in e th e optim al position for im m obilization .

Differential Diagnosis Idiopath ic DDH sh ould be distin guish ed from teratologic hip dislocations, which occur in utero. Teratologic h ips have extrem ely lim ited range of m otion and are n ot reducible on exam in ation . In gen eral, teratologic dislocation s are associated with oth er con dition s in cludin g arth rogryposis, myelodysplasia, an d a variety of gen etic syn drom es. Diagn osis is usually m ade on th e basis of th e clin ical exam in ation an d th e presen ce of oth er associated fin din gs. Th e m an agem en t of teratologic dislocation s depen ds on the specific condition and the am bulatory potential of th e ch ild. In gen eral, closed reduction is n ot successful for teratologic dislocation s. Treatment Th e treatm en t of DDH varies depen din g on th e age of the patient and the reducibility of the hip. Regardless of whether operative or n on operative m odalities are used, the goals of treatm en t are a concen tric reduction of the fem oral head into th e acetabulum , m ain ten ance of this reduction over tim e, an d avoidan ce of complication s, specifically avascular n ecrosis.

harness. Appropriately applied, the harness prevents hip extension and adduction, which can lead to redislocation, but allows flexion and abduction, which lead to reduction and stabilization. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Birth to 12 Months For in fan ts youn ger th an 6 m on th s of age with a dislocated or dysplastic h ip, a Pavlik h arn ess is th e preferred m eth od of treatm en t (Fig. 11.112). Th is soft h arn ess con sists of Velcro straps around the chest that are conn ected to stirrups around both feet. Th e anterior straps of the h arn ess can be adjusted to m aintain the hips in flexion (usually approxim ately 100 degrees); excessive flexion is discouraged because of the risk of fem oral nerve palsy. Th e posterior straps are design ed to en courage abduction . Th ese are gen erally set to allow adduction just to n eutral, as forced abduction by th e harness can lead to avascular necrosis of the fem oral epiphysis. By positioning the hips in flexion an d lim iting the am ount of adduction, the Pavlik harness poin ts th e fem oral h eads m ore directly at th e acetabulum . For dysplastic h ips, th is allows for “deepen in g’’of th e socket by encouragin g acetabular rem odeling. For dislocated hips, the harness can guide the epiphysis into the acetabulum an d m ain tain it in position while the soft tissues around the hip tighten. Newborn s h ips th at are Barlow positive (reduced but dislocatable) or Ortolan i positive (dislocated but reducible) sh ould gen erally be treated with a Pavlik h arn ess as soon as th e diagnosis is m ade. The m anagem ent of newborn s with dysplasia wh o are youn ger th an 4 weeks is less clear. A sign ificant proportion of these hips will norm alize with in 3 to 4 weeks; th erefore, m any physician s prefer to reexam in e th ese n ewborn s after a few weeks, before m aking treatm ent decisions. After applyin g a Pavlik harness, a follow-up ultrasound should be perform ed within 2 to 3 weeks to con firm h ip reduction . Harn ess treatm en t sh ould be aban don ed at 4 weeks if th e h ip is n ot reduced by th is


Figure

307

11.113 Arthrograms

demonstrate closed reduction of the developmental dysplasia of the left hip in an 8-month-old girl. (A) Untreated. (B) Reduced. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

A

tim e. Continued use of the harness beyond this period in a persisten tly dislocated h ip can cause “Pavlik h arn ess disease,’’or wearin g away of th e posterior aspect of th e acetabulum , wh ich can m ake th e ultim ate reduction less stable. For th ese h ips th at h ave “failed’’ Pavlik h arn ess treatm en t, abduction bracing can occasionally be successful in achieving a stable reduction. If the Pavlik h arn ess is successful in achievin g a reduction, the harness is generally continued un til both th e clin ical exam in ation an d th e ultrasoun d param eters (α an d β an gles) norm alize, followed by a 3- to 4-week wean in g period. For th e m ost part, Pavlik h arn ess is extrem ely effective for treatin g DDH in th e n ewborn period with reported success rates of m ore th an 90% for acetabular dysplasia an d 85% for reducible dislocation s. For th ose patien ts with persisten t in stability in spite of a Pavlik harness or th ose who present after 6 m onths of age, the next step in treatm ent is closed reduction an d spica casting. Historically, traction was used prior to closed reduction because it was th ough t th at th is decreased th e risk of avascular necrosis. Recent studies, however, have not supported this con ten tion, and the use of traction has dim inished in popularity. Closed reduction an d castin g is typically don e un der gen eral an esth esia or h eavy sedation . Arth rography is perform ed along with the procedure to confirm the adequacy of reduction (see earlier) (Fig. 11.113). Th e reduction m aneuver usually consists of hip flexion and abduction with m in im al force applied. If a reduction is felt, the hip should be evaluated un der fluoroscopy to determ in e the m ost stable position. In particular, one should assess the am ount of abduction/ adduction before th e hip redislocates. By comparing this to the m axim um range of m otion, a “safe zone’’ can be determ ined. If th e safe zone is relatively wide (i.e., close to th e m axim um ran ge of m otion), the reduction is considered stable. If the safe zone is narrow, abduction can be improved by perform ing an adductor ten otomy. Once the safe and stable position for the hip has been determ ined, th e child should be im m obilized in a bilateral h ip spica cast. Th e cast sh ould be m olded to m aintain the child in the “hum an’’ position of Salter: rough ly 90 degrees of flexion , 10 to 20 degrees of in tern al rotation , an d 30 to 50 degrees of abduction

B

(Fig. 11.114). Excessive abduction (> 60 degrees) sh ould be avoided as th is in creases th e risk of avascular n ecrosis. Because plain radiograph s are difficult to in terpret, CT or MRI is typically used to con firm reduction after cast application (Fig. 11.115). Cast im m obilization is usually contin ued for 3 to 4 m on th s, with a cast ch an ge at 6 weeks, if n ecessary. Walking Age Before 18 m on ths of age, th e preferred m eth od of treatm en t is still closed reduction an d castin g as lon g as excessive force is n ot necessary to ach ieve reduction. As children

Figure 11.114 After closed reduction, the patient should be positioned in the “human position” of flexion and moderate abduction for the spica cast. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

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A

B Figure 11.115 (A) Computed tomography (CT) scan following closed reduction of the right hip.

The hip is located as judged by a line along the anterior cortex of the pubis which intersects the proximal femoral metaphysic, the so-called CT Shenton line (thin black line). The small black arrow demonstrates the characteristic apparent posterior subluxation of the femoral head within the acetabulum, which is present even when the hip is located. The small white arrow demonstrates mediocre molding of the cast under the greater trochanter to help keep the hip reduced. The trochanteric molding on the other hip (large white arrow) is actually better in this patient. (B) This CT scan demonstrates a dislocation following attempted closed reduction and spica casting. The line along the pubis does not intersect the proximal femoral metaphysic (thin black line). There is no molding under the greater trochanter (large white arrow). (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

age, h owever, it becom es less likely th at a stable reduction can be achieved via closed m eans. Indications for open reduction of th e h ip in clude failure to obtain a stable h ip with closed reduction/ casting, unacceptable widenin g of the joint space on arthrography, and older children. One of two differen t approach es can be used to perform th e open reduction . For ch ildren between 6 and 18 m onth s of age, som e auth ors prefer th e m edial approach of Ludloff. Th e in terval for th is approach is eith er an terior or posterior to th e pectin eus. Advan tages of th is tech n ique in clude m in im al dissection and a direct approach to several of th e obstruction s to reduction (iliopsoas, tran sverse acetabular ligam en t). Disadvan tages in clude risk to th e m edial fem oral circum flex artery an d th e in ability to perform a capsulorrhaphy or concom itant pelvic osteotomy. Most auth ors prefer an an terior approach for open reduction th at is perform ed th rough th e Sm ith –Peterson in terval (ten sor fascia lata/ sartorius). Th is approach can be used in a ch ild of any age and allows for a capsulorrhaphy an d/or pelvic osteotomy to be perform ed th rough th e sam e in cision . Regardless of the approach, th e principles of open reduction rem ain th e sam e. All poten tial obstruction s to reduction sh ould be addressed in a system atic m an n er. Th ese in clude a sh orten ed iliopsoas ten don , con stricted capsule, hypertroph ic tran sverse acetabular ligam en t an d ligam en tum teres, in folded labrum , an d pulvin ar. Postoperatively, patien ts are im m obilized in a on e-an d-a-h alf–legged spica cast with the hip m ore extended and less abducted than in closed reductions.

Th e addition of a pelvic osteotomy to th e open reduction should be considered for all ch ildren older than 18 m onths. These procedures can improve th e acetabular coverage an d th e stability of th e h ip followin g open reduction . Perform in g an early in n om inate osteotomy also m axim izes th e am oun t of acetabular rem odelin g followin g open treatm ent, thereby m inim izing the risk for residual dysplasia in th e future. Th e Salter, Pem berton , an d Dega osteotom ies are th e m ost popular types of pelvic osteotom ies for DDH in walking-aged children. The Salter osteotomy is a com plete cut th rough th e ilium at th e level of th e sciatic n otch ; th e acetabulum is th en rotated forward an d outward, h in ging on the pubic symphysis. A wedge of bone graft and intern al fixation are used to m ain tain th e acetabular position . Th e Pem berton osteotomy is a curved but in complete cut in th e ilium th at h in ges on th e in tact m edial wall an d th e triradiate cartilage. Th e Dega osteotom y is an oth er in com plete transiliac osteotomy that hinges on the in tact posterom edial iliac cortex an d sciatic n otch . Th e correction from th e Dega an d th e Pem berton osteotom ies is m ain tain ed with a wedge of bone graft, but internal fixation is usually not n ecessary. All th ree procedures im prove an terior and lateral coverage of th e acetabulum , wh ich is th e area th at is prim arily deficien t in DDH. After 2 years of age, it is m ore likely that a fem oral procedure will be n ecessary in addition to th e open reduction ± pelvic osteotom y (Fig. 11.116). If excessive pressure is required to reduce the fem oral h ead intraoperatively, a fem oral shortening osteotomy should be perform ed. This


A

309

B Figure 11.116 A: Preoperative radiograph demonstrating left hip dislocation. (B) Postoperative

anteroposterior radiograph of the pelvis 1 year after open reduction, Salter osteotomy, and femoral shortening osteotomy. (Reproduced with permission from Skaggs DL, Tolo VT. Master Techniques in Orthopaedic Surgery: Pediatrics. Philadelphia, PA: Lippincott Williams & Wilkins, 2008.)

reduces th e soft tissue ten sion aroun d th e h ip, th ereby decreasin g th e risk of osteon ecrosis. Th e in dication s for con com itant derotation to correct fem oral anteversion are som ewh at controversial. Several cases have been reported of excessive derotation causin g postoperative dislocation in a posterior direction. Other authors believe that fem oral an teversion is an important part of the deform ity in DDH an d should be treated. Most authors agree, however, that varus osteotomy of th e proxim al fem ur (which was traditionally advocated) is not necessary in th e m anagem ent of DDH. Th e upper age lim it for open reduction is also con troversial. Because the likelihood of successful treatm ent decreases with advancing age an d because a dislocated hip is often painless until well into adulthood, m ost authors do n ot advocate open reduction for un ilateral dislocation s in children older than 8 years. In patients with bilateral dislocation s, issues of leg len gth discrepan cy are n ot applicable. In addition , th e ch an ces of two h igh ly successful outcom es followin g open reduction are m odest. For both of these reasons, the upper age lim it for perform in g surgery on ch ildren with bilateral dislocation s is often lowered to approxim ately 6 years of age. Residual and Late-Presenting Dysplasia Acetabular rem odeling followin g treatm en t of DDH is m ost predictable up to 4 years of age. Som e degree of rem odelin g does occur between th e ages of 4 an d 8; after th is age, h owever, th e acetabulum can n ot be relied upon to rem odel sufficien tly. In addition , m any patien ts with m ild to m oderate dysplasia m ay n ot presen t un til th eir h ips becom e sym ptom atic durin g early adulth ood. Treatm en t of residual or late-presenting acetabular dysplasia is important because un treated dysplasia can in crease th e risk of osteoarth ritis later in life. It is estim ated that 20% to 50% of all patients

requirin g total h ip arth roplasty for degen erative arth ritis h ave un derlyin g acetabular dysplasia (Fig. 11.117). Th e treatm en t of ch oice for sign ifican t acetabular dysplasia is pelvic osteotom y. Th ere are two gen eral categories of osteotom ies: recon structive an d salvage. Recon structive osteotom ies require the presence of a con centric an d con gruen t reduction . Th ese procedures can be furth er subdivided into redirection al an d reshaping osteotom ies. Redirection al osteotom ies ch an ge th e orien tation of th e acetabulum with out ch an gin g th e sh ape or volum e of th e

Figure 11.117 Anteroposterior view of the pelvis in a 15-year-

old girl with of treated developmental dysplasia of the hip as an infant. Note the bilateral acetabular dysplasia as evidenced by a steep, shallow, acetabulum and a decreased center–edge angle bilaterally. The left hip is radiographically subluxated. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

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Figure 11.118 Salter single innominate osteotomy.

Figure 11.119 Triple innominate osteotomy.

socket. All in volve a com plete tran section of the ilium plus addition al cuts in th e pelvis depen din g on th e specific tech nique. The previously described Salter osteotom y is th e sim plest type of redirection al osteotomy an d can be used in ch ildren up to 8 to 10 years of age to im prove an terolateral coverage (Fig. 11.118). For older ch ildren who lack m obility of th e pubic sym physis, a triple in n om in ate osteotom y can be effective to ach ieve greater degrees of correction . Th is procedure in volves tran section of th e ilium , th e pubis, an d the ischium but preserves the integrity of the triradiate cartilage; in tern al fixation is required to m ain tain th e position of th e acetabular fragm en t (Fig. 11.119). For older patien ts after closure of th e triradiate cartilage, th e preferred procedure is th e Gan z periacetabular osteotom y. Th is tech n ically dem an din g osteotom y in volves a com plete cut of th e pubis, a partial cut of th e isch ium an d ilium , an d a posterior colum n osteotomy that connects the ischial an d iliac cuts (Fig. 11.120). Th is osteotom y allows for sign ifican t degrees of correction but sh ould n ot be perform ed in youn ger ch ildren because it violates th e triradiate cartilage. Sin ce th e posterior colum n is preserved, th e osteotomy is quite stable an d requires on ly 3 to 4 screws to ach ieve adequate fixation (Fig. 11.121). Resh apin g osteotom ies ch an ge th e volum e an d sh ape of the socket and are, therefore, m ost useful for a capacious or sh allow acetabulum . Both th e Pem berton an d th e Dega osteotomy in volve in com plete cuts in th e ilium directed toward th e triradiate cartilage. Th e acetabular fragm en t is then bent downward, h inging on the triradiate cartilage. A wedge of bone graft is placed in th e osteotomy to m aintain the acetabular position (Fig. 11.122). By varying the direction of th e osteotomy an d th e position of th e bon e graft wedge, the increased acetabular coverage can be preferen-

tially m ade m ore an terior, lateral, or posterior. Because the bon e cuts are in com plete, th e osteotom ies are quite stable an d internal fixation is n ot necessary. For in con gruen t h ip join ts, recon structive osteotom ies cannot be perform ed and a salvage procedure m ay be necessary. Th e goal of th ese osteotom ies is to in crease th e weigh t-bearin g surface an d reduce th e am oun t of edgeloading. Because th ey do not redirect native hyaline cartilage, salvage osteotom ies rely on capsular m etaplasia to

Figure 11.120 Bernese (Ganz) periacetabular osteotomy.


A

311

B Figure 11.121 (A) Anteroposterior (AP) radiograph of the pelvis demonstrating bilateral acetab-

ular dysplasia in a 45-year-old woman. (B) AP radiograph of the pelvis after bilateral periacetabular osteotomies to improve femoral head coverage. The hardware on the right side has already been removed.

provide an articulatin g surface. Th e Ch iari osteotomy is perform ed by m aking a complete cut in the ilium just above the level of the hip joint. Th e proxim al fragm en t is then translated laterally while the acetabulum is m edialized, thereby

providin g in creased lateral coverage (Fig. 11.123). In tern al fixation h olds th e fragm en ts in place an d a spica cast is rarely necessary. The Staheli shelf procedure increases fem oral h ead coverage by building a buttress on the anterior an d lateral edge of th e acetabulum . A slot is m ade alon g th e rim of the acetabulum just above the level of th e join t, an d strips of corticocan cellous bon e are placed inside to create a “sh elf’’(Fig. 11.124). Over tim e, this shelf will rem odel an d hypertrophy from th e pressure of th e fem oral head.

Figure 11.122 The cut for the Dega acetabuloplasty is oriented

toward the sciatic notch above the level of the triradiate cartilage. The cut is incomplete and relies on hinging at the triradiate cartilage. Local bone graft wedges are used to hold the osteotomy open. (Reproduced with permission from Skaggs DL, Tolo VT. Master Techniques in Orthopaedic Surgery: Pediatrics. Philadelphia, PA: Lippincott Williams & Wilkins, 2008.)

Figure 11.123 Chiari salvage osteotomy. (Reproduced with permission from Gillingham BL, Sanchez AA, Wenger DR: Pelvic Osteotomies for the Treatment of Hip Dysplasia in Children and Young Adults. Am Acad Orthop Surg 1999;7:325–337.)

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A

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C

D

Figure 11.124 Slotted-shelf augmentation.

Slipped Capital Femoral Epiphysis SCFE is th e m ost com m on h ip disorder in adolescen ts, with an approxim ate cum ulative in ciden ce of 50 per 100,000 person s. By defin ition , a SCFE is posterior an d in ferior displacem en t of th e fem oral epiphysis in relation to th e fem oral neck (Fig. 11.125). In reality, it is the fem oral head that rem ains stationary in the acetabulum , whereas the neck displaces anteriorly and superolaterally. Early diagn osis is important because delayed or in adequate treatm ent can be a source of sign ifican t m orbidity.

Pathophysiology SCFEs are m ost likely caused by a com bin ation of m ech an ical an d en docrin e factors. Th e plan e of cleavage in m ost SCFEs occurs th rough th e hypertroph ic zon e of th e physis. Durin g n orm al puberty, th e physis becom es m ore vertically orien ted, wh ich con verts m ech an ical forces from com pression to sh ear. In addition , the hypertrophic zone becom es elon gated in pubertal adolescen ts due to h igh levels of circulating horm ones. This widening of the physis decreases the th reshold for m echanical failure. Any other factor that causes a delay in m etaphyseal ossification will also cause a relative in crease in physeal h eigh t an d m ech an ical weaken in g of th e physis. Norm al ossification depen ds on a n um ber of differen t factors in cludin g thyroid h orm on e, vitam in D, an d calcium . It is, th erefore, n ot surprisin g th at SCFEs occur with in creased in ciden ce in ch ildren with m edical disorders such as hypothyroidism , hypopituitarism , an d renal osteodystrophy. O besity, one of the greatest risk factors for SCFE, affects both the m ech anical load on th e physis an d th e level of circulatin g h orm on es. Th e com bin ation of

Figure 11.125 Pathoanatomy of the slipped capital femoral epi-

physis is demonstrated. (A) No displacement is seen. (B) Rotation of the proximal femoral neck with the femoral head (which is anchored in the acetabulum) posterior relative to the femoral neck. (C) Progressive external rotation, with progressive posterior relation of the femoral head to the femoral neck. (D) Proximal migration of the femoral neck due to the markedly posterior relation of the femoral head to the femoral neck. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

m echanical an d endocrine factors results in gradual failure of th e physis th at allows displacem en t of th e fem oral n eck in relation to the head. If th e displacem ent occurs acutely, the injury is analogous to a Salter–Harris type I fracture of the proxim al fem oral physis.

Classification Historically, SCFEs h ave been classified on the basis of ch ronology. Acute SCFEs are defin ed by hip pain for less than 3 weeks. A chronic SCFE, on the oth er hand, is one in wh ich th e symptom s h ave lasted lon ger th an 3 weeks, often for m any m on th s prior to presen tation . Ch ildren with a h istory of prolon ged h ip pain wh o presen t with a sudden increase in their symptom s are said to have an acute-onch ronic SCFE. Although easy to use, the chronologic classification h as two m ajor lim itations. First, it does not offer m uch inform ation regarding progn osis, and second, it depen ds on recall of th e patien t an d fam ily, wh ich m ay n ot be accurate. Curren tly, th e preferred classification m eth od for SCFEs is based on the stability of the slip. By definition , a stable SCFE is one in which th e child is able to walk and bear weigh t on th e affected leg with or with out crutch es. In


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con trast, an unstable SCFE is on e in which the child is un able to bear weigh t regardless of walkin g aids. Un like ch ronicity, the stability-based classification provides im portan t progn ostic in form ation . Stable slips h ave a very low rate of avascular n ecrosis; th e in ciden ce of avascular n ecrosis (AVN) in un stable slips, h owever, has been reported to be as h igh as 50%.

pain alon g th e course of th e obturator n erve. In fact, m issed or delayed diagn osis often occurs in ch ildren wh o presen t with kn ee pain and do not receive appropriate im aging of the h ip (Fig. 11.126). Unstable SCFEs usually present in an urgen t fash ion . Ch ildren typically refuse to allow any ran ge of m otion of th e h ip; m uch like a h ip fracture, th e extrem ity is sh orten ed, abducted, an d extern ally rotated.

Presentation Th e classic patien t presen tin g with a SCFE is an obese, African Am erican boy between th e ages of 11 and 16. Girls presen t earlier, usually between 10 to 14 years of age. Ch ron ic and stable SCFEs ten d to present after weeks to m on th s of symptom s. Patients usually limp to som e degree an d h ave an extern ally rotated lower extrem ity. Most patien ts com plain of groin symptom s, but isolated th igh pain or kn ee pain is a com m on presen tation from referred

Physical Examination Observation of gait in a child with a stable SCFE reveals several characteristic findings. Children typically limp and dem on strate out-toein g of th e in volved extrem ity. Th is latter fin din g is because as part of th e displacem en t, th e fem oral neck externally rotates in relation to the epiphysis. Attempts to ran ge th e h ip will reveal sign ifican t restriction s to flexion and internal rotation as the proxim al m etaphysis impin ges on th e rim of the acetabulum . In typical

A

B

C

D Figure 11.126 This 9-year-old girl presented to her primary care doctor with a 4-month history of

knee and thigh pain. Knee (A) radiographs and an anteroposterior view of the pelvis (B) were obtained but no frog lateral views. The radiographs were interpreted as normal. Two months later, the child was referred to a pediatric orthopaedist who ordered appropriate radiographs. These radiographs revealed a now moderately displaced slipped capital femoral epiphysis bilaterally (C and D). (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

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Figure 11.127 In this boy with

A

B

cases, bringing th e hip into flexion will cause obligate extern al rotation of th e h ip an d extrem ity as th e acetabulum forces the fem oral neck laterally (Fig. 11.127). This rangeof-m otion lim itation from fem oroacetabular impin gem en t can be painless at first. Over tim e, however, dam age can occur to the labrum and the articular cartilage, wh ich results in pain with flexion an d in tern al rotation of th e h ip.

Radiographs Most SCFEs can be diagn osed with an AP view of th e pelvis an d frog lateral views of both h ips (Fig. 11.128). In patien ts with an un stable SCFE, a sh oot-th rough lateral is preferred over th e frog lateral to m in im ize un n ecessary traum a to th e epiphysis from m ovin g th e leg. On e of th e earliest radio-

right slipped capital femoral epiphysis, the examination demonstrates obligate external rotation as the hip is flexed (A). No rotation with hip flexion is seen on the normal side (B). (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

graph ic fin din gs is widen in g an d blurrin g of th e physis. On the AP view, Klein line can be drawn alon g th e superior fem oral neck. Norm ally, th is line should intersect som e portion of th e lateral epiphysis. With th e typical posteroin ferior displacem ent of the epiphysis, this line will no longer touch the epiphysis. An oth er fin ding is the m etaphyseal blan ch sign , described by Howard Steel. Th is is a crescen tsh aped area of in creased density in the proxim al m etaph ysis that results from overlap of the fem oral neck an d th e posteriorly displaced fem oral epiphysis. Alth ough som e of th ese radiograph ic fin din gs can be subtle, m ost diagn oses can be readily m ade on th e frog lateral view, wh ich will reveal th e characteristic posterior and inferior displacem ent of th e epiphysis in relation to th e fem oral n eck.

A

B Figure 11.128 Radiographs of a 12 year-old-boy with 3 months of hip pain show typical findings

of a slipped capital femoral epiphysis (SCFE). (A) Anteroposterior (AP) view demonstrates physeal widening, osteopenia, decreased epiphyseal height, increased metaphyseal-teardrop distance, and asymmetry of Klein line. (B) Although many of these features are seen on the AP view, the most striking feature is how much more easily the displacement is seen on the frog lateral view. The importance of obtaining lateral views when evaluating for SCFE cannot be overemphasized. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

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Plain radiograph s are also useful for gradin g th e severity of a SCFE. The slip angle is calculated by m easuring the fem oral head –sh aft an gle of th e involved side and com parin g th is to th e n orm al, con tralateral side (if both sides are slipped, 10 degrees can be used as a n orm al value) (Fig. 11.129). Differences less than 30 degrees are considered m ild. Slip angles between 30 and 60 degrees are m oderate, an d values greater than 60 degrees are severe.

Special Studies Advanced im agin g is rarely necessary during the initial diagnosis of m ost SCFEs. Bone scans or MRI can be useful for assessing fem oral head perfusion in unstable slips and for m onitoring patients postoperatively for AVN. In addition, MRI can aid in the diagnosis of “preslips,’’a condition ch aracterized by inflam m ation of the physis that has yet to displace (Fig. 11.130). CT scan s are useful for assessin g th e severity of deform ity after initial treatm en t and for plan n ing corrective osteotom ies (Fig. 11.131).

Figure 11.129 The slip angle is the angle between the axis of the femoral shaft and the perpendicular to the base of the epiphysis. This angle (A) is generally compared with the contralateral, normal side. In this case, the left side demonstrates a mild slip, so 10 degrees may be used as normative value for comparison.

C

A

B

D Figure 11.130 A 12-year-old boy presented with pain in the right hip for 2 months. On further

questioning, he reported some vague, intermittent symptoms in the left hip. (A and B) Anteroposterior and frog lateral view of the pelvis show evidence of a right-sided slip, but no definitive signs of a left slipped capital femoral epiphysis. (C) T1- and (D) T2-weighted magnetic resonance image of the same patient demonstrate physeal widening and irregularity consistent with a “pre-slip.” (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

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Figure 11.131 Computed tomography is useful to assess the severity of residual deformity after in situ pinning and allows for a more accurate measurement of the slip angle.

Treatment O n ce th e diagn osis is m ade, th e patien t sh ould be adm itted to th e h ospital im m ediately an d placed on bed rest. Allowin g the child to go hom e prior to definitive treatm en t in creases th e risk th at a stable SCFE will becom e an un stable SCFE an d th at furth er displacem en t will occur. Children with atypical presentation s (youn ger than 10 years, th in body h abitus) sh ould h ave screen in g laboratory tests perform ed to rule out an un derlyin g en docrin opathy. The goal of treatm ent is to prevent further progression of th e slip an d to stabilize (i.e., close) th e physis. Alth ough various form s of treatm en t have been used in the past, includin g castin g and threaded pins, the current gold standard for th e treatm en t of SCFE is in situ pin n in g with a sin gle, large cannulated screw (Fig. 11.132). Screws are typically placed percutan eously un der fluoroscopic guidan ce. Th e recom m en ded position for th e screw is perpen dicular to th e physis an d in th e cen ter of th e h ead on both th e AP an d lateral views. Gen erally, 3 to 5 th reads across th e physis are sufficien t to ach ieve adequate fixation , but care sh ould be taken to en sure th at th e screw h as n ot en tered th e join t (Fig. 11.133). Because th e epiphysis is posterior an d in ferior in relation to the neck, the in itial entry poin t for the screw becom es progressively an terior on the fem oral neck with increasin g slip severity. Placing the screw too an terior, however, can in crease the ch ances th at the screw head will impin ge on th e acetabular rim . Postoperatively, m ost patien ts are allowed partial or complete weigh t-bearin g with crutches for 4 to 6 weeks. Gradual return to norm al activities en sues, with resum ption of full activity by 4 to 6 m on th s following h ip pin ning. Patients should be m onitored with serial radiographs to be sure th at th e physis is closing an d that the slip is stable. After healing from the initial stabilization , patien ts with severe deform ity m ay be can didates for a flexion , valgus, and internal rotation proxim al fem oral osteotomy to reduce impin gem en t an d improve ran ge of m otion (Figs. 11.134 and 11.135).

Th e m an agem en t of patien ts with an un stable SCFE presen ts addition al ch allen ges. Because of th e h igh risk of osteon ecrosis an d th e gross in stability of th e physis, un stable SCFEs sh ould be treated in an urgen t/ em ergen t fash ion . It rem ain s un clear wh eth er AVN is caused m ore by dam age to th e blood supply of th e fem oral epiphysis sustain ed at th e tim e of in jury or m ore by iatrogen ic traum a from reduction during surgery. Regardless, m ost authors support the gentle reduction of an unstable SCFE that occurs durin g patien t position in g. Th e un stable SCFE sh ould th en be pin n ed in situ, acceptin g wh atever residual deform ity that exists (Fig. 11.136). In general, two screws are advised to improve the rotational stability of the physis. A recent report has described increased intracapsular pressures in ch ildren with unstable SCFEs and has advocated decom pressin g th e h em atom a with in th e capsule to reduce th e risk of AVN. Un like stable SCFEs, m ost patien ts are kept n on –weigh t-bearin g postoperatively for 4 to 6 weeks, followed by a gradual return to weight-bearing. Th e in ciden ce of bilateral SCFEs is approxim ately 20% at the tim e of presentation. An additional 20% to 40% of children will develop a con tralateral slip in the future. As a result, som e surgeon s recom m en d prophylactic pin n in g of th e con tralateral side in patien ts with a un ilateral SCFE. Th e ben efits of preven tin g a possible slip m ust be balan ced with th e risks of perform in g a poten tially un n ecessary surgery. A decision an alysis, based on th e risk of con tralateral slip and incidence of complications reported in the literature, favored prophylactic pin n in g. A m ore recen t an alysis based on expected values foun d th at prophylactic pin n in g of th e con tralateral side would be warran ted if th e probability of a con tralateral slip exceeded 27%. Th e question as to wh eth er or n ot to pin th e con tralateral side rem ain s a source of con stan t debate.

Complications Ch ondrolysis, th e global loss of articular cartilage with in the hip joint, is a m ajor complication of SCFEs. With m odern treatm en t, th e in ciden ce of ch on drolysis is approxim ately 1.5%, although older studies have reported an inciden ce as high as 10%. Patients with chondrolysis typically present 1 to 4 m onths after treatm ent with extrem e pain an d loss of m otion ; radiograph s dem on strate severe join t space n arrowin g (Fig. 11.137). Th e etiology of ch on drolysis is poorly un derstood. Som e auth ors h ave sh own a correlation between tran sient penetration of the joint during surgery (by a guide pin or implant) and an increased risk of ch on drolysis. O th er reports describe th e spon tan eous developm en t of ch on drolysis in patien ts wh o have n ot been treated. The join t fluid of th ese patien ts dem on strates elevated levels of certain types of im m unoglobulins, suggestin g an autoim m une etiology. The path ologic findings include hypertrophy of the synovium , degeneration of th e articular cartilage, an d in traarticular adh esion s. Although the joint space n arrowing and range of m otion m ay recover som ewh at, m ost of th ese h ips h ave un satisfactory


A

B

C

D

E

F Figure 11.132 Proper screw locations in slips of varying severity (A and B), (C and D), and (E and F). In all three cases, the screws enter the anterior femoral neck, are perpendicular to the physis, and are located in the center of the femoral head. The starting point is more proximal and the screw is angled progressively more posterior as the magnitude of slip progresses from least (A and B) to most (E and F) severe. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

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318


Subcapital Femoral neck

Intertrochanteric

A

B Figure 11.133 A 111/ 2 -year-old boy with hip pain for 1 month

after in situ screw fixation of a stable slipped capital femoral epiphysis. Anteroposterior radiograph (A) demonstrates what appears to be adequate alignment of the hardware. The frog lateral view (B), however, demonstrates penetration of the joint surface by one screw. This case highlights the importance of keeping the screw at least 5 mm from subchondral bone even if the hip is imaged through the full range of motion at the time of surgery. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

outcom es with severe degen erative arth ritis an d join t con tractures. In th e sh ort term , sym ptom s can be m an aged with rest, gentle range-of-m otion exercises, and NSAIDs. The second importan t com plication associated with SCFE treatm en t is avascular n ecrosis (AVN) of th e fem oral head. Th e underlying cause of AVN is a disruption in th e blood supply to th e epiphysis, leadin g to devascularization of th e fem oral h ead. It is, th erefore, n ot surprisin g th at th e risk of osteon ecrosis varies with the stability of the slip. In several large series, the risk of AVN after treatm en t of a stable slip approached zero. Unstable slips, however, h ave a 15% to 50% in ciden ce of AVN. As m en tion ed, un stable slips should be treated in an urgent/ em ergen t fashion with

Subcapital (Dunn and Fish)

Femoral neck (Kramer and Barmada)

Intertrochanteric (Southwick and Imhauser)

Figure 11.134 The three levels of osteotomy to correct the

proximal deformity following slipped capital femoral epiphysis. The ability to correct the deformity is greatest with a subcapital osteotomy, least with a femoral neck osteotomy, and intermediate with an intertrochanteric osteotomy. The risk of osteonecrosis is inversely related to the distance from the physis to the osteotomy. Intertrochanteric osteotomies are the most commonly performed osteotomies because of the low rate of AVN and the ability to obtain good correction. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

gen tle reduction , secure fixation , an d capsular decompression to m inim ize th e ch an ces of developing AVN. The first radiograph ic sign of osteon ecrosis is in creased sclerosis of the epiphysis because the lack of a norm al blood supply preven ts th e n orm al resorption of bon e from disuse. Even tually, the necrotic bone is absorbed, followed by collapse of th e fem oral h ead (Fig. 11.138). Th is results in severe join t pain an d restricted ran ge of m otion . Often , th e posterior portion of th e epiphysis is relatively spared. In th ese cases, a flexion an d valgus-producing proxim al fem oral

A

C

B

D Figure 11.135 A 13-year-old girl with pain on sitting and difficulty riding a bike from impingement

and external rotation of the left leg 16 months following in situ fixation of the left slipped capital femoral epiphysis. (A) Anteroposterior (AP) pelvis and (B) lateral radiographs showing the residual deformity after in situ fixation. (C) AP and (D) lateral views 1 year after flexion–valgus–internal rotation osteotomy of the proximal femur. The osteotomy increases the neck–shaft angle, increases the articulotrochanteric distance, and moves the metaphysis away from the joint. A downside of the surgery is that if total hip arthroplasty is necessary in the future, distortion of the proximal femoral anatomy will make such a replacement more difficult. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

A

B Figure 11.136 (A) Preoperative radiograph of a left acute, unstable slipped capital femoral epiphysis. (B) Radiographs after gentle closed reduction and screw fixation with two screws. (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, CA.)

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A

B

C

D Figure 11.137 Left hip chondrolysis in a 13-year-old body. (A and B) Normal joint space of the

left hip when the patient presented with a right slipped capital femoral epiphysis. Ten months later, the patient developed a left-sided slip and was pinned in situ with prompt resolution of symptoms. However, 2 months postoperatively, the patient began to have increased hip pain, difficulty walking, and decreased hip range of motion. (C and D) Radiographs at that time reveal joint space narrowing consistent with chondrolysis. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)


Figure 11.138 Avascular necrosis of the right hip following in

situ screw fixation of an unstable slipped capital femoral epiphysis. The hardware has been removed to allow magnetic resonance imaging.

osteotom y can be useful to rotate th e relatively preserved articular cartilage into the weight-bearing zone. In severe cases, however, arthrodesis or arthroplasty m ay be the only viable option s.

Legg–Calve–Perthes ´ Disease LCPD, or idiopath ic osteon ecrosis of th e fem oral h ead, was sim ultaneously described in the literature in 1910 by Arthur Legg in the United States, Jacques Calvé in Fran ce, an d Georg Perth es in Germ any. Henning Waldenströ m of Sweden actually publish ed th e first description of th e con dition in 1909, but sin ce h e attributed th e cause to a m ild form of tuberculosis, his nam e is not frequently associated with th e disease. Sin ce its in itial description , LCPD con tinues to be on e of the m ost vexing problem s in pediatric orth opaedics, as both th e etiology an d th e treatm en t of th is con dition rem ain poorly understood.

Pathophysiology Although the underlying etiology rem ains obscure, m ost authors agree th at th e final com m on pathway in the pathogen esis of LCPD is disruption of th e vascular supply to the fem oral epiphysis, which results in isch em ia and osteon ecrosis. Several factors in th e coagulation cascade h ave been suggested to play a role in cludin g protein C, protein S, an d an tith rom bin III. Deficien cies in all th ree h ave been dem on strated in som e patien ts with LCPD, wh ich in creases blood viscosity an d th e risk for ven ous th rom bosis. Poor ven ous outflow leads to increased intraosseous pressure, wh ich in turn impedes arterial in flow, causin g isch em ia an d cell death. Although several studies support this th eory of th rom boph ilia as th e cause of vascular disruption ,

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oth er recen t studies h ave failed to sh ow defin itive abn orm alities in th e levels of fibrin olytic factors. Altern ative th eories for the cause of LCPD in clude traum a to the lateral epiphyseal vessels an d a system ic abn orm ality in growth an d developm en t (based on th e fin din gs th at ch ildren often h ave delayed skeletal growth ). Regardless of th e underlyin g etiology, the early pathologic ch an ges in th e fem oral h ead are con sisten t with isch em ia an d n ecrosis; subsequen t ch an ges result from the repair process. Waldenströ m origin ally separated th e course of the disease into four stages, although several m odification s of h is system h ave been described (Fig. 11.139). Th e in itial stage of th e disease, wh ich often lasts 6 m on th s, is ch aracterized by syn ovitis, join t irritability, an d early n ecrosis of th e fem oral h ead. Revascularization th en leads to osteoclastic-m ediated resorption of th e n ecrotic segm ent. The n ecrotic bone, however, is replaced by fibrovascular tissue an d n ot n ew bon e. Th is com prom ises th e structural in tegrity of th e fem oral epiphysis. Th e secon d stage is th e fragm entation state, which typically lasts 8 m on th s. Durin g th is stage, th e fem oral epiphysis begin s to collapse, usually laterally, an d begin s to extrude from th e acetabulum . Th e h ealin g stage, wh ich lasts approxim ately 4 years, begin s with n ew bon e form ation in th e subch on dral region . Reossification begin s cen trally an d expan ds in all direction s. Th e degree of fem oral h ead deform ity depen ds on th e severity of collapse an d th e am oun t of rem odelin g th at occurs. Th e fin al stage is th e residual stage, wh ich begin s after th e en tire head has reossified. A m ild am oun t of rem odelin g of th e fem oral h ead still occurs un til th e ch ild reach es skeletal m aturity. LCPD often dam ages th e proxim al fem oral physis; during this stage, relative overgrowth of the greater trochan ter can occur.

Classification At th e presen t tim e, th ree m ajor classification system s exist for LCPD, all of which are based on radiographic assessm ent of th e in volved hip. Th e Catterall classification system , first described in 1971, separates the disease into four groups based on the percentage of the head involved and the degree of collapse (Fig. 11.140). Catterall group I includes patients with less than 25% head involvem ent, wh ich is usually in th e an terocen tral region . Group II defines h ips with 50% head involvem ent; m ore of the anterolateral region is affected an d a cen tral sequestrum m ay be presen t. Group III patien ts h ave up to 75% of th e epiphysis affected with large areas “sequestrated.’’ Group IV describes total h ead in volvem en t. Widespread use of th e Catterall classification has waned in recent years because th e groupin gs can be difficult to defin e an d because several studies h ave dem on strated a lower interobserver reliability com pared with oth er classification system s. Th e Salter–Th ompson classification system is also based on th e percen tage of subch on dral collapse. Two groups are defined: those in group A h ave less than 50% of the

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2 mo

14 mo

18 mo

25 mo

52 mo

Figure 11.139 Legg–Calve–Perthes ´ disease with whole head involvement. Note the stages of

disease progression by month after initial presentation. Two months, initial; 14 months, fragmentation; 18 months, early healing; 25 months, late healing; 52 months, residual stage. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

head in volved, and those in group B h ave m ore than 50% of th e h ead in volved. Typically, Catterall groups I an d II represen t h ips in Salter group Aan d Catterall groups III an d IV represen t h ips in Salter group B. A m ajor drawback of the Salter–Thompson system is its relian ce on th e presen ce of a subch on dral fracture, wh ich in som e series is presen t on ly in 30% of patien ts. The lateral pillar classification , described by An thony Herrin g, has gained popularity because of its improved in terobserver reliability. Lateral pillar group Ah ips are th ose with m inim al collapse of the lateral colum n of the epiph ysis. In lateral pillar group B patien ts, up to 50% loss of height of th e lateral epiphysis can be seen . Group C describes those patien ts with m ore than 50% collapse of the lateral pillar (Fig. 11.141). Recen tly, Herrin g h as added a B/ C border group to the classification , which describes patien ts with approxim ately 50% collapse of th e lateral epiphysis. A m ajor advan tage of th e lateral pillar system is that it offers som e in form ation for predicting th e prognosis of a given hip. One difficulty with th e system , however, is th e tim in g of assessm en t. Th e origin al description classified radiographs during th e first 6 m onths of fragm en tation . Depen din g on wh en th e ch ild is evaluated durin g th e fragm en tation process, th e fin al groupin g can vary.

Presentation Th e m ost com m on presen tin g complain t is pain or a limp. Th e on set of symptom s is often in sidious, an d pain m ay be referred to th e th igh or kn ee. Paren ts m ay recall a h istory of traum a or viral illness preceding the onset of pain , an d the severity of sym ptom s m ay wax and wane in the m onths prior to presen tation . Ch ildren typically presen t between 4 an d 9 years of age, alth ough an adolescen t onset pattern h as been described. Boys are m ore com m on ly affected than girls, by a 3:1 ratio. Approxim ately 10% of patients m ay have bilateral involvem ent, although both hips rarely presen t at th e sam e disease stage. Affected ch ildren are often sm all in stature an d dem onstrate a delay in their bone age. Physical Examination Observation of a child’s gait is importan t, as a subtle limp is often th e on ly sign of early disease. Th e lim p seen in LCPD is a com bination of an an talgic gait from hip irritability and a Tren delen burg gait from abductor dysfun ction . Patien ts will gen erally h ave a positive Tren delen burg sign on th e involved side. Depen ding on the duration of symptom s, atrophy of the proxim al m uscles can be seen. Careful assessm en t of h ip ran ge of m otion is absolutely essential in the evaluation of any child with LCPD. Abduction is best


A

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B

C

D

Figure 11.140 (A) Catterall group I disease shows anterior femoral head involvement with

no evidence of sequestrum, subchondral fracture line, or metaphyseal abnormalities. (B) Catterall group II disease showing anterolateral involvement, sequestrum formation, and a clear junction between the involved and uninvolved areas. (C) Catterall group III disease shows large sequestrum involving three-fourths of the femoral head. The junction between the involved and the uninvolved portions is sclerotic. (D) Catterall group IV disease shows involvement of the whole head of the femur, with either diffuse or central metaphyseal lesions and with posterior remodeling of the epiphysis. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

m easured with the hip in extension and the pelvis well stabilized. Rotation can be assessed in eith er the supin e or pron e position . Early in th e disease process, loss of m otion m ay be m in im al but pain m ay be elicited at term inal abduction and in ternal rotation of th e hip. As the disease progresses th rough th e fragm en tation stage, loss of m otion usually worsens, especially in abduction and intern al rotation . Exten sion an d flexion is gen erally spared. As the fem oral epiphysis reconstitutes, ch ildren generally regain som e degree of m otion .

Radiographs Stan dard radiograph s for LCPD in clude an AP of th e pelvis an d frog lateral views of both hips. The radiographic fin dings in LCPD parallel the stage of th e disease. Durin g the initial stage, joint space widening an d soft tissue swellin g can be seen . Th e ossific nucleus is usually sm aller an d becom es m ore radioden se th an th e con tralateral side (Fig. 11.142). Other findings in clude m etaphyseal lucen-

cies or cysts. During th e fragm entation stage, the epiphysis becom es irregular with radiolucen cies from resorption of the n ecrotic bone (Fig. 11.143). Often, a cen tral region will becom e dem arcated from th e m edial an d lateral colum n s. Th e h ealing stage is m arked by n ew bon e form ation in the subch ondral region (Fig. 11.144). The lucent regions of th e epiphysis gradually fill in un til th e en tire h ead is reossified. Durin g th e fin al, residual stage, radiograph s will usually dem on strate th e sequelae of th e disease process: an en larged fem oral h ead (coxa m agn a), a widen ed an d sh orten ed fem oral n eck (coxa breva), an d troch an teric overgrowth (Fig. 11.145). In addition to th ese radiograph ic ch an ges, several classic radiographic signs have been reported that describe a “head at risk’’for severe deform ity. Lateral extrusion of th e epiph ysis, a h orizon tal physis, calcification lateral to th e epiph ysis, subluxation of th e h ip, an d a radiolucen t h orizon tal “V’’ in the lateral aspect of the physis (Gage sign) have all been associated with a poor progn osis (Fig. 11.146).

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A


B

C

Figure 11.141 (A) Lateral pillar type A demonstrates preservation of the height of the lateral

pillar. (B) Type B has more than 50% of the height of the lateral pillar maintained. (C) Type C has less than 50% of the lateral pillar height maintained. Recently, Herring has added a B/C subgroup to define those patients with approximately 50% collapse of the lateral pillar. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Special Studies Although not routinely used in the evaluation of LCPD, MRI offers several th eoretical advan tages. Because if its ability to defin e soft tissue an atomy, MRI can offer in form ation

about the sh ape of th e largely cartilaginous fem oral epiphysis and the congruity with the acetabulum . In addition, MRI can provide early inform ation on the extent of necrosis an d th e pattern of revascularization. On e of the m ajor drawbacks with th e curren t radiograph ic classification

Figure 11.142 The initial stage of Legg–Calve–Perthes ´ disease

demonstrates subtle widening of the joint space and increased sclerosis of the epiphysis. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Figure 11.143 Anteroposterior radiograph of the pelvis demonstrates a right hip in the fragmentation stage of Legg–Calve– ´ Perthes disease. Note the irregular radiolucencies in the epiphysis.


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Figure 11.144 Anteroposterior radiograph of the pelvis shows

a left hip in the healing stage of Legg–Calve–Perthes ´ disease. The overall contour of the femoral head is visible and the lucent areas of the epiphysis are filling in with new bone.

system s is that they rely on collapse of the epiphysis, the preven tion of wh ich is on e of th e m ajor goals of treatm en t. In th e future, MRI m ay be a better im agin g option to provide early stagin g in form ation th at can guide treatm en t geared at preventing fem oral collapse. Arthrography is the oth er special study that is frequently used to guide treatm en t in LCPD. Alth ough in vasive, arthrogram s can provide dynam ic in form ation about the sh ape of th e fem oral h ead, incongruities in the fem oroacetabular articulation , an d th e position of optim al con tain -

Figure 11.145 Adult patient with residual deformity from Legg–

Calve–Perthes ´ disease. Note the enlarged head (coxa magna), shortened neck (coxa breva), and overgrowth of the greater trochanter. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Figure 11.146 A 6-year-old boy with Legg–Calve–Perthes ´ dis-

ease of the left hip. Several Catterall “at-risk” signs are present, including a Gage sign, calcification lateral to the epiphysis, metaphyseal lesions, lateral joint subluxation, and a horizontal growth plate. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

m ent. Perhaps the best use of arthrography is to m ake th e diagn osis of h inged abduction (Fig. 11.147). Hinged abduction occurs wh en th e fem oral h ead is too large or m issh apen to rotate un der the acetabulum during abduction. In stead, th e h ead “h in ges’’on th e lateral edge of th e acetabulum ; th is leads to widen in g of th e m edial join t, wh ich is m arked by pooling of dye.

Differential Diagnosis Th e differen tial diagn osis for LCPD in cludes oth er causes of avascular n ecrosis, in cludin g traum a, leukem ia, sickle cell disease, an d h em oph ilia. An appropriate h istory an d physical exam ination will gen erally rule out these other condition s. Hypothyroidism can cause sim ilar radiograph ic findings as early LCPD; however, the findings are generally bilateral and sym m etric. In con trast, bilateral involvem ent in LCPD occurs in a sequen tial rath er than sim ultan eous fashion . In un clear cases, a thyroid fun ction panel m ay be necessary. Although radiographically sim ilar, children with MED are gen erally less sym ptom atic th an th ose with LCPD. Th ese patien ts are sh ort in stature an d alm ost always h ave abnorm alities in oth er epiphyses. In addition, both h ips are affected sym m etrically. O lder ch ildren with a h istory of DDH wh o developed iatrogenic osteon ecrosis can resem ble patien ts with LCPD. A h istory of treatm en t

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A

B

C

D Figure 11.147 A 9-year-old boy with Legg–Calve–Perthes ´ disease. (A and B) Anteroposterior and

lateral radiographs demonstrate total head involvement in the reossification stage of the disease. (C) Arthrogram in neutral position showing considerable flattening of the head. (D) Arthrogram in abduction demonstrating hinge abduction. Note the medial dye pool. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

for h ip dysplasia is generally sufficient to distin guish this diagn osis.

Treatment Treatm en t of LCPD rem ain s ch allen gin g because of th e variability in disease severity. In general, the two m ost h elpful prognostic factors are age at the tim e of disease onset an d th e lateral pillar classification . Ch ildren youn ger th an 6 years at th e tim e of disease on set, especially th ose with lateral pillar A an d B h ips, usually do well with n on operative treatm en t. Th is is due to th e greater rem odelin g poten tial of youn ger ch ildren an d th e h igh er percen tage of cartilage in th e fem oral epiphysis, which helps resist collapse. On th e oth er h an d, ch ildren with delayed on set of disease (older th an 8 years) an d lateral pillar C h ips ten d to h ave poor lon g-term outcom es regardless of treatm en t. Th ose ch ildren th at fall between th ese two extrem es (i.e., 6 –9 years of age, lateral pillar B or B/C h ips) m ay be th e best can didates for early surgical in terven tion . For n early h alf a cen tury, th e treatm en t of LCPD h as been guided by th e prin ciple of con tain m en t. Th is prin ci-

ple is predicated on th e fact th at wh ile th e fem oral h ead is fragm enting an d, therefore, in a softened condition, it is best to con tain it en tirely with in th e acetabulum ; by doin g so, the fem oral h ead will rem odel, assum ing the shape superim posed by th e acetabulum . Con versely, failure to con tain th e h ead perm its it to deform , with resultin g extrusion and impin gem en t on th e lateral edge of th e acetabulum (hinge abduction ). Essentially, the implication of the contain m en t th eory is th at th e acetabulum will act as a m old for the regenerating fem oral head. If containm en t is successful, th e en d result will be a sph erical fem oral h ead with a congruous h ip join t. Durin g th e early stages of th e disease, th e in itial goal sh ould be to alleviate discom fort and regain range of m otion. Historically, this was accomplished by a period of bed rest with or with out th e application of lon gitudin al traction. Nowadays, m ost symptom s are m anaged with th e appropriate use of NSAIDs, activity m odification , an d protected weigh t-bearin g. Som e auth ors advocate specific ran ge-of-m otion exercises, but vigorous physical th erapy sh ould be avoided as this can often exacerbate symptom s.


A

327

B Figure 11.148 An abduction orthosis. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Once range of m otion has improved, containm ent options sh ould be discussed with the fam ily. It is important to rem em ber th at to be successful, con tain m en t m ust be instituted early while the fem oral head is still m oldable; on ce th e h ead h as h ealed, reposition in g th e fem oral epiphysis will n ot aid rem odelin g an d m ay in fact worsen symptom s. Non operative con tain m en t tech n iques employ devices, wh eth er th ey be casts or orth oses, to position th e h ips in abduction and internal rotation (Fig. 11.148). In this position , th e fem oral h ead is solely con tain ed with in th e acetabulum . In 1971, Gordon Petrie reported success using two long leg casts connected by a bar. Th e legs were placed in at least 45 degrees of abduction and 10 degrees of intern al rotation . If n ecessary, an adductor ten otomy can be added to increase the am ount of abduction. These Petrie casts were chan ged every 2 m onths or so until th e fem oral head was well into the healin g stage. Orthoses such as th e Toronto brace and the Atlanta Scottish Rite brace are based on th ese sam e prin ciples of con tain m en t but allow som e degree of h ip m otion an d lim ited am bulation . Alth ough bracin g an d castin g can be h elpful for m ain tain in g m otion , recen t studies h ave n ot proven th eir efficacy for improvin g the long-term outcom e of LCPD. Surgical con tain m en t m eth ods in clude both fem oral an d pelvic osteotom ies. In the early stages of the disease, varus-producin g in tertroch an teric fem oral osteotomy

is th e m ost popular m ean s of ach ievin g con tain m en t (Fig. 11.149). Correction sh ould be lim ited to 10 to 15 degrees to m inim ize the risks of shortening the leg and causing abductor dysfunction (i.e., Trendelenburg gait). Results are best if surgery is perform ed before th e epiph ysis extrudes m ore th an 20%. Altern atively, a pelvic osteotomy can be perform ed to en h an ce lateral coverage of the epiphysis. Most com m only, a sh elf arthroplasty is the procedure of ch oice. Down sides in clude th e risk of iatrogenic impingem ent from excessive coverage an d stiffness from increased pressure on the fem oral head. Regardless of wh eth er a fem oral or pelvic osteotomy is favored, arthrography should be perform ed before the procedure to confirm th at con tain m en t is possible. After h ealin g of th e epiphysis, surgical treatm en t sh ifts from containm ent to m anaging the residual deform ity. Patients with hinge abduction or joint in congruity m ay ben efit from a valgus-producin g proxim al fem oral osteotomy (Fig. 11.150). Patien ts with coexistin g subluxation or severe lateral un coverin g m ay n eed a salvage pelvic osteotomy (e.g., sh elf arth roplasty or Ch iari) in addition to the fem oral procedure. Coxa breva and overgrowth of th e greater trochanter can be m anaged by perform ing an advan cem en t of th e troch an ter. Th is h elps restore th e len gth – ten sion relation sh ip of th e abductor m ech an ism an d can alleviate abductor fatigue. Patien ts with fem oroacetabular impin gem en t from irregularity of th e fem oral h ead can

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A

B Figure 11.149 (A) Legg–Calve–Perthes ´ disease of the left hip. (B) Two years after varus proximal femoral osteotomy. (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, CA.)

often be h elped with an osteoplasty or ch eilectomy of th e offen din g prom in en ce.

Long-Term Prognosis As m en tion ed, th e goal of containm en t is to preserve a sph erical fem oral head sin ce th e lon g-term outcom e of LCPD depen ds on th e sh ape of th e fem oral h ead. Th e Stulberg classification separates h ips in to five differen t categories based on th e radiograph ic appearan ce of th e h ip after skeletal m aturity. Stulberg group I h ips are essen tially norm al, whereas group II h ips are en larged but spheri-

cal. Stulberg group III h ips are oval or m ush room -sh aped; th ese h ips h ave an approxim ately 50% risk of developin g osteoarth ritis in adulth ood but gen erally n ot un til after th e age of 40. Stulberg group IV hips h ave an area of flattening of th e fem oral h ead but are con gruous with th e acetabulum ; patien ts with group IV deform ities h ave a greater th an 50% risk of developin g sign ifican t osteoarth ritis by th e age of 40. Fin ally, Stulberg V h ips are ch aracterized by a flatten ed fem oral h ead that is incongruous with the acetabulum . In on e series, up to 86% of th ese patien ts h ad severe degen erative chan ges by the age of 40.

A

B Figure 11.150 Same patient from Figure 11.148. (A) Arthrogram in adduction demonstrates improved congruity. (B) Valgus osteotomy was performed. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)


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volvem en t will typically dem on strate a waddlin g gait; un ilateral cases h ave an ipsilateral Tren delen burg gait. O n ran ge-of-m otion assessm en t, abduction an d internal rotation are gen erally restricted. Because of troch an teric overgrowth, abductor strength is often decreased an d patien ts typically h ave a positive Tren delen burg sign . Leg len gth s sh ould be carefully assessed; m odest discrepan cies (< 3 cm ) are n ot un com m on with un ilateral coxa vara.

Figure 11.151 Bilateral congenital coxa vara in a 3-year-old child. Note the decreased neck–shaft angle and more vertical orientation of the physis. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Congenital Coxa Vara Con genital coxa vara is an abnorm ality of the hip that results in a decreased neck–shaft an gle an d overgrowth of the greater troch an ter. Th e in ciden ce of coxa vara is m uch rarer than oth er pediatric hip condition s; 1 per 25,000 live births is gen erally affected, and the incidence does not seem to be affected by race.

Pathophysiology Con genital coxa vara m ost likely results from a prim ary defect in th e ossification of th e m edial fem oral n eck. Th e stress of weigh t-bearing causes fatigue failure of th is weaken ed region , resultin g in progressive varus deform ity of th e proxim al fem ur (Fig. 11.151). As th e n eck–shaft an gle decreases, the physis becom es m ore vertical, which converts the norm al compressive forces to shear forces. The abnorm al physeal orientation and m echanical loading pattern of a h ip with coxa vara leads to relative sh orten in g of th e fem oral neck and overgrowth of the greater trochanter. Presentation Con genital coxa vara is equally com m on in m ales and fem ales. Approxim ately 25% to 33% of cases present with bilateral in volvem en t. Patien ts with con gen ital coxa vara typically present after walking age with a painless limp. Fam ilies m ay also com plain of an apparent leg len gth discrepancy. In older children, abductor fatigue from the abnorm al m echanics of the h ip m ay cause pain with physical activity. Physical Examination Observation of gait is extrem ely importan t in suspected cases of congenital coxa vara. Children with bilateral in-

Radiographs Plain radiograph s of th e proxim al fem ur are sufficien t to m ake the diagn osis. In addition to the decreased neck–shaft angle (< 120 degrees), radiograph ic fin din gs in clude a widen ed an d m ore vertically orien ted physis, sh orten ed fem oral neck, and overgrowth of the greater trochanter. The m ost characteristic radiographic sign of congenital coxa vara is an inverted radiolucen t “V’’ in the m edial fem oral n eck th at straddles a trian gular piece of bon e. Th e superior and m ore horizontal arm of the “V’’ represents the capital fem oral physis. The inferior, m ore vertical line is the area of abnorm al ossification. In addition to the n eck–shaft an gle, th e severity of coxa vara can be graded by usin g th e Hilgen rein er epiphyseal an gle (HEA) (Fig. 11.152). Th is HEA is form ed by the intersection of Hilgenrein er line and a lin e drawn th rough th e capital fem oral physis. Ch ildren with a HEA less than 45 degrees tend to h ave spontaneous resolution of their deform ity. Values greater than 60 degrees h ave a h igh rate of progression . An gles between 45 degrees an d 60 degrees represen t a gray area; th ese ch ildren sh ould be followed closely for signs of progression . Differential Diagnosis Several other conditions can cause varus deform ity of the proxim al fem ur, in cludin g PFFD, a variety of skeletal dysplasias, an d rickets. Path ologic con dition s of bon e, in cluding OI, fibrous dysplasia, and renal osteodystrophy, can also lead to progressive deterioration of th e n eck–sh aft angle. In addition, coxa vara m ay be a long-term sequela of infection or traum a to the proxim al fem oral physis. A careful history and physical exam ination is usually sufficient to rule out these other diagn oses. Lim b deficiency syndrom es, m etabolic disturbances, and conditions with path ologic bon e gen erally affect m ore region s th an just th e h ip. Skeletal dysplasias can gen erally be distin guish ed on th e basis of fam ily h istory an d sh ort stature. Skeletal surveys can be extrem ely h elpful if th e diagn osis rem ain s un certain . Treatment For progressive cases of congen ital coxa vara, the goal of treatm ent is n orm alization of the biom ech anics around th e h ip, wh ich will h elp stim ulate h ealin g of th e path ologic fem oral n eck. To do so, one m ust restore the norm al n eck– sh aft angle, improve abductor function , and increase ran ge of m otion . As m en tion ed, surgery is recom m en ded wh en th e HEA is greater th an 60 degrees an d wh en progression

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Hilgenreiner line

B

A Figure 11.152 Hilgenreiner epiphyseal angle (HEA). (A) The HEA is the angle between Hilgenreiner line and a line drawn parallel to the capital femoral physis. (B) An HEA angle of 68 degrees in a patient with coxa vara; this value is associated with a progressive deformity. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

is docum en ted in ch ildren wh ose HEA is between 45 degrees an d 60 degrees. Valgus osteotom y of th e proxim al fem ur is the m ost popular surgical techn ique for correctin g con gen ital coxa vara. Perform ed at eith er th e in tertroch an teric region or th e subtroch an teric region , valgus osteotomy corrects th e n eck–shaft angle, lowers th e

trochan ter, improves abduction, and corrects the orientation of th e physis (Fig. 11.153). Several osteotomy techn iques h ave been described, but fixation usually consists of a blade plate or screw an d side plate device. Correction of th e HEA to less th an 40 degrees h as been associated with a decreased risk of recurrence.

A

B Figure 11.153 (A) Anteroposterior (AP) view of the pelvis showing bilateral congenital coxa vara. (B) AP view of the right hip 1 year after valgus-producing intertrochanteric femoral osteotomy.

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KNEE AND LEG

Osteochondritis Dissecans

Osgood–Schlatter Disease

Osteoch ondritis dissecans is an osteochondral lesion th at typically occurs in the distal fem ur. Although the exact etiology rem ain s un kn own , m ost auth ors believe th at som e sort of vascular insult causes osteon ecrosis of the subchondral bon e th at leads to weaken in g of th e overlyin g articular cartilage. Th e m ost com m on location is th e lateral aspect of the m edial fem oral con dyle, although lesion s can also occur in th e lateral fem oral con dyle, troch lea, or patella. Ch ildren usually present in their preadolescent or adolescent years with either chronic knee pain or acute knee pain after a traum atic even t. Depen din g on th e stability of th e lesion , ch ildren m ay complain of m ech an ical symptom s (lockin g, catchin g, popping, etc.). Physical exam in ation will often reveal direct tenderness over the site of involvem en t, and ran ge of m otion m ay be restricted. Unless th ere is precipitatin g traum a, m ost kn ees do n ot dem on strate an effusion . Plain radiographs (including a tunnel view) are usually adequate to m ake th e diagnosis (Fig. 11.154). However, MRI scan s are h elpful to determ in e th e stability of th e lesion an d to m onitor healin g after treatm ent (Fig. 11.155). Several classification system s exist for osteoch on dritis dissecan s, but m ost differen tiate lesion s based on stability of th e osteoch on dral fragm en t. Type I lesion s are con sidered stable an d h ave in tact cartilage on th e surface of th e join t. Type II lesion s m ay h ave som e fissurin g, but th e osteoch on dral fragm en t is still attach ed to th e base by an osseous bridge. Type III lesion s are com pletely detach ed

Osgood –Sch latter disease is really m ore appropriately con sidered a condition rather than a disease. This con dition is an osteoch ondrosis of the tibial tubercle. Unlike epiphyses, wh ich are loaded in compression , apophyses are loaded in ten sion . In th e case of Osgood –Sch latter disease, th e pull of th e stron g quadriceps causes a traction apophysitis at the tibial tubercle. This low-grade in flam m atory condition results from ch ron ic m ech an ical overload an d causes localized pain and swelling. Th e typical ch ild with Osgood –Schlatter disease presents in the preadolescent or adolescent years complaining of anterior knee pain. These children in variably localize their pain to th e tibial tubercle. Ch aracteristically, th e pain is m ade worse by strenuous physical activity and stair clim bing. Although the diagn osis is rarely in question based on the clin ical evaluation alone, m ost physicians will obtain radiograph s of th e kn ee. Radiograph ic fin din gs in clude irregular ossification of th e tibial tubercle an d traction osteophytes. Th e treatm en t of O sgood –Sch latter disease focuses on activity m odification since symptom s are prim arily activity related. Moderation of activity and the selection of on e sport versus m any is usually th e m ost help. Adjunctive therapy with icing after activity, ligh tweight knee straps or braces, an d in term itten t NSAID adm in istration are all of value. In severe cases in which an ossicle is presen t, surgical excision can be con sidered.

A

B Figure 11.154 (A) Tunnel view of the left knee showing a loose body from a detached osteochon-

dritis dissecans (OCD) lesion. (B) Lateral view confirms the loose body. (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, CA.)

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A

B Figure 11.155 (A) Magnetic resonance image of a knee demonstrating an OCD lesion (black

arrow) in the classical location (lateral aspect of the medial femoral condyle). The lesion appears to be stable, with an intact articular surface. (B) Lateral image of the same knee (black arrows outline lesion). (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

but are n on displaced, an d type IV lesion s are completely displaced. Treatm en t of osteoch on dritis dissecan s depen ds on th e stability of th e lesion and th e age of the patient. Children with an open distal fem oral physis are considered to h ave juven ile osteoch on dritis dissecan s; th ese youn ger patien ts ten d to h ave h igh er h ealin g rates with n on operative treatm en t. As a result, con servative m an agem en t in th e form of activity restriction an d/ or cast im m obilization sh ould be tried for at least 6 m on th s for all stable lesion s. Th ose that fail nonoperative m anagem ent can be treated with arth roscopic debridem en t an d m icrofracture. After skeletal m aturity, patien ts are m ore likely to fail con servative treatm en t an d require surgery. For un stable lesion s, regardless of age, arth roscopic fixation usin g h eadless screws or bioabsorbable implan ts is in dicated.

Popliteal Cysts Popliteal cysts are synovial cysts located behind the knee join t th at are typically composed of gelatin ous m aterial. Prim ary cysts arise from th e bursa un der th e m edial h ead of the gastrocnem ius or from the fascia of the sem im em branosus m uscle. Secon dary cysts com m un icate directly with the knee joint and usually in dicate an intraarticular process such as a m eniscal tear or synovitis. Whereas the m ajority of popliteal cysts in adults are secon dary to in traarticular disease, m ost cysts in ch ildren are a prim ary ph en om en on . Ch ildren typically presen t with a pain less m ass beh in d the knee. Parents m ay report that th e m ass waxes or wanes in size. Plain radiograph s can be used to rule out oth er conditions, but clinical exam ination and transillum ination

of th e cyst are gen erally sufficien t to m ake th e diagn osis. In certain cases, ultrason ography can be h elpful to distin guish cysts from solid tum ors. MRI is gen erally n ot n ecessary but m ay be indicated in am biguous cases. Th e vast m ajority of popliteal cysts will resolve with in 6 m on th s. Th erefore, m ost cysts sh ould be treated con servatively with warm th, compressive bandages, and NSAIDs (if necessary). Surgical excision should be avoided unless th e m ass fails to resolve, en larges rapidly, or causes sign ificant symptom s.

Discoid Meniscus A discoid m eniscus is an abnorm ally large an d abn orm ally sh aped m en iscus that usually occurs in the lateral h em ijoin t. Th e etiology of th e discoid m en iscus rem ain s con troversial. The theory of em bryologic delay has been popular for m any years. Simply stated, this proposes that the norm al “C’’ shaped m eniscus is th e result of differen tial changes that occur in an initial “hockey-puck’’ shaped structure. Current literature, h owever, h as suggested that this m ay not be th e cause sin ce discoid m en isci h ave n ever been reported in the autopsies of newborns or stillbirth s. A discoid m en iscus can presen t anywh ere between th e age of 3 and early adulth ood. Young children generally do n ot complain of pain but m ay presen t with a limp, interm itten t effusion s, or a loud clun k with flexion an d rotation al m otions of the knee. As the ch ild grows older, the m eniscus can tear, resulting in pain, lockin g, and other m echanical sym ptom s. Physical exam ination m ay reveal pain along the lateral joint line and lack of term inal extension. Gait is notable for a persisten t kn ee flexion th rough stan ce ph ase.


333

Figure 11.156 Three successive sagittal magnetic resonance image cuts demonstrating contiguous anterior and posterior horns of the lateral meniscus. This finding is diagnostic of a discoid meniscus. (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, CA.)

Radiograph s are of lim ited utility; occasion ally, squarin g of th e lateral fem oral con dyle can be seen . MRI, h owever, is extrem ely useful in evaluatin g m eniscal an atomy. Eviden ce of con tiguous an terior an d posterior h orn s of th e lateral m eniscus on three successive sagittal plane cuts is diagn ostic (Fig. 11.156). Discoid m en isci can be classified in to th ree types: com plete, in complete, an d Wrisberg varian t. Th is latter type is really n ot an abn orm ality in m en iscal sh ape but rath er an

abn orm ality in th e periph eral attach m en t of th e m en iscus. A complete absen ce of th e m en iscotibial ligam en ts m akes the Wrisberg type hyperm obile and prone to tearing. Asymptom atic patien ts do n ot require treatm en t. Patien ts wh o com plain of pain or m ech an ical sym ptom s sh ould undergo arth roscopic treatm en t. If possible, only the cen tral portion of the discoid m eniscus should be rem oved (saucerized) to preserve som e m en iscal fun ction (Fig. 11.157). Occasion ally, th e m en iscus too is dam aged

A

B Figure 11.157 (A) Complete discoid meniscus viewed from the lateral compartment. (B) Appearance of the meniscus after arthroscopic saucerization. (Reproduced with permission from Skaggs DL, Tolo VT. Master Techniques in Orthopaedic Surgery: Pediatrics. Philadelphia, PA: Lippincott Williams & Wilkins, 2008.)

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an d th e en tire m en iscus m ust be resected. Un stable discoid m en isci, in cludin g th e Wrisberg type, can be stabilized by suturin g the edge to the capsule.

BLOUNT DISEASE (TIBIA VARA) Pathophysiology Blount disease, or tibia vara, is an abn orm ality in the m edial aspect of th e proxim al tibial epiphysis an d physis th at results in progressive varus deform ity of th e tibia. Th e term Blount disease really applies to two distin ct condition s: in fan tile tibia vara an d adolescen t tibia vara. Th e true etiology of both con dition s rem ain s poorly un derstood. Infantile tibia vara h as not been reported at birth an d is, th erefore, con sidered a true developm en tal con dition . Th e etiology is con sidered m ultifactorial, but early am bulation an d African Am erican h eritage both are risk factors for developing tibia vara. As part of the condition, dam age occurs to th e m edial physis of th e proxim al tibia th at results in progressive bowin g of th e tibia from relative overgrowth of th e lateral side. Histologic studies h ave dem on strated disorgan ization of th e physis an d a disruption of th e n orm al en doch on dral ossification process. In later stages, a true bony bridge can form across th e m edial physis th at preven ts any rem ain in g growth on th e m edial side. Adolescent tibia vara occurs wh en the tibial physis is m ore m ature. Repetitive m icrotraum a from compressive loads is th ough t to cause retardation of th e growth of th e m edial physis. Th is th eory is con sisten t with th e h igh prevalen ce of obesity in children with adolescent tibia vara. Histopath ologically, fissures and clefts can be seen in the physeal cartilage an d are h igh ly suggestive of repetitive m icroin jury. Un like in fan tile tibia vara, bony bridges are rarely seen .

Classification As m ention ed, Blount disease is typically separated into in fan tile an d adolescen t form s on th e basis of th e age of on set. Th e severity of in fan tile tibia vara is described by the Langenskiö ld classification (Fig. 11.158). Th e classification is based on the radiographic appearance of th e proxim al tibia. Th e con dition of th e growth plate, th e exten t of

I

II

III

IV

V

VI

Figure 11.158 The six stages of radiographic changes seen in Langenskiold ¨ classification of infantile tibia vara. (Reproduced with permission from Langenskiold ¨ A. Tibia vara. Clin Orthop Relat Res. 1989;246:195.)

Figure 11.159 Clinical appearance of a 30-month-old girl with

right-sided Blount disease. The left side, in contrast, demonstrates physiologic bowing. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

the m edial beaking, changes in the m edial tibial m etaphysis, and evidence of prem ature fusion of the growth plate m edially are all factors in differentiating th e grades. The stages represen t progressive m edial physeal inclination of the proxim al tibia with physeal bar presence in stage 6. The Lan genskiö ld grade and the age of the patient are factors in determ in ing treatm ent.

Presentation and Physical Examination Patients often present with the characteristic appearance of sign ifican t gen u varum (Fig. 11.159). Patien ts with infan tile-onset types typically have bilateral involvem ent, wh ereas adolescen t-on set disease is usually un ilateral. Most patien ts are asymptom atic, but som e adolescen ts m ay report ach in g pain on th e m edial aspect of th eir kn ee. Th e m ajority of patients, regardless of th e age of presentation, are significantly obese, with weigh ts that are often greater th an the 95th percen tile for age (Fig. 11.160). During the physical exam in ation , careful atten tion sh ould be paid to the child’s gait. Eviden ce of a “lateral thrust’’(lateral translation of the tibia under the fem ur) with weight-bearing is usually in dicative of Bloun t disease. In ternal tibial torsion is often presen t in addition to th e varus deform ity. A con com itant leg length discrepancy can be seen in ch ildren with un ilateral disease.


335

Figure 11.160 A 13-year-old boy with adoles-

cent Blount disease. As is often seen in this group of patients, he is morbidly obese. The large thigh circumference in such patients contributes to the deformity and increased load across the medial distal femur and proximal tibia. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

A

B

Imaging Radiograph ic evaluation in cludes views of th e proxim al tibia and a standing AP view of both hips to an kles, with the patellas (not the feet) facing forward. The characteristic radiograph ic fin din gs in in fan tile tibia vara in clude varus an gulation of the proxim al tibial epiphysis/ m etaphysis, widen in g an d irregularity of th e m edial tibial physis, a m edially sloped epiphysis, an d prom in en t beakin g of m edial m etaphysis. Prior to the appearan ce of these findings, it can be difficult to distin guish in fan tile Bloun t disease from severe physiologic bowing. For these cases, Levin e and Drennan described the m etaphyseal–diaphyseal an gle (MDA) to h elp predict th e likelih ood of a given lim b developin g infantile Bloun t disease. A ch ild with an MDA of less than 9 degrees is un likely to progress to tibia vara, wh ereas th e one with greater th an 16 degrees is at h igh risk for progression (Fig. 11.161). Unlike the infantile form , the sh ape of the tibial physis is relatively norm al in adolescent Blount disease. Slopin g of th e m edial epiphysis an d beakin g of th e m etaphysis are not usually seen . The hallm ark of adolescen t tibia vara is widening of the m edial physis. Occasionally, widening of the physis can also be seen in th e lateral side of the distal fem ur. Advan ced im agin g, such as CT scan or MRI, is gen erally n ot n eeded to m ake th e diagn osis of Blount disease. In certain cases, th ese studies m ay be useful to rule out th e presen ce of a bony bar an d to evaluate th e health of the m edial physis.

Differential Diagnosis Th e m ost importan t diagn osis to distin guish from Bloun t disease is physiologic gen u varum , wh ich can be a difficult

Figure 11.161 Standing radiograph of the same patient from

Figure 11.159. The metaphyseal–diaphyseal angle on the right is 20 degrees, compared with 10 degrees on the left. This is consistent with stage II Blount disease on the right and physiologic bowing on the left. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

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Figure 11.162 (A) Anteroposterior (AP) ra-

A

task in a ch ild youn ger th an 2 years. Th e lack of ch aracteristic “Bloun t fin din gs’’on radiograph s an d a low MDA is in dicative of physiologic gen u varum . In addition , th e deform ity in physiologic gen u varum is sym m etric an d global, often involving both th e fem ur and the tibia. However, the presen ce of a focal deform ity or a lateral thrust during gait is m ore suggestive of Blount disease. O th er n onphysiologic causes of gen u varum in clude skeletal dysplasias, rickets, traum a, an d in fection.

B

diograph showing focal changes of Langenskiold ¨ stage IV infantile Blount disease. The medial tibial physis is indistinct and concerning for a physeal bar. A follow-up computed tomography scan showed a bridge of bone across the medial physis. (B) AP and lateral radiographs after bar excision and proximal tibial osteotomy. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

with closed physes, a valgus producin g proxim al tibial osteotomy with in tern al fixation is th e m ost com m on ly used approach. Alternatively, external fixation using a circular or m ultiaxial fram e can be used to achieve gradual correction of th e deform ity an d to m in im ize th e risk of n eurovascular com plication s from an acute correction .

Treatment Treatm en t is guided by both th e age of th e patien t an d the severity of th e condition . Observation m ay be in dicated wh en the diagnosis is still uncertain, but treatm ent sh ould be initiated as soon as th e radiograph ic diagn osis of in fan tile Bloun t disease is con firm ed sin ce early treatm en t h as been associated with a better progn osis. A brace, such as a valgus-producing KAFO , can be effective in treatin g m ild to m oderate in fan tile tibia vara (Lan gen skiö ld II or better) before 3 years of age. For older ch ildren , patien ts with m ore severe disease, and those wh o do n ot respon d to bracin g, surgery is recom m en ded. Th e results of corrective osteotomy are best if surgery is perform ed by 4 years of age. Various techn iques have been described, including transverse, dom ed, an d an gled osteotom ies, but in all cases, th e lim b sh ould be overcorrected in to valgus to m in im ize th e risk of recurrence. The internal tibial torsion sh ould also be corrected. In m ore severe Lan gen skiö ld stages, con sideration sh ould be given to resection of th e m edial bar an d in terposition of fat or oth er m aterial to reduce th e ch an ces of recurren t deform ity (Fig. 11.162). For ch ildren with adolescen t Bloun t disease an d open physes, tem porary h em iepiphysiodesis usin g a staple or plate or a m ore perm an en t lateral h em iepiphysiodesis can be used to gradually correct the deform ity over tim e (Fig. 11.163). For severe deform ities an d for th ose patien ts

A

B

Figure 11.163 (A) Long-cassette radiographs of a teenager with unilateral adolescent Blount disease and open physes. (B) Hemiepiphyseal stapling was used. Correction is noted 1 year after staple insertion in the lateral distal femur and proximal tibia. This technique is optimal in mild to moderate deformities, in which 1 to 2 years of growth remain. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)


ANTEROLATERAL BOWING AND CONGENITAL PSEUDARTHROSIS OF THE TIBIA Pathophysiology Anterolateral bowing of the tibia is, as the nam e implies, an abnorm al bow of the tibia with an apex th at is anterior an d lateral. This deform ity renders the tibia susceptible to fracture and is closely associated with the developm ent of a pseudarth rosis at th e fracture site (Fig. 11.164). In reality, anterolateral bowing of the tibia an d th e subsequent CPT should be considered a continuum . It is a rare condition, occurring in 1 per 100,000 live births, and is unilateral in th e vast m ajority of cases. Its etiology rem ain s unclear. Several th eories h ave been proposed, in cludin g in trauterine traum a, gen eralized m etabolic disease, and vascular m alform ation. The fibula is affected in approxim ately on ethird of patients. Histologically, there is a th ickened periosteum an d a cuff of abn orm al, h igh ly cellular fibrovascular tissue at the site of the pseudarthrosis. Neurofibrom atosis (NF) is th e m ost com m on ly associated condition. Approxim ately 6% of patients with NF type I develop deform ity of the tibia, whereas up to 55% of

A

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case of anterolateral bowing and pseudarthrosis are associated with NF. Other associated con ditions include Ehler– Dan los syn drom e, fibrous dysplasia, an d am n iotic ban d syn drom e.

Classification Num erous classification system s of CPT h ave been described, includin g th ose of Boyd, Anderson , and Crawford. Radiographic classification of CPT as described by Crawford is as follows: type I has anterolateral bowin g with m edullary sclerosis and cortical thickening at the apex; type II h as con striction or n arrowin g of th e cortical diam eter with cortical sclerosis; type III h as a cystic-appearin g lesion ; type IV h as frank pseudarth rosis with tapered bone en ds (Fig. 11.165). Th ese system s gen erally describe th e radiograph ic appearan ce of th e un treated bon e at th e pseudarth rosis site, th e presen ce of fracture at birth , an d th e appearance of the fibula. However, none of these classification system s provides specific guidance for m an agem ent or is predictive of outcom e. Also the type of CPT in th ese classification system s will change with growth. Consequently, th e criteria th at m ay be m ost relevan t to treatm en t were suggested by Joh nston an d are based on the presence or

B

Figure 11.164 (A) Anterolateral bowing of the tibia may be apparent at birth or may progress with weight-bearing. Bowing usually occurs between the middle and distal third of the tibia. (B) Even though this deformity was protected in a total-contact orthosis, fracture and pseudarthrosis developed at the apex of the bow. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

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crease in distal tibia growth , results in shorten ing of the lim b. Usually, the disease becom es eviden t during th e first year of life, but m ilder form s m ay m anifest later, up to age 12 years. Th e deform ity is an apical prom in en ce in th e leg laterally with the foot inverted or m edially displaced relative to the lower leg. If fracture has already occurred, m otion at the pseudarth rosis site is appreciated. Mild deform ity m ay presen t as a limp because of shortening or impendin g fracture. The foot on th e involved side m ay be norm al or sligh t sm aller th an the contralateral foot.

Imaging

Figure 11.165 Crawford classification for congenital pseu-

darthrosis of the tibia. Type 1: anterolateral bowing with medullary sclerosis. Type II: “failure of tabulation with constriction or narrowing of the cortical diameter. Type III: cystic lesion. Type IV: frank pseudarthrosis with tapered bone ends. (Reproduced with permission from Johnston CE. Congenital pseudarthrosis of the tibia: results of technical variations in the Charnley-Williams procedure. J Bone Joint Surg Am. 2002;84:1799–1810.)

absen ce of fracture an d th e age at wh ich th e first fracture occurs (early on set before age 4 years an d delayed on set after age 4 years).

Presentation and Physical Examination CPT is ch aracterized by an terolateral an gulation of th e tibia (Fig. 11.166). This bowin g, com bin ed with an overall de-

AP and lateral views of the tibia dem on strate anterolateral bowin g of th e tibia. Th e site of pseudarth rosis m ay appear dysplastic with diaphyseal n arrowin g, sclerosis an d even obliteration of th e in tram edullary can al, or m ay appear cystic. Most of the lesion s are localized to the m iddle or distal th ird of th e tibia. However, th e location m ay ch an ge durin g th e course of th e disease. MRI m ay defin e th e exten t of periosteal th icken in g an d path ology. In Crawford types I, II, an d IV, th e pseudarth rosis appears hypoin ten se on T1weigh ted im ages. In Crawford type III patien ts, th e pseudarth rosis appears sligh tly hyperin ten se. In all patien ts, the lesion appears hyperintense on T2-weighted an d fatsuppressed im agin g.

Differential Diagnosis Bowing of the tibia can occur in various plan es with th e apex of the deform ity defining the direction of bowing. Anterolateral bowing as seen in CPT should be distinguished from posterom edial and anterom edial bowing of the tibia. Posterom edial bowing is associated with calcan eovalgus feet and gen erally resolves with growth . Anterom edial bowin g, on th e oth er h an d, is associated with fibular h em im elia.

Treatment

Figure 11.166 Clinical photographs of a child with anterolateral

bowing and congenital pseudarthrosis of the tibia. The extremity is shortened, and the apex of the deformity is anterior and lateral. (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, CA.)

Treatm ent of anterolateral bowing an d CPT is ch allenging. Prior to fracture, an terolateral bowin g of th e tibia is best m anaged with a brace such as a clam shell AFO or KAFO. Th is is th e best m ean s of protectin g th e bon e, m in im izin g the risk of fracture, and con trolling the deform ity. Certain authors have suggested that surgery can be considered in patien ts with an terolateral bowin g to preven t fracture; th is usually con sists of an allograft or autograft fibular strut, wh ich is used to bypass th e region of at-risk bon e. Un fortun ately, m ost patients present after a fracture has already occurred and an established pseudarthrosis is already presen t. For th ese patien ts, surgical in terven tion attempts to repair th e pseudarth rosis an d preven t progressive deform ity. Th e appropriate age for surgical in terven tion is not known . The basic tenets of the surgical treatm ent


A,B

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C,D Figure 11.167 (A and B) Preoperative anteroposterior and lateral radiographs of the tibia demonstrating congenital pseudarthrosis and anterolateral bowing. (C and D) Postoperative radiographs 2 months after bone grafting and intramedullary fixation of the tibia and fibula. (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, CA.)

of CPT in clude resection of th e pseudarth rosis, biologic bon e bridgin g of th e defect, stable fixation , an d correction of angular deform ity. The highest rates of union h ave been reported after surgical in terven tion alth ough n o sin gle m ethod of surgery has proved to be superior. In tram edullary stabilization is often recom m en ded as the first line of surgical treatm ent. Several intram edullary nail designs, including telescoping n ails, fixed-length n ails, an d th e William s nail, have been used to treat CPT (Fig. 11.167). All of th ese intram edullary devices provide load sh arin g an d reinforcem en t of the bone long after th e pseudarth rosis h as been treated. Rin g extern al fixators are som etim es used when a sign ifican t lim b length discrepancy is also present: th e pseudarthrosis is resected an d the gap is compressed, whereas a corticotomy is perform ed at a separate proxim al site for distraction osteogenesis. Oth er con com itant m odalities include contralateral vascularized fibular graft an d bon e m orph ogen ic protein . Com plications of surgical treatm ent include refracture, persisten t pseudarth rosis, residual deform ity, an kle valgus deform ity, an d residual lim b len gth discrepancy. The need for fibular surgery rem ain s controversial. Som e studies show that wh en th e fibula is in tact, fibular osteotomy is n eeded for optim al lim b align m en t an d un ion . Fin ally, m ultiple un successful attempts to m aintain union or lim b align m ent, significant lim b len gth discrepancy (> 5 cm ), a perm anently deform ed foot, or function al loss are relative indications for an amputation. The Sym es amputation offers excellen t fun ction . In som e cases, am putation at th e pseudarth rosis is n ecessary.

IDIOPATHIC TOE-WALKING Alth ough it is n ot un com m on for toddlers to toe-walk, lack of n orm al h eel strike after 3 years of age is abn orm al. Typically, toe-walking starts as a habitual phenom en on , an d wh en asked to m ost ch ildren , th ey are able to walk plan tigrade. O ver tim e, h owever, a con tracture of th e h eel cord can develop, wh ich m akes th e gait disturban ce m ore difficult to con trol. Patients typically present between 3 and 4 years of age. Most patients are asymptom atic, but som e children m ay com plain of fatigue or pain in th e gastroc-soleus com plex. Idiopath ic toe-walkin g is m ore com m on in m ale ch ildren , and a fam ily h istory of the condition can often be elicited. Th e toe-walkin g gait is best appreciated with th e ch ild barefoot. As m en tioned, if the ch ild con centrates, th e degree of toe-walking can often be con trolled. If distracted or asked to run, however, the true severity of the gait disturbance is revealed. Ankle plantar flexion is generally norm al, but dorsiflexion sh ould be carefully evaluated to determ in e th e degree of h eel cord tigh tn ess. Toe-walkin g is often a sign of m ore serious conditions such as CP, prim ary m uscle disease, an d disturban ces of th e CNS. As a result, th e diagn osis of idiopath ic toe-walkin g sh ould be m ade on ly after th ese oth er con dition s h ave been ruled out. Un like th ese oth er diagn oses, ch ildren with idiopath ic toe-walkin g h ave n orm al m uscle ton e and m uscle stren gth; spasticity and clonus are absent. Treatm en t gen erally con sists of h eel cord stretch in g to m aintain range of m otion and an articulated AFO with

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a plan tar flexion stop to preven t th e toe-walkin g an d en courage norm al h eel strike gait. For patients with tight heel cords who lack significant m otion, serial stretch ing casts m ay be n ecessary to regain sufficien t an kle dorsiflexion . If toe-walkin g persists in spite of m axim al con servative treatm en t, surgical len gth en in g of th e gastrocn em ius sh ould be considered.

FOOT AND ANKLE Metatarsus Adductus Metatarsus adductus is a com m on foot deform ity seen after birth , occurrin g in as m any as 1 in 100 live birth s, an d is though t to result from intrauterine position ing. Th e deform ity con sists of an adducted forefoot, curved lateral border, an d a n eutral h eel, creatin g th e ch aracteristic “bean -sh ape’’ sole of the foot (Fig. 11.168). Adeep m edial crease is usually presen t. Most cases presen t durin g in fan cy as caregivers are often con cern ed about th e appearan ce of th e foot. After th e walking age, an in-toein g gait m ay be the presen ting com plain t. Physical exam in ation sh ould focus on determ in in g the flexibility of the deform ity. In addition, one can quan tify th e severity of th e deform ity by determ in in g th e h eel bisector lin e. Norm ally, a lin e drawn th rough th e lon g axis of th e h eel sh ould exit between th e secon d an d th ird toes. With in creasin g severity of th e con dition , th e h eel bisector lin e m oves laterally. Flexible deform ities can be treated with observation or stretchin g; 90% to 95% will spontan eously resolve regardless of treatm en t. Rigid deform ities sh ould un dergo serial m an ipulation an d castin g before 6 m on th s of age. Surgery is rarely required an d is in dicated on ly for ch ildren older than 3 years with a rigid deform ity that has n ot responded to serial castin g.

Figure 11.168 Metatarsus adductus in an infant. Note the con-

vex lateral border of the foot and the neutral hindfoot alignment. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Figure 11.169 Positional calcaneovalgus foot deformity. Note

that the dorsum of the foot is almost in contact with the anterior leg. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Calcaneovalgus Foot In a calcan eovalgus foot deform ity, th e h in dfoot extern ally rotates an d hyperdorsiflexes. In som e cases, th is causes th e dorsum of th e foot to be in con tact with th e an terior tibia (Fig. 11.169). The deform ity is prim arily positional and is thought to occur from intrauterine position ing. The estim ated incidence of calcaneovalgus foot deform ity is 0.4 to 1 in 1,000 live births, although som e believe that a m ild form can be see in up to 30% to 40% of newborn s. Although a calcaneovalgus foot is generally con sidered a benign condition, it is important to rule out other, m ore path ologic con dition s. Posterom edial bowin g of th e tibia is a condition in which the distal tibia is hypoplastic and bowed; th is can result in an apparen t calcan eovalgus deform ity. Posterom edial bowing can generally be distin guish ed from a true calcan eovalgus foot by determ ining th e location of th e apex of the deform ity: in posterom edial bowing, the apex is in the distal tibia, whereas in calcaneovalgus foot, the apex is in the joint (Fig. 11.170). Vertical talus can som etim es present with a sim ilar, dorsiflexed appearance of th e foot. In con trast to th e calcan eovalgus foot, a vertical talus h as far less flexibility.


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B Figure 11.170 (A) In posteromedial bowing, the apex of the deformity is in the distal tibia. (B) In

a calcaneovalgus foot, the apex of the deformity is in the joint. (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

For calcan eovalgus feet, gen tle stretch in g of th e foot in to plan tar flexion an d in version can be h elpful; h owever, m ost deform ities will resolve spon tan eously by 3 to 6 m on th s regardless of treatm ent. In patients with posterom edial bowing of the tibia, parents sh ould be counseled th at a leg length discrepancy (usually 3 –6 cm ) will m ost likely result.

Congenital Vertical Talus Con genital vertical talus (CVT) is a rare foot deform ity that is characterized by a hin dfoot that is in equinus and a forefoot that is dorsiflexed, resulting in a fixed m idfoot dislocation through the talonavicular joint. Un like calcaneovalgus feet, which are flexible, CVT is a rigid deform ity with a convex plantar surface that form s a rocker bottom deform ity (Fig. 11.171). Alth ough CVT can occur in isolation, m ore than 50% of cases are associated with a neurom uscular or gen etic disorder such as myelom en in gocele, arth rogryposis, an d trisom y 18. Ch ildren typically presen t durin g in fan cy with th e ch aracteristic foot appearan ce. The head of th e talus is usually palpable in th e m edial aspect of th e m idfoot. Th e an terior soft tissue structures are con tracted, in cludin g the toe exten sors, peron eals, an d an terior tibial ten don . Th e Ach illes ten don also is sh orten ed, wh ich fixes th e h in dfoot in an equin ovalgus position . True CVT sh ould be distin guish ed from an oblique talus, a condition in which the navicular is subluxated dorsally in relation to the talus but is still reducible. Plan tar flexion lateral radiograph s are useful to differen tiate th ese two clin ical en tities: if th e n avicular reduces on to th e talus wh en th e foot is position ed in m axim al plantar flexion , the diagnosis of an oblique vertical talus can be m ade (Fig. 11.172). If th e n avicular rem ain s dislocated in th is position , th e ch ild h as a vertical talus.

In itially, serial m an ipulation an d castin g is useful to stretch th e anterior skin as well as capsular and m usculoten din ous soft tissues. Historically, h owever, cast treatm en t alon e h as been in sufficien t to completely correct th e deform ity. Defin itive surgical correction typically con sists of a comprehensive open release, pin fixation of th e talonavicular join t, an d len gth en in g of th e an terior ten don s an d triceps surae. Surgery is usually perform ed between 6 an d 12 m on th s of age, an d results are better if surgery is perform ed before 2 years of age. Recently, Dobbs has described a n ew tech n ique con sistin g of serial m an ipulation an d cast im m obilization followed by percutaneous talonavicular pin fixation an d Ach illes ten otom y. Early results h ave

Figure 11.171 Clinical appearance of a foot with a congenital vertical talus. Note the rocker bottom deformity. (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, CA.)

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A

B Figure 11.172 Plantar flexion lateral views of an oblique (A) and vertical talus (B). In the oblique

talus, the navicular (unossified), and first metatarsal reduce on the talus. In a true congenital vertical talus, the talus remains plantar flexed in relation to the navicular (unossified) and metatarsal. (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, CA.)

dem on strated excellen t results in term s of clin ical appearan ce, deform ity correction , an d foot fun ction .

Flexible Flatfoot (Pes Planus) A flexible flatfoot is ch aracterized by a decrease in th e lon gitudin al arch of th e foot durin g stan ce alon g with valgus align m en t of th e h in dfoot. Th e con dition is con sidered flexible if subtalar m obility is preserved, as th is h elps distin guish it from oth er m ore path ologic processes (Fig. 11.173). Although a flexible flatfoot was th ought to be path ologic for m any years, at the present tim e, it is considered a variation of n orm al an d n ot a true path ologic en tity. All ch ildren

Figure 11.173 Hindfoot mobility can be assessed by cupping

the heel and shifting it from side to side (inverting and everting). (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

are flatfooted at birth as the arch does not norm ally develop un til after 2 years of age. Up to 25% of n orm al adults will retain som e degree of flat feet; th e vast m ajority does n ot cause any functional lim itations. Most ch ildren presen t because th eir caregivers are con cerned about the appearance of their feet. Pain is less often the cause for seeking care. The foot is ch aracterized by a collapsed arch with weight-bearing. When weight-bearing is discontinued, the arch reconstitutes itself. The hindfoot is usually in valgus but sh ould correct to varus when children stan d on th eir toes (Fig. 11.174). An kle ran ge of m otion and tightness of the h eel cord should be assessed by ch ecking dorsiflexion with the h indfoot in verted an d the knee both extended and flexed (Silfverskiö ld test). Radiograph s are rarely n ecessary to m ake th e diagn osis; h owever, lateral views of the foot will often dem onstrate a sag at the talon avicular join t an d an in crease in Meary an gle (th e an gle between the long axis of the talus and the long axis of the first m etatarsal). Most ch ildren are asymptom atic, but som e m ay h ave activity-related pain. If the child does not complain of pain , it is best to reassure th e caregivers, explain th e ben ign natural h istory of the con dition , an d avoid expensive orth otics. If symptom s are presen t an d th e h eel cords are tight, a stretchin g program is indicated. Arch supports can often be h elpful to reduce sym ptom s, but if m ore con trol of th e h in dfoot is desired, a larger orth osis such as a UCBL (nam ed for the University of Californ ia Biom echanics Laboratory, wh ere it was developed) or supram alleolar orth osis m ay be n ecessary. Surgery should be reserved for patients with continued pain in spite of m axim al conservative m anagem ent. Generally, it is best to avoid foot arth rodeses as th ese procedures can increase the risk of arth ritis in adjacent joints. The two m ost popular surgical procedures for correction are the m edial sliding calcaneal osteotomy


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B Figure 11.174 (A) Patient with flatfeet and hindfoot valgus. (B) When standing on the toes, the

hindfoot goes into varus, proving that the hindfoot is mobile, and the arch elevates, thus confirming a flexible flatfoot. (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

an d the lateral colum n len gthenin g. Th e form er procedure translates th e calcaneus m edially to reestablish the weightbearin g axis of th e h in dfoot. If th e forefoot rem ain s abducted after th e h in dfoot osteotomy, a closin g wedge osteotomy of th e m edial cun eiform an d an open in g wedge osteotom y of th e cuboid can restore forefoot an d m idfoot alignm ent. The lateral colum n len gthenin g takes advantage of th e win dlass m ech an ism to develop an arch an d correct the hindfoot. By placing a wedge of bone graft in the calcaneal neck, the previously sh ort lateral colum n of the foot becom es elon gated; th is h elps swin g th e foot in to a m ore an atom ic position.

Tarsal Coalition By definition, a tarsal coalition is an abn orm al fibrous, cartilaginous, or bony connection between two bon es of the hindfoot or m idfoot. Th e overall prevalence of tarsal coalitions has been reported to be 2% to 6% in the general population . Th e true prevalen ce, h owever, is difficult to ascertain since m any patien ts are asymptom atic and do not presen t for m edical care. Th e m ost com m on sites of coalition occur between the anterior process of the calcaneus an d the n avicular and between the talus and the calcaneus (through the m iddle facet of the talocalcaneal joint). Approxim ately 50% of patien ts h ave bilateral coalition s. Although m ost cases occur in isolation, tarsal coalitions have been associated with oth er disorder such as clubfoot, fibular hem im elia, and Apert syndrom e. Most patien ts presen t durin g adolescen ce wh en th e cartilaginous or fibrous connection s begin to ossify. Frequent an kle sprains and achin g pain over th e m edial aspect of the foot or the sinus tarsi are typical complaints. The m ost characteristic finding in a tarsal coalition is lim ited subtalar m otion and a valgus hindfoot. This lack of m obility is thought to be th e source of pain as th e stress of weigh t-bearin g gets

tran sferred to adjacen t join ts. Un like th e flexible flatfoot, patien ts with tarsal coalition s h ave a rigid flatfoot deform ity th at does n ot correct wh en ch ildren rise on th eir toes. Weigh t-bearing radiograph s are essential in the workup of a suspected coalition. Calcaneonavicular coalitions are best visualized on an oblique radiograph of th e foot. On th e lateral view, an elon gated an terior process of th e calcan eus, the so-called anteater nose sign m ay be seen (Fig. 11.175). Radiograph ic fin din gs of a talocalcan eal coalition in clude the “C-sign,’’ a line form ed from the outline of the talar dom e th at exten ds aroun d th e in ferior m argin of th e susten taculum tali, an d beakin g of th e dorsal talus (Fig. 11.176). Sin ce th ese fin din gs can be un reliable, CT scan s are often n ecessary to diagn ose talocalcan eal coalition s. Because of th e sign ifican t in ciden ce of m ultiple coalition s an d bilateral in volvem en t, th e presen ce of on e coalition sh ould prom pt furth er im agin g of both feet. Up to 75% of tarsal coalition s are asymptom atic; as a result, th e m ere presen ce of a coalition does n ot in dicate the n eed for treatm ent. For patients who are symptom atic, in itial m an agem en t sh ould con sist of activity m odification , NSAIDs, an d a trial of cast im m obilization an d/ or orth otics. In m any cases, th ese m easures will be sufficien t to decrease in flam m ation an d elim in ate pain . For th ose wh o rem ain symptom atic in spite of conservative treatm en t, surgical option s in clude resection of th e coalition or arth rodesis. Most calcan eon avicular coalition s respon d well to excision of th e coalition an d interposition of fat or th e exten sor digitorum brevis. Th e surgical treatm en t of talocalcan eal coalition s, h owever, is less clear. Th e classic teach ing is th at a resection should be perform ed if less than 50% of th e m iddle facet is involved and an arthrodesis sh ould be perform ed if th e coalition is m ore extensive. In reality, outcom es h ave been som ewh at un satisfactory followin g isolated resection , an d furth er studies are n eeded to determ in e wh ich patien ts are best treated by th is procedure. For patien ts with m oderate to severe valgus, results

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B

A Figure 11.175 (A) A calcaneonavicular coalition (arrow) is best seen on an oblique radiograph

of the foot. (B) Lateral radiograph demonstrating the anteater nose sign (arrows), indicating a calcaneonavicular coalition. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

after talocalcan eal coalition excision are improved if a con com itant calcaneal osteotomy is perform ed.

Clubfoot Clubfoot or talipes equin ovarus is a con gen ital foot deform ity th at is ch aracterized by th e CAVE m n em on ic (cavus, forefoot adductus, h in dfoot varus, an d equin us). Th e in ciden ce of th is con dition is approxim ately 1 to 2 per 1,000 birth s, an d 30% to 40% of cases occur bilaterally. Clubfeet can have a wide spectrum of presen tations from the m ild, postural form s to th e severe, rigid deform ities. Th e latter are usually associated with arth rogryposis, myelom en in gocele, Larsen syndrom e, or another underlying syndrom e. The etiology of talipes equinovarus rem ains unknown , but

Figure 11.176 A dorsal talar beak (white arrow) in a foot with a

talocalcaneal coalition. This represents a traction spur, not degenerative arthritis. The C-sign of Lafleur (black arrows) is a nonspecific indication of a talocalcaneal coalition. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

postulated th eories in clude an in utero arrest in th e fetal developm en t of th e foot, a retractile fibrotic respon se in the m edial ligam ents, and a prim ary gen etic defect. Th e path ophysiology of clubfeet in volves m ore th an just the osseous compon ents of the foot and should be considered a local dysplasia of all th e tissues of th e lower extrem ity from the knee down. The neck of the talus is shortened and deviated m edially an d plan tarward, causin g th e subjacen t calcaneus to rotate into varus. In turn, the calcan eus dislocates from the calcaneocuboid articulation, and as the forefoot m edially subluxes, the navicular becom es displaced dorsally an d m edially on to th e n eck of th e talus. Th is can be so extrem e th at th e n avicular will articulate with th e m edial m alleolus. It is im portan t to recogn ize th at n ot on ly is the talus deviated in an abnorm al direction but the sh ape of the talus itself is dysm orphic. Associated with these osseous deform ities are con tractures of th e capsules an d ligam en ts of th e an kle an d subtalar join ts. Th e ten don s of th e tibialis posterior, flexor h allucis longus, and flexor digitorum longus are contracted. These m uscles of the lower extrem ity are also sm aller and weaker than norm al. Histologic studies of m uscle tissue h ave dem on strated in creased in tracellular con nective tissue, m uscle atrophy, an d loss of myofibrils. Patien ts typically present soon after birth with the characteristic clinical appearance of the foot (Fig. 11.177). With improvem ents in prenatal ultrason ography, the diagnosis can often be m ade in utero; as a result, expectin g m others m ay occasionally present for counseling prior to the birth of th eir ch ild. Exam in ation of th e foot will reveal th e typical supin ation of the forefoot and equinovarus position ing of the hindfoot. Th e flexibility of the foot should be assessed by direct m anipulation . Radiographs are seldom n ecessary to m ake th e diagn osis but can be useful for surgical plann ing. In n orm al feet, the talus should line up with the first m etatarsal on both the AP and lateral views. With


Figure 11.177 Clubfoot deformity is associated with forefoot

supination, deep medial creases, and equinovarus of the hindfoot. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

increasing deform ity in clubfeet, the long axis of these two bon es progressively diverges. In addition , th e talocalcan eal an gle can be m easured on both views. On th e AP radiograph , th e lon g axis of th e talus an d th e calcan eus n orm ally diverge, creating a talocalcaneal angle between 20 an d 30 degrees. With increasing hindfoot varus seen in

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clubfeet, the talocalcaneal angle falls below 20 degrees. On the lateral view, the angle between the talus and the calcaneus should be between 35 and 50 degrees. In creased parallelism of th e two bon es, such th at th e lateral talocalcaneal angle decreases below 35 degrees, is indicative of a clubfoot (Fig. 11.178). Alth ough surgical release h as been h istorically favored as th e treatm en t for clubfeet, th e Pon seti m eth od of serial m an ipulation an d castin g h as gain ed widespread support an d h as revolution ized th e m an agem en t of talipes equin ovarus. Th is protocol aim s to first correct forefoot adduction , supin ation an d h in dfoot varus usin g stretching and a series of well-m olded long-leg plaster casts. Th ese casts are ch an ged every 1 to 2 weeks to effect gradual correction . Equinus should be addressed only after the other deform ities h ave been corrected; forced dorsiflexion in an in completely corrected foot can result in a m idfoot breach an d a rocker bottom deform ity. In th e vast m ajority of cases, an Achilles tenotomy is n ecessary to completely correct th e equin us con tracture. Several studies h ave sh own excellen t m id- an d lon g-term results an d decreased stiffn ess by using the Pon seti m eth od, com pared with feet that have been treated surgically. In certain cases, especially those involving arthrogryposis, myelom eningocele, or oth er syn drom es, surgery m ay still be n ecessary. Surgery is perform ed th rough a posterior (Cin cin n ati) in cision or double-in cision approach an d typically con sists of open reduction of th e talon avicular join t, rebalan cin g th e m edial an d lateral soft tissue structures, len gth en in g of th e

A

B Figure 11.178 (A) Simulated weight-bearing anteroposterior radiograph of a clubfoot. The talus

(small straight arrow) and calcaneus (large straight arrow) are parallel, rather than divergent. The cuboid ossification center (curved arrow) is medially aligned on the end of the calcaneus. (B) Maximum dorsiflexion lateral radiograph of a clubfoot. The talus and calcaneus are somewhat parallel to each other and plantar flexed in relation to the tibia. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

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Ach illes tendon, and pin fixation to h old the correction. Th e advan tage of open release is th e ability to correct severe deform ities; down sides in clude th e risk of stiffn ess an d overcorrection .

Osteochondroses O steoch on droses (local disorders of en ch on dral growth ) are a com m on cause of foot pain in growin g ch ildren . Kohler disease is osteonecrosis of the tarsal navicular. Typically, th is is seen in 4- to 6-year-old ch ildren wh o presen t with pain and swellin g aroun d th e arch of th e foot. Th e etiology of th e con dition is th ough t to be repetitive traum a. Th e radiograph will dem on strate in creased den sity an d sclerosis of th e navicular. O ccasion ally, the bone will appear flatten ed on th e lateral view. Treatm en t sh ould be conservative. During the symptom atic ph ase, short leg castin g followed by a lon gitudin al arch support is usually adequate to con trol symptom s. With in 1 year of on set, radiograph s usually dem on strate n orm alization of th e tarsal navicular. Avascular necrosis of the secon d m etatarsal head, known as Freiberg infraction, typically affects adolescents. Th e in creased in ciden ce in fem ales suggests th at th e frequen t discrepan cy in len gth between th e first an d secon d m etatarsal m ay be a factor. Again , repetitive m icrotraum a has been implicated as a causative factor. The radiograph s usually dem on strate flatten in g of th e in volved m etatarsal head. Conservative treatm ent is best, with short-term im m obilization an d appropriate orth otic use. Activity restriction particularly from jum pin g or con tact sports m ay be necessary. For those cases that do n ot respond to con servative m an agem en t, surgery m ay be in dicated. Tech n iques in clude excision of th e necrotic bon e with graftin g or simple sh ortenin g of the m etatarsal to relieve the weight-bearin g stress on the plantar surface. Sever disease is th e m ost com m on cause of h eel pain in children. Th e condition is an osteochondrosis of th e calcaneal apophysis. Typically, the patient is 5 to 10 years of age an d presen ts with h eel pain durin g or after activity. Physical findin gs generally consist of tendern ess over the tuberosity of the os calcis; radiographs usually dem onstrate fragm entation ch anges of the apophysis that can be m isin terpreted as path ologic. Th ese latter ch an ges reflect the norm al irregular ossification of this secondary ossification center. Treatm ent consists of activity m odification, judicious use of NSAIDs, h eel cups, an d h eel cord stretch in g. In jection s with lidocain e or cortisone are generally avoided.

Juvenile Hallux Valgus Sim ilar to th e adult bun ion deform ity, juven ile h allux valgus is ch aracterized by lateral deviation of th e great toe an d prom in en ce of th e first m etatarsal h ead. Both m etatarsus prim us varus an d pes plan us can be associated with h allux

valgus. A strong fam ily history of the disorder is usually presen t, with m ost patien ts in h eritin g th e con dition from th eir m oth er. Most adolescen ts with h allux valgus are asymptom atic but m ay presen t because of con cern s about th e cosm etic appearan ce of th eir feet. Wh en pain is presen t, it is gen erally located over the prom in ence of the m etatarsal head an d is exacerbated by wearin g tigh t-fittin g sh oes. Weigh t-bearin g radiograph s are essen tial to accurately quan tify th e severity of the deform ity. As in adults, the h allux valgus angle, th e in term etatarsal an gle, an d th e distal m etatarsal articular angle can all be m easured on th e AP radiograph; th ese m easures help identify the causes of the deform ity and aid in planning surgical correction. Treatm en t of th e adolescen t bun ion sh ould be largely con servative. Sh oe m odification s, toe spacers, an d splin ts can all be useful to provide sym ptom atic relief. Most auth ors recom m en d waitin g un til skeletal m aturity before pursuin g surgical treatm en t for adolescen t bun ion s. In younger patient, recurrence following surgical correction is com m on, and m any series report only 50% to 60% good results. Depen din g on th e preoperative radiograph ic assessm en t, surgical treatm ent after skeletal m aturity generally consists of a double m etatarsal osteotomy or proxim al crescen tic osteotom y of th e first m etatarsal alon g with distal soft tissue realign m en t.

Other Toe Deformities Con genital deform ities of the toes are relatively com m on. Syn dactyly can occur an d, as with fin gers, can be partial or com plete. Radiograph s are useful to distin guish sim ple (soft tissue involvem ent on ly) from complex (soft tissue an d bone involvem ent). Unlike in the hand, separation is n ot typically n ecessary, sin ce syn dactyly of toes does not cause a functional deficit. Congenital curly toe is another com m on finding. Frequen tly, this condition is bilateral and usually affects th e secon d or th ird toe. Curly toe h as a h igh fam ilial in ciden ce an d causes a great deal of paren tal con cern. Un fortun ately, it does n ot correct spon taneously and ten ds to worsen with growth . In itially, tapin g an d stretch ing can be used but when symptom s worsen, flexor tendon recon struction m ay be n ecessary.

SHOULDER AND ELBOW Sprengel Deformity Spren gel deform ity is ch aracterized by a failure of th e scapula to descen d from its norm al em bryologic level at C4 to the thoracic region. Typically, the scapula develops adjacent to the cervical som ites and completes its descent to th e th oracic region by 3 m on th s of fetal life. In Spren gel deform ity, th e scapula is retain ed in its cervical position by a fibrous, cartilagin ous, or osteocartilagin ous bar. The


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in g con gen ital scoliosis, Klippel–Feil syn drom e, con gen ital m uscular torticollis, an d ren al an d facial deform ities. Th e treatm en t of Spren gel deform ity varies with th e severity of th e condition . For the vast m ajority of patients in wh om th e cosm etic deform ity is m ild an d m otion is adequate, on ly observation is required. For m ore severe cases, surgical correction usually consists of th e Woodward procedure in wh ich th e om overtebral bon e is resected an d the trapezii, rhom boids, an d levator m usculature are released from th eir spin al attach m en ts an d advan ced distally to lower th e scapula. Resection of th e superior border of th e scapula im proves the cosm etic outcom es. In children older than 7 years, th e m idportion of th e clavicle should be resected an d m orselized to m inim ize the risk of traction palsy to th e brach ial plexus as th e scapula is advan ced distally.

Congenital Pseudarthrosis of Clavicle

Figure 11.179 Three-year-old child with right-sided Sprengel deformity in addition to Klippel–Feil syndrome. Note the elevated and hypoplastic right scapula. (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, CA.)

con dition is m ore com m on in fem ales than m ales and affects the left shoulder m ore often than th e right. Th e clin ical features of Spren gel deform ity in clude a hypoplastic, h igh -ridin g scapula with a variable degree of gen eralized m uscular atrophy about th e en tire sh oulder girdle (Fig. 11.179). In approxim ately on e-th ird of cases, an om overtebral bon e can be iden tified. Som e patien ts will dem on strate decreased ran ge of m otion in th e sh oulder, particularly in abduction ; h owever, in m any cases, th e com plain ts are prim arily cosm etic in n ature. It is essen tial for the treating physician to recognize that Sprengel deform ity can be associated with other congenital anom alies, includ-

Figure 11.180 Pseudarthrosis of

the right clavicle in an 8-day-old male infant. (Reproduced with permission from Skaggs DL, Flynn JM: Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Congenital pseudarthrosis of the clavicle is a rare con dition in which the m edial and lateral ossification centers of th e clavicle fail to un ite (Fig. 11.180). Typically, in fan ts with th is defect presen t with a palpable m ass in th e cen ter of th e clavicle. Th e con dition alm ost always occurs on th e righ t side, un less dextrocardia is presen t. Th e radiograph ic appearance is often confused with a clavicle fracture, but th e con dition is n ot pain ful. Th e diagn osis is con firm ed by lack of callus on subsequent radiographs. The natural history of this condition is benign as virtually n o fun ctional deficits h ave been reported. As a result, m ost ch ildren do n ot require treatm en t. Open excision of th e pseudarth rosis site, bon e graftin g, and fixation are generally successful for those ch ildren who report discom fort or are concerned about th e cosm etic appearan ce of the bump.

Brachial Plexus Palsy Th e in ciden ce of brach ial plexus palsy h as been estim ated between 0.13 an d 3.6 cases per 1,000 live birth s. Risk factors

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Figure 11.181 This patient with

Erb palsy has the left arm in the characteristic “waiter’s tip” position. (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

in clude m atern al diabetes, large birth weigh t, prolon ged labor, forceps delivery, an d sh oulder dystocia. The m ost com m on type of brachial plexus palsy affects the upper trunk (C5 an d C6) and is known as Erb palsy. Th is palsy h as th e ch aracteristic waiter’s tip appearan ce due to sh oulder in tern al rotation , elbow exten sion , forearm pronation, and wrist flexion (Fig. 11.181). With complete plexus in volvem en t, th e n eon ate’s lim b is often totally flaccid and m ay be associated with Horn er syn drom e (ptosis, m iosis, an d en oph th alm os) of th e ipsilateral eye wh en th e sympathetic chain is affected. The m an agem ent of brach ial plexus palsies rem ain s con troversial. Typically as few as 1 out of 10 in fan ts with plexus palsies at birth will require surgical in terven tion , so th e goal of in itial m an agem en t is to m ain tain passive ran ge of m otion wh ile m otor fun ction is recoverin g. Historically, brach ial plexus exploration with or with out n erve graftin g has been recom m en ded if there is n o recovery in biceps function between 3 and 6 m onths. Arecent study, however, has suggested that there are patien ts with no biceps recovery by 3 m onths who can even tually achieve adequate biceps an d sh oulder fun ction with out surgery. Ch ildren with persisten t late deform ity are best treated by various techn iques to improve sh oulder rotation sin ce th e fixed in tern al rotation position m arkedly in h ibits h an d fun ction . Release of th e pectoralis m ajor an d subscapularis m uscles can often improve extern al rotation . Th e L’Episcopo procedure, which is a tran sfer of th e teres m ajor an d latissim us dorsi to a lateral position , produces a sim ilar effect. Som e auth ors prefer extern al rotation osteotom y of th e h um erus because of m ore reliable outcom es. Before executin g any of th ese

procedures, care m ust be taken to en sure th at th e h um eral h ead is well located in th e glen oid because a n um ber of children will develop posterior shoulder dislocation s from prolon ged in tern al rotation con tracture. Alth ough m ost of th e late sequelae are th e result of con tracture, a sm all n um ber of ch ildren are afflicted by a pure flaccid paralysis. In th is situation , th e on ly option s are sh oulder arth rodesis and elbow flexorplasty.

Congenital Dislocation of Radial Head Perhaps the m ajor sign ificance of this rare condition is in the differen tiation between it and an acquired dislocation of th e radial h ead, wh ich can occur after an un recogn ized Mon teggia fracture dislocation . The congenitally dislocated radial h ead is m ore often con vex or flatten ed as opposed to th e n orm al radial h ead, wh ich is con cave with a cen tral depression (Fig. 11.182). The child with a congenital dislocation of th e radial h ead often presen ts after m in or traum a when the parents n otice a prom inent “bump’’ on the lateral side of the elbow. Som e restriction in pronation or supin ation m ay be seen , but th is con dition rarely causes any functional lim itations. Treatm en t of con gen ital dislocation of th e radial h ead usually con sists of ben ign n eglect. Attem pts at surgical reduction are fraugh t with com plication s. Th e vast m ajority redislocate, frequen tly leavin g th e elbow stiffer th an it oth erwise would h ave been . After physeal closure, on e can con sider excision of the radial head in cases of severe cosm etic deform ity.


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sifican s develop, furth er loss of function will occur. Occasion ally, an osteotomy can be useful to place the han d in a m ore functional position. For example, a forearm fixed in supin ation can be m ade m ore functional by being rotated in to sligh t pron ation , wh ich im proves writin g an d keyboard use.

HAND AND WRIST Madelung Deformity

Figure 11.182 Lateral radiograph of a congenital posterolateral dislocation of the radial head. Note that the radial head appears small and dome-shaped. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Congenital Radioulnar Synostosis Th is abn orm al fusion between th e radius an d uln a m ay occur proxim ally, distally, or in both locations (Fig. 11.183). It is often bilateral and is inh erited as an autosom al dom inant con dition. Typically, it is iden tified in the older ch ild when som e m ild function al impairm ent, especially in throwing sports, is recogn ized. Most children adapt well to th e lim ited m otion in the forearm by compen sating at the shoulder an d th e wrist. As a result, surgery is usually n ot n ecessary. Procedures design ed to resect th e syn ostosis h ave notoriously poor results. Usually no in crease in pronation or supin ation can be ach ieved; in fact, sh ould myositis os-

True Madelung deform ity is a con genital anom aly that results from arrest of th e ulnar and volar portions of the distal radial growth plate (Fig. 11.184). As a result, a un ique carpal deform ity results, referred to as a trian gulation defect of th e distal radius. Th e distal radius an d uln a appear V-sh aped, with th e carpus h avin g m igrated som ewh at cen trally. Th e con dition is tran sm itted as an autosom al dom in an t trait, is m ore com m on in fem ales, and frequently is bilateral. Wh en th e an om aly is prim arily cosm etic, little or n o treatm ent is required. In m ore severe cases, surgical options include epiphysiodesis of the rem aining distal radial physis to m in im ize progression , osteotom y of th e distal radius to correct deform ity, resection of th e distal uln a, an d ultim ately wrist fusion . An acquired type of Madelun g deform ity can be seen following dam age to the distal radial physis from osteomyelitis or traum a.

Syndactyly Webbing or fusion of two or m ore fin gers is th e m ost com m on congen ital anom aly of the hand. It results from a failure of differen tiation between adjacen t fin gers. Th e m ost com m on con n ection occurs between th e lon g an d rin g finger. Males are affected twice as often as fem ales, with a fam ilial in ciden ce of 25%. It is importan t to determ in e th e exten t of soft tissue an d bony in volvem en t. Syn dactyly th at in volves on ly skin an d soft tissue is referred to as simple syndactyly, whereas th ose with bony fusions are referred to as complex syndactyly (Fig. 11.185). As with radial deficien cy syn drom es, it is importan t to be sure th at th ese are isolated phenom en a. Num erous syndrom es and anom alies h ave been associated with syndactyly, including Apert syn drom e an d Polan d syndrom e. Surgical separation typically im proves fin ger an d h an d function . If left uncorrected, syn dactyly will cause the longer of th e two fingers to deviate; th erefore, surgical interven tion is gen erally recom m en ded with in th e first year of life.

Polydactyly Figure 11.183 Lateral radiograph of the elbow showing a proxi-

mal congenital radioulnar synostosis. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Extra digits are usually obvious at birth (Fig. 11.186). Th e supern um erary digit m ay be postaxial (on the ulnar side of th e h an d) or preaxial (on th e radial side of th e h an d).

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A

B Figure 11.184 (A) Anteroposterior view of the wrist demonstrating the characteristic Madelung deformity from incompetence of the ulnar and volar portions of the distal radial growth plate. (B) Postoperative radiograph after corrective osteotomy of the distal radius and ulna. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Again , it is important to con firm wh eth er or not the extra digit is soft tissue or bony, an d if bony, wh eth er it con tain s on ly ph alan ges or its own m etacarpal. Polydactyly is 10 tim es m ore com m on in the African Am erican population than in Caucasians and m ost com m on ly postaxial. Sm all fin ger duplication s are rarely associated with other anom alies an d are inh erited as an autosom al dom in an t trait. Duplicated th um bs, h owever, can be associated with oth er abn orm alities. Soft tissue

polydactylies an d “n ubbin s’’ can be easily ligated in th e n ewborn n ursery. Rem oval of bony duplication s and extra thum bs are som ewhat m ore complex procedures and sh ould be perform ed in the operating room .

Congenital Trigger Thumb Con genital trigger thum b is on e of the m ore com m on han d problem s in ch ildren . Typically, th e ch ild presen ts with

A

B Figure 11.185 (A and B) A 1 year-old child with complete simple third web-space syndactyly. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)


A

351

B Figure 11.186 (A) Complete postaxial polydactyly with phalangeal duplication and a conjoined metacarpal. B: Radiographs of the same patient. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

“locking’’of the interph alangeal join t of the thum b. Usually the deform ity is fixed and th e “clickin g,’’ typical in adults, is rarely seen in ch ildren. Depending on the age of presentation , m any will resolve spon tan eously. As a result, it is best to sim ply observe ch ildren th rough out th e first year of life. Those who continue to have issues into ch ildhood are best treated by ten olysis th rough th e A1 pulley.

MISCELLANEOUS CONDITIONS

Etiology Many differen t conditions can cause a leg length inequality. Congen ital causes such as PFFD and fibular hem im elia h ave been previously discussed. DDH with a high dislocation can sim ilarly cause a differen ce in lim b len gth s. Acquired con dition s such as juven ile rh eum atoid disease, dam age to th e physis followin g traum a or in fection s, an d obscure etiologies such as radiation an d burn s are all capable of producin g un equal lim b len gth s. Even n eurom uscular con dition s such as CP can produce a lim b len gth discrepan cy.

Limb Length Discrepancy Frequen tly, orth opaedic surgeon s are asked to evaluate th e ch ild with a lim b length discrepancy. There are num erous con genital an d acquired causes for this, and the treatm ent will n eed to be in dividualized on th e basis of th e cause an d the extent of the inequality. Modest lim b length discrepan cies are relatively com m on: one study of healthy m ilitary recruits dem on strated a 32% in ciden ce of leg len gth discrepancies between 0.5 an d 1.5 cm . Although there are som e contradictory reports in the literature, th e gen eral con sensus is that sm all discrepancies (< 2 cm ) do not increase the risk of future back or hip problem s. These m inim al discrepan cies can be well tolerated by the individual an d require essentially no treatm en t. On the other hand, exten sive differen ces m ay require sign ifican t procedures to overcom e th e oth erwise-an ticipated disability.

Evaluation Th e h istory of a ch ild with lim b len gth discrepan cy sh ould be screen ed for both con gen ital an d acquired causes. Fam ily history m ay be helpful for identifying inherited disorders. Birth h istory an d th e tim e th at th e discrepan cy was first noted are also important: discrepancies present at birth are alm ost certainly due to congenital hypoplasia or DDH. On physical exam ination , absolute leg length inequality can be determ in ed by comparin g th e len gth of th e two legs from th e anterior superior iliac spine to the m edial m alleolus. Th is tech n ique does n ot accoun t for an gular ch an ges or for deform ities of th e foot an d an kle. Apparen t discrepancy is m easured from the um bilicus to the m edial m alleolus; th is is also a less useful m easure sin ce it can be in fluen ced by h ip adduction con tractures, pelvic obliquity, an d

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Ruler

X-ray film

Figure 11.187 Limb lengths can be accurately assessed by placing your fingers on the iliac crests and using blocks to level the pelvis. (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

position in g. Th e m ost accurate an d efficien t way to clin ically evaluate a leg length discrepancy is to have the child stand on m easured blocks until the pelvis is level (as judged by a finger placed on each iliac crest) (Fig. 11.187). This tech n ique is th e m ost fun ction al m easure as it accoun ts for both an gular m alalign m en t an d foot deform ity. It is also importan t to observe th e ch ild walkin g, to look for compen satory m ovem ents and to determ in e the functional effect of th e discrepan cy. In m ost cases, ch ildren vault over th e lon g leg, walk with th e kn ee of th e lon g leg flexed, an d/ or toe-walk on th e sh ort side. Accurate radiographs, including scan ogram s and teleoroen tgen ogram s, are essen tial in th e evaluation of lim b len gth discrepan cies. A teleoroen tgen ogram is a sin gle AP radiograph of both lower extrem ities (including hips, knees, and an kles) taken on top of a ruler. An advantage of this film is visualization of th e entire lower extrem ity and the sin gle exposure (since children often have difficulty staying still) (Fig. 11.188). Am ajor disadvantage, especially in larger ch ildren , is m agn ification error because th e sam e x-ray beam strikes th e h ips, kn ees, an d an kles at differen t an gles. Scan ogram s m in im ize th is error by m ovin g a sm aller cassette ben eath th e patient and obtain ing m ultiple orth ogon al exposures of th e h ip, kn ees, an d an kles (Fig. 11.189). Alth ough m ore accurate, this tech nique requires th at th e patien t lay still between exposures (Fig. 11.190). In addition , scanogram s do not allow visualization of th e fem oral an d tibial diaphyses n or do th ey accoun t for foot deform ity in the overall m easurem ent of leg len gth discrepan cy. Both teleoroen tgen ogram s an d scan ogram s can give false readings in children with h ip or knee contractures or rotation al m alalign m en ts. In th ese cases, CT scan ogram s are a m ore accurate option .

Table

Figure 11.188 The teleoroentgenogram takes a single exposure of the hips to ankles and is subject to the errors of magnification. However, it is probably the best technique for children who cannot reliably comply with instructions to remain still for multiple exposures. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Skeletal growth typically en ds aroun d 14 years of age in girls and 16 years of age in boys. Although chronologic age provides som e in form ation about a ch ild’s skeletal m aturity, th ere can be sign ifican t variability from ch ild to ch ild, depen din g on th e on set of puberty. A m ore accurate way to estim ate skeletal m aturity is to determ in e th e ch ild’s bon e age. Th is is done by obtaining a posteroan terior radiograph of th e h an d an d wrist an d com parin g th e fin din gs to a

Ruler

X-ray film

Table

Figure 11.189 The scanogram technique avoids magnification

error by exposing each joint individually. The child must remain still for each exposure. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)


Figure 11.190 Scanogram allows the images of the three joints

to be captured on a radiograph of convenient size by moving the radiograph beneath the patient between exposures. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

referen ce atlas. Th ese bon e age m easurem en ts are usually accurate to within 6 m onths but are notoriously inaccurate in children younger than 6 years.

Management It is importan t to rem em ber th at th e focus of treatm en t is not the presentin g leg length discrepancy but rath er th e predicted leg len gth discrepan cy at skeletal m aturity. As a result, proper m an agem en t of a growin g ch ild with a lim b len gth discrepan cy depen ds on accurate prediction of th e discrepan cy at skeletal m aturity. There are four com m only used tech n iques for predictin g lim b len gth discrepan cy, each with a differen t level of accuracy an d complexity. Th ese in clude the arith m etic m eth od, growth-rem ainin g m ethod, m ultiplier m ethod, an d the straight-line m ethod. Regardless of the techn ique, the poten tial accuracy of these predictive m ethods is improved by longitudinal data. Therefore, repeated leg len gth m easurem en ts at 6- to 12-m on th in tervals provide m ore inform ation from which to base these future prediction s. Th e arith m etic m eth od of Men elaus, also kn own as the rule-of-thum b m ethod, is the m ost straightforward m ethod for predicting leg length inequality. The technique

353

is based on th e followin g assumption s regardin g growth : (1) girls stop growin g at age 14, (2) boys stop growin g at age 16, (3) th e distal fem oral physis grows 10 m m a year, an d (4) th e proxim al tibial physis adds 6 m m of growth a year. By comparin g th e patien t’s curren t ch ron ologic age to these assumption s, on e can estim ate the am ount of growth rem ain in g. Th is tech n ique is useful on ly for th e few years precedin g skeletal m aturity an d, alth ough sim ple, is con sidered th e m ost in accurate. Th e growth -rem ain in g m eth od is based on growth tables publish ed by Green an d An derson (Fig. 11.191). Growth percen tiles can be calculated by comparing a child’s leg len gth s an d age to th e tables. Oth er graph s allow th e prediction of growth rem ain in g an d th e effects of epiphysiodesis. Alth ough it is th e lon gest-stan din g tech n ique for predictin g leg len gth discrepan cy, m any fin d th e m eth od cum bersom e as it requires referral to two separate sets of graphs. The m ultiplier m ethod is based on the sam e Green an d An derson data but allows prediction of leg len gth discrepancy with out the need for bone age or graph ing. Based on th e ch ild’s gen der an d ch ron ologic age, th e fin al leg len gth discrepan cy can be determ in ed by m ultiplyin g th e existin g discrepan cy by a factor determ in ed from a referen ce table. Alth ough accurate for con gen ital discrepan cies, som e auth ors believe th at th e m ultiplier m eth od un derestim ates the importance of skeletal age in predictin g final discrepan cies. Th e Moseley straigh t-lin e m eth od is con sidered th e m ost accurate tech n ique for predictin g leg len gth differen ces but requires m ultiple m easurem en ts an d graph ic in terpretation (Fig. 11.192). Th e straigh t-lin e m eth od is also based on th e Green an d An derson growth data: bon e age an d leg len gth s are used to determ in e growth percen tile, an d th e growth of both lim bs are expressed graph ically by two straigh t lin es. By com parin g th e differen ce in th e slopes of both lin es, on e can predict th e leg len gth discrepan cy at m aturity. Treatm ent option s depend on the m agnitude of th e predicted leg len gth discrepan cy (Table 11.5). Sin ce leg len gth discrepan cies less th an 2 cm are well tolerated, treatm en t is usually n ot n ecessary. For n oticeable differen ces, a sh oe lift or orth otic can be h elpful. For predicted discrepan cies between 2 to 6 cm , treatm en t option s in clude larger sh oe lifts, acute sh orten in g, or epiphysiodesis. Gen erally, lifts larger

TABLE 11.5

GUIDELINES FOR THE TREATMENT OF LEG LENGTH DISCREPANCY Discrepancy

Treatment

< 2 cm 2–6 cm 6–20 cm > 20 cm

No treatment or shoe lift Shoe lift, acute shortening, or epiphysiodesis Lengthening Amputation and prosthetic fitting

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100 +2 S.D. +1 S.D.

90

Mean −1 S.D.

Boys 80

−2 S.D.

Leg length (cm)

70 60 50 40 30 20 10 0 1

2

3

4

5

6

7

A

8 9 10 11 Skeletal age (yr)

12

13

14

15

16

17

18

100 90

+2 S.D. +1 S.D.

Leg length (cm)

Girls 80

Mean −1 S.D.

70

−2 S.D.

60 50 40 30

Figure 11.191 (A) Graph showing

20 10 0 1

B

2

3

4

5

6

7

8

9

10

11

12

Skeletal age (yr)

than 5 cm are poorly tolerated because of ankle instability an d frequen t sprain s, as well as th e h eavin ess of lifts of such size. Acute fem oral shorten in g is in dicated for discrepan cies less th an 5 to 6 cm in wh ich th ere is in sufficien t growth rem ain in g for an epiphysiodesis to work. Surgery can be perform ed using an in tram edullary nail or plate for fixation . A m ajor disadvan tage of th is tech n ique is quadriceps weakness due to the disrupted len gth –ten sion relation sh ip of th e m uscle. Th e best treatm en t option for a m oderate leg len gth

13

14

15

16

17

18

total leg length versus skeletal age for boys allows a specific boy to be related to the population by plotting his leg length as a function of his skeletal age. (B) Equivalent plot for girls. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

discrepan cy in a ch ild with sufficien t growth rem ain in g is a well-tim ed epiphysiodesis (Fig. 11.193). On the basis of th e m eth od of prediction , on e can estim ate wh en to close th e growth in th e distal fem oral physis an d/ or th e proxim al tibial physis of th e lon ger leg so that th e leg lengths rough ly equalize by th e tim e th e ch ild fin ish es growin g. In gen eral, it is better to aim for sligh t un dercorrection sin ce sm all discrepan cies are well tolerated and fam ilies are often un h appy if th e lon g leg is sh orten ed too m uch . Surgery is

355

Leg length (cm)


Skeletal age—girls Reference slopes

ia Tib

Leg length (cm)

ur m Fe Both

ng o L

g le

Straight line graph for leg-length discrepancy Skeletal age—boys

Figure 11.192 The straight-line graph com-

prises three parts: the leg length area with the predefined line for the growth of the long leg, the areas of sloping lines for plotting skeletal ages, and reference slopes to predict growth following epiphysiodesis. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Figure 11.193 Example of a percutaneous epiphysiodesis per-

formed on the proximal tibial physis. The physis is ablated with a drill followed by a curette. (Reproduced with permission from Morrissey RT, Weinstein SL. Atlas of Pediatric Orthopaedic Surgery. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

typically perform ed in a percutan eous fashion using a drill and curette to scrape out the physis. Although th e surgery is tech n ically straigh tforward, it is importan t to double-ch eck growth calculation s as th e operation is perm an en t. Larger predicted leg length discrepancies (6 –20 cm ) m ay be am en able to lim b len gth en in g. Several tech n iques exist, but m ost in volve a m in im ally in vasive osteotom y followed by gradual increm ental distraction usin g an extern al fixator (Fig. 11.194). Typically, the bone is lengthened 1 m m a day. After th e goal len gth is ach ieved, th e fixator is m ain tain ed in place until the regenerated bone con solidates. Controversy exists over wh at is the m axim um achievable lengthen in g, but m ost auth ors agree th at it is th e con dition of th e soft tissues, n ot th e bon e, that determ in es th e endpoint of treatm ent. Although lim b length ening can produce som e impressive results, it is vital that fam ilies and physicians un derstan d th at th e process is lon g an d arduous, often taking a physical and psychological toll on both the patient and the caregiver. Complications should be expected an d include joint contracture, joint subluxation or dislocation,

356


Figure 11.194 Example of a circular external fixator (tibia) and

a monorail fixator (femur) used to achieve gradual lengthening of both bones. Note the regenerate bone at the site of both lengthenings. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

m uscle weakn ess, n eurovascular in jury, refracture th rough regen erate bon e, an d pin -site in fection . For even larger predicted discrepan cies (> 15 –20 cm ), amputation an d prosthetic fitting is usually th e best option. Although difficult to accept, amputation offers an easier treatm en t course an d superior lon g-term fun ction compared with a h eroic len gth en in g.

The Limping Child A limp is a com m on reason for a child to present to an orthopaedic surgeon . Although this is a relatively com m on problem , evaluation can be difficult. Multiple etiologies, the child’s difficulty in localizing pain, an d a vague history m ake it essen tial th at th e physician h ave a system atic approach to th is problem .

History and Physical Examination Although th e differen tial diagnosis for a limp m ay be long, a careful history will narrow the possible diagnoses and h elp focus diagn ostic testin g. Th e age of th e ch ild provides the first clue to the diagn osis as certain conditions are far m ore prevalent in certain age groups (Table 11.6). Ahistory of traum a or recen t illn ess is im portan t to elicit as it suggests fracture or infection as a possible etiology. Likewise, a history of failin g to m eet developm en tal m ileston es or, worse, a deterioration in m otor ability suggests a m etabolic or n eurom uscular cause. Paren ts, an d ch ildren if possible, sh ould be asked about th e ch aracter of th e limp, th e presen ce or absen ce of pain, and th e tim in g and duration of symptom s. A pain ful limp is m ore likely due to traum a, in fection , or m alignancy, whereas a painless limp is m ore often caused by a m etabolic, congenital, or neurom uscular abnorm ality. In addition , th e ch aracter of th e pain itself can provide useful inform ation. Pain with acute onset is probably caused by fracture or infection ; pain that gradually worsens over tim e is m ore likely caused by m echanical, inflam m atory, or n eoplastic con dition s. Morn in g pain is suggestive of an inflam m atory con dition such as JRA. Pain after activities is associated with m echanical an d overuse injuries. Night pain is ch aracteristic of m align an t con dition s. Th e m ost importan t step in th e physical exam in ation of a ch ild with a lim p is observin g th e ch ild walk. Ch ildren sh ould be dressed in a gown or gym sh orts so th at th e lower extrem ities can be adequately visualized. Because of the sm all size of m ost exam ining room s, it is usually better to h ave th e patien t walk in a n earby h allway. Several “laps’’ m ay be needed so th at each aspect of the gait (i.e., h ips, knees, ankles) can be evaluated sequen tially. Norm al gait occurs in two ph ases—stan ce and swin g. The stance ph ase begin s with in itial con tact for a given lim b an d term inates with toe-off of th at extrem ity. Stance accounts for approxim ately 60% of the gait cycle, norm ally leaving 40% of th e cycle for swin g. Th e swin g ph ase begin s wh en th e foot leaves th e ground and ends at initial contact of the con tralateral lim b. Most children learn to walk between 12 an d 18 m onths of age. Early gait is characterized by short stride len gth s, fast cadence, an d a widen ed stan ce. Adultlike gait develops by the age of 7. Th ere are several specific types of limps th at deserve m en tion. An antalgic gait is caused by pain in the affected extrem ity. Th is leads to a sh orten ed stan ce ph ase on th e pain ful side an d a sh orten ed stride len gth on th e con tralateral side (as ch ildren tran sfer th eir weigh t back to th e good leg as quickly as possible). An talgic gaits are seen in children with fracture, in fection , or foreign bodies in th e foot. A Trendelenburg gait results from weakness of the hip abductors. Durin g stan ce on th e affected side, th e con tralateral pelvis drops because of th e m uscle’s in ability to stabilize th e pelvis. To m ain tain balan ce, ch ildren will often lean th eir torsos over th e affected side. Com m on causes of th is type of gait in clude developm en tal h ip dysplasia, Legg-CalvéPerthes disease and slipped capital fem oral epiphysis. A


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TABLE 11.6

DIFFERENTIAL DIAGNOSIS OF A LIMPING CHILD < 4 Years of Age

4–10 Years of Age

> 10 Years of Age

Fracture Osteomyelitis, septic arthritis, diskitis Juvenile rheumatoid arthritis Lyme disease Discoid meniscus Foreign body in the foot Tumor DDH Cerebral palsy Leg length discrepancy

Fracture Osteomyelitis, septic arthritis, diskitis Juvenile rheumatoid arthritis Lyme disease Discoid meniscus Transient synovitis Tumor DDH Cerebral palsy Leg length discrepancy Osteochondritis dissecans Legg–Calve–Perthes disease ´ Muscular dystrophy Slipped capital femoral epiphysis Accessory tarsal navicular Sever apophysitis

Fracture Osteomyelitis, septic arthritis, diskitis Apophysitis (e.g., Osgood–Schlatter disease) Tumor Cerebral palsy Osteochondritis dissecans Legg–Calve–Perthes disease ´ Muscular dystrophy Slipped capital femoral epiphysis Tarsal coalition Accessory tarsal navicular

DDH, developmental dysplasia of the hip. (Adapted from Flynn JM, Widmann RF. The limping child: evaluation and diagnosis. J Am Acad Orthop. 2001;9(2): 89–98.)

ch ild with a short leg limp m ay m anifest one of m any compensatory m ech anism s to account for the leg length inequality. Som e children will circum duct the long leg to improve foot clearance; oth ers will vault with the short leg or toe-walk to ach ieve fun ction al equalization of th eir leg lengths. In addition to observin g th e ch ild’s limp, th e exam in er sh ould carefully range every m ajor joint and palpate th e lower extrem ities to determ in e a poin t of m axim um tendern ess. By localizin g th e source of th e sym ptom s, on e can narrow the differential diagnosis and drastically reduce th e need for excess im agin g. AGowers test should be perform ed on alm ost every ch ild to m in im ize th e ch an ce of m issin g a m uscular dystrophy.

Diagnostic Studies Th e ch oice of diagn ostic studies sh ould be guided by in form ation garnered from the history and physical exam ination. Norm ally, h igh -quality plain radiographs are the first im agin g m odality th at sh ould be obtain ed. For ch ildren wh o can localize th eir sym ptom s, orth ogon al views sh ould be taken of the region including the join t above an d the joint below the point of m axim al tenderness. Oblique views, especially in the foot and ankle, are helpful to iden tify subtle fracture lin es or m inor physeal widen ing. Bone scans are an excellent test for evaluatin g a lim pin g child in wh om the history and physical exam in ation are unable to localize th e an atom ic region th at is affected. Sen sitive, but n ot specific, bon e scan s can iden tify fracture, in fection , or m align an cy. Ultrason ography is th e diagn ostic study of ch oice for the evaluation of hip joint effusions. Ultrason ography is n on in vasive, does n ot require sedation , an d can be

used to guide aspiration . MRI, wh ile n ot appropriate as a first-lin e test, is extrem ely useful in th e workup of suspected stress fractures an d m align ancies. Laboratory testing is indicated for children with constitution al symptom s including fever, m alaise, or weight loss. Appropriate tests in clude a complete blood cell coun t with differential coun t, an ESR, and a CRP. White blood cell counts m ay be elevated only in 20% to 30% of children with osteom yelitis, but a left sh ift in th e differen tial is m ore sen sitive for in fection . Extrem ely elevated coun ts can be seen in both JRA an d leukem ia. ESR an d CRP are n on specific in flam m atory m arkers th at are excellen t screen in g tests for in fection an d autoim m un e disease. Th e ESR is som ewh at less useful th an CRP because it is slow to rise in th e early ph ase of an acute process an d rem ain s elevated for up to 3 weeks in spite of appropriate treatm ent. When suspected on th e basis of th e h istory an d physical exam in ation , laboratory tests for autoim m un e disease (rh eum atoid factor an d an tin uclear an tibodies) an d Lym e disease (ELISA) sh ould be perform ed.

Diagnosis Making the diagnosis in a limping child depends on integratin g in form ation obtain ed from th e h istory, physical exam ination, and diagnostic studies. In particular, the ch ild’s age, th e presence or absence of pain, and the type of limp are important initial clues to the diagnosis an d can help guide the diagnostic workup. For example, a painful, antalgic limp followin g traum a in an adolescen t is m ost likely due to fracture; plain radiograph s of th e affected extrem ity are usually sufficient to m ake the diagn osis. In contrast, an antalgic gait in a toddler with hip pain, fever, and m alaise

358


raises th e suspicion of in fection. An elevated ESR an d CRP level sh ould prompt an ultrasoun d of th e h ip, wh ich m ay reveal a septic effusion . Like th ese examples, m ost limps can be accurately diagn osed with a careful h istory an d physical exam in ation , followed by appropriate diagn ostic studies.

RECOMMENDED READINGS Alm an BA. Duchenne m uscular dystrophy and steroids: pharm acologic treatm ent in the absence of effective gen e therapy. J Pediatr Orthop. 2005;25(4):554 –556. Chung SM. The arterial supply of th e developing proxim al end of the h um an fem ur. J Bone Joint Surg Am. 1976;58:961 –970. Flyn n JM, Miller F. Man agem en t of h ip disorders in patien ts with cerebral palsy. J Am Acad Orthop. 2002;10:198 –209. Flyn n JM, Widm an n RF. Th e limpin g ch ild: evaluation an d diagn osis. J Am Acad Orthop. 2001;9(2):89 –98. Gillin gh am BL, Sanchez AA, Wen ger DR. Pelvic osteotom ies for th e treatm en t of h ip dysplasia in ch ildren an d youn g adults. J Am Acad Orthop. 1999;7(5):325. Heath CH, Stah eli LT. Norm al lim its of kn ee an gle in wh ite ch ildren — gen u varum an d gen u valgum . J Pediatr Orthop. 1993;13(2):259 – 262.

Sectio n 2

Herrin g JA, Kim HT, Brown e R. Legg-Calve-Perthes disease, II: prospective m ulticen ter study of th e effect of treatm en t on outcom e. J Bone Joint Surg Am. 2004;86-A(10):2121 –2134. Johnston CE. Congen ital pseudarthrosis of the tibia: results of techn ical variation s in th e Ch arn ley-William s procedure. J Bone Joint Surg Am. 2002;84:1799 –1810. Kay RM. Lower extrem ity surgery in ch ildren with cerebral palsy. In : Skaggs DL, Tolo VT, eds. Master Techniques in Orthopaedic Surgery. Philadelphia, PA: Lippincott William s & Wilkins; 2008. Lincoln TL, Suen PW. Com m on rotational variations in children. J Am Acad Orthop. 2003;11:312 –320. Misra M, Pacaud D, Petryk A, et al. Vitam in D deficiency in children and its m anagem ent: review of current knowledge an d recom m endations. Pediatrics. 2008;122:398 –417. Moseley CF. Assessm ent and prediction in leg-length discrepan cy. Instr Course Lect. 1989;38:325 –330. Pon seti IV. Growth an d developm en t of th e acetabulum in th e n orm al child: an atom ical, histological, and roentgenographic studies. J Bone Joint Surg Am. 1978;60:575. Rauch F, Glorieux FH. Osteogenesis im perfecta. Lancet. 2004;363: 1377 –1385. Skaggs DL, Flyn n JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott William s & Wilkins; 2006. Stout JL, Gage JR, Sch warz, et al. Distal fem oral exten sion osteotom y and patellar tendon advancem ent to treat persisten t crouch gait in cerebral palsy. J Bone Joint Surg Am. 2008;90:2470 –2484.

Pediatric Spine Wudbhav N. San k ar

Th e pediatric spin e presen ts several issues th at differ from those in adults. Deform ity, rather th an degeneration, is the com m on complaint. Scoliosis or kyphosis can be due to idiopath ic, n eurom uscular, or con gen ital causes. Certain cervical spine anom alies are congen ital and usually present durin g ch ildh ood; th ese in clude Klippel–Feil syndrom e an d torticollis. On e com m on complain t between adults an d ch ildren is back pain , an d a careful workup sh ould be perform ed before th e diagn osis of m ech an ical back pain can be m ade. In particular, on e m ust rule out spondylolysis an d spon dylolisth esis as th ese con dition s often affect adolescen ts. Ch ildren h ave physical differen ces th at m ake them m ore prone to spin e traum a; proper evaluation and treatm en t of th ese in juries is essen tial to en sure a positive outcom e.

IDIOPATHIC SCOLIOSIS Scoliosis can be due to a n um ber of differen t etiologies, in cludin g n eurom uscular disease, con gen ital vertebral an om alies, collagen disorders, n eurofibrom atosis, an d spin al cord injury. Idiopathic scoliosis is th e m ost com m on form of scoliosis and is a diagnosis of exclusion, implying that n o other underlying condition is present.

David L. Sk aggs Pathophysiology Scoliosis refers to coron al or fron tal plan e curvature of the spine greater than 10 degrees. It is a complex threedim en sion al (3-D) deform ity n ot on ly in cludin g th e obvious abnorm ality in the frontal plan e but also involving alteration in sagittal plan e balance an d rotation in the transverse plane (Fig. 11.195). This com bination of abnorm alities in three planes leads to the cosm etically apparent aspects of the deform ity including shoulder and pelvis asym m etry, hypokyphosis, an d rotational prom inence of the rib or flank. Alth ough th e etiology of idiopath ic scoliosis rem ains un kn own, potential causes include abnorm alities in platelet dysfun ction, m uscle im balance, collagen structure, growth plate m echan ics, and th e central nervous system (CNS). Idiopath ic scoliosis is though t to be polygen etic; a history of scoliosis in a first-degree relative significantly increases an individual’s risk.

Classification Idiopath ic scoliosis can be divided in to in fan tile (youn ger than 3 years), juvenile (3 –10 years), an d adolescen t (older than 10 years) form s. Infantile scoliosis is extrem ely rare, m ore com m on in boys than in girls, and m ore often characterized by left th oracic curve pattern s. Juvenile scoliosis


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Figure 11.195 A three-dimensional reconstruc-

tion of a scoliotic spine demonstrating the three planes of deformity. The torsional deformity is maximal at the apex of the curvature. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

comprises between 12% and 16% of all scoliosis patients an d has sim ilar dem ographics an d presentation to adolescent scoliosis. Adolescent idiopath ic scoliosis (AIS) is the m ost com m on form of idiopathic scoliosis, with a prevalen ce of 2% to 3% in th e teen age population . Historically, AIS h as been classified by th e Kin g–Moe classification . Th is radiograph ic classification is based on th e location of the frontal plane deform ity and the relative size an d flexibility of the thoracic and lum bar compon ents. In 2001, th e Len ke classification for AIS was described (Fig. 11.196). This system is m ore complete and accoun ts for the location of the m ajor curve, the relative m agnitudes of the lesser curves, deviation of the apical lum bar vertebrae from the m idlin e, and the sagittal profile. Six patterns have been described: prim ary th oracic, double th oracic, double m ajor (th oracic/ lum bar), triple m ajor, th oracolum bar/

lum bar, an d th oracolum bar/ lum bar with a structural th oracic curve. These patterns are then m odified on the basis of th e deviation of th e apical lum bar vertebra from th e m idlin e (cen tral sacral vertical lin e [CSVL]) an d th e sagittal balan ce.

Presentation AIS occurs m ore frequen tly in girls th an in boys, by a 10:1 ratio. Patien ts are usually asymptom atic, alth ough adolescen ts m ay occasion ally com plain of m ild back pain . Pain severe en ough to require frequent m edication or causing m issed tim e from school should be thoroughly investigated for another etiology. Patients m ore often present with complain ts about th eir body im age due to th eir trunk shift or rib hump. Altern atively, trunk asym m etry

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Figure 11.196 Synopsis of the Lenke classification for adolescent idiopathic scoliosis. SRS, Scoliosis Research Society; CSVL, central sacral vertical line. (Reproduced with permission from Lenke LG, Betz RR, Harms J, et al. Adolescent idiopathic scoliosis: a new classification to determine the extent of spinal arthrodesis. J Bone Joint Surg Am. 2001;83:1169–1181.)

or un even sh oulder h eigh ts m ay be in ciden tally n oted by paren ts or pediatricians (Fig. 11.197). O ften, adolescen ts with n o complain ts are iden tified in sch ool screenin g and referred for evaluation. Patients with idiopath ic scoliosis usually do n ot presen t with n eurologic symptom s.

History and Physical Examination History sh ould focus on confirm ing the diagnosis of idiopath ic scoliosis an d assessin g th e degree of physical m aturity. Patien ts sh ould be question ed about paresth esias, weakness, stum blin g or clum siness, and bowel or bladder dysfun ction . Oth er im portan t aspects of th e h istory in clude any fam ily h istory of spin al deform ity, th e patien t’s overall m edical con dition , an d th e patien t’s physiologic m aturity, in cludin g th e presen ce of pubic h air (Tan n er stage) an d th e on set of m en arch e.

Patients should be exam ined in a gown (open in the back), with sh oes an d socks rem oved. Th e skin sh ould be exam in ed for m idlin e defects, clefts, dim ples, h airy patch es, or café au lait spots. In the standing position, sym m etry of th e sh oulders, scapula, and pelvis sh ould be assessed, as should the overall coronal an d sagittal balance. The Adam s forward bending test, in which patients ben d over to touch th eir toes, reveals th e degree of rotational deform ity (rib hump) and is helpful in detecting subtle cases of scoliosis (Fig. 11.198). The lower extrem ities sh ould be evaluated for h am string tightness, asym m etric m uscular girth , an d foot deform ity; abn orm al fin din gs m ay be evidence of an underlyin g intraspinal abnorm ality. A popliteal an gle of greater th an 50 degrees implies very tight ham strings and suggests an underlying neurologic or m uscular path ology. Th is fin din g is very sen sitive but n ot very specific. A thorough neurologic testing should be perform ed, including an evaluation of light touch sensation ,

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m otor strength, lower extrem ity ton e, and deep ten don reflexes. Babin ski sign sh ould be sough t an d th e abdom in al reflex routin ely tested. Th is latter reflex is assessed by ligh tly strokin g the abdom en on either side of the um bilicus with a blun t in strum en t; a n orm al respon se con sists of a sym m etric un ilateral con traction of th e abdom in al m uscles toward th e side bein g stim ulated. Any eviden ce of upper m otor n euron pathology or asym m etry in fin din gs from on e leg to th e other calls into question the diagnosis of idiopathic scoliosis an d sh ould be in vestigated further.

Radiographs

Figure 11.197 Careful examination of the back is required to

identify the physical features of scoliosis. These include asymmetry of the scapulae, shift of the trunk, and asymmetry of the waistline, as well as asymmetry in the level of the shoulders. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

In itial radiograph ic evaluation of a patien t with spin al deform ity consists of standin g posteroan terior (PA) and lateral views on a sin gle, lon g cassette. Gen erally, th e PA view is preferred over the an teroposterior (AP) view to lim it th e am oun t of radiation exposure to th e breast tissue. Th e fron tal view is repeated at regular intervals (usually 3 –6 m onths) depending on the age an d growth velocity of th e ch ild to determ in e curve progression ; an in crease of at least 5 degrees is gen erally accepted as evidence of curve progression . Lateral views are im portan t in itially to assess th e sagittal balan ce an d to look for coexistin g spon dylolysis but are n ot necessary at each follow-up visit. Bending x-rays are h elpful for assessin g curve flexibility an d plan n in g fusion levels but are in dicated on ly as preoperative studies (Fig. 11.199).

B

Figure 11.198 (A) Viewed from the back, the deformity as-

A

sociated with this girl’s scoliosis appears mild. (B) The Adams forward bending test reveals the rotational deformity. (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, CA.)

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A,B

C

Figure 11.199 The standing posteroanterior ra-

D

Curve m agn itude is quan tified by m easurin g th e Cobb an gle of a given curve (Fig. 11.200). Typical idiopath ic curves are right thoracic and left lum bar. Coron al balance can be determ ined by evaluating the position of the CSVL relative to th e spin e. In a balan ced spin e, th e CSVL sh ould m eet the C7 plum b line. In the sagittal plane, Cobb m easurem en ts can also be used to determ in e the degree of thoracic kyphosis an d lum bar lordosis. Norm al values for thoracic kyphosis are 20 degrees to 45 degrees and lum bar lordosis is norm ally between 30 and 60 degrees. Gen erally, idiopathic scoliosis results in hypokyphosis of the thoracic spin e. Transverse plane deform ities are m ore difficult to assess on 2-D im ages, but the Nash –Moe tech n ique tries to

diograph demonstrates right thoracic scoliosis with moderate left lumbar scoliosis. (B) The flexibility of the left upper thoracic and left lumbar curves was assessed via the left-side-bending radiograph. (C) The flexibility of the right thoracic curve was evaluated using the bolster side-bending technique. (D) The bolster side-bending film is taken with the trunk laterally flexed on a bolster positioned under the ribs that correspond to the apex of the deformity. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

quan tify th e degree of rotation by evaluatin g th e am oun t of overlap between th e pedicles an d th e vertebral bodies. Th e Risser sign is a m easure of skeletal m aturity an d is based on th e degree of ossification of th e iliac crest apophysis, wh ich proceeds from lateral to m edial (Fig. 11.201). In in fan tile idiopath ic scoliosis, it is importan t to m easure the rib vertebral an gle difference (RVAD) of Meh ta (Fig. 11.202) as th is can h elp predict th e risk of curve progression. An RVAD of less than 20 degrees has been sh own to be stron gly predictive of curve resolution , wh ereas an RVAD greater th an 20 degrees is m ore likely to progress. Meh ta h as also reported th at overlappin g of th e rib h ead with the vertebral body is a poor prognostic sign.


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C7

C7 plumbline

Cobb angle thoracic curve

CSVL

Cobb angle lumbar curve

L5

Figure 11.200 Schematic of Cobb angle measure-

ments and central sacral vertical line (CSVL). Coronal compensation exists when the C7 plumb line and the central sacral vertical line meet. The stable vertebrae are bisected by the CSVL. (Adapted from Mason DE, Carango P. Spinal decompensation in Cotrel-Dubousset instrumentation. Spine 1991;16(suppl 8):S394–S403.)

Special Tests

Differential Diagnosis

Computed tom ography (CT) scans are generally unnecessary in idiopath ic scoliosis but are useful for oth er diagn oses such as con gen ital scoliosis an d osteoid osteom a. Magn etic reson an ce im agin g (MRI) is th e diagn ostic m odality of choice for all in traspinal an om alies and spinal cord tum ors. Most surgeons obtain an MRI of the full spine in young patients (younger than 10 years), patients with a history of significant pain, and those ch ildren with objective fin din gs of n eurologic dysfun ction to rule out an un derlyin g n eural axis abn orm ality. In addition , atypical curve patterns (e.g., left thoracic curves, hyperkyphosis) an d rapidly progressive curves should be evaluated with an MRI.

Idiopath ic scoliosis is a diagn osis of exclusion an d implies th at n o oth er un derlyin g con dition is presen t. O th er poten tial causes of scoliosis in clude n eurom uscular disease, con gen ital vertebral m alform ation s, collagen disorders, n eurofibrom atosis, an d spin al cord in jury. Acareful history and physical exam ination should be sufficient to identify oth er causes for scoliosis, alth ough an MRI m ay be n ecessary to rule out un derlying conditions.

Natural History Th e risk of deform ity progression depen ds on th e am oun t of growth rem ain in g an d th e size of th e curve. Durin g

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3

4 5

2 1

Figure 11.201 Risser sign. The iliac apophysis ossifies in a pre-

dictable manner beginning laterally and progressing medially. The capping of the iliac crest is correlated with slowing and completion of growth, generally occurring over a period of 18 to 24 months. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

periods of rapid growth velocity, such as th e adolescen t growth spurt, curves can progress an average of 1 degree per m on th . As a result, age at m en arch e, Tan n er stage, Risser sign , an d oth er assessm en ts of physical m aturity are importan t for predictin g th e beh avior of a curve an d for plan n in g appropriate treatm en t. In creasin g curve m agn itude also raises th e risk for progression ; double curves are m ore likely to progress th an sin gle curves. In gen eral, curves less th an 50 degrees ten d to rem ain stable after skeletal m aturity, wh ereas curves greater th an 50 degrees con tin ue to progress 1 degree per year th rough adulth ood. Natural h istory studies h ave dem on strated th at un treated AIS results in a sligh tly h igh er in ciden ce of back pain an d altered body im age later in adulth ood compared with con trols. Altered pulm on ary fun ction (based on pulm on ary fun ction tests) can be seen in curves greater than 60 degrees to 70 degrees an d life expectan cy m ay be decreased in curves greater th an 100 degrees.

B A

RVAD = A − B

Figure 11.202 The rib vertebral angle difference (RVAD) is measured by determining the angle of the right and left ribs at the apical vertebra. The slope of the ribs relative to the transverse plane is measured for each rib. The difference in the angle between the right and left sides is the RVAD. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Figure 11.203 Serial casting is often used for the treatment

of progressive infantile idiopathic scoliosis. This demonstrates a method of applying a bending force by suspending the trunk with muslin before rolling a Gore-tex lined fiberglass cast. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Treatment In fan tile idiopath ic scoliosis with an RVAD less th an 20 degrees is typically observed, alth ough treatm en t is often instituted if a progression beyond 30 degrees is noted. Ch ildren with progressive in fan tile scoliosis or an RVAD greater than 20 degrees m ay be treated with serial corrective casting un der gen eral an esth esia (Fig. 11.203). Th ese growin g ch ildren usually require cast ch an ges every 3 m on th s. Wh en the curve has been corrected an d m aintained at less than 10 degrees, full-tim e bracin g is in stituted. In juven ile scoliosis, several studies have shown continued curve progression in spite of brace use. In certain cases, however, bracing m ay lim it th e rate of curve progression and m ay be effective in delaying the need for surgical intervention. As a result, bracing of juven iles is often con tinued even in larger curves to allow furth er trunk growth, recognizing that surgical treatm en t will be needed in the future. In children with progressive in fan tile an d juven ile scoliosis th at h ave failed n on surgical treatm en t, early lon g segm en t spin al fusion is generally avoided because it can drastically affect trunk heigh t and pulm onary fun ction. Instead, m ost surgeon s favor th e use of “growin g’’ in strum en tation with out fusion, which allows serial len gthenings in the operating room to ach ieve in creased spin al len gth (Fig. 11.204). Th e prim ary goal of treatm en t in AIS is to con trol curve progression an d allow ch ildren to en ter adulth ood with a stable spine. Observation is indicated for patien ts with sm aller curves (< 25 degrees) an d older adolescen ts (Risser III, IV, or V) with lim ited growth rem ain in g. O bservation is also appropriate for adolescen ts with significant curves wh o m ay have gone beyon d the suitable ran ge for bracin g but are n ot yet can didates for surgical treatm en t.

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B

A

Figure 11.204 (A, B) Posteroanterior (PA)

and lateral radiograph of a 5-year-old boy with juvenile idiopathic scoliosis and an 82degree spinal deformity. (C, D) PA and lateral radiographs after treatment with growing rod spinal instrumentation. (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, CA.)

C

Th is would in clude curves of approxim ately 40 degrees or 45 degrees in skeletally m ature adolescen ts (Risser III, IV, or V), curves th at h ave n ot been docum en ted to progress, or well-balan ced double m ajor curves between 40 degrees an d 50 degrees that are cosm etically unobjectionable in a patient wh o is near the en d of growth. Patients being observed sh ould be followed closely for curve progression , especially durin g tim es of rapid growth . Bracin g as a treatm en t for AIS rem ain s con troversial. Previous studies h ave been lim ited by unpredictable com plian ce, variable spin al orth oses, an d un con trolled study design s. Neverth eless, bracin g is still th e m ost com m on

D

n on surgical treatm en t m odality for AIS. Spin al orthoses provide a th ree-poin t m old to ach ieve curve correction an d require con tin ued growth to gradually con trol spin al deform ity. Th e goal of treatm en t is to preven t th e deform ity from worsening; improvem ent of the curve, while it can occur, sh ould n ot be expected. Braces are generally prescribed for curves between 25 degrees an d 40 degrees in adolescents wh o are still growin g (Risser 0, I, II). Awide variety of braces an d bracin g protocols exist. Most surgeon s favor an un derarm th oracolum bosacral orth osis (TLSO) an d recom m en d that it be worn up to 23 hours a day, allowing som e tim e out of th e brace for bath in g an d participation in sports.

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C

A,B Figure 11.205 (A) Thoracolumbosacral orthosis underarm brace. (B) Posteroanterior radiograph

demonstrates a right thoracic and left lumbar curve pattern in an adolescent with remaining growth. (C) The in-brace radiograph demonstrates a reduction of both the thoracic and lumbar curves. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

After the brace has been worn for 1 m onth, a radiograph sh ould be taken in th e brace to determ in e th e am oun t of curve correction since the prognosis for ultim ate success is depen den t on th e in itial respon se to bracin g (Fig. 11.205). Bracin g is discontinued when curves reach surgical dim en sion s (45 degrees–50 degrees) or wh en skeletal m aturity has been reached. Surgery is gen erally in dicated for skeletally im m ature patien ts wh o, despite bracin g, h ave docum en ted progression beyond 45 degrees an d for skeletally m ature adolescents with curves greater than 50 degrees. Th ese guidelin es are based on clear eviden ce th at un treated curves greater than 50 degrees will continue to progress through adulthood while th ose less than 50 degrees will likely rem ain stable. For adolescen ts at or n ear skeletal m aturity, th e stan dard of care is segm en tal posterior spin al in strum en tation an d fusion (Fig. 11.206). The selection of fusion levels depends on th e curve pattern , th e m agn itude of th e curve, an d th e flexibility of the m inor curves. Instrum entation generally spans th e entire fusion , usually on both sides of th e spin e. Hooks, wires, or pedicle screws can be used to achieve segm en tal fixation . Th e placem en t of in strum en tation poste-

rior to th e axis of th e spin e can create a lordosin g effect; as a result, care sh ould be taken to release sufficien t tissue an d appropriately bend the rods to preserve thoracic kyphosis. Correction of 50% or m ore with a pseudarthrosis rate of 2% to 3% an d a 0.5% risk of n eurologic com plication s can be expected. Release of th e an terior lon gitudin al ligam en t and discs (either open or thoracoscopically) can be used as an adjun ct to posterior spinal fusion in larger, stiffer curves, alth ough the use of m odern pedicle screw instrum entation h as reduced th e need for th is. Anterior fusion with anterior in strum entation has been proposed for certain th oracolum bar an d lum bar curves as a m ean s of “savin g’’ distal fusion levels (Fig. 11.207). Th is approach requires a flexible m ajor curve and a flexible m in or curve with docum en ted ability of th e distal fusion level to approach horizon tal on bending radiographs. Thoracic curves can also be treated by an terior in strum en tation an d fusion through either an open thoracotomy or a thoracoscopic approach. Con cern s about the pulm on ary impact of both exposures h ave quelled som e of th e en th usiasm for th is tech n ique. Crankshaft phenomenon is defin ed as continued progression of the scoliotic deform ity due to persisten t an terior growth after a posterior-only spin al fusion.


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A

B

C

D

Com bined anterior fusion and posterior fusion and instrum en tation have classically been indicated for severe curves an d in ch ildren younger than 10 years to m inim ize the risk of cran ksh aft. Th e use of m odern pedicle screw in strum en tation allows for greater curve correction an d m ay decrease the risk of cran kshaft with a posterior-only approach.

functional deterioration of the patient. Recognition of th e risk of spinal deform ity, knowledge of the natural history, an d in tegration of th ese with patien ts’overall fun ction an d progn osis lead to appropriate decision m akin g.

Figure 11.206 (A, B) Posteroanterior (PA) and lateral ra-

diographs of a 16-year-old boy with Lenke 3 adolescent idiopathic scoliosis. The thoracic curve measures 53 degrees and the lumbar curve measures 60 degrees. (C, D) Postoperative PA and lateral radiographs after posterior spinal instrumentation and fusion. (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, CA.)

NEUROMUSCULAR SCOLIOSIS A n um ber of n eurom uscular con dition s are seen in wh ich scoliosis is com m on an d contributes significan tly to the

Pathophysiology and Classification Th e exact etiology of n eurom uscular scoliosis is poorly un derstood an d likely depen ds on th e un derlyin g con dition . In m ost cases, abn orm al m uscle forces about th e spin e from increased spasticity (e.g., cerebral palsy) or m uscle weakn ess (e.g., spinal m uscular atrophy, m uscular dystrophy)

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Figure 11.207 (A) Schematic of a single-

A

lead to progressive deform ity. Neurom uscular scoliosis h as been classified by th e Scoliosis Research Society as either neuropathic or myopath ic. Neuropath ic conditions in clude upper m otor n euron or lower m otor n euron abn orm alities. Th e m ost com m on upper m otor n euron conditions include Friedrich ataxia, Charcot–Marie–Tooth disease, an d abn orm alities of th e spin al cord such as syringomyelia and spinal cord tum ors or traum a. Lower m otor n euron con dition s in clude poliomyelitis an d spin al m uscular atrophy. Myopath ic con dition s in clude arth rogryposis, con gen ital hypoton ia, an d, m ost im portan tly, m uscular dystrophy.

Presentation Neurom uscular scoliosis m ay be diagn osed early in ch ildren wh o are followed for oth er orth opaedic issues related to th eir un derlyin g con dition . Altern atively, patien ts m ay presen t later with m ore advan ced deform ity. Th ese patien ts gen erally com plain of difficulty sittin g due to trun cal im -

B

rod anterior construct used for thoracic scoliosis correction. Note the structural grafting of the lower two levels. (B) Dual-rod constructs are generally preferred for thoracolumbar scoliosis. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

balan ce an d/ or pelvic obliquity. In severe cases, isch ial ulcers can occur from asym m etric loadin g. In ch ildren with n orm al cognition, th e ability to freely use th e upper extrem ities and function independently in a wheelchair m ay be com prom ised by worsen in g scoliosis. Fam ilies with h igh ly involved children often complain that transfers, positioning, and bathing are difficult. Pain m ay or m ay not be associated with neurom uscular scoliosis and is often difficult to assess, particularly in patien ts with cerebral palsy.

History and Physical Examination Evaluation of a patien t with n eurom uscular spin al deform ity includes assessm ent of the patien t’s intellectual skills, com m unication skills, and sittin g capabilities. Th e presence of con tractures, particularly about th e h ip, or pelvic obliquity sh ould be n oted. Th e skin is carefully assessed for turgor and for any areas of skin breakdown, especially in the ischium . It is essential to evaluate the impact of the curve on th e ch ild’s ability to sit (Fig. 11.208). In addition to


A

369

B Figure 11.208 Clinical (A) and radiographic (B) images of a girl with neuromuscular scoliosis due

to cerebral palsy. Note the sitting imbalance and pelvic obliquity. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

exam in in g th e coron al sittin g balan ce an d pelvic obliquity, careful attention m ust be paid to sagittal plan e problem s wh en seated; m any patien ts with poor m uscle ton e lack head and trunk con trol an d have a ten dency to fall forward. Th e m agn itude of th e deform ity in both th e fron tal an d sagittal plane should be assessed clin ically, as should the flexibility of th e curve. It is importan t wh en evaluatin g a ch ild with n eurom uscular scoliosis to assess the cardiopulm on ary function an d the nutritional status. Patien ts with neurom uscular curves are at risk for, or already have, cardiopulm onary dysfunction. Th is is frequently exacerbated by alterations in the ch est cage seen with scoliosis. These ch ildren should be referred for cardiac and pulm onary evaluations to accurately assess the risk of complications and prolon ged intubation after surgery. Form al consultation with a nutrition ist, if there is any question about the patient’s protein balan ce and caloric intake, is frequently very helpful. Potential surgery should be deferred until a positive nitrogen balan ce has been ach ieved to help avoid catastrophic woun d com plication s. At tim es, th is m ay require th e placem en t of a gastrostomy tube to aid in nutrition prior to spine surgery.

Radiographs As in cases of idiopath ic scoliosis, lon g-cassette AP an d lateral radiograph s are n ecessary to evaluate n eurom uscular spin al deform ity. Often these patients are n onam bulatory, so radiographs m ust be perform ed in the seated position (Fig. 11.209). This is preferred over supine radiographs, wh ich can drastically un derestim ate th e degree of spin al deform ity. In addition to usin g th e Cobb an gle to quan tify th e severity of th e curve, on e sh ould assess pelvic obliquity by m easuring the angle between the horizontal and a lin e tangen tial to the iliac crests (Fig. 11.210). Flexibility is best assessed with traction radiographs since bendin g radiograph s are often difficult to obtain in th is patien t population .

Special Tests CT scans are usually not n ecessary unless there is a suspicion of a con gen ital vertebral an om aly. O ccasion ally, CT scan s can be h elpful in cases of myelodysplasia to determ in e th e presen ce or absen ce of posterior elem en ts.

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A,B

C Figure 11.209 (A, B) Seated posteroanterior and lateral radiographs of a 10-year-old boy with

a mitochondrial disorder and neuromuscular scoliosis. Note the severe thoracolumbar scoliosis and pelvic obliquity. (C) In these patients, traction x-rays are superior to bending x-rays to assess curve flexibility. (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, CA.)

MRI is in dicated for n eural axis abn orm alities (e.g., syringomyelia) and for cases with m ore rapid curve progression th an would otherwise be suspected for th e particular condition.

Differential Diagnosis Th e differen tial diagn osis for n eurom uscular scoliosis in cludes idiopath ic scoliosis, congenital scoliosis, and spinal deform ity due to con n ective tissue disorders (e.g., Marfan syn drom e, Eh lers–Dan los syn drom e). Any spin al deform ity in the presence of an underlying neurom uscular disorder can be diagn osed as n eurom uscular scoliosis.

Treatment Non operative treatm en t m ay in clude observation , seatin g support system s, or bracin g. Observation is appropriate for m ild curves without functional impairm en t. These children , h owever, sh ould be closely followed, as m ost are at relatively h igh risk for progression . Th e risk of progression is greatest in patien ts with spastic quadriplegia, particularly those who are n onam bulators. Seating support system s are extrem ely useful for m an agin g m ild to m oderate deform ities. A well-m ade support system can accom m odate pelvic obliquity, m in im ize th e risk of skin com plication s, provide assistan ce in sittin g balan ce, an d even assist with h ead con trol (Fig. 11.211). Bracin g is con troversial for neurom uscular spin al deform ity. It is gen erally accepted th at bracin g is in effective for correctin g spin al deform ity. O ccasion ally,

h owever, curve progression can be h alted or at least slowed by a spinal orthosis. More com m only, bracing is employed for young ch ildren and for those who n eed som e assistan ce to sit uprigh t. Surgical treatm en t is in dicated for progressive curves greater th an 60 degrees th at are adversely affectin g a ch ild’s quality of life. In ch ildren with Duch en n e m uscular dystrophy, th e cardiopulm on ary system can deteriorate rapidly with worsen in g spin al deform ity. As a result, surgery is in dicated for curves greater th an approxim ately 30 degrees before th e patien ts are too com prom ised to tolerate spin al surgery. Surgical treatm en t of n eurom uscular scoliosis con sists of a posterior spin al fusion with segm en tal in strum en tation. The issues to be addressed by th e surgeon in clude wh eth er or n ot to exten d th e fusion to th e pelvis, th e type of segm en tal in strum en tation utilized, an d wh eth er or n ot circum feren tial fusion is n ecessary. Fusion to th e pelvis is indicated in neuropath ic curves such as cerebral palsy in th e presen ce of fixed pelvic obliquity. Fusion to th e pelvis sh ould be avoided in am bulators if possible, as this m ay decrease th e patien t’s am bulatory status. Several option s exist for ach ievin g pelvic fixation , in cludin g th e Galveston tech n ique (custom ben t rod with pelvic lim bs), un it rod (prebent continuous rod with pelvic lim bs), and iliac bolts (Fig. 11.212). Circum ferential anterior and posterior fusion h as traditionally been advocated for curves at risk for the developm ent of crankshaft phen om enon, for nonun ion, and for curves th at are very large (greater th an 90 degrees–100 degrees), very rigid, or in volve sign ifican t kyph osis such


371

Cobb angle

Pelvic obliquity

Figure 11.211 An appropriately fitted wheelchair provides

proper body positioning, including head control. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

CONGENITAL SPINAL ANOMALIES

Figure 11.210 Measurement of pelvic obliquity.

that posterior instrum entation alone is unlikely to result in adequate align m ent. Th e results of surgery for n eurom uscular spin al deform ities have varied am ong authors and are dependent on the un derlyin g disorder. Curve correction between 50% an d 75% h as been reported for patien ts with cerebral palsy; with the use of banked allograft bone, a pseudarthrosis rate of 5% to 10% m ay be expected. Fusion to th e pelvis gen erally results in lon g-lastin g improvem en t in fixed pelvic obliquity an d sittin g balan ce in m ost patien ts. Com plication s are not uncom m on in these patients, however, and in clude woun d breakdown , deep in fection , an d n on un ion leadin g at tim es to instrum entation failure.

Congenital anom alous vertebrae m ay lead to the developm ent of spinal deform ities. Th ese deform ities range from m ild to severe an d are am on g th e types of spin al deform ity that are m ost likely to lead to n eurologic impairm ent and even paraplegia. Because of th e propensity for certain types of congen ital spinal deform ity to progress rapidly, because of th e risk of n eurologic impairm en t an d in traspin al anom alies, and because of th e association of congenital spin al deform ity with congenital an om alies of other organ system s, all orthopaedic surgeons sh ould be aware of th e im plication s of con gen ital deform ity of th e spin e wh en recogn ized.

Pathophysiology and Classification Th e specific etiology of con gen ital spin e deform ities rem ain s largely un kn own . Vertebral m alform ation s are th ough t to arise from a gen e disruption durin g som atogen esis, th e process by wh ich th e axial skeleton is form ed durin g em bryogen esis, or from en viron m en tal in sults sustain ed durin g gestation . Con gen ital deform ities of th e spin e are categorized by the plane of deform ity (scoliosis, kyph osis, or kyph oscoliosis) and the specific type of

372


tebrae can also be described as in carcerated if th e lateral border of th e h em ivertebra is in lin e with or m edial to a lin e drawn along the lateral border of the vertebral body above and below. Type II anom alies (failure of segm entation) lead to a fibrous or bony bar between adjacent vertebrae. Bilateral failure of segm en tation results in a block vertebra; unilateral segm en tation defects result in a unilateral bar on th e con cave side of th e curve. Mixed an om alies (type III) are the m ost com m on type of congen ital spin al deform ity.

Presentation

A

B

Th e in ciden ce of con gen ital scoliosis in th e gen eral population is estim ated between 1% and 4%; congenital kyphosis is even rarer. Most children with congenital spine deform ities present at an early age, and m ost are asymptom atic. Youn g ch ildren m ay presen t with a m ild deform ity or with an om alies that were found in cidentally on radiographs taken for oth er reason s. In advan ced cases (especially severe con genital kyphosis), patients m ay presen t with neurologic deficits.

History and Physical Examination

C

D

Figure 11.212 (A, B) Seated posteroanterior (PA) and lateral

radiographs of a 13-year-old boy with neuromuscular scoliosis and pelvic obliquity due to Duchenne muscular dystrophy. (C, D) PA and lateral radiographs after posterior spinal instrumentation and fusion using the Galveston technique for pelvic fixation. (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, CA.)

vertebral an om aly or an om alies. Vertebral m alform ation s are classified as eith er failure of form ation (type I), failure of segm en tation (type II), or m ixed an om alies (type III) (Fig. 11.213). Failure of form ation usually leads to a h em ivertebra. Hem ivertebrae can be com pletely segm en ted, m ean in g th ere is disk tissue separatin g th e an om alous vertebra from both th e vertebra above an d below it; sem isegm ented, m ean ing disk tissue is present either above or below th e h em ivertebra; or n on segm en ted, m ean in g it is attach ed to both th e vertebra above an d below. Hem iver-

Physical exam in ation sh ould in clude evaluation of spin e an d sh oulder sym m etry, overall balance, an d cervical, thoracic, an d lum bar flexibility. Neck ran ge of m otion an d scapular h eight sh ould be assessed because of the strong association of congenital spinal deform ity with Klippel– Feil syn drom e an d Spren gel deform ity. Acareful n eurologic exam in ation in cludin g sen sation , m otor stren gth , an d reflexes is warranted in all children with congenital spine deform ity. Neurologic deficits can be due to th e vertebral an om alies th em selves or from an associated spinal dysraph ism th at exists in 20% to 40% of ch ildren with con gen ital spin al deform ity. Th e m ost com m on n eural axis abn orm ality is a tethered cord, but Chiari type I m alform ations, diastem atomyelia, syrin gomyelia, or a low conus can also be seen . Physical findings associated with an intraspinal anom aly include a cavus foot, hairy patches, dim ples, n evi, or asym m etrical or absen t abdom in al reflexes. In addition to th e association with n eural axis abn orm alities, congenital spin al deform ity is frequently associated with defects in other organ system s. The incidence of coexisting congenital heart disease (particularly ventricular or atrial septal defects an d paten t ductus arteriosus) is approxim ately 10%. As a result, all patien ts with con gen ital spin al deform ity sh ould be referred for a cardiac evaluation and an echocardiogram if indicated. Approxim ately 25% to 40% of patien ts with con gen ital spin e deform ity h ave anom alies of the gen itourin ary (GU) tract, the m ost com m on of which is unilateral ren al agenesis. An MRI of the kidn eys or renal ultrasound should, therefore, be perform ed on m ost patients.


Defects of segmentation Block vertebra

Unilateral bar

Unilateral bar and hemivertebra

Unilateral failure of segmentation

Bilateral failure of segmentation

Defects of formation Hemivertebra

Wedge vertebra

Unilateral complete failure of formation

A

Fully segmented

Defects of vertebral-body segmentation

B

Unilateral partial failure of formation

Semisegmented

Incarcerated

Nonsegmented

Defects of vertebral-body formation

Partial

Anterior and unilateral aplasia

Anterior and median aplasia

Anterior unsegmented bar

Posterolateral quadrant vertebra

Butterfly vertebra

Complete

Anterior aplasia

Anterior hypoplasia

Block vertebra

Posterior hemivertebra

Wedge vertebra

Mixed anomalies

Anterolateral bar and contralateral quadrant vertebra

Figure 11.213 Classification of congenital scoliosis. (Reproduced with permission from Morrissy

RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

373

374


Figure 11.214 (A) Anteroposterior spinal radiograph

demonstrating a L1 hemivertebra. (B) Three-dimensional computed tomography reconstruction more clearly defines the nature of the hemivertebra. (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, CA.)

A

B

Radiographs

liosis. VATER syndrom e (Vertebral anom alies, Anorectal anom alies, TracheoEsophageal fistula, an d Renal and vascular abn orm alities) an d Golden h ar syn drom e (ocular, auricular, an d vertebral defects) can both be associated with vertebral body m alform ations and scoliosis. Usually, the presen ce of th e associated organ system an om alies h elps distin guish isolated con gen ital scoliosis from th ese oth er diagn oses. Idiopath ic scoliosis, especially in fan tile an d juvenile form s, can occur in a sim ilar age group as congen ital scoliosis. In idiopath ic scoliosis, however, radiographs do n ot dem onstrate any defects in vertebral segm en tation or form ation. Th e differen tial diagnosis of kyphosis in young children includes postinfectious kyphosis, achondroplasia, Scheuerm an n kyphosis, and traum a.

Th e in itial diagn ostic tests of ch oice are h igh -quality radiograph s of th e en tire spin e. Careful evaluation of th e vertebrae an d disk spaces is importan t to defin e th e area of spin e in volvem en t an d to determ ine the specific pattern of deform ity (Fig. 11.214). Iden tifyin g on e vertebral an om aly sh ould prompt a search for oth er contiguous and n oncon tiguous m alform ation s. Th e overall radiograph ic balan ce of th e spin e sh ould be assessed. For exam ple, con tralateral h em ivertebrae can result in a relatively balan ced curve an d a stable spin e deform ity. In addition to evaluatin g th e coronal plane deform ity, it is essential to obtain lateral radiograph s to adequately exam in e th e sagittal plan e. Kyph osis, not scoliosis, is the m ost con cern in g type of congen ital spin al deform ity due to its h igh risk for neurologic com plications.

Special Tests CT scan is th e diagn ostic m odality of ch oice for evaluatin g bony an atomy an d is extrem ely useful for elucidatin g vertebral m alform ation s th at can often be difficult to defin e on the basis of plain radiographs. In particular, CT scans with 3-D recon struction s can be very h elpful for un derstan din g abn orm al an atomy an d plan n in g corrective surgery. MRI is in dicated in all ch ildren with con gen ital spin al deform ity to rule out an intraspinal anom aly (Fig. 11.215). As m en tion ed, ren al ultrasoun d an d ech ocardiogram m ay be necessary to look for coexistin g GU or cardiac abnorm alities.

Differential Diagnosis Th e differen tial diagn osis of isolated con gen ital scoliosis in cludes scoliosis due to syn drom es an d idiopath ic sco-

Treatment Treatm ent of congen ital spinal deform ity is determ ined by the natural history of the specific anom alies present, an assessm ent of th e potential for curve progression, and the risk of n eurologic deterioration . McMaster an d O h tsuka, in a large review, dem onstrated significant progression in 75% of th eir patien ts. Both th e region of th e spin e an d th e type of anom aly impacted on the risk of progression (Table 11.7). The worst prognosis was seen in patients with a unilateral unsegm ented bar opposite a hem ivertebra, although an isolated unilateral unsegm ented bar was also at significant risk for progression. The best prognosis was seen with isolated hem ivertebra, particularly incarcerated, sem isegm en ted, and nonsegm ented hem ivertebrae. Defects at the thoracolum bar junction had a higher risk of progression than elsewh ere; h owever, because of the impact on shoulder balan ce, defects in th e upper th oracic an d cervicoth oracic spin e resulted in th e m ost readily apparen t clin ical deform ities seen .


A

C

D

B Figure 11.215 (A) Intraspinal anomalies accompanying vertebral anomalies are common. Indications for magnetic resonance imaging include planned surgical intervention, abnormalities found on neurologic examination, and progressive curvature in the unaffected section of the spine. Diplomyelia is visible in this computed tomography (CT) myelogram. (B) Diastematomyelia, diplomyelia, tethered spinal cord, and other anomalies are present in this infant with multiple vertebral anomalies. (C) Tethered spinal cord with thickened filum terminale. (D) A CT scan with three-dimensional reconstruction is helpful to understand the details of congenital vertebral anomalies. Two lumbar hemivertebrae are readily visible here. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

375

376


TABLE 11.7

LIKELIHOOD OF PROGRESSION OF CONGENITAL SCOLIOSIS ASSOCIATED WITH DIFFERENT VERTEBRAL ANOMALIES, BASED ON ANNUAL RATE OF PROGRESSION Type of Congenital Anomaly Site of Curvature Up p e r thoracic Lowe r thoracic Thoracolumb ar Lumb ar Lumb osacral

Block Vertebra

Wedge Vertebra

< 1 ◦ –1 ◦ < 1 ◦ –1 ◦ < 1 ◦ –1 ◦ < 1◦ –

–2 ◦ 2 ◦ –3 ◦ 1.5 ◦ –2 ◦ < 1◦ –

Hemivertebra Single

Double

1 ◦ –2 ◦ 2 ◦ –2.5 ◦ 2 ◦ –3.5 ◦ < 1 ◦ –1 ◦ < 1 ◦ –1.5 ◦

2 ◦ –2.5 ◦ 2 ◦ –3 ◦ 5◦ –

No treatment required May require spinal surgery Require spinal fusion Ranges represent the degree of derotation before and after 10 years of age.

The natural history of con genital kyphosis also depen ds on th e type of vertebral an om alies an d th e age of th e patient. Type III (m ixed an om alies) m alform ation s usually result in th e m ost rapid curve progression , followed by type I m alform ation s. O f all con gen ital spin al deform ities, con genital kyph osis h as th e h igh est risk of n eurologic com prom ise (Fig. 11.216).

Figure 11.216 Congenital kyphosis has the highest risk of neu-

rologic impairment. Sagittal magnetic resonance imaging view of a 4-year-old boy who presented with myelopathy. The spinal cord is draped across the apex of the deformity. (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, CA.)

Unilateral Unsegmented Bar 2 ◦ –4 ◦ 5 ◦ –6.5 ◦ 6 ◦ –9 ◦ > 5◦ –

Unilateral Unsegmented Bar and Contralateral Hemivertebrae 5 ◦ –6 ◦ 6 ◦ –7 ◦ > 10 ◦ –

Too few or no curves.

Ch ildren with m ild spin al deform ity an d a favorable n atural h istory can be followed with serial radiograph s un til skeletal m aturity. Th e frequen cy of radiographic evaluation depen ds on th e risk of curve progression an d th e patien t’s age. Con genital curves are usually less flexible than idiopath ic curves; an d th erefore, bracin g is rarely effective in controllin g th e prim ary curve. Occasion ally, bracin g can be h elpful for m an agin g compen satory curves. In con gen ital scoliosis, surgery is in dicated to h alt progressive deform ity an d spin al im balan ce. All surgical procedures in volve som e am oun t of spin al fusion an d can potentially decrease th e overall spin e len gth in th ese growin g children. The risks of lim iting growth potential, however, m ust be compared with the risks of continued asym m etric growth an d worsen in g spin al deform ity. Early, lim ited in situ fusion can stop curve progression with relatively low risk of complications. For younger children , a com bined an terior an d posterior arth rodesis sh ould be con sidered to m in im ize th e risk of cran ksh aft ph en om en on . In sm aller ch ildren , postoperative im m obilization can consist of a cast or brace. In strum en tation can be used to stabilize th e arth rodesis an d ach ieve m ore curve correction ; h owever, th e n eurologic risks of in strum en tation are h igh er in children with con genital scoliosis th an in children with idiopathic scoliosis. For ch ildren youn ger than 5 years with progressive deform ity due to a fully segm en ted h em ivertebra, con vex an terior an d posterior h em iepiphysiodesis m ay allow for continued growth on the concave side of the curve, th ereby causin g som e gradual im provem en t of th e deform ity. In m ore severe deform ities, h em ivertebra excision can be perform ed (Fig. 11.217). This procedure allows for greater correction but does carry an increased risk of n eurologic complication s. Because of their tenden cy to progress an d th e h igh risk for n eurologic deterioration , m ost cases of con gen ital kyph osis warran t surgery. Posterior fusion alon e can be perform ed in ch ildren youn ger th an 5 years with curves less th an 55 degrees, as th is can allow for som e im provem en t in


377

Figure 11.217 (A) Posteroante-

rior (PA) radiograph showing a hemivertebra between T12 and L1 that has caused scoliosis. (B) Final PA radiographs after excision of the hemivertebra and correction of the deformity. (Reproduced with permission from Skaggs DL, Tolo VT. Master Techniques in Orthopaedic Surgery: Pediatrics. Philadelphia, PA: Lippincott Williams & Wilkins, 2008.)

A

the deform ity with anterior spinal growth. Instrum en tation is often used prim arily for stabilization rather than for correction because of th e n eurologic risk associated with large correction. Anterior and posterior fusion is often necessary in older patients and in kyphosis greater than 55 degrees.

SCHEUERMANN KYPHOSIS Wh ile scoliosis refers to deform ities in th e coron al plan e, kyphosis is m easured in the sagittal plane. The norm al thoracic spin e h as sligh t kyph osis ran gin g from 20 degrees to 45 degrees (Fig. 11.218). Th e th oracolum bar spine sh ould be relatively straigh t between T10 an d L2, an d th e lum bar spine below L2 should have m ore lordosis th an th e th oracic spin e h as kyph osis. Abn orm al th oracic kyph osis can be due to m ultiple etiologies, but Sch euerm an n kyph osis is one of the m ost classic causes in an adolescent.

Pathophysiology Th e etiology of Sch euerm an n kyph osis con tin ues to be debated. Mech an ical an d m etabolic factors h ave been suggested, an d disruption of th e cartilage rin g apophysis, abn orm alities of the en dplates leading to Schm orl node form ation (herniation of disk m aterial through the endplate), an d gen etic factors h ave all been im plicated. Th ese en dplate disturban ces cause an terior wedgin g of th e vertebral bodies an d th e resultan t kyph osis.

B

Presentation Sch euerm an n kyphosis occurs in 0.4% to 8.3% of the population an d is m ore com m on in boys th an in girls. Un like juvenile form s of scoliosis, Scheuerm ann kyph osis is rarely diagn osed prior to age 10, typically presen tin g during later teenage years. Patients are usually brough t to a surgeon because of concerns on the part of the parents about hunched posture. Mild to m oderate thoracic back pain is m ore com m on in m ore severe deform ities or in deform ity of th e thoracolum bar junction or upper lum bar spin e. Natural history studies have sh own that although affected patients seem to have m ore back pain than h ealth con trols, th eir ability to perform activities of daily livin g or m aintain gainful employm en t is not altered.

Physical Examination Typical patien ts with Sch euerm an n kyph osis h ave rigid hyperkyph osis of th e m idth oracic or lower th oracic spin e. Th ere is often compen satory hyperlordosis of th e lum bar spin e. This rigidity distin guish es Scheuerm ann kyphosis from m ore benign causes such as postural kyphosis and can be assessed by position in g th e pron e patien ts on th e exam ining table and asking th em to hyperextend the back and lift th e h ead. The sagittal profile during a forward bending test often appears m ore sh arply an gulated compared with th e gen tle roun dn ess of postural kyph osis (Fig. 11.219). Associated h am strin g tigh tn ess is com m on an d sh ould be evaluated by m easurin g th e popliteal an gles (Fig. 11.220).

378


C2

C7 T1

Normal range of thoracic kyphosis = 20°–45°

Figure 11.219 In Scheuermann kyphosis, the sagittal profile appears more sharply angulated than the gentle “roundness” of postural kyphosis. (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, CA.)

T12

Normal lumbar lordosis = 40°–60°

L5

defin ition of th e disease. Lon g-cassette radiograph s sh ould also be obtained in the AP plane to evaluate for a concom itant scoliotic deform ity. A coexisting spon dylolysis sh ould be ruled out on lateral radiographs as th ese occur in increased frequency in patients with Scheuerm ann kyphosis.

Special Tests MRI is in dicated as a preoperative study to rule out any spin al cord abn orm alities. In addition, MRI is useful to evaluate th e h ealth of lum bar disks, because th e presen ce of disk degen eration m ay be th e un derlyin g cause of th e patien t’s sym ptom s an d can alter th e exten t of fusion . Figure 11.218 Normal sagittal alignment of the spine. (Adapted from Abel MF. Orthopaedic Knowledge Update: Pediatrics. Rosemont, IL: American Academy of Orthopaedic Surgeons, 2006.)

As with any condition of th e spine, a thorough neurologic exam in ation in cludin g stren gth , sen sation , an d reflexes is warranted.

Radiographs Th e classic radiograph ic criteria for diagn osin g Sch euerm an n kyph osis are (1) wedgin g of th ree adjacen t vertebrae of 5 degrees or m ore, (2) en dplate irregularity, an d (3) Sch m orl n ode form ation (Fig. 11.221). Many con sider ch an ges in a sin gle vertebral body especially in th e th oracolum bar or lum bar spine to be form s of Scheuerm ann kyph osis, even though these patients do not m eet th e strict

Differential Diagnosis Th e differen tial diagn osis for abn orm al kyph osis in cludes postural kyph osis, con gen ital kyph osis, an d posttraum atic kyphosis am ong others. The m ost com m on kyphotic disorder seen by th e orth opaedist is th e adolescen t with postural roun d back. Lon g-stan din g complain ts of “poor posture’’ are com m on and m ay have been present in oth er m em bers of th e fam ily. An appreciation of th e ten den cy of som e adolescents going through puberty to h abitually stand with roun ded sh oulders m ay explain th e perceived in crease in kyphosis. Postural roundback m ay be differentiated from Sch euerm an n kyph osis by th e lack of ch aracteristic en dplate ch an ges on radiograph s, in creased flexibility of th e spin e, and m ore generalized rounding in the sagittal plane compared with th e m ore localized, an gular appearance of


379

Figure 11.221 Lateral radiograph of a patient with ScheuerFigure 11.220 The popliteal angle is measured by flexing the hip to 90 degrees and extending the knee. The popliteal angle is the angle formed between the leg and the vertical.

Sch euerm an n kyph osis. Patien ts with postural kyph osis can be treated with observation or an exercise program focusing on core strengthening. Congen ital kyphosis can often be difficult to distin guish from Sch euerm an n kyph osis, especially in those children with failure of segm en tation whose boney bars do not appear until later in adolescen ce. Congenital kyphosis, however, ten ds to present at younger ages compared with Scheuerm ann kyphosis. Addition al studies such as MRI, an d possibly CT scan s, are usually sufficien t to distin guish th e diagn oses.

Treatment Non operative treatm en t is classically in dicated for growin g ch ildren with kyph osis greater than 45 degrees to 50 degrees. Physical th erapy can be useful to im prove sym ptom s an d reduce ham string tightness but is not capable of im provin g th e deform ity. Bracin g is h elpful on ly in patien ts with som ewh at flexible deform ities an d at least a year of growth rem ain in g. Lon g-term results are best in curves less than 75 degrees and when th e m ore extensive Milwaukee brace is used. Un derarm orth oses, such as th e TLSO, are at a m echanical disadvan tage in m ost cases of Scheuerm an n kyphosis but m ay be utilized for curves with an apex below T9, particularly for disease occurrin g at th e th oracolum bar jun ction .

mann kyphosis demonstrates the kyphotic deformity seen with this disorder. Note the irregularity of the vertebral endplates, Schmorl node formation, and the anterior vertebral wedging. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Th e in dication s for surgical treatm en t of Sch euerm an n kyphosis are n ot well defined. Generally, surgery can be considered for patients with kyphosis greater than 75 degrees, persistent pain recalcitrant to n on operative treatm en t, an d certain ly for any cases with n eurologic impairm en t. Un like scoliosis, th e effect of severe kyph osis on pulm on ary fun ction is m ild: in m ost cases, pulm on ary function tests are either norm al or even increased. As a result, th e decision for surgery sh ould be m ade on an in dividual basis for th ose adolescen ts wh o h ave failed bracin g an d wh o h ave a sufficien tly objection able cosm etic appearan ce as perceived by th e patien t, th e paren t, an d the surgeon . Surgical treatm en t consists of posterior spinal fusion with instrum entation (Fig. 11.222). An terior release of th e th icken ed an d sh orten ed an terior lon gitudin al ligam en t (eith er open or th oracoscopic) is classically in dicated for curves that do n ot correct to less than 50 degrees on forced hyperexten sion lateral radiograph s. However, th e adven t of m odern segm en tal in strum en tation with pedicle screws com bined with m ultiple posterior osteotom ies h as reduced the need for anterior surgery. It is important when un dertakin g surgery to select th e appropriate fusion levels in cludin g an appreciation of th e upperm ost kyph otic segm en t an d extendin g the fusion distally, not only to the

380


A

B

Figure 11.222 (A, B) Posteroanterior (PA) and lateral radio-

graphs of a 17-year-old boy with symptomatic Scheuermann kyphosis and 80 degrees of sagittal plane deformity. (C, D) PA and lateral radiographs 1 year after posterior spinal instrumentation and fusion. (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, CA.)

C

D

lowest in volved level but also to an d across th e first lordotic disk space. Th is m ay require exten din g th e fusion down as low as L2 or L3 but is n ecessary to reduce th e risk of jun ction al kyph osis.

sic triad of Klippel–Feil syndrom e has consisted of a short n eck, low posterior h airlin e, an d m arked lim itation of m otion of th e neck. Most surgeon s now consider any case of con gen ital fusion of cervical vertebrae to con stitute an example of Klippel–Feil syn drom e an d to suggest th at th e patien t is at risk for associated an om alies (Fig. 11.223). Th e etiology of Klippel–Feil syndrom e contin ues to be disputed. Th eories in clude prim ary vascular disruption , fetal in sult, prim ary n eural tube abn orm ality, an d a prim ary gen etic etiology. Th e in ciden ce of th is con dition h as n ever been determ in ed, but reason able estim ates vary from 0.2 to 7 per 1000.

CERVICAL SPINE DISORDERS Klippel–Feil Syndrome In 1912, Klippel and Feil described m assive congen ital fusion of th e cervical spin e in a 46-year-old tailor with m ultiple associated an om alies. Since then , th e clas-

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A

B Figure 11.223 A 3-year-old boy with Klippel–Feil syndrome. (A) Note the short neck and low

posterior hair line. (B) The lateral cervical spine radiograph demonstrates complete fusion of the posterior elements of C2–C3, with reduced disc height anteriorly. Note the reduced space between C3 and C4, which most likely represents a cartilage fusion between C3 and C4 that will probably progress to an osseous fusion later in life. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Probably th e m ost im portan t aspect of th e Klippel– Feil syndrom e is its association with other syndrom es an d anom alies. Congenital cervical fusion has been reported in fetal alcohol syndrom e, as well as in Goldenhar syndrom e. Th e m ost com m on associated m usculoskeletal an om aly is scoliosis, which is m ost often con genital. Sprengel deform ity, cervical ribs, thoracic outlet syndrom e, and torticollis are also seen. The m ost com m on associated craniofacial an om aly is h earin g loss, reported in 15% to 36% of patien ts. CNS an om alies in clude syn kin esis (in volun tary paired m ovem en t of th e h an ds an d arm s), syrin gomyelia, and diastem atomyelia. An increased incidence of congenital cervical spinal stenosis is a well-known phenom en on; th is m ay be com plicated by th e developm en t of in stability adjacent to th e congenital fusion, which is also com m on in Klippel–Feil syndrom e. GU anom alies are present in 25% to 35% of patients. Distribution is sim ilar to that of con gen ital scoliosis, an d th e m ost com m on an om aly is un ilateral ren al agen esis. As with con gen ital spin e deform ity, routine screening of the GU tract with ultrasoun d has been recom m ended for patien ts with Klippel–Feil syndrom e. Con gen ital cervical spin e fusion is, in m any in dividuals, asymptom atic. On the other hand, progressive in stability m ay develop secon dary to abnorm al stresses on m otion segm en ts above or below the areas of congenital fusion . Th is in stability, particularly in in dividual with preexistin g

sten osis, m ay lead to clinically significant spinal cord or n erve root compression . Th ree fusion pattern s h ave been defin ed th at m ay iden tify patien ts with Klippel–Feil syn drom e wh o are at particular risk for n eurologic in jury. Th ese in clude two sets of adjacen t block vertebrae with on e or two in terven in g open disk spaces, occipitalization of th e atlas with a con gen ital fusion below C2, creatin g a risk for C1 –C2 in stability, an d con gen ital fusion with associated cervical stenosis. Th e literature generally advocates a con servative approach for asym ptom atic patien ts with m in im al in stability. Patients with any evidence of myelopathy or significant instability warrant surgical stabilization to m inim ize the risk of a catastroph ic n eurologic in jury.

Os Odontoideum Os odontoideum is an anom aly of th e cervical spine in wh ich th e n orm al odon toid process is replaced by an ossicle with sm ooth circum feren tial cortical m argin s th at h as n o osseous con tin uity with th e body of th e axis. Th e etiology h as been debated; m any believe th at os odon toideum results from un recogn ized traum a th at leads to n on un ion of th e fractured den s. O th ers believe th at os odon toideum h as a con genital origin . On radiographic evaluation, the os is typically seen as a hypoplastic, sclerotic ossicle th at m ay be an terior to, at, or

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Figure 11.224 Lateral cervical spine radiograph demonstrating

an ossicle with well-circumscribed cortical margins and open posterior ring of C1. (Reproduced with permission from Sankar WN, Wills BP, Dormans JP, et al. Os odontoideum revisited: the case for a multifactorial etiology. Spine. 2006;31:979–984.)

posterior to th e typical location of th e den s (Fig. 11.224). CT scan s m ay be n ecessary to adequately visualize th e ossicle. Flexion/ extension views of the cervical spine are importan t to ch eck for atlan toaxial in stability. In ch ildren with neurologic changes or if there is any suspicion for associated spin al cord an om alies, an MRI is warran ted. O s odon toideum h as been reported to cause n eurologic comprom ise and even sudden death. Any patient with a history of n eurologic im pairm ent or n eurologic symptom s sh ould undergo surgical stabilization. A m ore controversial issue is the appropriate treatm ent for the asym ptom atic ch ild with os odon toideum . Gen erally, surgical treatm en t is in dicated in cases of docum en ted in stability (> 4 m m of m otion at C1 –2 on flexion / exten sion views). In th e absen ce of instability, the child m ay be followed with serial dyn am ic radiograph s; any eviden ce of in creasin g m otion , pain , or n eurologic sequelae warran ts surgery.

Atlantoaxial Rotatory Displacement Atlan toaxial rotatory displacem ent m ay be seen followin g m in or traum a, an upper respiratory in fection , or h ead an d n eck surgery. An acute torticollis is seen with a classic “cocked robin’’appearan ce, in which th e head is rotated in on e direction but tilted toward th e oth er direction . Neck discom fort is usually presen t, but in n on traum atic cases, neurologic involvem ent is rare.

Th e diagn osis of fixed rotatory displacem en t of C1 on C2 is m ade radiographically. Plain lateral radiographs can be used to assess for an terior subluxation of th e atlas on th e axis, wh ich m ay be absen t, m ild, or m arked. Subtle m alalignm ent of the head or the posterior arch of C1 m ay also be seen. The m ost definitive test is dynam ic CT scann ing. Axial cuts th rough the C1 –C2 complex with th e h ead rotated 45 degrees to th e righ t an d 45 degrees to th e left will iden tify failure of th e atlas to rotate n orm ally aroun d th e axis, even wh en th e h ead appears to be turn ed (Fig. 11.225). Th is fin din g is diagn ostic of atlan toaxial rotatory displacem en t, or fixed rotatory subluxation as it is som etim es called. Treatm en t of rotatory subluxation depen ds on th e duration of symptom s and th e presence of C1 –C2 subluxation. In dividuals with less th an 1 week of symptom s are usually treated with a soft cervical collar, oral m uscle relaxants, and rest. In patients who fail to respond or in whom symptom s h ave persisted for m ore than 1 week, hospitalization with th e use of cervical h alter traction is in dicated. Wh en sym ptom s h ave been present for m ore than 1 m on th , halo traction can be used, although there is a relatively high risk of redisplacem en t even after reduction . Surgery is warran ted for atlan toaxial rotatory displacem ent that has persisted for m ore than 3 m onths, that h as recurred followin g adequate reduction , or in patients with n eurologic ch an ges. C1 –C2 arth rodesis is perform ed with h alo im m obilization . Residual deform ity usually resolves spontan eously over tim e in the presence of a solid fusion.

Congenital Muscular Torticollis Although strictly speaking it is not a disorder of the cervical spine, congenital m uscular torticollis (CMT) is a com m on cause of n eck deform ity, especially in young children. CMT is a painless deform ity that results from contracture of the sternocleidom astoid m uscle and is the m ost com m on cause of torticollis in newborn s. The etiology rem ain s controversial but is m ost likely from intrauterine or perinatal compartm ent syndrom e that causes fibrosis of the sternocleidom astoid m uscle. Risk factors in clude breech position and difficult delivery; associated conditions include DDH an d m etatarsus adductus. Th e clin ical appearan ce is ch aracteristic with th e ch ild’s h ead tilted toward the in volved m uscle an d th e ch in rotated toward th e con tralateral sh oulder (Fig. 11.226). A m ass (often liken ed to an olive) can som etim es be felt in th e body of th e stern ocleidom astoid durin g th e first 3 m on th s of life. Th is m ass often disappears durin g early in fan cy but is replaced with a tight fibrous band over the len gth of the stern ocleidom astoid as th e m uscle fibroses. In itial treatm en t con sists of a stretch in g program wh ich is successful in the m ajority of cases if started in th e first 6 m on th s of life. In fan ts th at do n ot h ave a palpably tigh t stern ocleidom astoid m uscle or those that do not respond


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B

Figure 11.225 Radiographic findings in atlantoaxial

C

rotatory subluxation. (A) The lateral cervical spinal radiograph demonstrating that the posterior arches fail to superimpose because of the head tilt (arrow). (B) Dynamic computed tomography scans in a 9-year-old girl with a fixed atlantoaxial rotatory displacement, with the head maximally rotated to the left. (C) Her head maximally rotated to the right, in this case, does not reach the midline. The ring of C1 is still in the exact relation to the odontoid as in B, indicating a fixed displacement. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

to m onths of diligent physical th erapy sh ould be im aged with plain radiograph s or if n eeded CT to rule out a con gen ital cervical spin e an om aly. Ch ildren wh o presen t at an older age an d th ose patien ts with torticollis refractory to th erapy m ay occasion ally require surgery. O ption s in clude un ipolar or bipolar release of th e stern ocleidom astoid, resection of th e m uscle, an d Z-plasty len gth en in g.

Down Syndrome

Figure 11.226 Clinical photograph of a young girl with left-

sided congenital muscular torticollis. Note the tight left sternocleidomastoid muscle. (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, CA.)

Upper cervical in volvem ent in Down syndrom e (trisomy 21) h as been reported in an alarm in gly h igh proportion of affected children and adults. Both occipitocervical and atlantoaxial instability have been reported, with estim ates as h igh as 60% and 20%, respectively. An in creased in cidence of cervical spin e an om alies, such as os odon toideum , h as been reported in in dividuals with Down syn drom e an d C1 –C2 instability. Th e n atural h istory of atlan toaxial in stability in Down syn drom e h as n ot been clearly defin ed. There is a tendency toward gradual progression in som e individuals, and it has

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been reported th at progressive in stability an d n eurologic impairm en t is m ore likely in m ale patien ts an d after th e age of 10 years. Most in dividuals are asymptom atic, h owever, an d screen in g radiograph s taken for th e Special O lympics lead in m ost cases to diagn osis, evaluation , an d question s about appropriate treatm en t. Because m ost children with Down syndrom e and C1 –C2 in stability are asymptom atic, th e appropriate role for surgical treatm ent is un clear. An exceedingly high complication rate, including non union, in fection, neurologic worsening, an d even death , h as been reported with C1 –C2 fusion in these patients, and there is on ly anecdotal evidence that atlan toaxial in stability is associated with n eurologic catastroph e. Because of th e h igh complication rate, m ost surgeon s favor a fairly con servative approach . For ch ildren with C1 –C2 instability and m ore th an 4 to 5 m m of m otion , restriction from h igh -risk sports such as gym n astics, divin g, an d soccer is recom m en ded. Surgery can be con sidered for asymptom atic individuals with atlantoaxial instability of 10 m m or m ore. The only definite indication for surgery is a child with a clear-cut history of neurologic impairm en t or eviden ce of myelopathy on physical exam ination along with docum ented atlantoaxial instability. Th e significance and treatm en t of occipitocervical instability is even less clearly defin ed.

SPONDYLOLYSIS AND SPONDYLOLISTHESIS Spon dylolysis is a stress fracture of th e pars in terarticularis of th e lum bar spin e. Spon dylolisth esis refers to th e forward slippage of on e vertebra on another. The overall inciden ce in adolescen ts is 5% to 6% by th e en d of skeletal growth . Male patien ts are m ore com m on ly affected th an fem ale patien ts, by a 6:1 ratio.

Pathophysiology and Classification Spon dylolysis is a stress fracture th at is th ough t to result from repetitive hyperextension stresses in gen etically predisposed in dividuals. Spon dylolysis is m ore com m on in ath letes wh o in cur repetitive hyperexten sion forces in the lower lum bar spine such as gym nasts or interior linem en in football. In som e cases, spon dylolysis can progress to a spon dylolisth esis. Spon dylolisth esis refers to th e forward slippage of one vertebra on another (Fig. 11.227). Wiltse an d oth ers h ave classified spon dylolisth esis in to six types based on etiology. In ch ildren , class I (con gen ital) an d II (isth m ic) are m ost com m on . Con gen ital or dysplastic spon dylolisth esis is th e result of a con gen ital defect at the L5 –S1 articulation . Typically, th e defect con sists of hypoplastic facets or abn orm al facet orien tation th at allows the superior vertebral body to slip over the inferior vertebral body. Th e pars in terarticularis m ay be dysm orph ic but

Figure 11.227 An 18-year-old girl with high-grade spondylolis-

thesis. Note the anterior translation of L5 relative to the body of S1.

is intact. Progression is com m on in this type of spondylolisthesis. Class II, or isthm ic, spondylolisthesis is the m ost com m on type seen in ch ildren . In this case, the spondylolisthesis occurs because of a defect in th e pars in terarticularis (spon dylolysis). Approxim ately 80% to 90% of cases involve the L5 –S1 level, with 5% to 15% affectin g L4 –L5. Th e rem ain in g types of spon dylolisth esis (wh ich rarely affect children ) include degenerative, traum atic, pathologic, an d postoperative. Progression of spondylolisthesis has been associated with th e adolescen t growth spurt, lum bosacral kyph osis, an d greater degree of in itial slip on presentation .

Presentation Spon dylolysis an d spon dylolisth esis are som e of th e m ost com m on causes of back pain in the pediatric population, an d patients present typically with pain in the low back, occasion ally radiatin g in to th e buttocks or posterior th igh . Th is back pain is largely m ech an ical an d is worsen ed by activity an d improved by rest. In advanced cases of spondylolisthesis, an terior translation of the superior vertebral body can result in foram in al sten osis of th e exitin g n erve root an d can presen t as radiculopathy.


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Physical Examination In spon dylolysis, th e pain is usually aggravated by hyperexten sion an d rotation . Tigh t h am strin gs (as eviden ced by an increased popliteal angle) are com m on. High-grade slips can also result in the typical appearance of lum bar hyperlordosis (balancin g the lum bosacral kyphosis), crouch ed posture, an d waddlin g gait.

Radiographs A num ber of radiographic findings have been described in spon dylolysis and spondylolisthesis. Most defects of the pars in terarticularis can be seen on spot lateral radiograph s of th e lum bosacral spin e. In som e cases, furth er defin ition of th e defect can be seen on oblique radiograph s, wh ere the characteristic “collar’’on the neck of the “Scotty dog’’is seen (Fig. 11.228). Lateral radiograph s also allow gradin g of spon dylolisth esis. Th e two m ost im portan t radiograph ic m easures are the percent slip (Meyerdin g classification ) an d the slip angle. Th e Meyerding classification is based on the percen tage of translation of th e superior vertebral body across the inferior vertebral body. Th e superior endplate of the inferior vertebrae is divided into quadran ts, an d the am ount of translation is graded between I and IV. Grade V or tran slation over 100% is term ed spondyloptosis (Fig. 11.229). Th e slip angle quan tifies the am ount of kyphosis

Figure 11.229 Meyerding system for grading spondylolisthesis. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

th at results from th e L5 vertebral body slidin g forward over th e sacrum . Th e slip an gle is m easured by drawin g a lin e perpen dicular to a lin e drawn alon g th e posterior aspect of th e vertebral body an d m easurin g th e an gle between th at an d a lin e parallel to th e in ferior en dplate of L5 (Fig. 11.230). Slip an gles greater th an 35 degrees to 40 degrees are at risk for progression .

Slip angle

Figure 11.228 Oblique radiograph demonstrating spondylol-

ysis (white arrows) at L3 and L5. The location of the stress fracture is the neck of the “Scotty dog.” (Reproduced with permission from Weinstein SL. The Pediatric Spine. Philadelphia, PA: Lippincott Williams & Wilkins, 2001.)

Figure 11.230 Slip angle helps quantify the amount of local

kyphosis. (From Wiesel SW, Delahay JN. Essentials of Orthopaedic Surgery. 2nd ed. Philadelphia, PA: WB Saunders, 1997.)

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Special Tests In certain cases of spon dylolysis, plain radiograph s (in cludin g obliques) are non diagnostic. Bone scan s can show in creased uptake in patien ts with n ew spon dylolytic lesion s but m ay be cold in those who h ave had lon g-term symptom s. CT scans are m ore sensitive th an either plain radiographs or bone scans and allow for m ultiplanar recon struction s. Single-ph oton em ission CT (SPECT) scans h ave greater sen sitivity an d specificity for diagn osin g spon dylolysis compared with radiograph s an d bon e scan s. MRI is useful for rulin g out oth er causes of back pain an d for evaluatin g sten osis as part of preoperative plan n in g.

Differential Diagnosis Th e differen tial diagn osis for spon dylolysis an d spon dylolisth esis is sim ilar to th at of back pain (see later). Neoplasm s, m uscular strain s, in fection s, an d psych osom atic back pain can all presen t sim ilar to spon dylolysis/ spondylolisth esis. Usually, radiograph s or advan ced im agin g tech n iques are diagn ostic.

Treatment Many cases of spon dylolysis are foun d in ciden tally, are asymptom atic, an d require n o treatm en t. In patien ts wh o presen t with symptom atic spon dylolysis, th e m ain stay of treatm en t is n on surgical. Usually th is in volves activity restriction, nonsteroidal an ti-inflam m atory drugs (NSAIDs), an d physical th erapy focusin g on core stren gth en in g an d ham string stretching. In patients suffering from acute spondylolysis, bracing can be useful. It is im portant to note that the resolution of symptom s does not necessarily correlate with h ealin g of th e pars defect. Th e goal of treatm en t is pain resolution an d return to full activity; as a result, patien ts sh ould be m an aged on th e basis of th eir clinical response, n ot the radiographic findings. Patients with spondylolysis wh o are still sym ptom atic after conservative treatm en t m ay be can didates for direct repair of the pars defect. Various tech n iques h ave been described in cludin g wirin g, screw fixation , an d screw h ook con structs usually with autogen ous bon e graftin g. In patien ts with disk degen eration or any degree of segm en tal in stability, posterolateral fusion with or with out in strum en tation is th e treatm en t of ch oice. Treatm en t of spon dylolisth esis depen ds on th e grade of the slip and the presence or absence of symptom s. Asymptom atic patien ts with grade I spon dylolisth esis are typically treated with observation alon e with out activity restriction ; routin e radiograph ic follow-up is recom m en ded on an an nual basis to m onitor for slip progression. Asymptom atic patien ts with h igh er grades of spon dylolisth esis are usually restricted from h igh -risk activities such as gym n astics or con tact sports. Symptom atic patien ts with grade I or

II spon dylolisth esis are treated con servatively in a sim ilar m anner as for patients with spondylolysis. The role of prophylactic fusion in h igh er-grade but asymptom atic spon dylolisthesis is som ewhat controversial. Because of the risk of furth er progression an d th e developm en t of sign ifican t back pain in adulth ood, m ost surgeon s recom m en d fusion in an asymptom atic ch ild or adolescent if the percent slip is greater th an 50% (grade III or m ore). Harris an d Wein stein , h owever, h ave reported a series of adults with h igh-grade spon dylolisth esis treated nonoperatively and compared th em with in dividuals wh o h ad un dergon e fusion . Alth ough pain was n ot un com m on , th ere was a relatively h igh level of function in in dividuals with grades III and IV spon dylolisth esis wh o h ad not undergone surgery, suggesting th at observation m ay be reasonable in these patients, particularly if th ey are followed closely for progression . In gen eral, surgery is in dicated for patien ts wh o h ave persisten t back pain despite 6 to 12 m onths of aggressive nonoperative treatm en t (regardless of grade) an d for m ost patients with spondylolisthesis greater than 50%. Arthrodesis is usually perform ed with the m ost com m on approach in the pediatric population being posterior fusion (Fig. 11.231). In h igh er-grade slips, th e fusion is usually exten ded to L4 an d an an terior fusion m ay be used with or with out dowel graftin g or in terbody structural support. Non in strum en ted procedures are effective in reducin g symptom s but h ave a lower fusion rate th an do instrum ented techniques. Historically, patients were im m obilized in a spica cast after noninstrum en ted fusion; h owever, som e surgeon s use a TLSO with a th igh extension durin g th e postoperative period. Most surgeons now prefer posterior segm en tal in strum en tation an d fusion for patien ts with spon dylolisth esis. As m en tion ed, in strum en tation in creases fusion rates an d also allows correction of th e slip an gle, wh ich can im prove body posture an d m echanics. Another advantage of instrum en tation is that it allows for full neural decompression, which is vital in cases of foram in al sten osis. Reduction of high-grade spon dylolisthesis is con troversial. Patients with high -grade disease have sign ificant cosm etic deform ity and abn orm al body m ech anics. In addition, high-grade spondylolisthesis creates an environm ent in which the fusion m ass (even if extended up to L4) is under ten sion an d is th erefore at sign ifican t risk for n on un ion , ben din g, an d con tin ued progression . For th ese th eoretical reason s, reduction h as its advan tages. Tech n iques in clude traction and casting, com bined anterior and posterior approach es, posterior in strum en tation an d reduction , an d circum feren tial L5 body resection with reduction . Alth ough success h as been reported for all these techn iques, reduction of high-grade spondylolisth esis has a significant risk of com plication s in cludin g loss of fixation , loss of correction, an d, m ost importantly, a worrisom e rate of neurologic deficits (up to 20% –30% in som e series). As a result, m any surgeons prefer in situ fusion.


A

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B

C

D Figure 11.231 (A, B) This 11-year-old girl underwent posterior decompression and instrumented posterolateral fusion from L5 to sacrum, using autogenous iliac crest graft laterally. (C) At 5 years 6 months postoperatively, she had an excellent arthrodesis on the posteroanterior view. (D) The lateral view shows stability at L5–S1. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

BACK PAIN Back pain in adults is so com m on th at it is alm ost a norm al variant. Although bothersom e and at tim es incapacitating, m ost patients and fam ily m em bers accept the fact that a backach e is a routin e occurren ce, frequen tly difficult to diagnose, an d often resistant to treatm ent. When significant back pain occurs in ch ildren , h owever, a certain an xiety level is seen on the part of fam ily m em bers and referring physician s. Most of th is con cern stem s from th e fact th at

back pain h as tradition ally been con sidered a rare fin din g in th e pediatric population . In reality, back pain is relatively com m on in adolescen ts an d ch ildren . Recen t studies in dicate th at m ore th an 50% of ch ildren will experien ce back pain by age 15 an d rough ly 24% of adolescen t girls complain of back pain m ore th an once a week. It is un clear wh at h as caused th is apparent increase in incidence, although sedentary lifestyles, in creased sports participation, an d backpack use h ave all been th ough t to play a role. Pediatric back pain can be caused by a variety of con dition s

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som e of which require prompt treatm ent. As a result, an organ ized approach with a th orough h istory, physical exam in ation , an d appropriate diagn ostic studies is n ecessary when evaluating back pain. Adiagnosis of m echan ical back pain sh ould be con sidered on ly after oth er m ore serious path ologies h ave been ruled out.

Presentation A careful detailed history should be obtain ed from both the child and the parent. The age of the patient at presentation is im portan t in th e evaluation of low back pain . Th e prevalen ce of back pain in ch ildren youn ger th an 10 years is less com m on th an in adolescen ts an d is m ore likely to have an organic etiology such as an in fection or a tum or. Th e on set of symptom s sh ould be explored, in cludin g any in citin g traum a, as well as th e location of th e pain an d sites of radiation . Pain at rest is con cern in g an d is classically associated with neoplasm s. The severity of pain is often best assessed by askin g about th e ch ild’s ability to participate in sports an d oth er recreation al activities. It is n ot at all un com m on for adolescen ts to com plain of relatively m ild back pain with n o specific cause; th is is particularly true if the diagnosis of scoliosis has recen tly been m ade. On the oth er h an d, pain th at is of sufficien t m agn itude to in terfere with activities such as attendin g school or participatin g in organ ized sports is m ore worrisom e. Patien ts sh ould be question ed about n eurologic sym ptom s such as radiculopathy or paresth esias in th e legs an d recen t ch an ges in bowel or bladder h abits. An in quiry sh ould be m ade about the child’s general m edical status, including a thorough review of system s an d specific question in g about con stitution al symptom s (e.g., fever, ch ills). Fin ally, it is im portan t to rem em ber th at psych ological factors can play a role in back pain , especially in teen agers. It is th erefore im portan t to assess th e social h istory for fam ily dysfun ction an d oth er sources of psychological stress.

Physical Examination Physical exam in ation is perform ed with th e patien t in an exam in in g gown , disrobed down to un derwear with sh oes an d socks rem oved. Skin sh ould be assessed for café au lait spots, dimples, or h airy patch es. Balan ce an d posture sh ould be evaluated in the standin g position to determ ine thoracic kyphosis, lum bar lordosis, and overall alignm en t. Gait sh ould be evaluated for eviden ce of weakn ess or pain . Flexibility can be assessed by exam in in g forward ben din g, rotation , an d exten sion —pain with th e latter can be suggestive of spon dylolysis. Th e spin ous processes an d paraspin al m uscles sh ould be palpated to determ in e th e location of the pain. Back pain that is well localized (positive “finger test’’in wh ich th e patien t poin ts to on e particular spot as th e source of pain) over bone is particularly indicative for un derlyin g path ology, wh ereas pain over a broad distribution is likely to be stan dard m ech an ical back pain . In traabdom -

inal and retroperitoneal pathology can be ruled out with a careful abdom in al exam in ation . Th e straigh t leg raisin g test can h elp diagn ose radiculopathy, an d th e popliteal an gle sh ould be m easured to determ ine the degree of ham string tightness. Th e presence of a cavus foot or claw toes, particularly unilateral, is suggestive of in traspinal pathology. Finally, a thorough neurologic exam ination is m andatory includin g an assessm en t of m otor stren gth, sensation, and deep ten don reflexes.

Radiographs Adolescen ts with m echanical back pain (without any red flags in the history an d physical exam ination) often do n ot require radiographic evaluation . Sym ptom atic treatm en t including rest, physical therapy, and judicious use of NSAIDs is usually sufficien t, but follow-up exam in ation s are important to ensure improvem ent with these m easures. Ch ildren youn ger than 10 years and any patients with persisten t sym ptom s, n ight pain , or constitutional complaints sh ould be im aged at th e in itial visit. Plain AP and lateral radiograph s of th e spin e sh ould be obtain ed, an d dyn am ic film s are h elpful if in stability is suspected. O blique film s of th e lum bosacral spin e can be obtain ed if spon dylolysis is being considered but are not routin ely ordered. Standing views of the full spine are utilized for cases of spin al deform ity.

Special Tests Bon e scan s are a sen sitive but relatively n on specific m odality that will iden tify m ost spin al colum n and pelvic conditions such as tum ors, infections, an d spondylolysis. The sensitivity and specificity can be enh anced with SPECT scan n ing, particularly wh en the diagnosis of spondylolysis is an issue. CT scan s are the best im aging m odality for evaluatin g bon ey anatomy, and are extrem ely useful in cases where a bone tum or (such as osteoid osteom a) is suspected (Fig. 11.232). Th e presen ce of n eurologic fin din gs usually warran ts an MRI of th e spin e. MRI is m ore sen sitive and specific in the diagnosis of tum or or infection and is the im aging m odality of choice for disk abnorm alities including h erniation and diskitis. Laboratory testing is occasion ally in dicated in the child or adolescent with back pain an d is m ore com m on ly utilized in th is settin g th an in the adult. Urinalysis and complete blood cell count m ay be obtain ed, an d th e sedim en tation rate an d C-reactive protein level are good screen in g tests for n eoplasm or in fection . Several blood tests are available to complem en t th e search for un derlying rheum atologic disorders, but this testin g is usually deferred to th e rh eum atologist.

Differential Diagnosis and Treatment Multiple diagnoses can result in back pain. Som e clue as to th e un derlyin g n ature of th e con dition m ay be apparen t


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Figure 11.232 A computed tomographic scan of a 13-year-old

boy with back pain demonstrates a nidus consistent with an osteoid osteoma in the posterior elements of the spine. (Reproduced with permission from Weinstein SL. The Pediatric Spine. Philadelphia, PA: Lippincott Williams & Wilkins, 2001.)

based on th e h istory an d physical exam in ation , but it is usually th e radiograph ic workup th at will ultim ately lead to th e diagn osis. Sin ce n eoplasia an d in fection are th e m ost om in ous con dition s associated with back pain , it is im portan t to con sider th ese diagn oses an d rule th em out in a tim ely fash ion before con siderin g m ore m ech an ical or psych osom atic etiologies. Neoplasm s are rare but are a con cern in g cause of back pain in ch ildren an d adolescen ts. Most bon e tum ors are ben ign an d h ave a predilection for th e posterior elem en ts of th e spin e. Th e m ost com m on tum ors of th e posterior elem en ts in clude osteoid osteom a, osteoblastom a, an d an eurysm al bone cyst. Langerhans cell histiocytosis (or eosin oph ilic gran ulom a) usually affects th e an terior colum n an d can lead to vertebral body collapse an d th e ch aracteristic vertebra plana (Fig. 11.233). Malignant bone tum ors such as Ewing sarcom a or osteosarcom a are rare. In younger children, leukem ia can first present as back pain. Neuroblastom a can also be seen in th is age group. In traspinal tum ors m ay m anifest as back pain, and compression of n eural elem en ts can lead to leg sym ptom s, atrophy, or bowel an d bladder dysfun ction . Tum ors are classically associated with night pain and can be associated with a variety of con stitution al complain ts such as fever an d weigh t loss. Plain radiographs m ay reveal lytic or blastic lesions, but furth er workup with a CT or an MRI is usually n ecessary. Biopsy m ay be n ecessary, and treatm ent is depen den t on th e n ature of th e specific lesion . Spin e in fection s in ch ildren are usually due to diskitis or vertebral osteomyelitis, an d th e m ean age of presen tation is 6 years of age. In addition to back pain, patients can complain of abdom inal pain an d lower extrem ity discom fort. Children often refuse to walk, stand, or even sit. Fever is com m on on presen tation an d th e sedim en tation rate an d C-reactive protein level are usually elevated. Radiograph s early in th e disease course m ay be n on diagn ostic;

Figure 11.233 Lateral view of the spine demonstrating com-

plete collapse of the L1 vertebral body (vertebra plana) from Langerhans cell histiocytosis. (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, CA.)

even tually disk space n arrowin g an d en dplate irregularities will develop. Prior to th e appearan ce of th ese radiograph ic changes, a bone scan or MRI m ay be necessary to m ake th e diagn osis (Fig. 11.234). Patien ts with diskitis or osteomyelitis are usually treated empirically with out biopsy because th e predom in an t offen din g organ ism is Staphylococcus aureus. A short course of intravenous antibiotics followed by transition to an oral regim en is a typical treatm ent algorithm . Spin al deform ity can be associated with som e degree of back pain . Th oracolum bar Sch euerm an n kyph osis is a com m on source of pain in adolescen ts an d probably results from m echan ical overuse. Diagnosis is apparen t on lateral radiographs an d treatm en t usually consists of core stren gth en in g, an d occasional use of NSAIDs (see previous section ). Idiopath ic scoliosis is not thought to be a painful con dition but can be associated with m ild com plain ts from tim e to tim e. Generally, advanced im aging is not n ecessary un less th e pain is so severe as to in terfere with sch ool atten dan ce or recreation al activities, a n eurologic abn orm ality is seen, or in th e setting of scoliosis there is rapid curve progression or an atypical curve pattern . Spon dylolysis an d spon dylolisth esis are a com m on cause of back pain in ch ildren an d adolescen ts an d h ave been discussed in a previous section . Diagn osis is usually

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A

B

Figure 11.234 (A) Lateral radiograph of a 4-year-old child with diskitis demonstrating disc space narrowing. (B) A positive bone scan with increased uptake at T11 and T12 confirms inflammatory involvement on both sides of the disc. (Reproduced with permission from Weinstein SL. The Pediatric Spine. Philadelphia, PA: Lippincott Williams & Wilkins, 2001.)

m ade on spot lateral radiograph s of th e lum bosacral spin e. Low-grade disease is m anaged con servatively with core stren gthen ing and occasion al use of NSAIDs; high-grade conditions m ay require surgery. Disk h ern iation is a m uch less com m on en tity in ch ildren th an in adults. Th e straigh t leg raisin g test correlates well with presence of a hern iation , but MRI is the gold standard for m akin g th e diagn osis. O n e should keep in m in d th at MRI can be “overread’’ an d th at m ost fin din gs of bulgin g discs in ch ildren are n ot clin ically relevan t. Th is condition should be distinguish ed from vertebral apophyseal rin g fractures, wh ich do not occur in adults. Patien ts with apophyseal in juries typically present with a sudden on set of pain (with or with out associated radiculopathy) after traum a or liftin g a h eavy object. Male weigh t lifters are m ost com m on ly affected. Th e m ech an ism of in jury is flexion and axial loading of the spinal colum n. Under an axial load, th e disk bulges an d places traction on th e posteroin ferior apophysis. Th is apophysis can avulse an d displace in to th e spin al can al, causin g n eural compression . CT or MRI can be diagn ostic, alth ough both are often needed to con firm th is relatively rare diagnosis, and surgical excision of th e fragm en t m ay be n ecessary for pain relief.

Mech an ical or activity-related back pain is com m on am ong adolescen ts, especially th ose who are active in sports. Most pain is due to soft tissue strains or overuse fatigue. Characteristically, the pain is diffuse, is exacerbated by activity, and is relieved by rest. Radiographs are usually n ot required but sh ould be ordered if oth er con dition s need to be ruled out. It is important to rem em ber th at while the diagn osis of m ech an ical back pain in adolescen ts is com m on, the surgeon m ust not m iss a m ore concern ing underlyin g diagn osis. Any red flags in th e h istory or physical exam in ation sh ould prompt a m ore th orough diagn ostic workup. Th is is particularly true in ch ildren youn ger th an 10 years, in wh om on e can alm ost always fin d a specific diagn osis wh en persisten t back pain is presen t. Most acute soft tissue strain s will resolve over 4 to 6 weeks with appropriate activity m odification s. Overuse back pain is gen erally treated by avoiding the offendin g activity, physical therapy focusing on stretching, core strengthen ing and aerobic condition in g, an d appropriate use of NSAIDs. Patien ts wh o h ave persistent sym ptom s in spite of con servative m an agem ent should undergo furth er diagnostic im aging. In a sign ifican t n um ber of patien ts, n o discrete etiology m ay be found for back pain in spite of a thorough diagn ostic workup. Several studies have shown th at adolescents


suffering from psychological stress, either from unstable hom e en viron m ents or from peer pressure, can m anifest som atic com plaints such as headach e, fatigue, an d back pain . Th e diagn osis of psych osom atic back pain is on e of exclusion , an d it is essen tial th at all oth er organ ic causes of back pain be ruled out. A m ultidisciplin ary approach con sisting of physicians, psychologists, and th erapists is recom m en ded wh en treatin g th is subgroup of patien ts. In gen eral, treatm en t sh ould focus on m en tal coun selin g an d physical con dition in g an d sh ould avoid th e use of m uscle relaxan ts an d opioids.

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tran sported on pediatric spin e boards th at h ave recesses for the h ead or that elevate the body in relation to the head. Ch ildren also h ave in creased ligam en tous laxity in th eir n ecks an d m ore h orizontally sh aped facet join ts, both of wh ich put th em at in creased risk for cervical spin e instability. Fin ally, th e pediatric spin al colum n h as in creased elasticity compared with th at in adults; as a result, spin al cord in jury with out radiograph ic abn orm ality (SCIWO RA) can occur.

Physical Examination

Motor vehicle accidents are the m ost com m on m echanism of spin al in jury in ch ildren . O th er m ech an ism s vary by th e age of the patien t. In newborn s, birth traum a or child abuse sh ould be considered as an etiology. In sch ool-aged ch ildren , spin e in juries often result from falls; in adolescen ts, athletic traum a is m ore com m on.

Because ch ildren are often difficult to exam in e, all ch ildren with poten tial traum a to th e spin e sh ould be treated as a spin al injury un til proven otherwise. In patients sustain ing h igh -en ergy traum a, in itial evaluation con sists of ensurin g th e stan dard ABCs of airway, breath in g, an d circulation . After com pletion of th e prim ary survey an d stabilization of th e patien t, th e secon dary survey is con ducted sim ilar to stan dard adult traum a protocols. As m entioned, patients sh ould be im m obilized and tran sported using m odified spin e boards. After initial stabilization, all children with suspected spin e in juries sh ould undergo a careful n eurologic exam ination. Strength, sensation, and deep tendon reflexes in both th e upper an d lower extrem ities sh ould be evaluated. A rectal exam in ation m ay be in dicated.

Unique Factors in Pediatric Spine Injuries

Radiographs

Several factors m ake pediatric spin e in juries un ique com pared with th ose in adults. Th e h ead of a ch ild is proportionately larger than that of an adult. In addition, children have weaker paraspin al m uscles to provide head con trol. Th e result is an in creased relative risk of cervical spin e in jury in children. Because of their larger head-to-body ratio, im m obilization on a standard adult spin e board will flex the neck an d could exacerbate any cervical spine injury (Fig. 11.235). Children should therefore be im m obilized and

In itial evaluation sh ould con sist of stan dard AP an d lateral radiograph s of th e in volved area. If an in jury is iden tified, radiographs should be perform ed of the entire spin e to rule out a noncontiguous in jury. It is importan t to be aware th at several radiograph ic fin din gs in th e im m ature spin e can be m isin terpreted as pathologic when in fact they are norm al. As in other parts of the body, pediatric spine bon es can be in completely ossified an d growth cen ters can be m istaken for fractures. For exam ple, in th e youn g ch ild,

SPINE TRAUMA Spin e fractures con stitute approxim ately 1% of all pediatric fractures. The cervical spine is the m ost typical location of injury, accounting for 60% of all pediatric spinal injuries.

Mechanisms of Injury

A

Figure 11.235 (A) Adult immobilized on a standard

backboard. (B) Young child on a standard backboard. The relatively large head flexes the neck and forces the cervical spine into a kyphotic position. (Reproduced with permission from Beaty JH, Kasser JR. Rockwood and Wilkins’ Fractures in Children. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

B

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B

A Figure 11.236 (A) Pseduosubluxation of C2 on C3. In flexion, the posterior element of C2 should

normally align itself with the posterior elements of C1 and C3. The relationship of the body of C2 with the body of C3 gives the appearance of subluxation; however, the alignment of the posterior elements of C1–C3 confirms pseudosubluxation. (B) True subluxation. (Reproduced with permission from Beaty JH, Kasser JR. Rockwood and Wilkins’ Fractures in Children. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

cervical vertebral bodies often appear wedged with deficient an terosuperior m argins. The atlan todens interval is often in creased compared with adults because of th e presen ce of cartilage aroun d th e im m ature odon toid process; gen erally, an in terval less th an 5 m m is con sidered n orm al in a ch ild. Perh aps th e m ost com m on m istake is diagnosing pseudosubluxation as true cervical spine in stability. Pseudosubluxation is th e apparen t an terior displacem en t of C2 on C3 (or less com m on ly C3 on C4), wh ich occurs in 9% of children (Fig. 11.236). It is believed to be facilitated by th e m ore h orizon tal orien tation of th e upper cervical facet join ts, wh ich becom e m ore vertical as the child ages; as a result, pseudosubluxation is rarely seen after th e age of 8 years. Pseudosubluxation can be distin guish ed from true cervical in jury by th e absen ce of a h istory of sufficien t traum a to explain th e in jury, by spon tan eous reduction of C2 on C3 wh en th e h ead is exten ded, an d by alignm ent of the spin olam in ar line (Swischuk’s line) (Fig. 11.237).

Treatment Th e m ajority of pediatric spin e fractures are stable an d can be treated with sim ple im m obilization (cervical collar or TLSO). Displaced cervical spin e fractures th at require reduction an d upper cervical spin e in stability m ay n ecessitate

Special Tests CT scan s are extrem ely useful in pediatric spin e traum a. In patien ts wh o h ave in adequate radiograph s or in wh om the diagnosis is uncertain, CT is an excellent screening tool with a high sensitivity for boney in jury. In addition , CT is the diagnostic m odality of ch oice to visualize the upper cervical spine including the occipitocervical junction. MRI is in dicated for cases of suspected soft tissue in jury such as ligam en tous tears or h ern iated disks. MRI is also th e best test for evaluatin g spin al cord in jury.

Figure 11.237 The spinolaminar line (Swischuk’s line) should remain aligned in the presence of pseudosubluxation of C2 on C3. (Reproduced with permission from Beaty JH, Kasser JR. Rockwood and Wilkins’ Fractures in Children. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)


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m in im ize th e ch an ce of skull pen etration . Sim ilar to adults, the halo ring should be positioned below the equator of the head, approxim ately 1 cm above the ears an d eyebrows. Anterior pins should be placed above th e lateral half of the orbit to avoid in jury to th e supraorbital an d supratroch lear n erves. In ch ildren youn ger th an 1 year, Min erva casts can be used to im m obilize th e spin e.

SPECIFIC PEDIATRIC SPINE INJURIES Occipitocervical Injuries B

A

Figure 11.238 (A) Custom halo vest and superstructure.

(B) In the multiple pin, low-torque technique, 10 pins can be used for an infant halo attachment. Usually four pins are placed anteriorly, avoiding the temporal region, and the remaining six pins are placed in the occipital area. (Reproduced with permission from Beaty JH, Kasser JR. Rockwood and Wilkins’ Fractures in Children. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

halo im m obilization with or without cervical fusion . Use of h alo is well accepted for pediatric patien ts older th an 1 year. Because ch ildren h ave th in n er skulls, application tech n iques are sligh tly differen t th an for adults. In ch ildren youn ger th an 8 years, m ultiple pin s (often as m any as 8 –12) sh ould be placed at lower torque. Usually, four pin s are placed anteriorly with the rem ain ing pins in the occiput (Fig. 11.238). Unlike adult pins that are routinely tightened to 8 in ch -poun ds, pin s in youn g ch ildren sh ould be “fin gertight’’ (approxim ately 2 –4 inch-pounds). Retightening of pin s after th e in itial application is n ot recom m en ded to

Occipitocervical dissociations are purely ligam entous injuries an d are associated with an extrem ely h igh m ortality rate (Fig. 11.239). Injuries can be classified as anterior, vertical, or posterior on th e basis of the displacem ent of th e occiput in relation to th e cervical spin e. Early diagn osis an d treatm ent are critical because patients are at a h igh risk for n eurologic in jury or sudden death . If radiograph s are nondiagnostic, an urgent MRI is warran ted. Reduction sh ould be perform ed under fluoroscopic guidan ce; traction should be avoided as it can exacerbate axial displacem ent. Patients can be temporarily im m obilized in a halo vest, but defin itive treatm ent con sists of occipitocervical fusion with instrum entation.

Fractures of C1 Fractures of the atlas ring constitute rough ly 10% of all cervical spine injuries (Fig. 11.240). The m ech anism of in jury is an axial load; neurologic injury is rare because, when fractured, the ring of C1 expands, creating m ore space for th e spin al cord. Posterior arch fractures are stable an d can

A

B Figure 11.239 (A) Lateral radiograph of a patient with atlanto-occipital dislocation. Note the

increase in the facet condylar distance. (B) Lateral radiograph after occipital-C1 arthrodesis. (Reproduced with permission from Beaty JH, Kasser JR. Rockwood and Wilkins’ Fractures in Children. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Posterior arch fracture

Burst fracture

Lateral mass fracture

Figure 11.240 There are three common types of atlas fractures: posterior arch fractures, in which

the lateral masses do not spread; burst or Jefferson fractures, in which the lateral masses will spread and displace laterally; and lateral mass fractures, in which displacement of the lateral mass occurs on the fractures side. (Reproduced with permission from Jackson RS, Banit DM, Rhyne AL, et al. Upper cervical spine injuries. J Am Acad Orthop Surg. 2002;10:271–280.)

A

B

Figure 11.241 (A) Lateral radiograph of trau-

C

matic C1–C2 instability. (B) Note the increase in the atlantodens interval on the dynamic lateral radiograph. (C) Lateral radiograph after C1– C2 arthrodesis. (Reproduced with permission from Beaty JH, Kasser JR. Rockwood and Wilkins’ Fractures in Children. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)


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be treated with collar im m obilization for 10 to 12 weeks. Burst fractures or lateral m ass fractures with m ore th an 6.9 m m of overhang on the open m outh odon toid view im ply in jury to th e tran sverse ligam en t. Because of th e resultan t atlan toaxial in stability, th ese in juries usually require C1 –C2 arthrodesis. Fractures with less than 5 m m of displacem en t can be treated with a h alo vest for 3 m on th s.

Atlantoaxial Injuries Atlantoaxial injuries are alm ost always ligam en tous. Norm ally, the tran sverse ligam ent is the prim ary stabilizer of the C1 –C2 articulation , with additional stability provided by the apical an d alar ligam ents. Rupture of th is ligam entous complex can occur from excessive flexion forces. Lateral flexion / exten sion views of th e cervical spin e are usually diagnostic (Fig. 11.241). In ch ildren, an atlan todens interval m ore than 5 m m is con sidered abnorm al. MRI can also be helpful to delineate the ligam entous injury. Confirm ed cases of in stability sh ould be treated with posterior arthrodesis of C1 –C2.

Odontoid Fractures In ch ildren , a syn ch on drosis, exists at th e base of th e odon toid process, wh ich closes aroun d th e age of 5 years. Th e m ajority of pediatric dens fractures occur through this physeal area due to a flexion m om ent to the cervical spine (Fig. 11.242). Lateral cervical radiographs are usually diagnostic but can be in con clusive in n on displaced in juries. In th ese cases, MRI can be helpful to m ake the definitive diagnosis. Most fractures can be treated by reduction and halo im m obilization for 8 to 12 weeks.

Traumatic spondylolisthesis of C2 (Hangman Fracture) Fractures th rough th e pedicle of C2 are referred to as Hangman fractures an d result from hyperexten sion in juries. Th e diagn osis is usually apparen t on lateral cervical spin e radiograph s, as th ere is often displacem en t at th e fracture site with som e forward subluxation of C2 on C3 (Fig. 11.243). Neurologic injury is rare because (sim ilar to C1 rin g fractures) m ore space is created for th e spin al cord from displacem ent of the fracture. Treatm ent should be symptom atic with im m obilization in a h alo or Minerva cast for approxim ately 8 to 12 weeks. For n onunions and fractures with significant angulation, posterior or anterior arthrodesis of C2 –C3 m ay be in dicated.

Subaxial Cervical Spine Injuries Th e subaxial cervical spin e refers to C3 –C7; injuries in this region are rare in young children an d usually occur in adolescents. Several patterns of injury h ave been de-

Figure 11.242 Lateral radiograph in an almost 3-year-old boy

demonstrates an odontoid fracture through the dentocentral synchondrosis with anterior angulation and translation. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

scribed in th e subaxial cervical spine in cluding ligam entous disruptions, facet dislocations, compression fractures, and burst fractures. Posterior ligam entous disruption s result from flexion or distraction m echanism s (Fig. 11.244). Patien ts usually com plain of posterior ten dern ess at th e site of in jury; often , th e on ly radiograph ic eviden ce of in jury is subtle widening of the spinous processes. MRI can be h elpful to confirm the presen ce of ligam en tous dam age. Patien ts can be in itially m an aged with a cervical orth osis; h owever, any sign of in stability is an in dication for posterior arth rodesis. Sim ilar to oth er subaxial cervical spin e in juries, un ilateral an d bilateral facet dislocation s are m ore com m on in adolescents. Diagnosis is usually apparent on lateral radiograph s. Reduction sh ould be perform ed by traction if possible or open reduction if closed m eth ods are unsuccessful. Either way, defin itive treatm ent consists of posterior arth rodesis. Compression fractures are the m ost com m on subaxial spine fracture in children . The m echanism of injury is flexion an d axial loading. Lateral cervical spin e film s will dem on strate loss of vertebral body h eigh t. Th ese in juries are alm ost always stable and can be treated with a cervical collar for 3 to 6 weeks. Flexion / exten sion radiograph s sh ould be obtain ed 2 to 4 weeks after injury to con firm stability of th e cervical spine. Burst fractures are caused by an axial load. Although radiograph s are usually sufficien t to m ake th e diagn osis, CT scan s are helpful in determ inin g the am ount of spinal canal

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Figure 11.243 Lateral radiograph of a child with

traumatic C2 spondylolisthesis (Hangman fracture). (Reproduced with permission from Beaty JH, Kasser JR. Rockwood and Wilkins’ Fractures in Children. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

A

B

Figure 11.244 (A) Lateral flexion radiograph showing sig-

C

nificant instability at the C3–C4 interspace. (B) The instability does not completely reduce in extension. Note the widening of the spinous processes (arrow). (C) The patient was treated with posterior fusion with iliac crest bone grafting and interspinous wiring. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)


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A

B

C

D

Figure 11.245 Chance fracture with bony and

ligamentous injury. (A, B) Anteroposterior and lateral radiographs of a 14-year-old girl who sustained a high-speed motor vehicle accident. She was a front-seat, restrained passenger. Radiographs demonstrate a probable injury at L4. (C) Sagittal magnetic resonance imaging shows fracture through the L4 vertebral body and complete disruption of the posterior ligamentous complex. (D) Lateral radiograph taken after the patient was treated with posterior spinal instrumentation and fusion. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

comprom ise from retropulsed fragm ents. Th e m ajority of fractures do not cause neurologic impairm ent and have m inim al canal comprom ise; these in juries can be treated with a h alo for 6 to 8 weeks, followed by flexion / exten sion radiograph s to docum en t stability. Th ose fractures associated with neurologic deficits or significant canal com prom ise m ay require surgical decom pression an d stabilization.

Thoracolumbar Fractures Compression fractures occur due to an axial load with som e degree of flexion . In th ese in juries, th e an terior vertebral body collapses m ore th an th e posterior wall, resultin g in anterior wedgin g of the vertebrae. Falls are the m ost com m on m echanism of in jury. Fractures can occur at single or m ultiple levels depending on the severity of injury. Usually,

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diagn osis is straigh tforward given th e radiograph ic fin din gs an d complain ts of localized pain . For th ose cases in which th e acuity of in jury is un certain, MRI can be useful. Most compression fractures are stable an d can be treated symptom atically with a TLSO for 6 to 8 weeks. Rarely, local kyph osis can be severe en ough (> 40 degrees) to warrant posterior in strum en tation an d fusion . Burst fractures occur from sim ilar m ech anism s as com pression fractures but result from h igh er-en ergy in juries. In addition to affectin g th e an terior colum n , th e fracture exten ds th rough th e posterior wall of th e vertebral body. Neurologic in jury can result from spin al can al en croach m en t by retropulsed bony fragm en ts. Determ in in g th e stability of th ese fractures can be difficult but usually relies on an in tact posterior ligam en tous complex. Stable fractures without n eurologic im pairm en t can be treated with brace im m obilization for 2 to 4 m on th s. Un stable fractures an d any in juries associated with n eurologic deficits require surgical decompression an d stabilization th rough an an terior or posterior approach . Ch an ce fractures are ligam en tous or bony in juries th at occur from a flexion -distraction m ech an ism . Classically, Ch an ce fractures occur from lap belt in juries sustain ed durin g m otor veh icle acciden ts. Durin g a fron tal impact, th e torso is driven forward an d flexes over th e restrain in g belt. Th e axis of rotation is an terior to th e spin e resultin g in posterior distraction in juries an d variable degrees of an terior compression ; as a result, all th ree colum n s of th e spin e are affected. A high percentage of Ch ance fractures are associated with in traabdom in al in juries. Th e plan e of in jury can be en tirely th rough bon e, soft tissue, or a com bin ation of th e two (Fig. 11.245). Bony in juries are readily diagn osed on lateral radiograph s. If th e in jury is purely ligam en tous, h owever, th e on ly radiograph ic fin din g m ay be subtle widen in g of th e spin ous processes. MRI is usually in dicated to assess th e spin al cord an d th e in tegrity of the posterior ligam entous complex. Pure bony injuries can be treated with exten sion bracin g or castin g (often with thigh exten sion). Ch ance fractures with ligam entous com pon en ts, sign ifican t abdom in al in jury, or n eurologic im -

Sectio n 3

pairm en t sh ould be treated with posterior in strum en tation and fusion.

Spinal Cord Injury without Radiographic Abnormality Th e acronym SCIWO RA refers to Spin al Cord In jury With out Radiograph ic Abn orm ality an d is alm ost exclusively a pediatric in jury. As its n am e im plies, SCIWORA is ch aracterized by a spin al cord in jury in a patien t with n orm al radiograph s. Th e in jury is th ough t to result from greater elasticity of th e spin al colum n relative to th e spin al cord that can allow for spinal cord stretch. Vascular insults to the cord have also been suggested as a possible etiology. Neurologic in jury can be partial or complete, an d th e on set of sym ptom s can be delayed. MRI is th e diagnostic m odality of ch oice an d can reveal edem a, h em orrh age, or con tusion of th e spin al cord. Treatm en t con sists of im m obilization to preven t furth er n eurologic deficit.

RECOMMENDED READINGS Cavalier R, Herm an MJ, Cheun g EV, et al. Spondylolysis and spondylolisthesis in children an d adolescents, I: diagnosis, natural history, and nonsurgical m anagem ent. J Am Acad Orthop. 2006;14:415 – 424. Cheung EV, Herm an MJ, Cavalier R, et al. Spondylolysis and spondylolisthesis in children and adolescents, II: surgical m anagem ent. J Am Acad Orthop. 2006;14:488 –498. Guille JT, Sh erk HH. Congenital osseous an om alies of the upper and lower cervical spine in children. J Bone Joint Surg Am. 2002;84:277 – 288. Hedequist D, Em an s J. Con gen ital scoliosis. J Am Acad Orthop. 2004; 12:266 –275. Lenke LG, Betz RR, Harm s J, et al. Adolescent idiopathic scoliosis: a n ew classification to determ ine th e exten t of spinal arthrodesis. J Bone Joint Surg Am. 2001;83:1169 –1181. McMaster MJ, Ohtsuka K. The natural history of congenital scoliosis: a study of 251 patien ts. J Bone Joint Surg Am. 1982;64:1128 –1147. Newton PO, ed. Adolescent Idiopathic Scoliosis Monograph. Rosem ont, IL: Am erican Academy of Orthopaedic Surgeons; 2004. Skaggs DL, Flyn n JM. Staying Out of Trouble in Pediatric Orthopaedics. Ph iladelphia, PA: Lippin cott William s & Wilkins; 2006. Weinstein SL, Dolan LA, Spratt KF, et al. Health and fun ction of patien ts with un treated idiopath ic scoliosis: a 50-year n atural h istory study. JAMA. 2003;289:559 –567.

Pediatric Musculo skeletal Trauma Wudbhav N. San k ar

O rth opaedic in juries in ch ildren differ from th ose in adults for both biologic an d m ech an ical reason s (Table 11.8). Fractures in ch ildren are m ore com m on an d m ore likely to occur after seem in gly in sign ifican t traum a. Although m ost fractures in children are easier to m an-

John M. Flynn age because of the rapidity an d certainty of bony un ion and the ability of the child’s bones to rem odel, several specific fractures can be problem atic an d require proper un derstan din g an d treatm en t to ach ieve an optim al result.


399

TABLE 11.8

BIOLOGIC AND MECHANICAL DIFFERENCES BETWEEN CHILDREN AND ADULTS Children

Adults

Active skeletal growth Thick, osteogenic periosteum Improved vascular supply Bones less brittle Physis at risk for fracture High remodeling potential

Skeletal maturity Thin, less osteogenic periosteum Inferior blood supply Bones more brittle Ligaments more likely to fail Low remodeling potential

CHARACTERISTICS OF THE IMMATURE SKELETON INFLUENCING PEDIATRIC INJURIES One m ajor biologic difference between adults and children is the phen om enon of active skeletal growth. In children, the m ach inery for skeletal growth is already “turn ed on,’’ an d this results in rapid rem odelin g of fractures from both physeal an d apposition al growth . Th e periosteum is th e secon d m ajor biologic differen ce between ch ild an d adult. In the adult, the periosteum is a relatively thin fibrous m em bran e th at is n ot actively osteogen ic. In th e ch ild, h owever, this periosteum is extrem ely thick, h igh ly vascular, and osteogen ic. In fact, th e periosteum of th e ch ild is dual layered, with an outer fibrous layer an d an in n er osteogen ic (cam bial layer). Th is dual layer reflects its two purposes: th e inn er “biologic’’ layer facilitates fracture h ealing and the outer “m ech an ical’’ layer acts as a th ick skin , wh ich m in im izes fracture displacem ent. Another biologic differen ce is that th e blood supply to the bone in children is reportedly richer, leading to m ore rapid an d certain un ion . However, in certain areas, th e circulation is as tenuous as in the adult. The fem oral head an d the lateral condyle of the distal h um erus are two examples of anatom ic regions th at are highly vulnerable to avascularity and n ecrosis due to a fragile blood supply. Mech an ical differen ces also exist between th e youn g an d aging skeleton. Im m ature bone is less brittle than m ature bon e. As a result, a ch ild’s bon e can deform plastically un der a given load with out n ecessarily fracturin g com pletely through (Fig. 11.246). Unlike adults, incomplete fractures are not un com m on in this age group. Green stick and torus fractures are examples of this un ique ability of th e child’s bon e to plastically deform . Th e ultim ate m ech an ical differen ce in th e ch ild is th e presen ce of a “flaw’’in th e lon g bon e. Th is flaw, th e physis, is the weakest segm en t in a child’s bone, and as a result, it is often th e first poin t of failure durin g th e application of excessive load. As a general principle, children less com m only sustain ligam entous injuries because the growth plate usually fails first (Fig. 11.247). An injury that would produce

Figure 11.246 Plastic deformation of the forearm, resulting in approximately 15 degrees of apex dorsal angulation. (Reproduced with permission from Beaty JH, Kasser JR. Rockwood and Wilkins’ Fractures in Children. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

a sprain or dislocation in an adult is m ore likely to result in a physeal fracture in a child. These fractures m ay be subtle, and stress radiographs or m ore sophisticated im aging m ay be required to docum ent th e fracture if the initial radiograph s are in con clusive. A typical exam ple is th e distal fibular physeal fracture, which can often be m istakenly diagnosed as an an kle sprain . Fifteen to th irty percen t of all skeletal in juries in ch ildren in volve th e physis. Alth ough physeal fractures are classically th ought to occur th rough the zone of provisional calcification (with in th e hypertroph ic zon e), th ey can actually occur through all four zon es. Depending on the entrance and exit of the fracture lin e, physeal fractures can be classified accordin g to th e Salter–Harris classification (Fig. 11.248). It is worth m en tion in g th at in Salter–Harris type II fractures, th e m etaphyseal fragm en t is also kn own as th e Thurston –Holland fragment. In certain cases, th is fragm en t is large enough to accept fixation and is often used to guide fracture reduction. Although an open physis certainly contributes to the rapid h ealin g of ch ildren ’s fractures, it also provides a source of un ique com plications compared with adults. In jury to th e physis can result in a partial or complete growth arrest. Sh ould th e arrest be com plete, th e resultin g

400


B

A

Figure 11.247 (A) In skeletally mature patients with closed physes, tensile failure usually occurs across the ligament. (B) In skeletally immature patients with open physes, failure usually occurs across the physis. (Reproduced with permission from Beaty JH, Kasser JR. Rockwood and Wilkins’ Fractures in Children. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

growth slowdown could result in a lim b len gth discrepan cy. If th e arrest is partial, on e side of th e growth plate could sh ut down and an angular deform ity m ay develop as th e ch ild grows asym m etrically. After a physeal fracture, follow-up radiographs should be carefully assessed for prem ature physeal closure an d divergen t Park–Harris growth lines (Fig. 11.249). These lines appear in the m etaphysis after temporary periods of slowed growth (e.g., traum a, illness). Resumption of norm al growth is m arked by a parallel progression of th e Park–Harris lin e away from the physis.

I

II

Lack of progression m ay indicate a complete arrest, and an oblique Park–Harris lin e implies a partial arrest. Fin ally, because of th e “turn ed on m ach in ery,’’th e active periosteum , an d (usually) im proved blood supply, ch ildren ’s fractures h ave a superior rem odelin g poten tial com pared with adults. As a result, th e orth opaedic surgeon is frequently able to accept reductions in a ch ild that would be con sidered com pletely in adequate in th e adult. Depen ding on the anatom ical region, a certain am ount of displacem ent, overriding, and an gulation (especially in th e plan e

III

IV

V

Figure 11.248 Salter–Harris classification of physeal fractures. In Salter–Harris type I fractures, the

fracture line is entirely within the physis. In Salter–Harris type II fractures, the fracture line extends from the physis into the metaphysic; in Salter–Harris type III fractures, the fracture enters the epiphysis from the physis and almost always exits the articular surface. In Salter–Harris type IV injuries the fracture extends across the physis from the articular surface and epiphysis, to exit in the margin of the metaphysic. Salter–Harris type V fractures were described by Salter and Harris as a crush injury to the physis with initially normal radiographs with late identification of premature physeal closure. (Reproduced with permission from Beaty JH, Kasser JR. Rockwood and Wilkins’ Fractures in Children. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)


401

of an atom ic reduction an d in tern al fixation . Physeal fractures with any con cern in g degree of displacem en t sh ould be reduced gen tly to m in im ize traum a to th e growth plate. Depen din g on th e an atom ic region , th e physis m ay n eed to be stabilized with in tern al fixation . If it is n ecessary to cross the physis with hardware to achieve adequate fixation, sm ooth pins are usually used to m inim ize the possibility of growth arrest.

PEDIATRIC POLYTRAUMA

A

B

Figure 11.249 Distal tibial growth arrest. (A) Distal tibial physeal

Salter–Harris type IV injury treated with cast immobilization without reduction. (B) Two years later, there is varus angulation to the distal tibia from a medial physeal bar. The Park–Harris growth arrest line is not parallel to the distal physis and indicates a partial arrest. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

of join t m otion ) will be corrected by th is rem odelin g ph enom en on (Fig. 11.250). There is a lim it to the am oun t of rem odelin g th at can be ach ieved; for example, rotation al deform ities are rarely am en able to th is type of correction . It is importan t to rem em ber th at rem odelin g depen ds on the presence and proxim ity of an active physis; therefore, adolescents with closing physes have decreased rem odeling poten tial an d sh ould be treated m ore like adults.

GENERAL TREATMENT PRINCIPLES On the basis of the improved biology of fracture healing, m ore pediatric fractures can be treated with cast im m obilization (with or without reduction ) than adult fractures. Ch ildren h ave higher activity levels th an do adults and are often less com plian t with activity restriction s. Th ese issues sh ould be considered before discontinuing im m obilization. In spite of the predom inance of nonoperative treatm en t for children’s fractures, certain injuries n ecessitate operative in terven tion . O pen fractures sh ould be treated with form al irrigation an d debridem en t in th e operatin g room , followed by appropriate fracture specific treatm en t. In traarticular fractures with any sign ifican t degree of displacem en t (> 2 m m ) should be treated with adult principles

Approxim ately 10% of all pediatric traum a patien ts adm itted to th e h ospital are victim s of m ultiple in juries. Traum a is th e leadin g cause of death in ch ildren , accoun tin g for m ore fatalities an d disabilities th an all oth er causes com bin ed in children older than 1 year. Motor vehicle acciden ts involving the ch ild as a passenger, pedestrian, or bicyclist are the m ost com m on m echan ism s of pediatric polytraum a. An aggressive team approach for these severely in jured children is required, including input from general surgeons, n eurosurgeons, pediatrician s, an d em ergen cy departm ent physician s. In itial m an agem en t con sists of en surin g th e stan dard ABCs (airway, breathin g, an d circulation). After com pletion of th e prim ary survey an d stabilization of th e patien t, th e secon dary survey is con ducted in a m an n er sim ilar to stan dard adult traum a protocols. Certain differences in the anatomy and physiology of pediatric patien ts can provide un ique ch allen ges. Com pared with adults, ch ildren h ave relatively large ton gues, sm aller m ouths, and sm aller laryn xes, which can m ake intubation m ore difficult. The head of a child is proportionately larger; as a result, im m obilization on a standard adult spin eboard will flex th e neck and could exacerbate any cervical spine injury. The protuberant abdom en in children offers less protection to vital organ s from eith er th e rib cage or th e pelvis, con sequen tly pediatric patien ts h ave a h igh er in cidence of intraabdom in al in juries. Ch ildren an d adults also have physiologic differences that impact th eir care as polytraum a patien ts. In th e pediatric population , tachycardia is able to com pen sate for large in travascular volum e losses; th erefore, decreased blood pressure is usually a late sign of hypovolem ic shock. Hypotherm ia is also m ore prevalent in children due to the large surface area to body weigh t ratios. Outcom es in children can be predicted by using the m odified injury severity scale (MISS), as described by Mayer (Table 11.9). This has proved to be useful in predictin g m orbidity an d m ortality rates in th e pediatric age group. Th e MISS em ploys th e Glasgow com a scale for grading th e n eurologic injury; in addition , it reviews dam age to individual body areas, such as the face and neck, th e chest, th e abdom en , an d th e extrem ities. Rapid evaluation of th e pediatric polytraum a patien t can be assessed also by usin g th e Pediatric Traum a Score (Table 11.10). Several compon en ts such as size, airway in tegrity, cen tral n ervous system

402


A,B

C

Figure 11.250 (A) Injury radiograph of a 7-year-old

D

E

child with a distal radial metaphyseal fracture. (B and C) Lateral and anteroposterior views of the same patient taken 1 month later, showing development of 45 degrees of angulation in the sagittal plane and 40 degrees in the coronal plane. (D and E) True appearance taken 4 years later shows only 10 degrees of residual angulation in the sagittal plane and full correction of coronal plane angulation. The patient had full range of motion, equal to that of the opposite extremity, and was asymptomatic. (Reproduced with permission from Beaty JH, Kasser JR. Rockwood and Wilkins’ Fractures in Children. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

403

GSC 13-14

Abrasion or contusions of ocular apparatus or lid Vitreous or conjuctival hemorrhage Fractured teeth

Muscle ache or chest-wall stiffness

Muscle ache, seat-belt abrasion

Minor sprains Simple fractures and dislocations

Neural

Face and neck

Chest

Abdomen

Extremities and pelvic girdle

Open fractures of digits Non-displaced long-bone or pelvic fractures

Major abdominal-wall contusion

Simple rib or sternal fracture

Undisplaced facial-bone fracture Laceration of eye, disfiguring laceration Retinal detachment

GSC 9-12

2—Moderate

Displaced long-bone or multiple hand or foot fractures Single open long-bone fracture Pelvic fractures with displacement Laceration of major nerves or vessels

Contusion of abdominal organs Retroperitoneal hematoma Extraperitoneal bladder rupture Thoracic or lumbar spine fractures

Multiple rib fractures Hemothorax or pneumothorax Diaphragmatic rupture Pulmonary contusion

Loss of eye, avulsion of optic nerve Displaced facial fracture “Blow-out” fracture of orbit

GSC 9-12

Multiple closed long-bone fractures Amputation of limbs

Minor laceration of abdominal organs Intraperitoneal bladder rupture Spine fractures with paraplegia

Open chest wounds Pneumomediastinum Myocardial contusion

Bone or soft-tissue injury with minor destruction

GSC 5-8

4—Severe, Life-Threatening

Multiple open long-bone fractures

Rupture or severe laceration of abdominal vessels or organs

Lacerations, tracheal hemomediastinum Aortic laceration Myocardial laceration or rupture

Injuries with major airway obstruction

GSC 4

5—Critical, Survival Uncertain

GSC = Glasgow Comma Scale. (Adapted from Mayer T, Matlak ME, Johnson DG, Walker ML: The Modified Injury Severity Scale in pediatric multiple trauma patients. J Pediatr Surg. 1980;15:719; and from Green NE, Swiontkowski MF: Skeletal Trauma in Children, Vol 3. Philadelphia, WB Saunders, 1998.)

1—Minor

Body Area

3—Severe, Not Life-Threatening

THE MODIFIED INJURY SEVERITY SCALE (MISS) FOR MULTIPLE INJURY CHILDREN

TABLE 11.9

404


TABLE 11.10

PEDIATRIC TRAUMA SCORE Variable

+2

+1

−1

Weight (kg) Airway patency Systolic blood pressure (mm Hg) Neurologic Open wound Skeletal trauma

> 20 Normal > 90

10–20 Maintained 50–90

< 10 Unmaintained < 50

Awake None None

Obtunded Minor Closed

Comatose Major Open or multiple

(Reprinted with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

in tegrity, systolic blood pressure, th e presen ce or absen ce of open woun d, an d th e am oun t of skeletal dam age can be used to rapidly assess th ese patien ts. Total poin t coun ts greater th an 8 predict an excellen t progn osis for survival; scores less than 0 indicate a very high risk of death. When evaluatin g orth opaedic in juries in the polytraum a patien t, it is importan t to rem em ber th at ch ildren ten d to be better able to survive extrem ely severe in juries an d frequen tly respon d better to a given in jury th an do adults. As a result, care m ust be taken n ot to overlook m usculoskeletal in juries or to delay treatm en t any lon ger th an absolutely necessary in the m ultiply in jured ch ild, as this can result in future problem s. A com m on example is the head-injured ch ild with a supracon dylar elbow fracture wh o receives late treatm en t for h is elbow in jury because of prolon ged con cerns for the safety of the brain. One year later, the child has m ade a full n eurologic recovery an d h is on ly complain t is about th e m alun ion of h is elbow an d th e resultin g loss of elbow m otion . Good com m un ication between orth opaedic surgeons, traum a surgeons, and neurosurgeon s is essen tial to en sure safe an d tim ely treatm en t of all in juries.

UPPER EXTREMITY Shoulder and Arm Injuries Clavicle Fractures and Dislocations Fractures of th e clavicle occur in all age groups, from th e neonate to the adult. Birth fractures of th e clavicle are th e m ost com m on fracture in th e n ewborn . Frequen tly, th e diagn osis can be m ade in th e n ursery wh en th e ch ild develops pseudoparalysis of th e in volved lim b an d an asym m etric Moro reflex. It is importan t to evaluate th e ch ild for associated brach ial plexus palsy as both condition s can result from a difficult delivery. Treatm ent for these clavicle in juries sh ould be simple im m obilization of th e extrem ity with a soft wrap of cast padding or stockinette. Healin g is rapid, and lon g-term sequelae are virtually nonexistent.

In older patien ts, diaphyseal fractures are th e m ost com m on injury to th e clavicle. Typically, these fractures result from a fall onto th e poin t of the shoulder, and the diagnosis is straightforward: patients have ten derness along th e clavicular shaft, associated with pain on m otion of the upper extrem ity. Stan dard treatm en t is brief im m obilization in a slin g or figure-of-8 dressing. Rapid h ealing in 3 to 6 weeks is expected, with restoration of full m otion, function, and strength in m ost patients. Parents should be warn ed about th e “bum p’’ or m ass of callus th at can form aroun d th ese fractures. This m ass resolves with norm al growth and rem odeling. Recent concerns in adults regardin g m alunion, n onun ion , and refracture h ave caused a tren d toward open reduction an d in tern al fixation of m arkedly displaced m idsh aft clavicle fractures. The indications for operative fixation in adolescents are som ewh at unclear but m ay have a role in severely displaced fractures in older adolescen ts. Fractures of th e m edial en d of th e clavicle are quite rare, accoun tin g for fewer th an 10% of clavicular fractures. Equally rare are true stern oclavicular dislocation s. Th e clavicle is the first bone to ossify; however, the m edial physis does n ot close un til approxim ately 25 years of age. As a result, m ost m edial in juries to the clavicle are actually physeal fractures that can m im ic a sternoclavicular dislocation . In patien ts with th ese in juries, plain radiograph s are often difficult to interpret, and computed tom ography (CT) scans are usually needed to m ake the diagnosis. Posterior injuries are of particular concern because they can compress the trachea, esophagus, or great vessels (Fig. 11.251). Closed reduction in th e operatin g room with vascular or th oracic surgery support has traditionally been advocated for th ese fractures. Because of concerns about recurren t in stability after closed reduction, m any surgeons are starting to prefer open reduction of th ese in juries. Usually th e m edial clavicle is approach ed an teriorly. Th e fracture is reduced un der direct visualization , an d suture is used to repair th e stern oclavicular join t capsule an d ligam en ts to preserve a stable reduction . Fractures of th e distal en d of th e clavicle also are frequen tly physeal separation s. Th e distal physis rem ain s open un til approxim ately 19 years of age. Th e persisten ce of th is open physis alon g with th e presen ce of a th ick periosteal sleeve aroun d th e distal clavicle m akes physeal fractures m ore com m on than true lateral clavicular fractures. Once the physis closes, an acrom ioclavicular separation is th e usual in jury. Again , th e in jury typically results from a fall on to the poin t of th e sh oulder an d sim ple radiograph s are usually adequate to m ake th e diagn osis. Sh ortterm slin g im m obilization is sufficien t for m ost of th ese injures.

Fractures of the Proximal Humerus and Humeral Shaft Proxim al h um erus fractures can be eith er physeal or m etaphyseal but usually are Salter–Harris type I or type II in juries. Physeal separation s h ave been described in

405


A

C Figure 11.251 Sternoclavicular separation. This 14-

B

neonates, but m ost in juries occur in adolescents. Th e geom etry of th e proxim al h um eral physis is n ot plan ar but rath er “tent shaped,’’ with the apex located posterom edially. Before closin g between the ages of 14 and 18, the proxim al hum eral physis con tributes 80% of th e growth of th e total hum erus. Because of th is large growth potential, a trem en dous am oun t of deform ity can be accepted an d expected to rem odel (Fig. 11.252). Furth erm ore, th e vast ran ge of m otion of the glenohum eral joint perm its adequate com pen sation for any residual deform ity. As a result, closed treatm ent with sling im m obilization is recom m en ded for alm ost all pediatric patients with either a m etaphyseal or physeal fracture of th e proxim al h um erus. Closed reduction and percutaneous pin fixation is generally not necessary unless a child has greater th an 40 degrees of m alalign m en t and is nearing skeletal m aturity. One definite indication for open reduction and internal fixation is a biceps ten don en trapped in th e fracture site. Fractures of th e h um eral sh aft are un com m on in ch ildren ; wh en seen , th e ch ild is usually older th an 12 years or youn ger th an 3 years. It is critically im portan t to recognize th e association between spiral fractures of the h um eral sh aft an d child abuse. In children youn ger th an 3 years, an acute torsional injury to th e upper extrem ity typically produces th is un ique spiral lesion . If th ere is an in con sisten t history of injury, delay in presen tation for care, or associated injuries in these children, additional investigation into possible abuse is warran ted. Hum eral sh aft fractures h ave also been reported in neonates following difficult delivery an d, m uch like clavicle fractures, are h eralded by pseudoparalysis of th e upper extrem ity (Fig. 11.253). Because of compen satory sh oulder an d elbow ran ge of m otion , up to 30 to 40 degrees of m alalign m en t is acceptable. As a result, th e vast m ajority of h um eral sh aft fractures can be

year-old boy sustained an injury to the right clavicle during a wrestling match when his shoulder was compressed against his chest wall. He complained of shortness of breath, especially when he extended his neck. (A) The anteroposterior radiograph demonstrates asymmetry of the sternal position of the clavicle. (B) The computed tomographic scan demonstrates posterior displacement of the medial end of the right clavicle, which is near the trachea (arrow). (C) A three-dimensional reconstruction, with a cephalic projection, demonstrates the posterior and midline displacement of the clavicle. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

treated by closed m eth ods, such as collar an d cuff, fun ction al brace, or slin g im m obilization . Most fractures are “sticky’’ by 4 weeks, and m obilization can occur at this tim e. Select polytraum a victim s (usually adolescen ts) m ay be can didates for operative treatm en t. In th ese rare cases, both titan ium elastic n ails an d plate fixation h ave been used with good success. Radial n erve in juries associated with h um eral sh aft fractures are usually due to a con tusion sustain ed durin g in itial fracture displacem ent. These palsies are classically associated with fractures at th e jun ction of th e m iddle an d distal third (Holstein –Lewis fractures). True entrapm ent of the radial nerve in the fracture site is rare; therefore, alm ost all ch ildren with radial n erve in juries sh ould be observed with th e expectation of full recovery. If the radial nerve fails to recover by 3 to 4 m on th s, electrodiagn ostic studies an d surgical exploration are warran ted.

Elbow Injuries No in jury gen erates as m uch an xiety for orth opaedic surgeon s un accustom ed to treatin g ch ildren as do elbow fractures. There is good reason for th is: a sm all swollen elbow is difficult to exam ine, n eurovascular structures are often at risk, an d radiograph s can be difficult to in terpret because of m ultiple evolvin g ossification cen ters. Th e an atom y of th e ch ild’s elbow differs dram atically from th at of th e adult. At birth , n o epiphyseal structures are presen t. Th e first secon dary ossification cen ter to appear is th at of th e capitellum , usually observed at 6 m onths of age. Following that, in order of appearan ce, the ossification cen ters of the radial h ead, m edial epicon dyle, troch lea, olecran on , an d the lateral epicon dyle are seen (Fig. 11.254). In itially, th ese are all parts of on e large ch on droepiphysis. With rapid differen tial

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A,B

C

D,E

F

G

I

H

J Figure 11.252 Proximal humeral fracture in a 12-year-old boy. (A) the initial fracture was treated

with a sling and swathe. (B and C) Three months after injury, healing and early remodeling are evident. (D and E) One year after injury, remodeling continues. (F and G) Four years after injury, remodeling is complete. (H–J) The patient has recovered full range of motion but has a 1 cm arm length discrepancy. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)


407

growth , th e m edial epicon dyle form s its own ossification cen ter, an d th e capitellum , troch lea, an d lateral epicon dyle becom e on e cen ter. Proper un derstan din g of th e sequen ce, tim ing, an d appearance of these secondary ossification cen ters is essen tial for in terpretin g pediatric elbow in juries. Even with th is kn owledge, it is still often difficult to distinguish a subtle fracture from a norm al ossification center, an d radiograph s of th e con tralateral elbow can provide m uch n eeded clarity. If the diagnosis rem ains uncertain, ultrasoun d, arth rography, or m agn etic reson an ce im agin g (MRI) m ay be necessary to avoid m issing an important injury.

Figure 11.253 Fracture of the humeral shaft sustained at birth demonstrates significant callus by the age of 14 days and was probably comfortable enough in 7 days to obviate the need for any immobilization. (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

7 years of age (5–9 years)


1 year of age (1–26 months)


Figure 11.254 Ossification of the secondary centers of the dis-

tal humerus. The average ages are specified, and the age ranges are indicated. The ossification ranges are earlier for girls than for boys. The lateral epicondyle, capitellum, and trochlea coalesce between 10 and 12 years of age, subsequently fusing to the distal humerus between 13 and 16 years of age. This is about the time that the medial epicondyle fuses to the proximal humerus. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Supracondylar Humerus Fractures If elbow in juries as a group gen erate th e m ost an xiety for orth opaedic surgeon s, th en supracon dylar h um erus fractures are certainly th e biggest culprit. The complications of th is in jury, as well as th e treatm en t, are legen dary in th e pediatric orth opaedic literature. Satisfactory lon g-term outcom es are n ot guaran teed even with an atom ic reduction . However, techn iques and practices th at have advanced over th e last two decades h ave sign ifican tly reduced th e n um ber of serious com plication s. Supracon dylar fractures are th e m ost com m on elbow fractures in children, accounting for roughly 60% of all pediatric elbow in juries. Th e in ciden ce of supracon dylar fractures is correlated with age as it is alm ost exclusively an injury of the im m ature elbow; the peak incidence of th ese fractures is between th e ages of 5 an d 7 years. Boys are m ore affected than girls, by a 3:2 ratio. There are two gen eral groups of supracon dylar fractures: exten sion type (95%) and flexion type (5%) (Fig. 11.255). Each results from different m echan ism s of injury. In th e supracon dylar region of th e h um erus, th ere are two strong colum ns of bone: one m edial an d one lateral. Between them is a cen tral “wafer’’ of bon e, wh ich is often n o thicker than 1 m m . Because of th is dram atic decrease in anteroposterior (AP) diam eter an d the acute change in cross-section al geom etry (from cylin drical to flatten ed), th e supracon dylar region is m ech an ically vuln erable (Fig. 11.256). With hyperexten sion loadin g, th e olecran on levers again st the olecranon fossa an d creates a bending m om ent. Th is can cause ten sile failure of th e an terior surface of th e distal h um erus, resultin g in th e classic exten sion -type in jury. Th e fact th at hyperexten sion loadin g is so com m on accoun ts for the preponderance of these injuries. The few flexion -type in juries seen typically result from a direct fall on th e olecran on , th ereby ben din g th e supracon dylar region in the opposite direction. Th e classification m ost widely accepted is th at proposed by Gartland in 1959. A type I fracture is non displaced and is often diagnosed by a positive posterior fat pad sign (Fig. 11.257). Type II in juries are displaced but h ave an in tact posterior h in ge of periosteum an d bon e, usually m akin g th em stable in extern al rotation . Type III fractures are com pletely displaced an d can be furth er subdivided in to th ose

408


A

B Figure 11.255 (A) Lateral radiograph showing an extension-type supracondylar humerus fracture.

(B) Lateral radiograph demonstrating a flexion-type fracture. (Reproduced with permission from Beaty JH, Kasser JR. Rockwood and Wilkins’ Fractures in Children. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

A

B Figure 11.256 (A) The typical orientation of the fracture line

in a supracondylar fracture. (B) A cross-sectional view through the fracture demonstrates the thin cross-sectional area of bone that is mechanically vulnerable. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

displaced posterolaterally an d th ose displaced posterom edially; th e latter accoun t for approxim ately 75% of th e total. It is importan t to n ote th e direction of displacem en t, because it frequen tly h as an impact on m an agem en t. A m ore recent type IV fracture has been described by Skaggs et al., in wh ich th e periosteum h as been stripped circum feren tially an d the fracture is, therefore, un stable in both flexion an d exten sion . In addition to th e Gartlan d classification , th ere are several radiograph ic m easurem en ts th at are essen tial wh en evaluatin g a supracon dylar h um erus fracture. Th e sin gle m ost importan t m easurem ent is drawn on the lateral view by extending a line down the anterior surface of the h um erus th rough th e elbow join t (Fig. 11.258). If th e line intersects any part of the capitellar ossification center, then the reduction (at least in the sagittal plane) is deem ed acceptable. If, however, th e anterior hum eral lin e falls anterior to th e ossification cen ter, it in dicates exten sion at the fracture site and the need for reduction. On th e AP view, the m ost important m easurem en t is Baum ann angle, wh ich is form ed between a lin e perpen dicular to th e axis of th e h um erus an d a lin e parallelin g th e m etaphysis on the lateral side of the distal hum erus (Fig. 11.259). The n orm al an gle varies between 9 an d 26 degrees. A m easurem en t less th an th is in dicates that the fracture is in varus,


A

409

B

Figure 11.257 Types of supracondylar fractures. (A) Type

C

I fracture is nondisplaced. Often the only evidence is posterior displacement of the olecranon fat pad due to intraarticular blood (large arrows). (B) Type II fracture. Lateral view demonstrates a displaced supracondylar fracture with the posterior cortex intact. (C) Type III fracture is totally displaced. (Reproduced with permission from Beaty JH, Kasser JR. Rockwood and Wilkins’ Fractures in Children. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Figure 11.259 Baumann angle is formed between a line perpenFigure 11.258 In the normal elbow, the anterior humeral line

should intersect the capitellum. (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

dicular to the axis of the humerus and a line paralleling the metaphysis on the lateral side of the distal humerus. The normal angle varies between 9 and 26 degrees. (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

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whereas a m easurem en t greater th an norm al implies a valgus m alalignm ent. Because of the high rate of complications associated with th ese fractures, it is im perative that th e initial evaluation of th ese ch ildren in clude a th orough physical an d neurologic exam ination (and docum en tation of results). Although these patien ts experience pain and anxiety as a result of th e in jury, it is usually possible, even in sm all ch ildren , to con duct an accurate m otor fun ction exam in ation . Evaluation should in clude testing of the m edian, ulnar, and radial nerves (including the an terior interosseus nerve and the posterior interosseus nerve). Th e radial pulse should be palpated, an d th e overall perfusion of th e h an d (i.e., warm an d pink vs. cool an d white) should be assessed. The skin sh ould carefully be evaluated for signs of open fracture, ten tin g from button h oled fracture fragm en ts, an d excessive bruisin g. Th e extrem ity sh ould be exam in ed for com partm en t syn drom e by palpation an d compartm en t pressure m easurem en t if in dicated. Treatm en t of th ese fractures is gen erally based on th e type. Th e m ajor pitfall surroun din g type I in juries is failure to recogn ize th at a given fracture is actually type II. Type I in juries are truly n on displaced. Care sh ould be taken to en sure th at the fracture does n ot have subtle varus im paction; Baum ann angle is often helpful in th e evaluation of this deform ity. If the injury is truly a type I, then th e application of a lon g arm cast, usually for 3 weeks, is sufficien t treatm en t. Type II in juries again can suffer from too casual an approach by th e treatin g surgeon . Alth ough th e posterior cortex is intact by definition, angulation (and progressive exten sion ) can an d does occur. If th e an terior h um eral lin e does n ot in tersect th e capitellum , th en reduction is n ecessary. Alth ough th is reduction can be ach ieved by hyperflexion of the elbow, m ain ten ance of the reduction requires im m obilization in th is position . It is well un derstood th at hyperflexion of th e elbow reduces perfusion to th e h an d; an d th erefore, th e vast m ajority of surgeon s prefer closed reduction an d percutan eous pin n in g (CRPP) in th e operatin g room (followed by im m obilization at less th an 90 degrees of flexion ) for type II in juries. All type III in juries require CRPP. Th e in itial displacem en t, wh eth er it be posterom edial or posterolateral, will in dicate th e location of the intact periosteal hinge. Th e hinge is typically in tact on the side of displacem ent. For example, in the m ore com m on posterom edially displaced in jury, th e periosteal h in ge is m edial. Th erefore, pron ation , wh ich closes th e lateral side and tigh tens th e m edial hinge, is generally employed (alon g with elbow flexion ) to reduce th ese in juries. Likewise, supination an d flexion are usually necessary for posterolaterally displaced fractures. If th e fracture is difficult to reduce, th e proxim al fragm en t m ay be en trapped in th e brach ialis m uscle. Man ipulatin g th e brach ialis by “m ilkin g’’it distally is usually successful in extractin g th e m uscle away from th e m etaphyseal spike. In traoperatively, fluoroscopy sh ould be used to assess th e quality of reduction by using both the anterior h um eral line and Baum ann an-

gle. Rotational and translational residual deform ities are less critical than residual varus or valgus tilt. Late deform ities, which complicate the treatm ent of these injuries, result prim arily from residual tilt in th e coron al an d sagittal plan e th at h ave m in im al rem odelin g poten tial. Open reduction is reserved for th ose few cases of open in juries, compartm en t syndrom e, or irreducible fractures. Con troversy still exists over th e optim al n um ber an d con figuration of pin placem en t. Alth ough crossed m edial and lateral pins have been shown to be m ore stable biom echanically, m ore surgeons are beginning to prefer lateral en try pin fixation because of th e decreased risk of uln ar n erve injury (Fig. 11.260). In gen eral, two lateral entry pin s are sufficient for type II fractures, whereas three pin s are usually n ecessary for type III fractures. As lon g as th e pin s en gage both fracture fragm en ts an d h ave bicortical fixation and adequate spread at the fracture site, lateral-entry pin s h ave been sh own to be as clin ically effective as crossed pin s. If a m edial pin is used, it sh ould be placed after lateral pin placem en t, with th e elbow exten ded to reduce th e risk of an terior subluxation of th e uln ar n erve. After percutan eous pin n ing, ch ildren sh ould be im m obilized in a cast or splin t (depen din g on th e am oun t of soft tissue swellin g) at no m ore than 90 degrees of flexion for 3 to 4 weeks. At th at poin t, pin s are usually rem oved on an outpatien t basis, an d children are allowed to gradually return to their n orm al activities. Complication s of supracon dylar fractures are acute n erve an d vascular injuries an d th e late developm en t of deform ity. Nerve palsies have been reported in approxim ately 7% of patien ts. Alth ough it was tradition ally th ough t th at th e posterior in terosseous n erve (PIN) was th e m ost com m on to be dam aged, recent data suggest th at the anterior in terosseous n erve (AIN) is actually th e m ost com m only injured n erve. The ulnar n erve is th e m ost com m on n erve injured during flexion -type fractures an d as an iatrogen ic result of percutan eous pin n in g (1% –5% in ciden ce). Th e vast m ajority of n erve in juries sustain ed at th e tim e of th e fracture will resolve between 3 an d 6 m on th s an d sh ould th erefore be observed. Ulnar nerve injuries as a result of m edial pin n in g or oth er n erve palsies clearly sustain ed during CRPP should be explored and undergo revision pin n in g if n ecessary. Vascular injuries are also associated with supracondylar hum erus fractures. Often the brach ial artery is ten ted over th e m etaphyseal fragm en t an d teth ered by its supratrochlear branch (Fig. 11.261). True injury to th e artery occurs in 0.5% of cases. Cases of a cold, pulseless h an d represen t a surgical em ergen cy an d sh ould un dergo im m ediate reduction and stabilization. In m ost fractures, the vascularity of the hand will be restored after reduction. If arterial flow is still poor, im m ediate surgical exploration of th e brach ial artery (often with th e h elp of a vascular con sultan t) is n ecessary. Not un com m on ly, a ch ild’s h an d is warm but pulseless on initial evaluation. This is usually th e result of excellen t periph eral an d collateral blood flow


A

B

C

D

411

Figure 11.260 (A and B) Anteroposterior and lateral radiographs of a 4-year-old boy with at type III supracondylar humerus fracture. (C and D) Intraoperative AP and lateral view after closed reduction and percutaneous pinning. (Reproduced with permission from Children’s Orthopaedic Center, Los Angeles, California.)

around the elbow. These children sh ould un dergo CRPP in a tim ely fashion but do not truly constitute a vascular em ergen cy as m ost auth ors h ave dem on strated good results in these patien ts after treatm ent with careful observation an d expedited CRPP without vascular exploration. Com partm en t syn drom e can exist in th e presen ce of a pulse, an d conversely, the absence of a pulse does n ot necessarily m andate exploration of the vessel. Recognition of the clinical signs of compartm ent syndrom e is essential including

in ordin ate levels of pain , pain with passive m otion , an d alteration s in temperature an d h an d fun ction . Th e m ost com m on sign, however, of impen ding compartm en t syn drom e in pediatric patien ts is in creased n arcotic requirem en ts. If in dicated, compartm en t pressures sh ould be m easured an d fasciotom ies perform ed. Failure to appropriately treat a com partm en t syn drom e results in irreversible myon ecrosis an d subsequen t con tracture. Th is con tracture of the volar m usculature of the forearm and th e resulting

412


Figure 11.261 The brachial artery can be tented over the sharp

end of the proximal fragment and tethered by the supratrochlear branch. (Reproduced with permission from Beaty JH, Kasser JR. Rockwood and Wilkins’ Fractures in Children. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

deform ity of th e h an d h ave been iden tified for m any years as Volkm an n isch em ic con tracture (Fig. 11.262). Late deform ity resultin g from th ese fractures is usually due to m alun ion in th e coron al or sagittal plan e. In the coronal plane, this residual tilt results in changes to the carrying angle of th e arm . Cubitus varus (resulting from residual varus) is the m ost com m on angular deform ity an d is classically referred to as th e gunstock deform ity (Fig. 11.263). Alth ough th e deform ity is prim arily cosm etic, there is often a great deal of parental pressure to correct the un sigh tly appearan ce. For sign ifican t deform ities, perform in g a supracon dylar osteotomy is appropriate, alth ough it is best delayed un til adolescen ce to m in im ize th e risk of recurren ce. Valgus deform ity, on th e oth er h an d, ten ds to cause a functional problem . In certain cases, a tardy ulnar nerve palsy can develop. As a result, early surgical correction is warran ted to m in im ize th e risk of irreversible uln ar nerve injury.

Figure 11.263 Cubitus varus from a supracondylar malunion

causing a “gunstock” deformity, which is mostly cosmetic. (Reproduced with permission from Beaty JH, Kasser JR. Rockwood and Wilkins’ Fractures in Children. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Lateral Condyle Fractures of the Humerus Lateral con dyle fractures accoun t for approxim ately 20% of elbow fractures in ch ildren . Th ere is som e debate as to wh eth er th e m ech an ism is avulsion or compression , but m ost auth ors agree that the fracture results from a varus stress to th e extended elbow an d supin ated forearm . These fractures are classified according to the Milch classification, wh ich depen ds on th e location of th e fracture lin e th rough the distal part of th e hum erus (Fig. 11.264). In a Milch type I (Salter–Harris type IV) injury, the fracture line is lateral to the trochlear groove and the elbow ten ds to rem ain stable.

A

B

Figure 11.264 Physeal fractures of the lateral condyle. (A) Milch Figure 11.262 Volkmann ischemic contracture caused by a

supracondylar fracture of the humerus. (Reproduced with permission from Berger RA, Weiss AP. Hand Surgery. Philadelphia, PA: Lippincott Williams & Wilkins, 2004.)

type I injury with the fracture line lateral to the trochlear groove. (B) Milch type II fracture extending medial to the ossific nucleus of the lateral condyle. (Reproduced with permission from Beaty JH, Kasser JR. Rockwood and Wilkins’ Fractures in Children. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)


413

B A

Figure 11.265 A minimally displaced lateral condyle

C

fracture may be best visualized on the oblique radiograph. Anteroposterior (A), lateral (B), and internal oblique (C) radiographs. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

In a Milch type II (Salter–Harris type II) injury, th e fracture line extends m edial to the trochlear groove, and because of the loss of the troch lear buttress, th e ulna and radius often displace laterally. Great care m ust be taken in assessm en t of fracture displacem en t, as th e full exten t of th e fracture lin e can be difficult to perceive on stan dard plain radiograph s. Th ere is a ten den cy to th in k th at m any of th ese fractures are n on displaced, wh en actually th ere is a sm all am oun t of rotation or translation. O blique radiographs or arthrogram s are useful in determ in ing the degree of displacem ent (Fig. 11.265). On th e basis of displacem en t, fractures can be categorized as type I (< 2 m m displacem ent), type II (2 –4 m m displacem en t), and type III (> 4 m m displacem en t). In all cases, th e goal of treatm ent is an atom ic align m ent and healing since these fractures not only involve the physis but are also intraarticular. Treatm en t of type I fractures is som ewh at con troversial. Truly nondisplaced fractures are at low risk for displacem en t in a cast an d can , th erefore, be treated with cast im m obilization for 3 to 6 weeks. However, even m inim ally displaced type I fractures (< 2 m m ) can displace

late, with an in creased risk of n on un ion , in up to 10% of cases. As a result, any lateral con dyle fracture treated conservatively in a cast should be m onitored closely to avoid loss of articular and physeal alignm ent (Fig. 11.266). Type II an d III fractures with m ore sign ifican t displacem en t (> 2 m m ) are usually treated with reduction an d stabilization . For som e type II fractures with out m alrotation , CRPP can be perform ed. In m ost cases, arth rography is used to con firm articular con gruity at th e tim e of th e pin n ing. For m ore displaced type II fractures an d all type III fractures, open reduction and intern al fixation is the standard of care. Th e fracture site is exposed th rough th e in terval between th e brach ioradialis an d th e triceps, with care taken not to strip the posterior soft tissue attachm ents to th e con dyle, as th is would disrupt th e blood supply to the capitellum . An terior exposure of the joint allows for an atom ic reduction , an d th en two or th ree K-wires are used to m ain tain th e reduction for 3 to 6 weeks. It is n ot un com m on for patien ts to develop a lateral spur on th e lateral condyle as a result of periosteal disruption; warning parents about th is “bump’’ah ead of tim e can preven t un n ecessary worry.

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A,B

C

D,E

F Figure 11.266 The drifting lateral condyle fracture. (A and B) Anteroposterior (AP) and lateral

radiographs at presentation. This lateral condyle fracture had only approximately 2 mm of displacement on the AP view. No displacement is noted on the lateral view. The child was placed in a long arm cast and a follow-up 1 week later was recommended. (C and D) AP and lateral radiographs taken 1 week after injury show further displacement of the lateral condyle fracture, with 5 mm of separation of the lateral condyle from the distal humerus. Open reduction and pinning was performed. (E and F) Radiographs taken in the cast 4 weeks after open reduction and pinning show anatomic alignment and early healing. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Sim ilar to supracon dylar h um erus fractures, lateral condyle fractures have th eir own share of complications. Growth arrest is un com m on but can occur across th e distal h um eral physis, causin g a “fish tail’’ deform ity of th e distal h um erus. Cubitus varus can result from m alun ion , lateral colum n overgrowth, or trochlear osteonecrosis and un dergrowth . Non un ion can occur perh aps because of th e tenuous blood supply or because th e fragm en t is bath ed in synovial fluid. Treatm en t is difficult and is often dictated by the degree of displacem ent. Fractures displaced less than 1 cm can be treated with in situ screw fixation and bone grafting. Because of the h igh risk of osteonecrosis with excessive dissection , n on un ion s displaced m ore th an 1 cm m ay be better off observed. Cubitus valgus can occur as a result of

n on union and collapse of the lateral colum n. A tardy uln ar nerve palsy can develop from this deform ity and m ay require corrective osteotomy an d uln ar n erve tran sposition .

Medial Epicondyle Fractures Accounting for 10% of elbow fractures and occurring in an older age group, m edial epicondyle fractures are associated with elbow dislocations in up to 50% of cases. Th e application of valgus stress can avulse th e m edial epicon dyle and subsequently cause the elbow to dislocate. The flexor–pronator m uscle m ass originates partly from the epicon dyle and acts to displace the fracture further as it shorten s. In gen eral, th e exten t of displacem en t is th e criteria for treatm ent. Nondisplaced fractures and fractures displaced

415


A

B Figure 11.267 (A) Anteroposterior view showing an elbow dislocation with an incarcerated medial

epicondyle fracture within the joint (arrow). (B) Lateral view of the same elbow demonstrates the fragment (arrow) between the humerus and olecranon. (Reproduced with permission from Beaty JH, Kasser JR. Rockwood and Wilkins’ Fractures in Children. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

less than 5 m m are generally treated by short-term im m obilization followed by early ran ge-of-m otion exercises to m inim ize th e risk of elbow stiffness. Surgical treatm ent for fractures displaced m ore than 5 m m is extrem ely controversial since studies have sh own that fibrous unions and nonunions cause little fun ctional deficits. Som e surgeons favor open reduction an d in tern al fixation for th ese fractures in those patien ts who participate in repetitive valgus stress activities (pitching an d gym nastics). The only defin ite indication for operative treatm ent is a displaced m edial epicon dyle fragm ent, which is in carcerated in the join t (Fig. 11.267). Surgical dissection proceeds through a m edial approach . Th e uln ar n erve is iden tified an d protected, an d th e fragm ent is reduced by flexing the elbow. Rigid internal fixation using a compression screw is preferred to allow early m obilization and prevent elbow flexion con tracture. Because of its proxim ity to the fracture fragm en t, uln ar nerve injury is relatively com m on , occurring in 10% to 16% of cases. Som e loss of term in al exten sion is com m on after treatm en t but can be m in im ized by early m obilization . Non un ion s m ay occur in over 50% of patien ts treated con servatively, but as previously m en tion ed, th is appears to have little function al con sequence.

Fractures of the Distal Humeral Physis Fractures th rough th e distal h um eral physis are rare an d m ost often occur before the age of 6 or 7 years. The m echan ism of injury is un known but m ost likely involves rotatory forces on th e elbow, often from ch ild abuse or birth traum a. DeLee classified these fractures as group A, occur-

ring in children up to 12 m on th s of age, before th e appearan ce of capitellum ossification cen ter. Th ese in juries are usually Salter–Harris type I fractures and are difficult to diagn ose because of th e lack of ossification cen ters in the distal fragm en t. Group B fractures occur in ch ildren between 12 m on th s an d 3 years of age wh en th ere is defin ite ossification of th e lateral con dylar epiphysis. Th ese, too, are usually Salter–Harris type I fractures. Group C fractures occur in older ch ildren (3 –7 years of age) an d are associated with a large m etaphyseal fragm en t. Group C fractures can be distinguished from a low supracondylar fracture by the sm ooth outline of the distal h um erus. A distal h um eral physeal separation sh ould be con sidered in any child youn ger than 18 m onths with a swollen elbow. Radiograph ic diagn osis can be difficult, especially in group A, because of th e lack of ossification cen ters. On e key con cept to rem em ber is th at in a distal h um eral physeal fracture, the relationship of the ulna to the radius is m aintain ed but both are displaced posterom edially in relation to th e distal h um erus (Fig. 11.268). Although these injuries are often con fused with elbow dislocation s, it is importan t to rem em ber th at dislocation s are exceedin gly rare in ch ildren of th is age. In an elbow dislocation , th e displacem en t of th e proxim al radius an d uln a is alm ost always posterolateral, an d th e relation sh ip between th e proxim al radius an d lateral con dylar epiphysis (wh en it appears) is disrupted. If diagnosis is still uncertain , ultrasoun d or arth rography can be used to outlin e th e epiphysis of th e hum erus. Neon ates an d extrem ely sm all in fan ts can be treated with closed reduction and cast im m obilization at

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Figure 11.268 (A) Anteroposterior view

A

90 degrees of elbow flexion with the forearm pronated. Closed reduction an d pin n in g (with con com itan t arth rogram ) are preferred for older ch ildren an d for th ose fractures with sign ifican t displacem en t.

T-condylar Fractures of the Distal Humerus T-condylar fractures are rare in children and predom inantly affect older adolescen ts. Th ey usually occur by th e sam e hyperexten sion m ech an ism th at causes supracon dylar fractures but with h igh er en ergy. It h as also been postulated th at a fall directly on th e elbow causes th e olecran on to act as wedge, splitting the trochlea. If the fracture is nondisplaced, the fracture can be treated sim ilar to a supracondylar fracture. If th ere is in traarticular displacem en t of greater th an 2 to 3 m m , th en open reduction is required. In youn ger ch ildren , K-wires can be used to h old th e con dylar fragm en ts to each oth er an d to th e h um eral sh aft. In adolescen ts, rigid in tern al fixation usin g bicolum n platin g or 90 –90 plating is essential to allow early m otion (Fig. 11.269). Surgical exposure can be ach ieved from a posterom edial (Bryan – Morrey) approach , olecran on osteotomy, or triceps splittin g tech n ique. Sin ce in traarticular com m in ution is rare in adolescen ts, an olecran on osteotomy is rarely n eeded to an atom ically reduce th e articular surface. Both uln ar an d radial nerve injures have been associated with T-condylar fractures. During surgical exposure, the ulnar should be iden tified an d tran sposed. Olecranon Fractures Fractures of th e olecran on are relatively un com m on an d can occur at any age. The m ech anism of injury is either a fall directly on th e olecran on or avulsion in jury from triceps

B

of a distal humeral physeal fracture. Note that the proximal radius and ulna are displaced medially as a unit. (B) Normal elbow for comparison. (Reproduced with permission from Beaty JH, Kasser JR. Rockwood and Wilkins’ Fractures in Children. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

pull. Metaphyseal fractures are usually m in im ally displaced and can be treated with im m obilization in a long arm cast for 3 to 6 weeks. Radiographs should be obtain ed after 5 to 7 days to be sure th at th ere h as n ot been any displacem en t of th e proxim al fragm en t. If th ere is m ore th an 3 m m of intraarticular displacem ent or gapping of the fracture with elbow flexion , th en open reduction an d in tern al fixation is in dicated (Fig. 11.270). Sim ilar to th e treatm ent in adults, fixation in children is achieved with a tension band construct. Contrary to adults, in whom stainless steel wire is recom m en ded, eith er absorbable or n on absorbable suture can be used for th e ten sion ban d in ch ildren . Th is reduces irritation from h ardware an d avoids th e n eed for later wire rem oval. Apophyseal fracture separation is less com m on than m etaphyseal fracture, although it occurs through a sim ilar m echan ism . Diagnosis can som etim es be difficult because th e secon dary ossification cen ter of th e olecran on is often irregular and som etim es bipartite; radiographs of the contralateral elbow are often extrem ely useful to distinguish between a fracture an d n orm al ossification . Most apophyseal fractures can be treated nonoperatively, although operative treatm ent m ay be indicated for persistent pain or wide displacem en t. Of n ote, apophyseal fractures of th e olecran on have been classically associated with th e diagn osis of osteogen esis imperfecta.

Fractures of the Proximal Radius Fractures of th e upper en d of th e radius accoun t for approxim ately 10% of fractures about th e elbow. Most of these fractures in volve the m etaphyseal neck or the physis and usually occur in children between 8 and 12 years of age. In traarticular in jury is rare; h owever, th ese fractures

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A

B

Figure 11.269 (A) T-condylar fracture in a 16-year-old

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are often associated with other injuries about th e elbow, including olecranon fractures, m edial epicondyle fractures an d elbow dislocations. Mechanism of injury involves a fall on an outstretch ed h an d with a valgus stress to th e elbow. Diagn osis can be difficult in th e youn ger patien t with a m ore cartilaginous epiphysis. In these cases, ultrasound, MRI, or arth rography m ay be required to define the injury. Treatm ent is dictated by the am ount of displacem en t and

boy. Note the intraarticular split and the dissociation of the shaft from the metaphysic. (B and C) Anteroposterior and lateral radiographs after open reduction of the articular surface and internal fixation with 90–90 plates. (Reproduced with permission from Beaty JH, Kasser JR. Rockwood and Wilkins’ Fractures in Children. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

an gulation . In gen eral, reduction is acceptable wh en th ere is less th an 4 m m of tran slation an d less th an 30 degrees of an gulation . Fractures with greater displacem en t or an gulation sh ould be treated in a stepwise fash ion , startin g with the least invasive tech niques before m oving to m ore aggressive m odalities. The reason for this treatm ent progression is th at m ore aggressive treatm ent (i.e., open reduction) is associated with h igh er rates of postoperative stiffn ess,

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sh ould open reduction be attempted. After perform ing a standard lateral approach to the elbow, the fracture should be reduced with care taken to preserve th e an n ular ligam en t and other soft tissue attachm ents. If needed, an oblique Kwire can be placed an terograde th rough th e h ead an d in to th e m etaphysis. Tran scapitellar pin placem en t is associated with an un acceptable rate of pin breakage. Un like adults, excision of th e radial h ead is n ever in dicated in ch ildren . Th e m ost importan t complication s associated with th e treatm ent of radial neck fractures are osteonecrosis an d loss of m otion , particularly in pron ation an d supin ation . Com plication s are m ost com m on after open reduction , but it is difficult to say wh eth er th is is due to th e m ore aggressive treatm ent m ethod or the severity of the in itial injury.

Forearm and Wrist Injuries Figure 11.270 (A) Lateral radiograph demonstrating an internal

tension band technique using axial wires plus absorbable suture for a displaced olecranon fracture. (Reproduced with permission from Beaty JH, Kasser JR. Rockwood and Wilkins’ Fractures in Children. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

osteon ecrosis, an d n on un ion com pared with closed or percutan eous m eth ods. Closed reduction usin g th e Israeli tech n ique of flexion , pron ation , an d direct pressure on the radial h ead or th e Patterson techn ique of extension, varus, and direct pressure should be attempted first. If closed reduction is unsuccessful, percutan eous reduction with a K-wire or a Freer elevator sh ould be attempted (Fig. 11.271). Care should be taken to note the location of the PIN n erve to m in im ize th e risk of in adverten t in jury. Recently, Metaizeau has described th e use of a titanium elastic nail in serted through the distal radius to “catch’’th e radial head an d rotate it into a better position. Only after all attempts at closed an d percutan eous reduction h ave failed

Monteggia Fracture–Dislocations Monteggia fracture–dislocations refer to a fracture of th e proxim al ulna with an associated dislocation of the radiocapitellar joint. The direction of th e radial head dislocation gen erally follows th e apex of th e uln ar fracture an d form s th e basis of th e Bado classification (Fig. 11.272). Diagn osis can often be subtle, an d for th is reason , m any Mon teggia fractures are m istakenly diagnosed as simple ulna fractures. In the norm al forearm , a lin e drawn alon g the axis of the radius sh ould bisect th e capitellum on every radiograph ic view (Fig. 11.273). It is, therefore, imperative that elbow radiograph s be obtain ed in all cases of forearm fractures so th at th is relation sh ip can be adequately assessed. If this relation sh ip is violated in th e settin g of an uln a fracture, then a Monteggia injury is present. As a general principle, it is the alignm ent an d stability of th e uln ar fracture reduction th at dictates th e stability of th e radial h ead reduction . Th erefore, treatm en t of Mon teggia in juries is guided by th e uln ar fracture pattern . Plastic deform ation of th e uln a an d in complete (green stick) fractures are treated with closed reduction and long arm cast

A,B Figure 11.271 (A) Displaced radial neck fracture in an 11-year-old girl. (B) Percutaneous reduction

with a K-wire. (C) Final image showing near-anatomic reduction. (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

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Type I

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Type II

A

B

Type III

Type IV

Figure 11.272 Bado classification. (A) Type I:

apex anterior ulna fracture with anterior dislocation of the radial head. (B) Type II: apex posterior ulna fracture with posterior dislocation of the radial head. (C) Type III: apex lateral ulna fracture and lateral dislocation of the radial head. (D) Type IV: fracture of both the ulna and radius with anterior dislocation of the radial head. (Reproduced with permission from Beaty JH, Kasser JR. Rockwood and Wilkins’ Fractures in Children. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

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im m obilization. The forearm is usually supinated and the elbow flexed 90 degrees (alth ough elbow exten sion m ay be n ecessary for Bado type II fracture pattern s). Complete transverse or short oblique fractures of the uln a are usually treated by closed reduction and intram edullary n ail fixation. Lon g oblique fractures or com m inuted injuries are

D

best treated with open reduction an d plate fixation . Regardless of treatm en t m ethod, it is importan t that th ese fractures be followed closely to prevent loss of radial head reduction . Ch ronic Mon teggia fracture–dislocation s result from m issed diagnosis or loss of reduction after treatm en t. In late cases, the ulna m ay h ave rem odeled sign ificantly so th at th e on ly apparen t in jury is an “isolated’’ radial h ead dislocation . Norm ally, th e posterior border of th e uln a sh ould be com pletely straight. Usually, careful review of th e forearm radiograph s will dem on strate subtle bowin g of th e posterior uln ar border in dicatin g th e site of th e origin al fracture (Fig. 11.274). An addition al ch allen ge is

A

B Figure 11.274 Monteggia injury. (A) A 10-year-old boy with a Figure 11.273 A line drawn down the long axis of the radius

should bisect the capitellum in any view. (Reproduced with permission from Beaty JH, Kasser JR. Rockwood and Wilkins’ Fractures in Children. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

radial head dislocation and a plastically deformed ulna (note the anterior bow of the ulna demonstrated by a line drawn along its subcutaneous border). (B) Contralateral, uninjured arm. Note the straight subcutaneous border. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

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Figure 11.275 Lateral radiograph of a congenital radial head

dislocation. Note the dysplastic shape of the radial head. (Reproduced with permission from Beaty JH, Kasser JR. Rockwood and Wilkins’ Fractures in Children. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

distin guish in g a ch ron ic Mon teggia in jury (with rem odeled uln a) from a con gen ital radial h ead dislocation . Un like th e radial head in Monteggia injuries, the congenitally dislocated radial head is sm all, convex, and usually associated with a hypoplastic capitellum (Fig. 11.275). Treatm en t of ch ron ic Mon teggia in juries is ch allen gin g an d often n ecessitates shortening ulnar osteotomy, open reduction of th e radiocapitellar joint, and an nular ligam en t reconstruction. Loss of pronation after this late reconstruction should be expected.

Diaphyseal Fractures Diaphyseal forearm fractures are divided in to th ree categories based on fracture pattern : plastic deform ation , green stick, an d complete fractures. Plastic deform ation results wh en the forces applied to th e young child’s forearm exceed th e elastic lim it of bon e but fall sh ort of its ultim ate stren gth. Excessive plastic deform ation (usually > 20 degrees of an gulation ) can lim it forearm rotation , so closed reduction is in dicated for any of th ese in juries. Reduction is obtain ed by applyin g a sustain ed th ree-poin t load over the apex of th e deform ity until the deform ity gradually improves (usually un der gen eral an esth esia), an d th e arm is im m obilized in a well-m olded lon g arm cast. Green stick fractures are in complete fractures and usually have both angular an d rotation al displacem en t. Most of th ese fractures can also be treated with closed reduction and placem ent of a well-m olded long arm cast. Reduction m ust correct both componen ts of the deform ity and is perform ed according to th e “rule of th um bs.’’ In th is m an euver, th e th um b is

rotated toward th e apex of th e deform ity as th e an gulation is corrected. For example, to reduce an apex dorsal fracture, th e wrist is supin ated an d a volarly directed force is applied at the fracture site. Complete fractures occur in older ch ildren an d by definition are m ore inh erently unstable. Cast im m obilization (with a proper m old) is indicated for those patien ts wh o can ach ieve an d m ain tain an adequate reduction . In gen eral, 20 degrees of an gulation an d bayon et apposition can be accepted in ch ildren youn ger th an 8 years. No m ore th an 10 degrees of an gulation sh ould be accepted in ch ildren older th an 10 years. Alth ough it h as been suggested th at 30 degrees of rotation al m alalign m en t can be tolerated, it is important to rem em ber that m alrotation does not rem odel an d sh ould be corrected wh en ever possible. Operative treatm ent is indicated for un stable fractures, unacceptable align m ent, refractures, and neurovascular or soft tissue com prom ise. In youn ger patien ts, in tram edullary n ail fixation (with a K-wire or titanium elastic nail) is the preferred treatm ent m eth od (Fig. 11.276). Since these devices do not con trol rotation , postoperative cast im m obilization is n ecessary. Patien ts with com m in uted fractures or less th an 1 year of skeletal growth rem aining can be treated sim ilar to adults with open reduction and plate fixation.

Distal Radius Fractures Approxim ately 75% of all forearm fractures involve the distal radius, an d th e location of th e in jury can be eith er m etaphyseal or physeal. Metaphyseal fractures of the distal radius in clude buckle (torus) fractures an d bicortical fractures. Buckle fractures are inherently stable because the cortex fails in compression, an d simple im m obilization in a splin t or sh ort arm cast for 3 weeks is sufficien t treatm en t. Bicortical fractures are gen erally treated with cast im m obilization after closed reduction of th e fracture (if necessary) (Fig. 11.277). Because of the proxim ity of these fractures to the distal radial physis, a trem endous am ount of rem odeling potential exists, an d therefore, substantial residual angulation and displacem ent can be accepted. Gen erally, 20 to 25 degrees of an gulation in th e sagittal plan e is acceptable in children younger than 12 years. Approxim ately 10 to 15 degrees of sagittal an gulation can be accepted in older patien ts. Alth ough two ran dom ized con trolled trials support th e use of sh ort arm casts alon e, m ost orth opaedic surgeons still use lon g arm casts for 3 weeks followed by sh ort arm casts un til healing. Surgical indications include irreducible or unstable fractures, open fractures, neurovascular injuries, and excessive soft tissue swelling. The m ost com m on technique is percutaneous pinning with one or two sm ooth pins; plate fixation has lim ited indications prim arily in older patien ts. Distal radial physeal fractures are usually Salter–Harris type I or II injuries and are treated in a sim ilar fashion as m etaphyseal fractures. Reduction m aneuvers should be perform ed gen tly un der adequate sedation to m in im ize un due traum a to th e physis. Multiple attempts at reduction


A

B Figure 11.276 A 12 year-old girl with complete midshaft forearm fracture. (A) AP and lateral injury

radiographs demonstrating marked displacement of both the radius and ulna. (B) Post operative AP and Lateral films demonstrating reduction of both bones and fixation with titanium elastic nails. (Reproduced with permission from Beaty JH, Kasser JR. Rockwood and Wilkins’ Fractures in Children. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

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A

B

Figure 11.277 (A) Lateral radiograph of a dis-

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sh ould be avoided, as this can increase the risk of a growth arrest. For th e sam e reason s, m an ipulation sh ould n ot be attempted after 7 to 10 days. Overall, th e in ciden ce of growth arrest after distal radial physeal fracture h as been reported to be rough ly 4%. Sim ilar to m etaphyseal fractures, operative in terven tion usually con sists of percutaneous pinning and is indicated for un stable in juries, neurovascular comprom ise, an d severe soft tissue swellin g.

placed metaphyseal fracture at the time of initial casting. (B) Early healing of the fracture with significant displacement. (C) Seven months later, the fracture has completely remodeled. (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

tion typically is out of the plane of the m otion of the joint (usually m edial or lateral), rem odeling is m inim al at best. Th erefore, reduction of th ese in juries is essen tial; on ce reduced, th ey are usually stable with sim ple buddy tapin g to th e adjacen t digit with a sm all splin t. Adolescen ts wh o sustain m etacarpal fractures an d fractures of th e th um b as a result of aggressive beh avior sh ould be m an aged in a m an n er sim ilar to th eir adult coun terparts.

Hand Injuries Most m etacarpal an d ph alan geal fractures in ch ildren are nondisplaced and require m in im al treatm ent. The m ajority of displaced fractures can be adequately reduced closed an d im m obilized, usin g simple splin ts or casts. It is im portan t to im m obilize fin gers in th e position of fun ction to preven t un n ecessary stiffn ess. As is so often th e case, when the vast m ajority of in juries are benign, it is easy to overlook th e problem h an d an d fin ger fractures. Th erefore, several specific in juries are worthy of note. Condylar fractures, especially if in traarticular (in eith er th e m iddle or proxim al ph alan x), require an atom ic reduction an d fixation . As in adults, degen erative ch an ges an d deform ity will result if th ey are n ot treated appropriately. Physeal fractures occur typically at th e base of th e proxim al ph alan x; th ese are usually Salter–Harris type II injuries. Because an gula-

PELVIC FRACTURES Th e pelvis in a ch ild is far m ore flexible th an th at of th e adult. Because of the presence of significantly m ore cartilage, the pediatric pelvis is able to absorb m ore en ergy prior to failure. Un fortun ately, th e abdom in al con ten ts are n ot n ecessarily as pliable; thus, with th e relative lack of protection provided by the im m ature pelvis, they are m ore likely to be dam aged. Alth ough associated gen itourin ary in juries an d h ead traum a are com m on, the m ortality of pelvic fractures is on ly one-third the rate reported for adults. Pelvic traum a in children is indicative of a high energy injury an d prim arily results from pedestrian versus m otor veh icle accidents. Lower energy avulsion in juries can be secondary to ath letic traum a.


In itial evaluation of ch ildren with pelvic traum a follows standard traum a protocols (see th e section on “Pediatric Polytraum a’’), with the first priority being securin g the airway an d ensuring hem odynam ic stability. Given th e association with oth er in juries, it is im perative th at all m ajor organ system s are th orough ly ch ecked for th e presen ce of injury. Workup for the pelvic fracture includes a rectal exam ination an d inspection of the perineum to rule out an open in jury, as well as proper im agin g (eith er in let/ outlet views or CT scan ) to define the fracture pattern. Pediatric pelvic fractures are classified in a m anner sim ilar to adult pelvic fractures. One m ajor differen ce, however, is th at children can experien ce a sin gle break to the pelvic rin g. Avulsion in juries are treated n on surgically with rest, activity m odification, rehabilitation , and protected weight bearin g. More sign ifican t pelvic fractures are still treated nonoperatively unless th ey are sign ificantly unstable. In th ese rare cases, extern al fixation or open reduction an d internal fixation with reconstruction plates m ay be indicated. Unique to th is age group is dam age to th e open triradiate cartilage. Sh ould th is occur, th e n orm al h eigh t an d depth of th e acetabulum m ay n ot be ach ieved. Prem ature closure

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of th is physis could result in acetabular dysplasia an d progressive h ip subluxation . Late osteotom ies of th e pelvis are usually required to treat th is un fortun ate com plication .

LOWER EXTREMITY Fractures of the Hip and Thigh Hip Fractures Un like osteoporotic h ip fractures in the elderly, wh ich result from relatively low loads, hip fractures in children are n early always th e result of h igh -en ergy traum a. Mech anism of in jury is usually a m otor veh icle acciden t or fall from h eigh t, an d associated in juries in clude h ead traum a, long bon e fractures, an d visceral in juries. Th e h igh -en ergy n ature of these injuries can jeopardize the vascular anatomy of th e h ip in th e growin g ch ild, leadin g to avascular n ecrosis (AVN) of th e fem oral head. Urgent anatom ic reduction and stabilization is necessary to restore blood flow to the fem oral head and decompress the fracture h em atom a. Pediatric hip fractures are classified according the system of Delbet (Fig. 11.278). Type I fractures are tran sphyseal an d are, th erefore, sim ilar to an acute slipped capital

A

B

Figure 11.278 Delbet classification for prox-

imal femur fractures. (A) Type I is transepiphyseal. (B) Type II is a transcervical fracture. (C) Type III is a basicervical fracture. (D) Type IV is an intertrochanteric fracture. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

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D

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fem oral epiphysis. These fractures are rare, accounting for less th an 10% of all h ip fractures. Un fortun ately, th ey also have the highest rate of AVN, at nearly 90%. As a result, it is imperative th at type I fractures be reduced an d stabilized in an em ergen t fash ion . O n ly on e or two attempts sh ould be m ade to gen tly close reduce th is fracture, as repeated attempts can in crease th e risk of osteon ecrosis an d prem ature physeal closure. If th e fracture can n ot be reduced closed, or if th ere is any question about th e adequacy of th e reduction , th e fracture site sh ould be exposed th rough an an terior approach to directly visualize th e reduction . To obtain stable fixation , m ultiple sm ooth pin s sh ould be used to cross the physis. It is the general consensus that th e stability of reduction supercedes th e preservation of th e physis, sin ce AVN is a m uch m ore difficult complication to treat th an a leg length discrepancy. Ch ildren youn ger than 10 years sh ould be protected in a spica cast postoperatively. Delbet type II fractures are tran scervical with th e fracture lin e run n in g across th e m iddle of th e fem oral n eck. Th e risk of AVN from th ese in juries is rough ly 50%. Type III fractures are basicervical an d h ave a lower rate of AVN, reported between 20% an d 30%. For n on displaced fractures an d th ose fractures in wh ich an an atom ic reduction can be achieved closed, percutaneous fixation can be used. If sufficien t bon e exists between th e fracture an d th e physis, can nulated screws or threaded pins can be used to achieve fixation (Fig. 11.279). If th e physis m ust be crossed, sm ooth

A

B Figure 11.279 (A) Approximately 5-year-old boy with a type III

femoral neck fracture. (B) Three months after anatomic open reduction and internal fixation with two screws sparing the physis. (Reproduced with permission from Beaty JH, Kasser JR. Rockwood and Wilkins’ Fractures in Children. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

pin s sh ould be used to m in im ize th e risk of growth arrest. Sim ilar to type I fractures, on e sh ould h ave a low th resh old to open th e fracture site if th ere is any question as to th e adequacy of the reduction. In younger patien ts, a spica cast is generally used to protect the reduction after surgery. Delbet type IV in juries are in tertroch an teric fractures. Sin ce th ey are extracapsular, th e blood supply to th e fem oral head is rarely disrupted, an d these fractures have the lowest rate of AVN (10%). Children younger than 6 years can usually be treated with closed reduction and spica casting. In older children and in those younger children with un stable fractures, percutan eous fixation with screws or pin s sh ould also be used. Again , h ardware sh ould be left short of the physis to m inim ize the risk of a growth arrest. Open reduction should be perform ed when ever the fracture cann ot be reduced anatom ically through closed m eans. In older ch ildren or adolescents, a screw and side plate or blade plate can be used for fixation . Th ese tech n iques obviate th e n eed for a postoperative spica cast. As previously m en tioned, the m ost devastating complication of pediatric hip fractures is osteon ecrosis. AVN usually develops within 6 m onths, although it can be seen as late as 2 years after the initial injury (Fig. 11.280). Early treatm ent consists of protected weight bearing. After collapse, proxim al fem oral osteotom ies can be used to rotate intact portions of th e fem oral head into the weight-bearing zon e. An oth er com plication of h ip fractures is varus deform ity (coxa vara) eith er from m alunion or growth disturban ce; th e in ciden ce of th is h as been reported between 20% an d 30%. Coxa vara is best preven ted by obtain in g an anatom ic reduction at the tim e of surgery with rigid fixation . Severe deform ities m ay require a subtroch an teric valgus producing osteotomy. Nonunion s occur m ost often with displaced type II fractures an d can be seen in 5% to 10% of h ip fractures overall. Treatm en t usually con sists of valgus intertrochanteric osteotomy with bone grafting. Prem ature physeal arrest usually occurs in type I fractures or oth er fractures in wh ich h ardware was placed across th e growth plate. Th e in ciden ce of growth arrest h as been reported anywh ere between 5% an d 65% in th e literature; if the arrest results in a sign ifican t leg length discrepancy, a contralateral epiphysiodesis m ay be indicated.

Diaphyseal Femur Fractures Fractures of th e fem oral sh aft con stitute approxim ately 2% of ch ildh ood fractures. In ch ildren youn ger th an 1 year, wh o are n ot yet walkin g, fem ur fractures sh ould be th orough ly worked up for th e possibility of ch ild abuse. However, after th e walkin g age, fem ur fractures are n ot un com m on and can result from m otor veh icle accidents, falls from h eigh t, an d sports in juries. Th e rem odelin g poten tial for fem ur fractures is greatest in ch ildren younger than 10 years, fractures close to the ph ysis, an d m alalignm ents in the plan e of joint m otion . As a general guidelin e, in children younger than 10 years, up to 15 degrees of coron al plan e an gulation , 20 degrees of


A

425

B

Figure 11.280 (A) Anteroposterior radiograph taken 6 months after screw implantation. (B) Another radiograph taken after screw removal at 18 months shows avascular necrosis of the femoral head. (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

sagittal plane angulation, and 30 degrees of m alrotation can be accepted. Overgrowth of the involved fem ur is com m on an d should be discussed with the fam ily. In children between th e ages of 2 an d 10 years, th e overgrowth averages 0.9 cm . As a result, shortening in children of th is age group of 1.5 to 2.0 cm at un ion can be accepted. In older ch ildren , with less potential for overgrowth, no m ore than 1 cm of sh orten in g is recom m en ded. Based on improved surgical tech niques an d a better un derstan din g of th e social im pact of prolon ged im m obilization in children, there has been a recent trend toward m ore operative treatm en t for pediatric fem ur fractures. Th e specific choice of treatm ent, h owever, depends on the age an d size of th e patient as well as the fracture pattern. In children younger than 1 year, a Pavlik h arn ess or soft roll spica cast can be used to im m obilize th e child. Healing is rapid an d im m obilization can usually be discontinued by 4 weeks. For ch ildren between th e ages of 1 an d 6 years, early spica casting is preferred for all but the m ost unstable fractures. Th ere are recen t reports of compartm en t syn drom es as a result of excessive traction durin g spica cast application . It is currently recom m en ded th at a long leg cast be rolled first with care taken n ot to apply excessive force to th e posterior calf or popliteal area. After ensuring a proper valgus m old, the rest of the cast can be extended up to th e nipple line. For those high-energy injuries with unstable fracture patterns, a period of skeletal traction m ay be necessary prior to th e spica cast to preven t unacceptable sh orten ing. Multiple treatm en t option s exist for th e sch ool-aged ch ild with open physes. As previously m entioned, there has

been an evolvin g tren d toward operative treatm en t in th is age group, as it allows earlier m obilization an d m in im izes the social impact of prolonged im m obilization. Flexible in tram edullary n ailin g is th e treatm en t of ch oice for m ost diaphyseal fractures in the sch ool-aged child (Fig. 11.281). Flexible n ails provide load-sh arin g fixation th at allows for sufficien t m otion at th e fracture site to generate abundan t callus. The inciden ce of m alunion an d refracture are rare; the m ost com m on complication is soft tissue irritation at the nail entry site. For very proxim al or distal fractures, com m in uted fractures, or other patterns that are “lengthun stable,’’extern al fixators h ave m any advan tages over flexible n ails. Ben efits of extern al fixation in clude rapid application , ability to achieve length and alignm ent, m inim al blood loss, an d low risk of physeal dam age or osteon ecrosis. Com plication s include pin-site irritation, knee stiffn ess, delayed un ion , an d an in creased risk of refracture after fixator rem oval. An altern ative treatm en t option for th e proxim al, distal, an d len gth -un stable fractures is plate fixation . Subm uscular tech n iques allow plates to be placed th rough percutan eous in cision s with less soft tissue strippin g an d n o n eed for postoperative im m obilization . Older adolescents with closed physes can be treated in a m anner sim ilar to that in adults. Usually this consists of a rigid, ream ed in tram edullary n ail. Advan tages in clude rapid m obilization, a predictably high union rate, and a low risk of m alalign m en t. Rigid in tram edullary n ails are n ot advised in the skeletally im m ature because of th e risk of fem oral h ead AVN. Insertion through the piriform is fossa can disrupt th e lateral ascending branch es of the m edial

426


A

B

C

D

Figure 11.281 (A and B) Injury radiographs demonstrating a short oblique femoral shaft fracture

in an 8-year-old boy. (C and D) Anteroposterior and lateral radiographs 4 months after treatment with flexible intramedullary nails. Note the abundant callus at the fracture site. (Reproduced with permission from Skaggs DL, Tolo VT. Master Techniques in Orthopaedic Surgery: Pediatrics. Philadelphia, PA: Lippincott Williams & Wilkins, 2008.)


Safe starting point for pediatric antegrade nail

427

Lateral epiphyseal a. Lateral femoral circumflex a. Ligamentum teres a. Growth plate

Medial circumflex a.

ANTERIOR

Femoral a.

POSTERIOR

Figure 11.282 Blood supply of the proximal femur. Note

the safe entry site for an antegrade nail. (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

circum flex artery comprom ising th e circulation of the fem oral epiphysis (Fig. 11.282). While trochanteric entry nails m ay have a lower risk of osteonecrosis, growth disturban ces of th e proxim al fem ur h ave been reported.

Fractures About the Knee Distal Femoral Physeal Fractures Fractures th rough th e distal fem oral physis do n ot h ave a un ique classification an d are usually described by th e Salter–Harris classification. The distal fem oral physis is not plan ar but h as a complex un dulatin g sh ape th at actually m atches four m am m illary processes in th e distal fem oral m etaphysis; this arran gem en t provides som e resistance to sh ear. Un fortunately, when a fracture does occur, this configuration reduces th e odds of a clean cleavage plan e an d increases the risk of partial or complete physeal arrest. Th e diagn osis is usually eviden t based on swellin g about th e knee an d plain radiographs. In m ore subtle cases, it is im portan t to rem em ber th at in patien ts with open growth plates, physeal in juries are m ore likely th an ligam en tous injuries. In these cases, stress radiographs are often h elpful to diagn ose n on displaced fractures. Th e goal of treatm en t sh ould be an atom ic reduction . Non displaced fractures an d th ose fractures th at are stable after closed reduction can be treated with im m obilization in a long leg cast. For fractures that do not reduce easily an d un stable fractures, closed or open reduction with per-

Lateral femoral circumflex a. ANTERIOR

cutan eous fixation (followed by castin g) is the preferred form of treatm ent. Crossed sm ooth pin s can be inserted either retrograde or anterograde. While retrograde in sertion is tech n ically easier, an terograde pin placem en t allows on e to keep th e h ardware out of th e join t, th ereby reducin g the risk of intraarticular sepsis. Salter–Harris type II fractures with large Th urston –Holland fragm ents can be stabilized with can n ulated screws placed across th e m etaphyseal spike (Fig. 11.283). Salter–Harris type III an d IV fractures can be treated with screws placed across the epiphysis. In spite of proper treatm en t, 50% of distal fem oral physeal fractures will develop a partial or complete growth arrest. Th ese arrests can rapidly result in sign ifican t deform ities sin ce th e distal fem oral physis is th e m ost active physis in body, gen erating rough ly 0.9 cm /yr of growth. If there is any suspicion of physeal dam age, MRI is indicated to evaluate th e h ealth of th e growth plate. Depen din g on the n ature an d location of the arrest, options in clude bar resection , completion of th e epiphysiodesis, con tralateral epiphysiodesis, or corrective osteotom y (plus len gth en in g if n eeded).

Tibial Eminence Fractures Tibial em in en ce fractures are th e pediatric equivalen t of an anterior cruciate ligam ent (ACL) injury as it is the site of the ACL insertion. The injury typically occurs in children aged 8 to 12 years and is usually th e result of a hyperexten sion load. Not surprisingly, m ost of th ese result from athletic

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A

B

C

D Figure 11.283 (A and B) AP and lateral radiographs of a 13-year-old boy with a Salter–Harris type

II distal femoral physeal fracture. Note the size of the Thurston–Holland fragment. (C and D) Intraoperative radiographs after reduction and fixation with a 7.3-mm cannulated screw. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

traum a. Meyers an d McKeever classified th ese fractures in to type I (n on displaced), type II (an terior elevation with an in tact posterior h in ge), an d type III (completely displaced) (Fig. 11.284). Type I in juries can be treated closed with 6 weeks of cast im m obilization. An attempt can be m ade to reduce type II in juries by exten din g th e kn ee, followed by im m obilization for 6 weeks. Irreducible type II in juries an d all type III fractures require open or arth roscopic reduction an d fixation . Fixation can be ach ieved by an epiphyseal screw or by passing sutures th rough the base of th e ACL an d tyin g over th e fron t of th e tibia. Stable fixation an d early m obilization can reduce th e risk of arth rofibrosis.

Tibial Tubercle Avulsions Tibial tubercle avulsion s occur th rough th e physis of th e tubercle an d m ost often occur in ch ildren wh o are n earin g skeletal m aturity. Most injuries are due to the eccen tric

A

B

C

Figure 11.284 Classification of tibial spine fractures. (A) Type

I—minimal displacement. (B) Type II—hinged posteriorly. (C) Type III—completely displaced. (Reproduced with permission from Beaty JH, Kasser JR. Rockwood and Wilkins’ Fractures in Children. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)


A

B

429

C

Figure 11.285 Classification of tibial tuberosity fractures. (A) Type I fracture through the sec-

ondary ossification center. (B) Type II fracture located at the junction of the primary and secondary ossification centers. (C) Type III fracture is an intraarticular fracture (Salter–Harris type III). (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

loading of the quadriceps durin g jumping or lan ding. Ogden has classified th ese fractures into three types: type I is a sm all avulsion of th e distal part of the tubercle, type II is a larger avulsion up to th e tran sverse level of th e tibial epiphysis, an d type III is a com plete avulsion th at exten ds through th e epiphysis and into the joint (Fig. 11.285). Sm all, n on displaced fractures can be treated by castin g the leg in extension. Displaced type I fractures can be fixed with suture weaved th rough th e patellar ten don an d tied over a post. Type II and III fractures usually require open reduction an d screw fixation in to th e m etaphysis. Sin ce m ost fractures occur in ch ildren with closin g physes, growth disturban ce is rare followin g tibial tubercle avulsions. In those rare in juries in patien ts younger th an 11 years, genu recurvatum can occur.

Proximal Tibial Fractures Proxim al tibial physeal fractures are sim ilar to growth plate injuries of the distal fem ur. The m echanism is m ost often the result of force applied to the planted leg. This fracture has been described as th e pediatric equivalent of a kn ee dislocation , an d n eurovascular in jury h as been reported in up to 10% of th ese fractures, especially th ose with an apex posterior an gulation . As a result, careful assessm en t for vascular insufficiency and compartm ent syn drom e is m andatory in th ese injuries (Fig. 11.286). Nondisplaced fractures can be treated in a long leg cast. Unstable fractures are best treated with CRPP. As with distal fem oral physeal injuries, approxim ately 40% of these fractures are complicated by partial or complete growth arrest.

Proxim al tibial m etaphyseal fractures usually presen t in ch ildren between 2 an d 10 years of age. Th ese fractures often appear relatively ben ign , with on ly a m in im al gap on the m edial side of the proxim al tibial m etaphysis. Treatm en t con sists of closed reduction with varus stress, followed by im m obilization in a lon g leg cast for at least 6 weeks. Occasionally, soft tissue can be interposed in th is gap an d can preven t an atom ic reduction ; in th ese cases, open exploration an d reduction is in dicated. In spite of an adequate reduction , paren ts sh ould be warn ed th at these fractures can develop a late valgus deform ity (usually within 12 –18 m on th s). Most authors believe that this results from asym m etrical growth after fracture healing. The vast m ajority of th ese m alalign m en ts will spon tan eously correct within 3 years of th e injury. As a result, corrective osteotomy is usually n ot n ecessary. Prem ature osteotom ies are often complicated by recurren t deform ity.

Leg and Ankle Injuries Tibial Diaphyseal Fractures Tibial sh aft fractures are th e m ost com m on lower extrem ity fractures in children, accounting for 5% of all pediatric fractures. The m ost likely m echanism of injury depen ds on the age of the patient. In children between 1 and 6 years of age, fractures usually result from torsional stresses on the tibia th at occur durin g run n in g, jum pin g, an d oth er seem in gly innocuous activities. These in juries h ave been term ed toddler fractures and are frequently so subtle that radiographs m ay be interpreted as norm al (Fig. 11.287). Oblique radiograph s an d bon e scan s can h elp to iden tify occult fractures.

Figure 11.286 Posterior displacement from a proxi-

mal tibial physeal fracture can cause arterial injury. (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

A

B Figure 11.287 (A and B) Toddler fractures are often difficult to appreciate on a single radiographic view. The lateral view demonstrates the spiral fracture. (Reproduced with permission from Skaggs DL, Flynn JM. Staying Out of Trouble in Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)


However, diagn osis can usually be m ade on the basis of a careful physical exam in ation , wh ich dem on strates localized tendern ess over the shaft of the tibia. In older adolescen ts, the m echanism of injury is m ore often m otor vehicle accidents, falls from height, or athletic traum a. Standard radiograph s in th ese patien ts are usually diagn ostic. Th e m ajority of toddler fractures can be treated con servatively. These fractures are usually spiral in nature and nondisplaced because of th e presence of dense, thick periosteum , wh ich h olds its position . Im m obilization in a long leg cast for 3 to 4 weeks is m ore than adequate treatm en t. For older children, the guidelines for acceptable reduction are less th an 10 degrees of coron al or sagittal an gulation an d less than 10 degrees of m alrotation. Un like fem oral fractures, overgrowth in the tibia is quite variable, so m ost authors recom m end that no m ore than 1 cm of sh ortenin g be accepted. As long as th ese criteria are m et, con servative treatm en t is appropriate. Surgery is indicated in cases of open fracture, compartm ent syndrom e, polytraum a, irreducible fracture, and loss of reduction during con servative treatm ent. Flexible intram edullary nails are an excellen t treatm en t ch oice for len gth -stable fractures (tran sverse or short oblique) in th e m iddle third of the tibia. As in the fem ur, flexible nails result in predicable un ion rates with a low risk of complication s. Extern al fixators are an effective tool for restoring length an d alignm ent when com m inution is present or in cases of very distal or proxim al fractures. External fixation is also the treatm ent of ch oice for severe open fractures or significant soft tissue injury.

Ankle Fractures Pediatric ankle fractures are relatively com m on injuries, an d usually affect children between 8 an d 15 years of age. Th e m ech an ism of in jury is usually in direct traum a from a twisting injury although direct traum a from m otor veh icle accidents, falls, or contact sports can be respon sible. Proper evaluation in cludes AP, lateral, an d m ortise radiograph s of the in volved extrem ity. The m ortise view, in particular, is important as som e pediatric physeal fractures cann ot be readily visualized on stan dard AP an d lateral radiograph s. Accessory ossification centers including th e os subtibiale, os subfibulare, an d os trigon um are com m on an d can often be con fused with acute fractures. Careful physical exam in ation, radiographs of th e contralateral extrem ity, and a bone scan (if n ecessary) can distinguish these anatom ic varian ts from acute injuries. ACT scan is useful in cases of suspected intraarticular in jury. In these in stances, plain radiographs often un derestim ate th e degree of displacem en t, an d CT scans can be invaluable for determ in in g the need for an d exten t of surgery. Most in juries are physeal an d can be classified accordin g to th e Salter–Harris system . Salter–Harris type I fractures of the distal tibia or fibula are often m isdiagn osed as ankle sprain s since there can be m inim al or no displacem ent at the fracture site. It is important to rem em ber that in chil-

431

dren , th e physis is weaker th an th e surroun din g ligam en ts an d, th erefore, m ore susceptible to in jury. In th e distal tibia, acceptable reduction in ch ildren with m ore th an 2 years of growth rem aining con sists of no m ore than 15 degrees of plan tar tilt in th e sagittal plan e, n o m ore th an 10 degrees of valgus m alalign m en t, an d n o varus. For older adolescents with less growth rem ainin g, acceptable alignm ent is reduced to less than 5 degrees in all plan es. For n ondisplaced fractures of th e distal tibia an d th ose fractures th at can be adequately reduced, treatm ent consists of lon g leg cast im m obilization for 4 weeks, followed by tran sition to a sh ort leg walkin g cast for an addition al 2 weeks. O pen reduction m ay be n ecessary if th ere is in terposed periosteum or soft tissue th at blocks adequate reduction . Isolated Salter–Harris type I fractures of the distal fibula are usually n ondisplaced and can be treated with a short leg walking cast for 3 to 4 weeks. Salter–Harris type II fractures are the m ost com m on distal tibial physeal in juries in ch ildren . Th e criteria for reduction is the sam e as for Salter–Harris type I fractures as is th e treatm en t for n on displaced an d reducible in juries. Wh en n ecessary, operative treatm en t con sists of clearing interposed soft tissue from the fracture site, stabilizin g th e fracture with sm ooth pin s, an d applyin g a lon g leg cast. Because of th eir in traarticular n ature an d th eir propen sity for causing a growth arrest, m ost Salter–Harris type III an d IV fractures of th e distal tibia an d m edial m alleolus require surgery. Ach ievin g an atom ic reduction with adequate stabilization is the best m eans of m inim izing th e risk of growth disturbance. Closed treatm ent can be successful for fractures with m in im al articular displacem en t (2 –3 m m ); h owever, open reduction, includin g an arthrotomy to visualize th e join t surface, is usually n ecessary. Fixation m ost com m only con sists of interfragm entary screws place parallel to th e physis (Fig. 11.288). If n ecessary, sm ooth pin s can be placed across the physis. After healing, routine radiograph s sh ould be taken at 6-m on th in tervals for 2 years after in jury to en sure n orm al growth . Prem ature physeal closure an d an gular deform ity will usually be apparent by th at tim e. Two un ique an kle fractures are seen in th e preadolescent and adolescent age groups. These fractures h ave been referred to as transitional fractures, because they result from the specific an atomy of th e closing physis. Closure of the distal tibial physis begin s at approxim ately 12 in girls an d 13 years in boys an d gen erally takes 18 m on th s to complete. Physeal closure does n ot occur un iform ly but rath er occurs centrally, then m edially, and finally laterally. The anterolateral portion of th e physis is, th erefore, th e last region to close. During this closure period, transition zon es between fused an d unfused areas of th e physis represent areas of relative weakn ess th at are susceptible to fracture. Tillaux fractures are Salter–Harris type III avulsions of the anterolateral epiphysis th at result from pull of th e an terior in ferior tibiofibular ligam en t (Fig. 11.289). As m en tion ed earlier, this is th e last region of the physis to close. Radiographs

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A

B Figure 11.288 (A) Salter–Harris type IV distal tibia fracture in a 12-year-old girl. (B) Anteroposte-

rior radiograph after open reduction and fixation with screws placed parallel to the physis. (Reproduced with permission from Beaty JH, Kasser JR. Rockwood and Wilkins’ Fractures in Children. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

usually m ake th e diagn osis, but CT scan s m ay be n ecessary to elucidate th e full exten t of articular in volvem en t. Sim ilar to oth er Salter–Harris type III in juries, treatm en t con sists of an atom ic reduction of th e articular surface usually with in ternal fixation . Since these in juries occur in patien ts with closing physes, growth disturban ce is n ot a con cern . Triplan e fractures are com plex Salter–Harris type IV fractures th at, as th eir n am e implies, h ave m ultiple plan es of in volvem en t. O n AP an d m ortise views, triplan e fractures appear to be Salter–Harris type III injuries (Fig. 11.290). In th e lateral view, h owever, th e fracture often looks m ore like a Salter–Harris type II injury with a posterior m etaphyseal fragm ent. Because th e fracture is difficult to visualize in th ree dim en sion s, CT scan s with sagittal an d coron al

recon struction s are usually in dicated. Sim ilar to oth er in traarticular fractures, the goal of treatm ent is anatom ic reduction of th e join t surface. An articular step-off of m ore th an 2 m m or fracture gap of m ore th an 2 to 3 m m is an indication for open reduction with an arthrotomy to visualize the articular surface. Fixation usually consists of interfragm entary screws placed across the epiphysis from a lateral to m edial direction and across the m etaphysis from anterior to posterior. Sim ilar to Tillaux injuries, triplan e fractures occur in patients nearin g skeletal m aturity; as a result, th e risk of growth disturban ce is m in im al an d fixation m ay cross th e physis if necessary. Patients should be placed in to a n on –weigh t-bearin g cast for approxim ately 6 weeks.

Figure 11.289 Juvenile Tillaux fracture. (A and B)

A

B

Mechanism of injury is due to avulsion of a fragment of the lateral epiphysis by the anteroinferior tibiofibular ligament. (Reproduced with permission from Beaty JH, Kasser JR. Rockwood and Wilkins’ Fractures in Children. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)


A

433

B

Figure 11.290 Triplane fracture of the distal tibia

C

Foot Fractures Fractures of th e foot in ch ildren are very sim ilar, both in m echanism and m anagem ent, to those in adults. Fractures of th e m etatarsals an d ph alan ges are alm ost ubiquitously m anaged nonoperatively. Excellent results are usually anticipated. On e injury unique in this age group is th e stress fracture of the calcaneus. Frequently, the child who presents with h eel pain is diagn osed with Sever disease. Th is osteoch ondrosis of the calcaneal apophysis is com m on in young ch ildren . However, should the tenderness be m ore distal in the body of the calcan eus an d the symptom s be m ore intense, a stress fracture of the calcan eus should be considered. Abon e scan is usually adequate to m ake th e diagn osis,

in a 12-year-old girl. (A) The anteroposterior radiograph shows a Salter–Harris type III fracture. (B) The lateral radiograph shows an apparent Salter–Harris type II fracture. (C) Computed tomography through the epiphysis helps assess the true displacement of the fracture. (Reproduced with permission from Morrissy RT, Weinstein SL. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

because radiograph s are often n orm al. A sh ort leg cast for 3 to 4 weeks is usually an adequate treatm ent.

Child Abuse Approxim ately 2 m illion ch ildren experien ce ch ild abuse every year. Approxim ately 25% of th ese ch ildren are physically abused, resultin g in m ore than 1,000 deaths per year. Half of th e ch ildren are younger than 2 years, an d 40% are between 2 an d 5 years of age. It is widely recogn ized th at early diagn osis is importan t. Green h as stated th at sh ould an abused child be returned to h is or h er h om e without appropriate in tervention, approxim ately 50% to 70% are

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at risk for furth er in jury, an d 10% are at risk for death . Paren ts (in cludin g th e m oth er) are com m on ly at fault, as are stepfathers and oth er m ale partners of the m oth er wh o are not the biologic fath er. O rth opaedic surgeon s are frequen tly called upon to evaluate m usculoskeletal in juries an d to weigh in on th e likelih ood th at a given fracture resulted from n on acciden tal traum a. Many large pediatric h ospitals h ave dedicated, m ultidisciplin ary “abuse’’ team s th at are respon sible for the evaluation of suspected cases of child abuse. In m any situations, h owever, decisions m ust be m ade by th e treatin g physician , wh eth er it be th e pediatrician , em ergen cy departm en t physician , or th e orth opaedic surgeon . Th e diagn osis rests on th e fin din g of a con stellation of symptom s, th at, wh en viewed collectively, poin t to ch ild abuse. Usually a vague or inconsisten t history is offered by th e caregiver that does n ot explain the ch ild’s injuries. Most ch ildren are with drawn an d an xious wh ile bein g evaluated by a doctor. Assessm ent of the skin for bruises an d burns is essen tial as 60% of physically abused ch ildren h ave on ly soft tissue injuries. Multiple bruises of different colors suggest th at m ultiple in juries h ave occurred at differen t poin ts in tim e. Bruisin g on th e buttocks, trun k, an d back of legs are all h igh ly suspicious for in ten tion al in juries. In addition , bruise pattern s from com m on objects can occur from belt buckles an d coat h an gers an d oth er h ouseh old devices. Multiple, sm all burn s of differen t ages suggest th e use of cigarettes or m atch es to punish the ch ild. Non skeletal traum a is com m on an d sh ould be evaluated by th e appropriate specialists. Retin al h em orrh ages can occur from violent shakin g of sm all infants. Visceral injury can result from an im pact with a th ick object, such as a wall. The m ost com m on in traabdom inal in jury is a liver laceration ; h owever, kidn ey in juries, ruptured in testin es, an d rectal perforation s can occur. Head in jury is th e m ost frequent cause of death and implies a significant m echanism of injury. Skull fractures involving m ultiple sites with complex configurations are usually nonaccidental. In particular, n onparietal skull fractures are suspicious for abuse. Com m on skeletal in juries from ch ild abuse in clude diaphyseal lon g bon e fractures, in juries to th e m etaphysis/ epiphysis, an d rib fractures. Certain diaphyseal fractures are h igh ly suggestive of n on acciden tal traum a in cludin g spiral fractures of th e h um erus in children younger than 2 years. In addition, fem ur fractures in children before th e walking age are extrem ely concerning for abuse. Metaphyseal “corner’’ fractures seen in the distal fem ur, proxim al tibia, an d distal h um erus an d bucket-h an dle fractures in which the entire periph eral m etaphyseal rim is avulsed are considered characteristic abuse injuries (Fig. 11.291). Rib fractures are very com m on an d can occur from vigorous squeezin g of a child or following a kicking injury. Multiple rib fractures, in various stages of h ealin g, again suggest battery. If child abuse is suspected, hospital adm ission is m an datory. Proper m edical care sh ould be provided, an d ch ild

Figure 11.291 An 11-month-old girl with thigh swelling. Radio-

graph of the distal femur shows corner or “chip” fractures in the metaphysis (bottom arrow). Faint periosteal calcification is also visible along the lateral cortex (top arrow). Such fractures raise suspicion for child abuse. (Reproduced with permission from Beaty JH, Kasser JR. Rockwood and Wilkins’ Fractures in Children. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

protection services sh ould be n otified. Virtually all state an d local jurisdictions now have m andatory laws requiring the reporting of suspected cases of battered child syn drom e; in fact, th e physician m ay be h eld liable for failure to do so.

RECOMMENDED READINGS Flyn n JM, Sarwark JF, Waters PM, et al. Th e operative m an agem en t of pediatric fractures of the upper extrem ity. J Bone Joint Surg Am. 2002;84:2078 –2089. Flyn n JM, Skaggs DL, Spon seller PD, et al. Th e operative treatm en t of pediatric fractures of the lower extrem ity. J Bone Joint Surg Am. 2002;84:2288 –2300. Kay RM, Matthys GA. Pediatric an kle fractures: evaluation an d m an agem ent. J Am Acad Orthop. 2001;9:268 –279. Kocher M, Kasser JR. The orth opaedic aspects of child abuse. J Am Acad Orthop. 2000;8:10 –20. Om id R, Ch oi PD, Skaggs DL. Curren t con cepts review: supracon dylar h um erus fractures in ch ildren . J Bone Joint Surg Am. 2008;90:1121 – 1132.

12

The Spine W illiam Postm a St even Sam W. W iesel

Scherping W illiam Lauerm an

INTRODUCTION All orthopedic surgeons need to be able to effectively evaluate and treat the patients with back or neck pain regardless of th eir subspecialty as sym ptom s surroun din g th e spin e represen t on e of th e m ost com m on reason s for visitin g physician s, an d disease en tities en com passin g th e spin e often m asquerade as problem s in volvin g oth er areas of th e body. Th is ch apter will provide an in troduction to th e m ost com m on problem s in volvin g the adult spine. Th e chapter will begin focusin g on traum a before m ovin g on to degen erative disorders and other associated entities in cluding adult scoliosis. Finally, a brief discussion on spine pathology, including tum or and infection, will en sue. The purpose of this chapter is to provide the reader with a broad, solid basis for un derstan din g an d treatin g spin al con dition s.

SPINE TRAUMA Spinal Cord Injury Spin al cord in jury (SCI) is with out a doubt th e m ost devastatin g con dition en coun tered by th e orth opedic surgeon . No oth er in jury or con dition is as disruptive physically, em otion ally, or econ om ically or h as such a h igh rate of prem ature death an d associated complication s. Described origin ally in th e tim e of Ph araoh s, th ere is a lon g an d pessim istic h istory of th e response of SCI to treatm en t. Labeled by ancient Egyptian physicians as “an ailm ent not to be treated,’’it is only in the latter half of the twentieth cen tury, with th e evolution of special SCI un its, th at an improvem en t in the functional progn osis of SCI patien ts h as been reported. Th e tragedy of SCI is h igh ligh ted by its predilection for young, healthy individuals. Th e incidence of SCI is between 30 an d 50 cases per m illion people per year with little

ch an ge over th e last quarter of a cen tury despite advan ces in car safety, tech n ology, an d laws regulatin g autom otives. Th is estim ates about 11,000 cases of SCI adm itted to em ergency departm ents per year. These num bers do not include the approxim ate 20 cases per m illion people per year involvin g SCI with death at th e scen e of th e acciden t. Th e m ajority (aroun d 60%) of th ese patien ts are between th e ages of 16 an d 30, with m en affected four tim es m ore com m on ly th an wom en . Th e m ost com m on tim e of year for in jury is durin g th e sum m er m on th s, with m otor veh icle acciden ts (MVAs) estim ated to be th e cause approxim ately 50% of the tim e. Followin g MVAs, falls, gunshot woun ds, an d sports-related in juries are all respon sible for aroun d 15% of SCI. In the United States alone, over 200,000 patien ts live with quadriplegia or tetraplegia secon dary to th e effects of SCI. SCIs span a pattern of in jury ranging from complete SCI to isolated n erve root in jury. Complete SCI implies com plete physiologic, alth ough rarely an atom ic, disruption of the spinal cord below the level of injury. With the exception of root sparin g, wh ich m ay be seen on e or two levels distal to th e cord in jury, any fun ction furth er distally is eviden ce of in com plete SCI by defin ition . Th e distin ction is importan t progn ostically as com plete SCI h as a bleak progn osis with fun ction al recovery distal to the lesion being h ighly un likely if n ot im possible. On th e oth er h an d, in com plete SCI carries with it a poten tial for fun ction al recovery to be m ade. Wh en m akin g th e distin ction between complete an d in complete lesion s, it is importan t to en sure th at th e patien t is n ot sufferin g from spin al sh ock because patien ts with spin al shock can appear to have a complete lesion, wh en in actuality, on ce th e shock resolves (generally over 48 –72 hours), the patient can be noted to have an incom plete in jury. Th e bulbocavern osus reflex is used to determ in e wh eth er a patien t is in spin al sh ock an d its recovery m arks th e resolution of spin al sh ock an d th e poin t at wh ich

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progn ostication can be m ade. Th e bulbocavern osus reflex is perform ed by placin g th e exam in er’s fin ger in th e patien t’s rectum an d squeezin g th e glan s pen is or tuggin g on the Foley catheter, resulting in a reflexive contraction of the sph incter. This is a n orm al finding. If th is test is perform ed on an SCI patien t an d is absen t, diagn osis of th e type of in jury (i.e., complete vs. in complete) sh ould be postpon ed un til return of th e reflex, den otin g th e en d of spin al sh ock. Incomplete injuries are furth er divided in to several categories depen din g on th e portion of th e cord affected. In complete syndrom es include anterior cord syndrom e, central cord syn drom e, Brown –Sequard syn drom e, posterior cord syndrom e, and cauda equina syn drom e. An terior cord syn drom e involves in jury to the anterior horn cells, resultin g in disruption of th e corticospin al or m otor tract, m ost com m on ly in th e cervical region . Because of th e level at which these generally occur (i.e., cervical) and because the m otor tract is involved, these patients have the worst progn osis of all in com plete SCI syn drom es. Th ese patien ts m im ic complete in jury secon dary to disruption of th e m otor tract, alth ough th ey gen erally h ave patchy distal sparin g, thus differentiating the two. Poor outcom e is the norm with an terior cord syn drom e. Cen tral cord syn drom e offers a better progn osis th an an terior cord syn drom e an d h as a m uch m ore variable presen tation. The classic description is a hyperextension in jury in an older in dividual with a preexistin g, lon g-stan din g spondylosis. The cord in jury results from either central hem orrh age within the cord or from contusion leading to cen tral edem a durin g th e hyperexten sion in jury. Th e patien ts presen t with sign ifican tly greater im pairm en t of upper extrem ity fun ction th an lower extrem ity fun ction with a variable am ount of sensory disturbance. Bladder an d bowel fun ction are variably affected, th ough usually return to fun ction if affected, an d perian al sen sation is retain ed. Lower extrem ity return of fun ction gen erally precedes upper extrem ity return of function . Clum siness of hands an d a wide-based gait rem ain frequen t long-term sequelae. Brown –Sequard syn drom e describes fun ction al h em isection of th e cord, generally from penetrating traum a, leadin g to ipsilateral paralysis or paresis, with con tralateral loss of pain an d temperature sen se (spin oth alam ic tract), classically two levels below th e lesion. The posterior tract gen erally evades disruption , alth ough with full h em isection , ipsilateral loss of vibration an d proprioception sh ould be observed. Th e syn drom e is rare an d alm ost n ever occurs in its pure sen se. Gen erally, a picture of in complete h em isection of the cord is seen. Posterior cord syndrom e describes sole involvem ent of the posterior colum n , thereby clinically producing loss of sen se of vibration an d proprioception . This is extrem ely rare following traum a. Cauda equin a syn drom e describes in jury to th e n erve roots distal to th e term in ation of th e spin al cord, an d the cord itself is not affected. The spinal cord typically

term in ates at L1-L2, wh ereas th e n erve roots to th e lower extrem ity typically exit th e cord itself two or th ree rows proxim al to this level and traverse the rem ain ing distance un til th ey exit th e can al essen tially as periph eral n erves. Th erefore, injury to this area results in a lower m otor neuron-type lesion with peripheral nerve impin gem en t or dam age. As such, progn osis for recovery is typically better than would be expected for an equivalen t cord in jury, an d m ore aggressive surgical m an agem en t should be employed.

Evaluation Evaluation of th ese patien ts begin s with evaluation an d stabilization of th e en tire m edical con dition followin g th e advanced traum a life support (ATLS) guidelines. The details of ATLS are beyon d th e scope of th is article. Any patien t that has suffered a significant traum a should be assum ed to h ave a spin al in jury un til proven oth erwise. Th erefore, all polytraum a patients at the m inim um sh ould receive lateral radiograph s of th e cervical spin e with visualization of the superior end plate of T1. Wh en possible, a detailed h istory sh ould be obtained eith er from th e patien t or any observers presen t focusin g on th e m ech an ism of in jury as well as any tran sien t loss of n eurologic fun ction at th e tim e of th e in jury. A con vin cing history of transient loss of m otor or sen sory function m ay suggest the occurrence of an incomplete SCI that has resolved rapidly an d m ay affect treatm en t decision m akin g if a fracture is identified. Regardin g th e spin e physical exam in ation , th e en tire spin e m ust be in spected and palpated with the patient logrolled wh ile m ain tain in g in -lin e traction of th e n eck. Ecchym osis, tenderness, or a palpable gap between spinous processes suggests in jury to th e posterior elem en ts, an d supplem en tal radiographic inform ation m ust therefore be obtain ed. Neurologic exam in ation m ust be detailed, system atic, an d docum en ted. It sh ould be repeated at regular intervals. Most SCI centers utilize the Am erican Spinal In jury Association (ASIA) guidelin es for classification an d docum en tation , wh ich is th en en tered in th e patien t’s ch art, facilitatin g accurate iden tification of n eurologic status, progn ostication , an d in m any cases treatm en t. Th e Fran kel gradin g system or a m odification of it is also utilized to classify the extent of function following neurologic injury: ■ ■ ■ ■

■

Frankel A: complete SCI Frankel B: sensory incomplete Frankel C: m otor incomplete, m otor useless Frankel D: m otor incomplete, m otor useful ■ D1: n on am bulatory ■ D2: am bulatory Frankel E: norm al

In addition to docum en tin g in tact or absen t levels of sensation, m otor fun ction m ust be clearly defined and graded on a 0 to 5 scale. By con ven tion , th e spin al level applied to th e injury level (i.e., C6 quadriplegia) refers to th e lowest level with in tact, at least an tigravity, stren gth . It

Chapter 12: The Spine

is also important, when perform ing the neurologic exam ination, to diligently search for eviden ce of sacral sparing, such as retained toe flexion , perianal sensation , and so on . Rectal exam ination and evaluation of the bulbocavernosus reflex are routin ely carried out as described earlier. Radiograph ic assessm en t begin s with a routin e lateral cervical view and proceeds as in dicated per physical exam in ation findings. If the lateral cervical view is negative, an d th e patient is awake and alert without any neck pain subjectively or on physical exam ination, no other views are necessary. If the patient has neck pain, but the lateral view is negative, additional film s include an AP, oblique views, and an open -m outh odontoid view. Of note, 80% of in juries can be iden tified on th e lateral view. Flexion an d exten sion views can be obtain ed in th e n eurologically n orm al patien t under physician supervision, but these have largely been supplan ted by computed tom ography (CT) scannin g th at can be obtain ed quickly in m ost em ergency departm en ts. CT can be used if T1 is n ot visualized on plain film , to look for an in jury n ot presen t on plain film , or to further evaluate a fracture/ dislocation that is apparent on plain film . It offers better defin ition of bony in jury an d can m ore accurately assess canal comprom ise. Magnetic resonance im agin g (MRI) is utilized to assess for in trinsic cord dam age, to evaluate possible cases of posterior ligam en tous in jury, or to assess th e presen ce of a h ern iated disk in a patient with a subluxation or dislocation. The m ajor disadvan tage of MRI is logistic, in cludin g difficulty in troducin g an in tubated patien t or a patien t with ton gs in to th e scanner, as well as th e tim e it takes to scan with an MRI as opposed to th e CT scan . Th e iden tification of any fracture or dislocation of the spine m andates AP an d lateral radiographs of th e en tire spine (or CT scan) due to the high inciden ce of associated noncontiguous injuries, which is as high as 20%. As alluded to earlier, th e iden tification of a fracture in th e cervical, th oracic, or lum bar spin e is typically followed by CT scan n in g of th e area to better defin e bony disruption an d determ in e the presence and extent of spin al canal comprom ise. MRI scannin g is less com m on ly utilized but is m ost helpful for identifying injury to the posterior ligam entous complex to better ascertain stability.

Management As soon as the possibility exists for an SCI injury, the patient should be im m obilized with a backboard. It m ust be em ph asized th at th e backboard or spin e board sh ould be used for tran sportation purposes on ly, an d th e patien t sh ould be safely tran sferred to a bed while protectin g th e spine an d m aintaining im m obilization as soon as th e patient arrives at the hospital. Aside from protecting the spin e from further injury, m anagem ent of the patient with SCI begin s with m edical stabilization . Th is is usually accom plish ed with th e h elp of a gen eral surgery traum a team , an intensive care unit team , an d an orth opedic traum a team followin g th e ATLS algorithm an d protocols as m entioned

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earlier. O f n ote, durin g th is treatm en t, it is im portan t to keep th e patien t’s blood pressure elevated to a n orm al level to adequately perfuse th e spin e an d preven t on goin g in jury from further ischem ia. With regards specifically to the spine, the m ost effective an d importan t early step in treatin g SCI is realign m en t of the spine. In m ost cases, the application of skeletal traction represen ts th e first step in realign m en t, gen erally with th e use of Gardn er–Wells tongs, wh ich are readily available, inexpen sive, an d easy to apply. In itial application of 20 lb of traction with in creasin g weigh t also serves to im m obilize the spine as realignm ent is accomplished. It m ust be em ph asized th at th ere are certain in juries in wh ich traction is contraindicated, which will be addressed under those specific injuries in future sections, but as a general rule, the application of skeletal traction sh ould be carried out on ce a spin al in jury is recogn ized. After th e spin e h as been realign ed, th e presen ce of on goin g compression on th e cord or cauda equin a, as dem on strated by a persisten t neurologic deficit, suggests that decom pression sh ould be con sidered. Most SCI patien ts suffer from n eurologic in jury as a result of either m alalignm en t of th e can al or an terior compression from retropulsed bon e. If a deficit persists after realign m en t, a source of on goin g compression sh ould be sough t an d is usually iden tified on CT scan n in g or MRI. Th e role of decompression in in complete in juries is n ow well accepted with patien ts wh o h ave plateaued n eurologically respon din g well to anterior decom pression an d stabilization . Th is is true even in cases of late decompression . With complete in jury, th e role of decom pression is less clear an d con troversial, alth ough we favor an aggressive approach as som e patients do respond with partial recovery. Th e n ext step is determ in in g stability of th e in jury, wh ich will be discussed later in further detail. If an injury pattern is un stable, surgery sh ould be con sidered to provide stabilization , wh ereas a stable in jury pattern can be treated n on operatively. Because th e m odern approach to SCI m an agem en t in cludes early participation in reh abilitation , an in creasin gly aggressive approach to surgical stabilization is un dertaken in m ost SCI cen ters for patien ts wh o are n eurologically impaired. Even in th e presen ce of complete SCI, surgical stabilization m inim izes or elim inates the need for extern al im m obilization , facilitates early tran sfer to a reh abilitation cen ter, an d m ay m in im ize th e risk of m edical complication s such as pneum onia, skin breakdown , and sepsis. Halo brace im m obilization is com m only utilized in the treatm en t of in juries to th e cervical spin e, eith er with or without n eurologic deficit. It has been dem onstrated repeatedly to provide m arkedly in creased rigidity wh en com pared with oth er extern al orth oses. Th e h alo is routin ely used for im m obilization of upper cervical spin e in juries with som e use in subaxial injuries as well. Complications in clude pin tract in fection s as well as paradoxical m otion or “sn akin g’’of th e lower cervical spin e.

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O n e of th e m ost con troversial topics regardin g spin al cord traum a is the use of high-dose m ethylpredn isolone in the acute setting, although it is routinely used in m ost traum a cen ters. Methylpredn isolon e first sh owed prom ising results in 1990 when Bracken et al. reported on the results of its use in a m ulticen ter, random ized, double-blind study of patients with com plete an d in com plete SCI. Patients with in com plete cord in juries sh owed sign ifican t im provem en t. Th e dose used was an in itial bolus of 30 m g/ kg followed by an infusion rate of 5.4 m g/ kg/ hr. Following Bracken ’s 1990 study (term ed Nation al Acute Spin al Cord In jury Study [NASCIS] 2), it becam e stan dard practice to use th is dose of steroids. In 1997, Bracken was in volved with an oth er study, NASCIS 3, wh ich again was a m ulticen ter, double-blin d, ran dom ized, con trolled trial evaluatin g high-dose m ethylprednisolone. It again sh owed prom ising results th at h ave sin ce becom e scrutin ized. Furth erm ore, the groups who were treated with high-dose steroids had an in creased incidence of wound infection , sepsis, and gastroin testin al (GI) bleedin g. Th ough th ere is n o con sen sus nationwide, the current recom m endations are that patients presen tin g less th an 3 h ours status post a blun t SCI m ay be considered for an initial bolus followed by 23 hours of treatm en t at 5.4 m g/ kg/ hr. Patients presenting between 3 and 8 hours m ay be con sidered for an in itial bolus followed by 48 hours of treatm ent. Those presen ting after 8 hours sh ould not be treated with steroids. Fin ally, on e of th e m ost im portan t aspects of th e in creased success with the treatm ent of SCI is the developm en t of specialty SCI rehabilitation centers for the longterm m an agem en t of th ese in juries. Th is m ovem en t was started and developed at the tim e of an d after World War II by, am on g oth ers, Sir Ludwig Guttm an n . He proposed a list of guidelines, which are still followed today when dealin g with th ese in juries. Guttm an n ’s guidelin es are as follows: ■ ■ ■ ■ ■ ■

Tran sfer to a specialized un it as early as possible Man agem en t supervised by a physician kn owledgeable in SCI care A team of allied h ealth profession als train ed in SCI m an agem ent and complications Com m itm en t to vocation al reh abilitation Com m itm en t to addressin g psych osocial an d recreation al needs Provision for lifetim e follow-up care of th e SCI patien t

An ongoing federally sponsored system of SCI rehabilitation cen ters based on Guttm an n ’s guidelin es was begun in the United States in 1970 and has without a doubt greatly improved patients’functional an d em otional outcom es.

SPINAL STABILITY When decidin g upon treatm en t for particular injuries to the vertebral colum n , on e n eeds to un derstan d th e stability of

th e spin e an d essen tially wh at m akes an in jury stable or un stable. Wh ite an d Pan jabi defin ed spin al stability as th e ability of the spin al m otion segm ent to resist forces, either acutely or chronically, so as to prevent the developm en t of n eurologic in jury, pain , or spin al deform ity. Th e differen t region s of th e spin e h ave differen ces in an atomy an d various forces applied, th us con tributin g to differen ces in th e stability. Th is m ust be con sidered when determ ining which injury patterns are stable and which are unstable. For example, th e cervical spine is m ore inherently unstable than th e th oracic spin e sin ce th e th oracic spin e h as th e added stability of th e ribs and less m otion is allowed through th e th oracic spin e. Th erefore, alth ough a good defin ition of stability h as been provided, the question rem ains h ow to determ in e wh eth er an in jury is stable as th is will ultim ately guide m an agem ent. Although one would thin k that such an important concept would h ave firm guidelin es, th ere h ave been m any proposition s of criteria for th e establish m en t of stability, but all h ave flaws an d n on e are un iversally accepted. Wh ite and Panjabi attempted to provide firm guidelin es defining th e con cept of “clin ical stability’’of th e spin e, wh ich h igh lights th e important concepts on e needs to consider. They devised a ch ecklist assign in g poin ts to various aspects of th e in jury in cludin g radiograph ic criteria, n eurologic status, and anticipated physiologic loads. Critics of this system n ote difficulty in applyin g it to clin ical situation s and lack of validation . Alth ough n ot perfect, it is a very useful tool wh en determ in in g spin al stability. Con ceptually importan t an d easier to apply is th e proposition of Den is with h is “three-colum n theory’’for the stability of th e th oracolum bar spin e (Fig. 12.1). He divides th e th oracolum bar spin e in to th ree colum n s an d suggests th at instability occurs when two of the three colum ns are disrupted. Alth ough th is th eory con siders only radiographic criteria, it is easy to un derstan d an d also establish es an im portan t con cept for evaluatin g spin al im ages. Th e an terior colum n con sists of th e an terior lon gitudin al ligam en t an d th e an terior h alf of th e vertebral body. Th e m iddle colum n con sists of th e posterior h alf of th e vertebral body an d posterior lon gitudin al ligam en t (PLL). Th e posterior colum n com prises th e rem ain in g bony an d ligam en tous structures, specifically the posterior bony arch (pedicles, lam ina, spin ous processes), the facet joints, the ligam entum flavum , the in terspin ous ligam en t, an d th e supraspinous ligam ents. A sim ilar system was proposed in JBJS 2007 by An derson et al. for th e cervical spin e. Th ey broke th e cervical spin e in to four colum n s an d assign ed n um eric values to th e degree of disruption of each colum n . Th eir proposed system is term ed th e cervical spine injury severity score (CSISS). Although there have been num erous system s proposed for defining stability without any being completely accepted, it is im portan t to un derstan d wh at factors con tribute to th e stability. Th ese include the in jury pattern, n eurologic status, patien t’s overall h ealth status, associated


A

439

B

Figure 12.1 Denis 3 column. Illustration depicting

C

injuries, and potential for healing of the injury. Specific injuries will be discussed in future section s and the stability of each lesion will be discussed as well to better grasp this difficult concept.

CERVICAL SPINE ANATOMY Th e cervical spin e con sists of th e region between th e cervicocran ium jun ction an d th e C7 –T1 articulation . Th e cervical spine can essentially be divided into two separate areas: the upper cervical spin e an d th e subaxial spin e. Th e upper cervical spine con sists of the region between the base of skull an d C2, the axis. This area is unique from th e rem ain der of th e cervical spin e in th at each articulation h as its in dividualized an atomy, whereas the subaxial spine has little variation between articular segm ents. As previously m entioned, the upper cervical spine consists of three importan t structures and their articulation s: the base of th e skull, the atlas (C1), an d the axis (C2). The base of th e skull articulates with th e atlas th rough two large con dyles projectin g from the base of the skull an d conform ing with the two lateral m asses of the atlas, essentially holding up the skull. Th e anterior and posterior arch es of the atlas connect the lateral m asses form ing a large cen tral hole, allowing the passage of the spinal cord in this

Denis’s three-column model. (Reproduced with permission from Chapman MW. Chapman’s Orthopaedic Surgery, 2nd ed. Philadelphia, Lippincott Williams & Wilkins, 1993.)

region . Th e articulatin g surfaces are furth er stabilized by ligam en tous an d capsular attach m en ts. C1 subsequently articulates with C2, the axis, th rough three separate articulations. The first is through the superior projection of C2, the den s, articulatin g with the posterior aspect of th e an terior arch , an d th e oth er two are through the paired facets of th e atlas and axis. The axis addition ally h as a bifid spin ous process th at can be h elpful wh en trying to iden tify it. Th e unique C1 –C2 an atomy allows a sign ifican t am oun t of con trolled rotation to occur through the atlantoaxial articulation , wh ereas the occipitalC1 articulation provides a substan tial degree of flexion an d exten sion . Th e upper cervical spin e is furth er stabilized by ligam en tous attach m en ts both extrin sic to th e can al an d with in th e spin al can al itself. The attachm en ts external to the canal in clude th e ligam en tum flavum , an terior lon gitudin al ligam en t, in tervertebral disks, an d th e join t capsules. Th e stronger ligam en tous attachm ents within the can al include the tectorial m em brane, th e cruciate ligam en ts (includin g the transverse atlan tal ligam ent), an d the odontoid ligam en ts, specifically th e alar an d apical ligam en ts (Fig. 12.2). Th ese ligam en ts provide th e m ajority of stability to th e upper cervical spin e. Th e subaxial cervical spin e con sists of th e vertebral segm en ts of C3 –C7, wh ich all h ave very sim ilar an atomy. Th e

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Figure 12.2 Upper cervical spine ligamentous anatomy. Illustration depicting the ligamentous

anatomy in the occipitocervical region from posterior, anterior, sagittal, and superior views. (Reproduced with permission from Frymoyer JW, Wiesel SW, An HS, et al. The Adult and Pediatric Spine, 3rd ed. Philadelphia: Lippincott Williams & Wilkins, 2003.)

vertebral bodies h ave a sligh tly oval sh ape with th e coronal distance larger than the sagittal distance. Th e pedicles project from th e body in a posterolateral direction with th e facets subsequen tly arisin g from th e posterior portion s of the pedicles. Th e superior facets of th e inferior segm ent articulate with th e in ferior facets of th e superior vertebral segm en t, comprising the diarthrodial facet joints. The superior facets face posteriorly an d lie an terior to th e in ferior facets, wh ereas th e in ferior facets face an teriorly an d lie posterior to th e superior facets. In th e cervical spin e, th ere is a 45-degree in clin ation of th e facet join t, wh ile th ere is no facet an gulation in the coronal plane (the facets face directly an terior/ posterior). The area of bone between the superior and inferior facets in a sin gle segm en t is referred to as th e lateral m ass, an d th e lam in a subsequen tly arise from th ese structures. Th e lam inae are oriented posterom edially and com bin e to close th e posterior rin g of th e spin al can al an d con tin ue posteriorly form ing the spinous processes. Typically, th e spinous processes of C2 –C6 are bifid, differen tiatin g th em selves from C7 an d th e rem ain in g spin ous processes th at h ave a sin gle projection . The transverse processes of the subaxial cervical spine are un ique in th at th ey h ave a foram en th at allows passage of th e vertebral artery. Th e vertebral artery typically en ters

into th e transverse processes above C7 and thus the foram ens of C6 –C1 tran sm it passage th rough th e n eck. Classically, th e C7 foram en does n ot h ouse th e vertebral artery but on e of th e vertebral vein s. Th ere are several soft-tissue structures in th e subaxial cervical spin e, wh ich h elp m ain tain stability an d dissipate forces. The importan t elem ents anteriorly are the an terior longitudinal ligam ent, th e PLL, and the intervertebral disk th at lies between th e an terior an d PLLs. Th e lon gitudin al ligam ents lie an terior and posterior to the vertebral bodies th e en tire len gth of th e spin al colum n . Posterior stability is m aintained by the ligam entum flavum , facet joint capsule, interspinous ligam en ts, and supraspin ous ligam ents, also known as the ligam entum nuchae in the cervical region. Th ese structures provide stability m ain ly with flexion . Fin ally, it is im portan t to un derstan d th e cervical n erve roots an d h ow th ey are n um bered in relation to th e vertebral level as th is is th e basis for un derstan din g an d locatin g cervical root path ology. Th e roots are n um bered for th e vertebral level below th em in th e cervical spin e as th ey exit. Th erefore, th e C5 n erve root exits between C4 an d C5. Un like th e lum bar spin e, in the cervical spine, a hern iated disk or disk path ology im pin ges on th e exitin g n erve root th e vast m ajority of th e tim e. Th erefore, a h ern iated disk between C4 an d C5 im pin ges on th e C5 n erve root, th e


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exitin g root, resultin g in a C5 radiculopathy. Followin g th e sam e pattern , a C5 –C6 disk affects th e C6 root; th e C6 –C7 disk affects th e C7 root; an d th e C7 –T1 disk affects th e C8 root. It sh ould be recogn ized th at as th ere is n o C8 vertebral body, th e n um berin g of th e n erves ch an ges to th e vertebral level above th e exiting root in the thoracic spine. Of note, the m ost com m on areas of disk herniation in th e cervical spin e are C5 –C6 affecting th e C6 n erve root an d C6 –C7 affectin g C7.

Radiographs of the Cervical Spine Th e tim in g an d in dication s for orderin g differen t radiograph s is very im portan t to un derstan d an d is covered in differen t section s in th is article. Equally im portan t is th e ability to read radiographs, CT, and MRI scans. An in -depth discussion on th is subject is beyon d th e scope of th is article, but this section will discuss the basics of reading plain radiograph s an d CTscan s with emph asis on th e traum a setting. Radiographic assessm ent of the cervical spine starts with an im age of th e lateral cervical spin e an d proceeds as indicated. Typically, a lateral, AP, and open-m outh odontoid views will be obtain ed of th e cervical spin e, followed by a CT scan if an abnorm ality is found or suspected. For the lateral view to be adequate, it m ust allow visualization of th e superior en d plate of T1. If adequate visualization is lacking, a swim m er’s view can be obtained, but m ost will obtain a CT scan to en sure visualization . Many in stitution s will get a CT scan with th e in itial workup or in lieu of plain radiograph s secon dary to th e speed an d ease with wh ich CT scans can now be done. CT scans provide very good detail of th e bony an atom y an d relation sh ips an d excellen t visualization of the occipital cervical region and cervicothoracic jun ction th at can be difficult to evaluate with plain film s. Additionally, sagittal and coronal reconstructions, wh ich are routinely done with CT scanning, allow a clearer picture of the injury. It m ust be noted, however, that axial CT im ages alone can m iss in juries that are in the plan e of th e cut. When readin g radiograph s of th e cervical spine, it is very important to have a system atic approach , especially when first begin n in g, to decrease th e likelih ood of m issin g an in jury. Th e lateral radiograph or sagittal CT scan is n ot on ly the easiest to evaluate but also provides the m ost in form ation. Approxim ately 80% of in juries can be picked up on the lateral radiograph . Alignm ent sh ould first be evaluated by followin g th e sm ooth progression of four lon gitudinal lines along the anterior vertebral body, posterior vertebral body, lam in a (spin al lam in ar lin e), an d spin ous processes. A sm ooth curvilinear relationship should exist. If there is a disruption in any of th ese lin es, an in jury likely exists an d the radiograph should be scrutinized carefully for fracture or dislocation . Prevertebral swellin g sh ould also be n oted on th e lateral radiograph s as in creased swellin g often in dicates an un derlying occult fracture. Prevertebral swellin g is evaluated by observin g th e prevertebral soft tissue sh adow.

Figure 12.3 Lateral cervical spine radiographic lines. X-ray lines,

landmarks, and measurements using a lateral cervical spine film. The spinolaminar line (A), posterior vertebral line (B), and anterior vertebral line (C) are normally unbroken. On a perfect lateral view the facet joints should appear as stacked parallelograms (D). The prevertebral soft tissue shadow is measured at the C2–C3 (E) and C6–C7 (F) disk spaces. More than 6 to 7 mm at C2–C3 or 21 mm at C6–C7 is strongly suggestive of underlying spinal injury. (Reproduced with permission from Bucholz RW, Heckman JD, Court-Brown C, et al. Rockwood and Green’s Fractures in Adults, 6th ed. Philadelphia, Lippincott Williams & Wilkins, 2005.)

If th is sh adow is greater th an 7 m m at th e C2 –C3 junction or m ore th an 21 m m at th e C6 –C7 junction, a high likelih ood for an underlying injury exists and further workup sh ould be don e (Fig. 12.3). Aside from the relation ships discussed previously, th ere are several specific relation ships and m easurem ents in the upper cervical spin e th at sh ould be evaluated as well. Several m easurem en ts an d relation sh ips h ave been described, and there are different proponents for all. The following will be discussed briefly: Wacken h eim ’s lin e, atlan toden s interval (ADI), space available for the cord (SAC), anterior spin al lam inar lin e, an d Powers ratio. Wackenheim ’s line describes an im agin ary lin e represen tin g th e exten sion of th e clivus distally. In th e n orm al spin e, th e tip of th e odon toid should fall within 2 m m of th is im agin ary line. On e sh ould be suspicious for possible occipitocervical injury sh ould this relation sh ip be skewed. Th e ADI is the distan ce from th e posterior portion of the anterior arch of C1 to th e anterior portion of the dens as it articulates with C1. This

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Orthopaedic Surgery: Principles of Diagnosis and Treatment Dens angulation

Wackenheim's line

C1-C3 Spinolaminar line 6 mm

A

B

LADI within + 2 mm Joint "spaces" 1-2 mm 2-3 mm

PAL-B: < 4 mm < 12 mm DBI < 12 mm

No overhang < 15% Normals

D C

ADI < 3 mm (5 mm)

Figure 12.4 Upper cervical spine lines. (A) Prevertebral shadow at C2–C3 should not exceed

6 mm in a healthy patient without an endotracheal tube in place. (B) Bony screening lines and dens angulation. The anterior cortex of the odontoid should parallel the posterior cortex of the anterior ring of the atlas. Any deviation should be viewed with suspicion for an odontoid fracture or injury the TAL. Wackenheim’s line is drawn as a continuation of the clivus caudally. The tip of the odontoid should fall within 1 to 2 mm of this line. The C1–C3 spinolaminar lines should fall within 2 mm of one another. (C) Ligamentous injury reference lines. The ADI should be less than 3 mm in adults. The SAC is measured as the distance from the posterior cortex of the odontoid tip to the anterior cortex of the posterior arch of the atlas and should measure greater than 13 mm typically. The dens-basion interval (DBI) is the distance between the odontoid tip and the basion. It should be less than 12 mm in the adult. The posterior axis line (PAL-B) should not be more than 4 mm anterior and less than 12 mm posterior to the basion. (D) Bony screening lines. The left and right lateral atlantodens interval (LADIs) should be symmetric to one another (within 2 mm of deviation). The bony components of the atlanto-occipital joints should be symmetric and should not be spaced more than 2 mm apart on AP images. The combined lateral overhang of the lateral masses should also not exceed 7 mm. (Reproduced with permission from Bucholz RW, Heckman JD, Court-Brown C, et al. Rockwood and Green’s Fractures in Adults, 6th ed. Philadelphia, Lippincott Williams & Wilkins, 2005.)

distan ce sh ould be less th an 3 m m . Fractures of th e odon toid an d C1 –C2 dislocation / subluxation can cause th is distan ce to be greater. Th e SAC represen ts th e region from th e posterior aspect of th e den s or th e posterior aspect of th e vertebral bodies to th e an terior aspect of th e posterior arch . In th e cervical spin e, th is distan ce will typically be greater than 13 m m in the average adult. The an terior spinal lam inar line is an im aginary line from th e opisth ion alon g th e an terior aspect of th e posterior arch of C1 an d th e lam inae of C2, C3, an d the rem aining subaxial cervical spine as m en tion ed earlier. Th is lin e sh ould rem ain sm ooth an d curvilinear. Any deviation from the norm of the relationsh ips described earlier sh ould alert th e physician to probable fracture or dislocation an d furth er evaluation sh ould be don e. Fin ally, th e Powers ratio is th e ratio of th e distan ce

between th e basion (or clivus) an d th e posterior arch of C1 to the distance between the opisthion and the anterior arch of C1. Norm ally, this ratio should be less than 1. A ratio greater th an 1 suggests th e likelih ood of an occipitocervical dislocation. Th ese relationships are n ot inclusive of th e described radiograph ic m easurem en ts of th e cervical spin e but rath er provide the m ost com m on m easurem ents utilized or discussed (Figs. 12.4 an d 12.5). Th e AP radiograph an d th e open -m outh odon toid views provide less in form ation th an th e lateral radiograph , but th ere are several im portan t relation sh ips th at n eed to be evaluated. On th e AP view, th e pedicles sh ould be evaluated and the interpedicular distance sh ould be sym m etric th rough out th e cervical spin e. Widen in g of th e in terpedicular distan ce suggests a fracture, typically a burst fracture.


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Figure 12.5 Powers Ratio If BC:DA > 1, then

an antero-occipitoatlantal dislocation exists. Ratios less than 1 are normal except in posterior dislocations, associated fractures of the odontoid process or ring of the atlas, and congenital anomalies of the foramen magnum. (Reproduced with permission from John W Frymoyer, Sam W. Wiesel, et al. The Adult and Pediatric Spine. Philadelphia: Lippincott Williams & Wilkins, 2004.)

On the open-m outh odontoid, the odontoid should be well visualized as well as the lateral m asses of C1. The odon toid sh ould be sym m etric between th e lateral m asses of C1. The lateral m asses of C1 should also articulate sym m etrically inferiorly with C2. Any asym m etry should alert the physician to probable ligam entous injury or fracture of the ring of C1. If there is asym m etry or widenin g of the lateral m asses, on e should evaluate the com bin ed lateral spread or overhan g of the lateral m asses of C1 (Fig. 12.4). Th e com bin ed exten sion laterally of th e lateral m asses of C1 over C2 should be less than 7 m m . Greater than 7 m m of com bin ed spread is associated with tran sverse atlan tal ligam ent (TAL) disruption. Whenever an in jury is suspected or identified, a CT scan is usually obtained. As m entioned earlier, the CT scan sh ows detailed bony anatomy, an d sagittal an d coron al recon structions allow evaluation in three planes. Th e sam e relation sh ips discussed earlier with plain film s can be used to evaluate CT scan s with th eir respective coun terparts (i.e., AP to coronal recons and lateral to sagittal recons). Additionally, fractures throughout the cervical spine are m uch easier to appreciate on CT scan , especially to th e un train ed eye. Th e discussion of MRI is beyon d th e scope of th is article, but it should be appreciated that MRI evaluates the soft tissues better than CT but does not provide as clear a picture of the bony anatomy. Therefore, herniated disks, cord/ n erve root im pin gem en t, an d ligam en tous in juries, am on gst oth er path ology, are best evaluated with this m odality, while CT scan better visualizes bony structure.

UPPER CERVICAL SPINE TRAUMA Craniocervical Dissociation Cran iocervical dissociation is a rare, com m only fatal con dition in wh ich th e ligam en tous structures con n ectin g th e occiput to th e atlas becom e disrupted with subluxation or dislocation of th e occiput. Th e m ost com m on m ech an ism

of in jury results from m otor veh icle acciden ts. For patien ts wh o do survive, th ey m ay have subtle or no neurologic deficits because a dissociation resultin g in n eurologic com prom ise essen tially results in death . Th ese patien ts h ave a h ighly un stable in jury despite th eir preserved n eurologic function, and thus a h igh degree of suspicion and prompt recogn ition of th e in jury is essen tial as n eurologic fun ction can decline rapidly if th ese patients are not im m obilized. It m ust be noted that ch ildren , particularly th ose under the age of 8, are predisposed to these injuries secondary to th eir relative ligam en tous laxity an d larger h ead size. As these injuries are purely ligam entous in nature, th ere will be n o fracture seen on plain film s, so on e n eeds to look for m ore subtle radiograph ic fin din gs, in cludin g prevertebral soft-tissue swelling (should not exceed 6 m m in adults), in creased Powers ratio, an d abn orm ality of Wacken h eim ’s lin e. Followin g recogn ition of th is in jury or if th e in jury is suspected, im m ediate im m obilization in a halo vest should be con sidered prior to furth er im agin g studies. Once the diagnosis is establish ed prompt, aggressive treatm en t is in dicated. Typically a cran iocervical fusion will be perform ed after in itial h alo-vest im m obilization . Non operative treatm en t will alm ost always result in persisten t in stability as th e in jury is usually a purely soft-tissue in jury.

C1 Ring Injury-Fractures of the Atlas Fractures of C1 are relatively com m on in juries, accounting for approxim ately 10% of all cervical spine injuries. Th e fractures th em selves gen erally occur with out n eurologic sequelae because C1 is in th e sh ape of a ring, and a fracture gen erally results in expan sion of th e ring with m ore room available for the cord. These fractures also have a high rate of associated injuries, so close exam ination of th e rem ain in g vertebral colum n is essen tial, especially radiograph ically. Com m on associated in juries, as m igh t be expected secon dary to th eir in tim ate relation sh ip to C1, in clude odon toid fractures, Han gm an ’s fractures (C2), an d TAL disruption .

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A

B

Figure 12.6 Jefferson Fracture (A) The open-mouth odontoid view shows bilateral overhang

of the C1 lateral masses relative to the C2 facets, with combined lateral displacement measuring 13 mm. (B) Axial CT image shows a true Jefferson fracture in the form of a four-part burst fracture of the atlas. This fracture is unstable secondary to the associated TAL disruption. (Reproduced with permission from Bucholz RW, Heckman JD, Court-Brown C, et al. Rockwood and Green’s Fractures in Adults, 6th ed. Philadelphia, Lippincott Williams & Wilkins, 2005.)

Fractures of th e rin g of C1 m ay occur an teriorly, posteriorly, an d/ or laterally an d m ay con sist of on e to four fracture lin es. Th e classic m ech an ism of in jury is a direct h it to the top of th e h ead producin g a pure axial load compressing C1, resulting in the well-known eponym , the “Jefferson fracture,’’wh ich classically describes a burst fracture resulting in disruption of both th e anterior and posterior arches producin g four differen t fractures. Th ere are several oth er fracture patterns dependin g on the degree and direction of flexion / exten sion of th e n eck an d resultan t vector of th e force producing the fracture. For example, a hyperextended neck with a concom itant posterior load can cause a posterior arch fracture alon e or vice versa for a hyperflexed n eck resultin g in an isolated an terior arch fracture. Th e degree of force applied dictates wh eth er th e TAL will be disrupted, wh ich is th e key to th e stability of th e fracture. When evaluatin g th ese fractures radiographically, routin e radiograph s of th e cervical spin e often reveal n o evidence of fractures even in th e case of m ultiple fractures. It is therefore essential to obtain an open-m outh odontoid view to look for spread of th e lateral m asses of C1, wh ich is evidence for C1 rin g disruption . Spen ce et al. foun d th at com bined extrusion of both lateral m asses of 7 m m or m ore to be con sisten t with TAL disruption . Furth er evaluation of th ese in juries sh ould be don e usin g a CT scan with fin e cuts to visualize the full extent of the injury an d help with decision m akin g regardin g th e treatm en t (Fig. 12.6). Non operative treatm en t is in dicated for th e vast m ajority of th ese fractures an d patien ts gen erally do well, as dem on strated by th e series of patients of Levine an d Edwards. Min im ally displaced fractures can be treated in either a cervical orth osis or a h alo vest, depen din g on th e in jury, for a period of aroun d 3 m on th s. Displaced fractures require reduction with traction or prolon ged traction followed by h alo vest. Cases treated n onoperatively need to be followed up reg-

ularly with radiograph s to en sure th at reduction h as been m ain tain ed. Surgical treatm en t is occasion ally n eeded for severely displaced fractures, which consists of C1 –C2 fusion or occasion ally C2-occiput fusion . Associated injuries complicate m atters, an d m an agem ent m ust be individualized in th ese situation s.

Odontoid Fractures Odontoid fractures accoun t for 15% to 20% of all cervical spin e fractures an d are th e m ost com m on fracture of the axis. These fractures are particularly com m on in the very young and th e elderly, ages in which failure to recognize the injury, always a com m on problem , is even m ore likely. Th e m ost com m on m ech an ism of in jury depen ds on th e population in volved with falls accoun tin g for th e m ajority of th e cases in th e elderly an d pediatric population , an d MVAs accounting for the vast m ajority in young adults and m iddle-aged population . Th e bony, ligam en tous, an d vascular an atomy surroun ding th e odontoid (dens) is unique an d pertin ent for understan din g th e m ech an ism of in jury, m an agem en t, an d complications of these fractures. The odontoid consists of a broad base with a tooth like projection exten ding from the body of th e axis th at articulates with th e posterior portion of th e an terior arch of th e atlas providin g in h eren t bony stability through th is configuration. The intricate ligam entous complex en compassin g th e odon toid greatly en h an ces stability. Th e TAL of th e cruciate complex (Fig. 12.2) form s a slin g aroun d th e posterior portion of th e den s an d serves as the prim ary restraint to anterior translation of C1 on C2 and the prim ary stabilizer of atlantoaxial m otion. Secon dary stabilizers in clude th e apical an d alar ligam en ts origin atin g from th e base of th e skull an d in sertin g on th e tip of the dens. Because of these in sertions on th e dens,


Type I

A

Type II

B

Type III

C Figure 12.7 Anderson and D’Alonzo odontoid fracture clas-

sification. (A) Type I fracture-alar ligament avulsions. (B) Type II fracture-odontoid waist fractures. (C) Type III fracture extends into the body of C2. (Reproduced with permission from Bucholz RW, Heckman JD, Court-Brown C, et al. Rockwood and Green’s Fractures in Adults, 6th ed. Philadelphia, Lippincott Williams & Wilkins, 2005.)

soft-tissue ten sion m ay create a traction force to distract th e fracture through th e waist and contributes to nonunion. As on e m oves down to the base of the dense, there is relative th in n in g of th e bon e before reach in g th e cortical m argins of th e vertebral body of C2, rendering this region susceptible to fracture, accounting for the m ajority of odon toid fractures (Type II fractures). On ce th ough t to be due to its lack of blood supply in th is region , th e h igh rate of nonunion in this region is m ost likely due m ore to distraction than ischem ia. Studies have now dem on strated a rich an astom osis from contributions by the vertebral an d carotid arteries. Alth ough this blood supply m ay be temporarily disrupted, it is n ot th ough t to con tribute to nonunion assum ing adequate reduction. The m ost widely used classification for odon toid fractures was devised in 1974 by An derson an d D’Alon zo, wh ich divides th e fractures in to three types (Fig. 12.7). The classification stood the test of tim e as it is easy to use, guides treatm ent, and inform s of prognosis, which are th e m arks of a good classification system . Type I fractures occur th rough th e tip of th e odon toid, superior to th e in sertion of th e TAL, an d com m on ly represent an avulsion of th e alar ligam ent. These are the least com m on odontoid fracture an d are quite stable in isolation; however, one needs to rule out craniocervical

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dissociation as th is can be associated with th is type of fracture. Type II fractures, as previously pointed out, occur through the base of the odontoid and are the m ost com m on fracture pattern. The reported rate of nonunion h as ran ged from 15% to 85% with n on operative treatm ent an d aroun d 10% with operative treatm en t. In actuality, for all cases, th e rate is aroun d 30% to 40%. Risk factors for n on union include in itial displacem en t of 5 m m or greater (m ost importan t), patien t age, posterior displacem en t, an gulation at th e fracture site, an d delay in diagn osis. If on e h as persistent distraction at th e fracture site, th e fracture will alm ost assuredly result in n on un ion . Fin ally, Type III fractures exten d in to th e body of C2, th ereby providin g a greater surface area an d greater involvem ent of can cellous bone, both of wh ich prom ote fracture h ealin g, m akin g n on un ion m uch less likely th an with Type II in juries. Alth ough low-en ergy m ech an ism s accoun t for fractures in th e elderly, m ost odon toid fractures occur as a result of h igh -en ergy in jury, an d as such , associated in juries are com m on. Th erefore, as with other spinal traum a, a thorough evaluation is m an datory. Patien ts gen erally com plain of n eck pain an d pain aroun d th e base of th e skull. Neurologic deficit is un com m on occurrin g in less th an 10% of the cases because there is gen erally a large am oun t of SAC in th is region . However, as on e m igh t expect, th ose patien ts with posterior subluxation are at increased risk. On physical exam ination, one can typically elicit pain with palpation at th e base of th e skull, an d m uscle spasm is com m on . Radiograph ic exam in ation begin s with th e stan dard cervical spin e traum a radiograph s. Close exam in ation of th ese radiographs is warranted as th ese fractures can be easily m issed, especially in th e elderly with preexisten t degen erative ch an ges obscurin g th e fracture. Failure to recogn ize the fracture is not un com m on and m ost assuredly will result in non union if n ot m ore catastrophic instability. The two m ost im portan t im ages for iden tification of an odon toid fracture are th e lateral an d th e open -m outh odon toid views. If th ere is any question at all, or if a fracture is iden tified, a CT scan of th e cervical spin e sh ould be obtain ed with th in cuts. It m ust be n oted, however, that it is possible to m iss a fracture on th e CT scan if th e CT im age is obtain ed in th e plan e of th e fracture, even with coron al an d sagittal recon struction s. MRI can be used if an occult odon toid fracture is suspected or to evaluate associated ligam entous in juries. Th e treatm en t depen ds on th e type of fracture as alluded to earlier. Isolated Type I fractures are best treated symptom atically with bracin g for com fort with rare complication s. However, if th ere is associated cran iocervical dissociation , it sh ould be treated accordin gly. Treatm en t of Type II fractures is m ore con troversial secon dary to th e high incidence of n onunion. Those patien ts with n ondisplaced or m in im ally displaced fractures reduced adequately via closed m ean s can be successfully treated nonoperatively with h alo-vest im m obilization for a period of 12 weeks. Th is treatm ent would include fractures with less th an 4 m m

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A

B Figure 12.8 Odontiod fracture treated with anterior screw fixations. (A) Saggital CT scan image demonstrating a Type II odontiod fracture sustained in a fall. (B) Post-operative films demonstrating fixation with a single anterior screw.

of displacem en t, an gulation less th an 10 degrees, youn ger patien ts with good bon e quality, an atom ic reduction , an d early recogn ition of th e fracture (with in 7 –10 days). Collar im m obilization is in adequate as it does n ot con trol atlan toaxial m otion an d will result in n on un ion . After 12 weeks, th e h alo is rem oved an d th e patien t is reim aged. If th e fracture h as h ealed adequately, n o addition al treatm en t is n ecessary. If th ere is eviden ce of n on un ion , dyn am ic (flexion / exten sion ) views sh ould be obtain ed to look for displacem en t at th e n on un ion site. If n egative, the patient can be followed with radiographs at 1 m on th , 3 m on th s, an d 1 year to verify a stable n on un ion . If m otion does occur, surgical in terven tion m ay be required. Surgical in terven tion is n ecessary for m any Type II odon toid fractures. Relative in dication s in clude displaced fractures (> 4 m m ), angulation greater than 10 degrees, delayed presen tation (typically > 10 –14 days), associated in juries, elderly patien ts wh o can n ot tolerate a h alo, an d oth er risk factors for n on un ion . Tradition al surgical treatm en t in volves a posterior C1 –C2 fusion . An oth er popular m eth od is prim ary fixation with placem en t of an an terior odontoid screw(s) (Fig. 12.8). Proper patient selection is n ecessary for successful treatm en t in cludin g n on com m in uted fracture, tran sverse fracture or fracture lin e an gled from anterior-superior to posterior-inferior to allow screw placem en t perpen dicular to th e fracture, good bon e quality, reducible fracture, an d a n on -obese patien t (large body habitus prevents proper drill orientation when attemptin g to obtain th e proper an gle for screw in sertion ). Typically

on e or two 3.5-m m screws are placed. It m ust be n oted th at th is is a tech n ically dem an din g procedure an d sh ould n ot be perform ed by surgeon s with out th e proper experien ce. Fin ally, Type III fractures, secon dary to th eir abun dan t blood supply an d relative fracture stability, rarely go on to n onun ion and th erefore rarely require surgical stabilization. However, th ese fractures should be treated with halo im m obilization as nonunion can occur with cervical orth osis on ly. Operative stabilization , th ough un com m on ly n eeded for th ese fractures, does play a sm all role. Th e m ainstay of operative treatm en t is posterior C1 –C2 fusion as prim ary screw fixation h as resulted in h igh failure rates. Relative indication s are sim ilar to those for Type II fractures; h owever, displacem en t is less com m on ly seen in comparison with Type II fractures.

Traumatic Spondylolisthesis of the Axis (Hangman’s Fracture) Traum atic spondylolisthesis of the axis accounts for approxim ately 15% of all cervical spin e fractures an d is th e secon d m ost com m on fracture of C2 accountin g for approxim ately 35%. Th ere is a sign ifican t fascin ation with th is injury am ong physicians from all specialties secondary to its unique historical significance. When judicious hanging was refined sufficiently so that instant death was achieved with out avulsin g th e subject’s skull, th e subm en tal kn ot used resulted in a bipedicular fracture of C2, wh ich is n ow im m ortalized as the Han gm an ’s fracture. The pars


interarticularis of the axis represen ts a zone of transition from the anteriorly placed facet joints of th e occiput to C2 to th e posteriorly placed facet join ts of th e subaxial cervical and th oracolum bar spine. Th e relatively thin pars at this site is therefore susceptible to injury, particularly from a hyperexten sion force. Subsequent flexion is believed to disrupt th e PLL an d th e disk, resultin g in an terior displacem en t in m ore un stable injuries. The typical m echanism seen today occurs as result of MVAs with hyperexten sion an d an axial load (rath er than the historical hyperextension/ distraction), resultin g in a fracture of the pars. Th e subsequent rebound flexion described earlier with PLLan d C2 –C3 disk disruption occurs by the sam e m echan ism . It m ust be noted th at Hangm an’s fractures have a high m ortality rate at th e scen e of th e acciden t, anywh ere from 25% to 70%, alth ough on ce th e treatm en t is in itiated, th e m ortality rate falls to about 2%. O n th ose survivin g th e in itial accident, n eurologic injury occurs in only 5% to 10% of patien ts. Th e classification of Han gm an ’s fractures was first proposed by Effen ti an d h as subsequen tly been m odified by Levine and Edwards and then by Starr and Eism on t who added Type IA (Fig. 12.9). Th e classification is based upon

A

B

C

D

Figure 12.9 Levine and Edwards classification of traumatic

spondylolisthesis of the axis (Hangman’s fracture). (A) Type Inondisplaced fracture of the pars interarticularis. (B) Type IIdisplaced fracture of the pars interarticularis. (C) Type IIa-displaced fracture of the pars with disruption of the C2–C3 discoligamentous complex. (D) Type III-dislocation of the C2–C3 facets with fracture of the C2 pars interarticularis. (Reproduced with permission from Bucholz RW, Heckman JD, Court-Brown C, et al. Rockwood and Green’s Fractures in Adults, 6th ed. Philadelphia, Lippincott Williams & Wilkins, 2005.)

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th e an gulation an d tran slation resultin g from th e fracture, wh ich in directly dem on strates th e degree of ligam en tous injury associated with the fracture. Type I fractures occur from a hyperextension in jury with axial load, as previously discussed, with n o secon dary flexion in jury. Th is results in a fracture through the pars (m ajority bilateral) with m inim al translation (< 2 –3 m m ) an d no angulation. These fractures are stable as the PLL and the C2 –C3 disk rem ain in tact. Th e Type IA subclassification results from a sim ilar in jury and describes a fracture lin e th at en ters into the body of C2 oftentim es accompan ied by a unilateral pars fracture with m in im al displacem en t an d an gulation . Type IA in juries h ave a h igh er association with n eurologic deficit an d vertebral artery in jury because the foram en is com m only involved. These injuries, however, are typically stable. Type II in juries occur from a sim ilar m ech an ism of in jury; h owever, a subsequen t reboun d flexion in jury results in disruption of the PLL, th e C2 –C3 disk, an d often strips th e an terior lon gitudin al ligam en t off of C3. Th e result is translation and angulation of varying degrees, which can be quite large. It m ust be n oted, h owever, th at m ost of th e Type II in juries do n ot result in n eurologic in jury secon dary to th e large size of the can al at this level and by the fact that anterior displacem ent of C2 actually enlarges the canal (alth ough th e posterior rin g of C1 is brough t an teriorly an d th e posterior superior corn er of C3 is left in place, posin g an even tual risk for cord in jury). Th e m uch less com m on subcategory, Type IIA, differs from Type II in th at th e fracture lin e is oblique or m ore horizontal than the typical vertical fracture lin e of Type II an d is th ough t to result from a flexion –distraction in jury. Th ere typically is m in im al tran slation but m arked angulation secondary to the obliquity of th e fracture (Fig. 12.10). From a clin ical stan dpoin t, th e im portan ce of differen tiatin g th e two fractures lies in th e fact th at traction ten ds to distract Type IIA in juries an d sh ould be avoided, wh ereas it is th e proper treatm en t of Type II fractures. If one has a difficult tim e differentiating between th e two, in itial traction of 10 lb can be applied. If distraction occurs, th e fracture represents a Type IIA and furth er traction should be avoided. Type III fractures are th e fin al category in th e classification system an d refer to a fracture of th e pars in com bin ation with bilateral (rarely un ilateral) C2 –C3 facet dislocation . Th ese are un usual an d extrem ely un stable fracture dislocation s th at are gen erally n ot suitable for closed reduction , an d operative in terven tion is required. Associated SCI with Type III fractures is around 60%. Th e treatm en t of Han gm an ’s fractures depen ds on th e severity or type of fracture. Type I and IAfractures are stable by defin ition and can be treated successfully in a cervical orth osis. Flexion / exten sion views sh ould be obtain ed un der physician guidan ce to verify th at n o furth er displacem en t or an gulation occurs. Type II fractures are treated differen tly th an Type IIA fractures as th e latter are m ade worse with traction, although both require reduction followed by im m obilization. Type II fractures are reduced with gentle traction in extension in 5- to 10-lb increm ents (initially starting

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Subaxial Cervical Spine Trauma

Figure 12.10 Type IIa traumatic spondylolisthesis (Hangman’s

fracture). Lateral cervical spine film demonstrates angulation predominating over translation (black lines), which is pathognomonic for Type IIa C2 arch fractures. The causative flexion–distraction mechanism is thought to result in progressive tensile failure of the posterior atlantoaxial membrane (white arrow), the posterior longitudinal ligament (PLL), posterior annulus, and intervertebral disk. The anterior annulus and anterior longitudinal ligament (ALL) are thought to remain intact. (Reproduced with permission from Bucholz RW, Heckman JD, Court-Brown C, et al. Rockwood and Green’s Fractures in Adults, 6th ed. Philadelphia, Lippincott Williams & Wilkins, 2005.)

with 10 lb), followed by eith er im m ediate im m obilization in a h alo vest on ce fracture reduction is con firm ed radiograph ically or by 4 to 6 weeks of skeletal traction followed by im m obilization in a halo vest. Total treatm ent tim e is gen erally 10 to 12 weeks. Th ese fractures typically h eal by virtue of spon tan eous an kylosis of th e C2 –C3 disk space un dern eath th e an terior lon gitudin al ligam en t, wh ich h as been stripped off of th e body of C3. Altern ative treatm en t for widely displaced fractures (> 5 m m ) is prim ary osteosyn th esis utilizin g com pression screw fixation across the pars or C2 –C3 arth rodesis. Type IIA fractures can n ot be treated by traction as discussed earlier an d are subsequen tly reduced in a h alo rin g un der exten sion an d com pression with h alo-vest im m obilization for approxim ately 12 weeks. Fin ally, Type III in juries can n ot gen erally be reduced by closed m ean s, an d open reduction is n ecessary followed by fusion of C2 –C3 with prim ary osteosynthesis across th e pars or by exten sion of th e fusion to in clude C1.

Subaxial cervical spin e traum a describes in juries from th e region of C3 to th e upper border of T1. Subaxial cervical injuries account for around 70% of cervical spine traum a. As discussed earlier, when viewing radiographs of the cervical spine, it is absolutely necessary to be able to visualize the upper section of the vertebral body of T1 as fractures an d fracture dislocations in the C7 region account for 15% to 20% of subaxial cervical in juries. Subaxial cervical spin e injuries can be classified in reference to m echanism or according to anatom ic location. In 1982, Allen and Ferguson devised a classification for subaxial cervical spin e in juries on th e basis of th e m ech an ism of in jury an d th e severity of in jury. This classification helps better understan d the m echanism of in jury, fracture severity, prognosis, and treatm en t. There are six different groups: compressive flexion, vertical compression, distractive flexion , compression exten sion , distractive exten sion , an d lateral flexion . Th e descriptive classification simply divides fractures into vertebral body fractures an d facet fractures/ dislocation s am on g oth ers. Th is section will focus on th e descriptive classification but will describe m ech anism s of injury with each fracture. Of note, in juries that will not be discussed but can occur in clude isolated lam in a fractures, pedicle fractures, facet fractures (with out dislocation ), an d an terior ten sion ban d in juries.

Vertebral Body Fractures Vertebral body fractures in the subaxial cervical spine are com m on injuries whose evaluation and treatm ent differ sign ificantly from th ose of in juries to the upper cervical spin e. Variables affecting th e treatm ent include fracture pattern , associated in juries, an d n eurologic status of th e patient. Fracture patterns include compression fracture, burst fracture, an d “teardrop fracture,’’ describing a m ore unstable varian t. Not on ly does the fracture pattern guide decision m akin g, th e presen ce of m ultiple fractures at con tiguous levels, wh ich is not uncom m on ly seen, guides decision m aking as well. As with all cervical spine injuries, close attention needs to be paid to the presence/ absence of associated in juries, specifically in juries to th e posterior ligam entous structures as this renders a given fracture sign ifican tly m ore unstable. Fin ally, n eurologic status weigh s h eavily on treatm ent decision s, with particular atten tion to a declinin g n eurologic status as th is m arks an absolute reason to perform operative stabilization to prevent further deterioration . Th e m ech an ism of vertebral body fractures in volves axial compression with varying degrees of flexion producing the various fracture patterns described. Stability of these injuries is h igh ly variable as som e of these fractures are very unstable with the potential for quick neurologic deterioration . Burst fractures by defin ition result from a purely axial compression load, while compression fractures have a


flexion component with an asym m etrical compression load beginnin g in the anterior half of the vertebral body with subsequen t ten sion in g of th e posterior structures. Depen din g on th e force of th e applied load, th e an terior elem en ts can be compressed very little with overall m ain ten an ce of vertebral h eigh t, or compression can be quite significant with substantial loss of heigh t. In the sam e m an ner, ten sile forces can leave the posterior elem ents virtually with out in jury or th ey can be completely disrupted m aking the injury grossly unstable. An important concept to rem em ber is th at th e posterior elem en ts fail un der ten sion secon darily as the an terior vertebral body fails un der the initial compressive forces. Compression fractures (classified as compression flexion injuries by Allen an d Ferguson ), therefore, need to be classified as stable or unstable as there is such a vast continuum of injury characteristics. While one can gather the degree of disruption to som e exten t by physical exam ination, m ore concrete evidence is gain ed by radiograph ic studies, initially plain film s. A stable com pression fracture is generally defined as a fracture with less than 40% loss of an terior h eigh t, with out disruption of th e posterior cortex of th e body or disruption of th e posterior ligam en tous complex, in a neurologically intact patien t (Fig. 12.11).

Figure 12.11 Lateral cervical x-ray of a stable compression frac-

ture. There is minimal appreciable kyphosis, no translation, no facet joint gapping, and minimal evidence of interspinous widening. (Reproduced with permission from Bucholz RW, Heckman JD, CourtBrown C, et al. Rockwood and Green’s Fractures in Adults, 6th ed. Philadelphia, Lippincott Williams & Wilkins, 2005.)

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Stable fractures can generally be treated n onoperatively with use of a cervical orth osis on ly. Determ in ation of posterior stability can be in ferred from plain film s by th e degree of kyph osis between segm en ts. Kyph osis between segm ents greater th an 11 degrees suggests probable disruption of th e posterior elem en ts an d th erefore in stability. Oth er m arkers of posterior disruption in clude posterior ten dern ess/ecchym osis on physical exam in ation an d th e additional radiographic findings of interspinous widening or facet subluxation . CT can h elp with th e bony evaluation as well an d is alm ost always obtain ed after an in jury is iden tified. If there is still question as to whether the posterior elem en ts are disrupted or in tact, an MRI can be obtain ed to h elp guide decision m akin g. O f n ote, m ore severe compression fractures in volvin g greater than 40% of the an terior h eigh t, with intact posterior ligam en ts, in a n eurologically intact patient can be treated with a halo vest. A halo vest is typically not used for defin itive treatm ent if there is a ligam entous disruption , h owever, as a high rate of failure will en sue. Burst fractures as previously discussed result from a pure axial compression injury and are classified as vertical com pression fractures un der th e Allen an d Ferguson classification sch em e. Th ese in juries gen erally are th e result of a high-energy injury producin g posterior vertebral body com m in ution , often with a fragm en t of retropulsed bon e into the spinal can al. As such, SCIs are com m on secon dary to canal comprom ise. Since these fractures are caused by pure axial com pression , th eoretically th e posterior ligam entous elem en ts should rem ain intact. However, th ere often is som e degree of flexion , so th e posterior structures can be dam aged as the result of secondary distraction. As with compression fractures, assessm ent of stability as well as the patient’s neurologic status m ust be considered wh en discussin g optim al treatm en t. Th e in dication s for surgical treatm ent of burst fractures are less clear than oth er fractures, especially in a patien t wh o is n eurologically in tact. Absolute in dication s for surgery are in com plete n eurologic in jury, an d m ost would argue com plete n eurologic in jury, regardless wh eth er th e posterior structures are in tact if there is persistent cord compression from retropulsed bon e. Th e typical surgery in volves an terior decom pression / corpectom y with an terior strut graftin g an d fusion with or with out posterior fusion, depending on the stability of th e posterior elem ents. Th e treatm en t of burst fractures in th e patien t with n o n eurologic deficit is less clear. Th e elem en ts on e exam ines are the degree of loss of h eight, kyph otic deform ity, can al comprom ise, an d eviden ce of posterior ligam en tous disruption , wh ich are determ in ed by th e sam e fin din gs as discussed under compression fractures: interspinous widen in g, facet subluxation , an d physical exam in ation . CT evaluation is th e n orm with th ese in juries with atten tion bein g paid to th e retropulsed fragm en t of bon e an d th e am ount of can al comprom ise secondary to th e fragm ent (Fig. 12.12). Comprom ise of 20% or m ore should generally

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A

B

C

D Figure 12.12 C3 burst fracture. (A) Preoperative lateral view. (B) Preoperative axial CT scan.

(C) CT reconstruction. (D) Healing after anterior corpectomy and plating. (Reproduced with permission from Frymoyer JW, Wiesel SW, An HS, et al. The Adult and Pediatric Spine, 3rd ed. Philadelphia: Lippincott Williams & Wilkins, 2003.)


be treated operatively, with lesser degrees perh aps un dergoing nonoperative m anagem ent (provided that the patient is neurologically intact). MRI can provide further inform ation if necessary, exam ining th e cord itself as well as the posterior elem en ts. MRI sh ould n ot be ordered un less it will provide addition al in form ation to guide decision m aking. If one decides upon nonoperative m anagem ent, typical treatm ent in volves a h alo vest, or occasionally a rigid cervical orth osis. Regardless of the type of im m obilization, close follow-up is necessary to ensure that the fracture is adequately stabilized. Th e in fam ous “teardrop’’varian t of compression (Allen an d Ferguson compressive flexion Type III) fractures needs to be discussed briefly as th ere is such a h igh in ciden ce of neurologic in jury with th is fracture, an d surgery is alm ost always indicated. The m echanism of injury is the sam e as discussed earlier with compression fracture, but th ere is such a high degree of flexion with compression that an an terior fragm en t of bon e separates from th e rem ain der of th e body (an terior extrusion of a fragm en t from th e an terior lip of th e body) often with retrolisthesis of the rem ain der of th e posterior body or posterior displacem en t of th e posteroin ferior corn er of th e in volved vertebral body. Th e com m onality of neurologic injury results from the posterior displacem en t of eith er th e body or th e posteroin ferior corn er, an d as such surgery is gen erally in dicated. In the case of n eurologically intact patients, surgical decision m akin g follows th e sam e algorithm as with other types of compression fractures with close atten tion to any evidence of posterior in stability.

Facet Subluxation and Dislocation Subluxation , dislocation , an d fracture dislocation of th e facet join ts of th e subaxial spin e represen t a spectrum of injuries resulting from a m echanism of flexion –distraction with or with out an elem en t of rotation . Appropriate treatm en t of these relatively com m on injuries requires appreciation of the exact pathologic anatomy as well as the patient’s current neurologic status and the expected n atural h istory of th e in jury. Th e variation in in jury pattern s in cludes un ilateral or bilateral subluxation , dislocation , dislocation with varyin g degrees of displacem en t, an d facet fractures associated with any of the above (m ost com m only associated with dislocation). If fracture does occur, th e m ost com m on fracture pattern is that of th e superior facet of the caudad level, although fracture of th e inferior facet of the ceph alad level is seen as well. An important consideration wh en assessin g th is in jury is th e associated disruption of the ligam entous an atomy of th e spine as this determ ines stability. As with any dislocation, disruption of th e joint capsule is seen, but with these in juries, disruption of the ligam entum flavum , interspinous ligam ent, an d the PLL m ay also be present, contributing further to instability. Finally, an d m ost importantly, consideration needs to be paid to the neurologic status of the patien t. As one should expect,

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n eurologic in jury is com m on followin g th ese in juries an d correlates roughly with the degree of sagittal translation presen t sin ce th is determ in es th e SAC. Kan g et al. dem on strated th at th e risk of injury is also highly dependent on the preexisting sagittal canal diam eter of the cervical spine, wh ich is in tuitive con sidering there is very little room for the cord to displace without causing cord impin gem en t. Neurologic in jury can ran ge from isolated root deficit to complete cord injury. As m en tion ed earlier, virtually all facet in juries occur following a flexion injury, m ost com m only with distraction an d various degrees of rotation . C5 –C6 is th e m ost com m on in jury level seen, but th e possible presence of C6 –C7 an d even C7 –T1 in jury m an dates th orough radiographic evaluation down to the superior end plate of T1. In m ost cases, displacem en t is readily apparen t on lateral radiographs (Fig. 12.13) with disruption in the alignm ent of th e facet join ts. On th e AP view, offset of th e spin ous processes can som etim es be visualized depen din g on th e rotation al compon en t in volved, an d subluxation or dislocation can also be visualized on th e oblique or pillar views. CT scan n in g after iden tification of th e fracture is th e n orm , an d CT provides m ore specific in form ation in cludin g th e degree of displacem en t an d associated fractures th at m ay n ot h ave been appreciated on plain film s. MRI is also useful, especially when evaluating for the poten tial of an associated h ern iated disk as th is can cause worsening neurologic comprom ise with subsequent reduction (Fig. 12.13B). Alth ough th is risk is recogn ized, th e tim in g of MRI is difficult as th e study takes tim e to perform an d n ot all facilities have in stan t access to MRI. Th erefore, when an MRI sh ould be perform ed is an area of m uch debate. Most would agree th at an MRI sh ould be obtain ed prior to closed reduction in the patient who has a norm al exam in ation as th e risks of causin g poten tial h arm outweigh th e ben efits of im m ediate reduction wh en th e patien t is n eurologically in tact. Con versely, m ost would agree th at patien ts with a complete SCI should undergo im m ediate skeletal traction an d closed reduction an d, if un successful, sh ould then undergo MR im aging prior to determ in ation of definitive in terven tion . Th ese patien ts already h ave a complete in jury an d ben efit from decom pression as soon as possible. Th e difficult patien t population is th ose with an in complete in jury wh o would ben efit m ost from urgen t reduction but at th e sam e tim e are at risk for furth er n eurologic deterioration . Most would agree th at th ese patien ts sh ould un dergo skeletal traction and closed reduction rather than await MRI provided th ey are awake, alert, an d can cooperate with serial exam inations. The patient can th en provide feedback durin g th e reduction so th at any sign s of n eurologic worsen in g can be n oted, at wh ich tim e closed reduction sh ould be ceased. Any eviden ce of n eurologic worsen in g durin g reduction sh ould result in n euroim agin g an d treatm en t as in dicated. If closed reduction is un successful in a patien t with an in complete SCI, MRI is obtain ed prior to any attempt at open reduction . If at any poin t alon g th is algorith m a disk

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A

B Figure 12.13 Bilateral facet subluxation. (A) Lateral plain film. (B) Postreduction MRI shows a

herniated disk present. (Reproduced with permission from Bucholz RW, Heckman JD, Court-Brown C, et al. Rockwood and Green’s Fractures in Adults, 6th ed. Philadelphia, Lippincott Williams & Wilkins, 2005.)

hern iation is appreciated on MRI, its significan ce m ust be assessed. Of n ote, plain film s can pick up a m assive, clin ically significant disk herniation by a complete loss of disk height on the lateral radiograph. On MRI, th e presen ce of an extruded disk fragm en t posterior to th e posteroin ferior corner of the cephalad vertebral body, a relatively rare occurrence, represents a risk following closed reduction and sh ould therefore be addressed. An terior discectom y is carried out in this setting prior to any reduction, followed by reduction , fusion , an d stabilization , gen erally an teriorly, but som etim e via a com bin ed approach . Given the foregoin g considerations, th e diagnosis of a facet subluxation or dislocation requires reduction an d stabilization . In th e presen ce of a n eurologic deficit, oth er than an isolated n erve root in jury, reduction is an em ergen cy an d is obtain ed with th e application of skeletal traction with skull ton gs. O n ce reduction is obtain ed, stabilization can be carried out m ore electively, usually in th e first 48 to 72 hours after the injury. Failure to achieve a closed reduction in a patien t with a n eurologic in jury m erits urgen t open reduction an d stabilization . Neurologic con sideration s aside, th e optim al m ean s of stabilizing these injuries depen ds on th e spectrum of softtissue an d bony in jury presen t. Non operative treatm en t plays a very lim ited role an d is reserved for th ose with a m ild subluxation , a un ilateral dislocation with un rem arkable n eurologic exam in ation (th ese we gen erally recom m en d for operative treatm en t), an d th ose wh o are too sick to un dergo operative treatm en t. Non operative treatm en t in volves a cervical orth oses for a period of 10 to 12 weeks as h alo-vest im m obilization h as been sh own to be m uch less reliable th an in th e upper cervical spin e. Halo-vest im m obilization h as a h igh risk of redisplacem en t because of

paradoxical m otion of th e subaxial vertebral bodies. Because of th e risk of redisplacem en t, even un ilateral dislocation s are gen erally treated by operative m ean s as th ere is n ot a good m ethod of adequately im m obilizin g th e injury n onoperatively. Bilateral facet dislocation s com m on ly occur in conjunction with significant disruption of the interspinous ligam ent, ligam entum flavum , and often the PLL and are th erefore h igh ly un stable. Ligam en tous disruption with un ilateral facet dislocation is gen erally less severe, with th e PLLspared m uch m ore com m on ly. Th is con stitutes th e reason why som e surgeon s attempt to treat unilateral dislocations nonoperatively. Our preferen ce for either injury is surgical stabilization due to the in consistent results following n onoperative m anagem en t an d th e un stable n ature of the injuries. With operative m an agem ent, the neurologically n orm al patien t is return ed m uch m ore quickly to norm al activity with m in im al risk of long-term sequelae, while the n eurologically impaired patien t is ready to aggressively un dergo reh abilitation followin g surgery with out th e n eed for prolon ged extern al im m obilization . O perative treatm en t involves stabilization and fusion, which can be done anteriorly, posteriorly or with a com bin ed approach an d depen ds on associated in juries (i.e., herniated disk treated with discectomy an d an terior fusion , gen erally). With n o n eurologic in jury or n o n eed for rem oval of elem ents from th e can al, a posterior approach is gen erally used.

Thoracolumbar Trauma Th oracolum bar in juries en compass in juries from T1 to L5 an d range in severity from m ild to life threatening. The initial m anagem ent has been covered in th e previous sections


but in cludes in itially followin g ATLS protocol with specific attention paid to the protection of the spin al colum n . A thorough physical exam in ation sh ould be perform ed with particular atten tion to n eurologic deficits followed by appropriate radiograph ic exam in ation . All patien ts with suspected th oracolum bar traum a sh ould in itially receive at least an AP and lateral of the entire region with close in spection at each level. If there is any question about th e injury following plain film s, or if a closer exam ination is needed, CT is obtain ed for further evaluation. Addition ally, MRI is utilized if there is any neurologic deficit, a need to evaluate ligam en tous disruption , an d/or before surgical interven tion . This section will focus on specific injuries and injury patterns. Th ere are m any classification sch em es for th oracolum bar in juries, an d as on e m igh t expect, n on e are un iversally agreed upon. Th erefore, the classic and easiest way to discuss these in juries is by a descriptive classification based on th e th ree-colum n th eory of th e th oracolum bar spin e popularized by Den is in 1983 (Fig. 12.1). Th e an terior colum n con sists of th e ALL an d th e an terior two-th irds of th e vertebral body; the m iddle colum n consists of the posterior on e-th ird of th e vertebral body; th e posterior colum n con sists of th e rem aining posterior structures includin g the facet joints, interspinous ligam en t, supraspinous ligam en t, and the ligam entum flavum . As discussed previously, Den is defin ed in stability as disruption of at least two colum n s. In the following sections, these colum ns will be referred to wh en discussin g in jury pattern s an d m ech anism s of injury. The injuries will be divided in to compression fractures, burst fractures, flexion –distraction in juries (Chance injuries), and fracture dislocations.

Compression Fractures Compression fractures m ake up the m ajority of traum atic injuries to th e thoracic and lum bar spin e, even after path ologic fractures th rough osteoporotic bon e h ave been excluded. Th e m ech an ism of in jury in volves axial com pression com bin ed with m ild degrees of forward flexion producin g com pressive failure of th e an terior aspect of th e vertebral body (Denis’s anterior colum n). By definition , a compression fracture involves only the an terior colum n with preservation of th e m iddle an d posterior colum n s. Th e isolated involvem ent of the an terior colum n differentiates them from burst fractures, which result in compression of the m iddle colum n as well. Compression fractures generally result from low-en ergy traum a in th e elderly but can be secon dary to m uch h igh er-en ergy m ech an ism s in th e younger population . True compression fractures represent stable in juries; however, m any tim es it is difficult to differen tiate a com pression fracture from its m ore serious coun terpart, th e burst fractures, or even a flexion –distraction injury, involving ten sion failure, or distraction, of the posterior elem en ts. Differen tiation of th ese in juries is im portan t as m ore serious injuries often require surgical intervention, while

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compression fractures can generally be treated non operatively. Th e differen tiation lies in th e radiograph ic exam in ation . On th e lateral view, loss of h eigh t of th e an terior colum n an d th e degree of kyph osis sh ould be assessed with true com pression fractures h avin g less th an 40% loss of h eight, an d less th an 30 degrees of kyph osis, m aking th em stable (Fig. 12.14). Many still consider fractures with loss of h eigh t greater th an 50% to be compression fractures if on ly th e an terior colum n is in volved; h owever, with th is am oun t of loss of h eigh t, it can be argued th at th e posterior colum n is disrupted and by definition sh ould be considered a flexion –distraction in jury. Addition ally, kyph osis greater th an 30 degrees represents an unstable fracture with likely disruption of the posterior elem ents to som e exten t. Of n ote, an addition al fin din g on th e lateral film that is suggestive of a burst fracture rather than a compression fracture is an in crease to greater than 100-degree an gle between th e superior en d plate an d th e posterior cortical lin e at th e posterosuperior corn er of th e vertebral body. In crease in th is an gle indicates probable loss of height in the m iddle colum n . On th e AP view, an in crease in in terpedicular distan ce suggests disruption of th e posterior cortex, splayin g of th e pedicles, and the presen ce of a burst fracture. If th ere is any question regardin g th e differen tiation , a CT scan sh ould be obtain ed as th ere can be disastrous con sequen ces for m isdiagnosis and subsequent m istreatm ent. Ballock an d colleagues reported a m isdiagn osis rate of 25% in attemptin g on plain radiography to differen tiate com pression fractures from burst fractures an d recom m en ded the routine use of CT scannin g in the case of compression fractures to avoid this error. If after physical exam ination, plain film s, an d CT scan n in g, on e is still un certain of posterior ligam entous stability, an MRI can be obtained to evaluate th e soft tissue stability of th e posterior colum n . Of n ote, physical exam in ation fin din gs suggestive of tension failure of the posterior colum ns, and by defin ition, not a simple compression fracture (rather a flexion distraction in jury), in clude m arked m idlin e ten dern ess at fracture site, ecchym osis, or a palpable gap between spin ous processes as in th e cervical spin e. Most compression fractures do not result in n eurologic in jury. However, compression fractures, particularly in th e upper th oracic spin e between T2 an d T10, can result in n eurologic comprom ise. Alth ough th e rib cage and stern um provide an added degree of stability to fractures in this region, th eir presence should be un derstood to imply an even greater degree of en ergy required to produce th e in jury. Th is factor, in addition to th e relatively low spin al canal–spin al cord ratio in the m idth oracic spin e, as well as th e sen sitivity of th e spin al cord to m in or traum a, all contribute to a sign ifican t risk of in jury at this level. As m en tion ed previously, com pression fractures can generally be treated nonoperatively, as they are by Denis’s defin ition stable because on ly on e colum n is disrupted. Non operative treatm en t gen erally con sists of an extern al orth osis prescribed for 2 to 3 m on th s for m ost patien ts

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Figure 12.14 Stable L3 compression

A

with close radiograph ic follow-up. Those patients with less than 10% loss of vertebral height can be treated without extern al support. Th ese in juries n eed to be followed closely with radiographs to en sure th at furth er loss of h eigh t does not occur. Finally, those fractures with greater th an 50% loss of h eigh t an d/ or greater th an 30 degrees of kyph osis sh ould be treated operatively with posterior stabilization.

Burst Fractures Sir Fran k Holdsworth was th e first to use th e term “burst fracture’’ to describe what is today recognized as one of the m ost com m on injuries to the thoracolum bar spine an d on e wh ose treatm en t con tin ues to be h otly debated. Part of the reason for the con fusion surrounding the treatm en t of burst fractures stem s from differen ces in defin ition s am on g various auth ors. Most reports are con sisten t with Holdsworth ’s origin al description of a fracture that results from th e ceph alad disk exploding through th e upper en d plate in to th e vertebral body, causin g a fracture of both the anterior an d posterior cortices. Therefore, with burst fractures one observes compression of both the anterior an d m iddle colum n , as opposed to compression fractures in wh ich on ly th e an terior colum n is disrupted. Secon dary to th e m ech an ism an d usual h igh -en ergy in jury, th ere is typically a retropulsed burst fragm en t extruded in to th e can al at the level of th e pedicles, often causin g n eural el-

B

fracture. AP (A) and lateral (B) radiographs showing a stable compression fracture. (Reproduced with permission from Bucholz RW, Heckman JD, CourtBrown C, et al. Rockwood and Green’s Fractures in Adults, 6th ed. Philadelphia, Lippincott Williams & Wilkins, 2005.)

em en t compression an d n eurologic in jury. Most surgeon s agree with Denis wh o noted that th e posterior colum n is eith er in tact in a burst fracture or sustain s a green stick-type fracture of the lam ina or spinous process but that tension failure of th e ligam en tous com pon en ts of th e posterior colum n is n ot presen t. Radiograph ic evaluation of th ese in juries is sim ilar to th at described in th e previous section for com pression fractures, with m ost of the in form ation gathered from plain film and CT. O n plain film s, one looks for the extent of loss of vertebral height, whether the loss is both anteriorly an d posteriorly in th e vertebral body, an d th e acute kyphotic angulation. Addition ally, with CT scan, one can also determ ine the presence of a retropulsed fragm ent, the exten t of can al comprom ise as a percen tage of th e cross sectional area (which m any will base a surgical decision upon ), th e presen ce of a lam in ar fracture, an d th e in tegrity of th e facet join ts (Fig. 12.15). Fin ally, th e exten t of posterior soft-tissue in jury can be evaluated with MRI, wh ich h elps m any surgeon s to decide upon operative versus n onoperative treatm en t. After taking all of these radiographic m easurem ents into accoun t as well as the patient’s n eurologic status, one tries to decide upon fracture stability an d hence operative versus non operative m an agem en t. It is the topic of stability wherein the confusion an d disagreem ent lies with this


A

B

C

D

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Figure 12.15 Burst Fx L1. This patient was a 19-year-old female who sustained a burst fracture

of L1 following an MVA. (A,B) The fracture on CT scan was judged to compromise about 60% of the canal diameter. (C,D) Notice the large fragment seen on the CT scan at L2. By proper examination and sagittal reconstruction via CT scanning, this fragment was noted to still be in continuity with L1 and as such did not have to be removed during surgery as it reduced to L1 with height restoration. (Reproduced with permission from Chapman MW. Chapman’s Orthopaedic Surgery, 2nd ed. Philadelphia, Lippincott Williams & Wilkins, 1993.)

particular in jury. Holdsworth origin ally defin ed th e burst fracture as a stable injury because of the slight risk of progressive deform ity an d n eurologic deficit. Den is, on th e oth er h an d, utilizin g h is th ree-colum n th eory, would defin e all burst fractures as un stable sin ce two of th e th ree colum n s are disrupted. McAfee and colleagues in 1982 proposed criteria for an un stable burst fracture, in cludin g a progressive n eurologic deficit, disruption of th e posterior

ligam en tous complex (wh ich m any auth ors feel would exclude such an in jury from classification as a burst fracture), acute kyph osis greater th an 20 degrees with a n eurologic deficit, 50% loss of vertebral h eigh t in th e presen ce of facet join t subluxation , an d/ or th e presen ce of retropulsed bon e causing neural elem ent comprom ise in association with an in complete n eurologic in jury. Bradford an d McBride h ave stressed, on th e other h and, the importance of a neurologic

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deficit as a clin ical in dicator of in stability at least as it pertain s to th e appropriaten ess of surgical stabilization . Though there rem ain s a great deal of con troversy surroun din g th e appropriate m an agem en t, m ost auth ors favor surgical decompression an d fusion for th e patien t wh o is n eurologically impaired, an d all would agree on surgical in terven tion for th e patien t with an in complete n eurologic in jury as decompression h as been sh own to h ave favorable results with n eurologic improvem en t. Patien ts with com plete n eurologic in jury are com m on ly treated surgically to facilitate early return to reh abilitation . In gen eral, patien ts requirin g decompression are treated with an an terior approach to adequately decompress th e cord followed gen erally by strut graftin g, stabilization (gen erally an teriorly), an d fusion . Lam in ectomy alon e does n ot con tribute to decompression of the cord or cauda equine in the presence of a burst fracture. Surgery is n ot reserved on ly for th ose with a n eurologic deficit, h owever. In th e patien t wh o is n eurologically in tact, on e m akes th e decision of surgical in terven tion on radiograph ic fin din gs th at suggest structural in stability. As alluded to earlier, th ere are n o con crete rules statin g wh en to operate an d wh en n ot to operate. However, we will provide som e gen eral radiograph ic fin din gs th at would sway m ost surgeon s toward operative in terven tion in th e patien t who is neurologically in tact. Th ese include acute kyph otic an gulation of 25 to 30 degrees or greater th an th e n orm at a particular level, greater th an 50% loss of vertebral height, greater than 50% comprom ise of the spin al can al by retropulsed bony fragm ent(s), and tension failure of the posterior ligam en tous complex. Th e n eurologically n orm al patien t wh o un dergoes surgery for poten tial in stability is usually treated posteriorly with posterior in strum en tation an d fusion . In gen eral, th e posterior approach is less m orbid th an th e an terior approach with fewer serious com plications. However, posterior in strum entation provides less support th an anterior instrum entation as it is un able to recon stitute th e an terior support. Th erefore, posterior in strum entation is m ore likely to fail with increasing kyph osis/com pression, especially in fractures with severe kyphosis and/ or loss of height. Success rates h ave been sim ilar when comparing an terior an d posterior instrum entation s an d fusion for burst fractures. Followin g th e tren d with th e treatm en t of burst fractures, the num ber of levels fused varies from surgeon to surgeon. Prior to pedicle screw fixation , Harrin gton rod in strum en tation was m ostly used with in strum en tation an d fusion three levels above and two or three levels below the fractured vertebrae. As th is requires a fairly exten sive fusion , th e adven t of pedicle screw fixation h as allowed better th reepoin t fixation , an d h en ce less levels n eeded for fusion . Curren tly, m ost surgeon s advocate pedicle screw fixation an d fusion either one or two levels (our personal preference) above an d on e or two levels below th e compression fracture depen din g on th e severity of th e fracture an d associated ligam en tous disruption . An oth er option is addin g an terior

instrum entation and fusion, and th erefore, less need for fusion m ore than one level above and one level below as th e con struct is m ore stable.

Chance Injuries In 1948, G.Q . Ch an ce provided th e first description of an injury to the lum bar spine involving flexion and distraction of th e posterior elem en ts, wh at we kn ow today as Ch an ce fractures or in juries. The m ost com m on cause of flexion – distraction in juries today are lap belt in juries from MVAs, even th ough Ch an ce’s origin al description predated th e use of lap belts. Th e lap belt scen ario, alth ough n ot always th e cause, helps on e to visualize and un derstand the m echan ism of injury an d th e forces in volved. Followin g an MVA, the individual sitting in the back seat is wearin g a lap belt an d the sudden deceleration injury forces the patient forward over the lap belt. The lap belt causes blunt traum a to th e abdom in al viscera in its course to th e spin e as th e victim continues to m ove forward. Th e belt essentially acts as a fulcrum over which the spine rotates around an axis of rotation cen tered on th e an terior cortex or an terior lon gitudinal ligam en t of the spin e. The classic description is a pure flexion –distraction in jury, but th ere often is a rotational component to it as well. As one would im agine, there is a very high rate of associated abdom inal in juries, quoted around 50%, which one needs to keep in m ind when evaluatin g lap belt in juries from eith er th e orth opedic or th e traum a surgery standpoint. Patients will typically present with th e “seatbelt sign ’’ with a ban d of ecchym osis across the abdom en wh ere the patient hinged over the belt during deceleration . Th e stan dard Ch an ce in jury m ay be a pure bony in jury, exten din g th rough th e spin ous process, lam in a, pedicle, an d vertebral body; a pure soft-tissue in jury, exten ding through the in terspin ous ligam ent, ligam en tum flavum , facet join t capsule, an d disk; or m ixed, with variable in volvem ent of bon e and soft tissue (Fig. 12.16). Th e com m on finding am ong all three is the m arked distraction of the posterior elem ents, m oderate distraction of the m iddle colum n , an d classically a neutral appearance of the far anterior colum n , reflectin g an in stan tan eous axis of rotation in or about the ALL (Fig. 12.17). It is not uncom m on to see m ild-to-m oderate wedging of the vertebral body reflecting an elem ent of axial loading in addition to pure flexion. Burst-type fractures of th e vertebral body m ay also be seen , reflectin g a m ech an ism of in jury th at ch an ges from axial loading to sudden flexion such as in a fall from a height. Neurologic in jury is un com m on but n ot rare in in juries of th is type. As with oth er areas of th e spin e, th e presen ce of a n eurologic in jury is in itially treated with realign m en t eith er th rough an operative or n on operative approach , followed by stabilization. Reduction involves various hyperexten sion m an euvers. If th e patien t recovers n eurologic status followin g reduction, the treatm ent can then be operative or n on operative, but in th at situation , m ost surgeon s would likely elect operative intervention for reliable stability. If

B

A

Figure 12.16 Chance fracture. (A) Pure soft-

tissue injury. (B) Pure bony chance fracture. (C) Mixed injury. (Reproduced with permission from Frymoyer JW, Wiesel SW, An HS, et al. The Adult and Pediatric Spine, 3rd ed. Philadelphia: Lippincott Williams & Wilkins, 2003.)

C

A

B

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Figure 12.17 Radiographic characteristics of Chance injury. (A) Lateral radiograph of a severe

flexion–distraction injury status post MVA. (B) AP radiograph shows wide spacing between spinous processes at the level of the injury. (C) MRI confirms extensive soft-tissue disruption. (Reproduced with permission from Frymoyer JW, Wiesel SW, An HS, et al. The Adult and Pediatric Spine, 3rd ed. Philadelphia: Lippincott Williams & Wilkins, 2003.)

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after reduction , th e patien t m ain tain s a n eurologic deficit, suggestin g continued compression on either the cord or th e cauda equina, form al operative decompression sh ould be perform ed, usually from a posterior approach . Ch an ce in juries are h igh ly un stable an d are th erefore n ot am en able to an terior stabilization as th e disruption occurs posteriorly. If an terior decom pression is required, a circum feren tial approach is recom m en ded. Preoperative CT an d MRI are recom m en ded to furth er evaluate th e fracture, to recognize all associated injuries, an d to evaluate the possibility of a h ern iated disk protrudin g in to th e can al as th is m ay require an terior decompression . The treatm ent for the patien t who is neurologically in tact depen ds on th e type of in jury, th at is, bony, ligam en tous, or m ixed. Pure bony Ch an ce fractures are am en able to n on operative treatm en t provided on e can m ain tain reduction th rough bracin g or castin g. Th ese ten d to h eal well as bony un ion can be obtain ed in currin g stability to th e spin al colum n. These injuries are by definition unstable as ten sion failure h as occurred posteriorly. Reduction is accomplished through hyperextension and then m aintained through hyperextension casting or bracin g. Casting is m ore reliable as complian ce is n ot an issue. If th ere is any worry about m ain ten an ce of reduction , on e sh ould proceed to operative in terven tion . The m ajority of the in juries are not pure bony chan ce fractures, and as such , nonoperative intervention is likely to fail, sin ce ligam en tous h ealin g in th e spin e is suboptim al. Pure ligam en tous in juries, or prim arily ligam en tous in juries, sh ould be stabilized operatively. Again , preoperative CTscan n in g an d MRI are warran ted to fully evaluate th e in jury an d look for th e possibility of a h ern iated disk. Provided th ere is n o h ern iated disk to suggest a n eed for an terior decompression, a posterior approach is recom m en ded as th e prim ary m ode of in jury is distraction th rough th e posterior elem en ts. With a pure flexion distraction in jury with no involvem en t of com pression at the anterior colum n , spin al in strum en tation in th e form of pedicle screw fixation an d a sin gle-level fusion is employed. If th ere is an elem en t of an terior com pression , m ore complicated m easures m ay h ave to be employed in the form of a th ree-poin t ben din g type of system to restore lordosis with a touch of distraction to restore h eigh t. O f n ote, distraction in m ost flexion –distraction in juries is in appropriate as th is will in crease the distraction between the posterior elem ents.

Fracture Dislocation of the Thoracolumbar Spine Th e m ost om in ous an d m ost un stable of all in juries of th e thoracolum bar spine is th e fracture dislocation. There are num erous m echanism s depending on th e resultan t dislocation, but the hallm ark of all in juries is translation in the coronal and/ or sagittal plan es. If translation, even when m ild, is observed eith er on th e AP or lateral radiograph , its importan ce sh ould n ot be overlooked. As with any dislo-

cation or subluxation , th e displacem en t of th e spin e m ay be reduced by th e tim e of radiograph ic assessm en t, an d m ay therefore be m issed, which underscores the importan ce of takin g a careful look at even th e m ildest of tran slation s, since fracture dislocations are serious injuries with life-threatening consequences when m issed. Fracture dislocation s of th e spin e are h igh -en ergy in juries resultin g in extrem ely un stable fracture pattern s with a high rate of associated severe n eurologic deficits. As alluded to earlier, a com bination of m echanism s of injury occur in cludin g flexion , exten sion , rotation , compression , and sh ear (Fig. 12.18). A few of the classic m echanism s will be discussed later, but keep in m in d th at th is is n ot an all-inclusive set of m echanism s. Holdsworth first described the “slice fracture,’’ referring to a flexion-rotation injury at the thoracolum bar junction with translation in both th e AP an d lateral plan es, an d frequen tly paraplegia. Translation is the m ost striking feature radiographically an d m ay be associated with fracture of th e vertebral body an d/ or facet fracture. In th is in jury, th e ALL is usually intact, although it is typically stripped off of the anterior aspect of th e in ferior vertebral body. An oth er com m on m echan ism is the severe variant of the flexion –distraction injury discussed in the previous section, differentiated by translation , typically seen only on the lateral radiograph, wh ich can be severe at tim es. Th e m ech an ism is typically th e sam e an d can in volve an elem ent of rotation (as can Ch ance injuries) as well. Th e ALL again is usually intact but m ay be stripped off of th e an terior aspect of the in ferior vertebral body as well. Th e im portan ce of distin guish in g between th e stan dard flexion –distraction in jury an d th e m ore severe fracture dislocation varian t lies in the greater extent of en ergy in volvem en t, th e greater risk for n eurologic in jury, and the greater degree of in stability seen with fracture dislocations. Therefore, again, one needs to pay close attention to any degree of translation. The final m echan ism of injury th at will be discussed in volves a pure tran slation al force applied to th e spin e in th e form of hyperexten sion an d sh ear forces, typically at the thoracolum bar jun ction. The classic exam ple is the lum berjack that is struck directly on the back by a fallin g log. Th ese sh ear-type in juries are th e m ost un stable varian t of th e fracture dislocation s as th ey typically in volve failure of th e ALL ren derin g th e spin e grossly un stable. As expected, th ese in juries h ave a very h igh rate of associated n eurologic deficits. To fully appreciate th e in jury, on e n eeds to un derstan d th e path oan atom y of th e region , wh ich will h elp with th e proper reduction m an euvers n eeded. Th e th oracolum bar jun ction is th e m ost frequen tly in volved region because it represen ts a transition zon e between the stable th oracic region en closed by th e rib cage an d th e m obile lum bar region . Th ere is also a tran sition between th e orien tation of th e th oracic facet join ts to th e lum bar facet join ts, furth er ren derin g th is region pron e to in jury. Upon presen tation, one should follow th e guidelines laid out for all spinal traum a, and atten tion needs to be


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A

Figure 12.18 Fracture dislocations. (A) Flex-

ion rotation. (B) Shear. (C) Flexion–distraction. (Reproduced with permission from Frymoyer JW, Wiesel SW, An HS, et al. The Adult and Pediatric Spine, 3rd ed. Philadelphia: Lippincott Williams & Wilkins, 2003.) (Continued )

paid to th e serious associated in juries with fracture dislocations includin g traum a to the thorax, m ediastinum , an d abdom en, as well as blunt traum a to the aorta. Neurologic injury is the norm that un fortun ately is frequently complete or n ear-com plete resultin g in paraplegia. Dural tears occur around half of the tim e as well. Careful evaluation of sacral sparing should be carried out. Radiographic evaluation begins with stan dard AP an d lateral radiographs followed by CT scann ing with sagittal and coronal reconstructions and MRI evaluation once th e injury is iden tified. As stressed earlier, recognition of this very serious injury stem s from recogn izing the radiograph ic hallm ark, tran slation. Once the diagn osis is m ade, all of these fractures require operative stabilization as all th ree colum n s are disrupted an d thus the only stability th at is m ain tained is by the ALL if it is intact. These represen t the m ost unstable of all spin e in juries, an d patien t m obilization for im proved pulm on ary fun ction an d gen eral m edical care in these patients sh ould be deferred until definitive treatm ent of th e spin e is perform ed. Th erefore, th ese in juries sh ould be defin itively stabilized as soon as possible, preferably

B

in th e first 48 h ours after in jury. Because of th e in h eren t in stability of th ese in juries, it is importan t to accept that rigid segm ental instrum entation should be employed an d strategies design ed to m in im ize th e n um ber of levels fused that are used with other injuries are generally inappropriate for th ese cases. Most advocate lon g fusion s exten din g th ree levels above an d at least two, if n ot th ree levels below th e fracture with pedicle screw in strum en tation . Th ere are reports of less aggressive fusion with good results; h owever, lon g fusion is still recom m en ded. Oth er m eth ods aside from pedicle screw fixation an d in strum en tation in clude sublam in ar wirin g, in terspin ous wirin g, an d segm ental an d n on -segm ental hook fixation. These m ethods are often com bin ed with an terior in strum en tation to obtain even m ore stability. Reduction sh ould be obtained in all cases, even in complete n eurologic injury, as anatom ic reduction restores significant in h erent stability an d thus lessens the stress on surgical im plan ts and m ay contribute to a lesser degree of postoperative pain . Addition ally, th ere still exists th e rem ote possibility of som e degree of n eurologic recovery.

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C

Figure 12.18 (continued )

In cases of in complete n eurologic in jury, reduction is the prim ary m ean s of decompression and should be accomplish ed expeditiously. Stabilization is carried out, an d th e patien t is th en reassessed for any persisten t can al comprom ise an teriorly. Th e presence of persistent bon e or disk in th e can al can th en be treated th rough a separate an terior approach with structural an terior graftin g to m ain tain h eigh t. In gen eral, th ese h igh ly un stable in juries are n ot am en able to an terior stabilization alon e, an d it is therefore our preference to proceed with reduction an d rigid fixation through a posterior approach prior to any consideration for an terior surgery.

Spon dylosis (osteoarth ritis) is th e tech n ical term th at describes th e sequen ce of degen erative ch an ges th at occurs th rough out th e spin e with in creasin g age. Everyon e develops spon dylosis, but on ly a subgroup will com plain of symptom s. Th e physician n eeds to accurately diagn ose th e specific etiology for each patien t an d prescribe th e appropriate treatm en t. Th is section will focus on degen erative con dition s in th e cervical, th oracic, an d lum bar spin e. In each area, th e appropriate h istory, physical fin din gs, an d diagn ostic studies will be reviewed. Addition ally, an algorith m will be described for the treatm en t of cervical and lum bar conditions.

DEGENERATIVE DISORDERS OF THE SPINE

CERVICAL SPINE

A m ajor proportion of th e adult population is affected by degen erative con dition s of th e spin e. Th ese disorders h ave a m ajor impact on the cost of health care delivery. Every physician sh ould h ave a workin g kn owledge of th ese path ologic con dition s an d sh ould be able to recogn ize a serious problem wh en it arises. In both the cervical spine (myelopathy) an d th e lum bar spin e (cauda equin a com pression ), disastrous sequelae such as paralysis can occur if th ese are overlooked.

Before discussin g in dividual en tities of th e cervical spine, we will first discuss th e h istory an d physical exam in ation of th e cervical spin e followed by section s on th e defin ition , symptom s, and physical exam in ation fin dings of radiculopathy an d m yelopathy th at often occur in con jun ction with m any cervical spin e degen erative con dition s. Additionally, we will discuss com m on conditions that can presen t with radiculopathy an d myelopathy. In th e section s followin g the radiculopathy an d myelopathy overviews,


individual disease entities will be discussed in further detail.

History and Physical Examination Prior to th e physical exam in ation of th e cervical spin e, a thorough history should be obtained with specific focus on sym ptom s (pain , n um bn ess, etc.), len gth of tim e of th e symptom s, radiation of th e symptom s, quality, associated symptom s, h istory of traum a, an d wh ether the con dition has been progressive. On ly after a careful history has been obtain ed, on e sh ould m ove to th e actual physical exam ination. The m ajority of the tim e the diagnosis can be m ade with h istory alon e an d th e physical exam in ation is used to con firm th e diagnosis. As with th e physical exam ination on any portion of the body, th e physical exam in ation of th e cervical spin e sh ould be con ducted in a structured, system atic way, th us allowin g efficien cy an d compreh en siven ess. In spection is th e first step, lookin g for asym m etry, m uscular atrophy, and in juries (ecchym osis, lacerations, etc.), especially when discussing traum a, in not only the cervical spin e but also in th e shoulders, arm , an d forearm s. Atrophy in a specific m uscular group m ay be a sign of n erve root im pin gem en t, wh ereas abrasions/ ecchym osis would lead the exam iner down anoth er path . Palpation follows in spection, with careful atten tion to any areas of bony ten derness and step-off between spinous processes (especially in traum a). Paraspin al ten dern ess is quite com m on an d m uch less specific an d less worrisom e for a severe injury than bony ten derness. Bony ten derness or step-off warrants a radiograph ic workup, wh ereas paraspin al ten dern ess often does n ot. Followin g palpation , a careful n eurologic exam in ation sh ould be perform ed with a th orough m otor, sensory, and reflex testin g. Th e m otor exam in ation gen erally provides the m ost specific inform ation, so it is important to isolate each m yotom e an d test each area in dividually. Com parison of both sides is vital as well. Muscle strength is graded on a scale from 0 to 5 with 5 represen tin g n orm al stren gth , 4 represen tin g stren gth again st resistan ce but n ot n orm al, 3 represents m ovem ent again st gravity only, 2 represents m ovem en t with gravity taken out of th e equation, 1 represen ts evidence of contraction but no active m ovem en t, an d 0 represen ts n o eviden ce of con tractility. Followin g th e m otor exam in ation , sen sation sh ould be tested in all derm atom es with specific atten tion to wh eth er there is a level below which testing becom es abnorm al. Th e sen sory exam in ation is m uch less specific th an th e m otor exam ination, although it does provide additional helpful inform ation . Following the sensory exam in ation , deep ten don reflex testin g sh ould be don e; th is essen tially con sists of th e biceps (C5/6), brachioradialis (C6), and triceps (C7). Th e Hoffm an’s test (an upper m otor neuron test) sh ould also be don e, wh ich , if positive, sh ows eviden ce of a m yelopath ic picture.

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After careful focus in th e upper extrem ities, th e lower extrem ities n eed to be exam in ed as well because cervical spin e myelopathy usually h as positive findings in the upper an d lower extrem ities. Specifically, th e patien t’s gait sh ould be observed, wh ich is classically described as a wide, broadbased gait with myelopathy. Addition ally, stren gth an d reflex testing sh ould be exam ined. The m ost com m on abnorm al lower extrem ity myelopath ic sign s are weakn ess, spasticity, an d hyperreflexia. O n e m ay fin d a positive Babin ski’s sign as well with myelopathy. Finally, atrophy can be observed in the lower extrem ities but is less com m on and den otes a m uch longer stan din g problem . As will be discussed in th e n ext section s, myelopathy ten ds to affect th e upper an d lower extrem ities, wh ile radiculopathy on ly affects th e upper extrem ities; th us, th e lower extrem ity exam in ation sh ould be n orm al in th e face of a pure radiculopathy.

Cervical Radiculopathy Cervical radiculopathy is defined as pain or symptom atology in th e distribution of on e of th e cervical roots. Th is is typically radiatin g pain from the n eck into the arm , alth ough th e classic derm atom al distribution is n ot always seen. It is caused by compression of a cervical nerve root, gen erally as it exits from th e spin al cord, wh ich can be secon dary to a variety of reason s ran gin g from h ern iated disks to degenerative changes. It is th e compression of the nerve itself that differen tiates radiculopathy from myelopathy, wh ich is compression of th e cord as a wh ole rath er th an of an individual nerve root.

History Patien ts will gen erally presen t secon dary to pain in th e n eck region th at radiates in to th e arm . Th is radiatin g pain from th e n eck in to th e arm is th e h allm ark of radicular pain . Th e patien t typically describes th e pain as sh ootin g, burn in g, or a deep ach e. Many tim es, th ey will describe paresth esias down th e arm as well. It m ust be n oted, h owever, th at th ere are radiculopathies that radiate no further th an the shoulder, an d th e predom in atin g com plain t of patien ts will be sh oulder pain rath er than the classic presen tation. Physical Examination Wh en dealin g with th e physical exam in ation for a suspected radiculopathy, th e typical exam in ation of th e cervical spine should be done as previously discussed, with specific atten tion on certain parts of the physical exam ination. As m entioned earlier, the un derlying abnorm ality is irritation on the affected root from a site of compression. Keepin g th is in m in d, th ere are m an euvers described th at further irritate the nerve to elicit the patient’s symptom s. Th e classic test is Spurlin g’s sign . In th is test, th e patien t’s h ead is flexed laterally, sligh tly rotated toward th e symptom atic side, an d then compressed to elicit reproduction or aggravation of th e radicular sym ptom s. An oth er test described th at h as the opposite effect is the abduction relief

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TABLE 12.1

CERVICAL RADICULOPATHY C2–C3 Disk: C3 Nerve Root Pain: Back of neck, mastoid process, pinna of ear Sensation: Back of neck, mastoid process, pinna of ear Motor: None Reflex: None

C5–C6 Disk: C6 Nerve Root Pain: Neck, shoulder, medial scapula, lateral arm, dorsal forearm Sensation: Thumb and index finger Motor: Biceps, wrist extension Reflex: Brachioradialis

C3–C4 Disk: C4 Nerve Root Pain: Back of neck, levator scapula, anterior chest Sensation: Back of neck, levator scapula, anterior chest Motor: None Reflex: None

C6–C7 Disk: C7 Nerve Root Pain: Neck, shoulder, medial scapula, lateral arm, dorsal forearm Sensation: Index and middle fingers Motor: Triceps, Wrist flexion Reflex: Triceps

C4–C5 Disk: C5 Nerve Root Pain: Neck, tip of shoulder, anterior arm Sensation: Deltoid area Motor: Deltoid, biceps Reflex: Biceps

C7–T1 Dicks: C8 Nerve Root Pain: Neck, medial scapula, medial arm/forearm Sensation: Ring and little finger Motor: Intrinsic muscles of hand Reflex: None

sign. The arm is abducted overhead decreasing the ten sion on th e affected n erve an d th ereby th e severity of th e radicular sym ptom s. The m ajor focus of the exam in ation is directed at fin ding a n eurologic deficit (Table 12.1). Th e m ost likely objective fin din g is a m otor deficit or dim in ish ed deep ten don reflex in th e distribution of th e affected n erve. It is in th is way th at the specific root affected can be identified. It is importan t to isolate each group of m uscles rath er th an test gross stren gth with actions that in volve a com bination of m uscle groups. Sen sory ch an ges are in con sisten tly presen t an d sh ould n ot bare th e brun t of th e physical exam in ation but rath er provide addition al in form ation wh en presen t. O n e m ust keep in m in d th at th e physical exam in ation is n ot always precise as crossover between myotom es an d derm atom es exists. It m ust also be n oted th at radiculopathy an d myelopathy can coexist, an d physical exam ination findings can m irror this.

Diagnostic Studies It m ust be emph asized th at th e core of th e in form ation obtain ed sh ould be from th e h istory an d physical exam ination, and diagnostic studies should be used to con firm the clin ical impression. Many of th ese studies are overly sen sitive and relatively nonspecific and th erefore should not be used for screen in g purposes. Wh en in terpreting th e in form ation gain ed from th ese studies, th e clin ical picture needs to be correlated with the fin din gs in the study, an d the studies should n ever be interpreted in isolation.

Plain Radiographs As discussed previously, the typical plain film s of the cervical spine should include AP, lateral, oblique, and odontoid views. Plain film s provide importan t in form ation regarding degenerative changes an d can suggest th e specific level of the cervical spine involved. The generally accepted radiograph ic sign s of cervical disk disease in clude loss of h eigh t of th e disk space, osteophyte form ation , secon dary en croach m en t of th e in tervertebral foram in a, an d osteoarth ritic ch an ges in th e apophyseal join ts. Align m en t an d listh esis (slippin g) of one vertebral body on another sh ould be exam in ed as well. It m ust be stressed th at th e iden tification of “som e path ology’’ on plain cervical film s does n ot n ecessarily in dicate th e cause of th e patien t’s sym ptom s as several studies have sh own th at a large percentage of asymptom atic individuals have radiographic evidence of degenerative ch anges on x-ray. MRI MRI is currently the study of choice when evaluating root compression (or cord compression in the case of myelopathy). MRI is excellent at clearly visualizing the cord and roots an d sten osis or compression of both . It is best at iden tifying soft tissues, so herniated intervertebral disks (soft disks) (Fig. 12.19) causin g root com pression are better visualized th an osteophytes (hard disks) causing compression, but both can be appreciated. Foram in al sten osis is also well visualized. Additionally, MRI is safe (does not use ionizing radiation an d rarely uses con trast agen ts) an d is curren tly becom in g ch eaper, alth ough it is still a m uch m ore expen sive test than CT. The only caution is the prevalence of fin din gs in asym ptom atic patien ts is very h igh (19%), an d results sh ould th erefore be strictly correlated with th e h istory an d physical exam in ation . CT Th e use of CT scan n in g in th e spin e, as with any oth er place in the body, visualizes the bony anatomy m uch better than the soft tissues an d is thus lim ited in detecting soft-tissue path ology causin g im pin gem en t. However, CT does visualize bony causes of impingem ent better th an MRI. In general, it is used for th ose patien ts wh o can n ot un dergo MRI or in th ose in wh ich th e MRI is equivocal. Th e addition of myelography (in jection of dye in to th e spin al can al prior to im aging) m ay be necessary if surgical treatm ent is considered. In gen eral, CT with or with out myelography is used as a backup test to MRI in the evaluation of a radiculopathy. Electromyography Electromyography (EMG) is an electrical test th at con firm s the interaction of nerve to m uscle. It is perform ed by placing needles into specific m uscles to determ ine if there is an intact nerve supply to that m uscle. EMG is particularly useful in localizing a specific abnorm al nerve root. However, it


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tim in g of th e study. If on ly th e sen sory portion of th e n erve is affected, th e EMG will be n egative as EMG tests m otor in n ervation . As previously m en tion ed, th e study will also read as n egative if perform ed too early. Th erefore, a n egative study sh ould be repeated 3 weeks later if symptom s still persist and a diagn osis has not been m ade. It m ust be n oted th at EMG is n ot part of th e routin e evaluation of th e cervical spin e an d sh ould be used to con firm on e’s clinical suspicion or to rule out other pathologies such as periph eral or compressive n europath ies.

A

Natural History Gen erally speakin g, th e n atural h istory of cervical radiculopathy is favorable with the m ajority resolving with nonoperative treatm en t. Lees an d Turn er studied th e n atural h istory in 51 patien ts an d sh owed th at 45% h ad on ly 1 episode with resolution , while 25% reported persistent sym ptom s. The rem ain der had m ild symptom s, and no patient progressed to myelopathic symptom s. Therefore, nonoperative m an agem en t is th e in itial treatm en t of ch oice. Th e question rem ain s as to wh eth er m eth ods of n on operative treatm ent actually improve the course of th e disease or wh eth er n on operative treatm en t provides symptom atic relief on ly. Th ere is lim ited in form ation comparin g n on operative treatm en ts, an d it rem ain s surgeon preferen ce as to wh ich m eth od to use. Th e differen t m eth ods of treatm en t are discussed in the individual sections on th e pathologies causing radiculopathy (i.e., herniated disk, cervical spon dylosis) as well as in the treatm ent algorithm for cervical path ology.

Cervical Myelopathy Cervical Myelopathy is defined as compression of the spin al cord, wh ich is usually due to degenerative changes. Th e compression occurs on th e cord itself, wh ich differen tiates it from radiculopathy, where compression is on the individual root.

B Figure 12.19 Disk herniation. Midsagittal (A) and axial (B) T2-

weighted MRI depicting left paracentral herniation extending into the neuroforamen. (Reproduced with permission from Frymoyer JW, Wiesel SW, An HS, et al. The Adult and Pediatric Spine, 3rd ed. Philadelphia: Lippincott Williams & Wilkins, 2003.)

takes at least 21 days from th e tim e of n erve impin gem en t for an EMG to sh ow up as abnorm al. Before that period of tim e, the EMG m ay be un rem arkable as th e nerve has n ot experien ced en ough pressure to sh ow sign s of den ervation . Th e accuracy of EMG is aroun d 80% to 90% in establishing th e diagnosis of cervical radiculopathy. Reasons for false n egatives in clude sen sory root in volvem en t on ly an d

History Myelopathy typically presen ts in those over the age of 50 with m ales predom in atin g over fem ales. Th e on set is gen erally in sidious with sym ptom s worsen in g over tim e. Com m on presentin g symptom s in clude n um bness and paresth esias in th e h an ds, clum sin ess of th e fin gers, weakn ess (greatest in the lower extrem ities), an d gait/ balance disturban ces. Abn orm alities of m icturition can occur an d indicate m ore severe or progressed cord in volvem en t. Sensory abn orm alities are also com m on and m ay show a patchy distribution . Spin oth alam ic tract (pain an d tem perature) deficits can be seen through out an d are classically described as bein g in a stockin g or glove distribution . Posterior colum n deficits (vibration an d proprioception ) also com m on ly occur in th e h an ds an d feet. Th e patien t typically com plain s of globally dim in ish ed appreciation of touch or

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sen sation. It m ust be noted th at a sign ificant am oun t of patien ts will presen t with radiculopath ic sym ptom s in addition to myelopath ic sym ptom s th us cloudin g th e presen tation .

Physical Examination Th e myelopath ic physical exam in ation will gen erally h ave nonspecific findin gs in addition to fin din gs specific to cord compression. One non specific but important findin g is lim ited n eck exten sion on exam in ation secon dary to pain from th e n arrowed can al. Especially im portan t with myelopathy is a full neurologic exam in ation with particular atten tion paid to weakn ess, m uscle atrophy, an d clum sin ess in both th e upper an d lower extrem ities. Th ere are various specific m aneuvers described for han d/ finger clum sin ess in cludin g rapidly open in g an d closin g th e h an ds, wh ich is often slowed. In th e lower extrem ities, th e usual fin din gs are spasticity an d weakn ess, in addition to atrophy (pyram idal tract sign s). O n th e reflex exam in ation , hyperreflexia, clon us, an d a positive Babin ski’s sign are often positive in th e lower extrem ities, wh ile hyperreflexia an d a positive Hoffm an ’s sign m ay be observed in th e upper extrem ities. Sen sory exam in ation sh ould be docum en ted but is m uch less sen sitive. Usually there is no gross sensory dysfunction but rather a patchy decrease in ligh t touch an d pin prick. Th e sen sory exam in ation does n ot m ake th e diagn osis but can support the diagn osis. Fin ally, it is importan t to assess th e patien t’s gait. Th e classic myelopathic gait is described as a wide-based gait an d furth er testin g m ay sh ow difficulty with toe walkin g, h eel walkin g, an d/or h eel–toe gait. Addition ally, th e Rom berg’s test can be positive, dem on stratin g a disturban ce in balan ce secon dary to dysfun ction in th e posterior colum n. Diagnostic Studies Again , it m ust be emphasized that th e core of the inform ation obtain ed sh ould be from th e h istory an d physical exam in ation , an d diagn ostic studies sh ould be used to con firm th e clin ical impression . Many of th ese studies are overly sen sitive an d relatively n on specific an d th erefore should not be used for screen ing purposes as they can iden tify path ology in asymptom atic in dividuals for wh ich no treatm ent is necessary. Th erefore, when in terpretin g th e in form ation gain ed from th ese studies, th e clin ical picture needs to be correlated with the fin din gs in the study, an d the studies should n ever be interpreted in isolation. Plain Films Radiograph s of th e cervical spin e in myelopath ic patien ts typically sh ow ch an ges con sisten t with advan ced degen erative disease. Fin din gs in clude disk-space n arrowin g, en d plate sclerosis, facet join t arth rosis, osteophytosis with spin al canal narrowing/ foram inal n arrowing, an d in stability. Con gen ital cervical sten osis, defin ed as a can al less th an

Figure 12.20 Multilevel disk herniation causing cord compres-

sion with myelopathy. Note multiple disk herniations (arrows). (Reprinted with permission from Ross JS. MRI of the Spine, 2nd ed. Philadelphia: Lippincott Williams & Wilkins, 2000.)

13 m m in diam eter, is frequently seen and predisposes th e patien t to myelopathy.

MRI In a patien t with a physical exam in ation con sisten t with myelopathy, an MRI is th e n ext step after plain film s. Th e MRI findings can be very impressive as it im ages the cord/ soft tissue extrem ely well, thereby allowing one to visualize cord impin gem en t closely (Fig. 12.20). The typical findings are cord compression at m ultiple levels, disk herniation , facet hypertrophy, bucklin g/ hypertrophy of th e ligam en tum flavum , and soft-tissue changes. It m ust be stressed again to correlate findings with th e physical exam ination as MRI is often positive in asymptom atic in dividuals. Natural History Th e n atural h istory for cervical myelopathy is n ot as favorable as for radiculopathy, but it is not an absolute indication for surgery. Patien ts typically experien ce plateau periods followed by exacerbation s of th e disease. It differs from radiculopathy in the sense that generally speaking it is progressive. Th e rapidity of progression varies from patien t to patien t with m ost even tually requirin g surgery. Management Th ere rem ain s a lim ited role for n on operative treatm en t in itially, but on ce further deterioration is observed, surgery is clearly indicated. Conservative m anagem ent involves im m obilization and rest with a cervical orthosis. To our knowledge, there are no good clinical trials indicating that


con servative treatm ent alters disease progression, although it offers an option for those who are not good operative candidates and those who have m inor symptom s. The absolute indications for surgery are not clearly defin ed an d vary from surgeon to surgeon . However, m ost would agree that n eurologic deterioration m arks a need for surgical interven tion . Th e goals of surgery are decompression of th e cord with prevention of further cord compression and vascular comprom ise.

Cervical Spine Clinical Conditions Many conditions m ay present as neck pain, radiculopathy, myelopathy, or any com bin ation in any particular in dividual. Th ose th at are m ost com m on will be presen ted in detail below.

Neck Sprain (or Strain) and Neck Ache Neck sprain , wh ile a m isn om er, describes a clin ical con dition in volvin g a n on radiatin g discom fort or pain about the n eck area associated with a concom itant loss of neck m otion (stiffness). Alth ough the clin ical syndrom e m ay presen t as a h eadach e, m ost often th e pain is located in the m iddle to lower part of the back of the n eck with various pattern s of referred pain that m ay be present in addition to or instead of the typical pattern. A history of injury is rarely obtained, but the pain m ay start after a night’s rest or simply on turnin g the h ead. Th e in fam ous traum atic form of neck sprain , the whiplash injury, is a cervical acceleration –deceleration in jury from an MVA in wh ich a car is rear en ded, resultin g in cervical hyperflexion followed by hyperexten sion causing a neck sprain . Th is con dition is som ewhat different from the m ore com m on atraum atic (or m inim ally traum atic) form s, and will not be discussed furth er, but th e sam e structures are in volved resultin g in sim ilar pain pattern s. Th e n atural h istory of traum atic neck strain, however, m ay be differen t for a variety of reason s, in cludin g litigation , wh ich is beyon d th e scope of this ch apter. Th ere is debate about th e actual source(s) of th e pain with a cervical sprain , but it is com m on ly believed to be th e ligam ents about the cervical spine and the facet joints, as well as th e surroun din g m usculature. Th e ligam en ts con tain n erve en din gs resultin g in pain sen sation , wh ile th e m usculature surrounding the dam aged area tends to contract to essentially protect or splint the involved area resulting in a myofascial pain syndrom e. Additionally, axial pain m ay be produced by sm all ann ular tears within the disk with out actual disk h ern iation . Th e pain m ost often associated with a n eck sprain is a dull ach in g pain , wh ich is exacerbated by n eck m otion an d abated by rest or im m obilization. The pain m ay be referred to oth er m esen chym al structures derived from a sim ilar sclerotom e during em bryogenesis. Com m on referred pain pattern s in clude th e scapular area, th e posterior sh oulder, the occipital area, or the anterior chest wall (cervical angina

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pectoris). Th ose referred pain pattern s do n ot con n ote a true radicular pattern an d are n ot usually m ech an ical in origin . Physical exam in ation of patien ts with n eck ach e usually reveals n oth in g m ore th an a locally ten der area(s) just lateral to th e spin e in th e area of th e paraspin al m usculature with or with out loss of m otion secon dary to pain . Th e in ten sity of th e pain is variable, an d th e loss of cervical m otion correlates directly with th e pain in ten sity. Th e presen ce of true spasm , defin ed as a con tin uous m uscle con traction , is rare except in severe cases wh en th e h ead m ay be tilted to on e side (torticollis). Th ere are n o exam in ation fin din gs suggestive of radiculopathy or myelopathy. Radiograph s with a n eck ach e or sprain are usually n orm al an d, th erefore, are n ot warran ted on th e in itial visit wh en th e workin g diagn osis is neck ach e. If the pain contin ues for m ore th an 2 weeks or th e patien t develops oth er physical fin din gs, radiograph s sh ould be taken to rule out m ore serious causes for th e clin ical picture, such as in stability or n eoplasm . Th e progn osis for patien ts with n eck ach e is excellen t— the natural history is one of complete resolution of the symptom s over several weeks. The m ainstay of therapy in cludes rest and im m obilization, possibly in a soft cervical orth osis for com fort. NSAIDs an d m uscle relaxan ts will aid in com fort as well; h owever, n on e of th ese treatm en ts seem to alter th e duration of th e n atural h istory of th is disorder.

Acute Herniated Disk A h ern iated disk is defin ed as th e protrusion of th e n ucleus pulposus th rough th e fibers of th e an n ulus fibrosis. Th is gen erally occurs aroun d th e fourth decade wh en th e n ucleus is still gelatin ous. O lder patien ts will rarely h ave an acute disk herniation secondary to th e loss of water conten t in th e n ucleus pulposus, wh ich leads to an in ability of th e n ucleus pulposus to protrude th rough th e an n ulus. Most herniations occur posterolaterally, alth ough central and intraforam in al protrusion can occur as well. The h igher incidence of posterolateral protrusion is thought to be secon dary to th e relative weakn ess of th e PLL just lateral to th e m idline with subsequent protrusion through perforations in the region. The m ost com m on areas of cervical disk hern iation are C5 –C6 an d C6 –C7, wh ereas C7 –T1 an d C3 –C4 occur in frequen tly, an d C2 –C3 h ern iation is extrem ely rare. Th e disk h ern iation in th e cervical spin e gen erally results in a radiculopathy secon dary to root impin gem ent, but un like th e lum bar spin e, fin din gs of m yelopathy m ay be presen t as well. Th e h ern iation will cause pressure on th e local nerve root in addition to pressure on the cord in the region , with th e am oun t of cord pressure depen din g on th e laterality of th e h ern iation . More cen tral h ern iation s are m ore likely to result in significant cord compression. Cervical disk herniation usually affects the root num bered lowest for the given disk level as that is the nerve that even tually exits through th e foram en at that level. For example, a C3 –C4 disk affects the C4 root, C4 –C5 affects th e C5 root,

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C5 –C6 affects th e C6 root, C6 –C7 affects th e C7 root, an d C7 –T1 affects th e C8 root. Herniated disks result in a wide array of symptom atology from asym ptom atic to debilitatin g pain with n eurologic symptom s. Th e presen ce of symptom s depen ds on the spinal reserve capacity or size of th e canal (am ount of space available for th e n erve/ cord to be displaced prior to impin gem en t), presen ce of in flam m ation , size of th e h erniation, an d concom itant disease such as associated osteophyte form ation . Gen erally, th e patien t’s m ajor com plain t is arm pain , with m in or complain ts of n eck pain . Th e pain is often perceived as startin g in th e n eck area an d radiatin g from th is poin t down th e sh oulder to th e arm , forearm , an d often th e h an d in a derm atom al distribution . Th e on set is usually gradual, alth ough sudden on set can occur often with a snapping sen sation . As m entioned earlier, th e severity of th e arm pain varies from in capacitatin g to a dull ach e. Th e pain is gen erally en ough to awaken th e patien t at n igh t. The physical exam in ation varies dependin g on th e root in volved as well as th e am oun t, if any, of cord impin gem en t. Non specific physical exam in ation fin din gs in clude lim ited ran ge of m otion , pain with ran ge of m otion , positive Spurlin g’s sign , pain with valsalva m an euver, an d pain with spine exten sion secon dary to narrowing of th e intervertebral foram en . Th e m ost importan t or h elpful fin din g on exam in ation is a positive n eurologic fin din g as th is will allow on e to pinpoin t th e area of impin gem en t. To be significant, the n eurologic exam ination m ust sh ow objective signs of reflex dim in ution (in com parison with the opposite side), m otor weakness, an d/ or atrophy in a m yotom al region . Subjective sen sory fin din gs are difficult to in terpret, an d sen sory ch an ges alon e are n ot en ough to m ake a firm diagn osis. Addition ally, fin din gs of clon us, hyperreflexia, Babinski’s sign, Hoffm an ’s sign , and/ or other myelopath ic signs are significan t as they are m anifestations of cord im pin gem en t. However, th ey are less h elpful in pinpoin tin g the exact area of involvem ent. After the provisional diagnosis of a herniated disk is m ade by th e h istory an d physical exam in ation , radiologic studies are don e to con firm th e diagn osis an d to evaluate th e exten t an d level(s) of in volvem en t. Plain film s are obtain ed first, alth ough th ey are often of little diagn ostic utility. Th eir value largely lies in excludin g oth er causes of n eck an d arm pain . Th e m ost useful in form ation will be obtain ed from MRI, but MRI sh ould on ly be used as a con firm atory study as aroun d 10% of asymptom atic in dividuals un der 40 years of age will h ave eviden ce of a hern iated disk on MRI. MRI is excellent at visualizing th e disks an d th e cord an d th us is excellen t at con firm in g h erniated disks an d the am ount of impingem ent presen t. As discussed previously, positive fin din gs on MRI sh ould be correlated with the physical exam ination and the patien t sh ould be treated according to the physical findin gs rather than the findings on MRI. The m ost helpful MR im ages are on th e sagittal an d axial views sh owin g protrusion of th e disk in to th e can al with im pin gem en t on th e cord an d/ or

n erve roots (Fig. 12.19). Oth er studies such as EMG/ NCS can be don e to sh ow eviden ce of n erve root in volvem en t, but th ey are less sen sitive an d specific th an MRI an d as such are used less often. Th e treatm en t for m ost patien ts with a h ern iated disk is n on operative, and th e m ajority of patients respond over a period of m on th s. Th e efficacy of the nonoperative approach depen ds h eavily on th e doctor–patien t relation sh ip with open com m un ication for th e patien t to un derstan d th e n atural h istory of th e disease. If a patien t is well in form ed, in sigh tful, and willing to follow in structions, the chances for a successful nonoperative outcom e are greatly improved. Th e corn erston e to m an agem en t of a cervical h ern iated disk is rest an d im m obilization , possibly in a cervical orth osis for pain relief. Th e use of a cervical orth osis greatly increases the likelih ood th at the patient will rest. Patien ts sh ould m arkedly decrease their physical activity for at least 2 weeks while the sym ptom s are m ost acute. After the acute pain begin s to abate, patien ts sh ould gradually in crease th eir activity. Most patien ts will be able to return to work, or at least to ligh t activities, in a m on th . Ph arm aceutical th erapy is an im portan t adjun ct to rest and im m obilization. Anti-inflam m atory m edication, analgesic m edication s, an d m uscle relaxan ts h ave been used h istorically in the acute setting. Because it is believed that the radicular pain is in part in flam m atory, th e use of NSAIDs seem s appropriate. Much m ore controversial is the role of n arcotics and m uscle relaxan ts. Many believe th at n arcotics sh ould on ly be used if th e pain is severe and the patien t h as failed a trial of an ti-in flam m atory m edication s. Oth ers are m uch m ore liberal with narcotic prescriptions. We believe th at th ere is a lim ited role for n arcotics an d on ly in th e acute setting only. They sh ould be used sparingly, and it sh ould be m ade clear th at th ey are not for extended treatm ent. Long-term use should be prohibited secon dary to the addictive properties of the m edications, as there are m any patien ts wh o suffer from th is if con tin ued use is allowed. Rarely a patien t m ay n eed to be adm itted to th e h ospital for a short period of tim e for pain relief. Surgical treatm en t is reserved for patien ts with un rem itting radicular symptom s after an adequate period of conservative th erapy. Wh at constitutes an adequate period of con servative th erapy is con troversial. Th e presen ce of an isolated neurologic finding, such as an absent bicep reflex, is n ot an indication for surgery. Th e goal of surgery is to relieve pain . Return of an isolated neurologic deficit is unpredictable. The results of surgery for pain relief are quite good (over 90%) wh en th e h istory, physical exam ination, and diagnostic studies are confirm atory. Surgery gen erally in volves an terior cervical discectomy an d fusion (ACDF), although lam inoforam inotomy with or without discectomy m ay be a reason able altern ative. Disk replacem ent is a newer technique that has shown som e prom ise, alth ough th e long-term results are not known. Proponents for disk replacem en t over fusion site that ran ge of m otion


is m aintained, possibly dim inish ing the am ount of segm en tal disease at the levels above and below the fusion site.

Cervical Spondylosis Once com m on ly referred to as “cervical degenerative disk disease,’’ cervical spon dylosis is a ch ron ic process defin ed as the developm en t of osteophytes an d other stigm ata of degen erative arth ritis as a con sequen ce of age-related disk disease. Th is process m ay produce a wide array of sym ptom s from n eck pain to symptom s of a radiculopathy an d/or myelopathy. Th e process begin s with disk degen eration from agerelated ch an ges resultin g in a ch an ge in th e proteoglycan an d collagen conten t of the disk as well as loss of water con tent. Ultim ately, these changes lead to desiccation of the n ucleus pulposus, loss of annular elasticity, an d narrowin g of th e disk space with or with out disk protrusion or rupture. Th e ch an ges with in th e disk an d th e loss of disk height disrupt the biom ech anics in th e vertebral colum n , resultin g in progressive degen eration an d m otion between segm en ts. Increased m otion between segm ents results in overridin g facets, facet hypertrophy, in flam m ation of th e syn ovium , osteophyte form ation, hypertrophy of th e ligam en tum flavum and/ or PLL, and even m icrofractures. Depen din g on th e location of th ese ch an ges with in th e spin e, a variety of clin ical syndrom es can occur including spon dylosis, ankylosis, central or foram inal spinal stenosis, radiculopathy, myelopathy, or spinal segm ental instability. Th e typical patien t with spon dylosis alon e (i.e., with out radiculopathy an d/ or myelopathy) is over th e age of 40 with a prim ary complain t of n eck pain . Not in frequen tly, however, these patien ts will h ave little neck pain and will presen t with referred pain pattern s: occipital h eadach es or as pain in the sh oulder, suboccipital, interscapular areas, an d/or the anterior ch est wall. In patients with predom inantly referred pain, a previous history of neck pain is usually obtain ed. Th ese patien ts h ave n on specific physical exam in ation fin din gs. Th e patien t with spon dylosis an d radiculopathy an d/ or myelopathy will often h ave little n eck pain but rath er presen t m ain ly with radicular an d/ or m yelopath ic sym ptom s. Radiculopathy results from irritation of th e n erve root from a bony protuberan ce (osteophytes, facet join t hypertrophy) or less com m on ly soft disk h ern iation as th e nerve root is exiting the canal. This is com m only referred to as foram inal sten osis. Myelopathy can result from a sim ilar process; h owever, th e cord is impin ged from cen tral rath er than foram inal stenosis. Central sten osis occurs from disk bulgin g (less com m on ), un covertebral hypertrophy, vertebral en d plate osteophytes, an d/ or ligam en tum flavum hypertrophy. Posterior osteophytes causin g cord im pin gem en t are com m only referred to as “hard disks’’ that delineates th em from in tervertebral disk h ern iation , “soft disks.’’ Com m on ly, radiculopathy and myelopathy will coexist in these patients, referred to as myeloradiculopathy.

467

Myelopathy occurs in less than 5% of patients with spon dylosis, but it is th e m ost serious sequelae and the m ost difficult to treat effectively. Th e symptom s are gen erally gradual, an d patien ts typically n otice loss of dexterity in th eir h an ds an d m ore difficulty with gait. Th ey m ay exh ibit th e typical stooped, wide-based, an d som ewh at jerky gait of ch ron ic myelopathy. Physical exam in ation m ay dem on strate hyperreflexia, Hoffm an ’s sign , Babin ski’s sign , clonus, and/ or other findings previously discussed in the myelopathy section. Radiograph s of patien ts with cervical spon dylosis will sh ow varying degrees of changes depending on the severity of th e disease in cludin g disk space n arrowin g, osteophytosis, foram in al n arrowin g, facet hypertrophy, an d instability (Fig. 12.21). In patien ts without radicular an d/ or myelopath ic fin din gs, furth er diagn ostic testin g is un n ecessary. In patien ts with th ese fin din gs, h owever, on e sh ould pursue furth er im agin g preferably with an MRI. Treatm ent of cervical spondylosis varies, again, depen din g on th e severity of th e disease. Spon dylosis alon e is treated with n on operative m easures. Th e m ain stay of treatm en t for th e acute pain superimposed on th e ch ron ic problem is rest an d im m obilization in addition to an tiin flam m atory m edication s, wh ich often will n eed to be taken lon g term . Addition ally, trigger poin t in jection s can be perform ed an d m any tim es will provide substan tial relief. Trigger poin t in jection s con tain a local an esth etic com bin ed with a corticosteroid adm in istered in th e poin ts or areas of m axim al ten dern ess. Patien ts m ay also begin a program of physical th erapy emphasizin g isom etric exercises aim ed at ton in g debilitated m usculature in th e cervical region with th e ben efit of addin g m ore stabilization to th e cervical region. Fin ally, patients should be counseled regardin g sleepin g position , autom obile drivin g, an d work. It sh ould be noted that axial n eck pain alon e does n ot respon d well to surgical stabilization , an d th us surgery is rarely employed. Patien ts with radiculopathy sh ould follow th e sam e con servative m an agem en t pathway with the addition of selective n erve root blocks an d epidural steroid in jection s. If conservative m an agem ent fails, surgical in terven tion can then be employed with success rates of over 90%. The type of surgery perform ed depen ds on th e location of the pathology with surgical options including posterior lam in oforam in otomy for isolated purely foram in al sten osis but m ore com m on ly ACDF as isolated disease is the exception rath er th an th e n orm . Spon dylosis with myelopathy is a surgical disease but is n ot an absolute in dication for surgical decompression . Con servative th erapy as discussed earlier offers th e myelopath ic patien t, wh o is n ot a good operative risk, a viable option . Depen din g on th e aggressiven ess of th e surgeon , the in dications for operative treatm ent vary slightly as there is a lack of absolute defin itive clin ical data. If th e disease progresses despite a trial of con servative th erapy, surgery is clearly in dicated to preven t furth er progression . Th e

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A

B

C Figure 12.21 Spondylosis with myelopathy. A 78-year-old woman presenting with myelopathy including myelopathic hand, broad-based gait, and positive Hoffman’s sign on left. (A) AP radiograph demonstrates severe uncovertebral joint narrowing (arrows) and sclerosis characteristic of advanced osteolysis. (B) Lateral radiograph demonstrates anterolisthesis of C4 on C5 (open arrow) with severe disk space narrowing of C5–C6, C6–C7, and C7–T1 (closed arrows). Note also the anterior osteophytes (small arrows) and concomitant loss of the normal cervical lordosis. (C) Transaxial CT scan at the C5– C6 disk level demonstrates a large posterior hard disk (arrow) protruding into the spinal canal with associated uncovertebral joint osteophytes. (Reproduced with permission from Frymoyer JW, Wiesel SW, An HS, et al. The Adult and Pediatric Spine, 3rd ed. Philadelphia: Lippincott Williams & Wilkins, 2003.)

goals of surgery in th e myelopath ic patien t are decompression of th e spinal cord an d preven tion of furth er neurologic deterioration . ACDF is used in th e m ajority of cases, alth ough with m ultilevel disease, lam in oplasty m ay be in dicated.

Rheumatoid Arthritis Rh eum atoid arth ritis (RA) is an autoim m un e in flam m atory arth ropathy affectin g aroun d 2% of th e population with cervical spine in volvem en t becom ing symptom atic in aroun d 60% of rh eum atoid patien ts an d radiograph ic in -

volvem en t occurring as high as 85% of patients. As with oth er areas in th e body, ch ron ic syn ovial in flam m ation even tually leads to destruction of th e ligam en ts, join ts, an d bon e causin g in stability an d pain in th e cervical region . If left untreated, severe pain, neurologic deterioration , and death can occur. With th e sign ifican t im provem en t of th e m edical m anagem ent of RA through disease m odifying anti-rheum atoid drugs, the n um ber and severity of cases sh ould con tinue to decline. Cervical spin e in volvem en t secon dary to th e erosive inflam m atory chan ges of RA is divided into th ree m ain


469

Figure 12.22 Patterns of cervical spine instability secondary to rheumatoid arthritis. (A,B) Atlantoaxial instability. (C) Cranial settling (basilar invagination). (D) Subaxial instability. (Reproduced with permission from Chapman MW. Chapman’s Orthopaedic Surgery, 3rd ed. Philadelphia, Lippincott Williams & Wilkins, 2000.)

A

B

categories: (1) atlantoaxial instability, (2) basilar in vagination, and (3) subaxial instability (Fig. 12.22). Atlantoaxial instability is the m ost com m on form of instability accounting for approxim ately 70% of the cases. In flam m ation and pan n us form ation lead to weaken in g of th e ligam en tous structures about C1 and C2, eventually resultin g in an terior subluxation of C1 on C2. Subluxation results in cord im pin gem en t as th e SAC decreases. Basilar in vagin ation refers to th e ceph alad m igration of th e odon toid secon dary to in volvem ent of the atlan toaxial and atlanto-occipital joints, resultin g in impaction of th e odon toid on th e brain stem with severity depen din g on th e am oun t of m igration . Th is is the least com m on yet m ost feared complication of RA of the cervical spine as severe neurologic deficits can occur, an d death from compression on the respiratory center at the brainstem is possible. Subaxial instability occurs in approxim ately 25% of th e cases, resultin g in decreased SAC via the sam e m echanism as in atlantoaxial instability. Sym ptom atic patien ts with cervical spin e in volvem en t typically complain of neck pain in th e m iddle, posterior neck, and occipital area with varying complaints of weakness about the neck itself and/ or in the extrem ities. Physical exam in ation sh ould start with a careful n eurologic exam ination, which often can be difficult with the associated ch anges in the appendicular skeleton. Range of m otion of the neck is often decreased an d crepitus or a feeling of in stability m ay be elicited. Plain radiograph s are th e first step after th e physical exam in ation with AP, lateral, odontoid, and lateral flexion/ exten sion views obtain ed. Certain radiograph ic param eters are critical in evaluating the rheum atoid cervical spine. On the lateral view, these include the anterior atlan todents in terval (aADI), th e posterior atlan toden tal in terval (pADI), odon toid m igration in relation to McGregor’s lin e, an d th e spinolam inar line (Fig. 12.4). An aADI 3 m m or greater is significant for atlantoaxial in stability, while a pADI less than 14 m m signifies a decreased SAC with an indication for surgical fixation . Basilar invagination is defined as m igration of th e odon toid tip m ore th an 4.5-m m ceph alad to McGregor’s line (line from hard palate to caudal surface of the basiocciput). Subaxial instability appears as a stepladder appearan ce of th e spin olam in ar lin e kn own as “stepladder’’vertebrae. Flexion / exten sion views are obtain ed to an alyze the extent of atlantoaxial instability as the patient can exh ibit an in creased aADI an d a decreased pADI on th e flexion view in comparison to th e extension view, as well as

C

D

subaxial in stability h igh lighting the stepladder appearance on th e flexion view, wh ich m ay n ot be presen t on n eutral or exten sion film s. Addition al radiograph ic fin din gs in clude osteopen ia, facet erosion , an d disk space n arrowin g. CT is very h elpful followin g plain film s to m ore accurately determ in e th e m easurem en ts m en tion ed earlier as well as for surgical plan n in g. Th e addition of MRI evaluates th e am oun t of cord compression an d visualizes th e am oun t of pan n us form ation at the odontoid as well as other soft-tissue inflam m ation, resulting in canal space narrowing that cann ot be appreciated on plain film s or CT scan (Fig. 12.23). Th e m ajority of th ese patien ts, despite dram atic disease pattern s, can be successfully m an aged n on operatively. Alth ough th e n atural h istory of RA predicts a h igh in ciden ce of cervical in volvem en t with progression (th e spin e does n ot stabilize itself over tim e), few patien ts die from m edullary compression, and only approxim ately 10% of patien ts with atlan toaxial disease exh ibit n eurologic compression. Th e m ainstay of nonoperative m anagem ent is a cervical orth osis alon g with patien t education an d

Figure 12.23 Rheumatoid arthritis pannus formation at odon-

toid. This is a 55-year-old female with rheumatoid arthritis with atlantoaxial instability with an MRI showing large pannus formation (arrow) at the odontoid.

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com m unication with the rheum atologist to m axim ize m edical th erapy. Fin ally, patien ts sh ould be followed with serial radiographs to evaluate for radiographic progression , which m ay place th e patien t at severe risk for neurologic comprom ise. The surgical indication s for th e treatm en t of RA in th e cervical spine are progressive neurologic deficit, axial neck pain un respon sive to n on operative m an agem en t, an d radiograph ic param eters th at place th e patien t at risk for severe neurologic deterioration. Th e following are radiograph ic param eters th at h ave been sh own th rough studies to place patien ts at risk for sign ifican t deterioration : pADI ≤ 14 m m in patients with atlan toaxial instability, cephalad m igration of th e odon toid ≥ 5 m m above McGregor’s lin e represen tin g sign ifican t basilar in vagin ation , an d sagittal can al diam eter ≤ 14 m m in patien ts with subaxial in stability. Of n ote, as previously addressed, un con trollable axial neck pain with no neurologic symptom s m ay be an in dication for surgery in th e rh eum atoid patien t as th ese patien ts do well followin g surgical stabilization for pain con trol. Th is is in con tradistin ction to n on rh eum atoid patien ts presen ting solely with axial pain. Surgical stabilization generally in volves a posterior spin al fusion of all un stable segm en ts.

Cervical Spine Algorithm Th e task of th e physician , wh en con fron ted with th e cervical spine patient, is to integrate the patien t’s complaints into an accurate diagn osis an d to prescribe appropriate th erapy. Ach ieving this goal depends on the accuracy of the physician’s decision -m aking ability. Although specific inform ation is n ot available for every aspect of n eck pain , th ere is a large body of data to guide us in h an dlin g th ese patien ts. Using this knowledge, wh ich has already been presented, an algorith m for n eck pain h as been design ed. Webster defines an algorith m as “a set of rules for solvin g a particular problem in a fin ite n um ber of steps.’’ It is, in effect, an organ ized pattern of decision -m akin g an d though t processes. In this instance, we presen t an algorith m for approaching the universe of cervical spin e patients. The algorith m can be followed in sequen ce (Fig. 12.24). The prim ary objective for th e physician is to return patien ts to n orm al fun ction as quickly as possible. In th e course of achieving this goal, the physician m ust be concerned with other circum stances, which include m aking efficien t an d precise use of diagn ostic studies, m in im izin g the use of ineffectual surgery, and m akin g therapy available at a reason able cost to society. Th e algorith m follows well-delineated rules, established from th e consensus of a broad segm en t of qualified spin e surgeon s. It allows th e patien t to receive th e m ost h elpful diagn ostic an d th erapeutic m easures at optim al tim es. The algorith m begins with the un iverse of patients who are initially evaluated for n eck pain , with or with out arm pain . Patien ts with m ajor traum a, in cludin g fractures,

are excluded from th is algorithm . After an initial history and physical exam ination —and assum ing th at th e patient’s sym ptom s are origin atin g from the cervical spin e—the first m ajor decision is to rule out the presence of a cervical myelopathy. Th e ch aracter an d severity of myelopathy depen d on th e size, location , an d duration of the lesion. Ven trolateral lesion s en croach on th e n erve roots and lateral aspects of the spin al cord, producin g all of the m anifestations accompanyin g n erve root com pression . Th ese lesion s will th erefore give a m ixed presentation with weakness and loss of ton e in the upper extrem ities as well as pyram idal tract signs and spasticity in the lower extrem ities (these m ay also be seen in th e upper extrem ities as well, such as a positive Hoffm an ’s sign ). Midlin e lesion s in trude on th e cen tral aspect of th e an terior portion of th e spin al cord. Th ey produce n o sign s of n erve root compression . Both lower extrem ities are prim arily involved, and the m ost com m on problem relates initially to gait disturban ce, though clum siness of the han ds often follows. As th e disease progresses, bowel an d bladder con trol m ay be affected. On ce a diagnosis of cervical myelopathy is m ade, surgical in terven tion sh ould be con sidered, alth ough m any will advise a short course of conservative treatm en t. An MRI sh ould be perform ed for con firm ation of the diagnosis, determ in ation of th e n um ber of levels in volved, an d for preoperative plan n in g. Th e tim in g of surgery is a m atter of judgm en t. If n on operative m an agem en t is tried, progression of th e disease sign ifies failure of m anagem ent and warrants surgical intervention. After cervical myelopathy has been ruled out, the rem aining patients, who constitute an overwh elm ing m ajority, sh ould be started on a course of conservative m anagem ent. At th is stage of th e patien t’s care, th e specific diagn osis, wh eth er it be a h ern iated disk, degen erative disk disease, or n eck strain , is n ot im portan t because th e en tire group is treated in the sam e fashion.

Conservative Treatment Th e prim ary m ode of th erapy in both acute an d ch ron ic cervical spine disease is im m obilization. In acute neck injuries, im m obilization allows for healin g of torn and attenuated soft tissues, wh ereas in chronic conditions im m obilization is aim ed at reduction of inflam m ation in the supporting soft tissues an d around th e nerve roots of the cervical spine. Im m obilization is best ach ieved by th e use of a soft collar. It needs to be properly fitted and com fortable on the patien t. In itially, th e collar is worn 24 h ours a day. Th e patient m ust understand that during sleep the neck is totally unprotected from awkward position s an d m ovem en ts, an d therefore collar wear is m ost important. Drug th erapy is th e oth er m ain stay of in itial treatm en t. It is directed at reducin g in flam m ation , especially in th e soft tissues. A variety of anti-inflam m atory m edications are


471

NECK PAIN (BRACHIALGIA)

MYELOPATHY (PROGRESSIVE WEAKNESS ATAXIA, LONG TRACT SIGNS)

YES

MYELOGRAM/ MRI

SURGERY

NO

ANTI-INFLAMMATORY MEDICATIONS. REST, AND COLLAR UP TO 3 WEEKS.

YES

ISOMETRIC EXERCISES

NO

BEDREST, PO STEROIDS, AND/OR TRIGGER-POINT INJECTION

FULL ACTIVITY

YES

NO

BRACHIALGIA

NECK PAIN (INTERSCAPULAR RADIATION)

ADSON’S TEST PLAIN X-RAYS AND/OR MOTION FLIMS

YES

VASCULAR STUDIES AND EMG

YES

APPROPRIATE Rx FOR THORASIC OUTLET SYNDROME

NO

YES

INSTABILITY

YES

PLAIN X-RAYS TO INCLUDE CHEST AND SHOULDER

NO

DEGENERATIVE DISEASE

CHRONIC NECK SPRAIN

YES

APPROPRIATE Rx

NO

YES

YES

BRACE AND PERIODIC REEVALUATION

EMG

ISOMETRIC EXERCISES AND PERIODIC REEVALUATION

MEDICAL EVALUATION AND BONE SCAN YES

NO LIMITED ACTIVITY

APPROPRIATE Rx

NERVE COMPRESSION SYNDROME

YES RADICULOPATHY

NO MYELOGRAM/MRI

FUSION YES PSYCHOLOGICAL EVALUATION

CHRONIC PAIN Rx

NO

SURGERY (NERVE ROOT DECOMPRESSION)

ANTIDEPRESSANTS, EDUCATION, PAIN CLINIC, AND PERIODIC REEVALUATION; STOP NARCOTICS

Figure 12.24 Cervical algorithm.

NERVE DECOMPRESSION

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available, with preference often depen ding on the surgeon’s preferen ce, alth ough patien ts with a h istory of gastric ulcers or severe reflux sh ould probably be on a COX-II in h ibitor or else sh ould take an oth er m edication to coun teract or alleviate th e GI side effects of tradition al NSAIDs. Th at bein g said, we prefer naproxen initially as we h ave h ad good success with this m edication. Th e efficacy of this treatm ent regim en is predicated on th e patien t’s ability to un derstan d th e disease process an d th e role of each th erapeutic m odality. Th e vast m ajority of patien ts will respon d to th is approach in th e first 10 days, but a certain percen tage will n ot h eal rapidly. If th e patient is not improvin g at this juncture, a trigger poin t in jection sh ould be con sidered. A trigger poin t in jection is an in jection com bin in g an an esth etic (lidocain e) with 1 m L of a steroid in to th e areas of m axim al ten derness around the paravertebral m usculature an d trapezii. Th ese areas of m axim al ten dern ess are referred to as “trigger poin ts.’’Th e objective is to decrease th e in flam m ation in a specific anatom ic area, thereby relieving pain. The m ore localized th e trigger poin t, th e m ore effective th erapy will be. Often patien ts exh ibit m arked relief of sym ptom s. The patien t should be treated conservatively for up to 6 weeks at which tim e the m ajority of patients will be better an d sh ould be en couraged to gradually in crease th eir activities. Th e goal is for th e patien t to return to h is/h er norm al lifestyle. An exercise program should be directed at stren gth en in g th e paravertebral m usculature, n ot at in creasing the ran ge of m otion. The pathway along this top portion of the algorith m is reversible. Sh ould regression occur with exacerbation of symptom s, th e physician can resort to m ore stringent conservative m easures. Th ese m easures m ay include addition al bed rest an d stron ger an ti-in flam m atory m edication . Th e m ajority of patien ts with n eck pain will respon d to th erapy an d return to a n orm al life pattern with in 2 m on th s of th e begin n in g of th eir problem . If th e in itial con servative treatm ent regim en fails, symptom atic patien ts are divided in to two groups. Th e first group comprises patien ts wh o h ave n eck pain as a predom in an t com plain t, with or with out interscapular radiation. The second group is m ade up of th ose wh o complain prim arily of arm pain (brach ialgia).

Neck Pain Predominance After 6 weeks of conservative therapy with no symptom atic relief, plain roen tgen ogram s are taken an d carefully exam in ed for abn orm alities. Patien ts th en fall in to a subgroup on the basis of th e plain film findin gs. One group of patients will have objective eviden ce of in stability. In the subaxial cervical spine, instability is identified by horizontal translation of on e vertebra on an oth er of m ore th an 3.5 m m or a kyph otic angulation of m ore than 11 degrees. The m ajority of patien ts with in stability will respon d to furth er n on operative m easures, in cludin g th orough education about

th e problem an d symptom atic bracin g an d m edication s. If th ese m easures fail, surgical fusion m ay be required in som e cases. Another group of patients with predom inan tly neck pain will sh ow eviden ce of degen erative ch an ges on plain film s in cluding loss of disk height, osteophyte form ation, foram inal stenosis, and facet hypertrophy. The difficulty is not in identifying the abnorm alities on the radiographs but rath er in determ in in g th eir sign ifican ce. Degen eration in the cervical spine can be a norm al part of the aging process. In a study of m atch ed pairs of asymptom atic an d sym ptom atic patien ts, it was concluded th at large n um bers of asymptom atic patien ts sh ow roen tgen ograph ic evidence of advanced degen erative disease. The m ost significan t roen tgen ograph ic fin din g relevan t to sym ptom s was found to be narrowing of the intervertebral disk space, particularly between C5 –C6 an d C6 –C7. Th ere was n o differen ce between the two groups as far as ch anges at the apophyseal joints, intervertebral foram ina, or posterior articular processes. Th ese patien ts sh ould be treated symptom atically with anti-inflam m atory m edications, support and trigger point injections as required. In the quiescent stages, they should be placed on isom etric exercises. Fin ally, th ey sh ould be reexam in ed periodically because som e will develop myelopathy an d sh ould th en be treated appropriately. Th e m ajority of patien ts with n eck pain predom in an ce will h ave n orm al roen tgen ogram s. Th e diagn osis for th is group of patien ts is n eck strain . At th is poin t, with n o objective fin din gs, oth er path ologic con dition s m ust be con sidered. Th ese patien ts sh ould be considered for a m ore th orough m edical evaluation with con sideration for early tum ors and infection . A thorough m edical search m ay also reveal problem s m issed in th e early stages of n eck pain evaluation . If a m edical cause for th e sym ptom s is iden tified, th e patien t sh ould be treated appropriately. If th e workup is n egative, th e patien t sh ould h ave a th orough psych osocial evaluation . Th is is predicated on th e belief that the patient’s disability is related not on ly to his/ her path ologic an atom y but also to h is/ h er perception of pain , and his/h er stability in relation to his/ her sociologic environ m en t. Drug h abituation , alcoh olism , depression , an d oth er psych iatric problem s are frequen tly seen in association with neck pain. If the evaluation reveals this type of path ology, proper m easures sh ould be in stituted to overcom e th e disability. Sh ould th e outcom e of th e psych osocial evaluation prove to be n orm al, th e patien t can be con sidered to h ave chronic neck pain. One m ust be aware that other outside factors such as compensation or litigation can influen ce a patien t’s perception of h is subjective pain . Patien ts with ch ron ic n eck pain n eed en couragem en t, patien ce, an d education from th eir physician s. Th ey n eed to be detoxified from narcotics and placed on an exercise regim en. Many will respond to antidepressan t m edication s such as am itriptylin e (Elavil). All of these patien ts need periodic


reevaluation to avoid m issin g any n ew or un derlyin g path ology.

Arm Pain Predominance (Brachialgia) Patients who have pain radiating into their arm m ay be experien cin g th eir symptom s secon dary to m ech an ical pressure and in flam m ation of the involved nerve roots. Th is m echanical pressure m ay arise from a ruptured disk (soft disk) or from a bony protuberan ce (h ard disk) secon dary to degen erative ch an ges. Oth er path ologic causes of arm pain sh ould be carefully con sidered. Extrin sic pressure on the vascular structures or the peripheral nerves are the m ost likely im itators of brachialgia. Pathologic involvem ent in the ch est and shoulder should also be ruled out. A careful physical exam ination should be conducted. If th ere is any question about th ese fin din gs, appropriate roen tgen ogram s an d an EMG sh ould be obtain ed. If any of th ese are positive for periph eral pressure on th e n erves or oth er path ology, th e appropriate th erapy sh ould be adm inistered. If th e patient has a positive neurologic deficit on exam in ation or a positive EMG, an MRI sh ould be obtain ed to evaluate for n erve root impin gem en t. If th e MRI is positive, th at patien t is con sidered a can didate for surgical treatm en t, alth ough con servative th erapy sh ould first be attem pted for a period of 6 weeks. If th e patient has not improved with nonoperative treatm ent after 6 weeks, an d th e symptom s are con sisten t with th e exam in ation and diagnostic studies, surgical decompression sh ould be considered. It h as been repeatedly docum en ted th at for surgery to be effective, un equivocal eviden ce of n erve root com pression m ust be found at surgery. One m ust h ave a strong confirm ation of m ech an ical root compression from th e h istory, neurologic exam in ation , and a con firm ing study (i.e., MRI) before proceeding with surgery. If the patient does not have these, th ere is inadequate clin ical eviden ce of root compression to proceed with surgery, regardless of the radiograph ic fin din gs. For in dividuals wh o h ave m et th ese criteria for surgical decompression , the results will usually be satisfactory: 95% of th em can expect good or excellen t outcom es.

LUMBAR SPINE Low-back pain occurs m uch m ore com m only than neck pain . Th e lifetim e in ciden ce of low-back pain is estim ated to be 65%. Every physician will be eith er person ally affected or profession ally ch allen ged by th is problem .

History A gen eral m edical review, especially in th e older patien t, is imperative. Metabolic, in fectious, and m alignant disorders m ay in itially present to the physician as low-back pain.

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Th e location of th e pain is on e of th e m ost importan t h istorical poin ts. The m ajority of patien ts just h ave back pain with or with out referral in to th e buttocks or posterior thigh. Referred pain is defin ed as pain in structures th at h ave th e sam e m esoderm al origin . Th ese patien ts h ave a localized in jury, an d th e referral of pain does n ot sign ify any compression of th e n eural elem en ts. Th is type of pain is described as dull, deep, an d/ or borin g. An oth er group of patien ts com plain s of pain th at origin ates in th e back and travels below th e kn ee in to the foot. It is described as sh arp an d sh ootin g or lan cin atin g. It m ay be accompan ied by n um bn ess an d tin glin g. Th is pain is term ed “radicular pain ’’or a “radiculopathy.’’Aradiculopathy, as discussed in previous sections, is defined as a m ech an ical com pression of a n erve root wh ere th e pain travels alon g th e an atom ic course of th e n erve. Th e compression can be secondary to soft-tissue or bony impingem ent. The m ost com m on n erve roots affected are L5 an d S1—levels that account for pain traveling below the knee. Finally, one should inquire about changes in bowel or bladder h abits. O ccasion ally, a large m idlin e disk h ern iation m ay com press several roots of th e cauda equin a, resulting in cauda equina syndrom e. Urinary reten tion or in con tin en ce of bowel an d bladder (always bladder) are, alon g with severe pain , th e m ajor symptom s. Cauda equin a is con sidered a surgical em ergen cy as spon tan eous recovery h as n ot been observed.

Physical Examination Th e physical exam in ation is directed at fin din g th e location of th e pain and any associated n eurologic findings. All patien ts with low-back pain can h ave n on specific fin dings that vary in degree, depending on the severity of the con dition . Th ese fin din gs in clude a list to on e side, ten dern ess to palpation an d percussion , an d a decreased range of m otion of th e lum bar spin e an d can be presen t in both radiculopath ic an d referred pain patien ts. Th eir presen ce den otes th at th ere is a problem but does n ot iden tify th e etiology or level of th e problem . Th e n eurologic exam in ation m ay yield objective evidence of n erve root compression. If such evidence is presen t, a th orough n eurologic evaluation of th e lower extrem ities should be conducted, particularly to ch eck the reflexes and m otor fin din gs. Sen sory ch an ges m ay or m ay not be presen t, but because of th e overlap in th e derm atom es of spin al n erves, it is difficult to iden tify specific root in volvem en t. In patien ts with radiculopath ies, th ere are several m an euvers that tighten the sciatic n erve an d in so doing, furth er com press an in flam ed lum bar root again st a h ern iated disk or bony spur. Th ese m an euvers are gen erally term ed “ten sion sign s’’ or a “straigh t leg raisin g test’’ (SLRT). The con ven tion al SLRT is perform ed with th e patien t supin e. Th e exam in er slowly elevates th e leg by th e h eel with th e knee kept straight. This test is positive when the leg pain

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below th e kn ee is reproduced or in ten sified; th e production of back pain or buttock pain does n ot con stitute a positive fin din g. Th e reliability of th e SLRT is age depen den t. In a young patien t, a n egative test m ost probably excludes the possibility of a h ern iated disk. After th e age of 30, h owever, a n egative SLRT n o lon ger reliably excludes th e diagn osis. Fin ally, th e physical exam in ation sh ould evaluate som e specific problem s that can presen t as low-back pain . Th is in cludes a periph eral vascular exam in ation , h ip join t evaluation , an d abdom in al exam in ation . There are certain indication s for radiographic studies, which will be discussed in th e section regarding th e lum bar spin e algorith m , but for th e m ost part, radiograph s are un n ecessary on th e in itial visit. If th e patien t return s an d there has been no ch ange in the pain or worsening, plain film s sh ould be obtain ed to rule out m ore serious causes for low-back pain, in cluding tum or. If the patient is having neurologic symptom s, one can consider an MRI to evaluate for disk herniation. Again, the specific tim in g for obtainin g these studies will be discussed in further detail later.

Lumbar Spine-Clinical Entities Back Strain Pain localized to the back or buttocks region with no radiation furth er down th e leg is typically classified as lower back pain , lower back strain , an d/ or lum bar strain , an d th ey are all describin g th e sam e ph en om en on . Approxim ately 80% of th e population , perh aps up to 95%, will experien ce th is clinical entity at som e point during their lifetim e. The exact source of th e pain is not completely understood in m any cases and is probably a com bination of sources that vary between patien ts, but th e poten tial pain gen erators in clude the paraspinal m usculature, ligam ents, facet joints, sinuvertebral n erve in flam m ation , an d in tervertebral disks. Th e history of pain varies from an acute m echanism where th e patien t sudden ly experien ces a severe pain from liftin g or while bendin g over, to awakenin g from sleep with pain , to a slowly progressive, in sidious on set of back pain . Th e severity of the pain differs as well, with som e patients experien cin g debilitatin g pain to oth ers h avin g m ild pain . Low-back pain can con ven ien tly be divided in to th ree categories: m ild, m oderate, and severe. Th ose placed in the m ild group h ave subjective pain with out objective fin din gs an d sh ould be able to return to custom ary activity in less than a week. The m oderate group is characterized by a lim ited ran ge of m otion an d paravertebral m uscle spasm as well as pain, and these patients sh ould be able to return to activities in less th an 2 weeks. Th e severe group in cludes those patients wh o are tilted forward or to the side. They have trouble am bulating and can take up to 3 weeks to becom e fun ction al again . Physical exam in ation of th ese patien ts usually fin ds m ild paravertebral n on specific ten dern ess, lim ited ran ge of m otion , an d n o n eurologic fin din gs. Because n o fin din gs on plain film s is th e n orm for th ese patien ts, radiograph s

are not initially obtained if th e physician is com fortable with th e diagn osis; h owever, if th e respon se to th e treatm ent does not proceed as expected, film s should be taken to rule out other m ore serious problem s, such as spondylolisthesis or tum or. The authors’ usual recom m endation is that if a patient fails to respond to conservative treatm ent for an acute attack of low-back pain after a period of 2 weeks, a routine lum bosacral spine x-ray series is clinically in dicated. Th e auth ors’ preferred treatm en t for low-back strain is th e fun ction al restorative approach . For an acute strain , NSAIDs an d a brief period of activity m odification or rest is indicated to calm down the in flam m atory, painful phase. Addition ally, patien ts sh ould be educated regardin g proper postural m ech an ics to prom ote a h ealthy lower back. O n ce th e acute pain subsides followin g a sh ort period of activity m odification, patients should begin a controlled physical th erapy program either form ally or, for reliable and m otivated patients, on their own. Th e focus of the physical activity is trun k flexibility an d stren gth en in g exercises. Often, particularly in the obese patien t with weak abdom in al m uscles, a ligh tweigh t lum bosacral corset is useful in helping m obilize those en cum bered by low-back strain .

Herniated Disk A h ern iated disk can be defin ed as th e protrusion of th e n ucleus pulposus th rough th e torn fibers of th e annulus fibrosus. Most disk h ern iation s occur durin g th e th ird an d fourth decades of life while the nucleus pulposus is still gelatin ous. Th e perforation s usually arise th rough a defect just lateral to th e posterior m idlin e wh ere th e PLL is weakest. Th e two m ost com m on levels for disk h ern iation are L4 –L5 and L5 –S1, accoun tin g togeth er for 95% of all lum bar disk h ern iation s. Because disk h erniation s are gen erally posterolateral as discussed earlier, th e h ern iation gen erally affects th e n erve traversing the region rather th an th e exiting nerve root. The spin al cord ends aroun d L1/ L2, so th e nerve roots of the lum bar spine exit th e cord well above th at level where they exit th e can al. Th ey, th erefore, h ave a lon g way to travel before exitin g th rough th e foram en , un like in th e cervical spin e. Th e nerves begin m oving laterally and in feriorly from a proxim al direction rather than exitin g alm ost in a straigh t lateral direction like the cervical spine. For this reason , by th e tim e th e nerve root reaches its exiting level, it is already so far lateral from its descent that a hern iated disk at th e level wh ere th e n erve root exits will n ot disrupt it unless the herniation is the m uch less com m on far lateral type. Th erefore, a h ern iated disk will im pin ge upon th e traversing nerve th at exits at th e n ext level down, rath er than the exiting nerve, which differs from a cervical disk herniation that impinges upon the exiting nerve root. However, because th e n erves in th e lum bar spin e exit below th eir respective vertebra, th e sam e rule applies for the likely nerve impinged, which is the nerve nam ed for th e lowest vertebral


segm en t (i.e., L4 –L5 disk herniation impin ges upon L5). Th is con cept is difficult to un derstan d in itially but is a very important on e to grasp conceptually. Th erefore, disk h ern iation s at L5 –S1 usually comprom ise the first sacral n erve root; L4 –L5 herniations affect L5; L3 –L4 hern iations affect L4; an d so forth. As alluded to earlier, variation s do in fact exist in th at far lateral h ern iations can affect the nerve exitin g at the sam e level as th e disk herniation (i.e., L4 –L5 affecting L4), and oth er likely m ore cen tral hern iations can affect the nerves exiting two levels below th e h ern iation (i.e., L4 –L5 affecting th e S1 root). Th ere are a variety of clin ical presen tation s an d h istories regardin g disk h ern iation s, an d n ot everyon e with a disk h ern iation experien ces pain . A large disk h ern iation in a patient with a capacious canal m ay not experience any symptom s at all as the nerves h ave room to be displaced an d avoid compression. On the other end of th e spectrum , a patien t with a sm all can al m ay experien ce debilitatin g pain from a relatively sm all disk h ern iation as th ere is n ot en ough room to accom m odate th e disk an d th e n erve root. Clin ically, th e patien t’s m ajor complain t is pain . Although th ere m ay be a prior h istory of interm ittent episodes of localized low-back pain , th is is n ot always th e case. Th e pain n ot on ly is presen t in th e back but radiates down th e leg in the distribution of the affected n erve root. It will usually be described as sharp, or lancinating, progressing from the top downward in the involved leg. Its onset m ay be insidious or sudden and associated with a tearing or snappin g sen sation in th e spine. O ccasion ally, wh en sciatica develops, th e back pain m ay resolve because on ce th e an n ulus has ruptured, it m ay no longer be un der ten sion. Fin ally, the sciatic pain m ay vary in inten sity as well; it m ay be so severe th at patients will be unable to am bulate an d will feel their back is “locked.’’Conversely, the pain m ay be lim ited to a dull ach e th at in creases in in ten sity with am bulation . O n physical exam in ation , th ere is usually a decreased ran ge of m otion in flexion , an d patien ts will ten d to drift away from th e in volved side with a ben d th at expan ds th e area of the involved side and h ence put less pressure on the nerve. On am bulation, the patients walk with an an talgic gait, holding the in volved leg flexed so as to put as little weigh t as possible on th e extrem ity. Although neurologic exam ination m ay yield objective eviden ce of n erve root com pression , th ese fin din gs are n ot depen dable because th e in volved n erve is often still fun ctional. In addition, such a deficit m ay have little temporal relevan ce if it is related to a prior attack at a differen t level. To be significant, reflex changes, weakness, atrophy, or sen sory ch an ges m ust con form to th e rest of th e clin ical picture. Th e differen t physical fin din gs th at can be presen t are sum m arized in Table 12.2. Involvem en t of th e first sacral nerve can sh ow calf atrophy, weak plan tar flexion or in ability to repeatedly rise on toes, an d/or dim inished Ach illes reflex in comparison to th e opposite side. Fifth lum bar root in volvem en t can lead to weak great toe exten sion an d

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TABLE 12.2

LUMBAR DISK HERNIATION-CLINICAL FEATURES L3–L4 Disk: L4 Nerve Root ■ Pain Lower back, hip, posterolateral thigh, across patella, anteromedial leg ■ Numbness Anteromedial thigh and knee ■ Weakness Knee extension ■ Atrophy Quadriceps ■ Reflexes Patella reflex diminished L4–5 Disk: L5 Nerve Root ■ Pain SI region, hip, posterolateral thigh, anterolateral leg ■ Numbness Lateral leg, first webspace ■ Weakness Dorsiflexion of great toe and foot ■ Atrophy Minimal anterior calf ■ Reflexes None L5–S1 Disk: S1 Nerve Root ■ Pain SI region, hip, posterolateral thigh/leg ■ Numbness Back of calf; lateral heel, foot, and toe ■ Weakness Plantar flexion of foot and great toe ■ Atrophy Gastrocnemius and soleus ■ Reflexes Ankle jerk diminished

less often weak eversion and/ or dorsiflexion. Compression of th e fourth lum bar root can result in weak kn ee exten sion secon dary to quadriceps involvem ent with or without quadriceps atrophy alon g with a dim in ish ed patellar reflex. Of n ote, it is important to compare both sides, especially wh en evaluatin g reflexes as m any people, especially older individuals, have n atural hyporeflexia. Therefore, a dim inished reflex is generally only significant if it is un ilateral. Nerve root sen sitivity can be elicited by any m an euver th at creates ten sion , wh ich m ost often con sists of th e SLRT. For the test to be positive, it m ust reproduce th e leg pain (below the knee), n ot the back pain, as previously highlighted. Th e diagn osis of a lum bar disk h ern iation is m ade by h istory an d physical exam in ation . Th erefore, plain x-rays or MRI do n ot n eed to be obtain ed on an in itial visit. If th e patien t fails con servative treatm en t, plain film s sh ould be obtain ed to rule out oth er causes of pain such as tum or or infection. MRI can be used to confirm the diagnosis (Fig. 12.25) as well as for surgical plan n in g, but it sh ould n ever be used as a screen in g tool as m any asym ptom atic path ologies that do n ot warrant treatm ent can be dem onstrated on MRI an d skew the exam iner an d the patient as to what is actually causing the symptom s. Further guidan ce, tim in g, and indications for radiologic studies will follow in th e lum bar algorith m section. Th e treatm en t for m ost patien ts with a h ern iated disk is n on operative; eighty percen t of th em will respon d to conservative treatm en t wh en followed over a period of five years. The efficacy of n onoperative treatm ent, however, depen ds upon a h ealthy relation sh ip between a capable

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Figure 12.25 Lumbar herniated disk. Sagittal MRI of a 35-year-

old female complaining of back pain with radiation to right ankle. MRI shows a disk herniation (arrow) at L5–S1.

physician an d a well-in form ed patien t. If a patien t h as in sight in to the rationale for the prescribed treatm en t an d follows instructions, the chances for success are greatly increased. O n e of th e m ost importan t elem en ts in n on operative treatm en t is con trolled physical activity. Patien ts sh ould m arkedly decrease th eir activity in th e acute stages. Th is will occasionally require bed rest and in m ost cases can be accomplish ed at h om e. An acute h ern iation usually takes about 2 weeks of rest before th e pain substan tially eases. Drug th erapy is an oth er importan t part of th e treatm en t, an d th ree categories of ph arm acologic agen ts are com m only used: anti-in flam m atory drugs, analgesics, an d m uscle relaxan ts. In asm uch as th e symptom s of low-back pain an d sciatica result from an in flam m atory reaction as well as a m echanical compression , the auth ors feel that an ti-in flam m atory m edication in th e form of aspirin or NSAIDs taken regularly sh ould be in cluded with rest. We prefer n aproxen 500 m g twice daily, alth ough we h ave h ad success with aspirin or oth er NSAIDs as well. For those with GI in toleran ce, celecoxib or a bufferin g agen t can be used. Analgesic m edication is rarely needed if the patien t truly follows th e nonoperative protocol of resting. Occasionally, narcotics will be n eeded to overcom e the in itial hump, although it sh ould be m ade clear th at narcotics will not be used lon g term an d are n ot th e an swer to th e problem . Rarely, a patien t m ay n eed to be adm itted to th e h ospital for pain con trol with IV narcotics. There is som e question as to whether there actually is a m uscle relaxan t; all drugs th at are design ated as such probably act to som e degree as tran quilizers. If on e is required,

cycloben zaprin e is probably th e m ost frequen tly used an d is well tolerated with side effects of sedation and drowsiness occurrin g less often th an with som e of th e oth er m edications, though they do occur. O ther choices include m eth ocarbam ol, carisoprodol, an d valium , alth ough valium is n ot recom m ended secon dary to its depressan t qualities, wh ich can often add to th e patien t’s psych ological problem s. Eigh ty percen t of th ose wh o follow th e above regim en will m arkedly improve, but th is regim en requires patien ce because frequen tly at least 6 weeks will h ave passed before any additional therapy is indicated. Though results are satisfying in the end, patients need to be well aware of the tim e con strain ts from th e begin n in g to un derstan d th e ration ale and to prevent frustration and depression, which often accom pan ies th is disorder. If th ese con servative m easures fail, patien ts sh ould be con sidered for an in jection such as a selective nerve root block, which have good efficacy in preventin g surgical intervention. If the patient has no relief with in jection s, surgery sh ould be con sidered. Th e in dication s for surgery are less clear as th ere h ave been studies th at sh ow equal efficacy of operative an d n on operative treatm en t with lon g-term follow-up. Curren tly, surgery sh ould be considered for patients with unrem ittin g pain despite an adequate course of con servative th erapy, wh ich is at least 6 weeks. Th ese patien ts n eed to h ave symptom s of leg pain, not m erely back pain, for predictably good surgical results. Prior to surgery, an MRI (or CT myelogram for th ose who cannot have an MRI) should be obtained if n ot already don e to con firm th e diagn osis of a h ern iated disk. In th e properly selected patien t, with th e appropriate h istory, physical exam in ation , an d con firm in g MRI or th e equivalen t, surgery is over 90% successful. Surgery in volves discectomy or m icrodiscectomy at th e affected level. Th e lon g-term progn osis for disk h ern iation is quite good. It has been shown th at between 85% and 90% of surgically and non surgically treated patien ts are asymptom atic at 4 year. Less than 2% of both groups rem ain ed symptom atic after 10 years.

Spinal Stenosis Spin al sten osis can be defin ed as a n arrowin g of th e spin al canal secondary to degen erative, developm ental, or congen ital con dition s. Th e degree of m ech an ical pressure on the neural elem ents within the canal depends directly upon the degree of n arrowing. It m ust be realized that every person will h ave som e degree of narrowing with age secon dary to osteoarth ritis; h owever, n ot everyon e will h ave symptom s. Th e m ost com m on form of spin al sten osis is degen erative stenosis secondary to the effects of osteoarth ritis on the aging spine. The stenosis is due to a com bination of ch anges in osseous anatomy as well as soft-tissue hypertrophy. Th e typical sequen ce of even ts results from disk degen eration due to loss of water con ten t th at leads to segm en tal instability as loss of disk height results in m otion within the


spinal colum n secondary to a disruption of th e biom ech anics. Segm ental instability, or m otion between vertebral levels, leads to overridin g facets, facet join t hypertrophy, osteophyte form ation , hypertrophy of th e ligam en tum flavum an d oth er ligam entous structures, and/ or m icrofractures. Th e ultim ate result is n arrowin g of th e cord secon dary to osteophytes an d/ or soft-tissue hypertrophy. Th is usually results in nerve root im pin gem en t or sym ptom atic stenosis at the lateral recess, th ough less com m only impingem ent can occur in th e neural foram en an d centrally. Spin al sten osis affects aroun d 2% to 10% of th e population. The typical patient with lum bar stenosis is over the age of 50 when they first experien ce symptom s beginning with vague pain s in th e lower back, wh ich slowly progress to dysesth esias an d paresth esias down th e legs durin g am bulation . Th e sym ptom s gradually in crease in n ature with worsen in g pain an d/ or pain after m in im al walkin g to pain wh ile stan din g. Th ese n eurogen ic claudication symptom s will abate wh en th e patien t sits or lies down , th ough th e pain usually takes m ore tim e to abate th an claudication secon dary to peripheral vascular disease. Am bulation and stan ding typically exacerbate th e symptom s because th ose actions result in hyperextension of the lum bar spine, which further narrows an already diseased region . Sittin g or lying supine results in a m ore kyphotic lum bar spine and th us relieves th e pressure by en largin g th e sten otic region s. For this reason, m any of these patients will walk with their sh oulder h un ched forward over or anterior to th e pelvis, thereby increasing kyph osis. With m aturation of th e syn drom e, sym ptom s m ay even occur at rest. Muscle weakn ess, atrophy, an d asym m etric reflex ch an ges m ay th en appear; h owever, as lon g as the symptom s are on ly aggravated dynam ically, neurologic ch anges will occur only after the patient is stressed. For th is reason , m ost of th ese patien ts will h ave an absen t SLRT as opposed to patien ts with an acute h ern iated disk. Th e physical exam ination of these patients will therefore be un rem arkable other than n onspecific fin dings in the m ajority of cases. The following stress test can be used in an outpatient clinic; after a neurologic exam in ation has been perform ed on th e patien t, h e/ sh e is asked to walk up an d down th e corridor un til symptom s occur or the patient h as walked 300 feet. A repeat exam in ation is th en don e, an d in m any cases, th e second exam ination will be positive for a focal neurologic deficit when the first was negative. While h elpful if positive, this test does not rule out sten osis if negative. Plain x-rays sh ould be obtain ed wh en on e suspects spinal stenosis and generally are h elpful in visualizin g stenosis, especially if it is degen erative. Th e typical findings are intervertebral disk degeneration or loss of h eigh t, decreased in terpedicular distan ce, a decreased sagittal can al diam eter, an d facet degen eration . Th ese are also visualized well on CT scan (Fig. 12.26). If a patien t fails con servative treatm en t and becom es a surgical can didate, the location and degree of neurologic compression can be assessed with MRI and/ or CTscan, depen ding on wh ether th e

477

compression is osseous or of soft tissue origin. Typically, preoperative plan n in g will con sist of both if th e patien t is able to obtain all vital pieces of in form ation before proceeding. Th e m ajority of patien ts with spin al sten osis can be treated n on operatively with NSAIDs or th e application of a lum bosacral corset. Th ese patien ts also n eed to be educated about th e n atural h istory of th eir disease an d activity m odification . Non operative treatm en t is preferable as lon g as th e pain is tolerable for th e patien t. In dication s for surgery include intractable pain , worsen ing neurologic deficit, an d in ability to cope with fun ction al lim itation s. Surgical in terven tion in cludes lam in ectom y, lam in oplasty, lim ited lam in otomy, an d posterior fusion of varyin g levels.

Spondylolisthesis Spondylolisthesis refers to the forward displacem ent of on e vertebra on another. It can occur from a variety of causes and th us can be classified as congenital, isthm ic, degen erative, traum atic, pathologic, and postoperative. The m ost frequent causes are degen erative and isthm ic, though degen erative m ost com m on ly occurs in adulth ood. Isth m ic spon dylolisthesis, on th e other hand, begins in childhood and adolescen ce, although m any tim es it will not present un til adulth ood. Isth m ic spon dylolisth esis occurs secon dary to spon dylolysis, which m eans a defect in the area of the vertebra known as the pars interarticularis. Approxim ately 5% to 6% of th e population h as a defect in th e pars. Th e reason for th is is not completely understood, although it is believed to result from a fatigue-type fracture that develops in childhood. Som e of these patients will rem ain asymptom atic, though som e will progress to develop spondylolisthesis secondary to a degree of instability from the pars defect with subsequen t subluxation or an terior displacem en t (listh esis) of on e vertebra on to an oth er. Th e m ost com m on areas affected are L5 –S1, followed by L4 –L5, and L3 –L4. As alluded to earlier, spondylolysis occurs in childhood, while the even tual developm en t an d m an ifestation s of spon dylolisth esis can occur in ch ildh ood, adolescen ce, or adulth ood. Th e correlation between spon dylolysis or spon dylolisth esis an d back pain is n ot clear, an d th ere are con flictin g findings in the literature. Sarasate et al. found radiographic eviden ce of disk degen eration an d a slip of greater th an 10 m m correlated positively with sym ptom s as did a low lum bar index, increased lum bar lordosis, and spondylolysis at L4. It is important to be aware when evaluating th e patient with back pain and radiographic evidence of spon dylolisth esis, h owever, th at th is con dition m ay be n on -pain ful an d th at th ere are m any oth er poten tial sources of pain . Leapin g to the conclusion that spondylolisthesis, as seen on plain film s, is the source of th e patient’s pain m ay lead to unsuccessful treatm ent. Pain in the adult patient with spon dylolisthesis h as several potential sources, an d each sh ould be con sidered before determ ining th at the pain is secondary to th e slip.

478


A

B

C

D Figure 12.26 Spinal stenosis. (A) Axial CT scan showing the central region (A), lateral recess (B), and foraminal regions (C). (B) Axial CT scan showing facet degeneration with hypertrophy and resultant lateral recess stenosis. (C) Normal sagittal CT scan showing foraminal dimensions. (D) Sagittal CT scan showing foraminal encroachment due to degenerative changes. (Reproduced with permission from Frymoyer JW, Wiesel SW, An HS, et al. The Adult and Pediatric Spine, 3rd ed. Philadelphia: Lippincott Williams & Wilkins, 2003.)


Th e reason for pain secon dary to spon dylolisth esis is un clear, but suggested sources in clude segm en tal in stability and disk degeneration. Disk degeneration is m ore com m on in individuals with isthm ic spondylolisth esis, at the level of the slip, and is associated with the presen ce of lowback pain in th ese patien ts. Leg pain is frequen tly presen t in th e adult population with isth m ic spon dylolisth esis. Narrowin g of th e in tervertebral foram en due to disk bulgin g, hypertrophy of th e fibrous reparative tissue at th e lysis, an d a bony beak extending in to the foram en from th e proxim al stum p of the pars all con tribute to foram inal stenosis an d compression of th e exitin g n erve root, resultin g in radicular symptom s. Degen erative spon dylolisth esis is m ost com m on at th e L4 –L5 level and is seen in the sam e patien t population as spin al stenosis as both en tities have the sam e underlyin g etiology, th ough with som ewh at differen t en d results. In terestin gly, as opposed to spin al sten osis, spon dylolisth esis occurs m ore com m only in wom en , which is th ought to be secon dary to in creased ligam en tous laxity. Th e degen erative ch an ges in spon dylolisth esis even tually ren der th e vertebral colum n unstable to varying degrees, resulting in th e displacem en t of on e vertebra over an oth er. It m ust be noted th at anterolisthesis or forward displacem en t occurs m ost com m only, though retrolisthesis can occur as well. Following th e com m on them e with spinal conditions, patients with spondylolisth esis present in a variety of ways, from completely asymptom atic to sufferin g from debilitating pain. The m ost com m on presenting symptom s with degen erative spon dylolisth esis are lower back pain , n eurogenic claudication , an d radiculopathy. As m any patien ts are asymptom atic with degenerative spon dylolisthesis, again, it is absolutely essential to consider the possibility of anoth er source of pain . Also, as with isth m ic spon dylolisth esis, th e reason th is con dition is pain ful is n ot en tirely clear, but likely secon dary to segm en tal in stability an d disk degen eration . Radiculopathy an d n eurogen ic claudication , on th e oth er h an d, result from n arrowin g of th e in tervertebral foram en due to disk protrusion , soft-tissue hypertrophy, or a ch ange in osseous anatomy, as discussed in previous section s. Th e h istory an d physical exam in ation of th ese patien ts regardless of th e type of listh esis sh ould focus on th e exact location, source, and radiation pattern s of the patient’s pain . Patien ts often report a catch in g pain in th e lower back when risin g from a ch air. O n physical exam in ation , th is represen ts on e of th e m ost com m on fin din gs reproduced as lim ited extension with a painful catch on forced extension in patients with isthm ic spondylolisth esis, wh ile th ere is full forward flexion. Other findings on physical exam ination that can be useful include a stooped posture, hip flexion contracture, and spinal m uscle atrophy. Addition ally, som e patients will have a palpable step-off from th e displacem en t on on e segm en t to an oth er. Physical exam ination m ay reveal m ild L5 findings in the patien t with L5 – S1 spondylolisth esis, although th e neurologic exam ination

479

Figure 12.27 Degenerative spondylolisthesis lateral upright

lumbar radiographs demonstrating instability at L4–L5 with approximately 30% slip of L4 anteriorly on L5. (Reproduced with permission from Chapman MW. Chapman’s Orthopaedic Surgery, 2nd ed. Philadelphia, Lippincott Williams & Wilkins, 1993.)

is frequen tly n orm al an d SLRT is rarely positive. It m ust be kept in m ind that m any tim es the physical exam ination will be n on specific, but ideally th e h istory, exam in ation , and radiographic fin dings sh ould all correlate. Radiograph ic evaluation in itially in cludes stan din g AP and lateral radiographs that dem onstrate variable subluxation of one segm en t (Fig. 12.27) on another and/ or a pars defect in th e case of isth m ic spon dylolisth esis. Eigh ty percen t of pars defects can be visualized on plain lateral radiograph s, an d th e presen ce an d exten t of forward slippage is best defin ed on th is view. Often , flexion an d exten sion views are th en obtained to assess the stability of the slip by evaluating for m ovem ent with each view. Myerding proposed th e followin g classification to assess slip severity: Grade I—25% slip; Grade II—50% slip; Grade III—75% slip; and Grade IV—100% slip or greater. Complete slips (Grade IV) are referred to as spon dyloptosis. Addition ally, CT scan , myelography, an d MRI can be used for furth er evaluation with MRI bein g th e m odality of ch oice as it provides th e m ost inform ation about the soft tissues. MRI accurately defin es th e in tervertebral foram en , n erve roots, hydration status of the disks adjacent to proposed fusion sites, disk h erniations, an d any occult defects in th e pars. MRI an d often CT, to better defin e bony ch an ges, are used prior to surgical con sideration and for preoperative plann ing. Th e n atural h istory of th e disease varies with th e in itial clin ical presen tation . Most patien ts wh o presen t with back pain do n ot progress an d can be treated n on operatively, wh ile th ose presen tin g with claudication an d radiculopathy often progress an d will even tually n eed surgery. An in itial regim en of nonoperative therapy is indicated for alm ost

480


all patien ts, except th ose with sign ifican t n eurologic deficits. Non operative treatm en t con sists of NSAIDs, activity m odification , an d physical th erapy with a focus on back stren gth en in g, aerobic con dition in g, an d, especially, flexion exercises. A significant num ber of patients will respond to this regim en, although som e will ultim ately fail to fin d relief an d require surgical in terven tion . The indication s for surgical in terven tion include persisten t an d in tolerable back or leg pain despite a trial of n on operative th erapy; worsen in g n eurologic sym ptom s; an d bowel/ bladder sym ptom s, suggestive of cauda equin a syn drom e. Th ere are m ultiple surgeries depen din g on th e type an d severity of dysfun ction with all h avin g th e com m on them e of arth rodesis. Standard practice is to fuse in situ without reduction, un less th e patien t is experiencing neurologic comprom ise or th e patien ts h as a complete slip (spon dyloptosis). However, th ere are th ose wh o n ow h ave tren ded toward reducin g lesser slips. The results of fusion are affected by sm oking status, degree of slippage, type of fusion selected, an d th e use of eith er in tern al or extern al im m obilization . Kim an d associates reported a significantly higher success rate wh en an terior an d posterior fusion were perform ed an d wh en cast im m obilization was used following surgery. Improved functional outcom e was reported by Hanley and Levy in adults with isth m ic spon dylolisth esis in n on compen sation cases, wom en, patien ts with back pain only, nonsm okers, an d absen ce of a pseudarth rosis.

Cauda Equina Syndrome Cauda equin a syn drom e is a h igh ly discussed, th ough un com m on, condition resultin g from a large acute compression of th e nerve roots in th e lum bar spine that m ake up th e cauda equina resulting in a clinical syndrom e with variable am oun ts of back pain , sciatica, lower extrem ity weakn ess, saddle anesthesia, num bness, and bowel/ bladder dysfun ction . For th e diagn osis to be m ade, th e patien t m ust h ave urin ary sym ptom s th at usually begin as reten tion , followed by incontinence. The compression generally results from a m ech an ical com pression often by a large h ern iated disk m ost com m on ly at L4 –L5 but can also result from compression from epidural h em atom a, epidural abscess, traum a, an d tum or to n am e a few. Addition al dam age to th e roots can occur by venous congestion and ischem ia as well. The signs and symptom s of cauda equina syn drom e are a complex m ixture of low-back pain , bilateral m otor weakness of th e lower extrem ities, bilateral sciatica, saddle an esth esia, an d occasion ally fran k paraplegia with bowel an d bladder in con tin en ce or urin ary reten tion . As m en tion ed previously, urin ary reten tion or in con tin en ce m ust be presen t for a diagn osis of cauda equin a syn drom e. Th ese patien ts sh ould un dergo an im m ediate defin itive diagn ostic test, usually an MRI, an d, if it is positive, surgical decompression with in 24 to 48 hours, usually as em ergently as possible. Th ere, h owever, h ave been n o studies sh owin g improved results from decompression with in th e first 24

h ours com pared with in th e first 48 h ours, but th ere have been m ultiple studies sh owin g im proved results with in th e first 48 hours compared with m ore than 48 hours from the on set of symptom s. Th e prin cipal reason for prompt surgical in terven tion is to arrest the progression of the neurologic loss with hopeful return of fun ction, although this is variable and often incomplete. Although the incidence of cauda equina syndrom e in th e en tire back pain population is very low, it is th e only event that requires im m ediate operative intervention; if its diagnosis is m issed, th e con sequen ces can be devastatin g resultin g in loss of bowel an d bladder fun ction , paraplegia, an d even death .

LUMBAR SPINE ALGORITHM As with patients with neck pain, the task of the physician wh en con fron ted with low-back pain patien ts is to in tegrate their complaints into an accurate diagnosis and to prescribe appropriate therapy. This problem (the un iverse of lowback pain patien ts) h as been form ulated in to an algorith m , the aim of which is to select the correct diagnostic category an d proper treatm ent aven ues for each patient with lowback pain . A specific patien t m ay fall outside of th e lim its of th e algorith m an d require a differen t approach , an d th e physician m ust con stan tly be on th e alert for exception s. Th e algorith m can be followed in sequen ce (Fig. 12.28). Th e in form ation n ecessary to use th e algorith m in itially is obtained th rough the h istory and physical exam ination. Th e key poin ts in th e h istory are differen tiation of back pain th at is m ech an ical in n ature from n on m ech an ical pain that is present at rest, detecting changes in bowel or bladder fun ction , an d defin in g th e precise location an d quality of th e pain . Th e physical exam in ation m ust be orien ted toward rulin g out oth er m edical causes of low-back pain , assessing neurologic fun ction, and evaluating for the presen ce of ten sion sign s. Followin g th e low-back pain algorith m , th e first m ajor decision is to m ake a rulin g on th e presen ce or absen ce of cauda equina syndrom e. Mechanical compression of the cauda equina, with truly progressive m otor weakness, is the only surgical em ergen cy in lum bar spine disease. This compression , often from a m assive rupture of the L4 –L5 disk in th e m idlin e, is usually due to pressure on th e caudal sac, th rough wh ich pass th e n erves to th e lower extrem ities, bowel, and bladder. Patients thought to have cauda equin a syn drom e n eed em ergen t im agin g (MRI) followed by surgical intervention within the first 24 to 48 h ours. Th e rem ain in g patien ts m ake up th e overwh elm in g m ajority. Th ey sh ould be started on a course of con servative therapy, regardless of the diagnosis. At th is stage, the specific diagnosis, wh eth er a hern iated disk or simple back strain, is n ot important to th e therapy because the entire population is treated in a sim ilar way. A few of th ese patients will eventually need an invasive procedure, but at

481

POLYMYALGIA RHEUMATICA

NO

NO

FIBROSITIS

YES

ESR

YES

MUSCLE PAIN STIFFNESS

NO

MEDICAL EVALUATION

NO

BONE SCAN

NO

PSYCHO SOCAL EVALUATION

NO

LOW BACK SCHOOL YES

TUMOR INFECTION

YES

YES

DEGENERAT

TREATMENT AS INDICATED

PLB

INSTABILITY

SURGERY

MYELOGRAM +

NO

EPIDURAL STEROIDS

Figure 12.28 Lumbar algorithm.

SURGERY

NO

SUPPORT

YES

CAT/MRI SCAN

NO

LOCAL INJECTION

POSTERIOR THIGH PAIN

FULL ACTIVITY

EXERCISE

YES NO

YES

YES

BACK STRAIN PROTOCOL

(SONOGRAM)

CAT SCAN

NO

NO

IVP

NO

HIP AND HERNIA EVALUATION

YES

SUPPORT

CT/MRI OR MYELOGRAM

ANTERIOR THIGH PAIN

YES

YES

CONTROLLED PHYSICAL ACTIVITY (UP TO 6 WEEKS) MEDICATIONS NO

ACUTE CONSTITUTIONAL SYMPTOMS

CEC (PROGRESSIVE WEAKNESS)

ISOLATED STENOSIS L3-4 OR L4-5

YES

FULL ACTIVITY

BACK STRAIN PROTOCOL

FULL ACTIVITY

EXERCISE

SPONDYLOLISTHESIS CPPD OR OCHRONOSIS SEGMENTAL INSTABILITY

YES

PLAIN X-RAY (MOTION STUDIES)

PREDOMINANT

CALCIFICATION

DISC

OSTEOARTHRITIS ACROMEGALY

FULL ACTIVITY

FULL ACTIVITY

EXERCISE

YES

LOCAL INJECTION AND/OR SUPPORT

BACK STRAIN

PERIODIC REEVALUATION

NO

THERAPEOTIC INTERVENTION

DIAGNOSTIC TEST

SYMPTON OR SIGN

LOWER BACK PAIN ALGORITHM

LBP (SCIATICA)

ABDOMINAL ANEURISM

KIDNEY DISORDER

ARTHRITIS HERNIA

EXERCISE

MEDICAL EVALUATION

NO

MYELOGRAM +

NO

HNP

INVASIVE PROCEDURE: SURGERY/ CHEMONUCLEOLYSIS

YES

SCAT CAT/MRI +

NEURO/ TENSION SIGNS +

NO

EPIDURAL STEROIDS

YES

FULL ACTIVITY

LEG PAIN BELOW KNEE PREDOMINANT

YES

EXERCISE

SURGERY

SURGERY

SPINAL STENOSIS

MYELOGRAM +

CAT SCAN +

PLAIN XRAYS +

STRESS TEST +

NEURO/ TENSION SIGNS –

FULL ACTIVITY

482


this point, there is no way to predict which in dividuals will respon d to con servative th erapy an d wh ich will n ot.

Conservative Treatment Th e vast m ajority in th is in itial group h ave n on radiatin g low-back pain , term ed lum bago or back strain . Th e etiology of back strain is n ot clear. Th ere are several possibilities, in cludin g ligam en tous or m uscular strain , con tin uous m ech an ical stress from poor posture, facet join t irritation , or a sm all tear in th e an n ulus fibrosis. Patien ts usually com plain of pain in th e low back, often localized to a sin gle area. O n physical exam in ation , th ey dem on strate a decreased range of lum bar spine m otion, tenderness to palpation over th e in volved area, an d paraspin al m uscle spasm . Th eir roen tgen ograph ic exam in ation s are usually n orm al, but if therapy is n ot successful, film s should be obtained to rule out oth er possible etiologic factors. Two exception s to th is rule are patients youn ger than 20 years and patients over 60 years; x-rays are important early in the diagnostic process for th ese patients because they are m ore likely to h ave a diagnosis other than back strain (tum or or infection). O th er situation s warran tin g x-rays soon er rath er th an later in clude a h istory of serious traum a, kn own can cer, un explain ed weigh t loss, or fever. The early stage of treatm ent of low-back pain (with or without leg pain ) is a waitin g gam e. Th e passage of tim e, the use of an ti-inflam m atory m edication, and controlled physical activity are th e m odalities th at h ave proved safest an d m ost effective. Th e vast m ajority of th ese patien ts will respon d to th is approach with in th e first 10 days, alth ough a sm all percentage will not. In today’s society with its em ph asis on quick solution s an d “h igh tech n ology,’’ m any patien ts are push ed too rapidly toward m ore complex (i.e., in vasive) m an agem en t. Th is “quick fix’’ approach h as n o place in th e treatm en t of low-back pain . Th e physician treats th e patien t con servatively an d waits up to 6 weeks for a respon se. As already stated, m ost of th ese patien ts will improve with in 10 days, alth ough a few will take lon ger. O n ce th e patien ts h ave ach ieved approxim ately 80% relief, th ey sh ould be m obilized with th e h elp of a ligh tweigh t, flexible corset. After th ey becom e m ore com fortable and have in creased their activity level, they should begin a program of isom etric lum bar exercises an d return to th eir n orm al lifestyles. Th e path way alon g th is section of the algorithm is a two-way street; should regression occur with exacerbation of sym ptom s, th e physician can resort to m ore strin gen t con servative m easures. Th e patien t m ay require furth er bed rest. Most acute low-back pain patien ts will proceed along th is pathway, returning to a norm al life pattern with in 2 m on th s of th e on set of sym ptom s. If the in itial conservative regim en fails and 6 weeks h ave passed, sym ptom atic patien ts are sorted in to four groups. Th e first group comprises th ose with low-back pain predom in atin g. Th e secon d group com plain s m ain ly of leg pain , defin ed as pain radiatin g below th e kn ee an d com -

m only referred to as sciatica. The third group h as anterior th igh pain an d th e fourth group h as posterior th igh pain . Each group follows a separate diagn ostic path way.

Refractory Patients with Low-Back Pain Patients who contin ue to complain predom in antly of lowback pain for 6 weeks sh ould h ave plain x-rays carefully exam in ed for abnorm alities. Spondylolysis with or without spon dylolisth esis is th e m ost com m on structural abnorm ality to cause significan t low-back pain. Approxim ately 5% of th e population h as th is defect, th ough t to be caused by a com bin ation of genetics and environm ental stress. In spite of th is defect, m ost people are able to perform their activities of daily living with little or no discom fort. When sym ptom s are presen t, these patients will usually respond to n on operative m easures, in cludin g a th orough explan ation of the problem , a back support, and exercises. In a sm all percen tage of such cases, conservative treatm ent fails an d a fusion of the in volved segm ents becom es necessary. Th is is on e of th e few tim es prim ary fusion of th e lum bar spin e is in dicated, an d it m ust be stressed th at it is a relatively in frequen t occurren ce. Th e vast m ajority of patien ts with pain predom in an tly in the low back will have norm al plain film s. Th e diagnosis at this point is back strain. Before there is any additional workup, a local in jection of steroids an d lidocain e m ay be tried at the point of m axim um tenderness, known as a trigger poin t in jection . Th is m edication can be quite successful, an d if there is a good response, the patient is begun on exercises, with gradual resumption of norm al activity. In som e instances, if there are no objective findings, a “trigger poin t’’ injection can be considered as early as th e third week after on set of sym ptom s. Sh ould th e patien t n ot respon d to local in jection , oth er path ology m ust be seriously sough t. Abon e scan or an MRI, along with a general m edical evaluation, should th en be obtain ed. Th e bon e scan is an excellen t tool, often iden tifyin g early bon e tum ors or in fection s n ot visible on routin e radiograph ic exam in ation . It is particularly im portan t to obtain on e or both of th ese studies in th e patien t with n on m ech anical back pain. If the pain is constant, un rem itting, an d un relieved by postural adjustm en ts, m ore often th an n ot the correct diagnosis will be one of an occult neoplasm or m etabolic disorder not readily apparent from other testin g. Approxim ately 3% of cases of apparent low-back pain that present at orthopedic clinics are attributed to extraspinal causes. A thorough m edical search frequen tly reveals problem s m issed earlier such as a posterior penetrating ulcer, pan creatitis, renal disease, or an abdom inal an eurysm . If these diagn ostic studies are positive, the patient should be transferred into a nonorth opedic treatm ent m ode and would no longer be in the therapeutic algorithm . Patien ts who h ave no abnorm ality on their bone scan or MRI an d do n ot sh ow oth er m edical disease as a cause for th eir back pain are then referred to another type of


therapy—the low-back school. It is believed that m any of these patients are suffering from discogenic pain or facet join t pain syn drom e. Th e low-back sch ool con cept h as as its basis the belief that patients with low-back pain, given proper education and understandin g of their disease, can often return to a productive an d fun ction al life. Ergon om ics, th e proper an d efficien t use of th e spin e in work an d recreation , is stressed. Back sch ool n eed n ot be an expensive proposition. It can be a one-tim e classroom session with a review of back problem s and a dem on stration of exercises with patien t participation. This type of education al process h as proved to be very effective. It is m ost important, however, that before they are referred to this type of program , patients are thoroughly screened. One does n ot wan t to be in th e position of treatin g a m etastatic tum or in a classroom . If low-back sch ool is n ot successful, th e patien t sh ould un dergo a th orough psych osocial evaluation in an attem pt to explain th e failure of th e previous treatm en ts. Th is is predicated on th e kn owledge th at a patien t’s disability is related not only to his or her pathologic anatomy but also to his/ her perception of pain and stability in relation to th e social environm ent. It is quite com m on to see a stable patient with a fran k h ern iated disk con tin ue workin g, regardin g th e disability as on ly a m in or problem , wh ile a hysterical patient takes to bed at the slightest twinge of back discom fort. Drug h abituation , depression , alcoh olism , an d oth er psych iatric problem s are seen frequen tly in association with back pain . If th e evaluation suggests any of th ese problem s, proper m easures sh ould be in stituted to overcom e the disability. Th ere are a surprising num ber of am bulatory patien ts addicted to com m on ly prescribed m edications using complaints of back pain as an excuse to obtain these drugs. Oxycodone, hydrocodone, and diazepam are the m ost popular offenders. Oxycodon e and hydrocodone are truly addictive; diazepam is both habituating and depressin g. Because th e complain t of low-back pain m ay be a com m on m anifestation of depression, it is counterproductive to treat such patients with diazepam . Approxim ately 2% of patien ts who initially present with low-back pain will fail treatm ent an d elude any diagn osis. Th ere will be n o eviden ce of any structural problem in th e back or criteria for an un derlyin g m edical disease or psych iatric disorder. This is a very difficult group to m anage. Th e authors’strategy h as been to discontin ue narcotics, reassure the patients, and periodically reevaluate them . Over tim e, on e-th ird of th ese patien ts will be foun d to h ave an un derlyin g m edical disease; th us, on e can n ot aban don th is group an d discon tin ue treatm en t. For th e rem ain der, as m uch physical activity as possible should be encouraged.

Refractory Patients with Sciatica Th e n ext group of patien ts is th ose with sciatica th at is pain radiatin g below th e kn ee. Th ese patien ts usually experien ce their symptom s secon dary to m echanical pressure and in -

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flam m ation of the nerve roots that originate in the back an d exten d down th e leg. Th e etiology of th e m ech an ical pressure can be soft tissue, such as a h ern iated disk, or bon e, or a com bin ation of th e two. At th is poin t in th e algorith m , th e patien t h as h ad up to 6 weeks of con trolled physical activity an d m edication but still h as persisten t leg pain . Th e n ext th erapeutic step is an epidural steroid in jection , wh ich is perform ed on an outpatien t basis. An epidural in jection is worth tryin g; th e ch an ce of success is aroun d 40% an d th e m orbidity rate is low, particularly compared with th e n ext step—surgery. Th e m axim um benefit from a sin gle in jection is achieved at 2 weeks. Th e in jection m ay h ave to be repeated on ce or twice, an d 4 to 6 weeks sh ould pass before its success or failure can be judged. If epidural steroids are effective in alleviatin g th e patien t’s leg pain or sciatica, th e patien t is begun on a program of back exercises an d en couraged to return promptly to as n orm al a lifestyle as possible. Sh ould th e epidural steroids prove in effective, an d 3 m on th s h ave passed sin ce th e in itial on set of sym ptom s with out relief of pain , som e type of in vasive treatm en t sh ould be con sidered. Th e patien t group is th en divided in to th ose with probable h ern iated disks an d th ose with symptom s secon dary to spin al sten osis or degen erative disease. Th e physician m ust n ow carefully reevaluate th e patien t for a neurologic deficit and for a positive tension sign or SLRT. For th ose wh o h ave eith er a n eurologic deficit or positive ten sion sign s alon g with con tin ued leg pain , an MRI scan sh ould be obtain ed. If th e MRI is clearly positive an d correlates with physical fin din gs, testin g is don e an d surgical in terven tion can th en be con sidered. If th ere is any question about th e fin din gs, on e sh ould proceed with eith er a CT scan or a myelogram to furth er evaluate. As in th e cervical spin e, th ere is repeated docum en tation th at for surgery to be effective in th e treatm en t of a h ern iated disk, th e surgeon m ust fin d un equivocal operative eviden ce of a n erve root compression . Accordin gly, n erve root compression m ust be firm ly substan tiated preoperatively, n ot on ly by n eurologic exam in ation but also by radiographic data. There is no place for “exploratory’’back surgery. Many asymptom atic patients have been found to h ave abn orm al myelogram s, EMGs, CT scan s, an d MRI scan s. If the patien t h as n either a neurologic deficit nor a positive SLRT, regardless of radiograph ic fin din gs, th ere is n ot en ough eviden ce of root com pression to proceed with surgery. These patien ts without objective findin gs are th e on es wh o h ave poor results. If th ere are n o objective fin din gs, th e physician sh ould avoid surgery and proceed to psych osocial evaluation. Exceptions should be few an d far between. When sympathy for th e patient’s complaints outweighs the objective evaluation , surgery is fraugh t with difficulties. For th ose wh o m eet th ese specific criteria for surgery, results will be satisfactory; 95% of th ese patients can expect to have a good to excellen t result.

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The second group of patien ts whose symptom s are on the basis of m echan ical pressure on th e neural elem ents are those with spinal stenosis. The diagnosis of spin al stenosis usually can be inferred from the plain x-rays, which will dem on strate facet degen eration , disk degen eration , decreased interpedicular distan ce, and decrease sagittal canal diam eter as previously reviewed. ACT scan or MRI scan can confirm the diagnosis. If symptom s are severe, and there is radiograph ic eviden ce of spin al sten osis, surgery is appropriate. Age alon e is n ot a deterren t to surgery; m any elderly people wh o are in good h ealth except for a n arrow spin al canal will benefit greatly from adequate decompression of the lum bar spine.

Refractory Patients with Anterior Thigh Pain A sm all percentage of patients will h ave pain th at radiates from the back into th e an terior thigh. This usually is relieved by rest an d an ti-in flam m atory m edication . If th e discom fort persists after 6 weeks of treatm en t, a workup sh ould be initiated to search for an un derlying disorder. Although an upper lum bar radiculopathy can cause anterior th igh pain , several other entities m ust be considered. A hip problem or hernia can be ruled out with a thorough physical exam in ation . If th e h ip exam in ation is positive, radiograph s sh ould be obtain ed. An IV pyelogram is useful to evaluate th e urin ary tract because kidn ey ston es often m ay presen t as an terior th igh pain . Periph eral n europathy, m ost com m on ly secon dary to diabetes, also can presen t in itially with an terior th igh pain ; a glucose toleran ce test an d EMG will reveal th e diagn osis. Fin ally, a retroperiton eal tum or can cause symptom s by m ech an ically pressin g on the nerves that innervate th e anterior thigh. A CT scan or MRI scan or the retroperitoneal area will elim in ate or confirm th is possibility. If any of the en tities reviewed here is diagnosed, the patien t is treated accordin gly. If n o physical cause can be found for anterior thigh pain, th e patient is treated for recalcitran t back strain by the m eth od already outlined.

Refractory Patients with Posterior Thigh Pain Th is fin al group of patien ts will complain of back pain with radiation in to the buttock an d posterior thigh . Most of th em will be relieved of th eir sym ptom s with 6 weeks of conservative th erapy. However, if their pain persists after the initial treatm ent period, they can be considered to have back strain an d given a trigger poin t in jection in th e area of m axim um ten dern ess. If th e in jection is un successful, it is necessary to distinguish between referred and radicular pain. As noted earlier, referred pain is the pain in m esoderm al tissues of th e sam e em bryologic origin . Th e m uscles, ten don s, an d ligam en ts of th e buttocks an d posterior th igh have the sam e em bryologic origin as the lower back. Wh en the lower back is injured, pain m ay be referred to the posterior thigh, wh ere it is perceived by the patient. Referred pain

from irritated soft tissues cannot be cured with a surgical procedure. Radicular pain is caused by compression of an in flam ed n erve root alon g th e an atom ic course of th e n erve. A hern iated disk or spinal sten osis in th e h igh lum bar area can cause radiation of pain in to th e posterior th igh . An MRI or CT scan and an EMG m ay be used in this situation to differen tiate radicular etiology from referred pain or a periph eral n erve lesion . If th e studies are with in n orm al lim its, the patien t is con sidered to h ave low-back strain an d treated according to the algorithm . If a radicular abn orm ality is found, the patient is diagnosed as having m echanical com pression on th e n eural elem en ts eith er from a h ern iated disk or spin al sten osis. Epidural steroids sh ould be tried first; if these drugs do not provide adequate relief, surgery sh ould be con templated. Th is group of patien ts with un explain ed posterior th igh pain is very difficult to treat. Th e biggest m istake is th e perform ance of surgery on people thought to have radicular pain but wh o actually h ave referred pain . Again , referred pain in th is settin g is n ot respon sive to surgery. In m ost in stan ces, th e treatm en t of low-back pain is n o longer a mystery. The algorithm described h ere presents a series of easy-to-follow and clearly defined decisionm aking processes. Use of this algorithm provides patients with th e m ost h elpful diagn ostic an d th erapeutic m easures at the optim al tim e. It neither denies them helpful surgery n or subjects them to procedures th at are useless technical exercises.

ADULT SCOLIOSIS Scoliosis is described as a coron al plan e curvature occurrin g m ost com m on ly in th e th oracic, th oracolum bar, an d lum bar spine. Although the frontal curve is th e m ost com m on ly recognized aspect of the deform ity, scoliosis is a three-dim ensional abnorm ality with alterations not only in the frontal plan e but also in th e sagittal an d axial planes, all contributing sign ifican tly to the cosm etic deform ity and m orbidity seen with this con dition. Adult scoliosis refers to scoliosis in th e skeletally m ature individual, in m ost series, beyon d th e age of 20. Th e prevalen ce of scoliosis, as well as th e severity of the curves identified, increases with increasin g age. Kostuik an d Bentivoglio reported on 5,000 patien ts undergoing IV pyelography, n otin g 3.9% of th ese in dividuals to h ave thoracolum bar or lum bar curves greater than 10 degrees. Th ey also n oted th at th e overall prevalen ce was probably som ewhat h igher, but chest radiographs were n ot included. Many authors have noted th e potential for de novo developm en t of scoliosis in m iddle-aged an d older patien ts secon dary to degen erative ch an ges, as well as th e ten den cy for m ild-to-m oderate curves in adolescence to progress slowly durin g adulth ood, leadin g to in creasin g prevalen ce an d severity as older patients are surveyed.


Wh en treatin g an adult patien t with scoliosis, th e etiology of th e curve is frequen tly related to th e age of th e patien ts. Youn g an d m iddle-aged adults frequen tly presen t with idiopath ic scoliosis th at m ay h ave been diagn osed in adolescence or m ay be newly identified. Older patients will be m ore likely to h ave n ewly diagn osed scoliosis secon dary to degenerative disease. In fact, the m ost com m on form of scoliosis is degenerative in nature. Patient presentation again varies with adult scoliosis, and often depends on the type of scoliosis, that is, idiopath ic versus degen erative. Som e patien ts h ave n o com plain ts, an d scoliosis is discovered as an in ciden tal fin din g, for example, on a chest x-ray. The m ost com m on presenting complain t for th e adult patien t with idiopath ic scoliosis is back pain , an d it is in cum ben t on th e physician to clearly identify the location of the pain, in particular whether it is related to th e curve or is th e m ore typical low-back pain . It is important to recognize that there is n o clear-cut correlation between th e presence of idiopathic scoliosis and back pain . Th e vast m ajority of th e pediatric population with idiopathic scoliosis present with painless deform ity. A certain percen tage of adults with idiopath ic scoliosis will develop persistent, at tim es worsenin g pain that is clearly related to th eir curve an d are good can didates for eith er nonsurgical or surgical treatm en t. On the oth er hand, m any patien ts with scoliosis presen t with n on specific low-back pain . In th ese in dividuals, treatm en t directed at th e curve, especially surgical treatm en t, is un likely to be effective. Curve progression m ay occur even in adulthood and is m ore likely in curves that are greater than 50 degrees at the tim e of skeletal m aturity, particularly right thoracic curves. Slow progression is seen , so it is important to compare curve m easurem en ts over a period of 5 or even 10 years to accurately identify possible curve progression. Although pulm on ary sym ptom s, an d even respiratory failure, h ave been reported in scoliosis, th e in ciden ce of objective respiratory in sufficien cy is really quite low. Fin ally, cosm esis is a sign ifican t con cern of m any patien ts with idiopath ic scoliosis. Th is is particularly true in the adult, although m any patien ts are reluctan t to iden tify th is to th e physician as a reason for seekin g treatm en t. Th e secon d an d m ore exten sive group of patien ts presen ts with degen erative scoliosis. Th ese patien ts are typically older and have only recently been diagnosed with scoliosis. The etiology of degenerative scoliosis is un certain, but it probably related to preexistin g sm all curves th at progress as a respon se to asym m etric degen eration an d collapse in the posterior facets and anterior disk thereby essentially destabilizin g the colum n . Significant spon dylotic changes are seen with associated rotation, coronal plane curvature, an d frequen tly loss of lum bar lordosis. Cen tral, lateral recess, and foram in al sten osis are com m on , th ereby leading to possible nerve root compression in the concavity of either th e prim ary lum bar or the lum bosacral fractional curve (opposite the prim ary curve). Th ese patients th erefore usually h ave a h istory of lon g stan din g, gradually

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worsen in g low-back pain an d seek treatm en t secon dary to a newer onset of symptom s typical of spinal stenosis secon dary to n erve root com pression .

Evaluation Evaluation of th e patien t with scoliosis in cludes h istory, physical exam in ation , an d radiograph ic studies. Th e h istory should focus on determ ining the chief complaint of th e patien t, wh eth er it is back pain , n eurogen ic claudication, loss of balance, or deform ity. If pain is the presen ting com plain t, on e m ust obtain a clear, detailed description of th e exact location of th e pain as well as radiation . Eviden ce of curve progression , such as loss of h eigh t or a n otable change, over the last few years, in the fit of clothing, is importan t. It is also important to ask about the patient’s subjective sense of balance. Physical exam in ation sh ould follow th e typical spin e physical exam in ation with focus on gait, balan ce, an d ran ge of m otion . Th e presen ce of a rotation al rib, flan k deform ity, or a leg length discrepancy should be noted. Neurologic testing seeking both upper and lower m otor neuron findings is carried out; it sh ould be noted that idiopathic scoliosis, as opposed to degen erative scoliosis, never results in spinal cord compression or paraplegia, and the presence of upper m otor n euron fin din gs such as clon us or a positive Babinski’s sign should trigger a search for intraspin al path ology. Radiograph ic evaluation in cludes stan din g PA (Fig. 12.29) an d lateral radiograph s of th e full spin e, ben din g film s when surgery is contemplated, and m ay include supin e views of th e lum bar region to better define degen erative ch an ges. Th e Cobb an gle is used to m easure curve severity an d docum en t progression . MRI sh ould be obtain ed in cases of rapid progression , any upper m otor n euron fin din g, or a h istory suggestive of lum bar stenosis. It sh ould be n oted th at th e abn orm al th ree-dim en sion al anatomy seen in scoliosis secondary to rotation an d curvature superimposed on the spondylotic changes present with degen erative scoliosis m ay m ake accurate diagn osis of th e site an d severity of sten osis difficult on MRI. Th erefore, CT is often obtained as well to better delineate the bony anatomy. Treatment Many patients with scoliosis presen t for evaluation and treatm ent of their backs, but only rarely is surgical treatm ent necessary. Accurate identification of the patien t’s m ajor source of concern will in m any cases lead to observation as th e appropriate form of m anagem ent. When treatm ent is in dicated, m any patients either have low-back pain , leadin g to n on operative m an agem en t in m ost cases, or h ave m ild-to-m oderate curve-related pain , wh ich will frequently respond to nonoperative treatm ent as well. Non operative treatm en t for low-back pain related to scoliosis essentially follows th e treatm ent protocol outlined earlier. Usually a program of weigh t reduction , aerobic

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Figure 12.29 Adult degenerative scoliosis. Note the coronal

plane curvature. The curve is secondary to degenerative changes from spondylosis. (Reproduced with permission from Chapman MW. Chapman’s Orthopaedic Surgery, 2nd ed. Philadelphia, Lippincott Williams & Wilkins, 1993.)

exercise, an d back stretch in g an d stren gth en in g exercises will relieve symptom s wh en com bined with NSAIDs. Oth er nonoperative options used less frequently are injections (i.e., trigger poin t, facet join t, or epidural steroid in jection s), tran scutan eous electrical n erve stim ulation (TENS), an d m edical m an agem en t of any m etabolic abn orm alities associated with scoliosis such as osteoporosis. Som e advocate the use of tricyclic an tidepressants for h elp with night pain an d gabapen tin or pregabalin for n eurogen ic pain , though success with these m edication s is less con sistent. Th e use of n arcotics, as h igh ligh ted in previous section s, is lim ited an d sh ould be prescribed on ly for sh ort-term use, if at all. O ccasion ally a custom -m olded th oracolum bosacral orth osis (TLSO) is utilized in an in dividual wh o is a poor surgical candidate. It sh ould be n oted that orthoses do n ot stop progression of the curve and are used prim arily to control symptom s. There are no stan dardized indications on when to operate on th ese patien ts, but for th e m ost part, surgery is reserved for patien ts with docum en ted curve progression , in tractable pain clearly related to th e curve itself, or a persisten t, un acceptable pain pattern secon dary to sten osis in a patien t with degen erative scoliosis. Cosm esis is rarely iden tified as th e prim ary in dication for surgical treatm en t, al-

th ough m any patien ts will attest to its im portan ce wh en question ed followin g surgery. Th e goals of surgery depen d on th e reason for th e operation but usually involve decompression and fusion , curve correction an d fusion , or a com bin ation of th e two, with emph asis on th e n eed for fusion in th ese patien ts to con trol pain an d preven t subsequen t curve progression followin g surgery. Virtually, all m odern scoliosis surgery in cludes fusion and in strum en tation utilizing pedicle screws, m ultiple h ooks, sublam inar wires, or com bin ation s with th e addition of bone graft. Approaches include posterior, anterior, or a com bin ation . Posterior fusion with instrum entation is indicated for m oderately severe curves, particularly flexible curves, and is m ost often employed in isolated thoracic curves. When a curve exceeds 60 to 70 degrees, is particularly rigid, or exten ds in to th e th oracolum bar an d lum bar spin e, isolated posterior fusion is in adequate leadin g to a h igh rate of pseudarth rosis. In th ese cases, a com bin ed an terior approach is best utilized. An terior in strum en tation an d an terior fusion is com m only used in isolation in youn ger patients with flexible th oracolum bar or lum bar curves in an attempt to save a distan t fusion level. It is m ost com m only utilized in com bination with a posterior approach, especially with m ore rigid curves. Results of surgery for scoliosis in th e adult depen d on a num ber of factors, including curve etiology, severity, patient age, and th e patient’s presenting complaint. Pain is th e m ost com m on in dication for surgery in adult scoliosis, but pain relief frequen tly is in adequate. Careful correlation of th e patien t’s com plain ts with th eir spin al deform ity, as well as establish in g realistic goals for th e surgery, offers th e best h ope for m in im izin g th is problem . Curve correction is certain ly less in adults than in adolescents, although this can be im proved utilizin g a com bin ed an terior an d posterior approach , in wh ich case curve correction of 40% to 50% is routin ely reported. Patien ts h ave an overall h igh satisfaction with cosm etic results, and this is particularly importan t to m any patients, although m ay not be th eir prim ary reason for obtain in g surgery. Com plication s from surgery occur approxim ately 20% of the tim e an d in clude a wide array of problem s from m ajor to m in or. Neurologic com plication s can occur, alth ough th ey are rare. Com plication s in clude pseudarth roses, woun d in fection , respiratory complication s, urinary tract in fections, hardware failure, jun ction al kyph osis, an d n eurologic in jury, am on gst oth ers. Overall, surgery can be successful in th e properly selected patien t, but proper patien t education and understandin g of the goals, lim itations, and risks of surgery m ust be establish ed prior to em barkin g on surgical treatm en t.

TUMORS OF THE SPINE Th e overwh elm in g m ajority of n eoplastic affliction s of th e spin e are m etastatic. Th e skeleton is the third m ost com m on


site of m etastatic deposit (after the lung an d liver), an d th e spine is the m ost com m on skeletal location for m etastatic disease. It h as been estim ated th at up to 70% of patien ts with dissem in ated can cer will h ave eviden ce of skeletal m etastasis on autopsy, and symptom atic disease of the spine is th e m ost frequen t clinically significant m an ifestation . Prim ary tum ors of th e spin e, on th e oth er h an d, are exceedin gly rare. Th eir occurren ce, h owever, exten ds over the entire age spectrum , and pain, deform ity, and paralysis can occur as a result of either benign or m alignant prim ary neoplasm s. For this reason, despite th eir relatively infrequen t appearan ce, th ese lesion s m erit review. Pain is the m ost com m on presenting complaint of patients with tum or of th e spine. Back pain alm ost always precedes n eurologic in volvem en t, an d a com m on progression of back pain, followed by radicular pain, followed by cord compression, and dysfun ction is seen. Other than the age of the patien t, very little in history or physical exam ination serves to differentiate the presen ce of a prim ary from a m etastatic tum or. Historical poin ts th at sh ould serve to alert the physician to the possibility of m etastatic disease as th e cause for a patient’s pain include age over 50; constitution al symptom s such as unexplained weight loss, fever, an d so on ; night pain; an d a history of prior m alignancy. Specific question in g about a previous diagn osis of can cer is necessary, even though m any would assum e such inform ation to be an obvious point in routine questioning about past m edical h istory. Addition ally, on e m ust be aware of th e distin ct possibility of late presen tation of skeletal m etastases, particularly in can cer of th e breast. When evaluatin g th e patien t with a kn own prim ary lesion of the spine, som e gen eralization s can be m ade regarding the differentiation between benign and m alignan t disease. Youn ger patien ts are m ore likely to h ave a ben ign spinal neoplasm , whereas, after the age of 21, over 70% of prim ary tum ors are m align an t. As th e age group exten ds into older patien ts, it becom es apparent that the risk of m alignancy, either prim ary or secondary, is m arkedly in creased. Additionally, the location of th e lesion also gives a clue as to its histology. Most lesions of the vertebral body are m alignant includin g prim ary and m etastatic tum ors, wh ereas disease in volvin g th e posterior elem en ts is m ore likely to be ben ign . Evaluation of the patient with a possible spin al tum or begin s with th e h istory, con cen tratin g on th e poin ts just described. Careful questioning about th e location an d extent of th e pain as well as activities an d position s th at exacerbate an d am eliorate the symptom s is essential. In addition , constitution al symptom s are reviewed, and questionin g about bowel an d bladder fun ction is carried out; bowel an d bladder dysfun ction m ay be seen in cases of cord com pression an d m ay, on occasion , precede back pain . On physical exam in ation, tenderness, spasm , deform ity, and the presence of a m ass are sough t. Most importan t, a careful n eurologic exam in ation is perform ed. Th is assessm en t m ust in clude sen sory an d m otor testing along th e trunk to determ in e a

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subtle sen sory pinprick level. The presence or absence of upper m otor n euron fin din gs sh ould be ascertain ed. Radiograph ic evaluation in cludes plain film s, scin tigraphy, CT scan n in g, an d MRI. Plain radiograph s are routin ely obtain ed, alth ough th ey are relatively in sen sitive to th e presen ce of eith er prim ary or secon dary n eoplasm . Plain film fin din gs th at m ay be presen t in clude path ologic com pression fracture, lysis of a vertebral body, or deform ity. O n AP views, involvem ent of a pedicle, with destruction of its cortical bone, m ay lead to the “winkin g owl sign.’’Although m ost m etastatic lesion s arise from th e vertebral body, it h as been well docum en ted th at plain radiograph ic eviden ce of bony destruction in th e vertebral body is n ot apparen t un til som ewh ere between 30% an d 50% of the trabecular bone h as been destroyed. In m any cases, th e tum or spreads before this point in to th e pedicle, where destruction of the m ostly cortical bon e leads to early radiograph ic iden tification of th e absen t pedicle. For the reasons discussed earlier, plain film s are not very sen sitive at screen in g for tum ors. O n th e oth er h an d, tech n etium -99 bon e scan n in g is a h igh ly sen sitive test for screen in g th e skeleton for m etastatic or any neoplastic disease. Th ese lesion s appear as in creased uptake on bon e scan nin g with th e exception of m ultiple myelom a and oth er aggressively lytic lesion s th at m ay appear cold. Although relatively nonspecific in differentiating tum or from in fection or fracture, routin e bon e scan n in g is used as a surveillan ce m ethod to detect early m etastases. Metastatic lesion s will appear on a bon e scan from 3 to 18 m on th s prior to plain film s. Bon e scan s also provide th e added ben efit of scan n in g th e wh ole body to see if th ere are oth er lesion s. Because of its lack of specificity, bon e scan n in g h as largely been replaced by MRI, but th ere still rem ain s a large ben efit from bon e scan n in g especially wh en screen in g for distan t m etastatic lesion s. CT scanning with or without myelography can be used to m ore clearly delin eate th e cross-section al bony an atomy an d exten t of bony destruction in volved, wh ile to a lesser exten t evaluate th e exten t of cord com pression or n eural impin gem en t. MRI h as largely supplan ted CT in th e evaluation of m ost m etastatic disease of th e spin e, but CT can be very h elpful in evaluatin g prim ary tum ors, particularly those in volving the posterior elem ents, and m ost clearly defin es th e path ologic bony an atom y. Addition ally, CT can be very h elpful for preoperative plan n in g. MRI h as evolved as the gold standard for im aging of the spine. Advantages include the lack of ionizing radiation , n on in vasiven ess, an d th e ability to iden tify m arrow replacem en t pattern s, soft-tissue m asses, an d n eurologic compression. MRI is the m ost sensitive radiologic m ean s of evaluatin g n eoplastic disease, an d it is certain ly th e m ost specific m odality for differentiating tum or from infection. Th is com m on question is resolved, prim arily, by involvem en t of th e disk. Relatively resistan t to m etastatic spread by its lack of vascularity, th e disk is typically spared on plain radiography as well as on MRI in cases of m etastatic disease.

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O n th e oth er h an d, in fection , wh ich usually arises in th e vertebral body, rapidly spreads in to th e disk, an d exten sive destruction of th e disk is com m on ly seen on plain radiograph s an d MRI. Addition ally, alth ough n ot n ecessary in all cases, MRI can be en h an ced with addition of gadolin ium con trast to evaluate th e soft tissue, th e spin al can al, an d th e epidural space.

Primary Benign Tumors Prim ary tum ors of th e spin e can be differen tiated on th e basis of tissue origin , location , an d age of th e patien t. Softtissue or bony tum ors m ay be seen , an d th ese lesion s m ay arise prim arily in th e vertebral body or in th e posterior elem en ts. It is im portan t to kn ow th at ben ign tum ors of the spin e arise prim arily in the posterior elem en ts, while m align an t lesion s arise prim arily in th e vertebral body. In addition , th e age of th e patien t h as been dem on strated in several series to provide predictive value as to whether a benign or m alignant tum or is present, with adults m uch m ore likely to suffer from prim ary m align an cy th an ch ildren .

Osteoid Osteoma/Osteoblastoma O steoid osteom a an d osteoblastom a are tum ors of bony origin th at com m on ly arise in th e spin e, alm ost exclusively in the posterior elem ents. Th ese tum ors can be differen tiated from each oth er on th e basis of size, with osteoid osteom a con sistin g of a n idus less th an 2 cm an d osteoblastom a bein g greater th an 2 cm . Approxim ately 40% of osteoid osteom a an d 30% of osteoblastom as occur in the spin e, with both occurring m ost com m only in the secon d an d th ird decades. Both presen t as back pain , usually un related to activity. Osteoid osteom as occur m ost com m on ly in th e lum bar spin e, wh ile osteoblastom as occur m ost com m on ly in th e cervical spin e, th ough both can be found through out the spine. Radiograph ic dem onstration, particularly with th e sm aller osteoid osteom a, is difficult an d x-rays often appear n orm al. Wh en th is lesion is suspected an d film s are n orm al, tech n etium bon e scan n in g en ables localization of th e lesion th at is th en better defin ed by CT (Fig. 12.30). Both of th ese lesion s can result in pain ful scoliosis, wh ich is usually rapidly progressive an d rigid, an d th ese sh ould be con sidered wh en pain is the presenting complaint in a patien t with a spinal deform ity. O steoid osteom a m ore com m on ly results in scoliosis than osteoblastom a. As m entioned earlier, back pain is th e m ost com m on complain t with 30% of th ese patien ts experiencing th e pain at night. Classically, the pain in osteoid osteom a is relieved with aspirin or NSAIDs, th ough th is occurs on ly about 30% of th e tim e in th e spin e. Excision is the preferred treatm ent for both of these lesion s, though asymptom atic patients with osteoid osteom a can be m onitored. Intralesional curettage and bone graftin g as n eeded result in excellen t pain relief with sm all recurrence rates in osteoid osteom a, while recurrence rates

Figure 12.30 Osteoblastoma. Radiographic appearance of an osteoblastoma (cross-sectional CT scan through the L5 lesion). The lesion is larger than the osteoid osteoma, and there is a significant soft-tissue mass extending into the spinal canal. (Reproduced with permission from Frymoyer JW, Wiesel SW, An HS, et al. The Adult and Pediatric Spine, 3rd ed. Philadelphia: Lippincott Williams & Wilkins, 2003.)

ten d to be h igh er with th is treatm en t for osteoblastom a. Th erefore, m ost osteoblastom as are treated by wide excision if possible. The best in dication for successful excision of th ese lesion s is th e relief of pain followin g treatm en t. On occasion, an osteoblastom a will destroy en ough of th e posterior arch an d associated facet join t so as to require stabilization , particularly when seen at the thoracolum bar jun ction , but th is is relatively un com m on . Fin ally, wh en recogn ized early, pain ful scoliosis resultin g from th ese en tities will usually resolve. If scoliosis persists, surgical indications and tech niques m irror those for idiopath ic scoliosis.

Aneurysm Bone Cyst Aneurysm al bone cyst is a less com m on lesion affecting the spin e. Most lesion s arise in the posterior elem ents, but up to 40% exten d in to th e vertebral body. Pain is th e typical presen tation occurrin g in approxim ately 95% of patien ts. Radiograph ically, a lytic, fairly exten sive lesion is seen , an d it m ay involve m ore than one level. MRI with gadolin ium con trast typically shows septa with fluid –fluid levels. The treatm ent in volves excision that, in m any cases, consists of in tralesion al curettage followin g em bolization , with recurrence rates of approxim ately 10% to 15%. Recurrence is treated with repeat curettage. Hemangioma At autopsy, approxim ately 10% of individuals will have evidence of hem angiom a som ewhere in the spinal colum n, m akin g hem angiom a the m ost com m on benign neoplasm


of th e spin e. Most of th ese lesion s are silen t clin ically, an d the correlation between th e presence of a hem angiom a and back pain is th erefore un certain . Th ough m ost ben ign lesions occur in th e posterior elem ents, hem angiom a m ost com m only occurs in the vertebral body, though approxim ately 10% appear in th e posterior elem ents. The diagnosis of vertebral body h em angiom a is typically m ade on plain radiograph s, in wh ich in creased trabecular striation s an d a “jailhouse vertebrae’’appearance m ay be seen. Differen tiation from Paget’s disease, wh erein th e vertebral body will actually be en larged, sh ould be possible on plain radiography. CT an d MRI scan will sh ow, on axial im ages, a pun ctuate appearan ce to th e th icken ed trabeculae with th e addition of a high signal seen on T2-weighted MR im ages. Occasion ally, a hem angiom a will present with a soft-tissue m ass, although neurologic impairm ent is rare. Hem an giom as are treated sym ptom atically. Therefore, m ost do n ot require any therapy. In those with symptom atic h em an giom as, we h ave h ad success with alcoh ol scleroth erapy in which eth an ol is injected in to th e lesion via CT guidance. Additionally, radiation therapy succeeds in relieving pain in approxim ately 50% to 80% of cases. Others have reported success with vertebroplasty in wh ich bon e cem en t is in jected in to th e vertebral body, essen tially fillin g th e lesion . Because of th e risk of h em orrh age, surgery sh ould be reserved for cases of pathologic fracture an d/ or neurologic injury. Prior to surgery, em bolization of th e lesion sh ould be done to m inim ize the risk of bleedin g.

Giant Cell Tumor Gian t cell tum or is occasion ally seen in th e spin e an d typically in volves young adults. It is the second m ost com m on ben ign n eoplasm of th e spin e occurrin g in th e sacrum th e vast m ajority of th e tim e. Usually arising in the vertebral body, exten sive destruction an d expan sion of th e bon e m ay be seen . As with m ost oth er vertebral tum ors, pain is th e m ost com m on presen ting complaint, followed by n eurologic impairm ent. MRI is vital in dem onstrating the extent of disease an d in h elpin g guide surgical treatm en t. Because of th e aggressive n ature of th ese lesion s, surgical treatm en t involves wide excision with reconstruction. Despite aggressive treatm ent, recurrence is com m on with a rate between 10% an d 50%.

Primary Malignant Neoplasms of the Spine Multiple Myeloma, Plasmacytoma, and Lymphoma Hem atogenous m align an cies of th e spin e include m ultiple myelom a, plasm acytom a, and lymphom a. Multiple myelom a an d plasm acytom a represen t two en ds of a spectrum of B-cell lymphoproliferative diseases. Solitary plasm acytom a involves an isolated lesion that com m on ly occurs in the spine, whereas in m ultiple myelom a, as the nam e implies, the disease is dissem in ated and the prognosis bleak. Anem ia is com m on with m ultiple myelom a,

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an d th e presen ce of an osteopen ic compression fracture in a patien t wh o is an em ic sh ould alert th e physician to th e possibility of myelom a. Alth ough plasm acytom a is con sidered a precursor to dissem in ated m yelom a, th e n atural h istory is sign ifican tly better; McLain an d Wein stein reported a 5-year survival rate of 60% with solitary plasm acytom a of th e spin e, wh ereas th e 5-year survival rate in patien ts with m ultiple myelom a was only 18%. Both diseases occur equally in m en an d wom en presen tin g m ost com m on ly between th e sixth an d eigh th decades. Diagn osis can gen erally be suspected by radiograph s sh owin g lytic lesion s in the case of m ultiple myelom a or a solitary lesion in the case of plasm acytom a. Con firm ation occurs with a m on oclon al gam m opathy on serum an d urin e electroph oresis. Local treatm en t of th ese lesion s con sists of radiation in m ost cases. The exquisite radiosen sitivity of this condition usually ren ders operative treatm en t un n ecessary, an d surgery is reserved for path ologic fractures with spin al in stability or n eurologic deficit th at worsen s despite radiation . Mild or m oderate degrees of cord com prom ise due to soft-tissue spread of myelom a can usually be treated with radiation. Lym ph om a, eith er prim ary or m etastatic, can occur as an isolated spin al lesion . Approxim ately 10% of cases of lym ph om a of bon e, eith er prim ary or secon dary, in volve th e spin e with predilection for th e th oracic spin e. Local treatm en t consists of radiotherapy with adjuvant ch em oth erapy if m ultifocal disease is presen t. Surgery is reserved for cases of path ologic fracture with in stability or n eurologic com prom ise n ot respon din g to radiation therapy.

Osteosarcoma Th e spin e is a rare site for prim ary osteogen ic sarcom a (on ly 3% of all prim ary osteosarcom as), an d th e treatm en t of osteosarcom a in th is location represen ts a particularly ch allenging un dertaking with a poor prognosis. Most patients presen t with pain , alth ough n eurologic deficits are presen t over 50% of th e tim e as well. Most cases arise in th e vertebral body, usually with exten sive soft-tissue m asses or extra-com partm en tal disease at th e tim e of diagn osis. A variety of radiograph ic appearan ces m ay be seen from blastic to lytic or a com bination, both generally involvin g cortical destruction . CT is useful to sh ow th e path ologic bony anatomy, while MRI is useful in delineatin g the soft-tissue path ology. Alth ough progn osis is poor, an aggressive attempt at ch em oth erapy prior to en bloc excision an d recon struction followed by adjuvan t radioth erapy is gen erally recom m ended. Ewing’s Sarcoma As with osteosarcom a, Ewin g’s sarcom a rarely presen ts in th e spin e, accoun tin g for approxim ately 5% of all cases. It also has a predilection for the vertebral body and is m ost com m on in th e sacrum (50% of th e tim e). Again , patien ts presen t m ost com m on ly with pain , alth ough n eurologic

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deficits are com m on with Ewin g’s sarcom a. Secon dary softtissue exten sion is typical, an d it is com m on ly presen t at th e tim e of diagn osis. Th ese tum ors are gen erally lytic in n ature with eviden ce of soft-tissue exten sion on MRI. Diagn osis is gen erally not m ade until after biopsy showin g sm all roun d blue cells. Th e radiosen sitivity of Ewin g’s sarcom a m akes h igh -dose radioth erapy with adjuvan t ch em oth erapy th e treatm en t of ch oice for m ost lesion s. Surgery is un dertaken for path ologic fracture with in stability or n eurologic comprom ise. Alth ough better th an for osteosarcom a, the prognosis for patients with Ewing’s sarcom a of the spine is worse th an for extrem ity disease, an d 5-year survival rates are aroun d 30% with proper treatm en t.

Chordoma Ch ordom a is a slow growin g m align an cy arisin g from th e residual n otoch ord in th e m idlin e of th e spin e an d skull base. Th ese tum ors are m ost com m on in th e sacrum an d

A

th e clivus (skull base) but can occasion ally be seen in th e lum bar, thoracic, and cervical spin e as well. It is twice as com m on in m en compared with wom en an d com m on ly presen ts between th e fifth an d seven th decades of life. Secon dary to its in dolen t n ature, sym ptom s develop slowly, and patients frequently have a large paraspinal or presacral m ass presen t at th e tim e of diagn osis. Many tim es, the m ass m ay be palpated on exam ination through the rectum . Radiographs typically show a lytic lesion with variable am ounts of calcification. MRI is the im aging of choice to evaluate these lesions as there is usually a significant soft-tissue com pon en t at the tim e of diagnosis (Fig. 12.31). Th ough th e tum or is slow growin g, h igh recurren ce rates are seen without wide surgical excision. True cure of the patient with chordom a is rare, but long-term survival can be achieved with local disease con trol. Aggressive surgical excision sh ould be un dertaken , even if sacrifice of sacral n erve roots is th e price; fun ction al disability related to sacral n erve

B

Figure 12.31 L2 chordoma with extension

C

one level above and one level below. (A) Sagittal MRI shows epidural extension into adjacent bodies. (B) Axial MRI shows canal compromise. (C) CT scan showing bone destruction. (Reproduced with permission from Frymoyer JW, Wiesel SW, An HS, et al. The Adult and Pediatric Spine, 3rd ed. Philadelphia: Lippincott Williams & Wilkins, 2003.)


root resection h as been acceptable in m ost series wh en compared with th e prospect of disease control.

Metastatic Disease of the Spine Th e overwh elm in g m ajority of spin al tum ors represen t m etastatic lesions, particularly in patients over the age of 40. A h istory of persisten t back pain , un relieved by rest, particularly in a patien t with a kn own h istory of can cer should alert the physician about the possibility of a m etastatic deposit in th e spine. Prim ary m alignan cies that m ost com m only m etastasize to the spin e include breast, lung, prostate, kidney, an d thyroid cancers. Advances in supportive care for patien ts with these and oth er types of m alignancies as well as advances in awaren ess, im aging, an d surgical techn ique have greatly increased the n um ber of patien ts presen tin g for surgical treatm en t of m etastatic disease of th e spin e. Th e spin e is th e th ird m ost com m on site for m etastasis in th e body, and sym ptom atic spinal m etastasis are th e presen tin g com plain t in approxim ately 15% of n ew can cer diagn osis. Approxim ately 90% of m etastatic deposits in th e spine originate in the vertebral body wh ere the trabecular bon e acts as a filter to blood-born e m etastases (Fig. 12.32). It is hypoth esized th at th e red m arrow of th e trabecular bon e of th e vertebra provides a favorable en viron m en t for deposition an d proliferation of tum or. O n ce deposited,

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tum or cells are capable of form in g a protective fibrin sh eath an d of secretin g osteoclast activatin g factors an d possibly lytic prostaglan din s, wh ich furth ers th eir spread. Patien ts presen t prim arily with pain , wh ich accordin g to Harrin gton , m ay be due to cortical expan sion with m icrofracturin g an d in vasion of paravertebral soft tissues, compression of adjacen t n erve roots, path ologic fracture with in stability, or com pression of th e cord. Th e h istory of back pain in a patien t with a prior diagn osis of can cer sh ould be viewed as worrisom e, even with a rem ote h istory of a m align an cy presum ed to be cured; th is is particularly true for carcin om a of th e breast. Th e diagn osis of m etastatic disease of th e spin e is m ade radiographically and confirm ed by the pathologist. Plain film s are relatively in sen sitive because of th e exten t of vertebral body destruction th at is n ecessary before a radiographic abnorm ality is seen (50%). The test of choice is MRI, alth ough bon e scan is sen sitive, but n on specific, for m etastatic lesion s. MRI dem on strates early lesion s, accurately defines soft-tissue spread, im ages neural compression , an d is very specific in differentiating m etastatic disease from in fection . On e com m on quan dary for wh ich MRI is th e m ost h elpful n on in vasive m odality is differen tiatin g a path ologic fracture caused by osteopen ia from m etastatic disease. In our experien ce, m ost path ologic fractures caused by m etastatic deposits display a pattern of diffuse m arrow replacem ent, have involvem ent at m ore than

A

B Figure 12.32 Metastatic disease. (A) Sagittal MRI scan of a 58-year-old man with isolated colon

adenocarcinoma metastasis to L5 with low-back pain. (B) Sagittal CT reconstruction showing mixed blastic and lytic regions within L5. (Reproduced with permission from Frymoyer JW, Wiesel SW, An HS, et al. The Adult and Pediatric Spine, 3rd ed. Philadelphia: Lippincott Williams & Wilkins, 2003.)

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on e level, or h ave an associated paraspin al soft tissue m ass. Fin ally, CT scan can be very h elpful as well, especially wh en evaluatin g th e am oun t of bony destruction by th e lesion . O n ce all im agin g th at is n ecessary h as been com pleted, CTguided biopsy is th e test of ch oice in alm ost all cases for accurately establish in g th e diagn osis before proceedin g to treatm en t. Treatm en t of m etastatic disease of th e spin e m ay be system ic, local, or both . System ic treatm en t con sists usually of ch em oth erapy, as appropriate for th e in volved tum or. Because of th e complexity of treatm ent for m ost of these cancers, the treatm ent should involve a m ultidisciplinary team in cludin g a m edical on cologist, a radiation on cologist, orthopedic on cologist, and/ or orthopedic spine surgeon fam iliar with treatin g spin al tum ors. Patien ts wh ose disease is am en able to ch em oth erapy alon e rarely com e un der th e treatm en t of an orth opedic surgeon , but ch em oth erapy as the prim ary m ode of treatm ent should be con sidered for can cers such as prostate or breast in wh ich m etastatic deposit is seen with out collapse or n eurologic com prom ise, as well as for certain h em atopoietic m align an cies. Local treatm en t m ay con sist of radioth erapy, bracin g, or surgery. Radioth erapy is th e treatm en t of ch oice for the large m ajority of m etastatic lesions of the spine. The efficacy of radioth erapy is h igh ly depen den t upon th e radiosen sitivity of the tum or present. The m ost radiosensitive tum ors, such as myelom a, lymph om a, Ewin g’s sarcom a, and to a lesser extent carcinom a of th e breast, respond high ly favorably to radiotherapy, which should be considered in virtually all such cases unless clear-cut spinal in stability is presen t. O n th e oth er h an d, radioresistan t lesion s such as carcinom a of the lun g or prostate, GI can cers, or renal cell carcin om a have a m uch less favorable response an d surgery should be un dertaken in these diseases if th ere is vertebral collapse with pain , borderlin e in stability, or impen din g n eurologic comprom ise. O bviously, th is relatively aggressive surgical approach would be tempered by th e overall extent of patient disease, associated m edical problem s, and the presence of m ultiple levels of spinal in volvem en t. Bracing m ay be used as an adjunct to radiotherapy. Custom -m olded th oracolum bosacral or lum bosacral orthoses frequently provide excellent short-term pain relief an d m ay be particularly advan tageous in patien ts with lim ited life expectan cy. Halo-vest im m obilization sh ould be considered in patients with radiosensitive m etastatic lesion s in the cervical spin e where sh ort-term prophylaxis again st n eurologic catastroph e is n eeded, pen din g disease ablation with eith er radioth erapy or ch em oth erapy. Another m ean s of treating pain from compression fractures secon dary to m etastatic lesion s is th rough vertebroplasty or kyph oplasty in wh ich cem en t is in jected in to th e vertebral body providin g stability an d preven tin g furth er collapse. Kyph oplasty involves insufflations of the vertebral segm en t prior to PMMA in jection an d th eoretically

results in greater correction of collapse in comparison to vertebroplasty. It m ust be n oted th at these are symptom atic treatm ents on ly but offer a m inim ally invasive alternative for m any patients th at are not suitable for larger surgical procedures. Curren tly, th is is an off-label use for vertebroplasty/ kyph oplasty, but th ese procedures do provide patients with significant pain relief. Th e fin al m eth od of local treatm en t is surgery. Th e in dication s for surgical in terven tion in m etastatic disease of th e spin e in clude (1) th e n eed for tissue for diagn osis; (2) a radioresistan t tum or with local collapse or im pen din g n eurologic impairm en t; (3) persisten t or recurren t pain or n eurologic deficit despite radioth erapy; (4) n eurologic deterioration durin g radioth erapy; (5) n eurologic deficit due to bon e or disk retropulsion ; an d (6) spin al in stability, eith er presen t or impen din g. All but item 6 are relatively straigh tforward. The definition of spinal instability in m etastatic disease is th e source of sign ifican t debate. We feel th at lesion s th at result in greater than 50% collapse of the vertebral body, particularly at th e th oracolum bar jun ction , any translation al deform ity on either AP or lateral radiographs, segm en tal kyphosis of greater than 20 degrees above that expected at th e in volved level, an d lesion s th at in volve both th e an terior an d posterior colum n s sh ould be con sidered poten tially un stable. A h igh ly radiosen sitive tum or fulfilling one of those criteria is occasionally treated first with radioth erapy, but surgery perform ed before radioth erapy is m ore likely to preserve neurologic function, relieve pain, and preserve overall function while m inim izing the risk of operatin g th rough previously radiated tissue. Th e surgical approach for m etastatic lesion s can be an terior, posterior, or com bin ed. Because m ost m etastatic lesion s arise anteriorly an d result in destruction of the anterior colum n of th e spin e, with an terior cord or cauda equin a com pression , our preferred approach is usually an terior. Th is approach allows safe an d th orough decompression of th e spin al can al as well as m ech an ically soun d recon struction of the an terior colum n of the spine. There are m ultiple form s of in strum entation and stabilizin g devices that can be used such th at th e an terior approach alon e can be used in the m ajority of situations. Alternatively, the posterior approach or posterolateral approach can be used. Lam inectomy alone is relatively inefficien t at decom pressin g th e spin al can al an d sh ould be avoided in m ost cases. However, posterolateral decom pression h as been used with success with results comparable with th e an terior approach . Fin ally, depen din g on th e stability n eeded or th e am oun t of decom pression n eeded, th ese procedures can be com bin ed with th e down side of a m uch larger surgery with greater m orbidity. Overall, aggressive surgical treatm en t h as gained widespread acceptan ce for th e treatm en t of m etastatic spin al disease in patients th at fit the criteria outlin ed. This reflects our experien ce th at, in th e properly selected patient, surgical treatm ent of m etastatic disease of the spin e


is highly predictable for pain relief, restoration an d protection of n eurologic function, and an acceptably low complication rate.

SPINE INFECTIONS In fection s of th e spin e occupy a perversely importan t place in the history of orthopedic surgery in general and spine surgery in particular. Percival Pott’s description of tuberculosis (TB) and associated paralysis gave rise to the endurin g eponym “Pott’s paraplegia.’’ Many of th is cen tury’s sem in al advances in spin e surgery including the developm en t of posterior fusion of the spine by Hibbs and Albee related to th e treatm en t of tuberculous spon dylitis. Hodgson pioneered an terior surgery of th e spine, curren tly in widespread use for n um erous con dition s, as th e treatm en t for spinal TB. We now see infections of the spine in num erous settings and caused by a variety of organism s, but despite sign ifican t tech n ologic an d m edical advan ces in our treatm ent, the underlyin g prin ciples of the treatm en t of infection of the spine are still largely based on lesson s learned from TB.

Pyogenic Infection Th e in ciden ce of pyogen ic vertebral osteomyelitis appears to be in creasin g with an in crease in m edical an d social con dition s th at lead to im m un osuppression . Th e spin e is th e site for up to 7% of all cases of osteomyelitis and certainly is the area with the greatest poten tial for m orbidity. Prior to the current an tibiotic era, the m ortality secondary to vertebral osteomyelitis reach ed 20% to 25%. With th e adven t of curren t an tibiotic treatm en t an d advan ces in spin al surgical techniques, the m ortality rate is less than 10%, with a significant drop in m orbidity as well, but the consequences can still be devastating. Th e path ophysiology of vertebral osteomyelitis arises from three potential sources: direct in oculation, con tiguous spread from an oth er source, an d th e m ost com m on , hem atogenous spread. Direct in oculation can occur via pen etratin g traum a or from iatrogen ic in oculation th rough procedures ran gin g from surgical in terven tion to percutaneous procedures. Con tiguous spread as the n am e implies occurs from an oth er in fection in th e region of th e affected area, generally a retroperitoneal abscess or possibly from the spinal canal itself. The vast m ajority of cases are th e result of h em atogen ous spread from a distan t source, with the m ost com m on locations being the genitourin ary tract, the skin and soft tissues, and the upper respiratory tract. Approxim ately 50% of patients with an in fection of the spine will give a h istory of a preceding in fection elsewh ere. Th e in fection seeds th e m etaphyseal region of th e vertebral body th rough th e rich an astom otic n etwork in th e area. Once the infection reaches the vertebral body, it locally

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spreads an d com m on ly violates the vertebral end plate to in volve th e avascular in tervertebral disk, wh ich com m on ly distin guish es in fection from m etastases on plain film an d MRI. Because of th e avascularity of th e disk, bacteria th rive in th is region an d quickly degrade th e disk, allowin g en tran ce in to th e adjacen t vertebral body. In stability often en sues secon dary to degradation of th e disk an d th e vertebral body. Th e in fection can th en furth er spread to adjacen t vertebrae or in to th e soft tissues in cludin g th e prevertebral fascia in the neck and retroperitoneal structures such as the psoas m uscle in the lum bar region . If left untreated, even tually, patien ts can develop n eurologic com prom ise secon dary to instability and collapse with subsequent im pin gem en t of n eural structures, path ologic fractures, or direct impin gem en t from th e in fection itself in th e form of an epidural abscess. Death can subsequen tly en sue from n eurologic com prom ise, alth ough m ost com m on ly results from septicem ia. Alth ough in fection of th e spin e m ay occur in any age group, there appears to be two peaks: ch ildren /adolescents an d patien ts greater th an 50 years of age. Th is article will focus on infection s in the adult population, but as an aside, the pediatric population gen erally is affected by bloodborn e diskitis secon dary to th eir un ique blood supply to the vertebral region. In adults, m ost, but not all, cases of vertebral osteomyelitis occur in im m un osuppressed patien ts an d th e elderly, with m ales bein g m ore com m on ly affected than fem ales. Im m unosuppressive disorders such as RA an d diabetes, th e use of im m un osuppressive m edication following surgery, im m unosuppressive states such as AIDS, an d a h istory of IV drug abuse are all frequen tly associated with spine in fection . Th e causative organ ism s seen in m ost in fection s of th e spin e h ave evolved over tim e. In th e pre-an tibiotic era, Staphylococcus aureus predom in ated. More recen tly, th e in ciden ce of S. aureus h as dropped sign ifican tly, alth ough th e in ciden ce of m eth icillin -resistan t S. aureus is on the rise. Th ey both still accoun t for approxim ately 50% of infection s. Gram -n egative in fection s are in creasin g in n um ber, likely from th e in creasin g rate of pseudom on as in fection in IV drug users, alth ough th ese are th e usual organ ism s from genitourinary tract in fections as well. Not uncom m on are in dolen t in fection s caused by low virulen ce organ ism s such as Staphylococcus epidermidis an d Streptococcus species. Fin ally, an aerobic organ ism s can also be foun d particularly in diabetic patien ts. Th e prim ary m an ifestation s of pyogen ic in fection of th e spin e in clude pain , n eurologic impairm ent, an d signs and symptom s of sepsis, with the m ost com m on complaint bein g pain . Carragee et al. reviewed a large series of patien ts with pyogen ic in fections and foun d that over 90% presen ted with pain. A h istory of pain at night should alert the physician to a condition m ore serious than run of the m ill back pain . A n um ber of auth ors h ave dem on strated the tendency toward delay in diagnosis; as m any as 50%

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of patien ts h ave pain for 3 m on th s or lon ger prior to th e correct diagnosis of spin al sepsis. Greater awareness and improved im agin g tech n iques appear to be lessen in g th is problem . Fever is less com m on th an pain an d is seen on ly in about 50% of patien ts. Fifteen to 20% of patien ts will presen t with eviden ce of n eurologic in volvem en t, with predisposin g factors in cludin g diabetes, RA, in creasin g age, an d a m ore ceph alad level of in volvem en t. Fin ally, approxim ately 15% of patien ts will presen t with atypical symptom s such as hip pain, abdom in al or chest pain, or testicular discom fort. These atypical complaints are m ore com m on in in fection s in th e lum bar spin e an d con tribute sign ifican tly to prolon ged delay in diagn osis. The im portan ce of recognizing the patient at risk for spin al in fection as well as recognizin g th e com m on presen ting complaint is highligh ted by th e paucity of specific physical fin din gs suggestin g in fection . Abscesses are n ow quite rare but are seen m ore com m on ly in in fection s of the cervical or th oracic spine. Significant paraspinal spasm m ay be seen , an d pain on percussion in th e m idlin e, at the affected level, is the m ost specific finding. An infection with a subsequen t psoas abscess will have pain with h ip exten sion . Oth er physical fin din gs can relate to n eurologic fin din gs, but n o physical exam in ation m an euvers are particularly specific for in fection . Laboratory studies are a very im portan t aspect for th e workup of possible in fection , especially wh en con siderin g the lack of specificity of the physical exam ination, alth ough laboratory values m ay even furth er con fuse th e clin ical picture. Awh ite blood cell (WBC) coun t, eryth rocyte sedim en tation rate (ESR), an d C-reactive protein (CRP) sh ould be obtain ed in all patien ts suspected of h avin g an in fection . Th e m ost sen sitive test of all of th ese is th e ESR th at is elevated over 90% of th e tim e, with th e CRP bein g th e next m ost sen sitive. Both of these tests are n onspecific but sh ould not be elevated in a patient with nonspecific back pain , an d th erefore, furth er studies are warran ted sh ould on e or both of th ese be elevated. Th e WBC coun t, on th e oth er h an d, is on ly elevated approxim ately 50% of th e tim e an d is th erefore less useful. O n ce an in fection h as been diagn osed, treatm en t respon se can be followed by m on itorin g th e CRP, wh ich drops m uch m ore quickly th an th e ESR. Fin ally, blood cultures sh ould be obtain ed. Radiographic evaluation is vital in cases of infection and sh ould begin with plain film s. Un fortun ately, plain film s are relatively in sen sitive in early in fection s of th e spin e, an d n orm al routin e x-rays of th e back are of lim ited value in rulin g out in fection . Th e m ost com m on early fin din g, frequently seen only retrospectively, is soft-tissue swelling in cludin g loss of th e psoas sh adow or widen in g of th e retroph aryn geal clear space in th e n eck. Th ree to 4 weeks following the establishm ent of infection, disk space narrowin g m ay be seen . Alth ough disk space n arrowin g can be due to a n um ber of causes, irregularity an d destruction of th e bony en d plate are n ot presen t in degen erative disorders of th e spin e an d sh ould h eigh ten suspicion of in fec-

tion. Fin ally, at about 6 weeks, destructive changes in the vertebral body, including collapse and lysis anteriorly, are seen . Much m ore sen sitive th an plain film s, scin tigraphy offers an excellent m ethod of detecting early spin al infection. The m ost sen sitive and frequently used m ethod is tech n etium -99 m bon e scan with sen sitivities greater th an 90%, th ough specificity is low. However, it rem ain s very useful especially as a screen in g test wh en in fection is suspected an d plain film s are n egative. Oth er m eth ods in clude gallium scann ing and in dium -111-labeled leukocyte scann ing, both of wh ich are less sen sitive, with leukocyte scan n ing th e least sensitive. Prior to th e em ergen ce of MRI, gallium scann ing was often com bined with technetium scann in g to im prove both th e sensitivity and specificity, and this com bination can still be used but rarely needs to be. Th e im agin g m odality of ch oice is MRI. MRI h as a sen sitivity greater th an scin tigraphy (around 95%) an d m uch h igher specificity (greater th an 90%), wh ile addition ally providin g detailed im agin g of th e exten t of path ologic in volvem en t and the specific structures involved. Because a positive or even equivocal bon e scan will alm ost always lead to ordering an MRI, our practice is to utilize th is test initially when in fection of the spine is suspected. A ch aracteristic MRI picture is seen in vertebral osteomyelitis (Fig. 12.33). We rely m ost h eavily on th e T2weigh ted im ages, wh erein in creased sign al is seen in th e disk space as well as in volved areas of th e vertebral bodies. Th is is m ore striking following the adm inistration of gadolinium , which should be ordered with th e study when infection is suspected. Th e m ost sign ifican t findin g is the increased signal in the disk space, wh ich clearly differentiates infection from degenerative change. MRI distinctly defines disk and end plate destruction, enabling distinction between in fection an d tum or of th e spin e. Neoplasm s, as previously explain ed, do n ot in volve th e disk space wh ile infections do. Fin ally, CT scan n in g is n ot typically used in th e in itial evaluation for in fection . However, m any tim es CT can be very helpful in preoperative planning to better define the am ount of bony destruction. Before treatm en t is in itiated, laboratory con firm ation of th e presen ce of in fection an d th e causative organ ism sh ould be sought. Con firm ation by a positive culture from th e spin e or blood is preferable to begin n in g em piric an tibiotic therapy unless system ic sepsis is present. Biopsy of th e spin e can usually be perform ed via a percutan eous approach. Fluoroscopy and, when needed, CT guidan ce allow for m inim ally invasive access to the en tire spine an d h ave been reported to lead to accurate diagn osis in 68% to 86% of cases of vertebral osteomyelitis. When initial percutan eous aspiration does n ot result in positive culture or histopathologic findings, the decision m ust then be m ade about th e n ext step in evaluation an d treatm en t. In our practice, on ly rarely is empiric m edical m an agem en t


A

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B Figure 12.33 Vertebral osteomyelitis. A 78-year-old male on hemodialysis presented with back

pain, fevers, and progressive paraplegia, though incomplete. (A) Sagittal T1 gadolinium MRI demonstrating enhanced signal within T7 and part of T8 and an anterior epidural mass compressing the cord. (B) Sagittal reconstruction CT scan shows advanced destruction of T7 and part of T8. Sclerotic changes in the infected vertebrae are noted. (Reproduced with permission from Frymoyer JW, Wiesel SW, An HS, et al. The Adult and Pediatric Spine, 3rd ed. Philadelphia: Lippincott Williams & Wilkins, 2003.)

un dertaken at th is stage. We fin d it h elpful to con sult with our in terven tion al radiologists to see if th ey believe th at an oth er attempt at biopsy is likely to be m ore rewarding; if not, we typically proceed with open biopsy and defin itive debridem en t. Treatm en t of pyogen ic vertebral osteom yelitis can be m edical or surgical, but, regardless of the m eth od, the goals rem ain th e sam e. Th e goals of treatm en t are iden tification of th e path ogen , eradication of th e path ogen , an d m ain ten an ce of stability an d n eurologic fun ction . Th e type an d duration of m edical treatm en t are dictated by th e causative organ ism cultured. Because of th e con tin uous evolution in available an tibiotics, we routinely utilize infectious disease con sultation to select th e agen t used. It should be noted th at ceph alosporin penetration into the nucleus pulposus is less effective th an th at of bon e an d, in m ost cases, th e use of an am inoglycoside sh ould be considered. We favor the use of paren teral an tibiotics for 6 weeks followed by th e use of oral an tibiotics, wh en available, for an oth er 6 weeks. Wh en m edical m anagem ent of vertebral osteomyelitis is undertaken , it sh ould be appreciated th at a protracted course of treatm ent is necessary before symptom atic resolution can be expected, an d we h ave foun d th at exten din g treatm en t

for a total of 3 m onths leads to increased success. Response to treatm en t can be m on itored by respon se of th e ESR an d CRP. Th e CRP is a better in dicator as a respon se can be seen in 48 to 72 h ours, wh ile th e ESR takes aroun d 1 to 2 weeks. Th e CRP can be m onitored over th e first few days following treatm en t an d th en exten din g ESR an d CRP m on itorin g to weekly checks for 3 to 4 weeks followed by m onthly testing un til a return to n orm al is seen . Medical treatm ent of spinal in fections is accompan ied by im m obilization. The hospitalized patient is usually placed on bed rest for several days an d th en m obilized, as symptom s allow, in a custom -m olded or custom -m ade orth osis. Am bulatory patien ts diagn osed in th e outpatien t setting, n ow seen with in creasing frequency, are not placed on bed rest but are placed in to a custom -m olded TLSO or a cervical orth osis depen din g on th e level of in volvem en t. Th e in dication s for surgery in clude th e n eed for tissue for diagn osis, th e presence of significant destruction or deform ity, failure of m edical m an agem en t, n eurologic deficit caused by spin al cord compression by eith er abscess, disk, or bon e, an d the presence of a clinically significan t paraspin al or epidural abscess. Each of th ese in dication s is som ewh at subjective an d open to in terpretation .

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As noted, we believe strongly in th e need for a bacteriologic diagn osis wh en ever possible, an d wh en m in im ally in vasive tech n iques fail, we prefer defin itive surgical treatm en t as a m ean s of obtain in g tissue rath er th an a lim ited open tech n ique. The extent of bony destruction or deform ity leadin g to the need for surgical treatm en t has not been clearly defin ed; it is importan t wh en evaluatin g th e patien t with a possible n eurologic deficit to recogn ize th e exten t to wh ich kyph osis can contribute to compression of th e spinal cord an d cauda equin a. Progressive kyph osis with retropulsion of disk or bon e will n ot respon d to bracin g or an tibiotics an d sh ould be promptly recogn ized an d treated surgically. Failure of m edical m anagem ent requires the correlation of a n um ber of factors. In th e patien t with m in im al an terior colum n destruction who is neurologically intact without eviden ce of abscess form ation , we favor a m in im um of 4 weeks of antibiotic treatm ent alon g with rest and bracing. At th at tim e, the absence of a significant decrease in the patien t’s pain as well as th e absen ce of a sign ifican t declin e in the ESR/ CRP would lead to consideration of either repeat biopsy to en sure th at th e proper organ ism is bein g treated, or defin itive surgical treatm en t. The significance of the radiographic appearance of abscess form ation should be m entioned. The presence of a soft-tissue m ass in th e paraspinal or epidural space is usually n ot, in our experien ce, eviden ce of pus un der pressure. Although frequently a large paraspinal or epidural m ass is presen t in a patien t with sign ifican t destruction or neurologic comprom ise, in the absen ce of these m ore con crete surgical indication s we typically prefer to undertake nonoperative m anagem ent and closely follow the patien t. Awaren ess of th e previously described risk factors for n eurologic in jury, in cludin g in creasin g age, im m un osuppression , an d involvem en t of th e cervical spin e facilitates appropriate decision m akin g in th is settin g. Vertebral osteomyelitis is prim arily a disease of the anterior colum n , an d bein g such , it is axiom atic th at surgical treatm ent should approach this disease directly from an an terior approach . Th e an terior approach to th e spin e was pioneered by Hodgson for the treatm en t of tuberculous spon dylitis an d is still favored in th e vast m ajority of cases. With the exception of lim ited posterior or posterolateral approach es for biopsy, th ere is little advan tage of an isolated posterior approach as th orough debridem en t is rarely possible an d lam in ectomy for decompression h as been dem on strated to destabilize an in fected spin e. The anterior approach lends itself ideally to th orough surgical debridem en t, decompression of the spin e or cauda equin a, an d stabilization of th e spin e. O n ce debridem en t of th e in fection is carried out, an d bleedin g bon e above an d below th e in volved area is seen , autogen ous strut graftin g has been dem onstrated to be safe and effective. As an altern ative, in recen t years, th e use of titan ium surgical m esh with autogenous bone graft has been used with success as well, though long-term follow-up is lacking.

Anterior stabilization alone followed by casting or bracing is usually sufficient for single-level involvem ent in wh ich th e kyph otic deform ity can be m ostly corrected. A com bin ed approach with posterior stabilization is gen erally reserved for cases of m ultilevel disease or cases with residual kyph osis of 20 degrees or greater. Th is m ost typically occurs in lon g-stan din g in fection s at th e th oracolum bar jun ction . Wh en posterior stabilization is un dertaken , m ost authors believe th at the risk of secondary in fection of th e orth opedic im plan ts posteriorly is acceptable, an d th is h as certainly been our experien ce. Th e improvem en t in outcom es seen followin g m edical and surgical m anagem ent of pyogenic vertebral osteomyelitis is striking. Nonoperative treatm en t is successful in the m ajority of patients particularly in those that are not im m unocomprom ised, an d surgical treatm ent has a success rate of over 90% to 95% in term s of obtain in g solid bony fusion and pain relief. In short, m odern surgical and m edical techniques have alm ost completely elim inated the risk of death , in th e absen ce of failure of oth er organ system s, lead to predictably good rates of healing of the spine with good relief of pain, and lead to predictable improvem en t in neurologic function when impaired.

Epidural Abscess Abscess form ation in the epidural space occurs alm ost exclusively in adults and, with increasing num bers of elderly an d im m unosuppressed patients, appears to be in creasing in frequen cy. Although epidural abscess can occur secon dary to spread from a focus of vertebral osteomyelitis, a distin ct en tity of epidural abscess arisin g from h em atogen ous spread from a rem ote source of in fection or from direct in oculation is also seen . It is importan t to distin guish prim ary epidural abscess from a secon dary abscess associated with vertebral osteomyelitis; prim ary in fection of the epidural space is n ot associated with destruction or in stability of th e spin e, is frequen tly seen posterior to th e cord an d cauda equina, and therefore has significantly different treatm ent implications. It is by all accounts a m edical an d surgical em ergen cy. A h igh in dex of suspicion is m an datory wh en approach ing the patient with a potential epidural abscess. The initial diagnosis is m issed in approxim ately 50% of cases, an d there are various m odes of presentation . Therefore, one m ust keep in m ind th e risk factors that are the sam e as for pyogenic infection. Symptom s m ay be short lived, of less th an 1 to 2 weeks duration, or chronic exten ding over several m on th s. Th e m ost com m on findings with acute epidural abscess are fever, back pain , an d localized ten dern ess, but on e or all of th ese m ay be absen t with a m ore ch ronic presen tation. An om inous progression of the disease h as been described. Pain in th e m idlin e of th e back or n eck persists for a variable period of tim e, followed by radicular pain , possibly weakn ess, an d fin ally paraparesis an d paralysis. The tim ing of this progression varies, and


deterioration to th e n ext n eurologic stage m ay be gradual or sudden . Diagn osis requires bacteriologic con firm ation . Laboratory fin din gs suggestive of epidural abscess in clude elevation of the ESR, which is alm ost always elevated, averaging 86.3 m m / hr in a study by Gardner. The WBC count is m ore variable (less sen sitive), at tim es with no elevation, but is generally elevated as well. In the sam e study by Gardn er, th e average WBC coun t was 22,000 cells/ m m 3 . Patien ts with m ore long-standin g disease typically h ave less dram atic leukocytosis. Th e CRP is also gen erally elevated, though less research has focused on the CRP as it is a relatively n ew laboratory value in comparison to th e ESR. Radiographic evaluation is undertaken, but plain radiograph ic fin din gs are frequen tly m in im al. Historically, myelography has been used to evaluate for epidural abscess, but as with vertebral osteomyelitis, MRI has evolved as th e im agin g m odality of ch oice. Ideally with th e addition of gadolin ium to im prove sen sitivity, MRI provides visualization of the abscess and th e extent of n eural elem en t compression while giving the added benefit of iden tifyin g concurrent vertebral osteomyelitis when present. T1 im ages typically appear hypoin ten se (m ay be isoin ten se), T2 im ages appear hyperin ten se, an d th e addition of gadolin ium often sh ows periph eral en h an cem en t typically seen with abscesses. Prompt intervention is required once an epidural abscess is diagn osed. Most auth ors con sider epidural abscess a surgical em ergen cy an d we con cur. Certain ly all patien ts, on ce a bacteriologic diagn osis is ach ieved, sh ould be started on h igh-dose IV antibiotics. Surgery is in dicated un less th e patien t is such a poor surgical can didate th at th e risks outweigh th e ben efits. Th ere are som e advocates for in itial n on operative m an agem en t for th ose patien ts wh o are n eurologically intact, though this is controversial. Unlike epidural abscess secondary to vertebral osteomyelitis, prim ary epidural abscess is routin ely treated surgically by lam inectomy. Spinal stability can usually be preserved wh ile still th orough ly un roofin g an d debridin g the epidural space. It is imperative to prove intraoperatively that the cephalocaudad exten t of decompression is adequate. Aggressive m edical and surgical m anagem ent of epidural abscesses has radically improved the historically bleak results of treatm en t. Perioperative death is exceedin gly rare, an d depen din g on th e exten t of n eurologic deficit, sign ifican t improvem en t is frequently seen . Poor prognostic factors in clude den se or lon g-stan din g n eurologic deficit, diabetes, an d advan ced age.

Tuberculosis of the Spine TB an d tuberculous spon dylitis are both diseases th at h ave a h istorical sign ifican ce an d are still very com m on in developing countries. However, in industrialized countries, they are not n early as widespread as th ey once were, but

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they are still present. In 1980s and 1990s, the frequency of TB in th e Western World was on th e rise secon dary to ch ron ic im m un osuppressive disorders, m ain ly HIV, but it h as subsequen tly been on th e declin e again in recen t years. Although it is not as prevalen t in our society as it once was, a basic un derstan ding of th e disease process an d treatm ent in som uch as it relates to th e spin e is n ecessary for all orthopedic surgeons. In th e Un ited States, TB is prim arily a disease of adults, wh ile in Asia and Africa significant num bers of children are affected. Approxim ately 5% of patien ts with TBdevelop it in the spine with a neurologic deficit reported in 10% to 45% of th ese patien ts. Th e possibility of tuberculous spon dylitis sh ould be con sidered in any individual with persistent un explain ed back pain , particularly in patien ts wh o h ave em igrated from or recen tly traveled to un derdeveloped areas of th e world, or patien ts with ch ron ic im m un osuppressive disorders such as IV drug abuse or HIV in fection . Tuberculous spondylitis usually develops from h em atogen ous spread, m ost com m on ly from the pulm on ary system . In itial in oculation of th e spon giosa of th e vertebral body leads to local spread of th e disease. Th is spread h as been described in several patterns including peridiscal, cen tral, an d an terior. Peridiscal spread in volves in fection of on e vertebral body exten din g out of th e an terior cortex and under th e ALL to involve the adjacent body. A distinguish ing ch aracteristic of tuberculous spondylitis is th e relative resistan ce of th e disk to in fection , un like pyogen ic vertebral osteom yelitis. Cen tral an d an terior spread occur m uch less com m on ly th an peridiscal. Central in volvem en t occurs with sign ifican t destruction of th e vertebral body with out exten sion an teriorly or in to eith er disk space, giving th e appearan ce of m etastasis. Anterior “skip’’ lesion s m ay also be seen wh ere spread un dern eath th e ALL extends over several segm ents, seen radiographically as an terior scallopin g. Patien ts typically presen t with back pain , weigh t loss, an d in term itten t fevers. On physical exam in ation , on e sees m uscle spasm , local ten dern ess, an d restricted ran ge of m otion , th ough kyph osis, abscess form ation , an d drain in g sin uses can be seen in severe cases. Neurologic in volvem en t is m ore com m on with m ore ceph alad levels an d occurs anywh ere from 10% to 45% of th e tim e. Patien ts gen erally h ave been previously diagn osed with TB, though spinal involvem en t can be th e presen tin g symptom th at leads to th e diagn osis. Typically, th e PPD will be positive, th ough it can be n egative. With tuberculous spon dylitis, laboratory values typically show an extrem ely elevated ESR (typically over 100 m m / m in ), with a variable in crease in WBC coun t. O n ce suspected, a system ic workup for TB sh ould be undertaken. Concerning the spine, plain film s are gathered followed by MRI, the im agin g m odality of choice. Th e earliest findin g on plain film is vertebral body osteopen ia, wh ile th e disk space is preserved. MRI fin din gs m irror th e previously described path ologic picture, an d th e differen ces between

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B

A Figure 12.34 Tuberculosis of the spine. (A) Sagittal T2 MRI scan demonstrates involvement of

upper thoracic vertebral body with soft-tissue mass extending anteriorly and posteriorly into the spinal canal, causing cord compression. Note relative preservation of disks at this stage of disease, which is frequently the case with tuberculous versus pyogenic spondylitis. (B) T1 axial MRI of same patient shows extensive soft-tissue mass in the left foraminal and extraforaminal regions. (Reproduced with permission from Frymoyer JW, Wiesel SW, An HS, et al. The Adult and Pediatric Spine, 3rd ed. Philadelphia: Lippincott Williams & Wilkins, 2003.)

pyogen ic an d tuberculous in fection on MRI (Fig. 12.34) will reflect the poten tial for exten sive bony destruction before significant disk in volvem en t, m ultilevel spread under the ALL, or central in volvem en t m im icking tum or. Addition ally, tuberculous spon dylitis is m ore likely to result in exten sive abscess form ation , eith er in th e paraspin al region or in th e psoas. The treatm ent for spinal TB has evolved over th e years an d h as m ade sign ifican t strides with m edical m an agem en t sufficin g in m ost cases. We favor a 9-m on th course of m edical m an agem en t for th e m ajority of cases con sistin g of a four-drug com bin ation , per recen t CDC recom m en dation s, of ison iazid, rifam pin , pyrazin am ide, eth am butol, an d streptomycin with ison iazid an d rifampin always taken th rough out th e en tire treatm en t period. Surgery is reserved for patien ts with a n eurologic deficit wh o h ave failed to respon d to 3 m on th s of n on operative th erapy as m edical m an agem en t h as proven to be ben eficial even in the face of neurologic involvem ent. The details of surgical in terven tion are beyon d th e scope of th is article, but an an terior approach is typically utilized followed by radical debridem en t of in fected bon e an d soft tissue an d debride-

m ent of any abscesses. Following adequate debridem ent, recon struction of th e spin e is un dertaken , typically with strut graftin g an d im m obilization following surgery in a fiberglass body jacket to protect the strut. With m ultilevel involvem ent or the potential for instability, posterior stabilization is perform ed as well. Outcom es have improved sign ifican tly over th e past 30 years with m odern m edical an d m odern surgical tech n iques. Prognosis for th ese patien ts is n ow good. Th e m ortality followin g surgery is on ly approxim ately 5%, wh ich is sign ifican tly decreased from th e 30%, wh ich it was not too long ago.

CONCLUSIONS Disorders of th e spin e en com pass a wide spectrum from m inor problem s such as neck strain to disabling conditions such as severe degen erative spinal stenosis. Most conditions can be treated successfully with conservative m anagem en t followin g the algorithm s outlined in the article. The success of treatm ent revolves around a good doctor–patien t


relation sh ip cen tered on patien t education an d in form ed decision m akin g. Wh en operative in terven tion is n ecessary, fairly predictable results can be obtain ed wh en surgery is perform ed for th e proper in dication s an d wh en patien ts are well in form ed about th e realistic goals an d risks of surgery. Wh ile m uch progress h as been ach ieved in th e realm of spine surgery over th e past 20 years, newer techn ologies such as disk replacem en ts m ay contin ue to im prove operative results in th e years to com e.

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RECOMMENDED READINGS Cousin s JP, Haughton VM. Magnetic reson an ce im aging of the spine. J Am Acad Orthop Surg. 2009;17:22 –30. Daniels AH, et al. Adverse events associated with anterior cervical spine surgery. J Am Acad Orthop Surg. 2008;16:729 –738. Heck AH, et al. Ven ous th rom boem bolism in spine surgery. J Am Acad Orthop Surg. 2008;16:656 –664. Reilly CW. Pediatric spin e traum a. J Bone Joint Surg. 2007;89:98 –107. Rih n JA, et al. Th e use of bon e m orph ogen ic protein in lum bar spin e surgery. J Bone Joint Surg. 2008;90:2014 –2025.

13

The Shoulder Bren t B. W iesel

Ben jam in Shaf fer

Gerald R. W illiam s

Th e prim ary purpose of th e sh oulder is to position th e upper extrem ity in space an d provide a stable platform for hand and elbow function . It is also th e m ajor power generator of th e upper extrem ity. O ften th ough t of as a sin gle joint, it is m ore appropriately described as the shoulder complex, con sistin g of m ultiple bon es, articulation s, an d m uscle–ten don un its. Wh en all of th ese elem en ts are working correctly, the complex is able to obtain a rem arkable ran ge of m otion (ROM) an d gen erate sign ifican t power. Unfortunately, th e com plexity of th e in teraction m akes th e sh oulder complex susceptible to a n um ber to traum atic an d atraum atic conditions that can lead to dysfunction and pain . Several of th ese con dition s h ave quite sim ilar presen tation s, an d a th orough un derstan din g of each disorder is essen tial in m akin g th e correct diagn osis an d ren derin g effective treatm ent. This chapter reviews th e shoulder’s functional an atomy, outlines a basic approach to th e evaluation of sh oulder problem s, an d describes th e evaluation an d m anagem ent of several of th e com m on pathologic conditions affectin g the shoulder complex.

FUNCTIONAL ANATOMY Th e sh oulder complex con sists of five articulation s working in synch rony to obtain a trem endous ROM. The prim ary articulation is th e glen ohum eral (GH) joint, in which the round hum eral head articulates with the oval glen oid. Th e rem ain in g articulation s are th e stern oclavicular (SC) join t, th e acrom ioclavicular (AC) join t, th e scapuloth oracic articulation , an d th e subacrom ial space (Fig. 13.1). Of these five articulations, on ly the GH, SC, and AC joints are true diarth rodial joints with a joint capsule containing syn ovial fluid separating opposing articular surfaces. Th e rem ain in g two articulation s are con tact areas between two m obile surfaces with an intervening bursa to facilitate m otion.

Wh en con siderin g m otion about th e sh oulder it is im portan t to realize th at alm ost any activity represen ts a com plex pattern of coordin ated m ovem en t at each of th e five articulation s. For example, elevation of th e arm gen erally consists of two-thirds m ovem ent at th e GH joint and onethird at th e scapulothoracic articulation, accompan ied by rotation an d tran slation at th e SC an d AC join ts. Furth erm ore, wh en path ology affects on e of th e articulation s it will often induce secondary path ology at the other articulation s. If m ovem en t at th e GH join t is lim ited by adh esive capsulitis, patien ts will often attempt to compensate by increasing m otion at the scapulothoracic articulation , leadin g to fatigue in th e m uscles respon sible for scapular m otion an d periscapular pain .

Osteology Th e clavicle is an S-sh aped bon e th at serves as a strut to m aintain th e norm al relationship of the shoulder girdle to the body (Fig. 13.2). On the m edial side, the strut is attached to the sternum and the first rib at the SC joint, wh ereas on th e lateral en d, th e clavicle articulates with th e acrom ion via the AC joint. Fractures of th e clavicle m ost com m on ly occur th rough th e m idportion , wh ich is th e th in n est an d n arrowest portion of th e bon e an d th erefore m echan ically weakest. Th e proxim al h um erus con sists of th e n early roun d h um eral h ead, which is approxim ately on e th ird to one h alf of a sph ere, an d th e greater an d lesser tuberosities (Fig. 13.3). Th e jun ction between the articular surface and th e tuberosities form s th e an atom ic n eck of th e h um erus, wh ereas th e jun ction of th e tuberosities to th e sh aft is referred to as the surgical neck. The articular surface is angled superiorly, with a neck sh aft an gle of 135 degrees (angle between th e hum eral shaft and a line drawn perpendicular to th e an atom ic n eck) an d in 30 degrees of retroversion wh en com pared to th e tran sepicon dylar axis of th e elbow. Th e

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Figure 13.1 The five articulations of the shoulder complex: (1)

glenohumeral, (2) scapulothoracic, (3) acromioclavicular, (4) sternoclavicular, and (5) subacromial. (From Chapman MW, Szabo RM, Marder RA, et al. Chapman’s orthopaedic surgery. Philadelphia, Lippincott Williams & Wilkins, 2001, with permission.)

greater tuberosity serves as th e in sertion poin t for th e th ree superior and posterior rotator cuff m uscles (supraspin atus, in fraspin atus, an d teres m in or), wh ile th e lesser tuberosity is th e in sertion for th e an terior cuff m uscle, th e subscapu-

laris. The tuberosities are separated by the bicipital groove, wh ich con tain s th e ten don of th e lon g h ead of th e biceps. Wh en con siderin g arth roplasty, wh eth er for recon struction after a four-part proxim al hum erus fracture or the sequela of arth ritis, it is im portan t to rem em ber th at th e tip of th e articular surface is 5 to 10 m m superior to the tip of the greater tuberosity. The blood supply to th e proxim al hum erus is prim arily via th e arcuate artery, wh ich is a term in al bran ch of th e an terior h um eral circum flex artery (Fig. 13.4). Th is vessel can be disrupted followin g proxim al hum erus fractures, leadin g to avascular necrosis. Th e th ird bon e of th e sh oulder girdle is th e scapula, wh ich h as two prim ary purposes (Fig. 13.5). First, th e scapula is th e attachm en t site for the m ajority of m uscles in volved in sh oulder m otion (Table 13.1). Secon d, th e bon e provides a m obile base for th e glen oid portion of th e GH articulation . In addition to th e glen oid, th e lateral aspect of th e scapula con tain s two bon ey projection s: th e coracoid an d th e acrom ion . Th e coracoid serves as th e poin t of origin for th ree m uscles (th e sh ort h ead of th e biceps, th e coracobrach ialis, an d th e pectoralis m in or) as well as the attachm ent point for two ligam ents that stabilize th e AC join t an d th e coracoacrom ial (CA) ligam en t. Th e acrom ion is an exten sion of th e scapular spin e an d provides th e poin t of origin for a portion of th e deltoid m uscle as well as the scapular side of the AC joint. The supraspinatus and an terior portion of the infraspinatus run un dern eath th e in ferior portion of th e acrom ion as th ey

Spine of scapula

Supraspinous fossa

Scapula Acromion

Coracoid process

Clavicle Shaft Acromial end of clavicle Acromioclavicular joint

Figure 13.2 The clavicle is an S-shaped bone

Sternal end of clavicle

that serves as a strut to maintain the normal relationship of the shoulder girdle to the body. (From Oatis CA. Kinesiology. The mechanics and pathomechanics of human movement. Baltimore: Lippincott Williams & Wilkins, 2003, with permission.)

Chapter 13: The Shoulder

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Anatomic neck Greater tuberosity Bicipital groove

Lesser tuberosity 135°

30° retroversion

Figure 13.3 The proximal humerus consist of the humeral head and the greater and lesser tuberosities. The highest point of the humeral head is 5–10 mm above the top of the greater tuberosity. The articular surface is angled superiorly 135 degrees and is in 30 degrees of retroversion when compared to the transepicondylar axis of the elbow.

transverse laterally toward their in sertion on the proxim al hum erus.

Glenohumeral Joint Th e GH join t h as th e largest RO M of any join t in th e body. Th is extrem e ROM com es at th e cost of stability, an d th e GH

Figure 13.4 The primary blood supply of the humeral head is the

arcuate artery, which is a branch of the anterior humeral circumflex artery. (From Craig EV. Master Techniques in Orthopaedic Surgery: The Shoulder, 2nd ed. Philadelphia: Lippincott Williams & Wilkins, 2004, with permission.)

join t is th erefore th e m ost frequen tly dislocated m ajor join t. Only 20% to 30% of the articular surface of the hum eral h ead is in con tact with th e sh allow glen oid at any given tim e. This relationship has very little inheren t stability and h as been compared to a golf ball sittin g on a tee (Fig. 13.6). Th e stability of th e articulation is en h an ced by th e labrum , a triangularly shaped fibrous ring attached to periph ery of th e glen oid th at en h an ces th e glen oid depth by up to 50% (Fig. 13.7). Although sim ilar in appearance to the m eniscus of th e kn ee, th e labrum is m ade of fibrous tissue rath er th an fibrocartilage. Th e rem ain in g stability of th e GH join t is provided by the capsular structures, which provide prim arily static restraint at the extrem es of the ROM, and the rotator cuff m uscles, wh ich are dyn am ic stabilizers th rough th e fun ction al arch of m otion . Wh en viewed from its extern al surface (as in open surgery), th e GH join t capsule appears to be a bland fibrous structure; h owever, when seen internally (as in arthroscopy or h istologic section ) th e capsule is foun d to con tain several discrete ligam en ts, each with a specific fun ction (Figs. 13.8 and 13.9). The GH ligam ents originate from various locations on the glenoid rim an d labrum , for which they are n am ed, and attach to the proxim al h um erus distal to th e articular surface. Th e superior glen oh um eral ligam en t (SGHL) is th e prim ary restraint to inferior translation and extern al rotation with th e arm in adduction . Th e m iddle glen oh um eral ligam ent (MGHL) is not present in all individuals but, wh en it is, it resists an terior translation with the arm at 45 degrees of abduction. Th e inferior glenohum eral ligam ent is divided into an terior (AIGHL) and posterior (PIGHL) ban ds, with

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Coracoid Coracoid Anterior Posterior Acromion

Glenoid fossa

Figure 13.5 Anterior and posterior view of the scapula demonstrating the multiple muscle attach-

ments as well as the glenoid, coracoid, and acromion. (From Iannotti JP, Williams GR. Disorders of the Shoulder: Diagnosis and Management, 2nd ed. Philadelphia: Lippincott Williams & Wilkins, 2007, with permission.)

TABLE 13.1

MUSCULAR ATTACHMENTS TO THE SCAPULA Scapulohumeral Muscles Long head of biceps Short head of biceps Deltoid Coracobrachialis Teres major Long head of triceps Scapulothoracic Muscles Levator scapulae Omohyoid Rhomboid major Rhomboid minor Serratus anterior Trapezius Pectoralis minor Rotator Cuff Muscles Supraspinatus Infraspinatus Subscapularis Teres Minor Seventeen muscles attach the scapula to the neck, thorax, and humerus, making it the control tower for coordinated upper-extremity activity. From Iannotti JP, Williams GR. Disorders of the shoulder: Diagnosis and management, 2nd ed. Philadelphia: Lippincott Williams & Wilkins, 2007, with permission.

an intervening pouch. These inferior ligam ents becom e taut at 90 degrees of abduction . In this position, the AIGHL is the prim ary restraint against anterior translation and the PIGHL resists posterior tran slation . Th e in ferior capsular pouch also cradles th e h um eral h ead in abduction , furth er en h an cin g stability.

Acromioclavicular Joint Th e AC join t con sists of a fibrocartilagin ous disk in terposed between th e distal clavicle an d th e acrom ion . With agin g, n atural degen eration of th is disk occurs, often leading to arthritis of the AC joint. Fortunately, this arthritis is often asymptom atic. Stability is provided by the join t capsule, wh ich surroun ds th e join t circum feren tially. Th e superior an d posterior aspects of the capsule are the m ost important h orizon tal stabilizers of th e AC join t, wh ereas th e coracoclavicular (CC) ligam ents are the m ost importan t vertical stabilizers. These ligam en ts run between the coracoid process and the distal clavicle and consist of the m edial conoid an d lateral trapezoid ligam ent (Fig. 13.10).

Sternoclavicular Joint Th e SC join t is th e m edial articulation between th e clavicle an d the m an ubrium of the sternum . Th is joint is supported


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Figure 13.6 The glenohumeral

joint has been compared to a golf ball sitting on a tee. (From Boardman ND III, Fu FH. Shoulder biomechanics. In: McGinty JB, Cas-pari RB, Jackson RW, Poehling GG, eds. Operative Arthroscopy. Philadelphia: Lippincott-Raven, 1996:627, with permission.)

by a stron g capsular ligam ent (SC ligam en t) as well as by the costoclavicular ligam en t, which is a robust structure linking the m edial clavicle to the first rib (Fig. 13.10). The posterior SC ligam en t h as been sh own to be th e m ost im portan t structure in preven tin g both an terior an d posterior instability of this joint. Disorders of th e SC join t are m uch less com m on th an path ology of th e oth er four articulation s with in th e sh oulder girdle; h owever, th e join t is susceptible to a n um ber of con dition s in cludin g degen erative arth ritis, spon tan eous subluxation , an d septic arth ritis. O f particular importance, posterior dislocation of this joint can lead to compression of th e un derlyin g trach ea an d great vessels. Th ese dislocations generally require reduction in th e

operatin g room , with a th oracic surgeon im m ediately available.

Scapulothoracic Articulation Th e an terior aspect of th e scapula is covered by th e subscapularis m uscles, wh ose an terior side articulates with

Figure 13.8 Arthroscopic view from the posterior portal of the Figure 13.7 The glenoid labrum increases the depth and surface

area of the glenoid socket, which improves stability of the glenohumeral joint. (From Iannotti JP, Williams GR. Disorders of the Shoulder: Diagnosis and Management, 2nd ed. Philadelphia: Lippincott Williams & Wilkins, 2007, with permission.)

anterior capsular structures of a left shoulder. HH, humeral head; G, glenoid; B, biceps tendon; SGHL, superior glenohumeral ligament; SS, subscapularis tendon; MGHL, middle glenohumeral ligament; IGHL, inferior glenohumeral ligament. (From Chapman MW, Szabo RM, Marder RA, et al. Chapman’s orthopaedic surgery. Philadelphia, Lippincott Williams & Wilkins, 2001, with permission.)

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Biceps tendon Superior glenohumeral ligament

Posterior capsule

An t e r io r P o s t e r io r

Middle glenohumeral ligament

Posterior band

Anterior band

Axillary pouch Inferior glenohumeral ligament complex

Figure

13.9 Capsuloligamentous

anatomy viewed from the side with the anterior aspect to the right and the posterior aspect to the left. The humeral head has been removed, leaving the glenoid. The superior glenohumeral ligament and middle glenohumeral ligament are labeled. The inferior glenohumeral ligament complex consists of an anterior band, posterior band, and interposed axillary pouch. The posterior capsule is the area above the posterior band. The biceps is also labeled. (Adapted from O’Brien SJ, Neves MC, Arnoczky SP, et al. The anatomy and histology of the inferior glenohumeral ligament complex of the shoulder. Am J Sports Med 1990;18:449–456, with permission.)

Figure 13.10 The acromioclavicular joint is stabilized by the joint capsule and the coracoclavicular

ligaments, while the sternoclavicular joint is stabilized by the costoclavicular and sternoclavicular ligaments. (From Iannotti JP, Williams GR. Disorders of the Shoulder: Diagnosis and Management, 2nd ed. Philadelphia: Lippincott Williams & Wilkins, 2007, with permission.)


507

Figure 13.11 Location of the scapulotho-

racic bursa. (From Iannotti JP, Williams GR. Disorders of the Shoulder: Diagnosis and Management, 2nd ed. Philadelphia: Lippincott Williams & Wilkins, 2007.)

the posterior thoracic cage. Th ese surfaces are separated by several scapulothoracic bursa that aid in m otion at th is interface (Fig. 13.11). Occasionally, these bursa can becom e inflam ed and lead to posterior shoulder pain. Wh en this inflam m ation is due to abnorm al m echanics used to compensate for oth er deficits within the shoulder com plex, th e pain n orm ally resolves with correction of th e un derlyin g problem . Wh en th e in flam m ation is th e prim ary path ology, it often respon ds to con servative treatm en t using physical therapy and occasion ally steroid injections.

Subacromial Space Th e subacrom ial space is located between th e superior aspect of th e superior rotator cuff ten don s an d th e in ferior aspect of the acrom ion. With in th is space, the subacrom ial bursa h elps to facilitate m otion between th e two opposin g surfaces (Fig. 13.12). In flam m ation of this bursa, narrowing of the space, or degeneration of the rotator cuff ten don s with in th e space is a com m on source of sh oulder pain , as discussed in th e section on rotator path ology.

Figure 13.12 The subacromial bursa is between the rotator cuff and the overlying acromion.

When a full-thickness rotator cuff tear is present, this bursa communicates with the glenohumeral joint. (From Agur AMR, Dalley AF. Grant’s Atlas of Anatomy, 11th ed. Philadelphia: Lippincott Williams & Wilkins, 2005.)

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Rotator Cuff Muscles A large n um ber of m uscle groups con tribute to n orm al m ovem en t of th e sh oulder. Th ese m uscles can be divided in to groups th at prim arily fun ction to stabilize th e sh oulder, m ove th e sh oulder, or m ove th e scapula. Im m ediately superficial to th e GH joint capsule is a set of four m uscles called the rotator cuff. Alth ough th ese m uscles contribute to rotation and elevation about the GH joint, their prim ary purpose is to keep the h um eral head centered with in glen oid cavity wh ile th e larger, m ore powerful m uscles of th e sh oulder complex m ove th e arm . All four m uscles origin ate on th e scapula an d coalesce as a ten dinous cuff to insert on to the greater an d lesser tuberosities of th e proxim al h um erus (Fig. 13.13). Th e supraspin atus cuff m uscle is m ost frequen tly in volved in rotator cuff

path ology. It origin ates from th e suprascapular fossa an d inserts on the anterior portion of the greater tuberosity. As th e supraspin atus ten don passes laterally, it run s un dern eath th e CA arch th at is form ed by th e an terior acrom ion and the CA ligam ent. The in fraspinatus m uscle originates from the infraspinatus fossa of the scapula and inserts on to th e greater tuberosity im m ediately posterior to th e supraspinatus. The infraspinatus plays a m ajor role in m oving the arm , providing the m ajority of external rotation strength . Both the supra- an d infraspinatus are innervated by the suprascapular nerve, wh ich arises from the superior trunk of th e brachial plexus an d passes posteriorly through th e suprascapular n otch . After in n ervatin g th e supraspin atus, th e nerve then passes through the spinoglen oid n otch before in n ervatin g th e in fraspin atus. In jury or com pression of th e n erve in th e suprascapular n otch will lead to atrophy

Figure 13.13 The four rotator cuff muscles originate on the scapula and insert on the greater and lesser tuberosities of the proximal humerus. The long head of the biceps tendon runs in a groove between the two tuberosities. (From Agur AMR. Grant’s Atlas of Anatomy, 9th ed. Philadelphia: Williams and Wilkins, 1991.)


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Figure 13.14 A: Contraction of the anterior and posterior rotator cuff muscles provides a com-

pressive force that keeps the humeral head centered in the glenoid during rotation of the arm. B: During elevation of the arm, the inferior and medially directed force generated by the rotator cuff keeps the humeral head centered in the glenoid and allows the force generated by the deltoid to rotate humeral head. (From Iannotti JP, Williams GR. Disorders of the Shoulder: Diagnosis and Management, 2nd ed. Philadelphia: Lippincott Williams & Wilkins, 2007.)

of both m uscles, wh ereas in jury at th e spin oglen oid n otch will cause isolated atrophy of th e in fraspin atus. Th e teres m in or arises below th e in fraspin atus an d attach es posteriorly on th e greater tuberosity. Th e m uscle is inn ervated by the axillary nerve as th e nerve passes posteriorly just below th e m uscle th rough th e quadran gular space (Fig. 13.12). Like the in fraspinatus, it is an extern al rotator of th e arm but is m ore effective with th e arm at 90 degrees of elevation . Anteriorly, originatin g from the subscapular fossa, lies the subscapularis m uscle. It inserts onto th e lesser tuberosity and is inn ervated by the upper and lower subscapular nerves. The subscapularis con tributes to internal rotation of th e arm . Con traction of th e rotator cuff m uscles stabilizes th e GH join t by providin g a com pressive force across th e join t (Fig. 13.14). The cuff m uscles also act as a force couple with th e deltoid to allow for elevation of th e arm . A force couple is a paired set of coordin ated m uscle con traction s th at togeth er achieve a fun ction not possible by either m uscle group acting alone. If the deltoid were to con tract without th e rotator cuff, the hum eral head would simply slide superiorly on the glenoid. When both the deltoid an d rotator cuff m uscles fire togeth er, th e overall m edial an d in ferior vector gen erated by the cuff m uscles keeps the hum eral h ead centered on th e glen oid, an d th e force gen erated by th e deltoid leads to rotation of th e h um eral h ead an d elevation of th e arm . Between the an terior border of th e supraspinatus ten don an d superior border of th e subscapularis ten don lies a triangularly shaped area of uncovered capsule kn own as the rotator interval. Th is in terval con tain s th e SGHL, th e coracohum eral ligam ent, and the long head of the biceps ten don (LHBT). Th e fun ction of th e LHBT rem ain s con troversial, with som e authors believing it plays a m ajor role

in depressin g th e h um eral h ead, especially wh en a deficiency of the rotator cuff is presen t. Others believe that its fun ction al purpose is in con sequen tial an d th at it is a significant source of pain. The tendon originates from th e supraglen oid tubercule an d superior glenoid labrum and runs laterally through the GH joint to exit out the bicipital groove (Figs. 13.9 an d 13.13). Tears of th e subscapularis m uscles are often associated with m edial in stability of the LHBT. Given its close anatom ic proxim ity, pathology of th e supraspin atus is often associated with ten din osis of the LHBT within the GH joint.

Glenohumeral Movers Th e prim ary m uscles respon sible for gen eratin g m otion and power about the GH joint are the deltoid, pectoralis m ajor, latissim us dorsi, and teres m ajor (Fig. 13.15). The deltoid is th e largest m uscle of th e sh oulder girdle, with an anterior head arising from the m id to lateral clavicle, a m iddle h ead arisin g from th e lateral acrom ion , an d a posterior h ead that arises from th e scapular spin e. All th ree h eads coalesce to in sert on th e deltoid tuberosity of th e proxim al h um erus. Inn ervation is via th e axillary n erve, wh ich passes posteriorly th rough th e quadran gular space an d th en wraps back aroun d th e arm an teriorly on th e deep surface of th e deltoid m uscle (Fig. 13.16). The n erve travels 5 cm below th e tip of th e lateral acrom ion as it passes in an an terior direction from th e m iddle to th e an terior deltoid. Wh en splittin g the deltoid between th e anterior an d lateral heads to access the rotator cuff, it is important that the split does n ot exten d greater th an 5 cm below th e lateral acrom ion in order to avoid in jurin g th e n erve an d dein n ervatin g th e an terior deltoid. Th e prim ary action of th e deltoid is elevation

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A

B Figure 13.15 Anterior (A) and posterior (B) views of the primary movers of the glenohumeral joint, which are the deltoid, pectoralis major, latissimus dorsi, and teres major. (From Moore KL. Clinically Oriented Anatomy, 3rd ed. Baltimore: Williams & Wilkins, 1992, with permission.)


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Figure 13.16 The axillary nerve passes posteriorly through the quadrangular space and then

wraps back around the humerus anteriorly on the undersurface of the deltoid muscle. (From Moore KL. Clinically Oriented Anatomy, 3rd ed. Baltimore: Williams & Wilkins, 1992, with permission.)

of th e arm , alth ough th e an terior an d posterior h eads also con tribute to internal and external rotation of the arm . Th e pectoralis m ajor origin ates from th e m an ubrium of the sternum , first six ribs, and m edial two thirds of the clavicle. It inserts on the lateral lip of the bicipital groove and is in nervated by the m edial and lateral pectoral n erves. The m uscle is important for forward flexion, adduction, and intern al rotation of th e arm . In cases of irreparable subscapularis tears, the pectoralis m ajor can be tran sferred to the lesser tuberosity to substitute for the an terior rotator cuff. Th e latissim us dorsi arises posteriorly from a large aponeurosis between T7 and L5 as well as the sacrum , ilium , and occasionally the lower three or four ribs and inferior scapular an gle to in sert on th e m edial lip of th e bicipital groove. In n ervation is via th e th oracodorsal n erve. Activation of the m uscle in ternally rotates, adducts, an d extends the arm . The latissim us can be transferred to substitute for irreparable tears of the supra- and in fraspinatus. Th e teres m ajor origin ates from th e posterior scapula’s inferior lateral border and attaches just m edial to the latissim us on the m edial aspect of the bicipital groove. It provides internal rotation, adduction, and exten sion of the arm an d is inn ervated by the lower subscapular nerve.

Scapular Movers In everyday life, th e m ajority of m ovem en ts about th e sh oulder complex consist of composite m otion at both th e GH an d scapuloth oracic articulation . Because th e scapula’s on ly bon ey articulation with th e axial skeleton is via th e AC joint, a group of large m uscles is required not only to m ove the scapula but to stabilize it on the posterior aspect of th e th orax. Th e m uscles respon sible for scapular m ovem en t an d stability include the trapezius, levator scapulae, rh om boids, an d serratus an terior (Fig. 13.17).

Th e trapezius is th e largest of th e scapuloth oracic m usculature an d is in n ervated by th e spin al accessory n erve. The m uscle origin ates from th e spin ous processes of C7 th rough T12 an d in serts alon g th e scapular spin e, acrom ion , an d distal th ird of th e clavicle. Th e trapezius is respon sible for retraction an d upward rotation of th e scapula. Injury to th e spin al accessory nerve, especially after th e dissection of lymph n odes in th e n eck for th e treatm en t of can cer, can lead to a palsy of th e trapezius m uscles an d lateral win gin g of th e scapula. In th is con dition , th e m edial border of th e scapula will ride off or “wing’’ from th e posterior chest wall (Fig. 13.18). The inferior tip of the scapula will also sit laterally compared with th e opposite side. This deform ity can be exaggerated by havin g the patient elevate his arm or perform a wall push -up. Th e secon d m ajor scapular rotator is th e serratus an terior m uscle, wh ich origin ates as fleshy slips alon g th e an terolateral first th rough n in th ribs an d in serts alon g th e an terior surface of th e scapula’s m edial boarder. Inn ervated by the lon g th oracic n erve, th e serratus protracts an d upwardly rotates th e scapula. Palsy of th e serratus m uscle will also lead to scapular win gin g, but th e win gin g will be m edial in stead of lateral. Th e m edial boarder of th e scapula will continue to wing, but the in ferior tip will ride m edial and superior wh en compared with th e opposite side. As with lateral win gin g, th e deform ity can be exaggerated with elevation of th e arm or a wall push -up. Th e levator scapula an d rh om boids serve to retract an d in feriorly rotate th e scapula. Th e levator scapula lies deep to th e trapezius an d arises from th e tran sverse processes of C1 to C3. It in serts on th e superior border of th e m edial scapula and is inn ervated by deep branches of C3 an d C4, as well as by th e dorsal scapula n erve. Th e rh om boid m in or an d m ajor origin ate from th e spin ous processes of C7 to

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Orthopaedic Surgery: Principles of Diagnosis and Treatment Levator scapulae

Trapezius (upper portion)

Rhomboid minor

Rhomboid major

Trapezius (lower portion)

A

Serratus anterior

Latissimus dorsi

B

Figure 13.17 The scapular rotators. A: The trapezius and serratus anterior are the primary upward rotators of the scapula. B: The rhomboids, levator scapula, and latissimus dorsi are responsible for downward rotation. (From Iannotti JP, Williams GR. Disorders of the Shoulder: Diagnosis and Management, 2nd ed. Philadelphia: Lippincott Williams & Wilkins, 2007, with permission.)

T5 an d in sert alon g th e m edial border of th e scapula. Th ey are in n ervated by th e dorsal scapular n erve.

Neurovascular Structures Although the blood supply to th e proxim al hum erus an d in n ervation of th e various m uscles surroun din g th e

sh oulder h as been previously discussed, it is extrem ely im portan t to keep in m in d th e close proxim ity of th e m ajor n eurovascular structures of th e upper extrem ity to th e sh oulder girdle. Th e axillary artery and vein, surrounded by the brachial plexus, typically lie m edially and distally to th e coracoid process (Fig. 13.19). Dam age to th ese vital structures followin g traum atic injuries to the shoulder region is uncom m on but certainly can occur. Missing such dam age, especially wh en it in volves th e vasculature, can h ave catastroph ic con sequen ces.

EVALUATION OF SHOULDER PROBLEMS Th e m ost com m on sh oulder complain ts are pain , weakn ess, stiffn ess, an d in stability. Despite th e widespread use of soph isticated im agin g m odalities, a th orough h istory an d physical exam ination rem ain the m ost important tools in the evaluation of shoulder disorders.

History Figure 13.18 Weakness of the serratus anterior or trapezius muscles can lead to scapular winging. (From Krishnan SG, Hawkins RJ, Warren RF. The Shoulder and the Overhead Athlete. Philadelphia: Lippincott Williams & Wilkins, 2004, with permission.)

For all patien ts presen tin g with upper extrem ity com plain ts, the history should begin with their age, dom inant hand, an d occupation. Age is particularly importan t when evaluatin g sh oulder problem s, because m any of th e com m on pathologies affecting the shoulder have a m arked


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Figure 13.19 The axillary vessels and brachial plexus lie medial and distal to the coracoid process. (From Chapman MW, Szabo RM, Marder RA, et al. Chapman’s Orthopaedic Surgery. Philadelphia: Lippincott Williams & Wilkins, 2001, with permission.)

predilection for certain age groups. Patien ts un der th e age of 30 are m ore likely to experien ce GH in stability or labral lesions, whereas rotator cuff pathology and arthritis are m ore com m on in elderly patients. Next, it is im portan t to ask th e patien t to describe h is problem . Patien ts will gen erally complain of pain , weakness, stiffness, instability, or a traum atic event. For each of these complaints, it is important to note the acuity of on set, duration , frequen cy, an d severity of th e sym ptom s. In patients who have experien ced a traum atic in jury, the exact nature of the injury and position of th e extrem ity at th e tim e of th e in jury are importan t. Th e fun ction of th e sh oulder prior to th e in jury sh ould also be n oted, as th is can in fluen ce decision m akin g wh en evaluatin g th e patien t’s physical exam ination an d im aging fin dings. It is important to question th e patien t regardin g litigation con cern in g any in jury. Likewise, th e exam in er sh ould in quire as to wh eth er the patient began experiencing symptom s or was injured wh ile workin g. Un fortun ately, th e literature h as dem on strated th at the outcom es for th e treatm ent of pathology about th e shoulder are significantly worse for patients who are involved in worker’s compensation claim s. Pain is the m ost com m on shoulder problem . Its location about th e joint is important. Pain over the superior shoul-

der is often due to disorders of th e AC join t, wh ereas pain over th e trapezius m ay be referred from th e cervical spin e or secon dary to fatigue wh en th e patien t is attem ptin g to compensate for GH or subacrom ial path ology through increased scapulothoracic m otion. Rotator cuff pathology is alm ost always associated with pain over th e lateral aspect of th e upper arm , wh ereas GH arth ritis leads to a dull ach e within the sh oulder join t that is exacerbated with m otion. Radiation of pain is an importan t con sideration . In gen eral, pain from sh oulder problem s does n ot radiate below the elbow. If the patien t is complaining of pain that radiates to th e forearm or h an d, oth er sources of path ology, such as periph eral n erve compression or cervical spin e disease, sh ould be suspected. Th e n ature of th e patien t’s pain an d any exacerbatin g m ovem en ts sh ould be obtain ed. Burn in g pain suggests a n eurologic cause. Pain from rotator cuff path ology and im pin gem en t syn drom e is often described as a dull ach e th at is exacerbated by overh ead activities an d reach in g beh in d the back. These patients will often complain that the pain wakes th em from sleep, especially wh en th ey lie on th e in volved side. As in oth er areas of th e body, severe n igh t or rest pain sh ould always raise con cern for n eoplasm or in fection .

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Patien ts with decreased m otion of the shoulder m ay complain of stiffness. They m ay also complain of pain occurring prim arily at the extrem es of their ROM. Weakn ess is another com m on complaint. In these patients, it is im portan t to attem pt to determ in e wh eth er th ey feel weak because of associated pain or wh eth er th ey actually lack strength. Wh en a patient complains of instability, th e etiology, frequen cy, direction , an d severity of th e in stability sh ould be recorded. Cervical spin e path ology often leads to pain th at is referred to the shoulder region; th erefore, all patients with sh oulder pain should be questioned regardin g neck pain an d neurologic symptom s radiating down th e arm . Finally, the specifics and efficacy of any previous treatm ent that the patien t m ay h ave already received for h is sh oulder com plain t sh ould be obtain ed. Th is in cludes th e location (i.e., subacrom ial, GH, trigger point) and num ber of any injections, an d th e duration an d n ature of any physical th erapy program s.

Physical Examination Th e physical exam in ation of th e sh oulder in volves th e sam e basic elem en ts as exam in ation of th e oth er join ts in th e m usculoskeletal system in cludin g in spection , palpation , ROM, stren gth testin g, an d n eurovascular exam in ation . Addition ally, several special tests are useful in th e evaluation of specific pathologic con ditions (Table 13.2). Each of th ese tests n eed n ot be perform ed on every patien t. In stead, on ly those m an euvers related to suspected pathology, as determ in ed by th e h istory an d basic elem en ts of th e physical exam in ation , sh ould be perform ed. Th is section describes the basic elem en ts of the physical exam ination; the specific tests are described in th e physical exam in ation section s of the conditions that th ey evaluate.

TABLE 13.2

SPECIAL TESTS FOR EXAMINATION OF THE SHOULDER Test

Condition Examined

Neer impingement sign Hawkins impingement sign Jobe test External rotation lag sign Hornblower sign Lift-off test Belly-press test Apprehension test Relocation test Load and shift test Sulcus sign O’Brien test Mayo sheer test

Impingement Impingement Rotator cuff weakness, impingement Infraspinatus weakness Infraspinatus and teres minor weakness Subscapularis weakness Subscapularis weakness Glenohumeral instability Glenohumeral instability Glenohumeral laxity Inferior glenohumeral laxity SLAP tear SLAP tear

Given th e close an atom ic location an d frequen t overlap in presenting symptom s, it is important to begin the exam ination of all patien ts with shoulder pain with a brief exam in ation of th e cervical spin e. Pain or stiffn ess with rotation or flexion / exten sion of th e n eck can be in dicative of cervical disease an d sh ould prompt a m ore th orough workup.

Inspection Th e patien t m ust be appropriately gown ed to allow in spection of both shoulders and the neck. Exam ination begin s with in spection of th e sh oulders for asym m etry, m asses, swelling, erythem a, ecchym oses, and m uscle atrophy. Th e location an d con dition of any previous surgical in cisions should be noted. As with all elem ents of the shoulder exam in ation , com parison of th e two sides is essen tial. Ecchym oses m ay be presen t in a n um ber of traum atic sh oulder con dition s in cluding fractures, dislocations, m uscle ruptures, and large, acute rotator cuff tears. Prom inence of th e distal clavicle at th e AC join t is a com m on fin din g after AC separation or osteophyte form ation with AC arthritis. Atrophy of the m uscles about the shoulder can occur with disuse secon dary to pain , ten don rupture, or following de-innervation . When longstandin g rotator cuff tears lead to m uscle atrophy, hollowing often occurs over the supraspinatus an d in fraspinatus fossa. Atrophy of the deltoid m uscle, especially followin g traum atic in jury or previous surgery, sh ould raise con cern for in jury to th e axillary n erve. In spection of th e position of th e scapula on th e posterior ch est wall is important. Winging of the scapula can indicate weakn ess of th e serratus an terior or trapezius (Fig. 13.18). Wh ile viewed posteriorly, th e patien t sh ould be asked to raise both h an ds overh ead wh ile th e exam in er in spects for scapulothoracic rhythm , which sh ould be sm ooth and sym m etric. Abn orm alities can be due to scapulothoracic bursitis or scapular win gin g. Th ey m ay also be secon dary as th e patient attempts to compensate for stiffness or pain in other aspects of th e shoulder complex. Palpation Palpation begins m edially at the SC join ts and contin ues laterally alon g the clavicle, AC joint, coracoid, acrom ion, an d scapular spine. Patients with SC or AC joint pathology will gen erally be ten der directly over th ose join ts. Th e in sertion of th e rotator cuff tendons on the greater tuberosity can be palpated through th e deltoid m uscle lateral to the acrom ion and is often tender in patients with impingem en t or rotator cuff tears. Tenderness to palpation over the trapezius is often seen with cervical spin e pathology or with m uscle spasm durin g scapuloth oracic compen sation for GH abn orm alities. Range of Motion In th e traum atized or obviously fractured or dislocated sh oulder, ROM assessm ent should be con sidered only after


515

Figure 13.21 External rotation with the arm at the side is as-

sessed by asking the patient to place her elbow at the side of the body and flex it 90 degrees. The patient is then asked to externally rotate the forearm while maintaining the elbow at her side.

opposite h an d. At n eutral rotation , th e forearm is parallel to th e floor; at 90 degrees of external rotation, the forearm is parallel to the body with the hand pointing toward th e ceilin g. Th is is followed by in tern al rotation , wh ich is

Figure 13.20 Forward elevation is assessed by asking the patient to raise her hands directly overhead.

review of radiograph s. In all oth er patien ts, both active an d passive RO M sh ould be evaluated for forward elevation an d intern al and extern al rotation. Forward elevation is a com posite of GH an d scapuloth oracic m otion an d is assessed by askin g th e patien t to raise his hands directly overhead (Fig. 13.20). Internal and extern al rotation are evaluated with th e arm both at th e side an d at 90 degrees of abduction. For external rotation with the arm at the side, the patient’s elbow is placed at the side of th e body an d flexed 90 degrees. Glen oh um eral rotation is then m easured by rotating th e forearm laterally while the elbow is stabilized at th e side (Fig. 13.21). Zero degrees is achieved wh en th e forearm points straight ahead, whereas 90 degrees is ach ieved wh en th e forearm is position ed in line with the shoulders. Internal rotation is assessed by having the patient put the h an d beh in d the back to touch as high as possible, notin g the relationship of the thum b to th e tip of th e spin al colum n (Fig. 13.22). As a referen ce, the spine of th e scapula is considered approxim ately at the T2 level an d th e tip at T7. For rotation with th e arm at 90 degrees of abduction , the arm is abducted 90 degrees in the plane of the scapula with th e elbow in 90 degrees of flexion (Fig. 13.23). Th e exam in er th en uses on e h an d to extern ally rotate th e patient’s arm while steadying the patien t’s elbow with the

Figure 13.22 Internal rotation is assessed by asking the patient

to put her hand behind her back and touch as high as possible. The relationship of the thumb to the spinous processes of the vertebral bodies is used as a reference for measurement. This patient has internal rotation to the T5 level.

516


A

B

Figure 13.23 A–C: For rotation with the arm at 90 degrees of ab-

C

duction, the arm is abducted 90 degrees in the plane of the scapula with the elbow in 90 degrees of flexion (A). The arm is then maximally externally (B) and then internally (C) rotated.

m easured by rotatin g th e h an d toward th e floor an d n otin g the degrees of downward rotation from the n eutral position .

Strength Testing Stren gth testin g about th e sh oulder focuses on evaluation of th e rotator cuff. Th e supraspin atus is best evaluated by testin g resisted abduction in th e plan e of th e scapula of th e exten ded, in tern ally rotated arm . Th is is kn own as th e Jobe test or th e “empty can ’’ sign . Th e patien t is asked to resist down ward pressure from th e exam in er with th e sh oulder abducted 90 degrees, th e elbow exten ded, an d th e th um b poin tin g down ward toward th e floor (Fig. 13.24). Weakness with this m aneuver can be indicative of supraspin atus dysfun ction , alth ough it can be difficult to distin guish true weakness from weakness secondary to pain. Furth erm ore, som e patients with full-thickness tears of the supraspin atus ten don will exh ibit m in im al stren gth deficits with th is test. The posterior rotator cuff m uscles (infraspin atus an d teres m in or) are evaluated by testin g extern al rotation stren gth of the arm with th e elbow at the side (Fig. 13.25). Sign ifican t weakn ess in extern al rotation sh ould be evaluated with lag sign s. With th e elbow flexed 90 degrees an d at

Figure 13.24 Jobe test is performed by having the patient

abduct the shoulder 90 degrees in the plain of the scapula and internally rotate the arm (thumb pointing toward the floor). The patient is then asked to resist a downward force applied by the examiner. The test can be performed separately on each side, or both shoulders can be tested simultaneously. (From Schepsis AA, Busconi BD. Orthopaedic Surgery Essentials: Sports Medicine. Philadelphia: Lippincott Williams & Wilkins, 2006, with permission.)


Figure 13.25 The posterior rotator cuff is evaluated by testing external rotation strength with the elbow at the side. (From Johnson DH, Pedowitz RA. Practical Orthopaedic Sports Medicine and Arthroscopy. Philadelphia: Lippincott Williams & Wilkins, 2007, with permission.)

the side, the forearm is placed in m axim al extern al rotation by the exam iner. As the exam iner releases th e forearm , the patient is asked to m ain tain it in m axim al external rotation (Fig. 13.26). If th e patien t is un able to do so, th e sign is con sidered positive, and a tear or dysfun ction of the infraspinatus sh ould be suspected. An in ability to m aintain

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the 90-degree abducted arm in m axim al extern al rotation is kn own as th e Horn blower sign an d is in dicative of path ology of th e lower h alf of th e in fraspin atus an d teres m in or (Fig. 13.27). Two m an euvers h ave been described to evaluate subscapularis stren gth . For th e lift-off test, th e patient is asked to lift h is h an d away from th e lower back (Fig. 13.28). In ability to lift an d m ain tain th e h an d off th e back is con sidered a positive test an d in dicates subscapularis weakn ess. Th e belly press test can also be used to evaluate subscapularis stren gth . Th e patien t is asked to place h is h an d on h is abdom en and internally rotate th e sh oulder so th at the elbow is in fron t of th e trun k. Th e patien t is th en asked to press down on h is abdom en wh ile m ain tain in g th e elbow in fron t of th e plan e of th e body. With subscapularis weakn ess, the elbow will fall posteriorly when the patient attempts to push on h is abdom en (Fig. 13.29). Th e stren gth of th e scapular stabilizers can be evaluated by asking the patient to perform a wall push -up when there is a suggestion of scapular win gin g. For patien ts with sign ifican t weakn ess or atrophy about th e sh oulder, th e larger GH m overs can be evaluated for integrity and function by testin g resistan ce again st th eir prim ary direction of m otion . For exam ple, th e deltoid is evaluated by resisted abduction an d th e pectoralis m ajor is tested by resisted adduction of the arm in 90 degrees of forward flexion.

Neurovascular Assessment Th e m ajority of th e n eurologic exam in ation h as already been com pleted by evaluation of th e stren gth of th e m uscles about th e sh oulder. Motor fun ction of th e rem ain in g m ajor nerves to the arm can be tested by resisted elbow flexion (m usculocutan eous), elbow exten sion (radial), finger flexion (m edian ), fin ger abduction (uln ar), an d th um b abduction (posterior interosseous). Sensation is evaluated by assessing ligh t touch over th e lateral deltoid (axillary),

A

B Figure 13.26 A lag between maximal passive and active external rotation with the arm at the side

constitutes a positive external rotation lag signs and is associated with infraspinatus weakness. (From Iannotti JP, Williams GR. Disorders of the Shoulder: Diagnosis and Management, 2nd ed. Philadelphia: Lippincott Williams & Wilkins, 2007, with permission.)

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A

B Figure 13.27 An inability to keep the arm in maximal external rotation at 90 degrees of abduction

constitutes a positive Hornblower sign and is associated with weakness of the infraspinatus and teres minor. (From Iannotti JP, Williams GR. Disorders of the Shoulder: Diagnosis and Management, 2nd ed. Philadelphia: Lippincott Williams & Wilkins, 2007, with permission.)

lateral forearm (m usculocutan eous), th um b web space (radial), radial aspect of th e in dex fin ger (m edian ), an d lateral aspect of th e little fin ger (uln ar). For patien ts with suspected n eurologic path ology, a m ore detailed n eurologic exam in cludin g reflex evaluation is n ecessary. Vascular in tegrity sh ould be evaluated by palpatin g th e radial pulse an d m easurin g th e capillary refill tim e for th e fin gers.

Imaging Multiple im agin g m odalities are available for th e evaluation of disorders of th e sh oulder com plex. A stan dard set of plain radiograph s sh ould be obtain ed in all patien ts presen ting with shoulder complain ts. Addition al views and m ore advan ced im agin g tech n iques are th en ordered based

on th e patien t’s h istory, physical exam in ation , an d in itial radiograph ic fin din gs.

Radiographs Th e stan dard radiograph ic exam in ation of th e sh oulder in cludes th e anterior–posterior (AP), scapular Y, an d axillary lateral views. To evaluate the GH joint, it is important to obtain a true AP view of th e sh oulder, n ot of th e ch est. Because th e scapula is an gled an teriorly on th e th orax, the x-ray beam m ust an gled 30 to 45 degrees laterally, so th at the beam is perpendicular to the GH joint (Figs. 13.30 –32). Th e Zan ca view, described below un der th e evaluation of AC sprains, is used to evaluate the AC joint. A variety of

Figure 13.29 A patient with subscapularis weakness will be unFigure 13.28 The lift-off test is used to evaluated subscapularis

strength. (From Krishnan SG, Hawkins RJ, Warren RF. The Shoulder and the Overhead Athlete. Philadelphia: Lippincott Williams & Wilkins, 2004, with permission.)

able to keep his elbow in front of the plane of the body when asked to press down on his belly. This patient’s elbow remains forward on the normal left side, whereas on the right side, the elbow falls posterior making the belly-press test positive. (From Krishnan SG, Hawkins RJ, Warren RF. The Shoulder and the Overhead Athlete. Philadelphia: Lippincott Williams & Wilkins, 2004, with permission.)

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45˚

A

B Figure 13.30 A: The true anterior–posterior (AP) view of the glenohumeral joint is obtained by

angling the beam 30 to 45 degrees from the sagittal plane. B: The true AP shows the glenohumeral joint without overlap of the proximal humerus on the glenoid, as occurs on an AP of the chest. (From (A) Buholz RW, Heckman JD, Court-Brown CM. Rockwood and Green’s Fractures in Adults, 6th ed. Philadelphia: Lippincott Williams & Wilkins, 2006; and (B) Iannotti JP, Williams GR. Disorders of the Shoulder: Diagnosis and Management, 2nd ed. Philadelphia: Lippincott Williams & Wilkins, 2007, with permission.)

additional radiograph ic views have been described to better visualize specific areas of injury associated with GH instability, alth ough th ese tech n iques are utilized less frequen tly owin g to th e widespread use of com puted tom ograph (CT) an d m agnetic resonance im aging (MRI) scans.

Computed Tomography Scans Computed tom ography scans provide a m ore detailed three-dim ensional evaluation of the boney an atomy about the sh oulder. They are the im aging m odality of choice for the evaluation of complex fractures of the proxim al hum erus or scapula. They are also useful for the evaluation of posterior glen oid bon e stock in patien ts bein g con sidered for total sh oulder arth roplasty. Magnetic Resonance Imaging Scans Magn etic resonance im aging scans are the im agin g m odality of ch oice for the evaluation of the soft tissue structures about the sh oulder. Th ey are especially useful for evaluation of disorders of the rotator cuff. As in oth er areas of th e body, T1 weigh ted im ages are best suited for evaluatin g an atom ic structures, wh ereas T2 weigh ted im ages highlight areas of pathology. Standard MRI exam ination of th e sh oulder in cludes axial, coron al oblique, an d sagittal oblique cuts. Th e coron al an d sagittal oblique views are term ed “oblique,’’ because th ey are orien ted parallel an d

perpen dicular to th e plan e of th e scapula wh ich , because of th e scapula’s orien tation on th e ch est wall, is oblique to the plane of the body. Wh en using MRI for the evaluation of rotator cuff tears, it is im portan t to correlate th e patien t’s clinical fin dings with the pathology seen only in the im agin g study. O ver 50% of asymptom atic patien ts older th an 60 years of age will h ave complete or partial rotator cuff tears on MRI scan s. Magnetic resonance im aging is less accurate in the evaluation of disorders of th e glen oid labrum , such as superior labrum anterior to posterior (SLAP) tears and Bankart lesion s. Alth ough th e sen sitivity an d specificity can be in creased with in jection of intra-articular contrast prior to the study, MRI findings con tinue to be less accurate than h istory an d physical exam in ation for th ese disorders.

Ultrasound Ultrasoun d evaluation is rapidly gain in g popularity for th e evaluation of soft tissue path ology about th e sh oulder, especially disorders of th e rotator cuff. Compared to MRI scan s, ultrasound h as th e advantage of being quicker, less expen sive, an d better tolerated by patien ts, an d it allows for dynam ic as well as static exam ination s. O n the downside, th e accuracy is highly operator-dependent an d associated m uscle atrophy an d in tra-articular path ology is n ot well visualized. For th ese reason s, MRI rem ain s th e im agin g

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Arthrography Arthrography involves th e in jection of radiopaque con trast m aterial into the GH join t followed by radiographic evaluation of the shoulder to determ ine the distribution pattern of th e dye. In patien ts with full-th ickn ess tears of th e rotator cuff, the dye will leak through the cuff defect into the subacrom ial space. Although extrem ely accurate in th e detection of full-thickn ess rotator cuff tears, the use of arthrography h as been supplan ted by MRI an d ultrasoun d exam in ation due to their less in vasive n ature an d ability to better detect partial-th ickn ess cuff tears an d ten don itis. Th is study is now reserved for patients un able to undergo an MRI scan in locations where ultrasound is not available.

TRAUMATIC INJURIES TO THE SHOULDER COMPLEX

A

Clavicle Fractures Th e clavicle is th e m ost frequen tly fractured bon e in th e sh oulder com plex. Alth ough the m ajority of these fractures h eal un eventfully with n on operative treatm en t, recent eviden ce suggests th at th e in ciden ce of n on un ion an d th e disability associated with m alunion is m ore significant than was previously thought.

Classification Fractures are classified accordin g to th eir an atom ic location into m edial, m iddle, and lateral thirds. The m ajority of fractures (80%) occur in th e m iddle th ird, wh ere th e bon e is biom ech an ically weakest an d less soft tissue protection is presen t. Fractures of th e lateral th ird are furth er divided accordin g to th e relation sh ip of th e fracture pattern to th e CC ligam en ts an d th e AC join t (Fig. 13.33). Medial fractures are m uch less com m on, accountin g for only 5% of all clavicle fractures. Mechanism of Injury Th e m ost com m on cause of clavicle fractures is a fall on th e involved shoulder. Direct impact to th e clavicle and a fall on an outstretch ed hand are other, less com m on, m echanism s of in jury. B Figure 13.31 A: The Y view is obtained by shooting the x-ray beam parallel to the scapular spine. B: This view visualizes the shape of the acromion and the subacromial space. (From (A) Buholz RW, Heckman JD, Court-Brown CM. Rockwood and Green’s Fractures in Adults, 6th ed. Philadelphia: Lippincott Williams & Wilkins, 2006, with permission.)

m odality of ch oice at m ost cen ters except for th ose patien ts who are unable to un dergo MRI scan s. Ultrasound is especially useful followin g previous rotator cuff surgery, in which postsurgical artifact often m akes MRI scans difficult to in terpret.

Presentation Patients usually presen t with localized pain, swelling, and deform ity over th e clavicle followin g a traum atic in jury. Th e affected arm is often adducted across th e body an d supported by th e opposite hand in an effort to decrease the deform ing forces across the fracture site. Physical Findings Visible deform ity and ecchym osis at the fracture site are com m on. Th e m edial fragm ent can “tent’’ the skin, occasion ally leadin g to a com plete puncture an d an open fracture. It is important to look for, and docum ent, any open woun ds, as th eir presen ce could h ave a sign ifican t im pact on treatm en t. A th orough n eurovascular exam in ation is


A

521

B Figure 13.32 A: The axillary lateral is obtained by aiming the x-ray beam into the axilla with the plate on the superior shoulder. B: The axillary view demonstrates the relation of the humeral head to the glenoid articular surface in the anterior and posterior plane. (From (A) Buholz RW, Heckman JD, Court-Brown CM. Rockwood and Green’s Fractures in Adults, 6th ed. Philadelphia: Lippincott Williams & Wilkins, 2006; and (B) Iannotti JP, Williams GR. Disorders of the Shoulder: Diagnosis and Management, 2nd ed. Philadelphia: Lippincott Williams & Wilkins, 2007, with permission.)

necessary, especially in patients with a high-en ergy m ech anism of in jury. Th e brachial plexus and axillary artery lie in close proxim ity to the inferior surface of the bone and are vulnerable to injury, especially with fractures of the m edial third. The ch est should be auscultated for bilateral breath sounds to rule out a pneum othorax.

Radiographic Evaluation Two views of th e clavicle are n eeded. For m edial clavicle fractures, an AP and an AP with 40 degrees of ceph alic tilt are used. Lateral fractures are better evaluated with an AP, a Zanca view (Fig. 13.34), an d an axillary lateral of the sh oulder.

Figure 13.33 Fractures of the distal clavicle are divided into three types. Type I fractures are

lateral to the cricoclavicular (CC) ligaments. Type II fractures are medial to the CC ligaments or lead to rupture of the ligaments from the medial clavicle. Type III fractures are lateral to the CC ligaments with extension into the acromioclavicular joint. (From Chapman MW, Szabo RM, Marder RA, et al. Chapman’s Orthopaedic Surgery. Philadelphia: Lippincott Williams & Wilkins, 2001, with permission.)

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10˚

X-ray

B

A Figure 13.34 A: The Zanca view is obtained by shooting an anterior-posterior view with 10 de-

grees of cephalic tilt and half of the normal kV. B: The view provides excellent visualization of the acromioclavicular joint and the cricoclavicular space. (From (A) Rockwood CA, Young DC. Disorders of the acromioclavicular joint. In: Rockwood CA, Matsen F III, eds. The Shoulder. Philadelphia: WB Saunders, 1990; and (B) Buholz RW, Heckman JD, Court-Brown CM. Rockwood and Green’s Fractures in Adults, 6th ed. Philadelphia: Lippincott Williams & Wilkins, 2006, with permission.)

Special Tests Special tests are rarely n eeded. If th ere is difficulty un derstanding the fracture pattern , CT scan can be helpful. Th is is especially true for m edial th ird fractures. If, based on th e physical exam in ation , th ere is con cern for vascular in jury, an arteriogram is n eeded. For patien ts with a n eurologic deficit, an electromyograph (EMG) is useful for diagn ostic an d progn ostic purposes but n ot un til 3 to 4 weeks after the in jury. Differential Diagnosis Clavicle fractures m ust be differen tiated from oth er traum atic in juries about th e sh oulder. Th is is easily accom plish ed by physical exam in ation an d radiograph . Wh en evaluatin g in juries about th e AC an d SC join ts in youn ger patien ts, it is im portan t to rem em ber th at th e m edial an d lateral physes often do n ot fuse un til th e late teen s or early twen ties. Suspected AC an d SC dislocation s in th is patien t population are often Salter Harris type I fractures of th e clavicle through th e physis. A CT scan is helpful in m aking this distinction. Treatment Historically, alm ost all m idshaft clavicle fractures were treated n on operatively an d th ough t to h eal with a very low

incidence of nonunion an d residual disability. Nonoperative m anagem ent consists of sling im m obilization for 4 to 6 weeks, followed by a gradual return to activity. Stiffn ess of th e sh oulder is gen erally n ot a problem because th e in jury does n ot in volve th e GH join t. Several recen t studies h ave dem on strated th at, in adults, th e in ciden ce of n on un ion following displaced or com m in uted fractures of the m iddle th ird m ay be as h igh as 20%. Furth erm ore, patien ts wh o h eal with m ore than 1.5 to 2 cm of sh orten in g often have som e residual loss of sh oulder function. These studies have led to an increased interest in operative fixation, either with plates an d screws or in tram edullary pin s, for fractures with greater th at 100% displacem en t, com m in ution , or greater th an 2 cm of sh orten in g (Fig. 13.35). Th e absolute in dications for operative m anagem ent of m iddle-third fractures con tin ue to be open fractures, fractures associated with a n eurovascular in jury, an d fractures in polytraum a patients who need rapid use of the upper extrem ity for weight bearin g. For lateral clavicle fractures, types I an d III are stabilized by the in tact CC ligam ents, so th ey are generally treated nonoperatively. If symptom s persist, they can be treated with excision of the distal clavicle. Because th e CC ligam ents are either disrupted or attached to the lateral piece, type II factures are in h eren tly un stable an d associated


A

523

B Figure 13.35 A: A comminuted fracture of the middle third of the clavicle. Recent evidence

suggests that this type of fracture is more prone to nonunion than previously thought. B: The fracture was treated with open reduction and internal fixation using a plate and screws. (From Buholz RW, Heckman JD, Court-Brown CM. Rockwood and Green’s Fractures in Adults, 6th ed. Philadelphia: Lippincott Williams & Wilkins, 2006, with permission.)

with a h igh rate of n on un ion . Th is h as led m ost auth ors to favor operative treatm en t of th ese fractures, alth ough fixation can be techn ically challenging because of the sm all am ount of bone lateral to th e fracture site. Medial-third fractures generally respond well to nonoperative treatm ent.

Proximal Humerus Fractures Proxim al h um erus fractures accoun t for 4% to 7 % of all fractures and have a bim odal age distribution. In youn g patients, the fractures are a result of high-energy traum a an d often require open reduction an d in tern al fixation (O RIF). Proxim al h um erus fractures are also com m on in elderly patien ts, in wh om th ey occur th rough osteoporotic bon e, often after a fall. In th is patien t population , th ese fractures frequently do well with nonoperative treatm ent. If sign ifican t displacem ent is present, then ORIF or hem iarthroplasty m ay be n ecessary.

Classification Th e m ost useful an d com m on ly used classification of proxim al h um erus fractures is th e Neer classification (Fig. 13.36). The sch em e is based upon dividing th e proxim al hum erus into four segm en ts, as described by Codm an (Fig. 13.37). In order for a segm en t to be con sidered a fracture part, it m ust be displaced at least 1 cm or an gulated 45 degrees. Fractures are th en described based on th e n um ber of parts. In a on e-part fracture, n on e of th e com pon en ts is sufficiently displaced to qualify as a part, regardless of th e n um ber of fracture lin es. Two-part fractures in volve displacem ent of either the articular surface (th rough the an atom ic neck), the entire head (through the surgical neck), the greater tuberosity, or th e lesser tuberosity. In th ree-part fractures, th ere is displacem en t of eith er th e lesser or greater tuberosity, as well as the head through the surgical neck. Four-part fractures in volved displacem en t of

all four segm en ts of th e bon e. Proxim al h um erus fractures can also be associated with dislocations, in which case the direction of th e dislocation an d th e n um ber of parts to th e fracture are described. Wh en usin g th e Neer classification , it is importan t to rem em ber th at th e system was n ot in ten ded as a pure radiograph ic classification system . In stead, it was m ean t to provide a structured way to th in k about th ese com plex fractures an d place th em in to groups with defin ed n atural h istory an d treatm en t option s. Several studies h ave criticized the reproducibility of this classification , but it rem ains the m ost com m on ly used m eth od for describin g th ese fractures. Adequate im agin g, often in volvin g CT scan s, an d in creased rater experience have been shown to improve the accuracy of th e classification .

Mechanism of Injury In th e elderly, th e m ajority of proxim al h um erus fractures are the result of falls onto an outstretched h and. Youn ger patien ts are m ore frequen tly th e victim s of sign ifican t traum a, such as a m otor veh icle collision or a fall from a sign ifican t height. Presentation Th e typical presen tation is th at of pain , swellin g, an d sh oulder deform ity followin g a traum atic in jury. Th e patien t typically holds th e arm at th e side and complains of sign ifican t pain with any m ovem en t of th e sh oulder. If th e fracture is m ore than 6 to 12 h ours old, ecchym oses extending from th e axilla to below th e elbow an d swellin g of th e extrem ity all the way to the h and is not uncom m on. Physical Examination As with all fractures, it is im portan t to m ake sure th at th e overlyin g skin is in tact, alth ough open fractures of th e proxim al h um erus are rare. Given the close proxim ity of the

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Figure 13.36 The Neer classifica-

tion of proximal humerus fractures (see text for detailed explanation). (From Iannotti JP, Williams GR. Disorders of the Shoulder: Diagnosis and Management, 2nd ed. Philadelphia: Lippincott Williams & Wilkins, 2007, with permission.)

axillary artery to th e proxim al h um erus, it is importan t to ch eck distal pulses in th e extrem ity. It is possible to h ave an in tact radial pulse in th e presen ce of a vascular in jury, so any evidence of an expandin g hem atom a should be fur-

ther investigated with an arteriogram . Neurologic injuries are not uncom m on followin g th ese in juries, so it is im portan t to perform an d docum en t a th orough n eurologic exam in ation . Th e axillary n erve is particularly at risk as it courses inferiorly below the subscapularis and th rough the quadran gular space (Fig. 13.16). Sensation over the lateral aspect of th e upper arm is not an accurate indicator of axillary nerve function. Alth ough pain will likely prevent the patien t from actually abductin g th e arm , it is im portan t to evaluate th e axillary n erve by ch eckin g for deltoid m uscle activation with attempted abduction of th e arm .

Radiographic Examination Radiograph ic evaluation m ust in clude an AP view of th e GH join t, a scapular Y view, an d an axillary lateral view. Th e axillary view is especially importan t in evaluatin g for the presence of a dislocation of the GH joint. Figure 13.37 The Neer classification is based on dividing the

proximal humerus into four segments, as described by Codman. (From Chapman MW, Szabo RM, Marder RA, et al. Chapman’s Orthopaedic Surgery. Philadelphia: Lippincott Williams & Wilkins, 2001, with permission.)

Special Tests Even experien ced clin ician s can h ave difficulty describing th e exact fracture pattern based on plain radiographs. In m ost displaced fractures, CT scan s are useful to better


A

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B Figure 13.38 A: Anterior-posterior radiograph demonstrating a three-part fracture of the proxi-

mal humerus. The fracture lines separate the greater tuberosity, humeral shaft, and head fragment. The lesser tuberosity remains attached to the head fragment. B: Open reduction and internal fixation was obtained using a plate and screws. (From Chapman MW, Szabo RM, Marder RA, et al. Chapman’s Orthopaedic Surgery. Philadelphia: Lippincott Williams & Wilkins, 2001, with permission.)

visualize and understand the injury pattern and aid in treatm en t decision m aking. For patients with neurologic deficits or th ose with an un expectedly prolon ged recovery, n eurodiagn ostic testin g is valuable in detectin g an d classifyin g neurologic injury.

Differential Diagnosis Th e differen tial diagn osis in cludes oth er traum atic in juries to th e sh oulder region . In th e patien t wh o presen ts with con siderable sh oulder pain followin g a fall, but h as negative radiograph s, con sideration sh ould be given to a nondisplaced proxim al hum eral fracture or acute rotator cuff tear. Both entities can be seen on an MRI scan. Treatment Greater th an 70% of proxim al h um erus fractures are nondisplaced and do well with nonoperative treatm en t con sisting of 4 to 6 weeks of im m obilization in a sling. Given th e in tra-articular n ature of th e in jury, stiffn ess is a significant concern. If the fracture pieces m ove as a sin gle un it with m otion of th e arm , th e patien t is asked to rem ove his sling several tim es a day and perform gen tle pen dulum exercises. Un stable fractures sh ould be reevaluated weekly an d started on m otion exercises as soon as the pieces m ove as a unit. Two-part and som e three-part fractures with out significant displacem en t, especially in elderly patien ts, can

be treated n on operatively, as described earlier. For fractures with sign ifican t displacem en t, especially in youn ger, h igher-dem an d patien ts, operative fixation usin g a variety of fixation tech n iques is preferred. Alth ough several tech n iques h ave been described, th e goal of surgery is always to ach ieve an an atom ic reduction with en ough stability to perm it early m otion (Fig. 13.38). In four-part fractures, avascular n ecrosis is a particular concern because the fragm ent containing the articular surface is generally separated from its soft tissue attachm ents an d blood supply. In youn ger patien ts, attempts at ORIF sh ould be m ade wh en possible, wh ereas older individuals are gen erally treated with h em iarth roplasty. Alth ough h em iarthroplasty for th e treatm en t of proxim al hum erus fractures is often effective in relieving patients’ pain, function al results are h igh ly variable, with a sign ifican t n um ber of patien ts failin g to ach ieve m ore th an 90 degrees of forward elevation .

Acromioclavicular Joint Sprains In jury to th e AC join t is a frequen t cause of sh oulder pain , especially in youn ger patien ts participatin g in ath letic activities. Sprains of the AC joint result in varying disruption of the supporting structures between th e distal clavicle and proxim al acrom ion, leading to separation of th e joint surfaces—which is why this entity is also referred to as a “sh oulder separation .’’

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Classification Sprain s of th e AC join t are classified based on th e degree of ligam en t disruption an d th e am oun t an d direction of clavicular displacem ent, as described by Rockwood (Fig. 13.39). Type I in juries are a sprain of th e AC ligam en t with no displacem ent of the joint. In type II injuries, the AC

ligam ents are torn and th ere is a sprain of the CC ligam ents. Type III sprain s in volve disruption of both th e AC an d CC ligam ents, with up to 100% superior displacem ent of the distal clavicle from th e acrom ial join t surface. Separation types IV through VI involve complete disruption of the AC and CC ligam ents and wide displacem ent of the clavicle.

Type II

Type I

Type IV

Type III

Conjoined tendon of biceps and coracobrachialis

Type V

Type VI

Figure 13.39 A: The Rockwood classification of injuries to the acromioclavicular joint (see text for detail explanation). (From Bucholz RW, Heckman JD, Court-Brown C, et al. Rockwood and Green’s Fractures in Adults, 6th ed. Philadelphia: Lippincott Williams & Wilkins, 2006, with permission.)


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in juries, it sh ould localize to th e AC join t. Exam in ation of the SC joint, clavicle, and GH joint is important to rule out any associated in juries.

Radiographic Examination An AP view an d axillary lateral are n eeded for evaluation of AC joint traum a. The Zanca view is preferred over a standard AP radiograph . Th is view is obtain ed by an glin g th e x-ray beam 10 degrees toward th e h ead an d decreasin g th e kV by h alf in order to better visualize th e AC join t (Fig. 13.34). Alth ough th is view will dem on strate step-off at th e AC join t, th e degree of superior displacem en t of th e distal clavicle can best be described by comparin g th e CC distan ce in each sh oulder. In type III sprain s, th is distan ce is typically increased 25% to 100%, whereas in type V injuries it is increased 100% to 300%. The axillary view is important for rulin g out an associated GH dislocation an d posterior displacem en t of th e clavicle, as seen in type IV in juries.

Figure 13.40 The most common mechanism of injury to the acromioclavicular joint is a direct force from a fall on the tip of the shoulder. (From Buholz RW, Heckman JD, Court-Brown CM. Rock-wood and Green’s Fractures in Adults, 6th ed. Philadelphia: Lippincott Williams & Wilkins, 2006, with permission.)

In type IV, th e displacem en t is posterior; in type V it is superior, and in type VI th e clavicle is displaced inferior to the coracoid process.

Mechanism of Injury Acrom ioclavicular injury is the result of direct traum a to the lateral aspect of shoulder. Most com m on ly, this occurs as a fall onto the tip of the shoulder during a sporting activity (Fig. 13.40). The traum atic load applies an in feriorly directed force on th e acrom ion relative to th e clavicle. Depen din g on th e degree of th e force, th ere is progressive disruption first of th e AC ligam en ts an d th en of th e CC ligam ents. Presentation Patients with acute AC sprains present with pain localized to th e AC join t followin g direct traum a to th e sh oulder. Occasion ally, these patients will present in a delayed m anner, in which case they m ay have m ilder symptom s over the AC joints accompanied by fatigue and cramping around the sh oulder and scapula worsened by overh ead activity. Physical Examination Patients with AC joint injuries will typically have pain an d ten dern ess directly over th e AC join t. With in creased severity of injury, there will also be in creased step-off and deform ity across the joint. Although pain is often present with active m otion of the shoulder, especially with higher-grade

Special Tests No special tests are n ecessary for th e evaluation of AC in juries. If th ere is question as to th e degree of separation , stress views can be obtained by takin g Zanca views of each sh oulder with 5 to 10 pounds of weight suspended from each wrist. In type II separation s, th e CC distan ce sh ould rem ain unchan ged, whereas type III sprains will dem on strate an increase in the distance from the additional stress caused by the weights. Clinically, stress views are rarely needed because if a type III separation is n ot apparen t on stan dard radiograph s, it is likely to respon d well to con servative treatm ent. Differential Diagnosis Acrom ioclavicular join t sprain s m ust be distin guish ed from distal clavicle fractures, wh ich can be accom plish ed with radiograph s. Degen erative con dition s of th e distal clavicle, such as AC join t arth ritis and distal clavicle osteolysis, can also cause pain over the AC joint. These conditions have a m ore insidious onset and lack both the characteristic isolated traum atic even t to the lateral shoulder, as well as an increase in the CC distance on plain film . Treatment Th e in itial treatm en t for all AC join t in juries is supportive care with the use of a slin g, ice, and nonsteroidal antiinflam m atory drugs (NSAIDs). Type I an d II injuries are treated conservatively, with a gradual return to activity as sym ptom s decrease. Ath letes with type I injuries will generally be able to return to th eir sport with in a few days, wh ereas type II in juries often require several weeks before a substantial improvem ent in symptom s occurs. Th e treatm en t for type III in juries is con troversial. Th e m ajority of patien ts do well with conservative treatm en t. It is important to advise patients that the step-off across the

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articular surface will result in a lastin g cosm etic deform ity but th e pain gen erally resolves with a correspon din g return in sh oulder fun ction . Return to ath letic activity m ay take several m onths. Operative treatm en t is reserved for patients who fail conservative m easures. Th ese patien ts will often complain of fatigue of the shoulder and pain about the an terior trapezius. Man ual laborers an d overh ead ath letes with injury to th eir dom in ant arm s are can didates for acute repair, alth ough surgery will often result in a prolon ged absen ce from work or ath letic activity wh en compared to conservative treatm ent. A vast array of surgical techn iques to repair th e CC ligam en ts h ave been described; often th e AC ligam en t is detach ed from th e en d of th e acrom ion an d tran sferred to th e distal clavicle (Weaver-Dun n procedure) or an allograft h am strin g ten don is used. Type IV to VI separations are treated with early surgical reconstruction .

Glenohumeral Instability As previously m ention ed, the shoulder h as the largest ROM of any join t in th e body. Un fortun ately, th is m obility com es at th e expen se of stability: Th e GH join t is also th e m ost frequen tly dislocated m ajor join t. Wh en discussin g in stability of th e GH join t, it is importan t to keep th e defin ition of four key term s in m in d. Laxity is asymptom atic tran slation of th e h um eral h ead on th e glen oid. Laxity is required for norm al GH m otion, h as a large variation between individuals, an d ten ds to decrease with in creasin g age. Instability is a path ologic con dition ch aracterized by pain associated with excessive tran slation of th e h um eral h ead on th e glen oid. If th e in stability leads to complete separation of th e articular surfaces, it is referred to as a dislocation. Typically, a reduction m an euver perform ed by th e patien t or an oth er in dividual is required to restore th e alignm en t of th e joint. Wh en th e in creased tran slation of th e h um eral h ead results in partial separation of the articular surfaces, and th e GH relation sh ip spon tan eously return s to n orm al followin g rem oval of th e deform ing force, the even t is term ed a subluxation.

Classification Several factors m ust be con sidered wh en classifyin g GH in stability, th e m ost importan t of wh ich is presen ce of a traum atic even t leadin g to th e in itial episode of in stability. Th om as an d Matsen divided GH in stability in to two broad categories with th e m n em on ics TUBS an d AMBRI. Traumatic unidirectional Bankart surgery (TUBS) refers to th e fact th at traum atic in stability of th e sh oulder is gen erally un idirection al, associated with a Ban kart lesion s (see th e section Mechanism of Injury), an d respon ds well to surgical treatm ent. Atraumatic multidirectional bilateral rehabilitation inferior capsular shift (AMBRI) describes atraum atic in stability th at ten ds to occur bilaterally an d respon ds to reh abilitation , or if th at fails, an in ferior capsular sh ift. Although these m n em onics oversimplify this complex con-

TABLE 13.3

SHOULDER INSTABILITY CLASSIFICATION I. Degree A. Dislocation B. Subluxation C. Subtle II. Frequency A. Acute (primary) B. Chronic 1. Recurrent 2. Fixed III. Etiology A. Traumatic (macrotrauma) B. Atraumatic 1. Voluntary (muscular) 2. Involuntary (positional) C. Acquired (microtrauma) D. Congenital E. Neuromuscular (Erb palsy, cerebral palsy, seizures) IV. Direction A. Unidirectional 1. Anterior 2. Posterior 3. Inferior B. Bidirectional 1. Anteroinferior 2. Posteroinferior C. Multidirectional

dition , th ey provide an excellen t fram ework for th in kin g about shoulder instability. Curren t classification of GH in stability in volves th e description of th e direction , etiology, frequency, degree, and volitional control of the instability (Table 13.3). Unidirectional instability can be either anterior, posterior, or in ferior, with an terior bein g th e m ost com m on . Multidirectional instability always in cludes in ferior in stability com bin ed with eith er an terior, posterior, or an terior an d posterior in stability. Th e etiology of th e in stability is traum atic, atraum atic, or congenital. Frequency is important in determ inin g the impact of the instability on th e patien t’s life. Degree of in stability is described usin g th e term s dislocation, subluxation, an d subtle (m eaning th e patient experien ces pain with out in stability, an d th e physician is able to reproduce th e patien t’s symptom s by tran slatin g th e h um eral h ead on physical exam in ation ). Fin ally, any volun tary com pon en t to th e in stability m ust be described. A subset of patien ts will volun tarily dislocate or sublux their sh oulders because of em otional disorders associated with secon dary gain . These patien ts do extrem ely poorly with orth opaedic in terven tion an d are better addressed by psych iatric evaluation. It is important to distinguish these patien ts from a secon d group of patien ts wh o are able to recreate th eir in stability by selective m uscle con traction an d position of th e arm but attem pt n ot do so except wh en being exam ined by a physician.


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ducted, an d in tern ally rotated arm . Posterior dislocation s can also occur following sudden m uscle contractions associated with seizures an d electrical shocks. As the nam e implies, atraum atic in stability occurs with out an teceden t traum a. It is m ore com m on ly m ultidirection al an d often occurs in patien ts with hyperlaxity of th eir join ts. A second group of patients who are prone to atraum atic in stability are th ose in volved in sports th at place sign ifican t stress on the capsular restraints that lim it shoulder m obility, such as overh ead th rowers, gym n asts, an d swim m ers. Th e instability in th ese ath letes is n ot truly atraum atic; in stead, it develops as a result of m icrotraum a that occurs with th e repetitive stretch ing of the capsule and ligam ents durin g participation in th ese sports.

Figure 13.41 Illustration of a Bankart lesion involving a tear of the anterior inferior labrum off the glenoid rim. (From Johnson DH, Pedowitz RA. Practical Orthopaedic Sports Medicine and Arthroscopy. Philadelphia: Lippincott Williams & Wilkins, 2007, with permission.)

Mechanism of Injury A traum atic blow to a m axim ally abducted, externally rotated arm is th e m ost com m on m ech an ism of in jury for an acute anterior shoulder dislocation. With the arm in this provocative position , GH stability is provided prim arily by the anterior ban d of th e in ferior glenohum eral ligam ent (AIGHL). Further external rotation of th e arm , an anterior directed force applied to th e posterior sh oulder, or a posterior force directed toward th e h an d or elbow levers th e hum eral head away from the glenoid an d results in an an terior dislocation . Th ese in juries frequen tly occur durin g a wide variety of ath letic activities an d are m ore com m on in m ales than fem ales. Th e an terior dislocation of th e h um eral h ead results in the disruption of th e anterior stabilizin g structures, especially th e AIGHL an d an terior in ferior glen oid labrum . Th is was classically described as an avulsion of th ese structures from the anterior inferior glenoid rim and term ed the Bankart lesion (Fig. 13.41). It is n ow clear th at th ese restrain in g structures can fail anywh ere alon g th eir len gth , in cluding at th e glenoid rim (Bankart lesion), as a m idsubstance rupture or stretch, an d at their hum eral attachm en t (referred to as a hum eral avulsion of the glenohum eral ligam en t or HAGL lesion ). Con traction of th e sh oulder girdle m usculature on ce th e h um eral h ead h as slipped forward over th e glen oid rim can lead to an impaction fracture of the posterior lateral h um eral head, called a Hill-Sachs lesion (Fig. 13.42). Acute posterior instability typically occurs following a posteriorly directed force tran sm itted th rough a flexed, ad-

Presentation Patien ts with acute dislocation s will presen t with a sudden on set of pain an d deform ity of th e sh oulder followin g a traum atic event. The patient will keep the arm splinted at th e side, often supportin g th e wrist with th e opposite h an d. Any rotation th rough th e GH join t will lead to severe pain . Wh en recurren t, th e sh oulder m ay dislocate with little or no traum a and, especially as th e capsular structures are stretched with an increasing num ber of dislocations, th e patien t is often able to relocate th e join t with out assistan ce. In these patien ts, it is important to determ in e th e n ature of th e in jury at th e tim e of th e first dislocation, h ow it was initially treated, th e num ber of recurrences, and the specific activities or positions that now cause instability. Patients with subluxation or m ultidirectional instability will presen t with complain ts of pain wh en th e join t sh ifts out of place with provocative position in g of th e arm . In athletes with subtle instability, the presenting complaint is often sh oulder pain an d a decrease in ath letic perform an ce. Th is pain often occurs on ly wh en th ey are participatin g in athletics and m ay or m ay not be associated with a sensation of in stability or loss of stren gth in th e arm . Physical Examination With an acute anterior dislocation, prom inence of the h um eral h ead an teriorly will be presen t, with n oticeable flatten ing of the n orm al roun ded con tour of th e posterior sh oulder. The sh oulder is globally pain ful and prereduction exam in ation is gen erally lim ited to th e assessm en t of th e n eurovascular status. As with proxim al h um erus fractures, th e axillary n erve is at particular risk for in jury with sh oulder dislocation , as it passes alon g th e in ferior sh oulder capsule to transverse th e quadrangular space (Fig. 13.16). Assessm en t an d docum en tation of deltoid m uscle m otor function is important prior to attempting any reduction m aneuvers. With posterior dislocation s, th e arm will be h eld in tern ally rotated at th e side, an d any attem pts at external rotation will cause sign ifican t pain . Th ere m ay be som e an terior flatten in g an d posterior prom in en ce alth ough th is is often difficult to appreciate because of the increased

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A

B Figure 13.42 Impaction of the posterior superior humeral head on the glenoid rim leads to a Hill-Sachs lesion of the humeral head. A: An axillary radiograph demonstrating an anterior dislocation with a Hill-Sachs lesion. B: A post-reduction computed tomography scan further demonstrating the impaction fracture. (From Iannotti JP, Williams GR. Disorders of the Shoulder: Diagnosis and Management, 2nd ed. Philadelphia: Lippincott Williams & Wilkins, 2007, with permission.)

bulk of th e posterior sh oulder. Th ere is a h igh in ciden ce of m issed posterior dislocation of th e sh oulder, often with disastrous con sequen ces. For th is reason , any patien t experien cin g traum a to th e upper extrem ity, a seizure, or an electrical sh ock an d decreased extern al rotation of th e GH join t sh ould be suspected of h avin g a posterior dislocation un til proven oth erwise by axillary radiograph s. Patients presenting for evaluation of recurrent or atraum atic in stability sh ould un dergo a stan dard physical exam in ation of th e sh oulder in cludin g RO M an d stren gth testin g. Several specific tests h ave been developed to assess GH laxity an d in stability by assessin g pain an d appreh en sion with provocative positioning of the arm . Anterior in stability is evaluated via th e apprehen sion test. The patien t is placed in th e supin e position to stabilize th e scapula, an d th e elbow is flexed 90 degree wh ile th e sh oulder is abducted 90 degrees (Fig. 13.43). Th e exam in er th en slowly extern ally rotates th e arm . A positive test occurs wh en th e patien t experien ces appreh en sion of im pen din g in stability. Th is is followed by th e relocation test, in wh ich th e exam -

iner uses his opposite hand to place a posteriorly directed force on th e hum eral head. For a positive test, the patient’s apprehension is relieved by the posteriorly directed force. Posterior in stability is assessed by applying a posteriorly directed force to th e arm with th e sh oulder adducted, in tern ally rotated, an d flexed 90 degrees. A positive test is in dicated by pain with posterior subluxation of th e h um eral h ead. These m an euvers sh ould be carried out with great care or skipped altogeth er in patien ts with a recen t dislocation. In a patient with a clear history of dislocation, there is n o need to con firm instability by dislocatin g th e patient’s join t durin g th e office exam in ation , as th is will lead to an extrem ely un com fortable experien ce for both patien t an d physician . Anterior/ posterior laxity of the GH joint is evaluated with th e load an d sh ift test, wh ich can be don e in both th e uprigh t an d supin e position s. For th e supin e test, th e exam in er position s th e patien t’s arm in th e plan e of th e scapula, at 45 to 60 degrees of abduction and neutral rotation . Th e exam in er th e places h is opposite h an d aroun d


A

531

B Figure 13.43 The apprehension (A) and relocation (B) tests for anterior instability. (From Ian-

notti JP, Williams GR. Disorders of the Shoulder: Diagnosis and Management, 2nd ed. Philadelphia: Lippincott Williams & Wilkins, 2007, with permission.)

the arm at th e level of the deltoid tuberosity and applies an anterior and then posterior force to the arm while com pressin g th e GH join t. Laxity is graded based on direction an d the am ount of translation of the hum eral h ead from grade 0 (m in im al m ovem en t) to grade 3 (dislocation of th e hum eral head) (Fig. 13.44). In ferior laxity is evaluated by th e sulcus sign . With th e elbow flexed 90 degrees an d adducted to th e side, an in ferior force is applied to th e arm . Th e distan ce between th e acrom ion and hum eral h ead is then observed and m easured in centim eters (Fig. 13.45). Greater th an 2 cm of inferior translation is indicative of inferior laxity.

Radiographs Any patien t with a possible sh oulder dislocation sh ould be evaluated with AP, scapular Y, an d axillary radiograph s. O f th e th ree views, th e axillary lateral is by far th e m ost im portan t. Radiology tech n ologists will often sh oot a th ree-view sh oulder series consisting of an AP in in ternal and extern al

Figure 13.44 Laxity of the glenohumeral joint is evaluated with

Figure 13.45 A positive sulcus sign indicating inferior laxity.

the load and shift test. (From Iannotti JP, Williams GR. Disorders of the Shoulder: Diagnosis and Management, 2nd ed. Philadelphia: Lippincott Williams & Wilkins, 2007, with permission.)

(From Krishnan SG, Hawkins RJ, Warren RF. The Shoulder and the Overhead Athlete. Philadelphia: Lippincott Williams & Wilkins, 2004, with permission.)

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or pain an d a physical exam in ation suggestive of in stability, MRI scannin g is a useful tool. Th is study can be used to evaluate th e soft tissue restrain ts to in stability an d also to rule out other path ologic conditions about the shoulder. Th e use of in tra-articular con trast to obtain an MRI arth rogram in creases th e accuracy in evaluatin g in th e labrum and capsular structures.

Differential Diagnosis Th e differen tial diagn osis of acute sh oulder dislocation s in patien ts with severe pain after traum a injury includes AC separations and fractures about the shoulder complex. Th ese can be easily distin guish ed by physical an d radiograph ic exam in ation . For patien ts, especially ath letes, with subtle in stability presen tin g prim arily as pain , th e differen tial diagn osis in cludes several other shoulder disorders such as rotator cuff path ology, SLAP tears, AC join t arth ritis, an d scapuloth oracic m otion abn orm alities.

Figure 13.46 The Velpeau view is obtained by having the pa-

tient lean backward 30 degrees over the cassette with his arm in the sling. The beam is then directed superior to inferior through the shoulder. This view provides a magnified axillary view in patients who cannot tolerate abduction of the arm. (From Iannotti JP, Williams GR. Disorders of the Shoulder: Diagnosis and Management, 2nd ed. Philadelphia: Lippincott Williams & Wilkins, 2007, with permission.)

Treatment Followin g clin ical an d x-ray evaluation , th e in itial treatm en t for acute anterior dislocations involves closed reduction under con scious sedation. This can be accomplish ed by a variety of m an euvers that gen erally involve traction – coun ter traction across the joint (Fig. 13.47). Following reduction , th e arm is placed in a slin g, th e n eurovascular status is rechecked, and postm anipulation film s are obtain ed to con firm th e reduction .

rotation an d a scapular Y. Alth ough it is often possible to detect a dislocation on th e Y view, it is also easy to m iss a dislocation , especially if th e beam is n ot exactly parallel to th e scapula. Th e axillary view will clearly dem on strate any an terior or posterior tran slation of th e h um eral h ead on th e glen oid an d is m an datory in th ese patien ts. If th e patien t can n ot tolerate abduction of th e arm for an axillary view, th e Velpeau view can be obtain ed with out rem ovin g the patien t’s arm from the sling (Fig. 13.46). A num ber of special x-ray views h ave been described to detect various path ologies th at can accompany sh oulder in stability; however, these views h ave generally been replaced by the widespread use of CT an d MRI scans.

Special Studies Followin g a sim ple dislocation an d reduction , n o addition al studies are n eeded if n o bon ey abn orm alities are suspected on the pre- an d postreduction radiograph s. If there is concern regardin g the size of Hill-Sachs lesions or bon e defects about th e an terior glen oid rim , th en a CT scan is useful. For patien ts with an un clear h istory of in stability

Figure 13.47 The most commonly used technique for reduction

of an anterior shoulder dislocation uses a sheet around the axilla to provide a counter-traction force. A longitudinal force is then applied to the arm to disengage the humeral head from the anterior glenoid rim and allow it to return to the articular surface. (From Buholz RW, Heckman JD, Court-Brown CM. Rockwood and Green’s Fractures in Adults, 6th ed. Philadelphia: Lippincott Williams & Wilkins, 2006, with permission.)


Tradition ally, th e arm h as been m ain tain ed in a slin g in internal rotation for a period ranging from several days to several weeks. This h as led to a high recurrence rate in younger patients (between 50% and 90% in patients under th e age of 20). Recen t eviden ce suggests th at im m obilization in 10 degrees of extern al rotation for 3 weeks can significan tly decrease the recurren ce rate in patients un der th e age of 30. Followin g im m obilization , th e patien t is started on a physical therapy program to regain m otion and strengthen the dynam ic stabilizers of th e sh oulder and is perm itted a gradual return to activity. Most surgeon s reserve operative treatm en t for patien ts with recurren t in stability. After th e secon d dislocation , th e patien t is un likely to rem ain stable un less h e is willin g to significan tly m odify h is activity. Operative treatm en t con sists of either open or arthroscopic repair of the in jured structures, m ost com m on ly, the anterior in ferior labrum and capsule. Alth ough the early results of arthroscopic treatm ent were inferior to open repair, advances in arthroscopic techniques have led to success rates of greater than 90% in m ore recen t series. Th e two exception s to an in itial trial of non operative treatm ent for first tim e dislocators are (a) high-level athletes for whom a second dislocation would result in th e loss of an addition al season of play an d (b) in dividuals involved in activities in which a recurren t dislocation could com prom ise th eir overall safety. In patien ts over th e age of 40, th e risk of recurren t in stability is less than the risk of stiffness. Im m obilization in th is age group is for patien t com fort on ly, an d RO M exercises are begun as soon as th e patien t tolerates m ovem en t. Th ese patien ts are at a m uch h igh er risk of rotator cuff tears or neurologic in juries followin g dislocation . Any weakn ess persistin g m ore th an a week or two after th e dislocation sh ould be furth er investigated with an MRI scan an d possibly a nerve conduction study (NCS)/ EMG. Acute posterior dislocations should be reduced un der conscious sedation . Followin g reduction , th e GH join t m ay be un stable wh en placed in a slin g. If th is is th e case, th e arm should be held in neutral or extern al rotation using a specially designed sling or sh oulder spica cast. If th e diagnosis of a posterior dislocation h as been delayed for m ore th an a few days, reduction requires gen eral an esth esia in th e operatin g room an d often m ust be don e in an open m anner. In the absence of boney injuries, recurren t posterior in stability is less com m on th an an terior in stability. When surgery is required, posterior capsular repair or placation is m ore easily accom plish ed via arth roscopic rath er th an open tech n iques. Th e first lin e of treatm en t for atraum atic an d m ultidirection al in stability is physical th erapy to stren gth en th e rotator cuff m uscles an d scapuloth oracic stabilizers. If th e instability persists despite 3 to 12 m on th s of therapy, th en th e patien t m ay be a can didate for operative m an agem en t. Surgical treatm ent involves either an open or arthroscopic procedure to reduce th e capsular volum e; h owever, th e results of surgical treatm ent are n ot as predictable as th ey are

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for traum atic instability. Operative intervention in athletes with subtle in stability is difficult because the procedure n eeds to decrease th e patien t’s laxity en ough to elim inate h is in stability wh ile m ain tain in g en ough m otion for the patien t to con tin ue participation in h is sport.

Superior Labrum Anterior to Posterior (SLAP) Lesions Since th e increase in use of shoulder arthroscopy in th e 1980s an d 1990s, SLAP lesion s h ave been recogn ized as a source of intra-articular shoulder pain in patients under th e age of 40. Th ese in juries in volve th e superior glen oid labrum and th e insertion of the long head of the biceps ten don on to th e supraglen oid tubercle.

Classification Superior labrum an terior to posterior tears were originally described by An drews in 1985, an d furth er defin ed an d classified in to four types by Snyder in 1990 (Fig. 13.48). Type I tears in volve frayin g or degen eration of th e superior labrum without detachm ent of the labrum or the biceps anchor. In type II tears, there is detachm en t of the superior labrum an d biceps an ch or from th e glen oid rim . Type III tears are ch aracterized by a “bucket-h an dle tear’’ of a portion of th e superior labrum , with th e rem ain in g superior labrum an d biceps an ch or still firm ly attach ed to th e glenoid rim . The type IV SLAP involves a “bucket-h andle tear’’ of th e superior labrum th at exten ds in to th e biceps ten don . Sin ce Snyder’s origin al classification , several addition al types of SLAP tears h ave been described. Th ese involve exten sion of the tear into varying portions of the anterior or posterior labrum and m ay be associated with sh oulder in stability. Mechanism of Injury Superior labrum an terior to posterior lesions are typically caused by traction or com pression in juries to th e sh oulder. Th e m ost com m on m ech an ism is a fall on an abducted, forwardly flexed arm , which leads to a direct compressive force on the superior labrum . Reflex contraction of the biceps m uscle m ay provide addition al traction on th e biceps anchor durin g the fall. Superior labrum an terior to posterior tears are frequen tly foun d to occur in overh ead ath letes. In th ese patients, it is believed that the lesions are due to m icrotraum a from repeated traction transm itted through the biceps tendon durin g th e th rowin g m otion . Th is population also ten ds to h ave hypertrophy of th eir posterior in ferior capsular structures, which causes a posterior superior shift of th e con tact poin t between th e h um eral h ead an d glen oid wh en th e arm is placed in abduction an d extern al rotation (as in the late cockin g phase of the throwing m otion ). This sh ift can lead to dam aging sh eer and compressive forces across the superior labrum .

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A

B

Figure 13.48 The classification of supe-

C

Presentation Th e presen tation of patien ts with SLAP lesion s can be quite variable, and the diagnosis should be considered in all patien ts youn ger th at 40 with pain com in g from with in th e sh oulder joint. The m ost com m on presentation is a youn g, active patien t with activity-related pain deep with in th e sh oulder following a traum atic even t. Th e inciting injury typically in volves a fall on an outstretch ed h an d, weigh t liftin g, autom obile acciden ts, or traction on th e exten ded arm . In overh ead ath letes, rarely is a sin gle traum atic even t the cause; rather, the player will complain of shoulder pain an d a loss of stren gth an d power with th rowin g or overh ead activities. Physical Examination Patien ts with SLAP lesions will typically have full ran ge of m otion an d good stren gth about th e sh oulder, especially of the rotator cuff m uscles. The exception is overhead athletes

D

rior labrum anterior to posterior lesions. (A) Type I. (B) Type II. (C) Type III. (D) Type IV. (From Iannotti JP, Williams GR. Disorders of the Shoulder: Diagnosis and Management, 2nd ed. Philadelphia: Lippincott Williams & Wilkins, 2007, with permission.)

with hypertrophy of th e in ferior capsule. Th ey will h ave a decrease in in tern al rotation with th e arm at 90 degrees of abduction. A large array of special tests h as been described to aid in th e diagn osis of SLAP tears. Un fortun ately, n on e of th em of h as been foun d to be particularly sen sitive or specific. Th ree m an euvers th at we h ave foun d useful are th e O’Brien test, th e Mayo sh eer test, an d th e appreh en sion test. For th e O’Brien test (Fig. 13.49), also known as th e active biceps com pression test, th e patien t places th e arm in 90 degrees of forward flexion , 20 degrees of adduction , an d active, full intern al rotation (thum b points toward floor). The exam in er th en provides a down ward force on th e patien t’s forearm as the patien t raises his arm toward the ceiling. If th is reproduces th e patien t’s pain , th e patien t is asked to full externally rotate the arm (thum b pointing toward th e ceilin g), an d th e down ward force is reapplied. For a positive test, th e pain experien ced with th e arm in in tern al rotation


535

Figure 13.49 O’Brien test for the detection of superior labrum

anterior to posterior tears. For a positive test, the patient will have pain when resistance is applied to the internally rotated arm that is not present when resistance is applied to the externally rotated arm. (From Krishnan SG, Hawkins RJ, Warren RF. The Shoulder and the Overhead Athlete. Philadelphia: Lippincott Williams & Wilkins, 2004, with permission.)

m ust be relieved or dram atically lessened with external rotation . In th e Mayo sh eer test (also kn own as th e dyn am ic labral sh eer test), the patient’s elbow is placed at h is side an d flexed 90 degrees. The exam iner then puts the arm in m axim al passive extern al rotation and gradually abducts the arm wh ile stabilizin g th e patien t’s posterior scapula with th e opposite h an d. A patien t with a positive test will experien ce pain with abduction between 60 an d 120 degrees. A positive test m ay include pain, pain and a click, or simply a click. Although appreh ension testin g is classically used to diagnose an terior shoulder instability, patien ts with SLAP tears will often h ave pain with out a sen sation of in stability wh en th e arm is placed in th e abducted, extern ally rotated position . Th is test is m ost easily perform ed with th e patien t supine on the exam ination table to stabilize th e scapula. For a positive test, th e patien t’s pain sh ould be relieved wh en a posteriorly directed force is applied to th e proxim al hum erus.

Radiographic Findings Stan dard radiograph s are un rem arkable in patien ts with a SLAP tear. Special Studies Magn etic resonance im aging is th e m ost useful im aging m odality for the diagnosis of labral pathology. Th e diagnosis is m ade when fluid is visualized between th e superior glen oid rim an d th e labrum on th e oblique coron al im ages (Fig. 13.50). The specificity and sensitivity of MRI in detecting SLAP tears can be m arkedly improved th rough the use of an MRI arthrogram , wh ich involves the injection

Figure 13.50 Coronal oblique magnetic resonance image

arthrogram demonstrating a superior labrum anterior to posterior tear (big arrow). (From Magee T, Willams, D, Mani N, Shoulder MR arthography: which patient group benefits most? AM J Roentgol 2004:183:969–970, with permission.)

of con trast m aterial in to th e GH join t prior to th e MRI exam ination. Magnetic resonan ce im aging is also useful for identifying other path ology, such as partial articular-sided rotator cuff tears an d Ban kart lesion s th at can lead to sh oulder pain in youn ger patien ts.

Differential Diagnosis Th e differen tial diagn osis for SLAP tears in cludes any en tity that can cause shoulder pain in young patients. For patien ts wh o h ave experien ced a compression or traction injury to the shoulder, GH instability, AC joint injuries, rotator cuff tears, bursitis, an d adh esive capsulitis m ust be excluded based on h istory, physical exam in ation , an d im aging studies. In overhead ath letes, subtle anterior instability, articular-sided rotator cuff tears, and isolated deficits of GH internal rotation can lead to a loss of stren gth and perform ance and m ust be differentiated from SLAP tears. Patients over th e age of 40 com m on ly h ave som e degen eration or even fran k tearin g of th eir superior labrum th at m ay be an asymptom atic part of n orm al aging. Th erefore, in this population , oth er con dition s, especially rotator cuff– related path ology, are m uch m ore likely to be respon sible for th at patien t’s symptom s. Treatment Superior labrum anterior to posterior tears generally do n ot respon d well to con servative treatm en t. In young

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patien ts with a h istory, physical exam in ation , an d im agin g studies con sistent with a labral tear, surgical in tervention is advised. For patien ts suspected of h avin g a SLAP tear, but with out th e m ajority of ch aracteristic fin din g on h istory an d physical exam in ation , a trial of physical th erapy is warran ted. Several of th e con dition s th at can presen t in a sim ilar m anner will often respond well to therapy wh ereas those patients with superior labral path ology will not im prove an d m ay even h ave an exacerbation of th eir sym ptom s. The surgical treatm ent of SLAP tears involves arthroscopic fixation or debridem ent. Type I an d III tears are generally treated with debridem en t, wh ereas th e treatm en t of type II an d IV tears con sists of repair of th e labrum back to the glenoid rim using suture anchors. In patien ts over the age of 40, SLAP tears are often en coun tered at th e tim e of arth roscopy for oth er sh oulder path ology (especially rotator cuff path ology). If th e biceps an ch or is stable an d th e biceps ten don is in good con dition , th ese tears sh ould be ign ored. If th ere is in stability of th e biceps an ch or or degen eration of th e ten don , a biceps ten otomy or ten odesis sh ould be considered.

ATRAUMATIC SHOULDER CONDITIONS Rotator Cuff Pathology Rotator cuff path ology is th e m ost com m on atraum atic condition responsible for shoulder pain . The spectrum of disease in cludes subacrom ial bursitis, rotator cuff ten din opathy, an d partial or complete tears of th e rotator cuff. The exact cause of the patien t’s symptom s is often un clear, leading the caregiver, especially the n onorthopaedist, to label any pain associated with th e rotator cuff as impin gem en t syn drom e. In degenerative disease of the rotator cuff, th e supraspin atus tendon is the m ost com m on ly involved tendon , an d th e prevalen ce of ten don tears in creases with in creasin g age. In terestin gly, a large n um ber of th ese tears, especially those that develop gradually, are asymptom atic. Traum atic

injuries can occur in patients of any age, are often associated with significant weakness, and tend to require surgical treatm ent.

Pathophysiology and Classification As the supraspinatus m uscle passes laterally toward its insertion on the greater tuberosity, its ten don travels undern eath th e CA arch com posed of th e un dersurface of the acrom ion, CA ligam ent, an d AC joint (Fig. 13.51). Th e tendon is separated for th e arch by th e subacrom ial bursa, wh ich allows friction less glidin g between th e ten don an d overlyin g structures. Even in th e n onpath ologic state th ere is a decrease in the subacrom ial space with abduction of the arm , leading to som e impingem ent of th e CA arch on the underlyin g tendon and bursa. Any process resultin g in a decrease in th is space can worsen this impingem ent and lead to inflam m ation of the bursa an d disorders within the rotator cuff ten don . Dysfun ction of th e cuff m uscles causing a decrease in th eir ability to keep the hum eral head cen tered on the glenoid durin g m otion of the arm can lead to superior tran slation of th e h um eral h ead an d a decrease in the subacrom ial space. Likewise, th e space can be reduced from above by abn orm al tilt or sh ape of th e overlyin g acrom ion or hypertrophy of the CA ligam en t or AC joint. Two m ain theories attempt to explain the underlyin g cause of rotator cuff path ology. The external theory suggests that the initial pathologic change is caused by external com pression of th e rotator cuff by th e overlyin g structures. Th is compression leads to inflam m ation within th e subacrom ial bursa and degeneration and eventual tearing of the rotat or cufften don s. Th e intrinsic model suggests that the initiatin g even t is degeneration within the rotator cuff tendon s th em selves. Th e degen eration m ay be due to several factors, in cludin g agin g an d decreased vascularity with in the critical area of the tendon. Th e abnorm al rotator cuff is no lon ger able to keep th e hum eral h ead centered on the glenoid, which can lead to superior translation of th e h ead an d worsen in g tendon destruction by subacrom ial impingem ent. In reality, in m ost patients, som e elem ent of

Figure 13.51 As the supraspinatus tendon

passes laterally, it travels through an enclosed space covered by the coracoacromial arch. (From Johnson DH, Pedowitz RA. Practical Orthopaedic Sports Medicine and Arthroscopy. Philadelphia: Lippincott Williams & Wilkins, 2007, with permission.)


both in trin sic an d extrin sic path ology probably occurs in rotator cuff disease. With eith er th eory, on ce th e process begin s, in creased im pin gem en t occurs between th e cuff an d the CA arch, wh ich can lead to further degeneration of the cuff and hypertrophy of th e overlying structures that worsen s th e im pin gem en t.

Presentation Th e m ost com m on presen tation of rotator cuff disease is a late m iddle-aged patien t with th e gradual on set of dull pain over th e an terior lateral sh oulder. Th e pain often radiates to deltoid in sertion on th e lateral arm , awaken s th e patien t from sleep (especially wh en lyin g or rollin g on to the affected side), an d is exacerbated by overhead activities or reach in g beh in d th e back (as wh en puttin g a wallet in the back pocket of pants or h ooking a bra). Alternately, the pain m ay begin followin g in creased use of th e arm , such as paintin g a room or playing several sets of tennis. O ccasion ally, th e pain m ay follow a traum atic even t. Th is is m ore com m on in youn ger patien ts, an d th ese patients are m ore likely to complain of weakness in addition to pain . As described in th e section on GH in stability, it is important to suspect a rotator cuff tear in any patient over the age of 40 with a dislocation of the GH joint. Physical Examination Patients with longstanding rotator cuff tears m ay have atrophy of th e posterior sh oulder over th e supra- or in fraspin atus fossa. They will often have tenderness to palpation about the cuff insertion on the greater tuberosity. With the exception of th ose with full-th ickn ess tears, full active forward elevation is generally norm al, alth ough it is often accompanied with significant discom fort in the impingem ent zon e between 70 an d 120 degrees. It is n ot un com m on for patien ts with cuff path ology to lack several levels of in ternal rotation when m easured with th e arm beh ind the back. Placin g th e arm in th is position in creases th e con tact between th e an terior superior rotator cuff and CA arch and is often provocative of th e patien t’s pain . Th e evaluation of rotator cuff stren gth is especially im portan t in th e exam in ation of patien ts presen tin g with rotator cuff disease. In patien ts with in flam m ation of th e subacrom ial bursa, it can be difficult to distin guish between true weakness and weakn ess secondary to pain, although with proper instruction, m ost patients with an intact cuff are able to m ain tain at least 4+ / 5 stren gth . Significant weakn ess on strength evaluation , especially positive lag signs, belly-press, or lift-off tests, is concerning for complete tears of the cuff tendons. Several addition al tests h ave been described for th e evaluation of rotator cuff path ology. Best kn own for th e n am e of th e exam in er wh o origin ally described th em , th ese tests attempt to reproduce the patient’s symptom s by m anipulating the arm to increase impingem ent within the subacrom ial space. Unfortunately, although sensitive for th e detec-

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tion of cuff path ology, th ey are also positive in a n um ber of oth er con dition s causin g pain about th e sh oulder. In th e Neer impin gem en t sign , th e in volved extrem ity is passively elevated in th e scapular plan e with th e scapula stabilized (Fig. 13.52A). Th e test is positive when the patien t’s pain is reproduced as th e cuff an d bursa are com pressed again st th e CA arch . Th e Hawkin s im pin gem en t sign is tested by passively intern ally rotatin g the arm while h olding it in 90 degrees of forward flexion with th e elbow also h eld in 90 degrees of flexion (Fig. 13.52B). Again , a positive test in volves recreation of th e patien t’s pain . In addition to evaluatin g supraspin atus stren gth , pain with th e Jobe test is in dicative of rotator cuff path ology. Patien ts with subacrom ial bursitis, rotator cuff ten don itis, an d partial-th ickn ess cuff tears will h ave pain with stren gth testin g of the in volved portion of the rotator cuff an d positive im pin gem en t m an euvers, but n o strength deficits. Patien ts with sm all complete tears of the supraspin atus also gen erally present with pain but no or m in im al stren gth deficits. In con trast, patien ts with larger tears of th e rotator cuff will presen t with both pain an d weakn ess on exam ination. Occasionally, a patien t with a large tear will presen t with a ch ief complain t of weakn ess with no or m inim al associated pain.

Radiographic Findings Th e AP radiograph m ay dem on strate sclerosis of th e un dersurface of th e acrom ion an d cyst form ation in the greater tuberosity. In elderly patien ts, it is important to carefully evaluate th e film s for GH an d AC join t arth ritis. With lon gstan ding disease, th e h um eral head m ay be riding superiorly on th e glen oid, with decrease in th e acrom ioh um eral interval. This is an important finding as it indicates a large, and often irreparable, tear of the cuff (Fig. 13.53). Th e axillary view is useful for dem on stratin g abn orm al ossification cen ters with in th e acrom ion . Th ese are kn own as os acromiale and, when present, m ay contribute to pain an d impingem ent. A m odified scapular Yview, called th e outlet view, is used to evaluate th e m orph ology of th e acrom ion an d th e space available un der th e CA arch . Th e radiograph is obtain ed by orien tin g th e beam parallel to th e spin e of th e scapula an d then an gling it 10 to 30 degrees caudally. Biglian i classified the acrom ion according to its shape on th is view. Type I involves a straigh t, sm ooth acrom ion. In a type II acrom ion, there is a gentle inferior curve anteriorly, whereas a type III acrom ion involves an anterior hook (Fig. 13.54). Type III acrom ion are m ore com m on in patients with full-thickn ess tears, but th e exact relation sh ip between acrom ial m orph ology an d rotator cuff disease rem ain s un clear. Special Tests Magnetic resonance im aging scans are the im aging m odality of choice in evaluating disorders of the rotator cuff. Fulland partial-thickness tears are best seen on the T2 weigh ted coron al oblique im ages (Fig. 13.55). Any associated

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B

A Figure 13.52 A: The Neer impingement sign. B: Hawkins impingement test. (From Iannotti JP, Williams GR. Disorders of the Shoulder: Diagnosis and Management, 2nd ed. Philadelphia: Lippincott Williams & Wilkins, 2007, with permission.)

ten don retraction an d atrophy or fatty in filtration of th e cuff m uscles can be appreciated on MRI. Atrophy and fatty in filtration are best seen on th e m ost m edial sagittal oblique im ages an d are im portan t in dicators of th e ch ron icity of full-th ickness cuff tears (Fig. 13.56). It is becom in g in-

Figure 13.53 Loss of the interval between the acromion and

the humeral head indicates a large, full-thickness tear of the rotator cuff. (From Johnson DH, Pedowitz RA. Practical Orthopaedic Sports Medicine and Arthroscopy. Philadelphia: Lippincott Williams & Wilkins, 2007, with permission.)

creasingly clear that when these two processes are present, the chance of tendon healin g following rotator cuff repair is significantly decreased. Ultrasound is also gaining popularity in the evaluation of cuff disease. Wh en compared to MRI, it h as th e advan tage of bein g less expen sive an d better tolerated by patien ts, but it is highly operator-depen den t and less suited to evaluating atrophy and fatty infiltration of the m uscles. It is especially useful in postoperative patien ts, in wh om artifact can m ake the interpretation of MRI scans difficult. For patien ts with con fusin g h istorical an d physical exam in ation findings, the impingem ent injection test is useful for localizing pain to the subacrom ial space. Following exam in ation , th e patien t is in jected with 3 to 5 m L of 1% lidocaine into the subacrom ial space. If this results in the elim in ation of th e patien t’s pain with provocative m an euvers, then it is likely that the pain is associated with pathology with in th e subacrom ial space. Stren gth exam in ation followin g injection also allows for evaluation of m uscle function with out interference from pain.

Differential Diagnosis Th e differen tial diagn osis of rotator cuff disease is agedepen den t. In older patien ts, it in cludes cervical spin e path ology, GH arth ritis, m etastatic disease an d referred sources of sh oulder pain such as cardiac disease. Impingem en t and cuff path ology is m uch less frequent in younger patien ts, an d m ore com m on sources of sh oulder pain


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Figure 13.55 T2 weighted coronal oblique magnetic resonance image demonstrating a full thickness tear (arrows) of the supraspinatus tendon. (From Johnson DH, Pedowitz RA. Practical Orthopaedic Sports Medicine and Arthroscopy. Philadelphia: Lippincott Williams & Wilkins, 2007, with permission.)

Figure 13.54 Acromial morphology as described by Bigliani:

teroid in jection . Alth ough th ere are n o absolute guidelin es regardin g th ese in jection s, con cern s about ten don dam age sh ould lim it th eir use to no m ore than three with at least 3 m on th s in between in jection s in m ost patien ts. It is im portan t to em ph asize to patien ts th at, wh ile th e in jection s

type I, flat; type II, curved; type III, hooked. This is evaluated on the supraspinatus outlet view. (From Iannotti JP, Williams GR. Disorders of the Shoulder: Diagnosis and Management, 2nd ed. Philadelphia: Lippincott Williams & Wilkins, 2007, with permission.)

in this population (such as instability and labral tears) sh ould be con sidered. In any age group, adh esive capsulitis, calcific tendonitis, and AC joint arthritis sh ould be considered.

Treatment Th e treatm en t of rotator cuff disease depen ds on th e path ology an d th e age of th e patien t. If th ere is n o suggestion of a full-th ickn ess cuff tear on th e h istory, physical exam ination, and radiograph s, then th e presumptive diagn osis is cuff ten don itis or bursitis, an d th e in itial treatm en t is nonoperative. At first, this consists of rest and education . Th is is followed by a progressive physical th erapy program to regain m otion, strengthen th e cuff, and restore n orm al scapuloth oracic stren gth an d rhyth m . Specific exercises to strengthen the cuff m uscles help to keep the hum eral head centered in the glenoid during m otion , thereby creating m ore space for the tendons in the subacrom ial space. The speed of the patient’s improvem ent can be enhanced through the use of subacrom ial corticos-

Figure 13.56 T1 weighted sagittal oblique magnetic resonance

image depicting atrophy (arrows) of the supraspinatus muscle. (From Johnson DH, Pedowitz RA. Practical Orthopaedic Sports Medicine and Arthroscopy. Philadelphia: Lippincott Williams & Wilkins, 2007, with permission.)

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will relieve their sym ptom s, th e pain will return un less th e patien t com plies with th e th erapy program . Patients who fail to improve with 2 to 3 m onths of conservative treatm en t should un dergo an MRI scan or ultrasound to evaluate th e structural integrity of th e cuff. Im m ediate im agin g sh ould also be con sidered in patien ts with significant weakn ess or following a traum atic injury. Patien ts with a structurally in tact cuff sh ould con tin ue with an oth er 2 to 3 m on th s of con servative treatm en t. If th ey continue to be symptom atic then arthroscopic or open subacrom ial decompression is effective. For patien ts with full-th ickn ess rotator cuff tears, treatm en t depen ds on th e age of th e patien t an d th e ch ron icity of th e tear. If MRI dem on strates atrophy an d fatty in filtration of th e cuff m uscles, surgical repair is un likely to restore cuff integrity and function, so an extended course of physical th erapy is in dicated. Con tin ued pain can be treated with arthroscopic debridem en t, partial cuff repair an d, in selected cases, m uscle transfers. Patients who are physiologically older and less active with a full-thickness cuff tear but no atrophy and fatty in filtration will gen erally becom e asym ptom atic with physical th erapy. Decision m akin g in th ese patien ts in volves exten sive coun selin g by th e surgeon . If th e patien t opts for nonoperative treatm ent, it is importan t th at he un derstan ds that the tear m ay progress and the m uscles m ay atrophy; therefore if he becom es symptom atic again in the future, repair m ay n o lon ger be an option . On th e oth er h an d, successful surgical treatm ent involves im m obilization followed by an exten ded course of physical th erapy th at th e patien t m ay be un willin g or un able perform . Youn ger, m ore active patients are less likely to be satisfied with n on operative treatm en t an d gen erally ch oose operative in terven tion . Con troversy exists con cern in g asym ptom atic patien ts un der th e age of 50 or 60 wh o presen t with full-thickness tears without m uscle ch an ges. Th ese patien ts are at sign ifican t risk for progression of th eir tear an d a return of symptom s in th e future. It is importan t to discuss th is with th e patien t wh en con siderin g operative versus n on operative treatm en t. Acute tears of th e rotator cuff that result from traum a are m ore likely to be associated with sign ifican t weakness, as the rem ain in g cuff m uscles do not have tim e to adapt an d compen sate. Because th ese patien ts are often youn ger an d do n ot h ave degen erative ch an ges of th e ten don , th ese tears h ave th e best h ealin g rates followin g surgical repair. Con sequen tly, th at is th e recom m en d treatm en t. Partial-thickness cuff tears can be treated with an exten ded n on operative course. Th e in tact portion of th e cuff continues to transm it force to the m uscle, so there is less ch an ce of atrophy or fatty in filtration . If symptom s persist, surgical m anagem ent is an option. Surgery consists of subacrom ial decompression with debridem en t of th e tear if it in volves less th an 50% of th e ten don , an d repair if m ore than 50% of the tendon is torn.

Surgical repair of rotator cuff tears can be don e eith er open or arth roscopically. Th e in itial h ealin g rates with arth roscopic repair were inferior to open repair but, with improved techniques and in creasing experience, m ore recen t series are reportin g com parable repair rates in all but th e largest tears.

Calcific Tendonitis Calcific tendonitis is a com m on disorder in m iddle-aged patien ts in wh om calcification occurs with in th e ten don s of th e rotator cuff, especially th e supraspin atus.

Pathophysiology and Classification Th e etiology of calcific ten don itis is un kn own but it in volves m ultifocal, cell-m ediated calcium deposition within the tendons of the rotator cuff. Calcific tendonitis differs from rotator cuff tendonitis in that it tends to occur in wellvascularized areas of the tendons 1 to 2 cm proxim al to th eir insertion, rather than at the dysvascular tissue at the tendon ’s in sertion in to th e tuberosity. Furth erm ore, th e n atural h istory of calcific ten don itis is th at of a self-lim ited disorder th at resolves with tim e rath er th an th e gradual worsen in g seen in rotator cuff ten don itis. Calcific ten don itis progresses th rough th ree distin ct ph ases: th e precalcifyin g stage, th e calcifyin g stage, an d the postcalcifying or resorptive ph ase. During the precalcifying stage, histologic m etaplasia of the tenocytes into ch ondrocytes occurs within the tendon. This ph ase is gen erally asymptom atic. Th e calcifyin g stage in volves th e deposition and coalition of calcium within the tendon into welldelin eated deposits. Th is stage is often asymptom atic, but wh en symptom s do occur th ey are gen erally sim ilar to th ose ch aracteristic of patients with m ild to m oderate subacrom ial impin gem en t. Radiographs at this stage dem onstrate a hom ogenous, well-dem arcated calcium deposit within the ten don . The duration of this stage is variable, and it m ay last several years. The resorptive phase in volves an inflam m atory response by the body to the deposit resulting in break up and resorption of the calcification. Patients in this stage can experience severe pain secondary to the in creased intratendinous pressure generated by the inflam m atory response associated with resorption. Radiographs will dem on strate a fluffy, poorly delin eated deposit. Presentation Calcific tendonitis is m ost com m on in patients between 40 an d 50 an d is m ore frequen t in wom an th an m en . Th e patien t’s symptom s depen d on th e stage of th e disease. During the early stages, patien ts m ay be asymptom atic or com plain of dull an terior lateral sh oulder pain th at is worse with activity, as is com m on in impin gem en t syn drom e. In the resorptive ph ase, patients m ay have severe, acute-onset sh oulder pain th at is extrem ely debilitating and can m im ic a septic join t.


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from subacrom ial injection of a m ixture of local anesthetic an d corticosteroid. Many auth ors h ave reported success with percutan eous n eedling of the deposits either alone or in com bin ation with a steroid in jection in th ese patien ts. For patien ts in th e calcifyin g stage, n on operative treatm en t with a rotator cuff–directed physical th erapy program is generally successful in alleviatin g the impingem ent-type pain . If th is fails, th e deposits can be surgically excised.

Acromioclavicular Joint Arthritis

Figure 13.57 The characteristic calcification with the supra-

spinatus tendon seen in calcific tendonitis. (From Iannotti JP, Williams GR. Disorders of the Shoulder: Diagnosis and Management, 2nd ed. Philadelphia: Lippincott Williams & Wilkins, 2007, with permission.)

Physical Examination In th e precalcifyin g an d calcifyin g stages, physical exam in ation fin dings are sim ilar to subacrom ial impingem ent, with a m ild decrease in ROM an d positive impingem en t signs. Durin g th e resorptive ph ase, th e patien t m ay h ave severely lim ited active and passive m otion accompanied by in tense pain . Radiographic Findings Radiograph s are diagn ostic for th is disorder an d will dem on strate calcification with in th e rotator cuff ten don (Fig. 13.57). A single AP view m ay m iss th e calcification if overlyin g bon e is presen t, so addition al AP radiograph s in intern al and external rotation can be h elpful. The scapular Y an d axillary views are useful for visualizing calcification with th e subscapularis or posterior cuff m uscles. Special Tests Radiograph s are diagn ostic of calcific ten don itis, so n o further tests are n ecessary. Differential Diagnosis Calcific tendonitis is differentiated from other disorders of the rotator cuff by the presence of calcification within the ten don on plain radiograph s. In patien ts presen tin g with acute pain characteristic of the resorptive phase, consideration m ust be given to septic arthritis. If the patient has any system ic sign s of infection or underlyin g m edical problem s m akin g h im m ore prone to in fection, the disorders can be distin guish ed by aspiration of th e join t. Treatment Th e vast m ajority of patien ts with calcific ten don itis respond well to nonoperative treatm en t. Patients presenting with severe pain in the resorptive phase will benefit

Arth ritis of th e AC join t is very com m on , an d because of th e join t’s proxim ity to th e subacrom ial space, often con tributes to symptom s in patien ts with rotator cuff path ology.

Pathophysiology Acrom ioclavicular join t arth ritis can occur as a con sequen ce of several disease processes. Th e th ree m ost com m on are prim ary osteoarthritis, posttraum atic arthritis, and osteolysis of the distal clavicle. As in oth er joints, prim ary osteoarthritis in volves progressive cartilage loss resultin g in join t space narrowing, sclerosis, and osteophyte form ation. O steoarth ritis of the AC join t is ubiquitous, with intrinsic degeneration of the in tra-articular disk in m ost in dividuals by age 40. Som e radiograph ic eviden ce of arth ritis is present in the m ajority of adults over the age of 50; h owever, the m ajority of th ese patien ts are asym ptom atic. Sym ptom atic posttraum atic arth ritis is com m on , occurrin g in approxim ately 10% to 15% of th ose in dividuals with grade I or grade II AC separation s. Ah istory of traum a from a previous fall or in jury durin g a con tact sport is com m on . Iden tifyin g th e subset of patien ts with a h istory of traum a is important because, in these individuals, an elem ent of AC instability m ay contribute to their pain . Patients with osteolysis of th e distal clavicle are generally younger and typically involved in repetitive weight-lifting activities. The etiology of this condition is thought to be due to stress fractures of th e subchondral bone and secondary join t breakdown . Th ey com plain of pain over th e AC join t, particularly with ben ch pressin g, dips, flies, an d push -ups. Presentation Patien ts typically presen t with pain over th e top of th e sh oulder, occasion ally with radiation up into the trapezius or down th e sh oulder. Th e pain is often a m ild ach e, worsen ed with specific activities, especially reach in g across th e body. Symptom s can be worse at n igh t, an d lyin g or rollin g on to th e in volved side m ay awaken th e patien t from sleep. Physical Examination In spection m ay reveal prom in en ce due to previous traum a with som e residual separation or hypertrophy of th e distal clavicle. Palpation yields ten dern ess directly over th e AC joint. The joint is compressed by having the patient place th e arm in adduction across th e body at th e level of th e sh oulder. In sym ptom atic patien ts, th is m an euver will

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AC separation , in flam m atory arthritis, and septic arth ritis. Many patien ts with rotator cuff pathology will present with sym ptom s sim ilar to those seen in AC joint arthritis, an d it is not un com m on for the two entities to coexist. Generally, pain with palpation directly over the AC joint is due to AC arthritis whereas pain associated with cuff path ology localizes over the anterolateral shoulder and deltoid.

Figure 13.58 Anterior-posterior radiograph of the right shoul-

der demonstrating joint space narrowing, sclerosis and osteophyte formation typical of acromioclavicular joint arthritis.

reproduce th eir pain . In stability is exam in ed by graspin g th e distal clavicle an d attemptin g to tran slate it in an an terior–posterior or superior–in ferior direction while the opposite h an d stabilizes th e acrom ion .

Radiographic Findings As described in the section on AC sprains, the AC joint is best visualized in th e AP plan e usin g th e Zan ca view. With AC arth ritis, th ere will be join t space n arrowin g, sclerosis, juxtacortical cysts, an d osteophyte form ation (Fig. 13.58). Th e axillary view provides furth er visualization of th e join t space as well as any an terior or posterior tran slation of th e distal clavicle. In osteolysis, th e distal clavicle is en larged an d appears radiolucen t. In th is con dition , th e join t space m ay actually appear in creased. Special Tests Additional studies are generally not necessary in the diagnosis of AC arthritis. Rarely, stress radiographs can be used to evaluate th e con tribution of in stability to th e patien t’s complaints. In complex cases, an injection of 1% lidocaine in to th e AC join t followed by repeat exam in ation can be used to con firm th e AC join t as th e source of th e patien t’s pain . Assum in g th e m edication is correctly placed in th e join t space, pain from AC arth ritis sh ould be tem porarily elim in ated by th e in jection . Differential Diagnosis Acrom ioclavicular joint pain m ay be due to a n um ber of entities oth er th an degen erative arth ritis. Th ese in clude acute AC join t separation , ch ron ic pain or in stability followin g

Treatment Th e treatm en t of prim ary osteoarth ritis, posttraum atic arthritis, and osteolysis is sim ilar. It is important to rem em ber th at AC arth ritis is a com m on radiograph ic fin din g, an d only th ose patients wh o are symptom atic warrant treatm en t. In itial treatm en t involves activity m odification an d NSAIDs. In m ildly sym ptom atic patien ts, th is is often effective in reducing their acute inflam m ation, and they can gradually return to th eir n orm al activities with out a return of pain . In th e weigh t-liftin g ath lete with osteolysis, ch an ging the grip distan ce or elim in ating bench presses and dips from the workout routine m ay elim in ate symptom s. If pain persists, an in jection of corticosteroid in to th e join t often provides dram atic if n ot perm an en t relief. Up to th ree in jection s can be perform ed for recurren t sym ptom s. Surgical treatm en t with join t debridem en t an d rem oval of th e distal en d of th e clavicle is curative in m ost patien ts. Th is can be don e with eith er an open or arth roscopic procedure. Care is taken to keep the resection lateral to the CC ligam ents in order to avoid destabilizing th e distal clavicle. In patien ts with symptom atic AC join ts wh o are un dergoing surgery for the treatm ent of rotator cuff pathology, con servative treatm en t is generally bypassed and excision of th e distal clavicle is perform ed at th e tim e of th e cuff procedure.

Glenohumeral Arthritis Although less com m on th an arthritis of the hip and knee, degen erative arth ritis of th e GH join t is still relatively com m on . As in any join t in the body, the characteristic fin ding of GH arthritis is destruction of the articular cartilage, an d a num ber of different pathologic en tities can lead to this destruction. Given the importan ce of the periarticular soft tissues in shoulder function, the effect of arthritis on these structures is particularly important in determ ining the symptom atic effects an d treatm ent of th e disease.

Pathophysiology and Classification Osteoarthritis is th e m ost com m on form of GH arthritis. Th e exact etiology of th is disease con tin ues to rem ain an area of active research. As in oth er join ts, the characteristic findings on radiographs include joint space narrowing, osteophyte form ation , subch on dral sclerosis, an d juxtaarticular cysts. The pathognom ic finding of osteoarthritis of the GH join t is the presence of osteophytes along the in ferior m argin of the hum eral articular surface (Fig. 13.59). Th ese osteophytes in crease ten sion with in th e an terior join t


A

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B Figure 13.59 Anterior-posterior (A) and axillary (B) radiographs demonstrating moderately se-

vere glenohumeral arthritis. Osteophytes along the inferior humeral neck are pathognomonic of osteoarthritis. (From Iannotti JP, Williams GR. Disorders of the Shoulder: Diagnosis and Management, 2nd ed. Philadelphia: Lippincott Williams & Wilkins, 2007, with permission.)

capsule, leading to hypertrophy of this structure and a characteristic decrease in external rotation. Disease progression leads to a preferential posterior wear of the glenoid eventually resulting in posterior subluxation of th e h um eral h ead. Th e disease process appears relatively protective of th e rotator cuff, wh ich is in tact in 90% of th ese patien ts. A secon d m ajor cause of GH arth ritis is in flam m atory arthritis, especially rheum atoid arthritis. In these patients, the initiatin g event in cartilage destruction is a proliferative, inflam m atory process of the synovium . Unfortunately, th e destructive process is n ot lim ited to th e articular cartilage but also in volves th e surroun din g soft tissue, leadin g to attenuation and rupture of capsular restraints and rotator cuff. On radiographs, the osteophytes and sclerosis of osteoarth ritis are absen t, replaced by diffuse osteopen ia an d periarticular erosion s in areas wh ere th e syn ovium h as access to the bone (Fig. 13.60). Glenoid wear tends to be sym m etrical, and patients do n ot have th e dram atic loss of extern al rotation seen in osteoarth ritis. End-stage rotator cuff disease can lead to a un ique form of arth ritis term ed cuff tear arthropathy. With m assive, ch ronic rotator cuff tears, the hum eral head can m igrate superiorly, leading it to articulate with th e superior m argin of th e glen oid an d th e un dersurface of th e acrom ion (Fig. 13.61). Th is leads to destruction of th e articular surface an d, if loss of the CAligam ent occurs, can result in anterior– superior subluxation of th e hum eral head with attem pted abduction of the arm . These patients often have significant pain an d complete fun ction al loss or pseudoparalysis of the shoulder. A n um ber of oth er disease processes, in cludin g osteon ecrosis, GH dislocation s, an d posttraum atic articular incongruity, can lead to destruction of th e GH articular surfaces. In m ost cases, th is results in secon dary osteoarth ritis with join t destruction an d symptom s sim ilar to prim ary

A

B Figure 13.60 Anterior-posterior (A) and axillary (B) radiographs

demonstrating rheumatoid orthritis of the glenohumeral joint. Note the periarticular osteopenia, symmetric cartilage loss, and lack of osteophytes. (From Iannotti JP, Williams GR. Disorders of the Shoulder: Diagnosis and Management, 2nd ed. Philadelphia: Lippincott Williams & Wilkins, 2007, with permission.)

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Figure 13.62 Radiograph demonstrating neuropathic arthropa-

Figure 13.61 Anterior-posterior radiograph demonstrating the

superior humeral translation seen in cuff tear arthropathy. (From Iannotti JP, Williams GR. Disorders of the Shoulder: Diagnosis and Management, 2nd ed. Philadelphia: Lippincott Williams & Wilkins, 2007, with permission.)

osteoarth ritis, alth ough th e specific patien t presen tation an d clin ical course m ay be altered by th e in itiatin g process. Decreased proprioception can lead to a h igh ly destructive n europath ic arth ritis of th e sh oulder. Th ese patien ts will have dram atic bone loss on radiographs and fun ction al deficits, but often presen t with m uch less pain th an on e would expect given th eir radiograph ic fin din gs (Fig. 13.62). Th e m ost com m on cause of n europath ic arth ropathy in the shoulder is syringomyelia of the cervical spin e. Recogn ition of a n europath ic sh oulder sh ould prom pt detailed n eurologic evaluation an d MRI of th e cervical spin e.

Presentation Patien ts with GH osteoarthritis generally present with a ch ief com plain t of pain . Typically, th e pain h as an in sidious on set, is progressive, an d in ten sifies with use. Patien ts m ay also n otice som e lim itation of m otion , especially extern al rotation . Th e pain often in terferes with sleep, especially if the patient rolls or lies on the involved side. The presentation of other form s of GH arthritis depen ds on th e un derlyin g disease. Patien ts with rh eum atoid arth ritis m ay already kn ow th eir diagn osis or presen t with pain an d effusion s in m ultiple join ts. In cuff tear arth ropathy, the pain is typically accompan ied by the in ability to raise the affected arm and weakness typical of m assive rotator cuff tears.

thy with complete destruction of the normal joint architecture. (From Iannotti JP, Williams GR. Disorders of the Shoulder: Diagnosis and Management, 2nd ed. Philadelphia: Lippincott Williams & Wilkins, 2007, with permission.)

Physical Examination In prim ary osteoarth ritis, atrophy about th e sh oulder girdle m ay be presen t secon dary to disuse. Palpation of th e join t often dem on strates crepitan s with m otion as th e in con gruous surfaces slide past each other. Posterior joint line tenderness m ay be present. Active m otion is typically lim ited by pain , whereas passive m otion is decreased secon dary to capsular con tracture. Th e m ost dram atic fin din g is often a significant loss of external rotation . With the arm at the side, these patients often have zero degrees of, or even n egative, extern al rotation . Th ey typically h ave sign ifican t pain with stretch of the an terior capsule, which can be dem on strated be placin g th e arm in m axim al extern al rotation an d th en gen tly applyin g a m ild extern al rotation al force. Alth ough the lim ited ROM can m ake the evaluation of th e rotator cuff difficult, it is im portan t to evaluate, as cuff integrity can have a significan t impact on treatm ent if the decision is m ade to proceed with arth roplasty. Patien ts with inflam m atory arthritis are likely to h ave a relatively preserved ROM but m ay lack stren gth secon dary to rotator cuff tears. In patien ts with cuff tear arth ropathy, sign ificant h ollowin g about the scapula is often present, secon dary to atrophy of the cuff m uscles. If the patien t has an terior–superior subluxation, the hum eral head will be visible anterior to the acrom ion. Radiographic Findings True AP and axillary radiographs will dem onstrate joint space narrowin g in all patients with arthritis. Once th e


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presen ce of cartilage loss is observed, it is im portan t to distin guish between th e various types of arth ritis, as th is will h ave an impact on progn osis an d treatm en t. Th e prim ary distinction is between osteoarthritis and inflam m atory arthritis. This is easily accomplish ed given the ch aracteristic osteophyte form ation and sclerosis seen with osteoarth ritis of th e GH join t. In patien ts with osteoarth ritis, the axillary radiograph is useful for evaluatin g th e am ount of posterior glenoid bon e loss and any posterior subluxation of th e h um eral head.

Special Tests In th e straigh tforward presen tation of osteoarth ritis, n o special studies are n eeded. In patien ts bein g considered for sh oulder arthroplasty, CT scans are useful to furth er defin e posterior glen oid wear. Wh en th ere are question s regarding the integrity of th e rotator cuff, especially in patients with in flam m atory arth ritis, MRI con tin ues to be th e study of ch oice. Early in th e course of som e secon dary causes of osteoarth ritis, such as osteon ecrosis, MRI is also useful in dem onstrating ch anges that m ay not be apparent on plain radiograph s. Patien ts with radiograph ic fin din gs of inflam m atory arthritis with out a diagnosis of a system ic in flam m atory process (rheum atoid arthritis, lupus, spondyloarthropathy) should be referred to a rheum atologist for further clinical and laboratory evaluation. Differential Diagnosis Th e differen tial diagn osis of GH arth ritis con sists of any con dition that can presen t with a stiff, painful sh oulder. Th e m ost com m on en tities to presen t in a sim ilar m an n er are adhesive capsulitis and rotator cuff disease. Th e distinction can generally be easily accomplished through history, physical exam in ation , an d radiograph ic studies. It is im portan t to rem em ber th at m ore th an on e of th ese en tities can exist in a given shoulder. Generally, if significant loss of th e join t space h as occurred, arth ritis is respon sible for the patient’s symptom s. Treatment Th e treatm en t of arth ritis depen ds on th e patien t’s discom fort and ability to function. For patients with m inor or m oderate pain an d preserved fun ction , n on operative treatm en t con sisting of activity m odification and anti-inflam m atory m edications is utilized. Physical therapy m ay be useful in m ain tain ing the ROM, but it can also aggravate the patient’s symptom s. For patien ts with m ore significant pain an d a decreasin g ability to perform th e activities th ey wan t or need to do, shoulder replacem ent is an excellent treatm en t option . Total sh oulder arth roplasty (TSA) in volves replacem en t of th e h um eral h ead with a m etal sph ere an d replacem en t of th e glen oid surface with an ultra-h igh -m olecular-weigh t polyethylen e disc (Fig. 13.63). In m ost curren t design s, th e hum eral compon ent is placed in press-fit m ann er while the glenoid component is held in place by bone cem ent.

Figure 13.63 Anterior-posterior view demonstrating a total

shoulder arthroplasty used to treat glenohumeral arthritis. (From Iannotti JP, Williams GR. Disorders of the Shoulder: Diagnosis and Management, 2nd ed. Philadelphia: Lippincott Williams & Wilkins, 2007, with permission.)

Patien ts often ach ieve dram atic, lastin g pain relief an d 85% to 90% good to excellent results h ave been reported at 10 to 15 year follow-up. Return to m ost activities, in cludin g golf, is perm itted, although the patien t is generally advised not to repetitively lift m ore than 25 pounds with the involved extrem ity. Con troversy exists over th e n eed to resurface th e glenoid, but recent evidence suggests that, in patients with an intact rotator cuff, TSA provides superior fun ction and pain relief wh en com pared to h em iarth roplasty. Total sh oulder arth roplasty is a resurfacin g procedure and relies on the integrity of surrounding soft tissue structures to provide stability and proper fun ction of the join t. Improper position in g or sizin g of th e compon en ts or loss of in tegrity or fun ction of th e rotator cuff can lead to sign ifican t decreases in th e postoperative fun ction an d early failure of th e prosth esis. Given th e propen sity for posterior glen oid wear with GH osteoarth ritis, it is importan t to carefully evaluate th e exten t of glen oid bon e loss on th e preoperative axillary radiograph s an d CT scan . Occasion ally, th e am oun t of posterior bon e loss will preclude th e placem en t of a glen oid com pon en t, in wh ich case th e glen oid can be ream ed to create a sm ooth surface with placem en t of a h em iarth roplasty

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m otion of the GH joint. Given th e param ount role of GH m otion in proper shoulder girdle function, patients often find this disease rem arkably debilitatin g. Prim ary adhesive capsulitis is an idiopathic process that tends to occur in m iddle-aged patients. Restricted ROM can also occur as a result of a traum atic in jury, surgery, or oth er path ologic process of th e sh oulder, in wh ich case it is referred to as secondary adhesive capsulitis.

Figure 13.64 The reverse shoulder prosthesis is used to treat

some patients with cuff tear arthropathy. The articular geometry is reverse, so that the convex component is placed on the glenoid and the concave component is on the humerus. (From Iannotti JP, Williams GR. Disorders of the Shoulder: Diagnosis and Management, 2nd ed. Philadelphia: Lippincott Williams & Wilkins, 2007, with permission.)

on th e h um eral side. Hem iarth roplasty is also favored in patien ts with osteoarth ritis an d an irreparable rotator cuff tear, as well as th ose un der th e age of 50. Glenoid bone loss is an im portan t con sideration wh en advisin g th e patien t about con tin ued con servative treatm en t for osteoarth ritis. Th e patien t n eeds to un derstan d that once he begins to have significant posterior wear and subluxation, contin uation of nonoperative treatm en t m ay lead to in sufficien t glen oid bon e for placem en t of a glen oid componen t during future arthroplasty. The functional results of TSA in patien ts with in flam m atory arth ritis are in ferior to th ose of patien ts with osteoarth ritis secon dary to th e attrition of th eir surroun din g soft tissue en velope. In cuff tear arthropathy, glenoid replacem en t is con train dicated because th e h um eral h ead is n o lon ger con cen trically articulatin g with th e glen oid. Th ese patien ts can be m an aged with h em iarth roplasty or a n ew type of prosth esis kn own as a reverse shoulder arthroplasty. In this device, the geom etry of the shoulder is reversed an d th e sph ere is placed on th e glen oid side of the articulation while the concave surface is placed on the hum eral side (Fig. 13.64).

Adhesive Capsulitis Adhesive capsulitis, or frozen shoulder, is a painful con dition ch aracterized by th e loss of both active an d passive

Pathophysiology and Classification Despite m ore th an 100 years of fam iliarity with th e con dition , th e un derlyin g etiology of frozen sh oulder rem ain s un clear. Diabetes m ellitus an d thyroid disease are predisposin g factors for th e developm en t of idiopath ic adh esive capsulitis. The decrease in GH m otion is associated with hypertrophy of th e capsular an d ligam en tous restrain ts to sh oulder m otion as well as inflam m ation of th e joint’s synovial lin in g. In m ost patien ts, th e process is self-lim ited, with th e even tual return of n ear n orm al m otion . Idiopath ic adh esive capsulitis h as been divided in to three distinct but overlappin g clinical phases: freezing, frozen, and thawing. During the freezing ph ase there is an in sidious, progressive loss of shoulder m otion, often associated with sign ifican t pain with both rest and activity. In th e frozen ph ase, th e loss of m otion stabilizes. Pain is gen erally lim ited to activities th at place th e join t n ear its en d ROM. Th e th awin g ph ase is ch aracterized by a gradual return of th e GH m otion . Th e duration of each ph ase is highly variable, with the overall course of the disease gen erally ran gin g for 9 m on th s to 3 years. Presentation Th e presen tation of adh esive capsulitis depen ds on th e stage of the disease. The m ajority of patients will present in th e freezin g phase complaining of pain over th e anterior lateral aspect of th e sh oulder an d arm . Th is pain is gen erally described as a dull ach e an d is often worse at n igh t, leadin g to nocturn al awaken in g. Th e discom fort is often accom pan ied by a sh arp pain with m ovem en ts th at stretch th e in flam ed capsular structures such as fastening a bra, puttin g on a coat, or reach in g in to th e back seat of a car. As the disease progresses, patien ts will note decrease in the functional ROM of their shoulder. Th ey m ay also h ave pain an d m uscle cram pin g about th e scapula as they attempt to compensate for decreased GH m otion with increased scapulothoracic m otion. Physical Examination Th e h allm ark of frozen sh oulder on physical exam in ation is the loss of both active and passive ROM. Restriction is presen t in several plan es but is often m ost pron oun ced in extern al rotation an d abduction . It is n ot un com m on for patien ts to lack sufficien t abduction to exam in e rotation at 90 degrees of abduction. When exam ining patients with adh esive capsulitis, it is particularly importan t to identify an d control compensatory m otions in order to get a true m easurem en t of GH m otion. Patients will often h ave sh arp


pain wh en a stretch is applied to th e capsule at th e extrem e ran ges of passive m otion .

Radiographic Findings Radiograph s of patien ts with adh esive capsulitis are gen erally un rem arkable. Th ey are importan t to rule out oth er con ditions th at can lead to restricted ROM, especially GH arthritis. Special Tests Frozen sh oulder is diagn osed on th e basis of h istory an d physical exam in ation fin din gs, an d n o special tests are needed. In rare circum stan ces, arth rography can be used to con firm the diagnosis. The n orm al sh oulder will accom m odate 15 to 30 m L of contrast fluid, whereas the contracted capsule of the typical frozen shoulder will hold less than 10 m L. Postcontrast radiographs will also dem onstrate a sm all, blun ted axillary fold. O ccasion ally, MRI exam ination is warranted to rule out other soft tissue disorders about the shoulder that can lead to pain and secondary adh esive capsulitis. Differential Diagnosis Durin g th e early ph ases of adh esive capsulitis, it can be extrem ely difficult to differen tiate th e con dition from rotator cuff disease. Both groups of patien ts will presen t with pain th at is very sim ilar in n ature. It is n ot un com m on for patien ts with adh esive capsulitis to presen t having selfdiagn osed th em selves with im pin gem en t syn drom e. Patients with cuff path ology will often have sm all decreases in th e range of active m otion, especially internal rotation. Furth er com plicatin g th e issue, patien ts with frozen sh oulder will often experien ce som e degree of secon dary im pin gem en t syn drom e as th eir tigh t posterior in ferior capsule leads to an terior superior translation of the hum eral head toward the acrom ion with elevation of the arm . Th e distin ction is best accomplish ed over tim e. Both sets of patients can be started on an initial therapy program th at emph asizes capsular stretch in g an d stren gth en in g of th e rotator cuff m uscles outside of th e impin gem en t zon e. In the compliant patient, reexam ination in 1 m onth will gen erally reveal an im provem en t in th e RO M in patien ts with cuff disease. In patients in the early stages of adhesive capsulitis, further decrease in th e ROM will often occur despite the stretching program . Glen oh um eral arth ritis an d m issed traum atic in juries to the shoulder, especially posterior GH dislocations, can lead to decreased ROM. Th ese disorders can be easily differen tiated on plain radiographs. Treatment Th e m ost importan t aspect of treatm en t of th e patien t with adh esive capsulitis is educatin g the patien t regarding the self-lim ited nature of th e disease. The variable tim e course an d generally slow restoration of m otion can m ake the treatm ent of this condition extrem ely frustrating for both

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patien t an d physician . Durin g th e freezin g ph ase, th e patien t is started on a passive stretch in g program in an attempt to m ain tain as m uch m otion as possible. Alth ough supervision of th e program by a therapist is often helpful, in order to be effective, th e stretch in g m ust be perform ed by the patient at hom e, a m inim um of four to five tim es a day. For patien ts with sign ifican t pain , NSAIDs or an in tra-articular cortison e in jection are h elpful in relievin g the patients’ symptom s, so that they can participate in the therapy program . The stretching is contin ued during the frozen and thawin g ph ases in an attempt to restore m otion as quickly as possible. Th e m ajority of patien ts are left with som e sm all lim itation s in GH m otion following adhesive capsulitis; h owever, these deficits rarely result in any fun ction al lim itation s. For patients with no improvem ent or a decrease in their ROM despite 3 to 6 m on th s of aggressive th erapy, operative in terven tion is a con sideration . Tradition ally, m an ipulation un der an esthesia h as been th e procedure of ch oice, alth ough fractures of th e proxim al h um erus are a significant risk. More recently, an arthroscopic capsular release h as been favored. Alth ough m ore in vasive, th is procedure allows con trolled section in g of th e con tracted capsular structures. Regardless of wh ich surgical option is utilized, aggressive postoperative th erapy is crucial to m ain tain in g th e in creased ROM ach ieved in th e operatin g room .

CONCLUSION Wh en h ealthy, th e sh oulder complex is able to ach ieve a rem arkable ROM wh ile gen eratin g sign ifican t power for th e fun ction al activities of th e upper extrem ity. In order to achieve these fun ctions, it relies on a complex interaction between m ultiple bones, joints, and m uscles, m aking it susceptible to a wide range of pathologic processes. Sign ifican t advances in our un derstan din g of th e fun ction of th e various elem en ts of th e complex, as well as advan ces in open an d arth roscopic surgical tech n iques, h ave led to an en h an ced ability to diagn ose an d treat dysfun ction about th e sh oulder. Disorders of th e sh oulder com plex rem ain an area of active orth opaedic research, an d future findin gs will con tin ue to advan ce our un derstan din g of th ese con dition s and our ability to diagnose and treat them .

RECOMMENDED READINGS Ten n en t DT, Beach WR, Meyers JF. A review of special test associated with shoulder exam in ation. Part I: The rotator cuff tests. Am J Sports Med 2003;31(1):154 –160. A detailed description of each of th e various special tests used in the evaluation of rotator cuff disease. Ten n en t DT, Beach WR, Meyers JF. A review of special tests associated with shoulder exam in ation. Part II: Laxity, instability, and superior labral an terior an d posterior (SLAP) lesion s. Am J Sports Med 2003;31(2):301 –307. A detailed description of th e m any of th e special tests used in th e evaluation of several com m on disorders of th e glen oh um eral join t.

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Ian notti JP, Ram sey ML, William s GR, et al. Nonprosthetic m anagem ent of proxim al hum eral fractures. Am J Bone Joint Surg 2003;85A(8):1578 –1593. This reprint of an Instruction Course Lecture describes th e m ultiple options available for the surgical treatm ent of proxim al hum erus factures. Robin son CM, Dobson RJ. An terior in stability of th e sh oulder after traum a. Br J Bone Joint Surg 2004;86-B(4):469 –479. An excellent review of the epidem iology, pathoanatomy, and results of open an d arth roscopic treatm en t of traum atic an terior shoulder instability.

William s GR, Rockwood Jr. CA, Biglian i LU, et al. Rotator cuff tears: Why do we repair th em ? Am J Bone Joint Surg 2004;86-A(12):2764 – 2776. Th is article provides a th orough review of both n on operative an d operative m anagem ent of rotator cuff tears. Boileau P, Sin n erton RJ, Ch uin ard C, et al. Arth roplasty of th e sh oulder. Br J Bone Joint Surg 2006;88-B(5):562 –575. A comprehen sive discussion regarding th e design rationale beh in d the current generation of im plants available for sh oulder replacem ent, as well as a review of factors influencing th e success of shoulder arthroplasty.

14

The Elbow Brian Magovern

Matthew L. Ram sey

INTRODUCTION Wh ile th e sh oulder allows placem en t of th e upper extrem ity throughout a large sphere of m otion, the elbow allows fin e-tun ed m otion s with in th at sph ere. Th rough its th ree articulations and a complex interplay of m uscles and ligam ents, the elbow is capable of both fine m otion s an d great power. Th e elbow h as a very un ique an atom ical an d biom ech an ical profile, wh ich adds to th e com plexity wh en evaluatin g an d treatin g disorders of th is region . Traum atic an d atraum atic elbow conditions can have a dram atic influence on a patient’s ability to fun ction during work, recreation , or activities of daily livin g. Th is ch apter describes th e anatomy, biom echanics, evaluation , an d m anagem ent of th e m ost com m on pathologic con ditions of th e elbow.

FUNCTIONAL ANATOMY Th e elbow is a h igh ly con strain ed h in ge join t (troch ogin glym oid) that is m ade up of th ree articulations. Th e th ree join t surfaces con sist of hyalin e cartilage an d are foun d with in on e sh ared join t capsule. Th e uln oh um eral join t is the prim ary articulation of the elbow. It allows flexion an d extension and provides a large degree of elbow stability. The other two articulations are the radiocapitellar an d proxim al radiouln ar join ts, wh ich allow for supin ation an d pron ation . Path ologic con dition s th at in terfere with th ese important joint surfaces, such as rheum atoid arthritis (RA), will lead to pain ful loss of m otion an d poor fun ction . Several im portan t structures are vital to th e n orm al fun ction of these articulations. They con sist of bon es, ligam en ts, and m uscles, which provide static and dyn am ic stability as well as m otion an d power. Con dition s th at disrupt these structures lead to a breakdown in the complex chain necessary for fluid and powerful elbow m otion .

Osteology Th e distal h um erus is a trian gular-sh aped lon g bon e th at flatten s in th e coronal plan e as it n ears th e elbow join t (Fig. 14.1). Distally, it flares m edially and laterally into two strong bony colum n s, leaving a very thin segm en t of in terven in g bon e. Th e two colum n s en d as th e m edial an d lateral epicondyles, respectively, which serve as important attachm ent sites for the ligam ents and m uscles th at cross th e elbow. At th e level of th e join t, th e h um eral colum n s are separated by two m ain articular segm ents. Medially, th e spool-shaped troch lea m akes up the m ajority of the ulnoh um eral articulation . Lateral to th e troch lea lies th e capitellum , a convex projection of the distal hum eral joint surface, wh ich articulates with th e con cave radial h ead to form th e radiocapitellar join t. In th e coron al plan e, th e troch lea h as a 6 to 8 degree valgus alignm ent, which gives th e elbow its carryin g an gle. Com m on ly, wom en h ave a larger carryin g angle than do m en. In th e sagittal plan e, the capitellum is angled 30 degrees relative to th e h um eral shaft, which m ay be h elpful in th e evaluation of fractures. Th e proxim al uln a is a saddle-sh aped articulation th at closely m atch es th e sh ape of th e troch lea on th e h um eral side of the join t. Th e elbow, unlike the sh oulder, has an inheren t bony stability prim arily because of th e congruity of th ese two irregular surfaces. Th e uln a is also m ade up of th e an terior coron oid process an d th e posterior olecran on process, wh ich act as im portan t ten don , ligam en t, an d capsular attachm en t sites. Th e coronoid is an important buttress to prevent anterior dislocation of the elbow joint. The distal h um erus h as two correspon din g con cavities kn own as the coronoid and olecranon fossae. The coronoid process en gages its fossa at greater th an 120 degrees of flexion and the olecran on process at less than 20 degrees of flexion (Fig. 14.2). Bony stability is the m ost prevalen t during these en d ran ges of m otion . Th e proxim al uln a also articulates with th e proxim al radius at th e area kn own as th e lesser sigm oid n otch .

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Lateral supraepicondylar ridge

Medial supraepicondylar ridge

Lateral supraepicondylar ridge

Radial fossa

Olecranon fossa

Coronoid fossa Medial epicondyle (common flexor orgin)

Lateral epicondyle (common extensor orgin)

Trochlea

Capitulum

Medial Flexors epicondyle for Ulnar nerve

Extensors Anconeus

Trochlea Trochlear notch

Olecranon

Radial notch Head Neck

Tuberosity for

Subtendinous bursa Biceps brachii

Tubercle on coronoid process

Lateral epicondyle for

Cutaneous triangular for olecranon bursa Head Neck

Tuberosity of ulna Supinator crest

Tuberosity

Supinator fossa Posterior border

Posterior oblique line

Anterior oblique line

A.

Anterior View

B.

Posterior View

Figure 14.1 Osteology. (Reproduced with permission from Agur AMR, Dalley AF. Grant’s Atlas of Anatomy. 11th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2004.)

The proxim al en d of the radius consists of the radial neck and head. The radial h ead is slightly elliptical an d concave. It is an importan t secondary stabilizer to valgus stress of the elbow an d a restraint to proxim al m igration

of th e radius. It articulates with both th e capitellum an d the proxim al uln a to allow n early 200 degrees of rotation. By n ecessity, m ost of th e radial h ead is covered in articular cartilage. This is clinically important in th e treatm ent of radial h ead fractures, as th ere is rough ly a 90-degree “safe’’ arc for placem ent of in ternal fixation . The radial h ead is supported by the radial n eck distally. Further distal, the radial tuberosity serves as th e attach m en t site for th e distal biceps ten don .

Ligaments

Figure 14.2 The coronoid and olecranon process engage at terminal flexion and extension so bony stability of the ulnohumeral joint is greatest at these end ranges of motion. (Reproduced with permission from Bucholz RW, Heckman JD, Court-Brown C, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)

Two m ajor ligam en t com plexes offer stability to th e elbow join t. Th ey are m ost im portan t in th e arc of 20 to 120 degrees, wh ere th ere is less bony stability. O n th e m edial side, the m edial ulnar collateral ligam ent (MUCL) complex is a triangular structure that acts as a m ajor restraint to valgus stress (Fig. 14.3). It is m ade up of three components. The an terior bundle is the prim ary stabilizer to valgus stress an d spans from the undersurface of the m edial epicon dyle to th e sublim e tubercle on th e coron oid process of th e uln a. Th e posterior bun dle is foun d between th e m edial epicon dyle an d th e olecran on an d provides m ore stability in h igher degrees of flexion. The transverse bundle is a sm aller, less im portant structure that completes the triangle of th e MUCL com plex.

Chapter 14: The Elbow

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Humerus Biceps brachii tendon

Anular ligament of radius

Oblique cord Interosseous membrane

Medial epicondyle

Radius

Anterior band Posterior band

Of ulnar collateral ligament

Oblique band Olecranon Ulna

Tubercle for ulnar collateral ligament

Figure 14.3 Medial ulnar collateral ligament complex. (Reproduced with permission from Agur AMR, Dalley AF. Grant’s Atlas of Anatomy. 11th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2004.)

On the lateral side, th e lateral uln ar collateral ligam en t (LUCL) is a thickening of the elbow capsule that spans from the lateral epicondyle to a process on the proxim al ulna kn own as th e crista supinatoris (Fig. 14.4). The LUCL is th e prim ary restrain t to posterolateral rotatory in stability (PLRI) of the elbow. The annular ligam ent arises from the LUCL an d en compasses the radial head, adding stability to th e proxim al radius. Importan t capsular in sertion s m ake up th e rem ain der of th e static stabilizers to th e elbow. Th e an terior capsule inserts on th e slope of the coronoid process (not at the tip), offerin g restrain t to an terior subluxation of th e elbow. Th e posterior capsule lies deep to th e triceps. It does n ot offer significan t stability, but when diseased, it can play a m ajor role in elbow stiffn ess an d con tracture.

Muscles Th e elbow join t is powered by several m ajor m uscles. Th ese m uscles can be divided into groups based on the elbow m otion th at they perform . There are also m any important m uscles that cross the elbow joint providing m otor function to th e wrist and hand. Elbow extension is prim arily perform ed by th e triceps m uscle (Fig. 14.5). It is m ade up of three heads proxim ally that form one ten don that attaches to the olecranon process distally. It is innervated by th e radial nerve. Flexion of the elbow is driven by the structures of the anterior arm compartm ent (Fig. 14.6). The brachialis originates from the anterior hum erus and inserts just distal to the tip of the coronoid process along the anterior slope. It is the prim ary flexor of the elbow and has a dual inn ervation. Th e lateral fibers are innervated by the radial nerve, whereas

its m edial fibers are in n ervated by th e m usculocutan eous n erve. Th is allows lon gitudin al splittin g of th e brach ialis durin g th e an terior approach to th e h um erus. Th e brach ioradialis, also in n ervated by th e radial n erve, is a weak flexor of the elbow. It originates on th e lateral aspect of the distal h um erus an d in serts on th e radial styloid of th e wrist. Th e biceps m uscle adds addition al flexion stren gth but is m ore importan t as th e prim ary supin ator of th e forearm . It origin ates from two h eads proxim ally an d in serts on th e bicipital tuberosity of th e proxim al radius. It is in n ervated by the m usculocutaneous nerve. A fascial reflection known as th e bicipital aponeurosis or lacertus fibrosis exten ds m edially from th e biceps ten don on to th e forearm fascia coverin g th e m edian n erve an d brach ial artery. In som e cases of distal biceps ten don rupture, th e bicipital apon eurosis rem ain s in tact, preventing proxim al retraction of the m uscle belly. Th e supin ator provides secon dary supin ation stren gth . Fin ally, pron ation is m ain ly powered by th e pron ator teres (PT) with som e con tribution from th e rem ain in g flexor–pron ator m ass of m uscles th at origin ate from the m edial epicondyle. The pronator teres (PT) inserts on th e radial sh aft an d is inn ervated by the m edian n erve. Th ere are m any oth er importan t m uscle groups that origin ate or in sert at th e elbow but do n ot con tribute sign ificantly to elbow m otion . Th e lateral epicon dyle serves as the origination of the wrist and digital extensors, nam ely the exten sor carpi radialis longus and extensor carpi radialis brevis (ECRB), exten sor digitorum com m un is, an d exten sor carpi uln aris (ECU). The anconeus is a sm all m uscle posterior to th e ECU, wh ich m ay fun ction as a weak stabilizer to th e elbow, but its fun ction is n ot en tirely clear. Th e m edial epicon dyle serves as th e attach m en t site for th e PT,

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Figure 14.4 Lateral ulnar collateral ligament complex. (Reprinted with permission from O’Driscoll

SW, Horii E, Morrey BF, et al. Anatomy of the ulnar part of the lateral collateral ligament of the elbow. Clin Anat. 1992;5:296–303.)

flexor carpi ulnaris, flexor digitorum superficialis (FDS), an d flexor carpi radialis (FCR).

Neurovascular Structures Th e elbow is surroun ded by m ajor n eurovascular structures all with in close proxim ity to on e an oth er. Kn owledge of the relationship between structures in the elbow is crucial durin g surgical dissection as th ere is little room for error. The brachial artery runs along the m edial arm an d crosses anterior to the elbow joint as it bifurcates in to the radial and ulnar arteries underneath the bicipital apon eurosis (Fig. 14.7). Th e radial artery run s alon g th e m edial aspect of th e biceps ten don an d in to th e radial forearm . Th e uln ar artery con tin ues alon g th e uln ar side of th e forearm . The m edian nerve courses along with the brachial artery, passin g un der th e bicipital apon eurosis m edial to the artery. It then con tinues between th e FDS and FDP in to th e forearm . It supplies th e PT an d th e rem ain der of th e flexor–pron ator m ass. Th e uln ar n erve also travels alon g th e m edial arm , passin g in to th e posterior compartm en t th rough the interm uscular septum proxim al

to the elbow joint. It th en runs under the m edial epicon dyle in to th e cubital tun n el. Th e posterior bun dle of th e uln ar collateral ligam en t m akes up th e floor of th e cubital tun n el wh ile th e an terior bun dle lies an terior to th e n erve run n in g parallel to it. Th e n erve passes between the two heads of th e PT and runs alon g th e uln ar aspect of the forearm in to th e h an d. Th e m usculocutaneous nerve enters the anterior arm from undern eath th e coracoid process wh ere it supplies the coracobrach ialis, th e biceps, an d th e m edial two-th irds of th e brach ialis. It th en exits th e arm between th e biceps and brachialis m uscles proxim al to the elbow joint, form ing the lateral antebrachial cutan eous nerve. It pierces th e an terior fascia of th e forearm , becom in g subcutan eous an d is in dan ger durin g surgical approach es to th e anterior forearm , such as those used for distal biceps tendon repair. Th e radial n erve en ters th e arm from th e posterior cord of th e brach ial plexus an d passes posterior to th e h um erus in th e spiral groove. Th e n erve th en en ters th e anterior compartm ent of the arm between the brach ialis and the brachioradialis m uscles. It travels in close proxim ity to the an terior elbow capsule and bifurcates distal to th e elbow joint. Th e superficial branch runs on the


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2 Triceps tendon (2)

5

Brachioradialis (3)

3

1

4

Extensor carpi radialis longus (4)

Medial epicondyle Ulnar nerve

6

Lateral epicondyle (5)

Posterior ulnar recurrent artery

Common extensor tendon

Olecranon (1)

Anconeus (6 )

Fascia covering anconeus

Flexor carpi ulnaris

Anconeus

A. Posterior View

B. Posterior View

Figure 14.5 Posterior elbow muscles. (Reproduced with permission from Agur AMR, Dalley AF. Grant’s Atlas of Anatomy. 11th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2004.)

un dersurface of th e brach ioradialis an d provides sen sation to the radial forearm and first dorsal webspace of the hand. The deep bran ch becom es th e posterior in terosseous nerve (PIN) as it passes un der th e arcade of Struth ers an d into the supinator m uscle. The PIN th en travels alon g the radius and along th e interosseous m em brane, giving important branches to th e wrist an d digital extensors. It sh ould be noted th at th e PIN runs on th e opposite side of the bicipital tuberosity, wh ich sh ould be rem em bered during surgical approaches to the proxim al radius. Pronation ten ds to brin g th e n erve m edially, wh ile supin ation ten ds to put th e n erve in a m ore lateral position . Th erefore, durin g

the lateral approach to th e elbow, th e forearm should be pron ated to m ove th e PIN away from th e field of dissection (Fig. 14.8).

EVALUATION OF ELBOW DISORDERS History In th e evaluation of elbow disorders, th e h istory rem ain s th e m ost crucial compon en t of th e diagn osis. An in itial determ in ation of th e age of th e patien t, location of th e

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Biceps brachii

Musculocutaneous nerve

Medial intermuscular septum

Brachialis Inferior ulnar collateral artery Radial nerve Ulnar nerve Brachial artery Brachioradialis Median nerve Biceps brachii tendon Extensor carpi radialis longus Deep branch of radial nerve Radial recurrent artery Extensor carpi radialis brevis Superficial branch of radial nerve

Superficial head of pronator teres Ulnar artery Deep head of pronator teres Supinator Flexor carpi radialis

Radial artery

Anterior View

Figure 14.6 Anterior elbow muscles. (Reproduced with permission from Agur AMR, Dalley AF. Grant’s Atlas of Anatomy. 11th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2004.)

symptom s, and m echanism of injury will significantly narrow the differential diagn osis. An overh ead th rowin g ath lete with m edial elbow pain , for example, h as a very different set of possible diagn oses compared with an elderly wom an with ch ron ic elbow pain . Furth er in vestigation can

th en be tailored for each patien t. If th e m ech an ism of in jury is traum atic, m ake n ote of th e type of traum a an d th e position of th e arm at th e tim e of in jury. Ask th e patien t wh eth er th ere was a sen se of subluxation or wh eth er any reduction m an euver was required. If th e patien t presen ts


Figure 14.7 Elbow arteries and

nerves. (Reproduced with permission from Moore KL, Agur AM. Essential Clinical Anatomy. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

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Extensor carpi ulnaris

Supinator Supinator

Anconeus Posterior interosseous n.

Arcade of Frohse Radial n.

Pronation

Figure 14.8 Posterior interosseous nerve

during lateral approach. (Adapted from Hoppenfeld S, deBoer P. Surgical Exposures in Orthopaedics: The Anatomic Approach. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 1984.)

with an overuse in jury, determ in e th e length of tim e since the onset of symptom s, aggravating or alleviating factors, an d th e effect of any prior treatm en ts, particularly surgical in terven tion s. Th e location of th e symptom s will often be localized to th e m edial, lateral, or posterior aspects of th e elbow, h elpin g to greatly lim it th e differen tial diagn osis. If pain is th e m ain com plain t, n ote th e ch aracter of th e pain . Con stan t burn in g an d radiatin g pain is classically m ore neurogen ic, whereas activity-related pain is m ore typical of m usculoskeletal path ology. It is im portan t to rem em ber that symptom s m ay overlap in patients with cervical spine path ology. Question in g th e patien t for any n eck in jury or cervical spine complaints is, therefore, m andatory. While pain is th e m ost com m on presen tin g complain t, it is im portan t to n ote oth er sym ptom s as well. Patien ts with un stable elbows m ay report feelin g a “clun k’’ with certain activities an d arm position s. Patien ts with loose bodies will often complain of locking an d catching.

Physical Examination Th e physical exam in ation of th e elbow will often con firm the diagn osis after the h istory has narrowed down th e

differen tial. A system atic approach will en sure th at a com plete exam in ation is perform ed an d n o path ology is overlooked. Th e basic components of th e physical exam ination include inspection, palpation, range-of-m otion, stability, and a neurovascular evaluation. The contralateral lim b m ay be used as a n orm al com parison if it is asym ptom atic. Furth er testin g for specific disorders is added to th e exam in ation depending on clinical suspicion. These tests will be further discussed in the section s on the path ologic entities th at th ey detect. As previously stated, there is significant overlap between cervical spin e an d upper extrem ity disorders, an d th ey can frequently occur sim ultaneously. Prior to exam ination of th e extrem ity, a com plete cervical spin e exam in ation is n ecessary. Ran ge of m otion , ten dern ess, an d th e presence of a Spurlin g or Leh rm ite sign are n oted. In addition , a com plete sh oulder exam in ation will h elp iden tify coexisting pathology.

Inspection Th e physical exam in ation begin s with a th orough circum ferential inspection. The location and character of traum atic woun ds, such as bruisin g or lacerations, are recorded.


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ligam en t is palpated alon g th e posterior h alf of th e radial h ead. Movin g posteriorly, th e olecran on bursa is exam in ed for tenderness, fluid, an d evidence of infection. The insertion of th e triceps is also exam in ed for ten dern ess. On th e m edial aspect of th e elbow, th e uln ar n erve is exam in ed for tenderness, subluxation, or a Tinel sign . Th e m edial epicon dyle an d flexor pron ator m ass are palpated for ten dern ess, in dicative of m edial epicon dylitis. Last, palpate the an terior elbow, including the biceps tendon an d radial tun n el.

Figure 14.9 Cubitus varus. (Reproduced with permission from Beaty JH, Kasser JR. Rockwood and Wilkins’ Fractures in Children. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

An elbow joint effusion , indicative of intraarticular pathology, m ay be seen on th e lateral side of th e elbow between the radial h ead and the olecranon. Any asym m etric m uscle atrophy should raise the con cern of chronic denervation. The presence and location of any prior surgical incisions is also important. O pen woun ds, drainin g sin uses, an d warm th and erythem a should be considered as possible eviden ce of in fection. Elbow align m en t is also evaluated. Th e carryin g an gle, form ed between th e h um erus an d forearm , should be 5 to 7 degrees of valgus. Asym m etry is m ost com m on ly seen following pediatric traum a to the supracon dylar h um erus (Fig. 14.9).

Palpation Careful palpation of all structures is perform ed. The elbow offers an advan tage durin g physical exam in ation in that m any structures are subcutaneous and readily palpable even in obese patien ts. Th is is a diagn ostic exam in ation and should be conducted circum ferentially so as not to m iss any poten tial problem areas. Begin n in g on th e lateral side, palpate th e lateral epicon dyle. Ten dern ess is in dicative of lateral epicon dylitis. Th e radial h ead is palpated an d can be felt rotating un derneath the skin with forearm pron ation an d supin ation . An effusion m ay be palpated in the triangular area between the lateral epicon dyle, radial head, and proxim al tip of th e uln a. The lateral collateral

Range of Motion Th e elbow is capable of flexion , exten sion , pron ation , an d supin ation. Th e functional range of m otion has been determ in ed to be a flexion –exten sion arc of 30 to 130 degrees an d pron ation an d supin ation of 50 degrees each . Th e passive an d active ran ge of all four m otion s is exam in ed and recorded. The contralateral elbow, if uninvolved, can be used as a com parison . Any crepitus, clickin g, or grin ding during range of m otion should be noted. If lim itations in m otion exist, the firm ness of th e endpoint should be n oted. A soft endpoin t m ay be m ore in dicative of soft tissue con tracture that m ay improve with stretching, whereas a m ore firm en dpoin t m ay in dicate a process less likely to resolve with n on operative treatm en t, such as a syn ostosis. Th e presen ce of pain durin g ran ge-of-m otion exam in ation can also be in form ative. Pain durin g th e m idran ge as opposed to th e en d ran ge of m otion m ay in dicate abn orm ality of the joint surface in stead of surrounding soft tissue path ology. Stability Assessm en t of stability of th e elbow is often difficult for two reasons. One, instability is often very painful and patients will guard against attempts at recreating the unstable scen ario. Secon d, sh oulder m otion m ust be controlled so th at varus an d valgus stressin g of th e elbow is n ot falsely positive sim ply because th e h um erus is rotatin g. Th ere are specific tests for differen t types of instability, wh ich will be discussed in th eir respective section s later. Neurovascular Assessment A th orough neurovascular exam in ation is un dertaken. Th e radial, m edian , uln ar, an d several cutan eous n erves cross th e elbow an d m ay be subject to traum atic or surgical in jury or atraum atic n europathy from compression . Neural exam in ation sh ould in clude m uscle stren gth testin g and sensory exam ination. Strength testin g sh ould be conducted m eth odically an d sh ould in clude all four m otion s of th e elbow. Sen sory testin g sh ould in clude ligh t touch an d two-point discrim ination for greater accuracy. Knowledge of cervical root in n ervation an d periph eral n erve in n ervation is crucial for delineating the location of potential lesions. For example, elbow extension by the triceps in in n ervated by th e radial n erve periph erally an d th e seventh

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cervical root centrally. This m ust be taken into account so that a weak triceps is n ot m isdiagn osed as a radial nerve in jury wh en it is in fact a cervical lesion . Com parison of m otor testin g with any sen sory deficits can h elp n arrow th e location of th e lesion . Th e vascular exam in ation sh ould start above th e elbow with palpation of th e brach ial artery an d followed down the arm into the wrist with palpation of th e radial and poten tially th e ulnar artery. Comparison with the contralateral side and pulse differences with elevation or position in g m ay be eviden ce of vascular com pression such as th oracic outlet syndrom e.

Imaging

delin eate osseous structures, an d it offers m ultiplan ar im aging that plain radiograph s do not. It is an excellent m odality for evaluating the three-dim ensional configuration of fractures. MRI with or with out an arthrogram can evaluate distin ct soft tissues such as collateral ligam en ts and the biceps tendon. Soft tissue n eoplastic processes are best evaluated with MRI. A com bin ation of MRI an d CT is typically used for diagnosis and evaluation of osseous tum ors. US is a con stantly improving im aging m odality th at is being used m ore com m only in the evaluation of a great deal of elbow path ology. It is a relatively in expen sive an d n onin vasive study with th e down side th at it is h ighly operator depen den t.

Im agin g m akes up th e th ird step in th e evaluation of elbow disorders. Th e m ost com m on im agin g m odalities in use are plain radiograph s, m agn etic reson an ce im agin g (MRI), computed tom ography (CT), and ultrasound (US). After a thorough history and physical exam ination, im aging studies can often h elp con firm a diagn osis eith er th rough a positive fin din g or by elim in atin g an item from th e differen tial diagn osis. Im agin g studies can be m isleadin g, h owever, if viewed with out con siderin g th e h istory an d physical exam in ation . Im agin g studies are m ost effective wh en used to confirm a suspected diagn osis from the history and physical exam in ation . For example, a CT scan m ay be used to iden tify th e exact size an d location of a coron oid fracture, which will poten tially alter m an agem ent. Im aging studies are less effective wh en used as a “sh ot in th e dark,’’ such as obtain in g an MRI, lookin g for any path ology to explain vague symptom s.

Synovial Fluid/Laboratory Studies

Radiography Plain radiograph s rem ain th e in itial im agin g study for virtually all disorders of th e elbow. A stan dard series in cludes anteroposterior (AP), lateral, an d oblique views (Fig. 14.10). Addition al radiograph s such as radiocapitellar, traction , or stress views are obtain ed, depen din g on the condition under investigation . Radiographs are relatively in expen sive an d n on in vasive an d can provide a large am oun t of in form ation . Astan dard radiograph ic series will often give m ore in form ation about con dition s such as fractures, arth ritis, an d an gular deform ities th an any advan ced im agin g m odality. Radiograph s m ust be scrutin ized for th e presen ce of osseous lesion s or soft tissue swellin g con sisten t with a n eoplastic process. Th ey also m ust be scrutinized for m ultiple injuries. It is easy to m ake the m istake of iden tifyin g th e prim ary abn orm ality on th e radiograph an d th en m issin g an addition al in jury th at m ay n ot be as obvious.

Fractures of the Humeral Shaft Fractures of th e h um eral sh aft com e in m any varieties. Th ey are seen in all age groups followin g both low- and highen ergy m ech an ism s of in jury. Most h um eral sh aft fractures will h eal with n on operative treatm en t. Th ere are, h owever, certain absolute and relative indications for operative fixation .

Additional Imaging Additional im aging m ay be added to the diagnostic arsenal dependin g on the pathology in question . CT scan will

Depen din g on th e path ology in question , laboratory work an d syn ovial fluid an alysis can be very ben eficial. Th e workup for infection often includes a complete blood cell coun t, eryth rocyte sedim en tation rate (ESR), an d C-reactive protein (CRP). Synovial fluid is exam ined for the white blood cell (WBC) count, Gram stain, an d culture. If concern exists, fungal and viral cultures an d acid-fast bacillus (AFB) testin g m ay also be added. Laboratory and synovial fluid analysis are also useful in the workup of in flam m atory arthritis and crystalline arthropathies.

TRAUMATIC INJURIES TO THE ELBOW Fractures

Classification Fractures of th e h um eral sh aft are gen erally classified by location and fracture type. The location is described as m idsh aft, junction of th e m iddle and distal third, or junction of th e proxim al an d m iddle th ird. Th e fracture type is described as transverse, oblique, spiral, or com m inuted. The presen ce of a butterfly fragm en t or a segm en tal compon en t is also noted. Mechanism of Injury Th e m ech an ism of in jury of h um eral sh aft fractures m ay vary widely. A young patien t with good bon e stock will often presen t followin g h igh -velocity traum a. Altern atively, activities that place high torsional force on the arm , such as


A

Figure

559

B

14.10 Anteroposterior (A),

oblique (B), and lateral (C) radiographs of elbow.

C

arm wrestling, m ay also lead to fracture. An elderly patient m ay only have h ad a ground-level fall. Last, a direct blow, such as following an assault, m ay lead to a hum eral sh aft fracture. The fracture pattern will often give clues to the m echanism of injury. Spiral fractures, for example, are com m on from torsional in juries, whereas com m inuted, transverse fractures are caused by h igh er energy traum a. Un usually low-energy injuries and patients with preexistin g arm

pain or con stitution al symptom s sh ould raise con cern for the presence of a pathologic fracture. Presentation Patients will present with pain , swelling, and varying degrees of deform ity. They will h ave pain with attempts at elbow or sh oulder m otion an d will be com forted with support un der th e arm or slin g im m obilization .

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Figure 14.11 Internal rotation and

A

Physical Findings Th e skin will often display eviden ce of traum a, such as bruisin g an d ecchym oses, particularly in h igh er en ergy in juries. Open h um eral sh aft fractures are relatively un com m on , secon dary to th e large soft tissue en velope, but th e skin m ust be thoroughly exam ined such that an open injury is n ot m issed. A careful n eurovascular exam in ation sh ould be perform ed and docum en ted, with specific atten tion placed on distal exam in ation of th e radial n erve. Th e n erve run s alon g th e posterior h um eral sh aft in th e spiral groove and m ay be injured durin g or after fracture. Radiographic Evaluation Radiograph s of th e h um eral sh aft m ust in clude two orthogon al views th at are taken 90 degrees to one another. Th e radiological tech n ologist will often attempt to take two orth ogon al views by takin g two AP views, on e with the hum erus in ternally rotated an d one externally rotated (Fig. 14.11). Th is will on ly lead to m otion th rough th e fracture site an d in adequate radiograph s. Atran sth oracic lateral is an altern ative m eth od to obtain a view th at is orth ogon al to th e AP. It is also crucial th at th e radiograph s in clude th e elbow an d sh oulder to iden tify th e presen ce of any articular exten sion or addition al in jury to th ese adjacen t structures. Special Studies Furth er studies are rarely required for th e evaluation of hum eral sh aft fractures. A CT scan m ay help determ in e the presence an d degree of involvem ent of the shoulder or elbow join t if th ere is a con cern for articular exten sion .

B

external rotation views of the humerus attempting to obtain two orthogonal views. Rotation occurs through the fracture site leading to patient discomfort and inadequate radiographs.

Irregularity at th e fracture site th at suggests path ologic fracture should be further evaluated with advanced im aging such as MRI or bon e scan. An electromyogram (EMG)/ n erve conduction velocity (NCV) m ay be ordered if th ere is a neurologic deficit but is rarely helpful until several weeks following the injury. Differential Diagnosis Th e diagn osis of a h um eral sh aft fracture is rarely in question after the history, physical exam in ation, and radiograph s. Adjacen t join t in volvem en t an d path ologic lesion s sh ould be carefully elim inated from the differential diagn osis. Treatment Th e vast m ajority of h um eral sh aft fractures can be treated n onoperatively with predictably h igh rates of h ealing an d little residual deform ity. Initially, a coaptation splin t is applied from th e axilla to th e base of th e n eck, with a gen tle valgus m old (Fig. 14.12). When patien t com fort allows, th e splin t is con verted to a clam sh ell orth osis an d sh oulder an d elbow m otion is in itiated. At 6 to 8 weeks, th e orth osis m ay be discon tin ued if th e physical exam in ation and radiographs dem onstrate healing. Up to 30 degrees of varus angulation and 3 cm of shortening is acceptable. Relative indications for surgical treatm ent include an inability to m aintain a closed reduction secondary to body habitus or th e presen ce of polytraum a with th e n eed for im m ediate use of th e extrem ity. Absolute in dication s for operative fixation include open fractures and those with vascular


A

561

B Figure 14.12 The majority of humeral shaft fractures are initially treated with a coaptation splint. This is converted to a clamshell orthosis once the discomfort for the initial injury subsides.

injuries. Plate fixation and intram edullary (IM) nailing have both been used successfully (Fig. 14.13). Plate fixation is m ore likely to cause radial n erve injury and elbow stiffness, wh ereas IM nailing is m ore likely to cause shoulder pain from en try th rough th e rotator cuff an d is associated with a higher incidence of nonunion. The presence of a radial n erve palsy at th e tim e of in jury does n ot n ecessitate operative fixation . In th e absen ce of sh arp, pen etratin g traum a, the nerve injury m ay be observed, as m ost injuries are neuropraxia with predictable recovery. Failure of recovery by 3 to 4 m on th s m an dates furth er in vestigation with possible surgical exploration .

Fractures of the Distal Humerus Fractures of th e distal h um erus represen t a large spectrum of in juries varyin g widely in complexity, treatm en t, an d progn osis. Th ey occur in all ages, an d treatm en t is depen den t on factors such as fracture pattern , activity level, an d bon e quality. Classification Th e Orth opaedic Traum a Association system is curren tly the m ost comprehensive and reproducible classification sch em e for fractures of the distal hum erus. Extraarticular fractures are labeled as type A, partial articular fractures (m edial, lateral, an terior) as type B, and complete articular fractures as type C. Furth er breakdown of the classifica-

tion is based on th e presen ce of m etaphyseal an d articular com m in ution (Fig. 14.14). Mechanism of Injury Fractures of th e distal h um erus occur in a bim odal distribution . Youn ger patien ts usually require a large force to fracture th e bon e, such as a h igh -speed m otor veh icle collision , wh ereas older patien ts m ay sustain a fracture simply from a fall from standing height. In both groups, the m echanism of in jury is usually a direct axial load on a flexed elbow. Presentation Patients will present with pain, swelling, and deform ity at th e elbow followin g traum a. Th e elbow will be h eld at the side, and any attempted elbow m otion will be painful. O ften a splin t will h ave been placed by param edics or an oth er physician prior to orth opaedic evaluation . Physical Findings As with any fracture, th e skin m ust be exam in ed carefully for any wound th at m ay be evidence of an open fracture. Any splin t or dressing m ust be completely rem oved such that a thorough exam ination m ay be undertaken. A careful n eurovascular exam in ation is perform ed n ext. Th e uln ar n erve is n ear th e m edial epicon dyle an d requires special atten tion . In terosseous m uscle m otor stren gth an d sen sation to th e sm all an d uln ar side of th e rin g fin ger m ust be

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A,B

C Figure 14.13 (A) Preoperative radiograph of a displaced humeral shaft fracture. (B and C) Postoperative radiographs demonstrating open reduction and internal fixation with a plate and screws.

A

C1

B

C2

C

C3

Figure 14.14 Orthopaedic Trauma Association classification of distal humerus fractures. (Reproduced with permission from Bucholz RW, Heckman JD, Court-Brown C, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA; Lippincott Williams & Wilkins, 2005.)


docum en ted. A secon dary survey for un diagn osed in juries sh ould be perform ed, particularly in high-velocity traum a or un con scious patien ts.

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Differential Diagnosis Th e diagn osis of distal h um eral fractures is typically obvious on plain radiograph s. In the absence of fracture on radiograph , soft tissue in juries such as an elbow dislocation or ligam en t rupture m ust be con sidered. Fractures in oth er areas of th e elbow, such as th e olecran on , sh ould also be con sidered in th e differen tial diagn osis.

essen tially n on displaced fractures wh o can with stan d gen tle early m otion and those with m edical com orbidities th at place th em at excessive surgical risk. O perative treatm ent is favored in m ost patients. In younger patients, open reduction an d in tern al fixation (ORIF) is recom m en ded (Fig. 14.16). The goals of surgery are to restore the articular con gruity an d obtain stable in tern al fixation th at will allow early m otion . Failure to restore th e join t surface m ay lead to posttraum atic arthrosis, which is difficult to treat in the younger population. Osteotomy of the olecranon m ay be n ecessary for improved exposure of th e join t surface, in the presen ce of com m in ution . Stiffn ess an d h eterotopic ossification (HO ) form ation are com m on complications following ORIF. Elderly patients with osteoporosis will often h ave sign ifican t fracture com m in ution an d a low-dem and lifestyle. Obtaining stable intern al fixation m ay not be possible. Wh en ever possible, ORIF is the preferred treatm ent for distal hum erus fractures in the elderly. However, if poor bon e quality preven ts prim ary O RIF, acute total elbow arth roplasty (TEA) is the preferred treatm en t. The m ost con cern in g com plication of TEA is th e developm en t of in fection. Because of the lim ited soft tissue envelope around th e elbow, in fection rates reach as h igh as 5%, substan tially h igh er th an other joint arth roplasties.

Treatment Th e treatm en t of distal h um erus fractures depen ds on m any factors. The elbow joint is prone to stiffn ess and im m obilization m ust be kept to a m inim um . Nonsurgical treatm ent, therefore, is indicated only for patients with

Fractures of the Radial Head Fractures of the radial head are relatively com m on injuries about th e elbow. They m ay occur in isolation or in association with oth er bony or soft tissue in juries. Th ere are m ultiple treatm ent options depending on th e fracture type.

Radiographic Evaluation Th e stan dard series of plain radiograph s in cludes AP, lateral, an d oblique views of th e elbow. If th ere is sh orten in g of th e bon es with overlappin g segm en ts, gen tle traction can be applied to th e elbow wh ile radiograph s are taken . Special Studies In a simple fracture pattern , plain radiograph s m ay be sufficient for diagnosis, classification , and treatm ent. A CT scan is a very useful additional study and should be obtain ed if there is any question as to th e location of the fracture fragm ents or degree of complexity (Fig. 14.15).

Classification Radial h ead fractures are classified accordin g to Mason (Fig. 14.17). Type I fractures are n ondisplaced. Type II fractures have a m arginal fracture or impaction but have a portion of the head that is not fractured. Type III fractures are com m inuted and involve th e entire radial head. A type IV fracture was later added to th e classification to in clude radial h ead fractures with an associated elbow dislocation . Mechanism of Injury Fractures of th e radial head usually occur followin g a fall on to th e outstretch ed h an d. Th e force is tran sm itted th rough th e forearm in to th e elbow. Wh en an elbow dislocation has occurred, the radial head m ay be fractured by th e distal h um erus as it exits th e join t.

Figure 14.15 A coronal computed tomography reconstruction

demonstrating a distal humerus fracture with articular displacement.

Presentation Patien ts presen t with variable degrees of pain depen din g on th e exten t of in jury. Min im ally displaced fractures m ay cause little pain with ran ge of m otion an d presen t m uch like a bruise or sprain. More displaced fractures will cause sign ificant pain , an d the patient will be reluctan t to m ove th e elbow.

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A

B

C

D Figure 14.16 Pre- (A and B) and postoperative (C and D) radiographs of a distal humerus fracture

treated with open reduction and internal fixation. An olecranon osteotomy was performed to improve visualization of the articular surface during reduction. This was repaired with a precontoured proximal ulna plate.

Physical Findings Th e radial h ead is con sisten tly palpable alon g th e lateral aspect of th e elbow, even in obese patien ts. Th e exam in er can feel for tenderness over the radial head as it is rotated with forearm pronation an d supination. An effusion m ay be palpable in th is area as well. Ran ge of m otion is a crucial

com pon en t of th e physical exam in ation , as any block to m otion th at is not secondary to pain is an indication for surgery. Aspiration of th e hem arthrosis followed by injection of local anesthetic in to the join t will provide pain relief so th at the ran ge of m otion can be assessed (Fig. 14.18). A careful wrist exam in ation is perform ed to determ in e th e


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n um ber an d location of fragm en ts. It m ay also h elp diagn ose oth er path ology, such as coron oid fractures, n ot seen on plain radiograph . Differential Diagnosis Displaced radial h ead fractures will be seen on plain radiograph . Non displaced fractures, h owever, m ay dem on strate on ly a posterior fat pad sign , or an effusion , on radiograph s. Oth er causes of in traarticular path ology, such as occult fracture or ligam en tous in jury, m ust be ruled out in th is in stan ce. A careful physical exam in ation is perform ed and radiographs and advanced im aging are scrutinized for th e presen ce of th ese oth er in juries. Figure 14.17 The Mason classification of radial head fractures.

(Reproduced with permission from Koval KJ, Zuckerman JD. Handbook of Fractures. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

presen ce or absen ce of an Essex–Lopresti lesion. This is a longitudinal in jury that begins at the distal radiouln ar joint an d propagates along the interosseous m em brane, finally en din g at th e radial h ead. Th is is a m ore com plex in jury than an isolated radial h ead fracture and its presence m ay significantly alter m anagem ent. Radiographic Evaluation Th e diagn osis is typically m ade from plain radiograph s. A plain radiograph ic series in cludes AP, lateral, an d oblique views. A radiocapitellar view is a lateral view of the elbow with an oblique an gle to m in im ize overlap between th e radial h ead an d th e proxim al uln a. Th is can give a m ore complete view of th e proxim al radius. Special Studies If furth er defin ition of th e fracture is n ecessary, a CT scan is obtained. It can give valuable in form ation regarding the

Treatment Fractures with less than 2 m m of displacem ent are treated n on operatively. Th e elbow is im m obilized briefly in a sling for com fort, and early m otion is begun when the patient is able to tolerate it. The elbow should n ot be used for strenuous activities un til 6 weeks after in jury wh en a gradual increase in weight-bearing is allowed. Fractures with m ore sign ificant articular displacem ent or an osseous block to m otion are treated with ORIF or radial head replacem ent. Youn ger patien ts with sim pler fracture pattern s are treated with ORIF (Fig. 14.19). Older, seden tary patien ts or th ose with com m in uted fractures are treated with radial h ead replacem en t. Postoperative early m otion is again critical to reduce stiffn ess. Associated in juries m ust be assessed such th at early m otion is lim ited to a safe an d stable zon e. Partial or complete radial head excision m ay be considered in rare circum stan ces but m ust n ot be perform ed if an Essex– Lopresti lesion is presen t. In gen eral, a radial h ead replacem ent is favored to prevent proxim al m igration of the radius.

Fractures of the Olecranon Fractures of the olecranon present following several different injury m echanism s an d with several different fracture patterns. The olecranon m akes up the ulnar side of th e uln oh um eral join t an d fractures th rough th e area are intraarticular, wh ich affects m anagem ent. The olecranon also serves as the attachm en t site for the triceps tendon and fractures will usually disrupt th e exten sor m echanism of th e elbow. Classification Fractures of the olecran on are classified according to th e am ount of displacem ent and the presence or absence of com m in ution . Fractures are un displaced, displaced with a stable uln oh um eral join t, and displaced with an unstable uln oh um eral join t. For each fracture type th ere are n on com m in uted an d com m in uted subgroups (Fig. 14.20).

Figure 14.18 The elbow can be aspirated via the lateral soft

spot, which is located at the center of a triangle formed by the lateral epicondyle, radial head, and olecranon. (Reproduced with permission from Bucholz RW, Heckman JD, Court-Brown C, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)

Mechanism of Injury Fractures of th e olecranon typically occur through two different m echan ism s. O ne type of fracture is an avulsion of th e triceps m ech an ism , wh ich is typically a tran sverse

A

B

Figure 14.19 (A) Pre- and (B) postoperative radiographs of open reduction and internal fixation of a radial head fracture.

Figure 14.20 Mayo classification of olecranon frac-

tures. (Reproduced with permission from Bucholz RW, Heckman JD, Court-Brown C, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)

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fracture with m inim al com m inution. Th e second type of fracture occurs from a direct axial load onto the flexed elbow. Varyin g degrees of com m in ution an d articular impaction m ay be present. Presentation Presen tation will vary depen din g on th e m ech an ism of in jury an d severity of th e fracture. Patien ts will h ave pain , ten dern ess, an d swellin g about th e proxim al uln a. Th ey will h ave pain with attempted ran ge of m otion . Physical Findings Th e status of th e exten sor m ech an ism of th e elbow m ust be evaluated. In ability to fully exten d th e elbow again st gravity is an indication for operative treatm ent. Th e skin overlying the proxim al uln a m ust be carefully exam ined for open woun ds, as th e m ajority of th e bon e is subcutan eous an d an open fracture cannot be overlooked. As always, a careful neurovascular exam in ation is undertaken with particular attention to the ulnar nerve because of its close proxim ity to th e olecran on . Radiographic Evaluation Plain radiograph s are typically sufficien t for diagn osis. Th e three standard views of the elbow are obtained. The lateral view will dem on strate th e degree of displacem en t, th e stability of th e uln oh um eral joint, an d the presence of com m inution. Special Studies CT scan can be useful if concern for articular com m inution or im paction exists. It m ay also be h elpful to determ in e

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wh eth er th ere is exten sion of th e fracture in to th e coron oid process. Differential Diagnosis If plain radiograph s do n ot reveal any osseous abn orm ality, oth er soft tissue in juries m ust be con sidered. Rupture of th e distal triceps will h ave a sim ilar presen tation as olecran on fractures, with loss of elbow extension . Injury to the m edial or lateral ligam en ts m ust also be evaluated. Treatment Th e treatm en t of olecran on fractures depen ds on th e fracture pattern and patient factors. With fracture displacem ent of less th an 2 m m an d full-elbow exten sion again st gravity, nonoperative treatm ent is indicated. A short period of im m obilization followed by early m otion is in stituted. Exercises sh ould be lim ited to active flexion an d passive exten sion to reduce th e pull of th e triceps again st th e fracture. If significan t displacem ent exists or triceps fun ction is comprom ised, operative treatm ent is favored. Simple fracture patterns m ay be treated with tension ban d wiring (Fig. 14.21), whereas plate fixation is required if significant com m in ution or im paction is presen t. In elderly patien ts with com m in uted fractures, resection of th e fracture with reattach m en t of th e triceps can be perform ed. At least 50% of th e olecran on m ay be excised with out comprom isin g elbow stability, provided th e m edial an d lateral collateral ligam ents are intact.

Fractures of the Coronoid Th e coron oid process acts to buttress again st posterior translation of the ulna on the hum erus. It also serves as the attachm ent site for the anterior elbow capsule, the

A

B Figure 14.21 Tension band wiring of an olecranon fracture. (Reproduced with permission from

Bucholz RW, Heckman JD, Court-Brown C, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)

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with radial h ead fractures. As th e distal h um erus subluxes an teriorly, th e coronoid is subjected to sh earing forces th at can lead to fracture. Coronoid fractures are also seen as the exten sion of a complex proxim al uln a fracture, such as th e transolecranon fracture dislocation.

Figure 14.22 Regan and Morrey classification of coronoid frac-

tures. (Reprinted with permission from Regan W, Morrey BF. Fractures of coronoid process of the ulna. J Bone Joint Surg Am. 1989;71:1348–1354.)

brach ialis, an d th e m edial collateral ligam en t. Fractures of the coron oid are often seen in conjun ction with oth er injuries to th e elbow, such as dislocation s. Classification Fractures of th e coron oid are classified accordin g to Regan an d Morrey (Fig. 14.22). A type I fracture in volves just th e tip of th e coron oid. Type II an d type III fractures in volve less than 50% or greater than 50% of the coronoid, respectively. Recen tly, m ore focus h as been placed on th e im portan ce of the location of the fracture. The anterom edial facet plays a key role in elbow stability an d is th e basis for th e O’Driscoll classification (Fig. 14.23). Mechanism of Injury Coron oid fractures are frequen tly seen in th e settin g of acute elbow in stability, m ost com m on ly a posterior elbow dislocation . Coron oid fractures are frequen tly associated

Tip Anteromedial

Basal

Figure 14.23 O’Driscoll classification of coronoid fractures. (Reproduced with permission from Bucholz RW, Heckman JD, CourtBrown C, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)

Presentation Th e patien t’s h istory will often give clues to th e diagn osis. Patien ts m ay describe a subluxation of the elbow that self-reduced. If th e patient reports that a closed reduction was required, a coronoid fracture sh ould be considered. Patients will have diffuse pain and swelling and be reluctant to m ove th e elbow. Physical Findings After a careful neurovascular exam in ation an d close evaluation of th e skin in tegrity, a ran ge-of-m otion an d stability exam ination is perform ed. Stability is often difficult to evaluate secon dary to pain an d guardin g. An exam in ation un der an esth esia is con sidered if furth er in form ation is n eeded. Radiographic Evaluation Plain radiograph s con sistin g of th ree views of th e elbow are obtain ed in itially (Fig. 14.24). Fractures of th e coron oid m ay be very sm all and the radiographs m ust be closely scrutin ized. While fran k dislocations will be obvious, subtle subluxation m ust not be overlooked. Special Studies Coronoid fractures m ay be difficult to appreciate on plain radiograph s secon dary to overlap of th e radial h ead an d oth er bony structures. CT scan s are very h elpful in th ese cases where the size and configuration of th e fracture rem ain s in question (Fig. 14.25). Differential Diagnosis Th e differen tial diagn osis of coron oid fractures in cludes oth er osseous an d soft tissue in juries of th e elbow. Dislocation of th e elbow, radial head fracture, and olecranon fracture m ust be considered. Treatment Th e m an agem en t of coron oid fractures depen ds on m ultiple factors. Fractures of th e tip of th e coron oid h ave traditionally been considered capsular avulsions from an elbow dislocation . In reality, th e tip of th e coron oid is in traarticular and th e capsule inserts m ore distal so these likely represent sheer in juries. Th ese isolated fractures can be m anaged n on operatively as lon g as a con cen tric reduction of the elbow can be m ain tain ed durin g early con trolled m otion an d associated injury to th e radial head does not require surgical m an agem ent. If repair is required, the fragm ent is often too sm all for ORIF an d suture repair of th e overlyin g capsule down to the ulna is perform ed. Larger fractures will con tribute m ore to elbow stability and m ay require ORIF.


A

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B

Figure 14.24 Plain lateral (A) and oblique (B) radiographs of a Type II coronoid fracture.

Fractures of th e an terom edial facet, in particular, lead to varus posterom edial in stability. Restoration of the coronoid buttress with screw or plate fixation is often n ecessary to ach ieve stability of th e elbow (Fig. 14.26). O ften tim es, the lateral soft tissues of the elbow will be disrupted as well. Th e treatm en t of oth er in juries associated with elbow instability is discussed later.

Instability Elbow Dislocation Dislocation of th e elbow is a relatively com m on in jury, m aking up as m any as 25% of all elbow injuries. They typically occur in youn ger patien ts, often durin g con tact sports or activities. Associated in juries are com m on an d play a m ajor role in th e m anagem ent of elbow dislocations.

A Figure 14.25 Lateral (A) and three-dimensional (B) computed tomography scan reconstructions of a coronoid fracture.

B

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associated fractures, whereas complex elbow dislocations will h ave associated fractures of th e radial h ead, coron oid process, or distal h um erus. Mechanism of Injury Th e vast m ajority of elbow dislocation s are posterior. Th ey typically occur from a fall onto an outstretched arm . O’Driscoll has proposed that elbow dislocations begin with failure of th e lateral tissues, specifically th e LUCL. As th e force dissipates, the capsule continues to tear anteriorly and posteriorly an d ultim ately th e m edial ligam en tous structures are disrupted.

Figure 14.26 Open reduction and internal fixation coronoid.

(Reproduced with permission from Bucholz RW, Heckman JD, Court-Brown C, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)

Classification Elbow dislocation s are classified first accordin g to the direction of th e dislocation (Fig. 14.27). Stan dard orth opaedic nom enclature describes a dislocation based on the location of th e distal segm en t in relation to th e proxim al segm en t. A posterior elbow dislocation , for example, implies that the forearm lies posterior to the hum erus. They are further classified on the basis of th e presence of associated in juries. Simple elbow dislocation s do n ot h ave any

Presentation Patients will presen t with acute pain, deform ity, and inability to ran ge the elbow. Th ey will typically hold the arm at the side with the elbow partially flexed. Physical Findings A careful n eurovascular exam in ation prior to any reduction m aneuver is critical in th e initial evaluation. The exam in ation m ust be repeated followin g reduction, as n erve en trapm en t with in th e join t h as been reported. Alth ough rare, compartm en t syn drom e does occur an d m ust be diagnosed an d em ergently treated. Radiographic Evaluation Plain radiograph s will clearly dem on strate a dislocated elbow. Th e presen ce of associated fractures m ay n ot be as obvious. Postreduction radiograph s m ay be m ore h elpful in the diagn osis of oth er injuries. Th ey should be evaluated to en sure that there is not an in carcerated fragm ent of bon e with in th e join t. Any residual subluxation m ust be identified and treated accordin gly. Special Studies As stated earlier, a CTscan is obtained if a coronoid or radial h ead fracture requires furth er evaluation . Rarely, an MRI m ay be useful in determ ining the extent of ligam entous injury. Differential Diagnosis Th e differen tial diagn osis of elbow dislocation s in cludes fractures of the distal hum erus, olecranon, and radial head. Plain radiograph s will rule out th ese oth er in juries. Treatment Simple Elbow Dislocation. Th e in itial m an agem en t of an

Figure 14.27 Classification of elbow dislocations. (Reproduced

with permission from Browner BD, Jupiter JB, Levine AM, eds. Skeletal Trauma. Philadelphia, PA: WB Saunders, 1992:1142.)

elbow dislocation is a gen tle reduction m an euver. After the induction of appropriate sedation, gentle traction and countertraction are applied. Th e elbow is slightly extended to allow th e coron oid to be brough t back an terior to th e hum erus. Th e elbow is exam in ed to determ in e stability wh ile th e patien t is still an esth etized. Postreduction radiograph s are obtain ed to en sure a con cen tric reduction . A short period of im m obilization is followed by controlled


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early m otion . If th e elbow is un stable m ovin g in to th e exten ded position , a h in ged brace is utilized. Th e brace is set to lim it exten sion within stable lim its for the first few weeks. It is gradually open ed an d discon tin ued between 3 an d 6 weeks, depen din g on th e stability exam ination . In elbows th at are m ore un stable an d can n ot be treated closed, open repair is in dicated. Operative treatm en t begin s with repair of th e LUCL. Stability is reevaluated an d if in stability persists, repair of th e MUCL is con sidered. Last, a h in ged extern al fixator m ay be placed if residual in stability exists.

across th e elbow durin g overh ead th rowin g. For overh ead ath letes, in jury to th e MUCL is a very disablin g an d poten tially career en din g in jury. Many profession al ath letes h ave h ad th eir careers cut sh ort by th is in jury, wh ich m ay explain th e atten tion it receives in th e m edia.

Complex Elbow Dislocation. Associated fractures with an

Mechanism of Injury Th ere are two prim ary m ech an ism s of in jury to th e MUCL. A sin gle even t such as an elbow dislocation or acute valgus load m ay rupture th e ligam en t. Th e force across th e elbow durin g a pitch far exceeds th e stren gth of th e ligam en t. More com m only, repetitive traum a from overh ead activities will lead to atten uation an d ligam en t in sufficien cy.

elbow dislocation suggest th at th e elbow m ay be un stable following reduction, m akin g closed treatm ent m ore unpredictable. An elbow dislocation with a radial h ead an d coron oid fracture, known as the terrible triad, is best treated surgically. Th e lateral side of th e elbow is addressed first. Th e radial head is fixed or replaced depending on the fracture. The coronoid fracture can often be approached through a lateral in cision on ce th e radial h ead h as been resected prior to replacem en t. However, a separate m edial approach is n ecessary for larger an d m ore m edial fragm en ts or if th e radial head fracture does not perm it adequate exposure. The LUCL is repaired as part of th e closure. If residual in stability is presen t, the MUCL is repaired. A h in ged external fixator is placed if th e elbow is still un stable.

Ligament and Tendon Injury Medial Collateral Ligament Th e an terior ban d of th e MUCL is th e prim ary restrain t to valgus stress on the elbow. High valgus loads are placed

Figure 14.28 The milking maneuver for evaluation of the medial ulnar collateral ligament. (Reproduced with permission from Morrey BF. Master Techniques in Orthopaedic Surgery: The Elbow. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2002.)

Classification In juries to th e MUCL are classified as acute versus ch ron ic ruptures. Th ey are further classified into m idsubstance tears an d bony avulsion s.

Presentation Th e h istory will often reveal th e m ech an ism of in jury. Patien ts presen t with m edial-sided elbow pain followin g an in jury or with certain activities. Som e patien ts will also complain of pain, num bness, and weakn ess in th e uln ar n erve distribution. Uln ar n erve symptom s are typically tran sien t occurrin g with th rowin g an d im prove on ce th rowin g is discon tin ued. Physical Findings Th e MUCL is exam in ed for ten dern ess to palpation . The m ilkin g m an euver places a valgus stress across th e elbow (Fig. 14.28). Th e m ovin g valgus stress test is a dyn am ic test

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that places a valgus stress across th e elbow while sim ulatin g a th rowin g m otion . Pain with eith er test is eviden ce of MUCL in sufficien cy. Th e uln ar n erve m ust be closely exam in ed for subluxation an d any sign of n erve dysfun ction . Th e lateral side of th e elbow m ust be exam in ed closely as well, as attenuation of th e MUCL m ay lead to h igher com pressive forces across th e radiocapitellar join t an d diseases such as osteochondritis dissecan s. Radiographic Evaluation A standard elbow series is obtained initially and m ay reveal a bony avulsion of the ligam ent. Valgus stress radiographs m ay dem on strate widen in g of th e m edial join t space. Special Studies An MRI arth rogram is the m ost sensitive and specific test for MUCL rupture. Concom itant path ology can also be diagn osed by MRI. Ultrason ography h as recen tly sh own prom ise in th e diagn osis of MUCL in jury, th rough n on in vasive m eans.

Differential Diagnosis MUCL insufficien cy m ust be distin guish ed from other causes of m edial-sided elbow pain . Medial epicon dylitis, cubital tun n el syn drom e, an d m edial epicon dyle fractures can present with symptom s sim ilar to MUCL injury. In skeletally im m ature ath letes, Little League elbow sh ould be con sidered. Radiograph s an d a careful physical exam in ation are usually sufficien t to m ake th e diagn osis. Treatment In itial treatm en t is typically con servative. Rest from in citing activities for up to 3 m onths is appropriate. Elbow ran ge of m otion an d stren gth en in g of th e flexor–pron ator m usculature are also initiated. On ce symptom s subside, th e patien t is gradually allowed to return to th rowin g. If th e patien t does n ot respon d to con servative treatm en t, surgical reconstruction is in dicated. Multiple reconstructive tech niques using different grafts and fixation m ethods h ave been described. Classically, autograft ten don is woven th rough bon e tun n els in th e h um erus an d uln a (Fig. 14.29). Use of allograft tissue an d fixation with in terferen ce screws

A

B

C Figure 14.29 Medial ulnar collateral ligament reconstruction. (Reproduced with permission from Morrey BF. Master Techniques in Orthopaedic Surgery: The Elbow. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2002.)


has been described m ore recen tly. An ulnar n erve tran sposition is n ot typically required wh en th e n erve sym ptom s are transient with activity. However, when the ulnar neuropathy is m ore profoun d, tran sposition m ay be required. Postoperatively, valgus stresses m ust be avoided. Early ran ge of m otion is in itiated in a h in ged brace. At 3 m on th s, early stren gth en in g is begun . Ligh t pitch in g from flat groun d begin s at 6 m on th s an d off th e m oun d pitch in g begin s at 9 to 12 m on th s.

Lateral Ulnar Collateral Ligament In jury to th e lateral ligam en tous structures of th e elbow has received increasing focus in th e recent literature. Insufficien cy of th e LUCL can lead to PLRI of th e elbow. Rupture of th e LUCL is n ow con sidered th e essen tial lesion in th e m ajority of elbow dislocations. Classification LUCL injuries are classified prim arily on the basis of ch ronicity of the injury. Associated injuries, such as radial head and coronoid fractures, are also docum ented. Mechanism of Injury Th e m ajority of LUCL in juries occur followin g subluxation or dislocation of th e elbow. After a fall on th e outstretch ed arm , the lateral ligam ents fail first. As the injury progresses an d the forearm rotates, th e force is carried across th e join t. Th e capsule tears an d even tually th e m edial ligam en ts fail (Fig. 14.30). Iatrogen ic in jury is an oth er cause of ligam ent comprom ise during procedures such as tennis elbow

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release. Th e LUCL is avoided durin g th e lateral approach to th e elbow by stayin g an terior to th e m idlin e of th e radial h ead. Overuse in juries are less likely to cause LUCL in jury but h ave been reported. Presentation Patien ts will presen t with lateral-sided elbow pain an d varying degrees of in stability. They will often give a history of a dislocation . Activities th at classically cause pain are th ose th at place a valgus load across a supin ated forearm as it m oves in to extension, such as rising from a chair using the arm rests. Physical Findings On physical exam in ation, patients will have tendern ess over th e lateral aspect of th e elbow. Th e pivot sh ift m an euver stresses the incompetent ligam ent complex (Fig. 14.31). With th e patient supine, the arm is elevated overh ead. The elbow is sligh tly flexed, th e forearm supin ated, an d a valgus and axial load is placed across th e elbow. This results in supination of the ulna away from the h um erus. The radial h ead follows th e uln a posteriorly. Th e elbow is slowly brough t in to flexion , an d th ere will be a palpable reduction of th e radial h ead. Th e m an euver is reversed, an d th e radial h ead is subluxed. A dimple in th e skin m ay be presen t over th e radial h ead. If prior surgery h as been perform ed, th e location of any previous in cision s sh ould be n oted as eviden ce of a possible iatrogen ic in jury. A subcutan eous fluid-filled cyst or a chron ic drain in g sin us followin g surgical treatm ent of lateral epicon dylitis is evidence of insufficiency of the lateral capsule and LUCL Radiographic Evaluation Plain radiograph s will reveal a dislocation or subluxation but are usually n orm al in cases of ligam en t in sufficien cy. Th e radial h ead sh ould poin t directly toward th e capitellum on all radiographic views. Fluoroscopic exam ination un der an esth esia will often reveal subluxation or dislocation in the provocative position s. US has been successfully reported as a diagn ostic test as well but is h igh ly operator depen den t. Differential Diagnosis Other causes of lateral-sided elbow pain are lateral epicon dylitis, radiocapitellar arth ritis, syn ovial plica, an d lateral epicon dylar fracture. Physical exam in ation an d im aging will help narrow the differen tial.

Figure 14.30 Progressive failure of the elbow ligaments with

dislocation of the elbow. (Reproduced with permission from Morrey BF. Master Techniques in Orthopaedic Surgery: The Elbow. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2002.)

Treatment Acute elbow dislocation m ay be in itially treated n on operatively, as stated earlier. In th e case of contin ued instability, acute ligam en t repair is usually sufficient to stabilize the elbow. However, ch ron ically un stable elbows require ligam ent reconstruction, not repair. Th e LUCL is reconstructed with autograft or allograft ten don . It is placed between th e

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A1

B1

A2

B2

A3

B3 Figure 14.31 The pivot shift maneuver for evaluation of the lateral ulnar collateral ligament.

(Reproduced with permission from Morrey BF. Master Techniques in Orthopaedic Surgery: The Elbow. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2002.)

lateral epicon dyle an d th e supin ator crest on th e uln a. Various fixation tech n iques h ave been described. Postoperative care includes early m otion in a safe range determ ined at surgery. Extension and supination are avoided. Varus stress across th e repair is also avoided, m ost com m on ly by keepin g th e arm at th e side. By 6 weeks, full m otion is allowed an d stretch in g is employed. Gradual in creased use of th e arm is perm itted over th e n ext 12 weeks an d stren gth en in g is added to th e postoperative regim en . Patien ts are allowed full activity at 6 m onths after surgery.

Distal Biceps Tendon Rupture Rupture of the distal biceps is a relatively uncom m on injury. O n ly 3% of biceps in juries in volve th e distal ten don insertion. Th e biceps m uscle is the prim ary supinator of the forearm and inserts on th e bicipital tuberosity of the radius. Th e distal ten don fibers un dergo degen eration with age, which likely predisposes patients to injury. Rupture of the tendon leads to loss of supination strength an d enduran ce. Flexion stren gth is also lost, but to a lesser degree given that th e brachialis rem ains intact.


Classification Distal biceps ten don ruptures m ay be partial or com plete. Complete ruptures are broadly classified into acute and ch ronic injuries. The definition of an acute rupture is arbitrary an d varies from less th an 2 to 6 weeks after in jury but gen erally is con sidered acute if th e in jury is less th an 4 weeks old. Mechanism of Injury Th e m ech an ism of in jury is typically an eccen tric load forcefully extendin g an actively flexing elbow. Presentation Ruptures of the distal biceps tendon prim arily occur in m en in their 50s. There have been a few reports of wom en sustain in g th is in jury. O th er risk factors in clude weigh tliftin g, steroid use, and sm oking. Patien ts m ay describe a tearin g sen sation and pain in the anterior elbow following an injury. Som e patien ts n ote a secon d distin ct tear th at represen ts failure of the bicipital apon eurosis. Physical Findings Patients with an acute rupture will have swellin g, ten derness, and ecchym oses around the proxim al m edial forearm . Th e biceps ten don will n ot be palpable alon g th e an terior elbow. Proxim al m igration of th e m uscle belly with supin ation m ay help confirm the diagn osis but m ay n ot occur if the lacertus fibrosis rem ains intact (Fig. 14.32).

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Radiographic Evaluation Plain radiograph s are usually n orm al but sh ould be scrutin ized for any abn orm alities of th e bicipital tuberosity. Special Studies MRI an d US h ave been used for con firm ation of th e rupture an d m ay dem on strate th e degree of proxim al m igration (Fig. 14.33). A special MRI view of th e biceps is obtain ed with the patient placed prone with the elbow flexed to 90 degrees, the shoulder abducted, and the forearm supin ated (FABS view). This view provides a longitudinal view of th e biceps ten don Differential Diagnosis Although rare, m uscle–ten don jun ction tears m ay occur an d will h ave a sim ilar presen tation . Oth er sources of path ology to con sider are partial ten don ruptures, cubital bursitis, an d lateral an tebrach ial n erve compression . Treatment Direct ten don repair to th e bicipital tuberosity is in dicated in active individuals to restore supination and flexion stren gth an d en duran ce. Non operative treatm en t is reserved for low-dem and patien ts or those who are m edically un fit for surgery. Multiple fixation m eth ods usin g eith er a one-incision or a two-in cision approach have been described. Historically, the one-incision technique had a high rate of radial nerve injury, leading to the developm ent of the two-incision repair. Recent advan ces in fixation using suture an chors an d fixation buttons have led to a renewed

A

B Figure 14.32 Clinical photographs demonstrating the right biceps with an intact tendon (A) and the left biceps where there is a distal biceps rupture (B).

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Th is leads to syn ovial hypertrophy an d pan n us form ation , wh ich is respon sible for th e ultim ate destruction of th e join t. Th e hyalin e cartilage surfaces are eroded in itially. Bone resorption an d soft tissue atten uation follow, leading to loss of the joint stability and arch itecture. The Mayo classification is based on radiograph s an d con sists of four grades th at closely m irror th e path ophysiology. Grade I represen ts syn ovitis, an d radiograph s are n orm al or m ay sh ow osteopen ia. Grade II dem onstrates join t space narrowin g con sisten t with loss of th e join t cartilage. Grade III disease dem on strates loss of join t arch itecture an d is furth er subdivided in to A or B, on th e basis of severity. Grade IV represen ts en d-stage disease with gross join t in stability, severe in con gruity, and extensive bone loss.

Figure 14.33 Sagittal magnetic resonance image demonstrating

a distal biceps rupture.

in terest in th e on e-in cision approach . Complication s with both approach es, in cludin g h eterotopic bon e form ation an d n erve dam age, rem ain a poten tial problem . Partial ten don ruptures are in itially treated con servatively. Failure to ach ieve relief of symptom s is an in dication for surgical treatm en t. Results h ave been prom isin g with th e completion of the partial tear and tendon reattachm ent. Chronic ruptures are a m uch m ore difficult problem to treat. Because of proxim al m igration of th e biceps ten don , ten don graft if often required an d results are m uch less predictable.

ATRAUMATIC CONDITIONS OF THE ELBOW Degenerative Joint Disease Sim ilar to oth er join ts in th e body, degen erative join t disease (DJD) of th e elbow occurs in several form s. It is typically classified in to osteoarth ritis (OA), posttraum atic arth ritis, an d in flam m atory arth ritis such as rh eum atoid disease. Each h as its own differen t ch aracteristics, but all can lead to substan tial disability.

Rheumatoid Arthritis With th e recen t adven t of disease-m odifyin g an tirh eum atic drugs, severe destructive elbow arth ritis is becom in g less com m on. RA, however, rem ains the m ost com m on cause of elbow join t arth ritis an d can be severely debilitatin g. Pathophysiology and Classification Autoim m une complexes form and incite a painful inflam m atory response in the synovial linin g of the joint.

Presentation Patien ts with early-stage disease will presen t with a pain ful ran ge of m otion an d join t effusion . In later stages, th ey will com plain of in creasin g loss of m otion an d varyin g degrees of join t deform ity. Patien ts h ave usually been diagn osed with RA prior to orth opaedic con sultation an d will often h ave adjacent joint or cervical spin e in volvem en t. Occasion ally, however, patien ts will present prior to diagnosis, and a proper workup or referral is imperative. Physical Examination An in itial in spection sh ould n ote any soft tissue swellin g, join t effusion , an d deform ity. Th e elbow is th en taken th rough a ran ge of m otion , n otin g any crepitus, grin din g, or in stability. Th e cervical spin e, sh oulder an d wrist are exam in ed, as well, for th e presen ce of any dysfun ction or deform ity. Radiographic Findings Th e radiograph ic fin din gs in rh eum atoid disease dem on strate the classic chan ges of inflam m atory arthritis. Periarticular osteopenia is seen in early stages. Sym m etric joint space n arrowin g and periarticular bone erosion follow. Ultim ately, bon e loss and soft tissue attenuation lead to loss of join t stability an d arch itecture. In con trast to OA, very few osteophytes are typically presen t. Special Tests Gen erally, th e plain radiograph s are sufficien t for diagn osis. CT scan s or MRI m ay be helpful if the degree of bone loss or soft tissue attenuation is in question . Laboratory workup for RA, such as rh eum atoid factor an d oth er in flam m atory m arkers, is con sidered if a diagn osis h as n ot yet been m ade. Differential Diagnosis RA is a form of inflam m atory arthritis, which can typically be distin guish ed from oth er form s of DJD by radiograph s. Oth er causes of in flam m atory arth ritis sh ould be con sidered, such as h em oph ilic arth ropathy an d psoriatic


A

577

B Figure 14.34 (A) Preoperative radiograph of an elbow with advanced rheumatoid arthritis. (B) Postoperative image following treatment with a total elbow arthroplasty.

arthritis. Patient history and laboratory workup will help distin guish th e differen t causes of in flam m atory arth ritis. Earlier stages of th e disease m ay be m ore difficult to diagnose, especially if the presentation is m onoarticular. In these cases, septic arthritis m ust be considered and on e m ust have a low threshold for aspiration of the join t. Treatment Early stages of RA can often be treated with m edication s, selective steroid injections, and activity m odification . Syn ovectomy, eith er open or arth roscopic, is con sidered if pain ful syn ovitis exists in a relatively well-preserved join t. Once joint destruction has reached end stages, TEA becom es th e m ost viable option (Fig. 14.34). Elbow replacem en t designs fall into two m ain categories. Linked implants offer im m ediate stability th rough a coupled articulation but h ave h igh er rates of loosen in g an d bush in g wear. Un linked implants have no physical linkage between the com pon en ts an d rely on th e n ative soft tissues for stability. Th ey typically h ave a lower rate of loosen in g but h ave a higher incidence of instability. Patien ts with RA typically have attenuated soft tissues, an d a lin ked implan t offers a m ore stability. Infection is a m ajor con cern following TEA an d can be as h igh as 5%. Any woun d complication m ust be taken seriously, an d prompt irrigation and debridem en t sh ould be un dertaken in attem pt to salvage th e prosth esis.

Osteoarthritis OAis relatively un com m on in th e elbow join t. Non eth eless, th e pain an d stiffn ess th at occur can greatly affect a patien t’s livelihood.

Pathophysiology and Classification OA is a poorly un derstood disease despite bein g th e m ost com m on cause of DJD th rough out th e body. It is likely th at m ultiple factors, includin g genetics and lifestyle, contribute to the form ation of OA. Patients whose jobs require h igh impact or repetitive traum a, such as using a jackham m er, seem to be at h igh er risk for the developm en t of elbow OA. Un like oth er join ts in th e body, the cartilage surface is initially spared in the elbow with OA. Abundant osteophytes form in the periarticular region , which lim it m otion. Even tually, the joint surface becom es involved and joint space n arrowin g occurs. Presentation Th e classic presen tation of elbow OA is loss of m otion with pain at term in al exten sion before term in al flexion . As th e elbow en ters th e en d ran ge of m otion , osteophytes cause a pain ful impin gem en t. Midran ge m otion , on th e oth er h an d, will typically n ot be pain ful, as th e join t surface is initially preserved. In later stages, however, as the joint surface becom es affected, m idran ge m otion will becom e m ore pain ful.

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resection . Total elbow replacem en t is rarely required in patients with OA.

Posttraumatic Arthritis Posttraum atic arthritis is an extrem ely difficult condition to treat. Because patien ts ten d to be youn ger, arth roplasty with lifelon g activity restriction s is an un realistic treatm en t option . Patien ts typically h ave a h igh -dem an d lifestyle an d require a fun ction in g elbow for th eir livelih ood.

Figure 14.35 Lateral radiograph of elbow osteoarthritis demonstrating significant periarticular osteophytes with preservation of the chondral surfaces.

Physical Examination Ran ge of m otion is th e m ost importan t compon en t of th e exam in ation of th e osteoarth ritic elbow. Th e overall ran ge is recorded first. Next, th e presen ce of pain durin g th e exam in ation is carefully evaluated. As stated earlier, th e presen ce of m idran ge pain im plies in volvem en t of th e join t surface which m ay sign ifican tly affect treatm ent. Radiographic Findings Plain radiograph s will reveal th e ch an ges of OA. In particular, periarticular osteophytes are often very impressive an d explain th e lack of m otion seen on physical exam in ation (Fig. 14.35). Join t space n arrowin g is typically not seen initially. The deform ity and instability seen with in flam m atory arth ritis is usually n ot seen with OA. Special Tests Th e plain radiograph s m ay be difficult to in terpret in two dim en sion s. A th ree-dim en sion al study, such as a CT scan , will better define th e size and location of the osteophytes an d m ay be useful for preoperative plan n in g. Differential Diagnosis OA of th e elbow is typically diagn osed by plain radiograph s. It m ust be distin guish ed from oth er form s of elbow DJD. In th e presen ce of n orm al radiograph s, soft tissue contracture m ay cause sim ilar pain and loss of m otion . Treatment In itial treatm en t is con servative, con sistin g of an tiin flam m atory m edication s an d activity m odification . Later stages m ay respond to arthroscopic debridem ent, capsular release, an d rem oval of osteophytes. Care m ust be taken n ot to destabilize th e elbow join t with overaggressive

Pathophysiology and Classification Th e articular cartilage of th e elbow, particularly of th e distal h um erus, is am on g th e th in n est in th e body. Failure to an atom ically restore th e joint surface can lead to uneven wear of th e rem ain in g cartilage, followed by rapid degen eration of the joint. However, even after an an atom ic reduction, there m ay be cartilage loss. A direct impact to the joint surface has been sh own to cause apoptosis of th e chondrocytes with subsequent loss of articular cartilage. Patien ts are typically classified on a descriptive basis. The original in jury pattern , presen ce or absen ce of h ardware, an d degree of soft tissue or bony con tracture are n oted. Presentation Wh ile posttraum atic arth ritis will occur in m any differen t form s, th e com m on thread is the history of traum a. Patients will usually complain of pain and loss of m otion. Th ey often will h ave h ad m ultiple prior procedures. Any operative reports, radiograph s, or office n otes are h elpful. It is importan t to determ in e wh eth er th e origin al in jury was open or closed and whether any wound complications occurred followin g surgery. Physical Examination A thorough inspection of the skin is th e initial step in the physical exam in ation . Many patien ts will exh ibit com prom ise of th e soft tissue envelope. Any open wounds or draining sinuses should be noted. Prior surgical incisions are exam in ed for eviden ce of in fection an d for future surgical plan n in g. Ran ge of m otion is recorded alon g with th e presen ce of crepitus or grin din g. Any deform ity or in stability is also noted. Radiographic Findings Th e radiograph ic fin din gs of posttraum atic arth ritis will sh ow a sim ilar loss of joint space as seen in other form s of DJD. Usually, h owever, th ere will also be h ardware presen t, wh ich can obscure th e im ages. Th e h ardware sh ould be evaluated for loosen in g, breakage, or pen etration in to th e join t. Varyin g degrees of bon e loss an d eviden ce of un un ited segm en ts m ay also be presen t. HO is a com m on fin din g after elbow traum a, an d its presen ce an d location sh ould be n oted.


Special Tests A m ajor con cern in th e posttraum atic elbow is th e possibility of in fection. Laboratory workup including WBC, ESR, an d CRP will offer evidence for or against the presence of infection. Joint aspiration can also aid in the diagn osis. CT scan is helpful in determ in in g such factors as the location of HO, th e presen ce of n on un ited segm en ts, an d areas of bon e loss. Differential Diagnosis Th e m ain difficulty is th e diagn osis of posttraum atic arth ritis is the evaluation of the joint surface. In the presence of traum a, m any oth er factors besides cartilage loss can cause symptom s. HO, soft tissue con tracture, in fection, and nonunion m ay all contribute to painful loss of m otion in the elbow. Treated separately, these con ditions m ay relieve a great deal of th e patien t’s complain ts, with out requirin g interven tion at the joint surface. Treatment Th e treatm en t of posttraum atic arth ritis varies on th e basis of th e presenting com plaints an d m ust be tailored to each in dividual. Con servative m easures in clude an tiinflam m atory m edications and activity restriction. Any suspicion for infection should be diagnosed an d treated accordingly. Operative treatm ent is chosen on th e basis of the patient’s needs. Hardware rem oval, contracture release, an d repair of nonunited segm en ts can relieve m any symptom s. Addressin g articular surface degen eration is m ore ch allenging. Arthrodesis of the elbow is less successful than it is in other joints, leaving patien ts very disabled. TEA requires lifelon g activity restriction an d con version to a lowdem an d lifestyle. Th is is often n ot possible for a youn g, active patient who m ust use the elbow for work. Interposition arthroplasty, using fascial tissue, has been used with success but is a tech n ically dem an ding procedure with results th at m ay be unpredictable.

with 6 weeks bein g an arbitrary cutoff for an acute epicondylitis. Presentation Because th e condition is a degen erative process, patien ts typically presen t durin g th eir m iddle age. Th ey usually h ave a h istory of overuse or repetitive traum a, but som e patien ts will describe an acute in citin g even t. Patients with lateral epicon dylitis presen t with lateral elbow pain , wh ich is exacerbated by activities in volvin g resisted wrist exten sion . Tigh t grasping will also cause pain, as wrist extension is compon en t of a power grip. Patien ts with m edial epicon dylitis complain of m edial elbow pain with activities involvin g resisted wrist flexion an d pron ation . Physical Examination When m edial or lateral epicon dylitis is suspected by history, a complete elbow exam in ation m ust still be perform ed such that concom itant pathology is not m issed. Th is should in clude a com plete ran ge of m otion and stability exam in ation . A careful n eurovascular exam in ation is also importan t to rule out compressive n europath ies, such as radial or cubital tun n el syn drom e. For lateral epicon dylitis, palpation over th e lateral epicon dyle will reproduce the patient’s symptom s. Pain with resisted wrist extension (Fig. 14.36), kn own as Mill test, or pain with passive wrist flexion and elbow extension are two specific m aneuvers that will cause pain in lateral epicondylitis. The radiocapitellar joint and radial tunnel sh ould be palpated for ten dern ess. Pain with resisted supin ation is m ore likely secon dary to a partial biceps rupture or radial tun n el syndrom e. A pivot sh ift is perform ed to iden tify PLRI. For m edial epicon dylitis, the m edial epicon dyle is palpated for ten dern ess. Pain with resisted flexion an d pron ation will reproduce th e symptom s. Th e uln ar n erve is exam in ed for subluxation , ten dern ess, or a Tin el sign to rule out ulnar nerve in volvem en t. Valgus stress testing will

Lateral and Medial Epicondylitis Lateral and m edial epicondylitis, also known as tennis and golfer’s elbow, respectively, are am on g the m ost com m on con ditions causing elbow pain . Simple activities of daily living are painful to impossible, leading to a great deal of disability with lost tim e from work an d recreation .

Pathophysiology and Classification Th e term epicondylitis is actually a m isnom er. The suffix itis implies that an inflam m atory process is taking place. Histologic analysis, h owever, has revealed that th e process is an age-related degeneration of th e tendon fibers. In tennis elbow, the fibers of th e ECRB are m ost often involved, wh ereas th e PT an d FCR are in volved in golfer’s elbow. Th e con ditions are broadly classified into m edial or lateral epicon dylitis on the basis of location of the symptom s. They are further subdivided into acute and chronic processes,

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Figure 14.36 Mill test for lateral epicondylitis.

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cause pain if the path ology is secondary to MUCL insufficiency. Radiographic Findings Im agin g studies are rarely h elpful in m edial an d lateral epicondylitis as th e diagnosis is gen erally a clinical one. Plain radiographs m ay dem on strate calcification s aroun d the involved epicon dyle, but th is h as n o kn own progn ostic or treatm en t value. Special Studies Advanced im aging does not typically add any inform ation as th e diagn osis is based on clin ical fin din gs. EMG studies are obtain ed if suspicion for uln ar or PIN in volvem en t exists. Un fortun ately, EMG studies are often tim es n orm al in these conditions. Differential Diagnosis Th e differen tial diagn osis for lateral epicon dylitis in cludes radial tunnel syndrom e, radiocapitellar DJD, PLRI, and intraarticular plical folds. Th e differen tial diagn osis on th e m edial side in cludes cubital tun n el syn drom e an d MUCL in sufficien cy. Again , it m ust be rem em bered th at m ore th an on e con dition m ay occur sim ultan eously. Treatment In itial treatm en t is con servative an d aim ed at relievin g symptom s. A period of rest from 2 to 6 weeks is advocated, particularly in acute cases, with avoidan ce of aggravatin g activities. Braces are design ed to tran sfer th e force from th e origin of th e ten don to th e m uscle belly. An in jection of corticosteroid m ay help to relieve symptom s. Therapy m ay offer an addition al resource in th e treatm en t arm am en tarium , with tech n iques such as cross-friction m assage an d US. The vast m ajority of patients will respon d to a nonoperative program . Those patien ts who fail 6 m on ths of conservative m an agem en t, h owever, are can didates for surgical treatm en t. For lateral epicon dylitis, th e procedure can be perform ed eith er open or arth roscopically. In th e open approach , th e fibers of th e ECRB are iden tified, th e degen erative tissue is excised, an d th e footprin t of th e ECRB is drilled or decorticated. Th e LUCL m ust be avoided to preven t iatrogen ic PLRI. Th e arth roscopic approach offers th e advan tage of rem oval of any con com itan t in traarticular plicae an d a faster return to work; h owever, th ere is a greater risk of complication s, especially n erve in jury. Sim ilar to lateral epicon dylitis, th e approach to m edial epicon dylitis in volves excision of th e degen erated portion of th e flexor–pron ator ten don . Care m ust be taken n ot to in jure th e MUCL.

Olecranon Bursitis Th e olecran on bursa lies on th e dorsal aspect of th e proxim al uln a as a protective tissue between th e skin an d bon e. It is a frequen t area of in flam m ation an d a com m on cause of elbow pain .

Pathophysiology and Classification Th e bursa is a poten tial space th at n orm ally h as on ly a th in layer of fluid but m ay becom e significantly larger when inflam ed. Olecranon bursitis can begin from overuse or a direct traum a. Septic bursitis occurs when the bursa is seeded or in oculated with bacteria. Presentation Patients will present with pain along the posterior elbow an d will report varying degrees of swelling. Often, they will n ot recall a specific traum a but will report a h istory of pressure on th e area, such as restin g it on a car door wh ile drivin g. Septic bursitis m ust be con sidered in patien ts wh o presen t with fevers, eryth em a, or h istory of pen etrating traum a to the area. Physical Examination Som e cases of olecran on bursitis are obvious an d presen t with a m assive fluid-filled bursa. O th er cases are less dram atic with ten derness to palpation an d only m ild or no swellin g. Chron ic cases m ay h ave tender, palpable nodules with in th e bursa. In spection for open woun ds, purulen t drain age, eryth em a, or warm th sh ould raise th e suspicion for a septic process. Radiographic Findings Plain radiograph s m ay sh ow th e fluid with in th e bursa. Many patients will h ave an olecranon spur. Special Studies Advanced im aging is rarely n ecessary for the diagn osis of olecran on bursitis. US m ay con firm th e presen ce of fluid with in th e bursa. MRI can also con firm th e presen ce of fluid and help identify ch aracteristics of th e fluid, such as the presence of loculations. MRI can also yield inform ation regardin g oth er tissues, such as th e in tegrity of th e triceps ten don , if it is in question . Laboratory values are obtain ed if infection is a possibility. Aspiration of the bursa is sent for culture in cases of septic bursitis if iden tification of an organ ism is n ecessary. Differential Diagnosis A partial or com plete triceps ten don rupture m ust be con sidered in a patien t with posterior elbow pain. Pain with resisted elbow exten sion will h elp distin guish a triceps tear from olecran on bursitis. Treatment Treatm ent of the in flam ed bursa begins conservatively with un loadin g of th e area. Avoidin g aggravatin g activities or using elbow padding is effective in m ost cases. Aspiration of the bursa is controversial in that it relieves m uch of the swellin g, but con cerns exist regarding recurrence and form ation of a draining sinus. In chronic cases that fail to respon d to n on operative treatm en t, bursal excision m ay be con sidered; however, recurren ce and wound failure rem ain


com m on complications. Septic bursitis can be empirically treated with antibiotics in a stable patient. Failure to respond to appropriate antibiotics, however, necessitates irrigation an d debridem en t with bursal excision .

Cubital Tunnel Syndrome Ulnar nerve compression at the elbow, or cubital tun nel syndrom e, is the second m ost com m on compressive neuropathy after carpal tunnel syndrom e. Th ere are m any causes of cubital tunnel syn drom e and m any other disease processes with sim ilar sym ptom s, m akin g diagn osis ch allenging.

Pathophysiology and Classification As the ulnar nerve crosses the elbow, it passes ben eath the m edial epicondyle of the hum erus. When the elbow is flexed and pronated, m axim um traction is placed across the nerve, with som e patients experiencin g n erve subluxation. Repetitive use of the elbow in these position s is the cause of symptom s in m ost patients. Other causes include direct traum a, delayed traum a in th e form of tardy uln ar nerve palsy, and space-occupyin g lesion s, such as gouty toph i or gan glion cysts. Presentation Patients will present with vague pain along the m edial elbow. Classically, th ey will h ave paresth esias an d dysesthesias alon g th e ulnar forearm into the rin g and sm all finger. Patien ts will often com plain of weakn ess of th e h an d, as th e intrinsic m uscles are inn ervated by th e ulnar nerve. Sym ptom s com m on ly occur with th e elbow in th e flexed position . Physical Examination Th e physical exam in ation is crucial in th e evaluation of cubital tun nel syndrom e, as m any other conditions have sim ilar sym ptom s. Th e uln ar nerve is m ade up of the lower roots of th e brach ial plexus, specifically C8 an d T1. Th e roots becom e th e m edial cord of th e plexus an d ultim ately the ulnar n erve. Compression anywhere along th e pathway can cause the symptom s of cubital tunnel syn drom e. Th e exam in ation begin s with testin g for cervical n erve root compression by evaluating the range of m otion an d perform ing a Spurling m aneuver. The axilla is then exam ined for any palpable m asses, and an Adson or Wright m aneuver is perform ed for the presence of thoracic outlet syn drom e. Th e elbow exam in ation begin s with palpation of th e m edial elbow. Ten dern ess, n erve subluxation , or Tin el sign are all noted. Reproduction of symptom s with the elbow held in a flexed position helps confirm th e diagnosis. Th e carrying an gle should also be evaluated for the possibility of tardy uln ar n erve palsy from posttraum atic deform ity. A complete elbow exam in ation for range of m otion and stability is perform ed. Th e wrist is exam in ed for presen ce of nerve compression at Guyon can al. A Tinel sign is elicited an d the hook of the ham ate exam ined for tenderness or

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a pulsatile m ass. Weakn ess m ay exist when testing in trinsic m uscles. Patients m ay compen sate for the loss of finger abduction with fin ger hyperexten sion . Th e first dorsal in terosseous m uscle is easily palpated in th e first webspace, with attempted in dex finger abduction. Decreased sensation m ay be presen t alon g th e little fin ger an d uln ar side of the ring finger. Radiographic Findings Plain radiograph s of th e elbow are obtain ed an d are usually n orm al. They m ay dem on strate posttraum atic deform ity or callus with in the area of th e cubital tunnel. An epicon dylar view m ay be added to obtain a clear im age of th e groove an d evaluate for th e presen ce of osteophytes or oth er lesion s. Radiograph s of oth er areas of th e body, such as th e cervical spin e, chest, an d wrist are taken, depending on clin ical suspicion followin g th e physical exam ination. Special Tests Advanced im agin g is rarely helpful in th e diagnosis of cubital tun n el syn drom e. MRI can be obtain ed if con cern exists for a space-occupyin g lesion . Electrodiagn ostic studies, such as EMG an d NCV, help to confirm the diagnosis and localize th e compression in equivocal situation s. False n egatives do occur an d treatm en t for cubital tun n el syn drom e sh ould proceed accordin gly if the clinical exam ination is clear, despite a norm al EMG/NCV. Differential Diagnosis As stated earlier, the differential diagnosis is extensive. Many con dition s h ave overlappin g symptom s, an d differen t con dition s m ay occur sim ultan eously. Th e differen tial diagn osis begin s with cervical n erve root com pression . Travelin g down th e arm , brach ial plexus com pression from thoracic outlet syndrom e or a Pancoast tum or is considered. At th e elbow, MUCL in sufficien cy an d m edial epicondylitis are evaluated. At the wrist, ulnar nerve compression at Guyon canal, aroun d the hook of the ham ate, or secon dary to ulnar artery aneurysm is also considered. Last, system ic abnorm alities that m ay produce peripheral neuropathy, such as vitam in deficien cy, h eavy m etal in toxication , an d alcoh olism , are all in cluded in th e differen tial diagn osis. Treatment In itial treatm ent is con servative. Splin tin g is effective in reducin g th e am oun t of elbow flexion , particularly at n igh t. Nigh ttim e 45-degree splin ts relieve a sign ifican t portion of in volun tary compression . Daytim e flexion is avoided, an d full-tim e splinting m ay be considered in severe cases. Antiin flam m atory m edication s an d th erapy m odalities m ay also be added. In refractory cases, surgical treatm en t is in dicated. Th ere is con troversy in th e various treatm en t m easures available. In all cases, h owever, all areas of com pression or poten tial compression m ust be addressed. Surgical tech n iques vary from simple decompression to n erve

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Figure 14.37 Ulnar nerve transposition. (Reproduced with permission from Morrey BF. Master

Techniques in Orthopaedic Surgery: The Elbow. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2002.)

tran sposition (Fig. 14.37). If tran sposition is perform ed, m ultiple m eth ods h ave been described placin g th e n erve in a subcutan eous or a subm uscular position . Head-to-h ead trials dem on stratin g a sign ifican t ben efit of on e treatm en t compared with another are lacking. The possible complications from surgical treatm ent are nerve dysfunction or dam age, in com plete release, an d dam age to th e m edial an tebrach ial cutan eous n erve.

wh ich is disability, often lim itin g th e patien t’s ability to perform daily activities. Advan ces in th e un derstan din g of elbow biom ech an ics an d path ology h ave led to im proved diagn ostic an d treatm en t option s for patien ts with elbow disorders. Furth er research will con tin ue to advan ce our knowledge and expand our ability treat th ese devastating con dition s.

RECOMMENDED READINGS

CONCLUSION For n orm al elbow fun ction , a delicate in terplay of bon es, ligam en ts, an d m uscles m ust exist. Traum atic an d atraum atic disorders disrupt th is delicate in terplay in m ultiple differen t ways. Th ey all lead to a com m on en dpoin t,

Cheung EV, Steinm ann SP. Surgical approaches to th e elbow. J Am Acad Orthop Surg. 2009;17:325 –333. Cheung EV, Adam s R, Morrey BF. Prim ary osteoarthritis of the elbow: current treatm ent options. J Am Acad Orthop Surg. 2008;16:77 –87. Mathew PK, Athwal GS, King GJW. Terrible triad injury of th e elbow: current concepts. J Am Acad Orthop Surg. 2009;17:137 –151. Sarm ien to A, Waddell JP, Latta LL. Diaphyseal h um eral fractures: treatm ent options. J Bone Joint Surg Am. 2001;83:1566 –1579.

15

Hand and Wrist Nick Pappas

Jon as L. Matzon

Pedro K. Beredjik lian

HAND AND WRIST SURGERY Our hands serve as our gateway to the outside world. They en able us to touch , eat, com m un icate, an d perform coun tless other tasks of daily living. With out them , we are lim ited in our ability to interact in society. Perh aps one can only truly appreciate their importance wh en an injury or disease process lim its th eir use. In th is ch apter, th e diagn osis an d treatm ent of several basic hand injuries and conditions will be explored.

ANATOMY Anatomy of the h and is m ore intricate than perhaps any oth er area of th e m usculoskeletal system . Kn owin g th e an atomy is fundam ental to un derstanding the basic han d function and to diagnosing dysfun ction when evaluating a patien t with a h an d in jury in th e clin ic or em ergen cy departm en t settin g.

BONE AND LIGAMENT Carpus Th e carpus is composed of eigh t bon es th at are organ ized in two rows of four. The proxim al row in cludes the scaphoid (navicular), lunate, triquetrum , an d pisiform (Fig. 15.1). Each of th ese bon es h as ch aracteristic features th at assist in its radiograph ic identification. The scaph oid is boatsh aped an d has a prom in ent tubercle distally. Th e lun ate is m oon-shaped an d has been classified into two types. A type I lun ate (30% of patien ts) does not articulate with the ham ate, whereas a type II lunate (70% of patients) has a m edial facet th at articulates with th e proxim al h am ate an d increases the risk of potential ham ate arth rosis. The triquetrum is pyram idal in shape. Last, the pisiform is a

sm all roun d sesam oid bone th at sits on the volar surface of th e triquetrum an d is con tain ed with in th e flexor carpi uln aris (FCU) ten don . Collectively, th e proxim al row is referred to as the intercalary segm ent because it conn ects the forearm to the distal carpal row and is not controlled by any m usculoten din ous structures. Th e distal carpal row is m ade up by th e trapezium , trapezoid, capitate, an d h am ate. Th e trapezium is four-sided an d sits at th e base of th e thum b m etacarpal (TM). The trapezoid is wedge-sh aped an d is th e sm allest bon e of th e distal row. Th e capitate is th e largest carpal bon e an d h as a roun ded portion th at articulates with th e scaph oid an d lun ate. Th e h am ate is also wedge-sh aped an d h as a h ook-like process on its volar surface kn own as th e hamulus or hook of the hamate. Th e carpal bon es are stabilized by n um erous ligam en ts, wh ich can be divided into in trinsic and extrinsic. In the proxim al row, th e two m ost importan t in trin sic ligam en ts are th e scaph olun ate an d th e lun otriquetral. Th ey stabilize their respective bony structures but also allow for sm all am oun ts of rotation al m otion between th em . Th e m ost importan t of th e extrin sic ligam en ts of th e proxim al row are th e volar ligam en ts an d in clude th e radio – scaph oid –capitate, lon g radiolunate, an d short radiolunate (Fig. 15.2A). Th ese ligam ents are thickenin gs of th e join t capsule and serve to anchor the proxim al row to th e distal radius and ulna. While these ligam ents stabilize the radiocarpal joint radially, the ulnocarpal ligam ents (includin g the uln olunate, ulnotriquetral, and ulnocapitate) provide support uln arly. Th e m ost importan t dorsal ligam en ts are th e dorsal tran sverse in tercarpal, wh ich run s from th e scaph oid to the triquetrum , and the dorsal radiocarpal ligam en t, which connects the radius to the triquetrum . These two ligam ents form a “V’’ with the apex of th e “V’’ directed ulnarly (Fig. 15.2B). Th e radiocarpal join t is composed of th e distal radius an d proxim al carpal row. Th e distal radius h as a separate

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m otion (in addition to the rotational m otion) of the ulna on th e radius durin g pron ation an d supin ation . Th e uln ar pole an d DRUJ are surroun ded by a structure called the triangular fibrocartilage complex (TFCC) (Fig. 15.4). Th e TFCC serves to stabilize th e DRUJ an d absorb force directed from the carpus to the uln ar pole. It is com posed of th e uln otriquetral an d uln olun ate ligam en ts, th e volar and dorsal radioulnar ligam ents, th e ulnar collateral ligam en t, th e subsh eath of th e exten sor carpi uln aris (ECU), a m eniscus hom olog, and an articular disk (trian gular fibrocartilage).

METACARPAL AND PHALANGEAL STRUCTURES

Figure 15.1 Bony anatomy of the hand and wrist. (Reprinted

with permission from Doyle JR, Botte MJ. Surgical Anatomy of the Hand and Upper Extremity. Philadelphia, PA: Lippincott Williams & Wilkins, 2003.)

facet for articulation with both th e scaph oid an d lun ate. Th e distal radius is tilted volarly at an an gle of approxim ately 11 degrees (Fig. 15.3). Its an gle of in clin ation is rough ly 22 degrees, wh ereas its h eigh t is approxim ately 11 m m relative to its m ost uln ar surface. The m n em onic “11 –22 –11’’ can be useful for rem em bering these relation sh ips, wh ich are im portan t in evaluatin g distal radius fractures. The distal radioulnar joint (DRUJ) is th e last articulation in th e radiocarpal region th at m erits atten tion . Th e distal uln a is divided in to two separate articular surfaces: th e ulnar seat, which abuts the sigm oid n otch, and the ulnar pole, which faces the carpus. The uln ar seat is surrounded by a 105-degree arc of articular cartilage, wh ich correspon ds to a 10 m m radius of curvature. Th is radius of curvature of the ulnar seat is substantially less than th at of the sigm oid notch , which is 15 m m an d correspon ds to an arc of curvature of approxim ately 60 degrees. Therefore, the DRUJ is n ot con gruen t. Th is in con gruen cy en ables tran slation al

Th e m etacarpus is th e skeletal region of th e h an d, bordered by th e distal carpal row proxim ally an d th e ph alanges distally. It consists of five elon gated bon es with a h ead, neck, body, an d base area. Th e TM differs sligh tly from th e others in that its epiphysis is located proxim ally instead of distally, and its base is saddle-shaped, which increases overall m obility. All th e MC heads are cam -shaped, m eaning that their diam eter from palm ar to dorsal is larger than from the distal head to neck junction . Th e m etacarpoph alan geal (MCP) join ts are stabilized m edially an d laterally by radial an d uln ar collateral ligam en ts. Th ese ligam ents start dorsally on the MC h ead and attach volarly on th e proxim al ph alan x. Because of th e cam sh ape of the MC heads, th e collateral ligam ents are taut in flexion and lax in extension (Fig. 15.5). In addition, th e volar surface of th e MCP join t contain s fibrous thickenings of the joint capsule, collectively referred to as volar plates, wh ich add stability to th e join t an d serve as restrain ts to hyperexten sion . Th e ph alan ges articulate directly with th e MC h eads. Each digit is com posed of th ree ph alan ges (proxim al, m iddle, an d distal) with th e exception of th e th um b, wh ich h as only a proxim al an d distal ph alan x. Th e ph alan ges decrease in size as one m oves from proxim al to distal. Th eir h eads are bicon dylar in sh ape, un like th ose of th e aforem en tioned MCs. They are stabilized laterally and m edially by collateral ligam ents, which sh are the sam e orientation as those in the MCs.

MUSCLES AND TENDONS Extrinsic Flexors Th e flexors of th e h an d an d wrist in clude th e flexor carpi radialis (FCR), palm aris lon gus (PL), FCU, flexor pollicis longus (FPL), flexor digitorum superficialis or sublim is (FDS), and flexor digitorum profundus (FDP). The FCR origin ates on th e m edial epicon dyle of th e h um erus an d

Chapter 15: Hand and Wrist

A

585

B Figure 15.2 (A) Volar radiocarpal ligaments. (B) Dorsal radiocarpal ligaments. (Reprinted with permission from Doyle JR and Botte MJ. Surgical Anatomy of the Hand and Upper Extremity. Philadelphia: Lippincott Williams & Wilkins, 2003.)

inserts at the base of the second and third MCs. It helps to flex and radial deviate the wrist. O f note, it runs outside the carpal tunnel at th e wrist, just superficial and radial to th e m edian nerve. The PL originates on the m edial epicondyle an d inserts at the palm ar aponeurosis. It is a weak wrist flexor and is absen t in approxim ately 10% of patients. One can readily identify the PLon his or her own wrist by touching the thum b to th e sm all finger and flexin g the wrist. If presen t, th e ten don can be visualized. Th e FCU origin ates from th e m edial epicondyle an d posterior ulna to insert on the h ook of th e ham ate and fifth MC base. It is the m ost powerful wrist flexor an d h elps to flex an d uln ar deviate

the wrist. Of note, its m uscle belly extends farther distally as compared with oth er wrist flexors. Regardin g the fin ger flexors, the FPL origin ates on the an terior aspect of th e radius an d th e coron oid process to in sert on th e distal ph alan x of th e th um b. It passes th rough the carpal tunn el and lies just radial to the m edian nerve. It assists in th um b flexion at th e in terph alan geal joint. Th e FDS origin ates on th e m edial epicon dyle, coron oid process, and anteroproxim al radius and passes through the carpal tunnel to insert on the m iddle phalanges of th e index th rough sm all fin gers. It assists in flexion of th e proxim al in terph alan geal (PIP) join ts of th ose digits. Of n ote,

Figure 15.3 The normal volar tilt of the distal radius av-

erages 11 degrees. (Reprinted with permission from Harris JH, Harris WH. Radiology of Emergency Medicine. 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2000.)

A

B

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Figure 15.4 Components of the distal radioulnar joint.

ECU, extensor carpi ulnaris. (Reprinted with permission from Doyle JR, Botte MJ. Surgical Anatomy of the Hand and Upper Extremity. Philadelphia, PA: Lippincott Williams & Wilkins, 2003.)

the tendons to the lon g and ring fingers are m ore superficial than those to the index and sm all at the level of the carpal tunn el. The FDP originates off the anterior ulna and in terosseous m em bran e an d run s th rough th e carpal tun nel on its way to in serting on the distal ph alan ges of th e in dex th rough sm all fin ger. It allows flexion of th e distal in -

terph alan geal (DIP) join ts of all but th e th um b (Fig. 15.6). Th e FDS an d FDP ten don s sh are a un ique relation sh ip at th e level of th e MP join ts. In th is region , wh ich is kn own as Camper chiasma, th e FDS splits in to a radial an d uln ar slip and inserts dorsal to the FDP on the proxim al one-third of th e m iddle ph alan x. Th e FDP ten don run s th rough th is

A B

MC

PH

MC

PH Figure 15.5 The cam shape of the metacarpal heads causes the collateral ligaments to be more taut in flexion than extension. MC, metacarpal; PH phalanx. (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)


Bra chia lis Bice ps bra chii Bra chia lis Mus culocuta ne ous ne rve

Bra chia l a rte ry Me dia n ne rve Me dia l e picondyle of hume rus

Bicipita l a pone uros is

P rona tor te re s

Ra dia l a rte ry

Fle xor ca rpi ra dia lis

Bra chiora dia lis Ra dia l a rte ry S upe rficia l bra nch of ra dia l ne rve Fle xor pollicis longus P rona tor qua dra tus Abductor pollicis longus S upe rficia l pa lma r bra nch

P a lma ris longus Fle xor ca rpi ulna ris Fle xor digitorum s upe rficia lis Me dia n ne rve Ulna r a rte ry a nd ne rve P is iform P a lma ris bre vis P a lma r a pone uros is P a lma r digita l a rte rie s a nd ne rve s S upe rficia l tra ns ve rs e me ta ca rpa l liga me nt

(A) An te rio r vie w

587

split an d in serts on th e distal phalanx, as m entioned previously. Th e flexor ten don s en ter fibro-osseous tun n els kn own as flexor sheathsat th e level of th e MCP join ts. Th ese sh eath s are lin ed with synovium and enable the flexor tendons to glide sm oothly as the finger flexes. Surroun ding these sheaths are bandlike thickenings known as the annular and cruciate pulleys. Th ere are five an n ular pulleys an d th ree cruciate. Th e A-1 pulley is attach ed to a volar plate at th e level of th e MP joint and is often responsible for digit triggering. The A-2 an d A-4 pulleys are located at th e base of th e proxim al an d m iddle ph alanx, respectively, and are the m ost importan t m ech an ically due in part to th eir direct attach m en t to bon e. Th ey are essen tial in preven tin g bowstrin gin g of th e ten don s. Th e A-3 an d A-5 pulleys are foun d at th e level of the PIP and DIP joints, respectively, and also attach to volar plates (Fig. 15.7). Th e th ree cruciate pulleys—C-1, C-2, an d C-3—run between the an nular pullies, providing an additional teth er of th e flexor sheath to the phalangeal bones. Proxim al to th e A-1 pulley, th e flexor ten don s receive th eir n utrition from th e surroun din g paratenon. Distal to th e A-1 pulley, th e flexor ten don s receive th eir blood supply dorsally via vinculae, which are folds of m esotenon that run from the tendons to the bone. Th e pulley system of th e th um b is sligh tly m odified due in part to its having on ly one flexor tendon, the FPL. In addition to the A-1 pulley at the MCP join t, there is an oblique pulley th at lies over th e proxim al ph alan x. Last, an A-2 pulley can be foun d over th e IP join t. Both th e A-1 and A-2 pulleys attach to volar plates as opposed to th e oblique pulley, wh ich attach es to bon e.

Extrinsic Extensors Fle xor pollicis longus

P rona tor qua dra tus

P rona tor qua dra tus

Dors a l (cuta ne ous ) bra nch

P a lma r ca rpa l bra nch

Dors a l ca rpa l bra nch

P a lma r ra dioca rpa l bra nch S upe rficia l pa lma r bra nch (B)

Fle xor digitorum profundus P e rs is ting me dia n a rte ry Me dia n ne rve

Th e exten sors of th e wrist an d h an d in clude th e exten sor carpi radialis lon gus (ECRL), exten sor carpi radialis brevis (ECRB), ECU, extensor digitorum com m unis (EDC), exten sor in dicis proprius (EIP), an d exten sor digiti m in im i (EDM) (Fig. 15.8). Th e extensor tendons run in six separate dorsal compartm en ts, wh ich are form ed by th e exten sor retin aculum . Th e con ten ts of th e in dividual compartm en ts are listed in Table 15.1. Th e ECRL origin ates on th e lateral aspect of th e supracon dylar h um erus an d in serts at th e base of th e secon d MC.

P a lma ris longus Fle xor ca rpi ra dia lis

TABLE 15.1

EXTENSOR COMPARTMENTS OF THE WRIST Figure 15.6 Two views of the volar forearm, showing the relationships of the volar forearm flexors to one another and the surrounding neurovascular structures. (Reprinted with permission from Moore KL, Dalley AF. Clinically Oriented Anatomy. 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 1999.)

1. 2. 3. 4. 5. 6.

Abductor pollicis longus, extensor pollicis brevis Extensor carpi radialis longus, extensor carpi radialis brevis Extensor pollicis longus Extensor digitorum communis, extensor indicis proprius Extensor digiti minimi Extensor carpi ulnaris

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Collateral ligament Distal interphalangeal joint

Accessory ligament Collateral ligament Metacarpal phalangeal joint Proximal interphalangeal joint

Rexor digitorum profundus C3 pulley

Rexor digitorum superficialis

A2 pulley

A4 pulley C2 pulley

A3 pulley

C1 pulley

A1 pulley

Figure 15.7 The pulley system of the finger. (Adapted with permission from Hoppenfeld S, deBoer P. Surgical Exposures in Orthopaedics: The Anatomic Approach. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2003.)

It en ters th e wrist as part of th e secon d dorsal compartm en t alon g with th e ECRB. It fun ction s to exten d th e wrist. Th e ECRB originates on the lateral epicondyle of the hum erus an d in serts m ore cen trally th an th e ECRL at th e base of th e third MC. In a m anner sim ilar to the ECRL, it functions to exten d th e wrist. Th e ECRB is often implicated in lateral epicondylitis (i.e., ten n is elbow). Th e ECU origin ates on th e lateral epicon dyle an d in serts at th e base of th e fifth MC. It assists in exten din g th e h an d in an uln ar direction . The extensor m ech an ism of the fingers is m ore complex than that of the wrist. The EDC originates from the lateral epicon dyle to in sert on th e sagittal bands of th e exten sor hood of the index through sm all fin gers. The EIP and EDM also in sert on th e sagittal ban ds but on ly on th e in dex an d sm all fingers, respectively. These ten don s lay ulnar to th eir respective com m on exten sor ten don on th e dorsum of th e hand. The EIP originates from the posterior aspect of the uln a wh ile th e EDM origin ates from th e lateral epicon dyle. The sagittal bands are localized to the MP joint and h elp to centralize th e exten sor tendons over this region, which is collectively known as the extensor hood. Distal to th e sagittal ban ds at th e level of proxim al ph alan x, th e ten don s of th e lum bricals an d in terossei in sert an d becom e part of th e lateral bands. The exten sor tendon trifurcates just distal to the MCP join t, form ing a central slip, which inserts on the m iddle ph alan x an d two oth er slips, wh ich join th e lateral ban ds to in sert on th e distal ph alan x. Th e oblique retinacular ligament (ligam en t of Lan dsm eer) origin ates volarly on th e flexor sheath an d attaches dorsally on th e lateral term inal exten sor ten don . It lin ks m otion of th e DIP an d PIP join ts. The transverse retinacular ligament origin ates on th e flexor sh eath at th e PIP and inserts on th e lateral bands. This ligam en t stabilizes th e lateral ban ds, preven tin g excessive dorsal m igration durin g PIP exten sion an d volar m igration durin g flexion (Fig. 15.9). Th e exten sors of th e th um b in clude th e exten sor pollicis lon gus (EPL), exten sor pollicis brevis (EPB), an d th e abductor pollicis lon gus (APL) (Fig. 15.10). Th e EPL origin ates on th e posterior uln a an d in serts at th e base of th e

distal ph alan x of th e th um b. If serves to exten d th e th um b IP join t. Th e EPL m akes a 45-degree turn at Lister tubercle on th e dorsum of th e radius just after passin g th rough th e third dorsal extensor compartm ent of the wrist. It is th e m ost com m on ten don rupture associated with a distal radius fracture. Th e EPBorigin ates on th e posterior radius an d in serts at the base of the proxim al phalanx of the thum b. It exten ds th e th um b at th e carpom etacarpal (CMC) join t. Th e APL origin ates on th e posterior aspect of th e radius an d uln a, an d togeth er with th e EPB, courses th rough th e first dorsal exten sor com partm en t before in sertin g at th e base of th e first MC. It abducts an d exten ds th e th um b at the CMC joint.

INTRINSIC HAND MUSCLES Th e in trin sic m uscles in th e h an d are term ed intrinsic because they both originate and insert on the hand (Fig. 15.11). They can be divided into four groups: lum bricals, interossei, thenar, and hypothenar. The lum bricals origin ate on th e FDP ten don s an d in sert on th e radial aspect of the lateral bands, which are part of the exten sor hood. Th e m uscle bellies of th e lum bricals of th e in dex, an d lon g fin ger are unipennate, whereas those of th e ring and sm all fin gers are bipennate. They fun ction to exten d th e PIP join ts an d flex the MCP joints. Lum bricals are un ique in that they insert on th eir own an tagonist (i.e., the term in ation of the exten sor ten don s, wh ich exten d th e MCP join ts). Th e two m ost radial lum bricals are in nervated by the m edian n erve, wh ereas th e two uln ar lum bricals are in n ervated by th e uln ar n erve. Th ere are seven in terosseus m uscles: th ree volar an d four dorsal. Th e volar in terossei origin ate on th e uln ar side of the index finger MC and the radial side of the ring an d sm all finger MC to insert at the base of the proxim al phalanx an d extensor hood. They are unipennate and assist in digit adduction . Th e dorsal in terossei origin ate from th e thum b to sm all finger MC to insert in th e sam e location


589

Bra chiora dia lis Ancone us a nd its ne rve Exte ns or ca rpi ra dia lis longus

La te ra l mus cle s

Exte ns or ca rpi ra dia lis bre vis

Exte ns or digitorum Exte ns or digiti minimi

Exte ns or ca rpi ulna ris

Abductor pollicis longus

Exte ns or indicis

Exte ns or pollicis bre vis

Outcropping mus cle s of the thumb

Exte ns or pollicis longus Exte ns or re tina culum

Dors a l ca rpa l bra nch of ulna r a rte ry Dors a l ca rpa l a rch P e rfora ting a rte rie s Dors a l me ta ca rpa l a rte rie s

Common fibrous s he a th of a bductor pollicis longus a nd e xte ns or pollicis bre vis Ra dia l a rte ry in the a na tomica l s nuff box Dors a l ca rpa l bra nch of ra dia l a rte ry Dors a le s pollicis a rte rie s Dors a lis indicis a rte ry

Dors a l digita l a rte rie s

Figure 15.8 Illustration demonstrating

the muscles of the extensor compartment of the forearm and hand. (Reprinted with permission from Moore KL, Dalley AF. Clinically Oriented Anatomy. 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 1999.)

as th eir volar counterparts. However, th ey are all bipen nate m uscles an d assist in digit abduction . Both groups of interossei are innervated by the ulnar nerve. In addition, they both help the lum bricals with MCP flexion and IP exten sion . Th e th en ar m uscles are composed of th e abductor pollicis brevis (APB), flexor pollicis brevis (FPB), and opponens pollicis (OP). The APB originates on the scaphoid an d

trapezium to in sert at th e lateral aspect of th e proxim al ph alan x of th e th um b. It is in n ervated by th e recurrent branch of the median nerve an d serves to abduct th e thum b. The FPB origin ates on th e trapezium to in sert at th e base of th e proxim al ph alan x of th e th um b. It h as two h eads: superficial an d deep. Th e superficial h ead is in n ervated by th e recurren t bran ch of th e m edian , wh ereas th e deep h ead is in n ervated by th e uln ar n erve. It aids th um b MCP flexion .

590


Deep to th ese m uscles, th e OP origin ates on th e trapezium to in sert on th e lateral aspect of th e th um b MC. It is in nervated by the recurren t branch of th e m edian n erve and serves to flex and m edially rotate th e TM. The adductor pollicis (AP) m uscle is composed of an oblique an d tran sverse h ead. Th e oblique h ead origin ates from th e capitate and base of the index and m iddle MC, whereas the transverse head originates from the distal th ird of th e in dex MC. Both h eads in sert on th e base of th e proxim al ph alan x of th e th um b. Th e AP assists in th um b adduction an d is uln arly in n ervated. The hypoth enar m uscles include th e palm aris brevis (PB), abductor digiti m in im i (ADM), flexor digiti m in im i brevis (FDMB), an d oppon en s digiti m in im i (ODM). Th e

PB origin ates on th e tran sverse carpal ligam en t (TCL) an d inserts on the undersurface of the m edial palm epiderm is. It is in n ervated by th e superficial bran ch of th e uln ar n erve and wrinkles the skin on the m edial palm . The ADM originates on the pisiform to insert on the base of th e sm all finger proxim al phalan x. It assists with sm all fin ger abduction. The FDMB originates on the ham ate and TCL to insert at the base of the sm all finger proxim al phalanx. It assists with sm all fin ger MCP flexion . Deep to th ese m uscles, th e ODM origin ates on the ham ate and TCL to insert on the m edial side of the sm all finger MC. It flexes the sm all finger MC and rotates it laterally. All of th e hypothenar m uscles, except for th e PB, are in n ervated by th e deep bran ch of th e uln ar n erve.

Figure 15.9 The extensor mechanism of the finger. (Reprinted with permission from Doyle JR and Botte MJ: Surgical Anatomy of the Hand and Upper Extremity. Philadelphia: Lippincott Williams & Wilkins, 2003.)


Ancone us

591

De e p bra nch of the ra dia l ne rve Bra chiora dia lis

P os te rior inte ros s e ous re curre nt a rte ry

Exte ns or ca rpi ra dia lis longus P la n e o f s e c tio n fo r (B)

Bra nche s of pos te rior inte ros s e ous ne rve

Exte ns or ca rpi ra dia lis bre vis P os te rior inte ros s e ous ne rve a nd a rte ry

Exte ns or digitorum

P rona tor te re s (dis ta l a tta chme nt)

Exte ns or digiti minimi

Ra dius

Exte ns or ca rpi ulna ris Abductor pollicis longus Exte ns or indicis

Exte ns or pollicis bre vis

Ou tc ro p p in g m u s c le s o f th u m b

Exte ns or pollicis longus

Dors a l ca rpa l a rch

Dors a lis indicis a rte ry

Ra d ia l a rte ry (in a na tomica l s nuff box) Dors a lis pollicis a rte rie s

Ra dia lis indicis a rte ry Adductor pollicis Ins e rtion of 1s t dors a l inte ros s e ous

Figure 15.10 Deep musculature of the

extensor compartment of the forearm. (Reprinted with permission from Moore KL, Dalley AF. Clinically Oriented Anatomy. 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 1999.)

VASCULAR Th e m ain blood supply to wrist an d h an d is via th e radial an d uln ar arteries, wh ich are term in al bran ch es of the brachial artery (Fig. 15.12). Th e ulnar artery, which is slightly larger than its radial counterpart, starts in proxim al forearm , runn ing on top of FDP and beneath both FDS an d FCU. As it travels m ore distal, th e uln ar artery is located just radial to uln ar nerve. After traversing the TCL,

it en ters th e Guyon can al. At th is poin t, it gives off th ree bran ch es—th e palm ar carpal bran ch , dorsal carpal bran ch , an d deep palm ar bran ch —before term in atin g in th e h an d as th e superficial palm ar arch . Th e deep palm ar bran ch an astom oses with th e radial artery to complete th e deep palm ar arch (see Fig. 15.12). Th e radial artery is located just lateral to th e FCR ten don from the proxim al forearm to the radiocarpal join t, wh ere it gives off th ree bran ch es—palm ar carpal bran ch , dorsal

P rope r pa lma r digita l a rte rie s

P rope r pa lma r digita l ne rve s

Ra dia lis indicis a rte ry 1s t lumbrica l

Fibrous digita l s he a th Fle xor digitorum s upe rficia lis Common pa lma r digita l a rte rie s a nd ne rve s

1s t dors a l inte ros s e ous Adductor pollicis S upe rficia l pa lma r a rch Fle xor pollicis bre vis

Abductor digiti minimi

Re curre nt bra nch of me dia n ne rve

P a lma ris a pone uros is

Abductor pollicis bre vis

P a lma ris bre vis Ulna r ne rve a nd a rte ry P is iform Dors a l ca rpa l bra nch Dors a l cuta ne ous bra nch of ulna r ne rve Fle xor ca rpi ulna ris

A

S ite of fus ion of te ndon of pa lma ris longus a nd pa lma r a pone uros is to unde rlying fle xor re tina culum (tra ns ve rs e ca rpa l liga me nt) Abductor pollicis longus S upe rficia l pa lma r bra nch Ra dia l a rte ry P a lma ris longus

Liga me nts of s kin

P a lma r digita l ne rve

2nd lumbrica l Abductor Digiti minimi

Fle xor bre vis Oppone ns

1s t lumbrica l Te ndon of fle xor pollicis longus Fle xor pollicis bre vis

Communica ting Bra nche s of ulna r ne rve

S upe rficia l

Oppone ns pollicis

De e p P is iform Fle xor re tina culum (tra ns ve rs e ca rpa l liga me nt) Ulna r ne rve a nd a rte ry

Abductor pollicis bre vis

Abductor pollicis longus

B Figure 15.11 The superficial (A) and deep (B) intrinsic hand muscles. (Reprinted with permission from Moore KL, Dalley AF. Clinically Oriented Anatomy. 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 1999.)


593

Figure 15.12 Blood supply to palmar

forearm and hand. (Reprinted with permission from Doyle JR, Botte MJ. Surgical Anatomy of the Hand and Upper Extremity. Philadelphia, PA: Lippincott Williams & Wilkins, 2003.)

carpal branch, and a superficial palm ar branch. The superficial palm ar bran ch an astom oses with th e uln ar artery to complete th e superficial palm ar arch . Th e radial artery con tinues dorsally under the APL and EPB tendons as it en ters th e an atom ic sn uffbox. After passin g th rough th e sn uffbox, it dives between the heads of the first dorsal in terosseus m uscle an d gives off two addition al bran ch es: th e

prin ceps pollicis, wh ich supplies th e th um b, an d th e radialis in dicis artery, wh ich supplies th e radial in dex fin ger. Th e rem ainder of th e radial artery term in ates in to th e deep palm ar arch . Th e deep arch gives off th ree palm ar MC arteries an d the superficial arch gives off three com m on palm ar digital arteries. Th e palm ar MC arteries join th e com m on palm ar

594


P a lma r digita l a rte rie s a nd ne rve s Fibrous digita l s he a th

Fibrous digita l s he a th P a lma r a pone uros is

P a lm a r

Hypothe na r fa s cia

Fle xor digitorum profundus te ndon Ne rve Arte ry Ve in

The na r fa s cia

P a lma ris bre vis

Fle xor re tina culum (tra ns ve rs e ca rpa l liga me nt)

P a lma ris longus te ndon

A

Fle xor digitorum s upe rficia lis te ndon

P a lm a r vie w

P a lma r digita l

Cuta ne ous liga me nt Dors a l (e xte ns or) e xpa ns ion

B

Do rs a l

Figure 15.13 Cross section of a finger showing the relationships between the tendons and surrounding neurovascular structures. (Reprinted with permission from Moore KL, Dalley AF. Clinically Oriented Anatomy. 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 1999.)

digital arteries, wh ich subsequen tly bifurcate to form th e proper palm ar digital arteries. It is importan t to n ote th at the proper palm ar digital arteries lies at the periph ery, not the center, of the fingers. O n e last take-h om e poin t regardin g th e vasculature of the fin gers is that, un like in the palm , the arteries lie deep to th e n erves. Th e latter h as implication s for iden tifyin g nerve injuries in patients with finger lacerations, for if on e determ in es an artery h as been severed, th en n erve in jury sh ould be suspected (Fig. 15.13).

NERVE ANATOMY Th e th ree m ain n erves th at supply th e h an d are th e uln ar, m edian , an d radial. Th e uln ar n erve en ters th e forearm after em ergin g from th e m edial epicon dylar groove an d piercin g the two h eads of the FCU. It runs down the length of the forearm , just radial to the ulnar artery. Before reaching the radiocarpal joint, it gives off dorsal and palm ar sensory bran ch es. After en terin g th e Guyon can al, it divides in to a superficial and deep branch . Th e superficial branch turns in to th e proper digital n erves to th e sm all fin ger an d uln ar

aspect of the rin g finger, while the deep branch provides m otor innervation to all in trinsic m uscles not inn ervated by the m edian nerve. Th e m edian n erve en ters th e forearm between th e two h eads of th e pronator teres an d quickly dives ben eath th e FDSthroughout the length of th e forearm . Just before entering the carpal tun nel at the wrist crease, it gives off a palmar cutaneous branch, wh ich supplies sen sation to th e th en ar em in en ce. Th e rest of th e m edian n erve courses th rough th e carpal tun n el an d form s a recurrent branch, which supplies m otor to th e th en ar m uscles. It is im portan t to n ote th at th e recurren t m otor bran ch is form ed before en terin g th e carpal tun n el in som e in dividuals an d th at th ere can be som e an atom ic variability. Th e rem ainder of the m edian n erve term inates in digital sen sory n erves, wh ich supply th e dorsal distal ph alan ges of th e th um b, in dex, lon g, an d radial h alf of th e rin g fin ger an d th e palm ar th um b th rough radial h alf of th e rin g fin ger. Th e radial n erve divides in to th e superficial an d deep radial n erve, wh ich becom es th e posterior in terosseus n erve, just proxim al to th e lateral epicon dyle of th e h um erus. Th e superficial radial n erve run s just beneath the brach ioradialis throughout th e length of th e forearm before em erging


595

Figure 15.14 The relationship of

Grayson and Cleland ligaments to the neurovascular bundle. NV, neurovascular; MC, metacarpal; PA, palmar aponeurosis. (Reprinted with permission from Doyle JR, Botte MJ. Surgical Anatomy of the Hand and Upper Extremity. Philadelphia, PA: Lippincott Williams & Wilkins, 2003.)

m ore superficially a few centim eters proxim al to the exten sor retin aculum . Th e superficial radial n erve is purely sen sory in fun ction and provides sensation to the dorsum of both th e wrist an d th e proxim al h alf of th e followin g digits: th um b, in dex, lon g fin ger, an d radial h alf of th e rin g fin ger. Th e digital n erves lie volarly an d at th e periph ery of th e digits. As m en tion ed previously, th ey are superficial to th e digital arteries. Th e n eurovascular bun dle is protected by two thickened ligam ents—Grayson and Cleland ligaments— wh ich are located volarly an d dorsally, respectively. Th e digital arteries an d n erves are protected by th ese ligam en ts (see Figs. 15.13 and 15.14).

PATIENT EVALUATION History Th e key to diagn osin g any h an d path ology begin s with a well-taken history. O ne should begin by obtainin g the patien t’s age, h an dedn ess, m ode of em ploym en t, an d explorin g h is or h er ch ief complain t. Typically, a patien t will complain of pain in a specific area of th e h an d. A good

strategy is to h ave th e patient localize the pain by havin g h im or h er poin t with on e fin ger to th e area of m axim al ten dern ess. Th e exam in er sh ould th en ask th e typical pain evaluation question s, wh ich in clude th e followin g: Wh en did th e pain start? Was th ere an in itial traum a? Wh at aggravates it? Wh at m akes it better? O n e sh ould in quire about a recen t travel h istory or exposures an d any relevan t m edical h istory such as rh eum atoid arth ritis (RA) or diabetes. Th e an swers to th ese question s can steer th e physician toward th e correct diagn osis. For in stan ce, golfers an d baseball players are pron e to h ook of th e h am ate fractures so kn owin g that a patient has had ulnar-sided pain in the palm region sin ce a golf outin g a few days prior can assist on e in m akin g th is diagn osis. On e sh ould also in quire wh eth er the patient is involved in worker’s compensation for this in jury, as th is patien t population h as been sh own to h ave un ique outcom es.

Physical Examination As in any m edical field, th e physical exam in ation of th e h an d sh ould begin with in spection . On ce in spection is com plete, on e sh ould proceed with palpation an d ran ge of m otion of all join ts of th e h an d, especially th e area of

596


m axim al ten dern ess. Radial pulse an d capillary refill tim e sh ould be explored. Motor an d sensory function of th e m edian , uln ar, an d radial n erve sh ould be tested. Grip an d pin ch stren gth can also be quan tified.

Radiographic Evaluation Radiograph ically, th e in itial in vestigation begin s with plain radiographs showing th ree views of the hand and/or finger (an teroposterior or posteroan terior [PA], lateral, oblique) depen din g on th e circum stan ces. Occasion ally, a special view m ay be requested depen din g on th e patien t’s symptom atology an d th e suspected diagn osis. For example, if th e clinician is worried about a h ook of the ham ate fracture, he or sh e m ight request a carpal tunnel view, wh ich provides a better view of th e h ook itself. An oth er importan t addition al view is th e scaphoid view, wh ich is sh ot with th e wrist in uln ar deviation . Uln ar deviation causes scaph oid to exten d, wh ich places it in th e plan e of th e radius, m akin g it easier to evaluate for fracture. More soph isticated im agin g m ay be n ecessary for certain types of suspected in juries. For example, a patien t with un explain ed an atom ic sn uffbox ten dern ess 2 weeks after a fall on to an outstretch ed h an d m igh t m erit a m agn etic reson an ce im agin g (MRI) scan to rule out a scaph oid fracture. MRI can also be useful for evaluation of TFCC tears, scapholunate ligam ent disruption , or suspected avascular necrosis of a carpal bone. CT scan can be useful for evaluatin g bon e in juries such as in traarticular distal radius fractures or h ook of th e h am ate fractures.

TRAUMATIC INJURIES TO THE HAND AND WRIST Th e h an d is a frequen t recipien t of traum a. Fractures of th e bon es in th e h an d are am on g th e m ost com m on in th e body. Because our h an ds are essen tial to m any of our everyday activities, deform ity or loss of fun ction is n ot well tolerated.

Presentation and Physical Examination Patients typically complain of pain an d swelling over the distal ph alan x after traum a to th e fin ger. On exam in ation , the patien t will have tendern ess over the distal phalanx and m ay have a con com itant nail bed injury. If th e fracture is intraarticular, the patient m ay not be able to actively flex or exten d th e DIP. Radiographic Findings/Special Studies Plain an teroposterior, lateral, an d oblique radiograph s of the finger will dem onstrate a visible fracture line. Treatment Treatm ent varies dependin g on the type of distal phalan x fracture. Because of their surrounding soft tissue envelope, tuft fractures are usually stable and can be treated non operatively with an alum inum finger splint. However, soft tissue injury can often be a concern with these injuries, especially dam age to th e un derlyin g n ail bed. Classically, th e teach in g is th at if th ere is a subungual hem atom a in volvin g greater than 50% of the nail bed, the physician sh ould rem ove the n ail plate an d repair th e sterile m atrix, alth ough th is issue rem ain s con troversial. Distal ph alan geal sh aft fractures can usually be treated n on operatively with alum in um splin tin g un less th ey are sign ificantly displaced or unstable, in wh ich case they m ay require percutan eous pin n in g (Fig. 15.15). Beware of distal ph alan geal sh aft fractures in ch ildren wh o go th rough th e physis (Salter I fractures), kn own as Seymour fractures. These are often associated with open nail bed injuries and are susceptible to in fection if m issed. Distal ph alan x in traarticular fractures are m ore difficult to treat and m ay require operative fixation if the fracture fragm en t is large or if it is attach ed to either the FDP or term in al exten sor ten don . Wh en th e term in al exten sor

FRACTURES AND DISLOCATIONS Distal Phalangeal Fractures Th e distal ph alan x is on e of th e m ost frequen tly fractured bon es in th e body.

Classification Distal ph alan x fractures are classified on th e basis of location , in to th ree types: tuft, sh aft, an d in traarticular. Mechanism of Injury Fractures of th e distal ph alan x are gen erally th e result of a crush injury.

Figure 15.15 Distal phalanx fracture. (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)


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Mechanism of Injury Th e typical m ech an ism s are crush in jury an d axial load.

A

B

C

D

Presentation and Physical Examination Th e patien t typically complain s of pain an d swellin g over th e affected ph alan x after a traum atic even t. On exam in ation, the patient will have ten derness and swelling over the affected phalan x with decreased range of m otion. Radiographic Findings/Special Studies Plain PA, lateral, an d oblique radiograph s of th e h an d will dem on strate a visible fracture lin e. Treatment Non displaced or even m in im ally displaced fractures can be treated nonoperatively with buddy tape, alum inum splinting, or even casting. If a cast or splint is applied, one m ust keep the wrist in 20 degrees of extension with fingers in in trinsic plus position (i.e., MCP joints flexed with IP joints in full extension). This position preven ts th e MCP collateral ligam ents (due to the CAM effect of th e MC heads) and IP volar plates from sh orten in g. Fractures th at are m ore severely displaced, rotated, com m inuted, or display m ore th an 10 to 20 an gulation in any plan e often require operative fixation. They can be stabilized with screws, Kirshner wires, plates, or extern al fixation .

Phalangeal Dislocations E Figure 15.16 (A–E) Technique of extension block pinning.

(Reprinted with permission from Bucholz RW, Heckman JD, CourtBrown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

ten don is attach ed to th e avulsed fragm en t, th e in jury is often referred to as a bony mallet finger. Th is in jury frequen tly requires closed reduction an d percutan eous pin n in g, especially if greater th an 50% of the joint surface is in volved or there is DIP joint subluxation (Fig. 15.16). The m ajority of in juries th at in volve an FDP avulsion fracture h ave to be repaired surgically to restore th e flexion m ech an ism of th e fin ger.

Proximal and Middle Phalangeal Fractures Fractures of th e proxim al an d m iddle ph alan x are also com m on .

Classification Fractures of th e proxim al an d m iddle ph alan x can be divided into the following types based on anatom ic location: base, sh aft, n eck, an d con dylar (Fig. 15.17)

Classification Ph alan geal dislocation s are classified as dorsal, volar, rotatory, or lateral. Mechanism of Injury Th ese in juries are com m on ly th e result of an axial load to an extended digit. Presentation and Physical Examination Th e patien t will often complain of pain an d difficulty m oving th e involved joint. Th e patien t will h ave ten dern ess over affected join t, an obvious deform ity, an d reduced active an d passive m otion of th e join t. Radiographic Findings/Special Studies Plain an teroposterior, lateral, an d oblique radiograph s of th e in volved fin ger will dem on strate dorsal, volar, or lateral dislocation of th e m ore distal ph alan x relative to th e m ore proxim al ph alan x (or MC). Treatment DIP dislocation s are com m on ly dorsal an d easily reduced. PIP dislocation s can be volar, dorsal, or lateral an d are also easily reduced, usually with a m an euver con sistin g of gen tle traction and volar or dorsal pressure on the m iddle phalanx (Fig. 15.18). Rotational PIP dislocations can be irreducible by closed m ethods and m ay require surgical intervention.

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A

Figure 15.17 (A) Intraarticular fracture of the head and (B) an

oblique shaft fracture. (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

MCP dislocation s are less com m on but often m ore difficult to treat. With a dorsal MCP dislocation , a n oose can be form ed aroun d the MC head by the flexor tendon ulnarly an d th e lum brical radially. In th is scen ario, lon gitudin al traction can cause th e volar plate to becom e en trapped in the joint, m aking closed reduction impossible. Reduction is best ach ieved with application of force from dorsal to volar over th e base of th e proxim al ph alan x. Wh en reduction can not be afforded by this m aneuver, open reduction via a

B

dorsal approach is often required to rem ove th e in terposed volar plate.

Metacarpal Fractures Th e MCs are com m on sites of in jury in th e h an d. Th ey are often in jured durin g physical altercation s wh en on e in dividual attempts to pun ch another person or object with a closed fist.

A

B Figure 15.18 (A) Dorsal proximal interphalangeal dislocation and (B) subsequent reduction. (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)


Figure 15.19 Oblique fracture of metacarpal shaft with shortening. (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Classification MC fractures are classified on th e basis of anatom ic location as h ead, neck, shaft, an d base (Fig. 15.19). Mechanism of Injury Th e fractures are typically th e result of eith er a crush in jury or an axial load to th e MC (e.g., wh en pun ch in g an object with a clen ch ed fist). Presentation and Physical Examination Patients typically complain of pain an d swelling over the affected MC after an in jury. Patients typically dem onstrate ten dern ess an d swellin g over th e affected MC. Th e MC h ead m ay be depressed, giving the appearance of a “m issing knuckle.’’ Radiographic Findings/Special Studies Plain PA, lateral, an d oblique radiograph s of th e h an d will dem on strate a visible fracture lin e. A Brewerton view can be h elpful to evaluate for collateral ligam en t avulsion fractures. It is taken with the MP joints flexed 60 to 70 degrees, the dorsal surfaces of th e digits placed flat on the x-ray cassette, and the beam angled 15 degrees radial.

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Treatment MC h ead fractures are relatively uncom m on but when they occur, th ey are often difficult to treat an d gen erally require operative stabilization . A simple fracture pattern can be m an aged effectively with eith er closed reduction an d percutan eous pin n in g or open reduction in tern al fixation (ORIF). Com m inuted fractures can be m anaged sim ilarly but h ave poorer outcom es an d m ay require future arth roplasty. Fractures of th e MC n eck are relatively frequen t. Th ey carry th e eponym “boxer’s fractures’’because of th eir m ech anism , wh ich is an axial load across a clenched fist. MC n eck fractures generally assum e an apex dorsal an gulation deform ity. Th ey m ay also exh ibit rotation al deform ity, wh ich is importan t to n ote as it m ay m erit reduction even if angulation is m in im al. Criteria for acceptable an gulation varies dependin g on the source, but m any surgeons use the 10 –20 –30 –40 rule in wh ich 10 degrees is acceptable for th e index finger, 20 for the long, 30 for the ring, and 40 for th e sm all. Th ere is little eviden ce in th e literature regarding what “acceptable’’ angulation is, and there are som e biom ech an ical data for th e sm all fin ger MC th at suggest th at an gulation of m ore th an 30 degrees leads to sign ifican t dysfun ction of th e flexor system . If displacem en t is greater th an th e accepted degree for a particular fin ger, a closed reduction is warran ted. A com m on ly applied tech n ique is th e Jahss maneuver, in wh ich th e affected digit is volar flexed to 90 degrees and a volar to dorsal force is applied through th e proxim al ph alan x so as to restore th e n orm al align m en t of th e MC n eck (Fig. 15.20). Any rotation al deform ity can also be corrected while perform ing th is m aneuver. Aplaster spin t or cast sh ould be applied to m aintain this reduction with th e affected digit in a 90 degree volar flexed position , wh ich serves to m ain tain reduction an d preven t th e MC h ead collateral ligam ents from sh orten in g. As reduction is often difficult to m ain tain in a splin t or cast, th ese fractures m ay require a repeat reduction with percutan eous pinning in the operating room setting. As noted earlier, MC shaft fractures are typically the result of eith er an axial load or a crush injury. Th ey generally create an apex dorsal an gulation deform ity due to th e vector of pull of th e interosseus m uscles, wh ich is volar (Fig. 15.21). Most clin ician s consider n onoperative treatm en t in a spint or cast if sagittal plane deform ity is less than 30 degrees an d th ere is n o sign ifican t rotation al m alalign m en t. In gen eral, un stable MC sh aft fractures require operative fixation, which consists of percutaneous pinning versus ORIF with plates and/ or screws. It is important to be aware th at m ultiple MC sh aft fractures in th e sam e h an d can result in a com partm ent syn drom e, in which the patient will presen t with a very swollen pain ful h an d h eld in th e intrinsic minus (MP join t exten sion an d IP join t flexion ) position . Fractures of th e MC base are less com m on th an in th e n eck but can be m ore problem atic, particularly when in traarticular. The often involve the thum b an d sm all finger.

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A

B

Figure 15.22 Bennett fracture (A) and Rolando fracture (B).


Figure 15.20 Jahss maneuver for reducing metacarpal neck

fractures. (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

An in traarticular fracture at the base of the thum b MC is often referred to as a Bennett fracture (Fig. 15.22). Th is in jury is typically caused by axial load to flexed thum b. Deform ity an d difficulty with h ealin g is th e result of th e fact th at th e APL pulls the thum b MC shaft radially an d dorsally while the deep volar oblique (beak ligament) rem ains attached to the ulnar-sided fragm ent. Of note, the eponym “Rolando fracture’’is used when there is com m inution at the thum b MC base an d both an uln ar an d radial fragm en t are visible. Last, a “baby Bennett’’is the term used for an intraarticular fracture at the base of the sm all fin ger MC. In this scenario,

A

B Figure 15.21 Ring and small finger metacarpal fracture (A) status post open reduction internal

fixation (B). (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)


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the ECU pulls the sm all finger MC sh aft uln arly, m akin g healing difficult. Each of th ese intraarticular MC base fractures generally require percutaneous pinning versus O RIF.

Gamekeeper’s Thumb Ligam entous in jury involving the MCs occurs quite frequen tly, with th e MCP join t of th e th um b bein g th e m ost vuln erable due to its hyperm obility. Classically, gamekeeper’s thumb refers to ch ron ic atten uation of th e uln ar collateral ligam ent, while skier’s thumb refers to acute rupture of th e ligam en t.

Mechanism of Injury Radial-directed stress on th e th um b MCP join t can dam age the uln ar collateral ligam en t, resulting in a gam ekeeper’s thum b. Presentation and Physical Examination Th e patien t typically complain s of pain an d in stability at the thum b MCP joint. O n exam in ation , th e patien t will h ave ten dern ess to palpation at th e uln ar aspect of th e th um b MCP join t an d will have gapping at the joint with radial stress. The joint sh ould be stressed in full exten sion an d in 30 degrees of flexion . Compared with th e con tralateral side, greater than 35 degrees of in creased an gulation in exten sion or greater th an 15 degrees of increased angulation in flexion is diagnostic. Radiographic Findings Stan dard an teroposterior, lateral, an d oblique radiograph s of th e th um b m ay dem on strate a bony fleck in th e region of th e th um b MCP represen tin g th e avulsion of th e uln ar collateral ligam en t. Special Studies Stress radiograph s of th e th um b with a radial-directed force m ay reveal gapping at th e MCP join t. Ultrasonography and MRI can also h elp in establishing the diagnosis. Treatment Patients who dem on strate m inim al gapping with radial stress are likely to h ave only a partial uln ar collateral ligam en t rupture, which can be treated with th um b spica casting for 6 weeks. However, gapping with radial stress greater than 35 degrees in extension or greater than 15 degrees in 30 degrees of flexion suggests a com plete rupture. In com plete tears, th e ligam en t can becom e lodged beh in d AP aponeurosis, which prevents healing (known as a Stener lesion) (Fig. 15.23). Th erefore, early surgery is advocated for complete tears.

CARPUS Scaphoid Fractures Th e scaph oid is th e m ost frequen tly fractured bon e in th e carpus and the slowest to heal. Scaphoid fractures are fre-

Figure 15.23 Stener lesion in gamekeeper’s thumb. (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

quen tly m issed sin ce th ey often can n ot be visualized on in itial radiographs and require close follow-up for detection. All scaph oid fractures can be problem atic but fractures of th e proxim al pole are th e m ost worrisom e. Sin ce th e scaph oid h as a retrograde blood supply from the radial artery, which enters m ainly on its dorsal ridge, the proxim al pole is particularly susceptible to avascular necrosis wh en fractured.

Classification Fractures of scaphoid are often described on th e basis of anatom ic location as tubercle, proxim al pole, waist, or distal pole (Fig. 15.24). Mechanism of Injury Th e scaph oid is typically in jured by a fall on to an outstretch ed h and. Presentation and Physical Examination Th e patien t will typically complain of pain over th e region of th e an atom ical sn uffbox after a fall. Th e patien t often h as radial-sided swellin g an d pain with m ovem en t. Frequen tly, th ere is ten dern ess to palpation dorsally over th e anatom ical snuffbox or volarly over the scaph oid tubercle. Radiographic Findings Standard radiographic evaluation of the scaphoid begin s with th ree plain radiograph views of th e wrist, wh ich in clude a PA, lateral, an d oblique.

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Tuberosity fracture

Waist fracture

Proximal fracture pole

Figure 15.24 The classification of scaphoid fractures based on

anatomical location. (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Special Studies To better visualize th e scaph oid, on e can request a “scaphoid view’’ of the wrist, which is a PA shot with approxim ately 20 degrees of uln ar deviation . Uln ar deviation rotates th e scaph oid in to th e sam e axis as th e radius an d m in im izes overlap between th e waist an d tubercle, allowin g on e to visualize th e scaph oid alon g its en tire len gth (Fig. 15.25). Sin ce scaph oid fractures m ay n ot sh ow up on in itial radiograph s, any patien t wh o com plain s of an atom ic sn uffbox pain after traum a to th e h an d/ wrist sh ould be placed in th um b spica splin t an d sh ould be followed up for repeat radiographs in 2 to 3 weeks (Fig. 15.26). At that tim e, bone

Normal conjunct rotation

Radial deviation

Neutral

Ulnar deviation

Figure 15.26 Radiograph of a very subtle scaphoid fracture that

could easily be missed. (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Normal synchronous flexion/extension Extension

Neutral

Flexion

Figure 15.25 The kinematics of the prox-

imal carpal row during radial/ulnar deviation and flexion/extension. (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)


A

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B Figure 15.27 A clear scaphoid fracture on magnetic resonance imaging (A), which is difficult to

see on plain radiograph (B). (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

resorption m ay be eviden t if th ere was in deed a fracture. One radiographic clue suggesting a possible scaphoid fracture is alteration of the navicular fat stripe, wh ich is a th in radiolucen t lin e just radial to th e scaph oid. It is presen t in norm al individuals an d m ay becom e displaced or obliterated secondary to a scaphoid fracture. Ultim ately, one m ay need either MRI or CT scan of the wrist with 1 m m cuts through plane of scaph oid to diagnose an occult scaphoid fracture (Fig. 15.27). Bone scan is an oth er useful diagnostic test but is used less frequen tly th an MRI or CT.

Treatment As note earlier, scaphoid fractures com e in four varieties: tubercle, proxim al pole, waist, and distal pole. In general, scaphoid fractures are treated on th e basis of displacem en t; however, som e surgeons choose to surgically fix all proxim al pole fractures to m inim ize the ch ances of avascular necrosis. Nondisplaced fractures can be treated with a thum b spica cast. Som e surgeons place patients in a long arm thum b spica for 6 weeks, after which they are placed in a short arm thum b spica until the fracture has healed. Th ese fractures can take from 3 to 6 m on th s to h eal. Waist fractures average approxim ately 12 weeks to heal, whereas proxim al pole fractures gen erally take approxim ately 20 to 25 weeks. Because of th ese prolon ged h ealin g tim es, patients m ay be given a choice of surgical fixation even for nondisplaced injuries. Displaced scaph oid fractures require operative fixation , usually with a h eadless compression screw. O th er criteria for fixation include scapholunate angle of greater than 60 degrees an d radiolun ate an gle of greater th an 15 degrees. Th e procedure can be don e eith er percutan eously or open . If don e open , m ost surgeon s advocate a volar approach for waist to distal pole fractures and dorsal approach for waist to proxim al pole (Fig. 15.28).

Delayed un ion an d n on un ion are of particular con cern in scaph oid fractures. Som e support th e use of electrical bon e stim ulator for n on displaced fractures. Th e stan dard of care for a displaced n on un ion is bon e graftin g an d screw fixation . Bon e graftin g option s in clude can cellous, corticocan cellous, an d vascularized. Can cellous bon e graftin g is usually used for n on displaced n on un ion s. However, in m any scaph oid fractures, volar com m in ution in th e area of th e waist can cause an apex dorsal or “h umpback’’ deform ity. In cases like these, a corticocancellous wedge of bon e graft m ust be placed volarly to correct th e deform ity.

Figure 15.28 Proximal pole fracture of the scaphoid treated

with open reduction and internal fixation via a dorsal approach. (Reprinted with permission from Bucholz RW, Heckman JD, CourtBrown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

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Fin ally, fractures of th e proxim al pole or th ose dem on stratin g avascular necrosis m ay require vascularized bon e grafts. Th e m ost com m on ly used is th e distal radius vascularized bon e graft based on th e 1,2 intercompartm en tal supraretin acular artery, wh ich h as dem on strated un ion rates of approxim ately 70%. More recently, som e centers have attempted free vascularized grafts from the m edial fem oral condyle.

Lunate Fractures Th e lun ate is th e fourth m ost com m on ly fractured bon e in the carpus. Sim ilar to th e scaph oid, it has a tenuous blood supply th at can be disrupted when a fracture occurs.

Classification Th ere are five types of lun ate fractures: palm ar pole, osteoch on dral ch ip, dorsal pole, sagittal oblique, an d coron al split. Mechanism of Injury Th e typical m ech an ism is a fall on to an outstretch ed, hyperexten ded wrist. Presentation and Physical Examination Patien ts often complains of central wrist pain and/ or pain with wrist m ovem en t after a fall. Physical findin gs in clude ten dern ess to palpation in th e cen ter of th e wrist an d pain with wrist range of m otion .

sclerosis of th e lun ate. Stage III involves sclerosis and fragm entation of th e lunate and is divided into A and B based on eith er th e absen ce (A) or presen ce (B) of fixed scaph oid rotation . Stage IV is degen erative arth ritis of th e adjacen t intercarpal join ts. In term s of treatm en t, Stage I can be treated with im m obilization, whereas stages II through IIIA m ay require revascularization an d joint leveling procedures (e.g., uln ar len gth enin g, radial sh orten in g) or even carpal fusion s, wh ich h elp to un load th e lun ate. With fixed rotation of th e scaphoid, a proxim al row carpectomy (PRC) or intercarpal fusion m ay be indicated. Finally, with stage IV disease, a total wrist fusion or PRC is recom m ended.

Triquetral Fractures Triquetral fractures are the second m ost com m on type of carpal fracture behin d fractures of the scaphoid.

Classification Th ere are two types of triquetral fractures: dorsal rim ch ip fractures, which are the m ost com m on, and body fractures. Mechanism of Injury Wrist hyperflexion with radial deviation is a com m on cause of dorsal ch ip fractures, wh ereas triquetral body fractures are often caused by direct traum a.

Radiographic Findings Stan dard PA, lateral, an d oblique radiograph s of th e h an d m ay be n egative.

Presentation and Physical Examination Th e patien t complain s of pain an d swellin g about th e uln ar wrist after traum a. Th e patien t typically h as uln ar-sided wrist ten dern ess an d pain with wrist range of m otion .

Special Studies CT of th e wrist m ay h elp to delin eate a lun ate fracture if plain radiograph s are n egative. MRI is in dicated if Kien bock disease (osteon ecrosis of th e lun ate) is suspected.

Radiographic Findings/Special Studies Stan dard PA, lateral, an d oblique radiograph s of th e h an d sh ould be obtain ed. Dorsal chip fractures can best be seen on th e lateral radiograph .

Treatment In gen eral, m in im ally displaced lun ate fractures can be treated with 4 to 6 weeks of im m obilization in a sh ort or lon g arm cast. Fractures associated with in traarticular in congruity or instability are gen erally treated with ORIF.

Treatment Sm all dorsal ch ip triquetral fractures an d m in im ally displaced body fractures can typically be treated with 4 to 6 weeks of cast im m obilization . If the fragm ent is sizable, it results in in stability, or if it is sign ifican tly displaced, O RIF m ay be indicated.

Complications O f n ote, on e of th e poten tial an d m ore devastatin g com plications of lunate traum a is Kienbock disease. It is believed that traum a, which can be acute or ch ronic from repetitive stress (e.g., as in patients with negative uln ar varian ce, which causes in creased stress on th e lunate), disrupts the ten uous blood supply of th e lun ate, leadin g to avascular necrosis. MRI or bon e scan should be obtained if there is any suspicion . Th is disease an d its severity can be ch aracterized by th e Lichtman classification system. Th is system is based on plain radiograph appearan ce an d divides Kien bock disease in to four stages. Stage I represen ts n o visible ch an ges in th e lun ate on plain film , on ly MRI. Stage II is

Trapezium Fractures Trapezial fractures are the third m ost com m on carpal fracture.

Classification Th ere are five types of trapezium fractures: vertical tran sarticular, horizon tal, dorsoradial tuberosity, anterom edial ridge, an d com m in uted. Mechanism of Injury Th e m ost com m on m ech an ism is an axial load to th e TM.


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Presentation and Physical Examination Th e patien t typically complain s of pain an d swellin g at th e base of th e th um b after traum a. O n exam in ation , th e patient will have ten derness over th e base of the thum b and pain with th um b ran ge of m otion . Radiographic Findings/Special Studies Stan dard PA, lateral, an d oblique radiograph s of th e h an d sh ould dem onstrate th e fracture. Treatment Minim ally displaced trapezial fractures can be treated with cast im m obilization for 3 to 6 weeks. Displaced, intraarticular fracture m ay require ORIF. Anterom edial ridge fractures often result in pain ful n on un ion an d frequen tly m ust be excised.

Capitate Fractures Capitate fractures are rather rare but often have poor outcom es.

Classification Th ere are four types: tran sverse body, tran sverse proxim al pole, coron al oblique, an d parasagittal.

Figure 15.29 Small finger flexor rupture due to hook of hamate

malunion. (Reprinted with permission from Doyle JR, Tornetta P, Einhorn TA. Orthopaedic Surgery Essentials: Hand and Wrist. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

m ay result in painful nonunion. The resultant deform ity of th e h ook can lead to rupture of adjacen t rin g an d sm all finger flexor tendons over tim e (Fig. 15.29).

Mechanism of Injury Th e m ost com m on m ech an ism of in jury is an axial load on a hyperexten ded wrist.

Classification Ham ate fractures can in volve either the body or hook, the latter of which is exceedingly m ore com m on.

Presentation and Physical Examination Th e patien t typically complain s of cen tral wrist pain after a fall. Ten dern ess can gen erally be elicited over th e cen ter of the carpus.

Mechanism of Injury Ham ate fractures can result from a direct blow to the h am ate or from chronic repetitive impact (Fig. 15.30).

Radiographic Findings/Special Studies Stan dard PA, lateral, an d oblique radiograph s of th e h an d sh ould dem onstrate th e fracture; h owever, CT m ay be required to better visualize th e fracture lin es. Treatment Non displaced fractures can be treated with cast im m obilization. Displaced or intraarticular fractures can be treated with K-wires or ORIF. Proxim al pole fractures are particularly difficult to m an age. Even if n on displaced, th ey can result in avascular n ecrosis due to a ten uous blood supply, wh ich , sim ilar to th at of th e scaph oid, is retrograde. Capitate fractures can occur con com itan tly with fractures of th e scaphoid. Scaphocapitate syndrome is a term used to describe a scaphoid waist fracture and associated capitate neck fracture. This in jury usually occurs via a wrist hyperdorsiflexion m echanism and requires ORIF to prevent m igration of the proxim al capitate.

Hamate Fractures Hook of h am ate fractures are m ost frequently seen in th ose wh o en gage in stick or racquet sports, such as golfers an d baseball players. Th ese fractures can be difficult to h eal an d

Figure 15.30 The mechanism for hook of the hamate fractures. (Reprinted with permission from Bucholz RW, Heckman JD, CourtBrown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

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Presentation and Physical Examination Th e patien t complain s of uln ar-sided pain distal an d radial to th e pisiform after sustain in g acute or repetitive traum a. Patien ts dem onstrate tendern ess over the ulnar side of th e wrist, dim inished grip stren gth , an d possibly paresth esias in th e uln ar n erve distribution . Th e h ook of th e h am ate can be palpated by the exam iner by placing h is/ her own thum b IP joint on the patient’s pisiform and then palpatin g 45 degrees radial an d distal. This is usually the poin t of m axim al ten dern ess.

Presentation and Physical Examination Th e patien t typically complain s of uln ar-sided wrist pain an d will exhibit ten derness to palpation directly over the pisiform . Radiographic Findings/Special Studies Stan dard PA, lateral, an d oblique radiograph s of th e h an d sh ould dem on strate th e fracture adequately. If not, a CT scan can be considered. Treatment Th ese fractures can gen erally be treated in a sh ort arm cast but m ay require excision if a pain ful n on un ion develops.

Radiographic Findings/Special Studies Th e h ook of th e h am ate can be visualized by a carpal tunnel view, wh ich is an axial view of th e wrist at m axim al dorsiflexion, or by CT scan, which is m ore accurate.

Distal Radius Fractures

Treatment Non displaced h am ate body fractures can be treated with cast im m obilization , whereas displaced or unstable fractures m ay require excision of th e fractured h ook, or rarely O RIF. It is gen erally recom m en ded th at displaced fractures or n on un ion s of th e h ook be excised.

Distal radius fractures are com m on , represen tin g up to 15% of all fractures in th e upper extrem ity. Th ey are seen frequen tly in youn g, active patien ts as a result of a h igh -en ergy traum a or elderly, osteoporotic patients as a fragility fracture. In both groups of patien ts, restoration of norm al wrist function is the guiding principle for treatm en t. Internal fixation with plating of these fractures h as becom e in creasingly popular over th e past decade.

Pisiform Fractures Pisiform fractures are rath er un com m on in juries seen in the carpus.

Classification A variety of classification system s exist, in cluding the Frykm an and Melon e, but there is no gen eral con sensus as to wh ich on e sh ould be used (Fig. 15.31). In gen eral, distal radius fractures are referred to by certain eponym s, wh ich include Colles (dorsal displacem ent), Sm ith (volar displacem en t), Barton (radial rim fracture with eith er volar or dorsal displacem en t of th e carpus), or Ch auffeur fractures

Classification Th ere are four types: tran sverse (m ost com m on ), parasagittal, com m in uted, an d pisotriquetral impaction . Mechanism of Injury Th e typical m ech an ism is direct traum a to th e pisiform .

Type I

Type IIA

Type IIB

3

3 3 1

2 4

3

4

1 4

4

Type III

1

Type IV

Type V

3 1

1

4 Figure 15.31 The Melone classification for distal radius fractures. (Reprinted with permission from

Bucholz RW, Heckman JD, Court-Brown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)


(radial styloid). Distal radius fractures are also classified on the basis of whether they are intra- or extraarticular.

Mechanism of Injury Th ese gen erally occur by a fall on to an outstretch ed h an d. Presentation and Physical Examination Th e patien t complain s of pain an d swellin g over th e wrist after a fall. On exam ination, the patient will exhibit tendern ess over th e wrist with lim ited ran ge of m otion . A detailed n eurovascular exam in ation m ust be perform ed, with special attention given to the m edian nerve. Patients wh o presen t with n um bn ess in th e m edian n erve distribution often h ave im proved symptom s after fracture reduction . However, on occasion , patients develop progressive deterioration of m edian n erve fun ction , wh ich is suggestive of acute carpal tunnel syndrom e (CTS). In these situations, any restrictive dressings, splin ts, and/ or casts should be rem oved, and the wrist should be placed in a neutral position. If the symptom s do not improve, the patient should be taken to th e operatin g room for an em ergen t carpal tun n el release. Radiographic Findings/Special Studies Stan dard an teroposterior, lateral, an d oblique views of th e wrist are in itially obtain ed. In cases in wh ich th e fracture is com m inuted or intraarticular, a CT scan can be obtained to assist with preoperative plan n in g. Treatment Treatm ent options for distal radius fractures differ depen ding on several variables, such as a patien t’s age, activity level, an d occupation. However, the degree of displacem ent is the m ost important factor that influen ces m anagm ent. Recall from th e anatomy section th at the distal radius is tilted volarly at an angle of approxim ately 11 degrees. Its angle of radial in clin ation is rough ly 22 degrees wh ile its h eigh t radially is approxim ately 11 m m relative to its m ost uln ar surface. Th ese n um bers are importan t in determ in in g wh eth er a reduction, open or closed, is n ecessary. However, even after reduction , fractures h ave a ten den cy to return to th eir initial displacem en t. Alth ough n o consensus exists, m ost would con sider acceptable align m en t in a h ealthy, active patien t to be up to 10 degrees of dorsal tilt (20 degrees from norm al), less than 2 m m of in traarticular step-off at radiocarpal joint, less than 5 m m of radial shortenin g, a congruen t DRUJ, an d m ore th an 15 degrees of radial in clin ation . If closed reduction is warran ted, th e reduction m an euver m ay vary depending on the nature of the fracture. The gen eral prin ciple is to recreate th e m ech an ism th at caused the deform ity. For example, a Colles fracture occurs via a wrist hyperextension m echanism ; th erefore, when reducing these fractures, one sh ould not simply pull lon gitudinal traction on the wrist but hyperextend it so as to lever the dorsally displaced fragm en t back in to position . Con versely, for a Sm ith fracture, a wrist hyperflexion reduction m aneu-

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ver m igh t be employed. On ce reduction is ach ieved, th e patien t sh ould be im m obilized in sugar ton g plaster splin t. A few notable complications can occur after a distal radius fracture, both in th e short and lon g term . In the sh ort term , one can develop an acute CTS, especially after repeated closed reduction attempts. In acute CTS, th e patien t typically develops a sudden n um bn ess in th e m edian n erve distribution several h ours after th e in jury and this n um bn ess gets progressively worse. Wh en th is occurs, im m ediate carpal tun n el release is in dicated. O f n ote, acute CTSsh ould be distin guish ed from m edian n erve con tusion . Un like acute CTS, m edian nerve con tusion causes n um bn ess in the m edian n erve distribution at th e tim e of injury that does n ot get progressively worse. A lon g-term com plication th at can occur, particularly with non displaced distal radius fractures, is rupture of the EPL tendon. This is attributed to isch em ia of th e ten don secon dary to th e pressure exerted by th e fracture h em atom a. Wh en closed reduction tech n iques fail to h old th e distal radius in acceptable align m en t, surgery is in dicated. Th e use of percutan eous pin n in g to augm en t closed reduction is a m eth od m ore appropriate for youn ger patien ts with extraarticular fractures. Advan ces in low profile an d locked platin g h ave m ade eith er volar or dorsal platin g a m ore com m only used option for distal radius fractures in adults (Fig. 15.32). Th e decision of wh eth er to approach th e fracture from volar or dorsal is depen den t on fractures pattern an d surgeon preferen ce. Extern al fixation m ay be in dicated for h igh ly com m in uted distal radius fractures in wh ich th ere is sign ifican t bony or soft tissue loss.

Figure 15.32 A volar distal radius plate. Note that the more dis-

tal the plate placement, the more likely a screw will penetrate the articular surface. (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

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O f n ote, a related fracture pattern seen in th e distal forearm is the Galeazzi fracture, in wh ich a distal radial sh aft fracture occurs in com bination with a DRUJ dislocation. Th is in jury requires ORIF of radial sh aft with possible percutaneous pinning of the DRUJ, depen ding on the stability of th e DRUJ after closed reduction .

Distal Forearm Fractures Ulnar Shaft Fractures Isolated uln ar sh aft fractures, also kn own as nightstick fractures, are com m only seen fractures of th e distal forearm . Classification Th ere is n o un iversal classification system for uln ar sh aft fractures. Th e fracture is described on the basis of its location an d ch aracteristics. Mechanism of Injury Ulnar shaft fractures typically occur by a direct traum a to the ulna, such as when one is struck by a n igh tstick while raising his or h er arm in defense (hence th e eponym “nigh tstick fracture’’). Presentation and Physical Examination Patien ts complain of pain over the uln ar aspect of the forearm after traum a. Ten dern ess usually is foun d over th e uln a an d pain is worsen ed with supin ation / pron ation . Radiographic Findings/Special Studies Stan dard an teroposterior an d lateral radiograph s of th e forearm will dem onstrate a visible fracture line. Treatment If n on displaced, uln ar sh aft fractures can be treated with a lon g arm cast for 6 to 8 weeks. If an gulated greater th an 10 degrees or displaced greater th an 50% of th e sh aft, m ost surgeons would advocate ORIF by using a 3.5 m m dynam ic compression plate.

Radial Shaft Fractures Th e radial sh aft is less com m on ly fractured in isolation than the ulnar sh aft. Classification Th e classification of radial sh aft fractures is largely descriptive. Mechanism of Injury Th e typical m ech an ism is a h igh -en ergy direct traum a to forearm .

Presentation and Physical Examination Th e patien t complain s of severe forearm pain after traum a. Th e patien t will exh ibit con siderable ten dern ess over th e forearm , accompan ied by swelling. A compreh ensive neurovascular exam in ation sh ould be perform ed, an d th e forearm should be exam in ed carefully for signs of com partm en t syn drom e. Th e DRUJ sh ould be exam in ed for stability by pronatin g and supin ating th e forearm an d directly stressin g th e distal radiouln ar articulation . Radiographic Findings/Special Studies Standard anteroposterior an d lateral radiographs of th e forearm and the wrist are essential to both identify the fracture and rule out DRUJ instability. Treatment Th is in jury usually occurs as a result of a h igh -en ergy m ech anism and can cause significant soft tissue traum a. In the pediatric population , th ese fractures can be treated with closed reduction an d lon g arm castin g. In adults, O RIF is typically required. O f note, if the radial shaft fracture occurs in com bination with a DRUJ dislocation , wh ich is known as a Galeazzi fracture, ORIF of radial sh aft with possible percutan eous pin n in g of th e DRUJ is n ecessary, depen din g on th e stability of th e DRUJ after treatm en t of th e radial sh aft.

Ulnar and Radial Shaft Fractures Fractures of both th e uln ar an d radial sh afts, kn own as both bone forearm fractures, are m ore com m on than isolated fractures of eith er the radius or ulna. Classification Th e classification of both bon e forearm fractures is largely descriptive. Mechanism of Injury Th e typical m ech an ism is a h igh -en ergy direct traum a to forearm . Presentation and Physical Examination Th e patien t complain s of severe forearm pain after traum a. Th e patien t will exh ibit con siderable swellin g an d ten dern ess over the forearm an d m ay h ave an obvious deform ity. A compreh ensive neurovascular exam ination should be perform ed an d compartm en ts of th e forearm sh ould be exam in ed carefully for sign s of in creased pressure. Radiographic Findings/Special Studies Stan dard an teroposterior an d lateral radiograph s of th e forearm are generally sufficient to m ake the diagnosis. Treatment Th is in jury usually occurs as a result of a h igh -en ergy m ech an ism and can cause sign ifican t soft tissue traum a (Fig. 15.33). In the pediatric population, both bon e forearm


609

class IID is perforation plus a lunotriqetral ligam ent tear. Last, class IIE is identical to class IID with th e addition of uln ocarpal arth ritis.

Mechanism of Injury Th e TFCC is susceptible to in jury, eith er from gen eral wrist overuse or from acute traum a. Th e specific m ech an ism is an extension or pronation force to an axially loaded wrist. Presentation and Physical Examination Patien ts with TFCC tears typically presen t with uln ar-sided wrist pain an d m ay complain of a clickin g sen sation in th eir wrist with certain m ovem en ts. Patien ts usually experien ce ten dern ess to palpation over th e fovea, wh ich is th e area between th e FCU an d ECU. Also, th e TFCC com pression test, wh ich in volves axial loadin g an d uln ar-deviatin g th e wrist, can often exacerbate pain .

Figure 15.33 Both bone forearm fracture. (Reprinted with per-

Radiographic Findings/Special Studies Plain radiograph s of th e wrist are usually un rem arkable. Th e gold stan dard for diagn osin g a TFCC tear was on ce wrist arth rography; however, MRI has proven m ore accurate and is considered the current study of choice. Wrist arth roscopy is another diagnostic m odality and is m ost useful for staging th ese lesions.

fractures can typically be treated with closed reduction and long arm casting. In adults, ORIF is required, generally through two separate incision s.

Differential Diagnosis Other causes of ulnar-sided wrist pain should be in cluded in the differential diagnosis for a TFCC tear, in cluding both ECU an d FCU ten don itis, uln ocarpal abutm en t, lun otriquetral in stability, uln ar styloid fracture, triquetrum fracture, and pisiform fracture.

mission from Bucholz RW, Heckman JD, Court-Brown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Tears of the TFCC In jury to th e TFCC is a com m on cause of uln ar-sided wrist pain . It is m ore likely to occur in patien ts with uln ar-positive variance.

Classification TFCC tears h ave been divided by Palm er in to two classes: traum atic (Class I) and degenerative (class II). Class IAtears are central perforation s of the articular disc. Class IBlesion s are ulnar-sided avulsion s that m ay or m ay not be associated with an uln ar styloid fracture. Th ese lesion s can destabilize the DRUJ. Class IC lesion s are distal avulsions of eith er the uln olun ate or uln otriquetral ligam en ts. Class ID lesion s involve radial-sided avulsions of either the dorsal or volar radiocarpal ligam en ts. Class II lesion s are degen erative an d are often th e result of uln ocarpal abutm ent syndrom e—excessive loadin g of th e uln ocarpal join t secon dary to positive uln ar varian ce. Class IIA lesions involve TFCC thinnin g, while class IIB involves thinnin g plus lunate an d/or ulnar ch on drom alacia. Class IIC is the addition of perforation to th e TFCC while

Treatment Alth ough certain types of TFCC tears m ay require surgical treatm ent, all TFCC tears warrant an initial trial of conservative therapy, which includes splinting, anti-inflam m atory m edication, and activity m odification for 6 weeks. On ly if sym ptom s persist sh ould arthroscopic or open surgery be con sidered. Class IA tears involve a relatively avascular zone and, th erefore, can n ot be repaired. In stead, arth roscopic debridem en t is th e treatm en t of ch oice. Class IB lesion s can destabilize th e DRUJ. Sin ce th ey occur in th e m ore vascular periph ery of th e articular disc, th ey are am en able to repair. Associated uln ar styloid fractures sh ould un dergo ORIF or closed reduction an d pin n in g. Class IC lesion s often require open repair. For class ID lesion s, direct repair (eith er open or arth roscopic) is advocated. Class IIA through IID can be m an aged with ulnar shorten in g, eith er at th e h ead (wafer procedure) or diaphysis. Th e goal is to m ake th e uln ar varian ce n egative. Class IIE lesions should be m anaged with either a Suave–Kapandji (DRUJ arthrodesis with uln ar neck resection) or Darrach procedure (distal ulna resection ).

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Carpal Instability Carpal in stability is a com m on ly en coun tered problem in hand surgery; however, it rem ains difficult to both diagn ose an d treat.

Classification Although m any system s pervade the literature, th e Mayo clinic classification system appears the m ost widely used. It divides carpal in stability in to four m ajor categories: carpal in stability dissociative (CID), carpal in stability n on dissociative (CIND), com plex in stabilities (dissociative and nondissociative), an d longitudinal or axial loading in stabilities. CID in volves disruption of intrinsic in terosseous ligam en ts of th e proxim al carpal row, in con trast to n on dissociative instability, which results from disruption of the extrinsic radiocarpal ligam en ts with in tact in trin sic ligam en ts. With in th e CID category are two importan t subgroups of in stability: dorsal in tercalated segm en t in stability (DISI) an d volar in tercalated segm en t in stability (VISI). Th e DISI deform ity, wh ich describes a palm ar-flexed scaph oid in com bin ation with a dorsiflexed lun ate–triquetram , is a result from eith er a scaph olun ate ligam en t disruption or un stable scaph oid fracture. Th e VISI deform ity, wh ich describes a palm ar-flexed scaph oid –lun ate in com bin ation with a dorsiflexed triquetram , usually results from lun otriquetral ligam en t disruption . Th e reason for th ese deform ities relates to th e biom ech an ics of th e wrist, wh ich are such that th e scaphoid gen erally wan ts to assum e a palm arflexed position while th e triquetrum wants to extend dorsally. When the lun ate loses its teth er to th e scaph oid from a SL ligam ent disruption or scaph oid fracture, th e lun ate m oves with th e triquetrum , assum in g a dorsiflexed position . Con versely, wh en th e lun ate loses its teth er to the triquetram from a LT ligam ent disruption, the lun ate m oves with th e scaph oid, assum in g a volar-flexed position . In DISI, PA radiograph s of th e wrist m ay dem on strate the Terry-Thomas sign, wh ich is SL widen in g greater th an 3 m m , and/ or the cortical ring sign, wh ich represen ts th e appearan ce of tubercle of th e scaph oid wh en palm ar-flexed (Fig. 15.34). In VISI, PA radiographs of the wrist m ay show widen in g of th e LT in terval. Lateral radiograph s of th e wrist will sh ow SL an gle greater th an 60 degrees in DISI or less than 30 degrees in VISI. The second category is CIND, which involves disruption of th e extrinsic radiocarpal ligam ents with intact intrinsic ligam ents and results in instability at the radiocarpal joint an d m idcarpal rows. Th is category is furth er subdivided in to three types: radiocarpal instability, m idcarpal in stability, an d uln ar tran slation . In radiocarpal in stability, disruption of either the dorsal or volar radiocarpal ligam en ts results in carpal drift. Midcarpal in stability, th e secon d subtype, in volves in stability between th e proxim al an d distal carpal row. A capitolunate angle of greater than 15 degrees or less th an 0 degrees on a true lateral radiograph is ch ar-

Figure 15.34 The Terry-Thomas sign for SL ligament disruption.


acteristic. The third subtype, ulnar translation, occurs after global ligam entous in jury to the radiocarpal joint. It describes uln ar m igration of the lunate relative to its norm al position in th e lun ate facet of th e distal radius. Radiograph ically, when less than 50% of the lunate rem ains in contact with th e distal radius, th e diagn osis of uln ar tran slation can be m ade. Ulnar translocation is tradition ally seen in patien ts with in flam m atory arth ropathy such as RA. Th e th ird category of carpal in stability is complex in stabilities, kn own as carpal instability combined (CIC). CIC involves disruption of ligam en ts between and with in the carpal rows. It is helpful to divide the perilun ate region into two arcs: the greater and lesser arcs. The greater arc con sists of the bony structures surrounding the lunate, including the scaph oid, trapezium , capitate, ham ate, and triquetrum . An example of a greater arc injury is the transscaphoid perilunate dislocation. The lesser arc is the ligam entous region surrounding the lunate. In juries to the lesser arc are less com m on th an those to the greater. An exam ple of a lesser arc in jury is a pure lun ate dislocation , wh ich is usually volar. Accordin g to Mayfield, th ere are four stages of perilunar instability proceeding from radial to uln ar around th e lun ate (Fig. 15.35). Stage I in volves disruption of th e scaph olun ate join t, whereas stage II violates both th e scaph olun ate an d capitolun ate articulation s. In stage III th e scaph olun ate, capitolunate, and lunotriquetral ligam ents are disrupted, and the result is a perilunate dislocation. Finally, in stage IV, all the ligam ents surroun ding the lunate are disrupted and the lunate dislocates volarly. Th e fourth category of carpal in stability is lon gitudin al or axial loadin g in stabilities. Th ese in juries are essen tially fracture-dislocations in which the attached MCs travel with the involved carpal bon e. They are caused alm ost exclusively by h igh -en ergy traum a to the carpus. They are further


III

611

II I IV

Figure 15.36 The scaphoid shift test. (Reprinted with permission

from Bucholz RW, Heckman JD, Court-Brown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Figure 15.35 The Mayfield stages of perilunar instability.


subdivided in to axial uln ar, axial radial, and com bin ed on the basis of the location of the injury.

Mechanism of Injury Mechanism s of injury range from a fall onto an outstretched h an d to a h igh -en ergy axial load to the wrist, as m ay occur during a m otor vehicle accident. Presentation Th e patien t m ay presen t with vague symptom s of wrist pain anywh ere in the carpal region depen ding on where the disruption h as occurred. They m ay also report a clunking sen sation with certain m ovem en ts of the wrist. Physical Examination Physical exam in ation for carpal in stability in clude th e scaphoid shift an d lunatotriquetral shear tests. Th e scaph oid sh ift test was design ed to evaluate th e com petency of the scapholunate ligam ent (Fig. 15.36). Durin g th is test, th e exam in er ran ges th e wrist from uln ar to radial deviation wh ile m ain tain in g con stan t pressure on th e scaph oid tubercle. Un der n orm al con dition s, th e scaph oid sh ould palm ar-flex; h owever, if th e scaph olun ate ligam en t is disrupted, the direct pressure on the scaph oid tubercle can subluxate the scaph oid, causin g the patient considerable

pain . A clun kin g sen sation m ay also be n oted as th e scaph oid proxim al pole subluxes dorsally with respect to th e radius. Th e lun atotriquetral sh ear test is used to evaluate lunatotriquetral instability. Th e thum b and index finger of on e of th e exam in er’s h an ds are used to stabilize th e lun ate and the oth er, to stabilize th e triquetrum . Sh ear forces are introduced across the joint. An increase in translation versus the contralateral side indicates path ology at the lun atotriquetral interval.

Radiographic Findings/Special Studies Standard radiographic evaluation for carpal instability includes PA, lateral, an d oblique views of th e h an d. Additional views th at are m ore specific for carpal instability include clenched-fist an teroposterior (accen tuates SL in terval widen in g), scaphoid view, an d flexion-extension lateral views (for dynam ic instability). On the PA view, three sm ooth curved lin es th at run across th e proxim al an d distal cortices of the proxim al carpal row and proxim al cortices of the capitate and ham ate, known as Gilula lines, can be drawn (Fig. 15.37). Any step-off in these lines indicates possible ligam entous disruption. In addition, the SL interval can be m easured, with a gap greater th an 3 m m in dicatin g disruption of th e scaph olun ate ligam en t (Terry-Th om as sign ). O n th e lateral, angles that sh ould be appreciated include radiolun ate (RL, n orm al < 15 degrees), capitolunate (CL, norm al 0 –15 degrees), and scapholun ate (SL, n orm al < 60 degrees). Arthrogram s are still very useful for detectin g

612


A

B Figure 15.37 (A, B) Gilula lines. (Reprinted with permission from Bucholz RW, Heckman JD, Court-

Brown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

ligam en t tears in th e carpus, but th e improved resolution of MRI h as ren dered it th e study of ch oice for detectin g th ese in juries.

Treatment Treatm en t for SL in stability with DISI deform ity is varied an d depen ds on th e recon structability of th e SL ligam en t. For acute SLligam en t tears treated with in th e first 6 m on th s, m any advocate open reduction an d prim ary ligam en t repair. Th e repair m ay be augm en ted by a Blatt dorsal capsulodesis. If th e ligam en t is n ot repairable but th e in stability is reducible, recon struction of th e ligam en t with ten don or bon e–ligam ent –bon e autograft or capsulodesis is recom m en ded. If th e in stability is n ot reducible, a scaph o – trapezial–trapezoidal (STT) or scaph ocapitate (SC) fusion m ay be in dicated. Wh en ch ron ic in stability is presen t, a pattern of arth ritis kn own as scapholunate advanced collapse (SLAC) can result. Th is pattern is discussed in detail in th e arth ritis portion of th e ch apter. Th e secon d subgroup of CID is th e VISI deform ity, in wh ich th e lun ate assum es a palm ar-flexed position wh ile th e triquetrum rem ain s in exten sion . Acute in stability can be treated with pin fixation while fusion of th e LTin terval is n eed for chron ic instability. For CIND with m idcarpal in stability, n on operative m an agem en t with im m obilization sh ould be attempted in itially. If th at treatm en t fails, a m idcarpal fusion m ay be in dicated. Treatm en t for CIND with uln ar tran slation in cludes im m ediate open repair, reduction, an d pin fixation. CIC in juries are typically treated with O RIF, with focus on restorin g th e n orm al SL gap. A prolon ged period of castin g (8 –12 weeks) typically follows. Last, for lon gitudin al or axial loadin g in stabilities, O RIF is th e m ain stay of treatm en t.

SOFT TISSUE INJURIES Skin and Nail Trauma Traum a to the skin and nail region is extrem ely com m on , especially in ch ildren an d youn g adults. Most in juries are sim ple laceration s an d generally have a good prognosis.

Classification Th ere is n o specific classification system for isolated skin an d nail traum a. Th ese injuries can be characterized by the exten t of n ail bed in volvem en t, location of th e in jury, an d the type of laceration (linear, stellate, etc.). Presentation and Physical Examination Patients usually present with th e injured region wrapped. Because each in jury to th e skin an d/ or n ail is different, there is no unifying presentation . The patient should be exam in ed closely. Much in form ation regardin g associated injuries can be obtained by simply inspecting the hand. A subungual hem atom a often indicates a nail bed disruption with an intact nail plate. Flexor and extensor tendon injuries can often be diagnosed by the posture of th e h and. If th e h an d is n ot in th e usual restin g cascade, a ten don injury m ust be excluded (Fig. 15.38). Vascular injuries can be diagn osed by th e color of th e distal digits. Followin g in spection , a full neurovascular exam ination sh ould be perform ed, and the function of all tendons sh ould be tested. Radiographic Findings/Special Studies Radiograph s are useful in diagn osin g associated fractures an d/or identifying foreign bodies. Orthogonal views are


Figure 15.38 Loss of the normal resting cascade suggests un-

derlying tendon injury. (Reprinted with permission from Doyle JR, Tornetta P, Einhorn TA. Orthopaedic Surgery Essentials: Hand and Wrist. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

necessary to avoid m issing any in juries. Typically, special studies are not in dicated or n ecessary.

Treatment On presentation, it is imperative that the patient’s tetan us status is up to date. If n ot, a booster shot should be given . Th e appropriate treatm en t of n ail traum a is depen den t on the size of the injury. If a subungual hem atom a occupies less than 25% of th e nail, then treatm ent consists of symptom atic care. If a subun gual h em atom a in volves 25% to 50% of th e n ail, th en a sm all perforation can be m ade in the nail to relieve the fluid pressure, wh ich decreases pain. If greater th an 50% of th e n ail is in volved, som e h an d surgeon s recom m en d rem ovin g th e n ail an d explorin g th e n ail bed, alth ough th is rem ain s con troversial. Laceration s can be repaired by usin g fin e absorbable sutures (6 –0 chrom ic), although skin glue can be used for simpler injuries. After the repair, th e rem oved n ail or another type of stent sh ould be replaced un der th e n ail fold to preven t it from scarrin g down on th e n ail bed. While woun ds sh ould be closely exam ined, th ey sh ould not be extensively explored in the em ergen cy departm en t settin g. Bleeding should be stopped by direct pressure, and on e sh ould avoid blin dly clampin g any bleedin g vessels, given the proxim ity of the digital nerves to the digital vessels. If evaluation indicates no injuries to th e deeper structures, the laceration should be copiously irrigated an d then loosely closed with simple 4 –0 or 5 –0 nylon sutures. In ch ildren , absorbable sutures, such as chrom ic gut, m ay be preferred to avoid th e n eed for rem ovin g th e sutures in th e office. An tibiotics sh ould be given depen din g on th e size an d contam ination of th e wound. If th ere is an amputation of th e distal part of th e fin ger, treatm en t is depen den t on location . Distal in juries can often be treated with isolated debridem en t an d composite grafting by using the amputated part. Even if this graft

A

B

613

C

Figure 15.39 The Atasoy–Kleinert V-Y advancement flap.

(Reprinted with permission from Moran SL, Cooney WP. Master Techniques in Orthopaedic Surgery: Soft Tissue Surgery. Philadelphia, PA: Lippincott Williams & Wilkins, 2009.)

fails, th e fin ger tip can frequen tly h eal by secon dary in ten tion in sm all wounds (< 1 cm ). If bon e is exposed, it can be debrided back proxim al to th e skin defect to allow for prim ary closure. Wh en th is is don e, it is importan t n ot to advance the n ail bed distally as this will lead to a hooked nail deformity. More sign ifican t soft tissue defects can be treated in a variety of ways. Skin grafts are used for areas with skin loss but adequate deep soft tissue coverage. Split th ickn ess skin grafts can cover large areas an d are prim arily used for the dorsal surface of the han d. Full-th ickness skin grafts are m ore cosm etic and are preferred for palmar defects. Wh en bon e is exposed, local advan cem en t flaps are ideal for obtaining coverage. Distal finger amputation s can often be treated by eith er a volar or lateral VYflaps (Fig. 15.39). For amputation s th rough th e tip of th e th um b, th e Moberg advancem ent flap is preferred (Fig. 15.40). This flap can cover defects up to 2.5 cm , but it risks a th um b IP flexion contracture. Th ese local flaps provide sensate soft tissue coverage for th e fin gertip in sm all cen tral defects. Larger defects require regional flaps. The cross-finger flap is useful for volar fin ger defects an d is based on the dorsal aspect of the m iddle phalanx (Fig. 15.41). The donor site requires skin graftin g. Th e thenar flap is in dicated for loss of skin an d pulp of th e lon g or rin g fin gers (Fig. 15.42). Th is flap can cause PIP join t con tractures but rem ain s useful in youn g patien ts. Other flaps, such as the neurovascular island flap and the first dorsal MC artery flap, are available for m ore proxim al coverage, but th ese are m ore tech n ically dem an din g.

Flexor Tendon Injuries Flexor tendon injuries are relatively com m on but can have a detrim en tal effect on h an d fun ction . Historically, th e out-

614


A,B

C

D

E

F

G

Figure 15.40 (A–G) The Moberg advancement flap. (Reprinted with permission from Moran SL, Cooney WP. Master Techniques in Orthopaedic Surgery: Soft Tissue Surgery. Philadelphia, PA: Lippincott Williams & Wilkins, 2009.)

com es from th is injury were extrem ely poor secondary to ten don adh esion s, but advan ces in basic scien ce, surgical tech n ique, an d postoperative reh abilitation h ave improved results.

Pathophysiology Ten don h ealin g occurs by a com bin ation of in trin sic an d extrin sic m ech an ism s. Th e in itial in flam m atory ph ase be-

gin s im m ediately after the injury when the defect is filled with blood clot an d in flam m atory cells. As th ese cells proliferate, they prom ote m igration of m ore fibroblasts in to th e repair site an d begin th e h ealin g process. Th e n ext stage is fibroblastic. At approxim ately 1 to 2 weeks from injury, th e fibroblasts begin secretin g collagen , a process th at con tinues for approxim ately 4 m ore weeks. At approxim ately 6 weeks, th e rem odelin g stage begin s an d th e fibroblasts

615


A

B Figure 15.41 (A, B) The cross-finger flap. (Reprinted with permission from Moran SL, Cooney WP.

Master Techniques in Orthopaedic Surgery: Soft Tissue Surgery. Philadelphia, PA: Lippincott Williams & Wilkins, 2009.)

begin to reorien t th em selves in lin e with th e ten don ; th e collagen fibrils realign with them . At 8 weeks, the repair gap is completely filled with collagen. As physiologic loadin g begin s, th e ten sile stren gth of th e repair in creases steadily.

Classification and Mechanism of Injury Flexor ten don in juries are classified by th e zon e (location ) of in jury (Fig. 15.43). Zon e I is distal to th e FDS in sertion and contains only on e tendon (FDP or FPL). In this zon e, th e ten don can be lacerated or avulsed from its in sertion . FDP avulsion s occur secon dary to forced extension of th e digit durin g m axim al con traction of th e ten don an d is referred to as a jersey finger (Fig. 15.44). This injury of-

ten occurs in ath letes an d is com m on ly m isdiagn osed as a sprained or jam m ed finger. Leddy classified these injuries into three types, and the prognosis is based on the am ount of ten don retraction , th e rem ain in g ten don blood supply, and the tim ing of repair. Zon e II is th e region from th e MC n eck (A1 pulley) to th e m iddle of the m iddle phalanx (FDS insertion) and contains

Zone I

Zone II

Zone TI

Zone TII

Zone III Zone IV

Zone TIII Zone V Figure 15.42 The thenar flap. (Reprinted with permission from

Strickland JW, Graham TJ. Master Techniques in Orthopaedic Surgery: The Hand. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)

Figure 15.43 The flexor zones of the hand. (Reprinted with permission from Doyle JR, Tornetta P, Einhorn TA. Orthopaedic Surgery Essentials: Hand and Wrist. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

616


cascade is usually disrupted (Fig. 15.45). Th e FDS an d FDP ten don s of each digit sh ould be m an ually tested in isolation. It m ust be rem em bered that one-third of all norm al individuals are m issing th e FDS to th eir sm all finger. Also, it is important to rem em ber that the site of skin laceration does n ot always correlate with th e zon e of ten don laceration because the latter is dependent on the position of th e fingers at the tim e of in jury. O f course, the presence or absen ce of concom itant n erve and vessel injuries sh ould also be determ in ed.

Figure 15.44 Avulsion of the flexor digitorum profundus of the

ring finger. (Reprinted with permission from Strickland JW, Graham TJ. Master Techniques in Orthopaedic Surgery: The Hand. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)

both th e FDS an d FDP ten don s. Th is zon e is oth erwise known as no man’s land because it h as poor results with direct repair secon dary to adh esion form ation . Zon e III is in the palm where the lum brical m uscles originate and is defin ed by th e area between th e distal edge of th e TCL an d th e distal palm ar crease. Isolated in juries in th is zon e have a relatively good progn osis but are often complicated by associated nerve and/or vessel injury. Zon e IV is the carpal tunn el. The TCL can protect tendon injuries in th is area, but wh en th ey occur, th ey are usually associated with nerve (m edian an d/ or ulnar nerve) in juries. Zone V is in the forearm from the m usculotendinous junction of the flexors to the proxim al edge of the TCL. Concom itan t nerve or vessel in juries in th is zon e result in th e classic “spagh etti wrist.’’ O verall, th e progn osis for ten don recon struction is best in th is zon e.

Presentation and Physical Examination Flexor ten don s are usually in jured after a sh arp laceration or sign ifican t blun t traum a. Patien ts presen t with th e in ability to flex th e affected fin ger, an d th e n orm al fin ger

Radiographic Findings Radiograph s are un n ecessary in diagn osin g flexor ten don ruptures. However, th ey provide som e utility if there is concern regarding con com itant fractures. Special Studies Flexor ten don rupture can usually be diagn osed on th e basis of h istory an d physical exam ination. If the diagnosis is un clear, MRI or ultrasoun d can be used to con firm th e diagnosis. These m odalities also help to identify partial flexor ten don ruptures. Differential Diagnosis Th e differen tial of flexor ten don in juries in clude n erve in juries th at cause m uscle paralysis an d un derlyin g n eurological conditions, such as polio or spinal m uscular atrophy. A h istory of traum a gen erally distin guish es flexor ten don injuries from these other conditions. Treatment Complete flexor ten don ruptures should be repaired surgically. Partial tendon lacerations are difficult to diagnose, but laceration s greater th an 60% sh ould be repaired to preven t triggering or subsequent rupture. In flexor ten don repair, several factors affect outcom e. First, prim ary ten don repair sh ould be perform ed early. No differen ce in results h as been foun d between em ergen t an d delayed early repairs, but worse outcom es m ay occur if

A

B Figure 15.45 Note the loss of the normal cascade (A) and inability to flex the distal interphalangeal joint (B). (Reprinted with permission from Doyle JR, Tornetta P, Einhorn TA. Orthopaedic Surgery Essentials: Hand and Wrist. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)


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Figure 15.46 Recommended skin incisions for extension of traumatic hand wounds. Dotted lines represent the safe extensions of these wounds. (Reprinted with permission from Doyle JR, Tornetta P, Einhorn TA. Orthopaedic Surgery Essentials: Hand and Wrist. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

surgery is done after several weeks due to tendon retraction. If diagn osis or treatm en t is delayed, th e patien t m ay require a two-stage recon struction , usin g silicon rods. Th e rod is used to create a syn ovial sh eath for even tual placem en t of ten don graft. In addition to early tim in g, th e repair m ust be stron g en ough to allow early m otion . Many studies h ave exam ined different suture techn iques. While several h ave been sh own to be effective, including th ose advocated by Strickland (Fig. 15.46) and Tajim a (Fig. 15.47), the general conclusion is th at strength is directly proportion al to the num ber suture stran ds crossin g th e repair site. Curren tly, m ost surgeons recom m end at least four core stands of 3 –0 n on absorbable suture supplem ented with a run ning epitenon stitch (usually 5 –0 nylon ). Ideally, core sutures are placed dorsally to provide addition al stren gth . For zon e I in juries, treatm en t in volves attach m en t of the proxim al stump to th e bone by using suture anchors or pull-out sutures over a button (Fig. 15.48). Ten don advancem en t greater than 1 cm m ust be avoided to preven t th e quadregia effect, which is fun ctional shortening of on e of th e profun dus ten don s. Prim ary en d-to-en d repair is the treatm ent of ch oice for zone I tendon laceration s, but occasion ally th e quality of th e distal stum p is so poor th at these laceration s are treated as avulsions. Postoperative rehabilitation is essential to achieve a good result. Early m otion gives repaired tendons greater

ten sile stren gth , excursion , an d fun ction th an seen with im m obilization . Th e m ost com m on protocols are active exten sion with rubber ban d flexion (m odified Klein ert), controlled passive m otion (m odified Duran) (Fig. 15.49), an d con trolled active m otion . Un like adults, ch ildren are im m obilized for 4 weeks because th ey can n ot comply with th ese protocols, an d they are less likely to becom e as stiff.

Extensor Tendon Injuries Alth ough exten sor ten don in juries are discussed less frequen tly th an flexor ten don in juries, th ey can be quite com plex with sim ilar detrim en tal effects on h an d fun ction .

Classification Sim ilar to flexor tendon injuries, zones can be used to define the location of exten sor tendon injuries. Nine zones h ave been defin ed an atom ically, with th e odd zon es occurrin g over join ts an d th e even zon es occurrin g over bon es (Fig. 15.50). Zon e I is over the DIP join t and involves th e disruption of th e term in al ten don , wh ich leads to DIP flexion . These in juries are com m on ly referred to as mallet fingers (Fig. 15.51). Zone II in juries occur over the m iddle ph alan x. Zon e III in juries are directly over th e PIP join t an d involve disruption of the cen tral slip of the extensor m ech anism . Th e PIP joint goes into flexion , and chronic injuries

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A

B

C

D

E

F Figure 15.47 (A–F) Flexor tendon repair. (Reprinted with permission from Strickland JW, Graham TJ. Master Techniques in Orthopaedic Surgery: The Hand. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)

can develop a boutonniere deform ity ch aracterized by PIP flexion an d DIP hyperexten sion secondary to volar m igration of th e lateral ban ds (Fig. 15.52). Zon e V in juries occur over th e MP join t an d are extrem ely com m on . Th ese in juries usually occur durin g altercation s wh en a fist im pacts the tooth of an opponen t (“fight bites’’).

Presentation/Mechanism of Injury Extensor tendon injuries usually occur via traum a. Com m on m ech an ism s are altercation s, sh arp laceration s, or

“jam m in g’’ of a fin ger. Presen tation an d deform ity is depen den t on th e location of th e exten sor ten don disruption (Fig. 15.53).

Physical Examination As with the flexor tendons, extensor tendon injury is relatively straightforward to diagn ose. Inspection will often reveal exten sor lag, an d exam in ation reveals th e in ability to actively exten d th e fin ger. Each fin ger sh ould be tested in isolation with the adjacent fingers flexed at th e MP joints.


A

619

B Figure 15.48 (A, B) Repair of the flexor digitorum profundus tendon. (Reprinted with permission from Strickland JW, Graham TJ. Master Techniques in Orthopaedic Surgery: The Hand. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)

Th is position elim in ates th e pull of th e jun cturae ten dinae (fibrous connections between th e tendons), which can m ask isolated extensor tendon disruption . Also, active exten sor stren gth sh ould be tested at each join t or zon e. Th e Elson test is a specific test for diagn osin g an acute bouton n iere deform ity in a patien t with a cen tral slip in jury (Fig. 15.54). It is perform ed with th e fin ger flexed 90 degrees over a table at th e PIP join t. In th is position , th e patient attempts to extend the PIP joint. With an intact central slip, there sh ould be extension pressure through th e m iddle ph alan x wh ile th e distal ph alan x is flail. With a disrupted cen tral slip, the m iddle phalanx is lax, whereas the distal ph alan x is rigid th rough th e DIP join t.

Again , it is important to rem em ber th at th e site of skin laceration does n ot always correlate with th e zon e of ten don laceration because it is depen den t on th e position of fin gers at th e tim e of in jury. Of course, on e sh ould also evaluate th e patien t for con com itan t n erve or vessel in juries.

Radiographic Findings Radiograph s are m an datory durin g evaluation to rule out fractures and foreign bodies such as teeth. Special Studies It is rare th at advan ced im agin g is n ecessary in th e diagn osis or treatm en t of exten sor ten don in juries.

B A

Figure 15.49 (A–C) Post flexor tendon repair motion protocol.

C

(Reprinted with permission from Strickland JW, Graham TJ. Master Techniques in Orthopaedic Surgery: The Hand. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)

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Figure 15.50 Zones of extensor tendon injury. (Reprinted with

permission from Doyle JR, Botte MJ. Surgical Anatomy of the Hand and Upper Extremity. Philadelphia, PA: Lippincott Williams & Wilkins, 2003.)

Treatment In m an agin g th ese in juries, several gen eral prin ciples sh ould be kept in m ind. First, open injuries sh ould gen erally be treated in an open m an n er with surgery, wh ereas closed injuries sh ould be initially treated closed with splin t-

ing. Surgical repair should be perform ed with a nonabsorbable m aterial and a core suture. Partial open ten don injuries sh ould be repaired if greater than 50% of the tendon width is lacerated. Zon e I in juries can be treated with exten sion splinting for 6 weeks with a Stack splint and then subsequen t n igh ttim e splin tin g for an addition al 6 weeks (Fig. 15.55). Splin tin g is th e prim ary treatm en t also in fin gers presen ting up to 6 m onths after injury. Untreated zon e I in juries will lead to a swan -n eck deform ity with DIP flexion an d PIP hyperexten sion secon dary to dorsal m igration of th e lateral ban ds. This deform ity requires significant surgical recon struction to be corrected. Mallet fin gers can also occur with an avulsion fracture of the distal phalanx. Treatm en t rem ains the sam e unless there is DIP subluxation or the fracture fragm ent is greater th an 50% of the articular surface. Zon e II injuries require suture repair if greater than 50% of th e ten don is disrupted. Again , n on absorbable suture is preferred an d core sutures sh ould be used. Sim ilar to m allet fin gers, zon e III in juries are usually treated nonoperatively with extension splin ting of the PIP join t for 6 weeks. Patien t com plian ce is im portan t because recon struction of ch ron ic bouton n iere deform ities (i.e., th e Fowler procedure) is difficult. Zon es IV through IX in juries all require prim ary repair. In zon e V in juries, urgen t surgical irrigation an d debridem en t is necessary if the join t capsule h as been violated. A com m only associated injury is sagittal band rupture. Most often, the radial sagittal band of th e lon g finger is ruptured, which leads to ulnar subluxation of th e exten sor m ech an ism . Closed injuries can be treated with extension splin tin g for 4 to 6 weeks, but open injuries sh ould be repaired.

Nerve Injury Nerve in juries from laceration s or crush in juries to th e h an d are relatively com m on .

Pathophysiology/Classification Th e classification was origin ally described by Seddon an d subsequently m odified by Sunderland (Table 15.2). Type I (neuropraxia) is a conduction block with axon continuity preserved. Type II (axon otom esis) in volves axon al dam age but th e en don eurium is preserved. Type III (axon otom esis) describes axon al dam age but th e perin eurium is preserved. Type IV (axon otom esis) in volves axon al dam age with on ly the epineurium intact. Fin ally, type V is a complete nerve transection. Figure 15.51 Mallet finger. (Reprinted with permission from Doyle JR, Tornetta P, Einhorn TA. Orthopaedic Surgery Essentials: Hand and Wrist. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Presentation/Physical Examination Presen tation varies an d is depen den t on th e specific n erve involved. Physical exam ination will yield deficits in th e distribution of the n erve involved.


621

A

Figure 15.52 (A, B) Chronic boutonniere

deformity. EDC, extensor digitorum communis; MP; PIP, proximal interphalangeal; DIP, distal interphalangeal. (Reprinted with permission from Strickland JW, Graham TJ. Master Techniques in Orthopaedic Surgery: The Hand. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)

B

TABLE 15.2

COMPARISON OF SUNDERLAND AND SEDDON CLASSIFICATION OF NERVE INJURIES Author

Descriptive Term

Nature of Injury/Neuropathology

Sunderland Seddon Seddon Sunderland

First-degree injury Neurapraxia Second-degree injury (axonotmesis)

Demyelinating injury with a temporary conduction block

Sunderland Seddon

Third-degree injury (neurotmesis)

Sunderland

Fourth-degree injury

Sunderland

Fifth-degree injury

Distal degeneration of the injured axon but with almost always complete regeneration due to intact endoneurium Sunderland third-degree injury is less severe than the neurotmesis category of Seddon since the perineurial layer is intact. Regeneration occurs but is incomplete due to endoneurial scarring and loss of end-organ specificity within the fascicle Axon, endoneurium, and perineurium are disrupted with extensive scarring that blocks axonal regeneration and often results in a neuroma-in-continuity Severed nerve trunk without possibility of spontaneous regeneration

(Reprinted with permission from Doyle JR, Tornetta P, Einhorn TA. Orthopaedic Surgery Essentials: Hand and Wrist. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

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to prevent neurom a form ation . Prim ary nerve repair is favored, but nerve grafts should be considered if a tensionfree nerve repair cannot be achieved. Com m on nerve grafts include the sural nerve, the anterior branch of the m edial antebrachial cutaneous nerve, the lateral antebrachial cutan eous n erve, an d th e term in al bran ch of th e posterior in terosseous n erve. Recen tly, autogen ous vein con duits an d synth etic n erve grafts h ave been used with som e success. After appropriate align m en t of th e n erve, epin eurial repair is currently preferred because grouped fasicular repair h as n ot been sh own to be superior (Fig. 15.56). Suture size is depen den t on th e size of th e n erve bein g repaired. In ch ildren , fibrin glue h as been used successfully in place of a suture. After nerve repair, occupational therapy is importan t to provide m otor an d sen sory reeducation .

Replantation Advances in m icrosurgical techn iques and instrum entation in the late 1950s and the early 1960s led to the ability to replan t detach ed lim bs. Malt an d McKh an n perform ed th e first successful arm replan tation in Boston in 1962, an d Kom atsu and Tam ai perform ed the first successful digital replan tation in 1968. Today, th e survival rates for digital replan ts are greater th an 90% if perform ed for appropriate indications.

Figure 15.53 Deformities secondary to extensor mechanism injury. (Reprinted with permission from Doyle JR, Botte MJ. Surgical Anatomy of the Hand and Upper Extremity. Philadelphia, PA: Lippincott Williams & Wilkins, 2003.)

Radiographic Findings Radiograph s are un n ecessary in n erve in juries un less associated bon e injury is suspected. Differential Diagnosis Th e differen tial diagn osis in cludes ten don disruption s th at m ay m im ic n erve in juries. Th ese two diagn oses can be distin guish ed by th e use of th e ten odesis effect, wh ich sh ould be presen t on ly in patien ts with n erve in juries but absen t if there is a ten don injury. The tenodesis effect refers to spon tan eous flexion of th e digits wh en th e wrist is passively exten ded an d im plies con tin uity of th e extrin sic ten don s. Also, underlying neurological con ditions, such as polio or spin al m uscular atrophy, m ust be excluded. Treatment When a lacerated n erve is foun d, m icrosurgical repair sh ould be perform ed to facilitate nerve regen eration an d

Classification No specific classification sch em e exists. In juries are described by location of amputation and the quality of soft tissue. Mechanism of Injury Th ere are m any differen t m ech an ism s th at cause upper extrem ity amputations. Com m on causes include lawn m owers, sn owblowers, in dustrial m ach in es, an d m otor veh icle collisions. Physical Examination Th e m ost importan t aspect of th e physical exam in ation is inspection of the amputated site and residual part. It is vital to assess th e quality of th e soft tissues an d to determ in e wh eth er replan tation h as a ch an ce to be successful. Most often , th is is depen den t on wh eth er th e am putation was a sh arp or a crush injury. Radiographic Findings Radiograph s of both th e amputated part an d th e residual lim b are necessary to assess th e bone stock and to determ ine the best m ode of bone fixation . Treatment Wh en ever a part of th e h an d or upper extrem ity is amputated, th e part sh ould be wrapped in salin e-soaked gauze


Figure 15.54 Elson test for detection of boutonierre

deformity. (Reprinted with permission from Doyle JR, Botte MJ. Surgical Anatomy of the Hand and Upper Extremity. Philadelphia, PA: Lippincott Williams & Wilkins, 2003.)

Figure 15.55 Splints used to treat mallet fin-

ger deformity. (Reprinted with permission from Doyle JR, Tornetta P, Einhorn TA. Orthopaedic Surgery Essentials: Hand and Wrist. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

623

624


Figure 15.56 Techniques of peripheral nerve repair. (Reprinted

with permission from Doyle JR, Tornetta P, and Einhorn TA: Orthopaedic Surgery Essentials: Hand and Wrist. Philadelphia: Lippincott Williams & Wilkins, 2006.)

an d placed in side a plastic bag or sterile con tain er. Th is sh ould subsequently be placed on ice for transport to th e defin itive treatm en t cen ter with th e patien t. Upon arrival, the patient should be given antibiotics and tetanus prophy-

laxis. The amputation site and part should then be evaluated to determ ine whether replantation is possible. Th e curren tly accepted in dication s for replan tation are any thum b amputation, m ultiple digit amputations, any amputation in a child, and partial hand amputation s th rough th e palm , wrist, or forearm (Table 15.3). Th e duration of isch em ia tim e is also extrem ely im portan t. Warm ischem ia tim e of m ore than 12 hours for digital amputation or m ore than 6 hours for amputations proxim al to th e carpus leads to poor outcom es Coolin g of parts gives an addition al isch em ia tim e of 24 h ours for digits an d 12 h ours for m ajor lim bs. Acceptable ischem ia tim e is less for m ore proxim al am putation because m uscle can tolerate less ischem ia than tendon. The type of injury is also extrem ely importan t. Sharp amputation s do significantly better than crush or deglovin g in juries. Fin ally, patien t factors play a role in decidin g wh eth er replan tation sh ould be attempted. Youn ger patien ts h ave better outcom es. Preexistin g con ditions such as diabetes, peripheral vascular disease, hypercoagulopathy, n icotin e depen den ce, an d severe psych iatric con dition s decrease success rates. Patien ts m ust also be able and willing to comply with the long postoperative rehabilitation program . Wh en replan tation is attempted, a stan dard operative sequen ce is used. After identification of structures and debridem en t of n ecrotic tissues, th e bon e is sh orten ed an d fixed to allow decreased tension on the neurovascular structures. Next, the extensor tendons, th e flexor ten don s, the arteries, the nerves, and the veins are repaired in that order. All repairs m ust be perform ed usin g careful m icrovascular tech n ique. In m ultiple digital amputation s, repair of th e sam e an atom ic structure in each digit improves operative efficien cy. In m ajor lim b replan tation , arterial sh un tin g is th e first step to lim it isch em ic tim e. Postoperatively, patients m ust be m onitored closely to prevent unn ecessary failure. Dressings and protective splin ts should be applied carefully to avoid compression. Th e extrem ity sh ould be elevated h igh en ough to preven t

TABLE 15.3

INDICATIONS AND CONTRAINDICATIONS FOR FINGER REPLANTATION Indications Amputation of the thumb at any level Amputation of multiple digits Any amputation in children Single-digit injury in zone I

Controversial Indications Single-digit amputation at a level proximal to the insertion of the flexor digitorum superficialis tendon Ring avulsion injuries Severe contamination

Contraindications Amputated parts that are severely crushed or damaged Multiple-level amputations Significant associated trauma and/or medical conditions (Reprinted with permission from Moran SL, Cooney WP. Master Techniques in Orthopaedic Surgery: Soft Tissue Surgery. Philadelphia, PA: Lippincott Williams & Wilkins, 2009.)

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A

B

C D

Figure 15.57 (A–E) Case example of finger replantation.

E

(Reprinted with permission from Moran SL, Cooney WP. Master Techniques in Orthopaedic Surgery: Soft Tissue Surgery. Philadelphia, PA: Lippincott Williams & Wilkins, 2009.)

ven ous pooling but low enough to allow arterial inflow. Th e patien ts sh ould avoid any vascocon strictors such as nicotine, caffeine, an d chocolate, and the room should be kept warm and quiet. Anticoagulation is dependent on the preferen ce of th e surgeon , but m ultiple agen ts such as aspirin , h eparin , dextran , an d dipyridam ole h ave been used. Replants should be checked h ourly for adequate perfusion. Leech es are occasion ally used to relieve venous congestion if venous outflow is inadequate. As stated earlier, the survival rates for replantation of clean amputations in appropriate patients is 90%. However, fun ction al results vary sign ifican tly (Fig. 15.57). Stiffness, cold sensitivity, and ch ron ic pain can be sign ifican t problem s. Return to th e operatin g room is often n ecessary. In sum m ary, replan tation is a powerful but tech nically dem andin g tool, which is associated with a high

complication rate; correct patient selection is therefore imperative.

NONTRAUMATIC INJURIES TO THE HAND AND WRIST Compressive Neuropathies Compressive n europathies result from m echanical com pression th at causes local n erve isch em ia an d dysfun ction . Traction is also thought to play a role in this disease process. Wh en diagn osed an d released early, n erve recovery is predictably good. However, after a long-standing injury, decom pression m ay on ly h alt th e progression of disease rath er th an reverse th e sym ptom s.

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The gen eral assessm ent of a patien t in wh om a com pressive n europathy is suspected sh ould in volve a careful history and physical exam in ation. The h istory should evaluate predisposin g factors such as system ic or in flam m atory con dition s in cludin g diabetes, hyperthyroidism , RA, an d infection. Also, the history should draw out con ditions that alter fluid balance, such as pregn ancy and hem odialysis. On exam ination, on e should focus on finding objective sign s of m otor or sen sory ch an ges an d tryin g to isolate the exact level at which the compression is present. Motor strength is graded on the standard scale of 1 to 5. Sen sory exam ination consists of both thresh old (ligh t touch ) an d innervation den sity (2-point discrim ination ) testing. Sem m es–Wein stein testin g with m onofilam ents is h elpful in diagnosin g early sen sory change. The concept of a double crush ph en om en on , with en trapm en t at two levels, m ust always be considered because both sites of compression m ay require release.

Carpal Tunnel Syndrome CTS is th e m ost com m on upper extrem ity compressive n europathy.

Pathophysiology CTS is compression of th e m edian n erve as it passes un dern eath th e TCL in th e wrist (Fig. 15.58). Poten tial causes in clude an atom ic abn orm alities (such as proxim al lum brical m uscles), fluid im balances (pregnan cy, hem odialysis), traum a (h em atom a, distal radius fractures), an d position al factors. Presentation/Mechanism of Injury CTS usually presen ts with decreased sen sation over th e palm ar aspect of radial th ree fin gers an d th e radial side of th e ring fin ger. The num bn ess is typically worse at night. As the syndrom e progresses, patients complain of weakness an d pain th at can radiate in to th e volar forearm . If left un treated, CTS can lead to th en ar atrophy. Physical Examination Physical exam in ation in cludes Tin el test (tappin g over th e TCL, which elicits electric-like shocks th at radiate into the fin gers), Ph alen test (m an ual volar flexion of th e wrist, which reproduces the patient’s sym ptom s), an d th e carpal tun n el com pression test (reproduction of th e patien t’s symptom s from direct compression over the volar aspect of th e carpal tun n el) (Table 15.4). Each of th ese tests h as varying degrees of sen sitivity an d specificity, but com bined with a h istory an d electrom yography (EMG), a reliable diagn osis can usually be obtain ed. Special Studies EMG and n erve conduction studies (NCSs) are useful tests to h elp con firm th e diagn osis of CTS. Ch an ges con sisten t with a diagn osis of CTS in clude distal m otor latency greater

th an 4.0 m s or asym m etry of 1.0 m s between th e in volved and uninvolved hands. In addition, a distal sensory latency greater th an 3.5 m s or asym m etry of 0.5 m s between han ds is highly suggestive of CTS.

Treatment Once diagnosed, CTS can be treated nonoperatively or operatively. In itial treatm en t usually focuses on n igh ttim e wrist splin tin g in a n eutral position , oral an ti-in flam m atory m edications to decrease syn ovitis and edem a, and m anagem en t of underlying m edical problem s. Corticosteroid in jection s can be perform ed directly in to th e carpal tun n el. Although injection s provide transient relief to 80% of patients, only 22% of patients have con tinued symptom atic relief at 1 year. Alth ough relief m ay be on ly tran sien t, it is a good prognostic sign for surgical release. Surgical treatm en t can be don e eith er open or en doscopically. Although debate still exists over which is the optim al procedure, data con tin ue to sh ow m in im al differen ces between the two procedures. Endoscopic carpal tunnel release m ay result in less pillar pain and earlier return to work, but there is a slightly increased risk of in complete release. Success after either procedure results in improved pain an d decreased n um bn ess, wh ich is proportion al to th e am oun t of preoperative EMG dysfun ction .

Pronator Syndrome Pathophysiology Pron ator syn drom e in volves proxim al compression of the m edian nerve. Potential compression sites include a supracon dylar process of the hum erus with an associated ligam en t of Struthers, the lacertus fibrosis or bicipital aponeurosis, the pronator teres origin, and the origin of the FDS (Fig. 15.59). Presentation Th e prim ary presen tin g symptom s are n um bn ess in th e radial th ree fin gers an d th e radial side of th e rin g fin ger, as well as forearm pain. Pron ator syndrom e rarely presen ts with m otor weakn ess. Physical Examination Pron ator syn drom e is clin ically differen tiated from CTS by n um bn ess in th e palm ar cutan eous bran ch distribution, pain with resisted wrist flexion an d forearm pron ation , an d a n egative Phalen and carpal compression tests. Special Studies EMG is usually n ecessary to defin itively distin guish pron ator syn drom e from CTS, alth ough th e accuracy of th e study for this con dition can be variable. Differential Diagnosis Pron ator syn drom e m ust be differen tiated from th e m ore com m on CTS.


Plamaris longus

Common digital branches of median n. Sensory digital branches of ulnar n.

Superficial radial a. Flexor pollicis brevis

Hypothenar muscles Volar carpal ligament (roof of Tunnel of Guyon)

Abductor pollicis brevis Transverse carpal ligament Median n. Flexor carpi radialis Antebrachial fascia

Flexor carpi ulnaris

Palmaris longus Flexor digitorum superficialis Radial a.

Ulnar n. and a.

Ulnar a. Hook of hamate Transverse carpal ligament

Ulnar n. Volar carpal ligament (roof of Tunnel of Guyon)

Pisiform Pisohamate ligament

Flexor carpi ulnaris Triquetrum

Scaphoid

Lunate

Figure 15.58 The carpal and ulnar tunnels. (Adapted with permission from Hoppenfeld S, deBoer P. Surgical Exposures in Orthopaedics: The Anatomic Approach. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2003.)

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TABLE 15.4

TESTS FOR CARPAL TUNNEL SYNDROME (CTS) Interpretation of Positive Result

Test

How to Perform

Condition Tested

Phalen test

Elbows on table, forearms vertical, wrists flexed Lightly tap along median nerve from proximal to distal Direct compression of median nerve at carpal tunnel Patient marks site of pain or altered sensation on outlined hand diagram Hand volume measured by displacement, repeat after 7-minute stress test and a rest of 10 minutes Wick or infusion catheter placed in carpal tunnel

Paresthesia in response to position Site of nerve lesion

Numbness or tingling on radial digits within 60 s “Electric” tingling response in fingers

Paresthesia in response to compression

Paresthesia within 30 s

Patient’s perception of symptoms

Markings on palmar side of radial digits, without markings in palm Hand volume increased by 10 mL or greater

Probable CTS (sens 0.96, spec 0.73, negative predictive value 0.91) Probable dynamic CTS

Hydrostatic compression is felt to be probable cause of CTS

Determine minimum separation of two distinct points when applied to palmar fingertip As mentioned earlier, with movement of the points

Innervation density of slow-adapting fibers

Resting pressure 25 mm Hg or more (variable and technique related) Failure to determine separation of at least 5 mm

Advanced nerve dysfunction

Vibrometer placed on palmar side of digit, amplitude set to 120 Hz, and increase to threshold of perception; compare median and ulnar bilaterally Monofilaments of increasing diameter touched to palmar side of digit until patient can determine which digit is touched Orthodromic stimulus and recording across wrist

Threshold of fast-adapting fibers

Failure to determine separation of at least 4 mm Asymmetry compared with contralateral hand or median to ulnar in ipsilateral hand

Threshold of slowly adapting fibers

Value greater than 2.83

Median nerve impairment (sens 0.83)

Latency, conduction of sensory fibers

Probable CTS

Orthodromic stimulus and recording across wrist

Latency, conduction velocity of motor fibers of median nerve

Needle electrodes placed in muscle

Denervation of thenar muscles

Latency greater than 3.5 ms, or asymmetry of conduction velocity of greater than 0.5 m/s vs. opposite hand Latency greater than 4.5 ms, or asymmetry of conduction velocity of greater than 1.0 m/s Fibrillation potentials, sharp waves, increased insertional activity

Percussion test (Tinel sign) Carpal tunnel compression test (Durkan) Hand diagram Hand volume stress test Direct measurement of carpal tunnel pressure Static two-point discrimination

Moving two-point discrimination Vibrometry

Semmes–Weinstein monofilaments

Distal sensory latency and conduction velocity Distal motor latency and conduction velocity Electromyography

Hand volume

Hydrostatic pressure in resting and provocative positioning

Innervation density of fast-adapting fibers

Sens, sensitivity; spec, specificity. (From Abrams R, Meunier, M. Carpal tunnel syndrome. In: Trumble TE, ed. Hand Surgery Update 3, Hand, Elbow, Shoulder. Rosemont, IL: American Society for Surgery of the Hand, 2003:299–312.) (Reprinted with permission from Doyle JR, Tornetta P, Einhorn TA: Orthopaedic Surgery Essentials: Hand and Wrist. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Positive Result Probable CTS (sens 0.75, spec 0.47) Probable CTS if positive at the wrist (sens 0.60, spec 0.67) Probable CTS (sens 0.87, spec 0.90)

Advanced nerve dysfunction

Probable CTS (sens 0.87)

Probable CTS

Advanced motor median nerve compression


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Anterior Interosseous Syndrome Pathophysiology An terior in terosseous syn drom e in volves th e com pression of th e an terior in terosseous n erve (AIN) after it bran ch es from the m edian nerve 4 to 6 cm below the elbow. Sites of com pression in clude th e deep h ead of th e pron ator teres, th e FDS origin , th e FCR origin , an d accessory m uscles such as Gantzer m uscle, which is an accessory head to the FPL. Presentation Since the AIN is a m otor nerve th at innervates the FPL, the pron ator quadratus, an d th e FDS to th e in dex an d little fingers, symptom s involve weakn ess to these m uscles and forearm pain. A

B

Physical Examination Physical exam in ation can dem on strate th e in ability to m ake an “O’’ sign with the index fin ger and th e thum b. No sen sory deficit sh ould be eviden t. Special Studies EMG is n ecessary to m ake th e diagn osis. Delayed con duction should be seen across the site of compression. Differential Diagnosis Th e differen tial diagn osis of th is rare con dition in cludes ten don ruptures an d Parson age–Turn er syn drom e (viral brach ial n euritis).

C

D

Treatment In itial treatm en t in volves 3 to 6 m on th s of observation . If sym ptom s do not resolve, surgical decompression or tendon tran sfers can be con sidered.

Cubital Tunnel Syndrome Cubital tunnel syn drom e is the second m ost com m on upper extrem ity com pressive n europathy.

Figure 15.59 Sites of median nerve compression include (A) ligament of Struthers from supracondylar process, (B) pronator teres, (C) lacertus fibrosis, and (D) fibrous arch of flexor digitorum superficialis. (Reprinted with permission from Doyle JR, Tornetta P, Einhorn TA.Orthopaedic Surgery Essentials: Hand and Wrist. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Treatment If th e diagn osis is m ade, in itial m an agem en t is n on operative with activity m odification to decrease repetitive flexion and pronation. Splinting an d nonsteroidal an tiinflam m atory drugs (NSAIDs) are occasionally helpful. Operative treatm ent, wh ich involves releasing all four poten tial compression sites, is con sidered on ly after a m in im um of 6 m onths of conservative treatm ent.

Pathophysiology/Classification Cubital tunnel syndrom e involves ulnar n erve compression around the elbow, and there are five com m on sites of com pression . Th e arcade of Struth ers is a ban d of fascia th at con n ects th e m edial in term uscular septum to th e m edial h ead of the triceps an d is located approxim ately 8 cm proxim al to the m edial epicondyle (Fig. 15.60). Th is fascia, alon g with th e in term uscular septum an d a hypertroph ied m edial h ead of th e triceps, can com press th e uln ar n erve. Moving distally, the m edial epicon dyle can compress th e ulnar n erve, especially during elbow flexion . Beyon d th e m edial epicon dyle, th e n erve is at risk as it passes un der th e arcuate ligam ent, which connects the m edial epicondyle to the olecran on an d serves as th e roof of th e cubital tun n el. Osborn e fascia, wh ich is a fascial ban d between th e two h eads of th e FCU, is an oth er site of poten tial compression . Fin ally,

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Figure 15.60 (A) The arcade of Struthers. (Reprinted with permission from Doyle JR, Botte MJ. Surgical Anatomy of the Hand and Upper Extremity. Philadelphia, PA: Lippincott Williams & Wilkins, 2003.)

as it exits from un dern eath th e FCU, th e uln ar n erve can be compressed by th e deep flexor pron ator apon eurosis. Less com m on causes of compression in clude anom alous m uscles such as an an con eus epitroch learis. McGowan h as categorized cubital tun n el syn drom e in to three grades. Grade I represents m ild lesions of the ulnar nerve causing paresth esias an d clum siness in the affected hand, with out intrinsic m uscle weakness. Grade II describes in term ediate lesion s causin g weakn ess in th e in terossei an d m uscle wastin g. Grade III den otes severe lesion s that cause interossei paralysis with substan tial han d weakness.

Presentation Cubital tun n el syn drom e usually presen ts with n um bn ess or paresth esias in th e uln ar on e an d a h alf fin gers. Oth er signs an d symptom s include elbow pain , intrin sic weakness, and hand clum siness. Symptom s are usually exacerbated by elbow flexion because th is alters th e sh ape of th e cubital tunnel from an oval to a slit, thereby decreasing its volum e by 50%. Physical Examination Beyond standard m otor and sensory testin g, several provocative physical exam in ation sign s m ay h elp in th e diagn osis. O ften , tappin g over th e cubital tun n el (Tin el sign) an d full-elbow flexion will reproduce the patien ts’ symptom s. A From ent sign is weakness during pinch . Patien ts are asked to pin ch a sh eet of paper between th eir thum b and index finger. Patients with cubital tunn el syndrom e h ave weakn ess in th um b adduction (uln ar n erve)

and compensate by flexing their FPL (AIN). Wartenberg sign is abduction of th e sm all finger during repetitive flexion and exten sion of th e fin gers secon dary to weakn ess of th e th ird palm ar in terosseous m uscle.

Special Studies EMG an d NCS are h elpful in con firm in g th e diagn osis. A n erve conduction velocity of less th an 50 m / s or a drop in conduction velocity of greater than 10 m / s around th e elbow is con sidered abn orm al. Differential Diagnosis Differen tial diagn osis in cludes radiculopathy of C8 –T1, Pancoast tum or, and thoracic outlet syn drom e. Treatment In itial treatm en t in volves NSAIDs an d n igh ttim e exten sion splin ting. If n on operative treatm ent fails or intrin sic atrophy occurs, surgery is in dicated. In situ decompression is the least invasive option but does n ot address the poten tial traction phenom en on that the nerve experiences as the elbow flexes. In gen eral, an terior tran sposition of th e uln ar n erve is th e m ost com m on ly used surgical tech n ique for treating cubital tunn el syn drom e. Although dissection of the nerve risks devascularization, the entire length of the n erve can be freed from com pression . By m ovin g the nerve an terior to the axis of m otion at the elbow, traction on the n erve is also reduced. Two differen t tech n iques h ave been described for th e tran sposition : subm uscular an d subcutan eous. Subcutan eous tran sposition s are tech n ically easier an d preserve the integrity of the flexor–pron ator m uscle


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m ass. However, the superficial position of the nerve risks future injury in thin patients. Subm uscular tran spositions provide a safer h aven for th e uln ar n erve an d are useful in revision cases but do violate th e in tegrity of th e flexor– pron ator m uscles. In gen eral, th is tech n ique sh ould be avoided in throwin g ath letes.

the thum b at the IP join t. Wrist extension rem ains intact because th e ECRL is in n ervated by th e radial n erve.

Ulnar Tunnel Syndrome

Differential Diagnosis In tact wrist exten sion is importan t in differen tiatin g posterior in terosseous syn drom e from a m ore proxim al radial n erve palsy. The other differen tial diagn osis is extensor tendon rupture, wh ich can be differen tiated from posterior in terosseus syn drom e by th e presen ce of th e ten odesis effect (passive finger extension with wrist flexion).

Pathophysiology Ulnar tunnel syndrom e is compression of the uln ar nerve at th e Guyon canal in the wrist. The borders of the Guyon canal are defined by th e flexor retinaculum (floor), the pisiform (uln ar border), th e h ook of th e h am ate (radial border), an d th e volar carpal ligam en t (roof). In th is area, the ulnar nerve bifurcates into the deep m otor branch and the superficial sensory bran ch. Compression is m ost usually secondary to ganglion cysts but can be associated with hook of the ham ate fractures, ulnar artery th rom bosis, an d repetitive traum a.

Special Studies EMG an d NCS are useful for diagn osin g posterior in terosseous syn drom e.

Treatment Once the diagnosis has been m ade, initial treatm ent involves activity m odification and splinting. If this fails, surgical release or tendon transfers m ay be in dicated.

Presentation/Physical Examination Ulnar tun nel syndrom e can be differentiated from cubital tun nel syndrom e by intact sensation over the dorsal uln ar aspect of the hand, wh ich is in nervated by the dorsal sensory nerve.

Radial Tunnel Syndrome

Special Studies EMG an d NCS are im portan t in con firm in g th e location of compression .

Presentation Th e ch ief complain t is pain in th e proxim al radial forearm , and it is usually related to repetitive work activities.

Differential Diagnosis Th e prim ary diagn oses th at n eed to be excluded are com pression of th e uln ar n erve at th e elbow or m ore proxim al nerve compression, especially in the cervical spine.

Physical Examination On physical exam ination, tenderness over the radial nerve distal to th e lateral epicon dyle is on e of th e h allm ark fin dings, and provocative m aneuvers include pain with resisted m iddle finger exten sion. However, both of these findings lack sensitivity and specificity.

Treatment Treatm ent is based on etiology. Sim ilar to other compression n europath ies, splin tin g, NSAIDs, an d activity m odification are attempted prior to surgical decompression.

Posterior Interosseous Syndrome Pathophysiology Posterior interosseous syn drom e refers to compression of the posterior interosseous nerve by one of the following structures: fibrous ban ds anterior to the radiocapitellar join t, th e leash of Hen ry (recurren t radial vessels), th e arcade of Frohse (proxim al edge of the supinator), the distal edge of th e supin ator, or th e fibrous edge of th e ECRB (Fig. 15.61). Presentation/Physical Examination Because th e posterior interosseus n erve is prim arily a m otor n erve, symptom s do n ot in clude pain . In stead, patien ts have difficulty exten ding th eir fingers at the MP join ts an d

Pathophysiology Radial tun n el syn drom e is a pain syn drom e th at is n ot associated with m otor or sensory deficits.

Special Studies EMG an d NCS usually h ave n orm al results. Differential Diagnosis Th e oth er m ajor diagn osis in th e differen tial is lateral epicon dylitis. O n e m eth od to differen tiate th ese two con ditions is selective injection of local anesthetic in to the region of the posterior interosseous nerve. If this leads to pain relief wh ile also causin g a temporary, complete radial n erve palsy, it is con sidered diagn ostic for radial tun nel syndrom e. Un fortun ately, lateral epicon dylitis an d radial tun n el syn drom e can coexist in up to 5% to 10% of patien ts. Treatment Treatm ent is based on extended nonoperative m odalities, such as splinting, activity m odification, and NSAIDs. If sym ptom s persist despite 6 to 9 m onths of con servative treatm ent, surgical decompression can be considered.

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Brachialis

Sensory branch, radial nerve

F

Hueter’s line

R

E Radial recurrent

A

artery PIN Hook on ECRB

Figure 15.61 Sites of radial nerve compresS

Wartenberg Syndrome Pathophysiology Warten berg syndrom e (also kn own as cheiralgia paresthetica) is compression of th e superficial radial n erve, wh ich is a purely sen sory n erve th at run s in th e forearm un dern eath the brach ioradialis and exits dorsally between the tendons of th e brach ioradialis an d ECRL. Com pression occurs secon dary to scissorin g of th e brach ioradialis an d th e ECRL. Handcuffs, tight casts, tight watch bands, an d direct blows have been im plicated in its etiology. Presentation Sym ptom s are paresth esias on th e dorsal radial aspect of the hand; wrist flexion, ulnar deviation, and pronation m ay exacerbate sym ptom s. Physical Examination A positive Tin el sign over th e superficial radial n erve is diagn ostic. Special Studies EMG and NCS are not indicated.

sion in radial tunnel syndrome include (F ) fibrous tissue bands, (R) radial recurrent vessels, (E ) fibrous edge of ECRB, (A) arcade of Frohse, and (S) supinator. ECRB, extensor carpi radialis brevis; PIN, posterior interosseus nerve. (Reprinted with permission from Doyle JR, Tornetta P, Einhorn TA. Orthopaedic Surgery Essentials: Hand and Wrist. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Treatment Treatm ent is alm ost always n onoperative and is based on the rem oval of th e inciting agent.

Thoracic Outlet Syndrome Pathophysiology/Classification Th ere are two types of th oracic outlet syn drom e: vascular an d neurogenic. The vascular type is m ore com m on and usually in volves compression of th e subclavian artery. Th e n eurogenic type is relatively rare, an d th e diagn osis is gen erally a clinical on e. Compression is due to structures such as cervical ribs, th e scalen e m uscles, abnorm al fibrous ban ds, or a hypertroph ic h ead of th e stern ocleidom astoid m uscle comprom ising the space available for th e brachial plexus. Presentation/Mechanism of Injury Th e con dition is foun d m ost com m on ly in youn g or m iddle-aged fem ale population. Symptom s are variable. Classically, it presents in a pattern sim ilar to ulnar nerve compression at the elbow com bined with neck pain an d neurologic symptom s that are worse with overhead activity.


Physical Examination Adson test is specific for thoracic outlet syndrom e and involves obliteration of the radial pulse with slight abduction of the shoulder in the coronal plane and rotation of the n eck to the affected side. Roos test is another useful physical exam in ation for m akin g th e diagn osis. Th e test is positive wh en th ere is n um bn ess or tin glin g of th e uln arsided digits with 90 degrees of abduction of the shoulder, 90 degrees of extern al rotation , an d open in g an d closin g the hands rapidly for up to 3 m inutes. Radiographic Findings Radiograph s of th e n eck an d ch est sh ould be obtain ed to ch eck for cervical ribs, Pancost tum ors, and other chest diseases or an om alies. Special Studies EMG an d NCS can be h elpful in m akin g a diagn osis if a proxim al site of com pression can be iden tified. Differential Diagnosis Cervical radiculopathy and cubital tunnel syndrom e are am ong the chief conditions in the differential diagn osis. Treatment Th is con dition sh ould be treated n on operatively for an exten ded period un less th ere is an un derlyin g structural abnorm ality, such as a cervical rib, th at is found durin g th e initial evaluation. Initial m anagem ent includes stren gthening of the upper extrem ity, trapezius, an d neck m uscles as well as stretch in g of th e n eck an d sh oulder. Weigh t loss an d oth er physical th erapy m odalities can be h elpful. If th ese fail, surgical option s in clude an terior scalen otomy, exploration an d resection of any an om alous fibrous ban ds, or first rib resection th rough an axillary approach .

Degenerative Arthritis Pathophysiology In th e h an d, degen erative arth ritis occurs in diarth rodial join ts th at are subjected to abn orm al loadin g con dition s or th at h ave abn orm al cartilage. It ten ds to be a progressive con dition and is classified as eith er prim ary, when there is n o underlyin g cause, or secon dary, when it is attributed to un derlyin g factors, such as traum a, avascular n ecrosis, developm en tal dysplasia, or oth er disease. Presentation/Physical Examination Com m on ly, patien ts present with pain localized to the involved joint, decreased range of m otion, and a progressive deform ity. Radiographic Findings Th e diagn osis can usually be m ade with radiograph s, wh ich dem on strate four ch aracteristic ch an ges: join t space n arrowin g secon dary to cartilage destruction , periph eral os-

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teophyte form ation , subch on dral sclerosis, an d subch on dral cyst form ation .

Special Studies Radiograph s are usually sufficien t to m ake th e diagn osis of degen erative arth ritis. O ccasion ally, an MRI scan is useful for the diagnosis of early arthritis, and CT scans can poten tially be h elpful in surgical plan n in g. Differential Diagnosis Th e prim ary differen tial diagn osis is in flam m atory arth ritis. Treatment In itial treatm en t is n on operative an d in cludes activity m odification, splinting, and NSAIDs. The second line of n onoperative treatm en t often in cludes in traarticular corticosteroid in jection s th at can provide excellen t symptom atic relief. Surgical in terven tion is con sidered on ly wh en th e patient has deform ity or instability that interferes with function or pain that is refractory to n onoperative treatm ent. Any joint in th e hand an d wrist can be involved, but arth ritis m ost com m only affects th e IP joints, th e first CMC join t, an d th e STT join t. Specific surgical m an agem en t is depen den t on th e patien t an d join t in volved.

DIP Joint Th e DIP join t is on e of th e m ost frequen tly in volved join ts. Presen tin g sym ptom s in clude pain , swellin g, decreased ran ge of m otion , an d deform ity. Heberden n odes are th e characteristic en largem ents of the joint secon dary to th e un derlyin g osteoarth ritis. Mucous cysts, wh ich are gan glion cysts associated with a joint osteophyte, can com m only be seen. Surgical treatm en t is dependent on the stage of th e disease. Mucous cysts can often be m an aged by cyst excision with rem oval of th e un derlyin g osteophyte. More exten sive arth ritis is typically treated with DIP arth rodesis. Fusion is a simpler procedure and has been shown to h ave at least equal results to arth roplasty (Fig. 15.62). The join t is fused in a position of sligh t flexion (5 degrees to 10 degrees) to h elp with fun ction . Multiple tech n iques, in cludin g th e use of K-wires an d com pression screws, h ave been described.

PIP Joint Th e PIP join t is also frequen tly in volved in osteoarth ritis. Arth ritic disease presen ts sim ilarly in th e PIP join t, except th at dorsal join t prom in en ces are called Bouchard nodes. The prim ary differen ce between DIP an d PIP arth ritis is th e preferred form of treatm en t. In th e PIP join t, th e prim ary surgical options are arthroplasty and arthrodesis. Arth roplasty with silicon e or pyrocarbon implan ts can give an approxim ately 60-degree arc of m otion, although im plan t durability an d lon g-term results rem ain question able. Arthrodesis in approxim ately 40 degrees of flexion

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A

B

Figure 15.62 (A) Radiograph and (B) schematic of DIP fusion. DIP, distal interphalangeal. (Reprinted with permission from Strickland JW, Graham TJ. Master Techniques in Orthopaedic Surgery: The Hand. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)

has dem onstrated better results in the index finger, wh ich sees significant lateral stresses during pinch .

MP Joint MP join t arth ritis is sign ifican tly less com m on th an eith er DIP or PIP arth ritis. Disease at th is location is usually secon dary to traum a. Treatm en t is sim ilar to th at at th e PIP join t, with arth roplasty bein g th e preferred surgical option .

TM Joint (First CMC Joint) Th e trapeziom etacarpal join t is on e of th e m ost com m on sites of h and and wrist arth ritis.

Classification Eaton an d Littler categorized TM arth ritis in to four stages (Fig. 15.63). Stage 1 involves a norm al TM join t with possible join t widen in g secon dary to syn ovitis. Stage 2 is

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A

B

C

D Figure 15.63 (A–D) Stages I–IV of thumb carpometacarpal arthritis. (Reprinted with permission from Lotke PA, Abboud JA, Ende J. Lippincott’s Primary Care Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2008.)

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ch aracterized by m ild join t space n arrowin g with osteophytes sm aller th an 2 m m . Stage 3 dem on strates join t space narrowing with osteophytes larger than 2 m m . Stage 4 in volves pan trapezial arth rosis. Th ese stages are im portan t in determ in in g treatm en t.

Presentation/Physical Examination Patien ts usually present with pain at the base of th e thum b. Th ey com m on ly h ave a positive CMC grin d test, wh ich is axial load an d rotation of th e th um b. Careful evaluation of the thum b MP joint m otion m ust be perform ed to assess for MP hyperextension. Radiographic Findings Radiograph ic evaluation in cludes a PA stress view, a lateral view, an d a Robert view (a pron ated an teroposterior view). O n e m ust keep in m in d th at th e radiograph ic severity of th e disease does n ot always correlate with clin ical symptom s. Differential Diagnosis It is imperative to rule out oth er con com itan t diagn oses, such as de Q uervain tenosyn ovitis, stenosin g ten osyn ovitis, CTS, MCP in stability, or oth er wrist arth ridities. Treatment As with arthritis at any other location in the hand and wrist, in itial treatm en t is con servative with activity m odification , thum b spica splinting, and NSAIDs. If nonoperative treatm en t is un successful, surgical treatm en t can be con sidered. Stage 1 disease can be treated with arth roscopic debridem en t an d syn ovectomy, MC exten sion osteotomy to redirect th e MC force dorsally, an d ligam en t recon struction to improve join t laxity. Th e success of any of th ese treatm en ts hinges on the correct staging of the TM arthritis. Stages 2 through 4 imply m ore advanced TM joint degeneration and usually require m ore exten sive procedures. Ligam en t reconstruction tendon interposition (LTRI) arthroplasty was in itially described by Burton an d Pellegrin i an d rem ain s the gold standard for en d-stage pantrapezial arth ritis (Fig. 15.64). Th is procedure involves trapezium excision, palm ar (beak) ligam en t recon struction usin g th e FCR, an d FCR in terposition between th e scaph oid an d first MC. Lon g-term results h ave sh own excellen t pain relief an d predictable in creases in both grip and pinch strength. Hem atom a or distraction arth roplasty is gain in g popularity but risks in clude subsiden ce an d loss of pinch strength . Arthroplasty has dem on strated h igh rates of loosen in g. Trapeziom etacarpal arth rodesis in 30 degrees to 40 degrees of palm ar abduction , 35 degrees of radial abduction , an d 15 degrees of pron ation is favored for youn g laborers. Syn th etic spacers, such as Artelon , h ave recen tly been in troduced an d but lack lon g-term follow-up. Fin ally, with any of th ese procedures, it is im portan t to address any th um b MCP deform ity. Hyperextension of th e th um b MP joint is a characteristic respon se to CMC arth ritis an d m ust be corrected to preven t early failure of a CMC recon struction . Hyperexten -

Figure 15.64 Postoperative radiograph of an LRTI. (Reprinted

with permission from Lotke PA, Abboud JA, Ende J. Lippincott’s Primary Care Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2008.)

sion of less th an 30 degrees requires K-wire stabilization for 4 weeks, whereas hyperexten sion greater than 30 degrees requires volar capsulodesis or MP arth rodesis in 15 degrees of flexion an d 10 degrees of pron ation .

STT Joint Wh ile th e scaph otrapezial–trapezoidal join t is a com m on site of arth ritis, it rarely occurs in isolation. Usually this join t is in volved in pan trapezial arth rosis, wh ich is treated with ligam en t recon struction with ten don in terposition (LRTI) arthroplasty, or in SLAC wrist, where treatm ent is depen den t on th e stage of collapse. However, if th e arth ritis is lim ited to th e STTjoint, STTarth rodesis is a viable option.

SLAC/SNAC Wrist Scaph olun ate advan ced collapse (SLAC) an d scaph oid n on union advan ce collapse (SNAC) are two com m on form s of posttraum atic wrist arthritis.

Pathophysiology SLAC occurs secon dary to disruption of th e scaph olun ate ligam ent and subsequent scaphoid flexion, whereas SNAC results from a scaph oid n on un ion . Classification Watson was th e first to describe th e reproducible pattern of radiocarpal an d in tercarpal degen eration th at occurs in a SLAC wrist. Stage I arth rosis is lim ited to the distal aspect of th e scaph oid an d th e radial styloid. Stage II arth rosis involves the entire radioscaphoid joint. Stage III arthrosis affects the entire radioscaphoid joint and the capitolunate join t. SNAC wrist is less com m on th an SLAC wrist an d h as a differen t pattern of progression . Stage I arth rosis is lim ited to th e distal scaph oid an d radial styloid. Stage II arth rosis is stage I arth rosis plus scaphocapitate arth rosis. Stage III arthrosis is periscaph oid arthrosis.

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Presentation Patients usually present with a rem ote history of a fall on an outstretch ed h an d. In itially, patien ts com plain of wrist pain an d swellin g th at resolves with tim e. Even tually, however, patients develop decreased wrist m otion an d decreased grip/ pinch strength . Physical Examination Physical exam in ation is depen den t on th e stage of disease, but patien ts usually h ave ten dern ess over th e radioscaph oid articulation . Patien ts with an early SLAC wrist m ay have a positive Watson test, as described earlier. Radiographic Findings Radiograph s are imperative in th e diagn osis, stagin g, an d treatm ent of these posttraum atic form s of arth ritis. Differential Diagnosis Th e diagn osis of posttraum atic arth ritis is gen erally straightforward, but SLAC and SNAC m ust be differentiated from each other. Treatment As with other form s of arthritis, conservative m an agem ent in the form of activity restriction, simple splinting, and oral an ti-inflam m atory m edications should be attempted first. For th ose patien ts wh o h ave recalcitran t symptom s, surgical m anagem ent of symptom atic patients is based on the stage of disease. Stage I is best treated with radial styloidectomy an d scaphoid stabilization. If th e scaphoid can be reduced, it should be stabilized with a soft tissue procedure, such as a dorsal capsulodesis or scapholunate recon struction. If

Figure 15.65 Radiographs of a healed scaphoid excision and four corner fusion of the lunate–capitate–hamate–triquetram (SLAC procedure). (Reprinted with permission from Gelberman RH. Master Techniques in Orthopaedic Surgery: The Wrist. Philadelphia, PA: Lippincott Williams & Wilkins, 2002.)

it cannot be reduced, scaphoid stabilization requires a STT fusion. Stage II treatm en t is based on elim inating the radiocarpal join t, an d th is can be accomplish ed by perform ing a PRC, a scaphoid excision and four corn er fusion of th e lun ate–capitate–h am ate–triquetram (SLAC procedure) (Fig. 15.65), or a wrist arthrodesis (Fig. 15.66). In general, eith er a PRC or a SLAC procedure is preferred over a wrist fusion because there is preservation of approxim ately 50% to 60% of wrist m otion. Stage III treatm en t requires either th e SLAC procedure or a total wrist arth rodesis. PRC is con traindicated because capitate wear can lead to accelerated arth rosis between th e capitate and the lunate fossa. Total

B

Figure 15.66 Radiographs of a healed wrist fusion. (Reprinted with

A

permission from Gelberman RH. Master Techniques in Orthopaedic Surgery: The Wrist. Philadelphia, PA: Lippincott Williams & Wilkins, 2002.)

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wrist arth rodesis is an excellent procedure in young laborers, in wh om it reliably decreases pain an d provides a rapid return of grip stren gth . Total wrist arth roplasty is gain in g som e popularity but does not have adequate lon g-term results to com pare with total wrist arthrodesis. Treatm en t of SNAC is sim ilar to th at of SLAC, except that surgery for stage I involves radial styloidectomy and fixation of scaph oid n on un ion with som e form of bon e graft.

INFLAMMATORY ARTHRITIS

Distal Radioulnar Joint Arthritis

Pathophysiology Th e true etiology of RA is un kn own , but it is th ough t to be a com bination of genetic an d en viron m ental factors. Over tim e, RA leads to synovial proliferation within join ts an d around ten dons. Progressive destruction of these tissues results in secondary antibody reactions followed by lysozym e release from wh ite blood cells, oxygen free radical form ation, and collagenase release from the synovium . Cartilage, ligam ent, and tendons are eventually affected, leading to join t pain , in stability, deform ity, an d ten don rupture.

Pathophysiology/Classification DRUJ arth ritis can be posttraum atic or degen erative. Presentation Sym ptom s in clude pain , swellin g, stiffn ess, an d decreased grip stren gth . Physical Examination O n physical exam in ation , pain in located over th e uln ar head and th e DRUJ, an d it is often exacerbated by forearm rotation . Radiographic Findings/Special Studies Radiograph s will sh ow stan dard degen erative ch an ges of the DRUJ. MRI is som etim es helpful in evaluating the TFCC for poten tial tears an d th e lun ate for uln ar impaction syn drom e. Differential Diagnosis Differen tial diagn oses in clude uln ar im paction syn drom e an d TFCC tears. Treatment Surgical treatm en t is in dicated on ly after con servative treatm en t h as failed. For advan ced arth ritis, m ultiple procedures exist th at elim in ate th e distal uln a an d radius articulation , an d each h as its advan tages an d disadvantages. Bowers distal uln a hem iresection an d ten don in terposition preserves th e TFCC in sertion but is con train dicated in uln ar-positive in dividuals, wh o m ay h ave residual uln ocarpal impaction . Darrach distal uln ar resection an d stabilization with ECU suspen sionplasty h as h ad good results in th e low dem an d, elderly population , but has had problem s with stum p in stability and subsequen t weakness in younger patien ts. Th e Sauve–Kapandji procedure retains the distal ulna, fuses the ulnar head to the sigm oid notch, and creates a pseudoarthrosis of the uln ar neck. Th e procedure provides better support for th e carpus than th e distal ulna resection, but complications include proxim al uln ar in stability an d uln ar regen eration with loss of m otion . Fin ally, DRUJ arth roplasty is becom in g in creasin gly popular, but few lon g-term studies exist to accurately assess its outcom es.

Rheumatoid Arthritis RA is a system ic inflam m atory autoim m une disease th at initially affects the soft tissues and secondarily affects the bon e. Approxim ately 1% of th e population is affected, with a fem ale:m ale ratio of 2.5:1. O n set is usually between ages 40 an d 70, an d th e disease h as a progressive course. Han d an d wrist involvem ent is extrem ely com m on.

Classification RA can be classified by stage of join t involvem ent; accurate classification h elps guide treatm en t. Stage 1 is syn ovitis with out deform ity an d can be treated n on operatively. Stage 2 is syn ovitis with passively correctable deform ity. Th is stage is initially treated nonoperatively, but if symptom s persist, ten osyn ovectom y m ay be n ecessary. Stage 3 is fixed deform ity with out join t ch an ges an d is best treated with surgical reconstruction. Stage 4 is articular destruction; salvage surgery such as arthrodesis or arthroplasty is required. Presentation/Physical Examination Th e diagn osis of RA requires th at at least four of th e seven followin g criteria be present: periarticular m orn ing stiffn ess lastin g for at least 1 h our per day for at least 6 weeks, sim ultan eous arthritis an d synovitis in three or m ore joints for at least 6 weeks, arthritis of the hand joints for at least 6 weeks, sym m etric arth ritis presen t for at least 6 weeks, presen ce of rh eum atoid n odules, elevated rh eum atoid factor titer, and radiographic evidence of subchondral erosions or osteopen ia adjacen t to in volved join ts. Ten don ruptures are com m on in patien ts with RA. Etiologies in clude syn ovitis, attrition al wear from osteophytes, an d traum atic or iatrogenic causes. The Vaughn –Jackson lesion results from a subluxated, osteophytic, and sharp uln ar h ead th at causes EDM an d EDC ten don ruptures. A Mannerfelt lesion is a scaph otrapezial joint osteophyte that causes FPL rupture. The diagnosis of ten don rupture is relatively straightforward: patients will have norm al passive m otion but will be unable to actively m ove the joint. In addition, there is a loss of the tenodesis effect. Deform ity results wh en MP join ts drift in to uln ar deviation . This instability is secondary to synovitis, which atten uates th e radial exten sor h ood sagittal fibers an d causes


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the two option s is dependent on the join t an d is sim ilar to the treatm ent of en d-stage osteoarthritis.

Psoriatic Arthritis Psoriatic arth ritis is a relatively un com m on arth ritis an d presen ts on ly in 5% to 10% of patien ts with psoriasis.

Pathophysiology Synovial disease in the hand leads to either osteolysis or ankylosis and autofusion. Osteolysis m ost com m only involves the DIP joint with erosion of the m iddle phalangeal con dyles in to a spike, creatin g th e classic “pen cil-in -cup’’ deform ity. Spon tan eous fusion occurs m ain ly at th e DIP join t an d occasion ally at th e PIP join ts.

Figure 15.67 Typical ulnarly deviated hand of a patient with

rheumatoid arthritis. (Reprinted with permission from Strickland JW, Graham TJ. Master Techniques in Orthopaedic Surgery: The Hand. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)

ulnar subluxation of th e extensor tendon (Fig. 15.67). Th e PIP join ts usually progress to a bouton n iere deform ity after PIP syn ovitis weaken s th e cen tral slip.

Presentation/Physical Examination Patien ts usually h ave classic fin din gs of psoriasis, such as th e scaly eryth em atous rash , before developin g join t sym ptom s. Early findings include nail pitting an d sausage digits. However, once sign ifican t arthritis develops, it can affect all finger joints and cause severe deform ity, which is often referred to as arthritis mutilans. Fin ger telescoping can also occur, wh ich gives a ch aracteristic appearan ce called “opera glass han d.’’

Radiographic Findings/Special Studies RA is characterized by severe deform ity, periarticular erosions, an d osteopenia, wh ich distinguishes it from osteoarth ritis.

Radiographic Findings As previously described, radiograph s frequen tly sh ow PIP fusions, MP erosions, and wrist autofusions. The classic deform ity seen on radiograph s is th e DIP “pen cil-in -cup’’ deform ity.

Differential Diagnosis In itially, RA m ust be distin guish ed from osteoarth ritis an d oth er form s of in flam m atory arth ritis. O n ce th is is don e, m ore specific clinical diagnoses have to be m ade. For instan ce, tendon ruptures m ust be differentiated from tendon subluxation and peripheral neuropathy.

Differential Diagnosis Psoriatic arth ritis m ust be differen tiated from osteoarth ritis, RA, an d other inflam m atory arth opathies. This usually can be accom plish ed with a th orough h istory an d a search for the characteristic nonm usculoskeletal fin dings.

Treatment In itial treatm en t of acute flares is based on rest an d activity m odification. However, th e current m ainstay of treatm en t is early an d aggressive use of disease-m odifyin g an tirh eum atic drugs (DMARDs). These drugs, such as TNF-α inh ibitors, have had a dram atic effect on symptom s an d disease progression . By doin g so, th ey h ave m arkedly reduced the need for surgical treatm ent of RA patients. However, surgical intervention is still n ecessary in m anaging certain aspects of th e disease. Persistent tenosynovitis is best m anaged by complete syn ovectom y. Ten don ruptures are treated by resection of the offen ding bony prom in en ce, ten osynovectomy, and recon struction via tendon tran sfers. Later stages of RA, which usually exh ibit n ear-com plete articular destruction , are best treated by arthrodesis or arthroplasty. The choice between

Treatment Medical treatm ent is sim ilar to that used for RA. Operative treatm ent prim arily involves arthroplasty or arthodesis of arth ritic joints.

Crystalline Arthropathy Gout an d pseudogout are th e m ost com m on crystallin e arth ropathies.

Pathophysiology/Classification Gout can be separated in to prim ary gout, wh ich is idiopath ic, an d secon dary gout, wh ich results from an im balance in uric acid m etabolism Pseudogout or calcium pyroph osph ate deposition disease is th ough t to be due to increased level of calcium or pyroph osph ate in cartilage.

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Presentation/Physical Examination Gouty attacks presen t with th e sudden on set of a warm , swollen, eryth em atous, and painful joint. Pseudogout can presen t sim ilarly, but usually th e attack is less severe. Arth ritis an d ten don ruptures can occur secon dary to ch ron ic in flam m atory ch an ges. Radiographic Findings/Special Studies Radiograph in gout can dem on strate soft tissue den sities (toph i) an d articular erosion . Pseudogout appears as calcification s in th e cartilage, m ost com m on ly seen in th e TFCC. For both con dition s, th e diagn osis is m ade on th e basis of join t fluid aspiration an d an alysis. Uric acid crystals in gout are n egatively birefrin gen t an d n eedle-like un der polarized m icroscopy, wh ereas calcium pyroph osph ate crystals from pseudogout are weakly positively birefrin gen t an d rh om boid sh aped.

bilization . For both diagn oses, surgery is lim ited to toph i excision , ten osyn ovectom ies, an d arth rodesis/ arth roplasty of en d-stage arth ritic join ts.

Hand Stiffness Hand stiffn ess is a com m on problem that has m any etiologies. To appropriately treat the stiffness, the correct diagn osis m ust first be m ade.

Differential Diagnosis In fection can often be con fused with crystallin e arth ropath ies sin ce both presen t as h ot, swollen join ts. Th e diagn osis of in fection can usually be excluded on th e basis of an alysis of th e join t fluid cell coun t an d of th e Gram stain .

Classification Stiffn ess can be due to eith er extrin sic or in trin sic causes. Extrin sic stiffn ess in volves ten don s th at origin ate proxim al to th e wrist, wh ereas th e source of in trin sic tigh tn ess originates at or distal to the wrist. Extrinsic exten sor tightness m anifests as lim ited IP joint flexion when the MP joint is h eld in flexion. Wh en th e MP join t is exten ded, m otion is improved. Sim ilarly, extrinsic flexor tightn ess m anifests as lim ited IP joint extension when the MP join t is held in exten sion ; th is is im proved with MP join t flexion . O n th e oth er h an d, in trin sic tigh tn ess results in a positive Bun n ell intrinsic tigh tness test (Fig. 15.68), which dem onstrates less IP join t flexion with th e MP join t in exten sion compared with wh en th e MP join t is in flexion .

Treatment Acute gout attacks are treated with colchicin e and/ or indom eth acin . In between flares, allopurin ol h elps m etabolize uric acid an d preven t future attacks. Pseudogout is m ain ly treated symptom atically with NSAIDs an d im m o-

Presentation/Physical Examination History sh ould address th e onset of symptom s, the progression of symptom s, an d any associated traum a. Exam ination sh ould in clude in spection for deform ity and swelling, evaluation of active an d passive ran ge of m otion , an d testin g

Figure

A

B

15.68 (A, B) Intrinsic tightness test.

(Reprinted with permission from Doyle JR, Botte MJ. Surgical Anatomy of the Hand and Upper Extremity. Philadelphia, PA: Lippincott Williams & Wilkins, 2003.)


of n eurologic fun ction . Th e discrepan cy between active an d passive m otion is particularly im portan t. For example, join t con tracture will have an equal decrease in passive and active ran ges of m otion , regardless of th e position of th e adjacen t join ts. Th is differs from stiffn ess secon dary to ten don ruptures or adhesion s, in which ran ge of m otion is affected by the type of m ovem en t and the position of adjacent joints.

Radiographic Findings/Special Studies Radiograph s are n ecessary on ly wh en stiffn ess is th ough t to be secon dary to a bony process, such as a fracture, nonunion, joint dislocation , or arthritis. Treatment In itial treatm en t for h an d stiffn ess in volves splin tin g an d aggressive range of m otion exercises in an organized han d therapy program . If conservative m anagem en t fails, surgery sh ould be con sidered. The specifics of surgery are depen den t on th e structures th at are con tracted, but in gen eral, all structures that are tigh t starting with the skin an d ending with the join t capsule m ust be released until acceptable ran ge of m otion h as been obtain ed. Postoperatively, early ran ge of m otion exercises are imperative for a successful result.

Complex Regional Pain Syndrome Complex regional pain syndrom e (CRPS) is th e new nom en clature for the con dition form erly kn own as reflex sympathetic dystrophy ( RSD) or causalgia. CRPS is a diagn osis of exclusion, an d its h allm ark symptom is pain out of proportion to th e in citin g even t. It is defin ed by th e presen ce of pain , fun ction al deficits, an d objective sympath etic nervous system dysfun ction.

Pathophysiology Th e exact etiology or m ech an ism of CRPS is un kn own . It has been hypothesized to occur from a positive feedback cycle in which peripheral nocicepter activation causes a spinal cord m ediated reflex, which in turn activates the efferent sympathetic system . Another hypoth esis is that CRPS is caused by exaggeration of the peripheral neural inflam m atory respon se to tissue in jury. Classification Th ere are two types of CRPS. Type I, wh ich correspon ds to th e classic RSD, is pain out of proportion to th e in itial noxious even t that cannot be linked to any path ologic process. Type II, which corresponds to causalgia, is pain out of proportion to th e in itial n oxious even t th at is associated with an iden tifiable n erve lesion . Presentation/Physical Examination CRPS develops after an initial painful or noxious event, an d often is associated with traum a. Subsequently, patients complain of pain with light tough (allodynia), in creased

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sen sitivity to touch (hyperesthesia), pain at rest (hyperpath ia), burn in g pain , an d various extrem ity ch an ges correspon din g to th e stage of disease. Specifically, th ree stages h ave been described. Stage I in volves sign ifican t extrem ity swellin g an d edem a, with hyperh idrosis. Stage II is th e dystroph ic ph ase ch aracterized by m arked stiffn ess. In th is stage, skin ch an ges such as loss of creases, loss of hair, and decreased m oisture are eviden t. Stage III is th e atroph ic stage, durin g wh ich th e lim b becom es h ardly usable.

Radiographic Findings/Special Studies No im agin g study is diagn ostic. Radiograph s m ay dem on strate patchy osteopenia, and bon e scans m ay sh ow diffuse uptake in th e in volved join ts. Differential Diagnosis As previously m en tion ed, CRPS is a diagn osis of exclusion . Th erefore, any an d all diagn oses th at could poten tially lead to sim ilar symptom s m ust be ruled out before m aking the diagn osis. Treatment Treatm ent is based on early diagnosis and aggressive m ultidisciplinary treatm ent. Occupational and physical therapy are helpful in decreasin g pain, reducing edem a, and lim iting stiffness. Many m edication s, including calcium channel blockers, antidepressants, and anticonvulsants, h ave dem on strated som e success. Oth er m odes of treatm ent such as transcutan eous electrical n erve stim ulators (TENSs), autonom ic blocks, and surgical sympathectom ies h ave proven beneficial in som e patien ts. Th ese m odalities are usually best prescribed and coordinated by pain specialists.

Dupuytren Disease Dupuytren disease is a con dition th at is ch aracterized by n odule an d cord form ation in previously n orm al fascial tissues of the han d, with progressive flexion contractures of th e MP an d/ or PIP join ts. It prim arily affects 40- to 60year-old m en of Northern European an cestry. Although it can be in h erited as an autosom al dom in an t con dition with variable penetrance, it is m ost frequently sporadic. It h as been lin ked to alcoh ol, diabetes, HIV, an d sm okin g.

Pathophysiology Th e exact etiology of Dupuytren disease is un kn own , but m any factors have been proposed. Th ese include oxygen free radical form ation secondary to hypoxia and dysfun ction of m ultiple growth factors including PDGF and TGFB1. The cell respon sible for th e disease h as been identified as the myofibroblast, which has features of both sm ooth m uscle cells and fibroblasts. These cells are responsible for the three stages of the disease. The proliferative stage is a vascular stage when the num ber of myofibroblasts increases. Th e involutional stage involves alignin g of the

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myofibroblasts and th e increasing ratio of type III to type I collagen . Th e residual stage dem on strates disappearan ce of th e m yofibroblasts an d replacem en t with fibrous tissue. The specific fascial tissues in volved in the disease are the pretendin ous bands, the ligam ents of Legueu and Juvara, the spiral bands, the natatory ligam ent, the lateral digital sh eet, an d Grayson ligam en t (Fig. 15.69). Clelan d ligam en ts are n ot affected by th e disease. Wh en th e ban ds becom e th icken ed an d con tracted, th ey becom e cords. Th e com m on cords are th e cen tral cord, the ADM cord, th e spi-

ral cord, th e retrovascular cord, th e lateral cord, th e n atatory cord, an d th e first web’s in tercom m issural cord (Fig. 15.70). The central cord has no fascial precursor but is a con tinuation of the pretendinous band. Th e spiral cord arises from four structures: the pretendinous band, the spiral ban ds, th e lateral digital sh eath s, an d Grayson ligam en t. Th is cord passes ben eath th e n eurovascular bun dle an d brin gs it m ore superficial.

Presentation Patients usually presen t with sin gle or m ultiple nodules an d/or cords in th e palm ar fascia of the h and (Fig. 15.71). Although these n odules are often pain less, they can cause skin dim pling, flexion con tractures of th e MP and PIP join ts, an d web space con tractures. Th ese con tractures often lim it fun ction and usually progress over tim e. Eventually, patien ts com plain of difficulty with fin e m otor m ovem en t. Physical Examination Physical exam in ation varies depen din g on th e severity of the disease. Range of m otion of th e involved joints should be accurately assessed. Distal n eurovascular fun ction m ust be con firm ed, especially if operative in terven tion is bein g con sidered. Radiographic Findings Radiograph s are usually un n ecessary to m ake th e diagn osis.

Figure 15.69 Normal components of palmar and digital fas-

cia. (Reprinted with permission from Doyle JR, Botte MJ. Surgical Anatomy of the Hand and Upper Extremity. Philadelphia, PA: Lippincott Williams & Wilkins, 2003.)

Treatment Treatm ent is based on the severity of the disease. Nonoperative treatm en t is useful in th e early stages of th e disease wh en th e patien t h as n o pain an d n o fun ction al lim itation s. However, as th e disease progresses, surgical treatm ent is indicated for MP join t con tractures greater th an 30 degrees an d any PIP joint contracture. Surgical options include palm ar fasciotom ies, partial palm ar fasciectom ies, an d complete palm ar fasciectom ies. Fasciotom ies allow joint con tracture release but have higher rates of recurrence an d increased in cidence of n eurovascular injuries. Complete fasciectom ies have fallen out of favor due to the in creased risk of complication s such as n eurovascular in jury an d in fection. Partial fasciectom ies are a comprom ise between the oth er two procedures. With any procedure, careful dissection m ust be perform ed to prevent injury to th e neurovascular bun dle. Th e skin is often left open to preven t h em atom a form ation , wh ich h as been im plicated in flair reaction an d RSD. O verall, th e results of th e procedures are relatively good, but th e recurren ce rate rem ain s approxim ately 10% per year. Recen tly, en zym atic fasciotomy with clostridial collagen ase in jections h as sh own som e prom isin g results. On e ran dom ized con trolled trial sh owed a 90% success rate, with low recurren ce rate. However, lon g-term results are pen din g.


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Figure 15.70 Changes in palmar and digital fascia seen in Dupuytren disease. (Reprinted with permission from Doyle JR, Botte MJ. Surgical Anatomy of the Hand and Upper Extremity. Philadelphia, PA: Lippincott Williams & Wilkins, 2003.)

A

B Figure 15.71 (A, B) Dupuytren cords. (Reprinted with permission from Lotke PA, Abboud JA, Ende J. Lippincott’s Primary Care Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2008.)

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TENDINOPATHIES Ten din opath ies are com m on con dition s of th e h an d an d wrist. Th e flexor/exten sor tendons are restrained from displacin g forces by th e flexor retin aculum , th e exten sor retinaculum , an d the digital fibro-osseous pulleys. If th ere is th icken in g of th ese restrain ts or of th eir con ten ts, th e ten don s becom e compressed an d th e ten osyn ovium can becom e in flam ed. Motion of th e ten don is altered, an d a vicious cycle of worsen in g pain an d decreased ran ge of m otion results.

Trigger Finger Trigger fin ger or sten osin g ten osyn ovitis is a com m on problem th at is ch aracterized by th e in ability to flex or exten d a digit. Norm ally, th e flexor ten don s can glide sm ooth ly through the fibro-osseous flexor pulley system . However, in trigger digits, a discrepan cy exists between th e size of th e flexor ten don and of the tendon sh eath, and this leads to m ech an ical impin gem en t.

Pathophysiology/Classification Trigger fin ger exists in two form s. Nodular ten osyn ovitis is caused by th icken in g of th e flexor ten don on th e distal edge of th e A1 pulley an d h as a distin ct n odule. Diffuse ten osyn ovitis is caused by diffuse th icken in g of th e flexor ten osyn ovium . Presentation Idiopath ic trigger fin ger often occurs in m iddle-aged wom en , wh ereas secon dary trigger fin ger is com m on ly seen in patien ts with diabetes, hypothyroidism , RA, ch ron ic renal disease, or other inflam m atory disease. All of th ese patien ts usually com plain of palm ar pain an d stiffn ess of th e in volved fin ger. Depen din g on th e severity, patien ts m ay also sen se crepitus, catch in g, or lockin g of th e fin ger. Physical Examination O n exam in ation , a palpable n odule can often be felt over the A1 pulley. Patien ts are tender to palpation over the nodule. Visible catch in g or lockin g can usually be seen with active ran ge of m otion . Radiographic Findings Radiograph s are usually un n ecessary to m ake th e diagn osis. Differential Diagnosis Differen tial diagn oses in clude lockin g secon dary to im pin gem en t of th e collateral ligam en ts on a prom in en t MC head condyle, FDP avulsion or rupture, MP dislocation , an d exten sor ten don rupture. Treatment Treatm en t is based on th e severity of disease. In itially, m ost patien ts are treated n on operatively. Th is usually in volves

Figure 15.72 Trigger finger injection. (Reprinted with permission from Lotke PA, Abboud JA, Ende J. Lippincott’s Primary Care Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2008.)

NSAIDs to decrease in flam m ation , exten sion splin tin g at n igh t, and activity m odification . Th e n ext step in treatm ent is a corticosteroid injection , which is indicated early in the disease process (Fig. 15.72). A sin gle in jection h as been sh own to effectively relieve symptom s in 47% to 87% of patien ts. A h igh er rate of failure h as been seen in patien ts with diabetes, a lon g h istory of triggerin g, an d m ultiple in volved digits. If nonoperative treatm en t fails or if a patient h as a locked digit, surgery is in dicated. Th e procedure of ch oice is release of th e A1 pulley (Fig. 15.73). Th e gold stan dard is an open surgical release, but recen tly som e surgeon s h ave been perform in g the release percutan eously. Th e prim ary risk of either procedure is in jury to the digital n erve. Overall, th e surgery has a greater than 90% success rate.

de Quervain Tenosynovitis Pathophysiology de Quervain ten osyn ovitis is ten osyn ovitis of th e first dorsal com partm ent of th e wrist. Com m on causes include repetitive use, in flam m atory arth ritis, an d traum a. New m others often are diagnosed with de Quervain tenosynovitis as a result of liftin g th eir ch ildren with radial/ uln ar deviation of th e wrists. Presentation de Quervain ten osyn ovitis occurs prim arily in m iddle-aged patien ts an d presen ts with radial-sided wrist pain . Th e pain is exacerbated by thum b m ovem ents and m ay radiate distally or proxim ally. Physical Examination On exam ination, patien ts are tender over the first dorsal compartm ent of the wrist. Most patients have a positive Fin kelstein test, wh ich is pain with forced uln ar deviation of th e wrist with th e th um b in side a clen ch ed fist.


A

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B Figure 15.73 (A, B) Operative pictures of a trigger finger release. (Reprinted with permission from Lotke PA, Abboud JA, Ende J. Lippincott’s Primary Care Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins, 2008.)

Radiographic Findings Radiograph s are un n ecessary in m akin g th e diagn osis but m ay be helpful to rule out oth er conditions. Differential Diagnosis It is importan t to exclude oth er causes of radial-sided wrist pain , such as CMC arth ritis, in tersection syn drom e, Warten berg syn drom e, an d scaph oid fracture. Treatment In itial treatm en t is n on operative with th um b spica splin ting and oral NSAIDs. A corticosteroid injection can also be perform ed to decrease in flam m ation an d is successful approxim ately 60% of the tim e. If conservative treatm ent fails, surgery con sistin g of release of th e first dorsal com partm en t is in dicated. Given th at th e APL often h as several slips, great care m ust be taken to release all tendon sh eaths of both th e APL an d EPB. Th e ten don sh eath s sh ould be released on th eir uln ar aspect to preven t radial subluxation of th e compartm en t. Th e sen sory bran ch es of th e radial nerve have to be protected to avoid neurom a form ation (Fig. 15.74).

Intersection Syndrome Pathophysiology In tersection syn drom e is in flam m ation of th e secon d dorsal exten sor compartm ent secondary to overuse. It is ch aracteristically seen in rowers. Presentation/Physical Examination Patients usually present with pain approxim ately 4 cm proxim al to th e wrist (Fig. 15.75). On exam in ation , th e secon d dorsal compartm ent is boggy and crepitation can be felt.

Figure 15.74 Anatomy pertinent to deQuervain’s tenosynovitis.

(Reprinted with permission from Doyle JR and Botte MJ: Surgical Anatomy of the Hand and Upper Extremity. Philadelphia: Lippincott Williams & Wilkins, 2003.)

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ECRL ECRB APL EPB

4 cm

Site of physical findings

Site of tenosynovitis

Figure 15.75 Intersection syndrome. ECRL, extensor carpi ra-

dialis longus; ECRB, extensor carpi radialis brevis; APL, abductor pollicis longus; EPB, extensor pollicis brevis. (Reprinted with permission from Doyle JR, Tornetta P, Einhorn TA. Orthopaedic Surgery Essentials: Hand and Wrist. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Radiographic Findings Radiograph s are un n ecessary to diagn ose in tersection syn drom e.

Pathophysiology Th e h an d is con stan tly exposed to both m in or an d m ajor traum a, wh ich can disrupt th e skin an d allow in oculation of bacteria. On ce bacteria have penetrated the skin, the progression of infection is dependent on several factors, including the location, the virulence of the organ ism , an d the im m une status of the host. The m ost com m on organism s involved in h and infections are Staphylococcus aureus an d Streptococcus, but others are encountered. Presentation As with oth er locations in the body, hand infections present with pain , warm th , eryth em a, an d swellin g. In fection s th at becom e system ic can cause fevers, ch ills, an d n igh t sweats. Often, inflam m atory m arkers, such as C-reactive protein (CRP), erythrocyte sedim entation rate (ESR), and white blood cell (WBC) coun t are elevated. History/Physical Examination A complete history is vital to appropriately treating infections. Key components of the history are m ode of inoculation , duration of symptom s, ch an ge in sym ptom s, previous treatm en ts, en viron m en tal exposures, occupation travel h istory, an d im m une status. On exam ination, it is im portan t to determ in e th e exact location of th e in fection . For instance, cellulitis is a superficial tissue infection and does n ot in volve any deep loculated areas of purulen ce. On the oth er h an d, septic arth ritis affects join ts cause m icrom otion pain and can lead to deep, fluctuant abscesses. Radiographic Findings Radiograph ic fin din gs in osteomyelitis in clude osteopen ia, bony erosion s, lytic lesion s. For oth er soft tissue in fection s, radiograph s are less h elpful but can som etim es dem on strate soft tissue swelling or subcutaneous air.

Differential Diagnosis Th e differen tial diagn osis is sim ilar to th at of de Q uervain syn drom e.

Special Studies MRIs and ultrasounds are the best m odalities for accurately localizin g and diagnosin g deep infections. For septic join ts, aspiration an d fluid analysis is diagnostic. Nuclear m edicin e testin g m ay be ben eficial in diagn osin g osteomyelitis.

Treatment Th e m ain stays of treatm en t are activity m odification , wrist splinting, and oral NSAIDs. Corticosteroid in jections are used if th ese m odalities fail. Surgery, wh ich in volves com plete release of th e secon d com partm en t, is in dicated after failure of n on operative m an agem en t.

Differential Diagnosis Tum ors and crystalline arth ropathies can often present sim ilar to in fection . Another com m on condition that can presen t like in fection is pyogen ic gran ulom a. Th ese lesion s form secondary to penetratin g traum a an d present as a red, friable m ass; treatm ent con sists of cauterization.

HAND INFECTIONS Although the hand is well perfused, frequent breaks in the skin and exposure to outside pathogen s m akes it a frequent site of infection.

Treatment In gen eral, all in fection s of th e h an d are treated sim ilarly with im m obilization , elevation , an tibiotics, an d operative debridem en t if n ecessary. Th e specifics of treatm en t are based on th e severity of th e path ogen an d th e location of th e in fection . Em piric an tibiotics, wh ich sh ould be used


un til culture results are available, h ave h istorically covered gram -positive cocci. With th e recen t in creased in ciden ce of com m un ity-acquired m eth icillin -resistan t S. aureus, one m ust be sure that this pathogen is also covered. Mild infection s can be treated with oral antibiotics, wh ereas severe infections require intravenous antibiotics.

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Nail plate Matrix cells Area of chronic paronychia

Paronychia Pathophysiology Paronychia is an infection un der the eponych ial fold, and it usually occurs secondary to m an icures, hang nails, or nail biting. The m ost com m on path ogen responsible is S. aureus. Presentation/Physical Examination Paronychia usually presen t with pain , swelling, an d redness along the nail fold. Spontaneous drainage of purulen t m aterial can also be seen. Radiographic Findings Radiograph s can evaluate th e distal ph alan x for osteomyelitis. Differential Diagnosis Severe paronych ias can progress to felon s. Treatment Th e treatm en t of paronych ia is based on th e stage of th e infection. Early stages can be treated with warm water soaks an d oral antibiotics. As the infection progresses, an irrigation and debridem en t (I&D) m ust be perform ed to decom press th e pus. Th is can usually be perform ed in th e em ergen cy departm en t settin g, un der digital block. Th e eponych ial fold is separated from th e n ail, an d often the involved portion of the nail is rem oved. After irrigation, the fold should be stented open with gauze to allow con tinued drain age. Ch ron ic paronych ia is usually caused by Candida albicans, is m ore resistan t to treatm en t, an d m ay require m arsupialization for complete eradication (Fig. 15.76).

Felon Pathophysiology A felon is an abscess of th e fin ger pulp overlying the distal ph alan x, an d it usually occurs secon dary to m in or traum a or exten sion of a paronych ia. Sim ilar to paronych ia, felon s are m ost frequently caused by S. aureus. Presentation/Physical Examination Th ese in fection s presen t with ten se swellin g, warm th , redness, an d pain localized to the finger pulp. Radiographic Findings Radiograph s are ben eficial in excludin g osteomyelitis of the underlying distal phalanx in severe infections.

A

B

Figure 15.76 Surgical management of chronic paronychia with

marsupialization technique. (Reprinted with permission from Doyle JR, Tornetta P, Einhorn TA. Orthopaedic Surgery Essentials: Hand and Wrist. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Differential Diagnosis Severe infection can progress to adjacent structures. Therefore, osteomyelitis of the distal phalanx, septic arth ritis of th e PIP join t, an d pyogen ic flexor ten osyn ovitis m ust be excluded. Treatment Early cases can be treated with elevation , warm soaks, an d antibiotics. However, the m ajority of felons require surgical decom pression of all th e pulp’s m ultiple compartm en ts. Th e procedure can usually be perform ed in th e em ergen cy departm en t settin g, un der digital block. Wh ile m any in cision s h ave been described, th e m ost com m on approach is through a m idaxial, longitudinal incision. To avoid scar sensitivity, the in cision should be placed on th e ulnar side of th e in dex fin ger, lon g fin ger, an d rin g fin ger, but on th e radial sides of th e th um b an d sm all fin ger. Th e digital n eurovascular bun dle m ust be avoided, an d th en scissors or clamps are used to decompress all th e sm all com partm ents. The wound is packed, and twice-a-day soaks are started after 24 hours. Empiric antibiotics covering gram positive cocci are started un til culture results are fin alized.

Herpetic Whitlow Pathophysiology Herpetic whitlow is a fin ger infection caused by the herpes sim plex virus. Most com m only, it is transm itted by oral secretion s; an d th erefore, ch ildren and health care workers are at risk. Presentation/Physical Examination Th e in fection presen ts as a sin gle or a group of pain ful vesicles over the fingertips or other regions of th e hand (Fig. 15.77). Th e pain m ay precede the appearan ce of th e vesicles.

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A

B

Figure 15.77 Three phases of herpes simplex

C

Radiographic Findings/Special Studies Sin ce th e diagn osis is m ade by h istory an d physical exam ination, no im aging m odalities are n ecessary. Tzan ck sm ear an d viral culture can be used to con firm th e diagn osis. Differential Diagnosis Bacterial infection m ust be excluded. Treatment Herpetic wh itlows are usually self-lim ited with a 7- to 14day course, durin g wh ich th e vesicles coalesce, un roof, form ulcers, and then epithelialize. Until epithelialization, the patien t is considered contagious. Surgical incision and drain age m ust be avoided at all costs because th is can lead to dissem in ated in fection or superin fection .

infection: (A) erythematous, (B) pustular, and (C) desquamation. (Reprinted with permission from Doyle JR, Tornetta P, Einhorn TA. Orthopaedic Surgery Essentials: Hand and Wrist. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Pyogenic Flexor Tenosynovitis Pyogen ic flexor ten osyn ovitis is purulen t in fection of th e flexor ten don sheath. It causes scarring and adhesions of th e flexor ten don s an d leads to sign ifican tly im paired m otion.

Pathophysiology In fection of th e ten don sh eath usually results from direct inoculation or from the spread from adjacent infection. If treatm ent is inadequate or delayed, infection can spread to adjacent tendon sheaths or to the radial/ulna bursa. Th e radial an d uln a bursa can th eoretically com m un icate through Parona space in th e wrist, form ing what is kn own as a horseshoe abscess.


Presentation/Physical Examination Diagn osis is usually based on th e Kan avel four cardin al signs, which are severe pain to passive exten sion, fusiform swellin g of th e involved digit (sausage digit), tenderness along th e flexor tendon sheath , an d partial flexed resting posture of th e fin ger Differential Diagnosis Th e differen tial diagn osis for pyogen ic ten osyn ovitis in cludes gout, other deep infections of th e hand, an d inflam m atory arthropathy. Treatment Treatm ent is based on tim e to presentation. Early stages of th e disease (< 24 h ours) can som etim es be m an aged with elevation , im m obilization , in traven ous an tibiotics, an d close observation. However, if the infection worsens or if th e patien t presen ts beyon d 24 h ours, irrigation an d debridem en t of th e flexor ten don sh eath is m an datory. Th is can be accomplished via an open Brunner zigzag incision or a m idaxial in cision . Altern atively, it can be perform ed closed via a proxim al and a distal incision into the ten don sh eath , followed by irrigation of th e sh eath usin g an an giocath eter (Fig. 15.78).

Abscesses Th e h an d con tain s m any deep spaces wh ere abscesses can occur. Th ese in clude th e subcutan eous space, th e dorsal subaponeurotic space, th e then ar space, the hypoth enar space, an d th e interdigital web spaces.

Pathophysiology Most abscesses occur from a penetrating traum a or from con tiguous in fection of an adjacent area. However, a collar button abscess is an abscess of th e web space th at assum es

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a volar to dorsal hourglass configuration due to th e superficial transverse MC ligam en t. This abscess often form s in laborers from a palm ar blister, callus, or fissure.

Presentation/Physical Examination Patien ts usually presen t with pain , eryth em a, warm th , an d swellin g. Th e swellin g m ay be diffuse or localized. For example, m id palm ar abscesses h ave a loss of the norm al palm ar con cavity. Also, patien ts m ay h ave lim ited, pain ful finger m otion depending on the location of the abscess. Radiographic Findings/Special Studies If a patien t presen ts with diffuse swellin g, an MRI is useful in differentiatin g cellulitis from an abscess. Differential Diagnosis Abscesses can m im ic any adjacen t in fection . Tum or m ust also be excluded. Treatment All abscesses are treated with irrigation an d debridem en t, but specific tech n iques are depen den t on th e exact location of the infection . Certain infections, such as a collar button abscess or a th en ar space abscess, m ay require two incisions. The wounds should be packed open, an d soaks sh ould be in itiated 1 to 2 days after surgery. Following surgery, appropriate in travenous antibiotics, elevation, an d im m obilization are critical for a successful outcom e.

Septic Arthritis Pathophysiology Septic arth ritis is infection of the join t, an d it can be caused by direct inoculation from traum a or by secondary spread. Once there is infection in the joint, cartilage destruction will occur from th e in flam m atory process. Th e m ost com m on ly involved pathogens are S. aureus an d Streptococcus. Presentation/Physical Examination Patien ts with septic arth ritis com plain of eryth em a, swellin g, an d sign ifican t joint pain th at causes pain even with m icrom otion of th e join t.

Figure 15.78 Flexor tendon sheath I&D. (Reprinted with per-

mission from Strickland JW, Graham TJ. Master Techniques in Orthopaedic Surgery: The Hand. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)

Radiographic Finding/Special Studies Radiograph s are m an datory to evaluate th e join t for fractures or foreign bodies. For instance, fight bites often lead to septic arthritis of the MP joint, and chipped teeth can occasion ally be seen in th e join t. Alth ough radiograph s are h elpful in excludin g fractures an d foreign bodies, the specific diagnosis of septic arthritis is m ade via joint aspiration . WBC count greater than 75,000, with neutrophils m ore th an 75% is in dicative of a septic arthritis.

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Differential Diagnosis In flam m atory arth ritis can m im ic septic arth ritis but gen erally dem on strates lower WBC coun ts an d lower percen tages of n eutroph ils. Treatment O n ce th e diagn osis of septic arth ritis is m ade, th e treatm en t is irrigation an d debridem en t of th e join t, followed by lon g-term oral or intravenous an tibiotics. Th e one exception is septic arthritis caused by Neisseria gonorrhoeae, which can usually be treated non operatively by intraven ous ceftriaxone.

Osteomyelitis Pathophysiology O steom yelitis, or an in fection of th e bon e, is typically caused by an open fracture or by spread of infection from adjacen t sites. Th e risk of osteomyelitis is in creased in im m un ocomprom ised patien ts, especially th ose wh o h ave diabetes. Presentation/Physical Examination Patien ts usually present with pain, swelling, eryth em a, and possible drain age. In flam m atory m arkers, such as CRP level an d ESR, are elevated. Radiographic Findings/Special Studies In itial radiograph s are often n egative. However, after several weeks of osteomyelitis, radiograph s will dem on strate osteopen ia an d periosteal reaction . Sequestra, wh ich is dead bon e with surroun din g gran ulation tissue, an d in volucrum , wh ich is periosteal n ew bon e, can also be seen . When radiograph s are n egative, MRI and nuclear m edicin e studies are invaluable in m akin g the diagnosis. Differential Diagnosis Th e differen tial diagn osis for osteomyelitis in cludes septic arth ritis, crystallin e arth ropathy, traum a, an d deep soft tissue in fection . Treatment Antibiotics are the first lin e of treatm en t an d are contin ued for 4 to 6 weeks. If con servative treatm en t fails, an associated abscess is presen t, or n ecrotic bon e is seen , th en surgical debridem ent is required.

Bite Wounds Pathophysiology Both hum an and an im al bite wounds are a com m on source of in fection in th e h an d. Hum an bites usually occur durin g an altercation wh en on e person strikes an oth er person in

th e m outh . Th e resultin g woun d over th e MP join t is term ed a fight bite. The m ost com m on organ ism s foun d in th ese woun ds are S. aureus and Eikenella corrodens. An im al bite infections are usually secondary to Streptococcus, Pasteurella multocida, or S. aureus, but th ey can also be polym icrobial. Cat bites becom e in fected m ore often th an dog bites because cat teeth are sh arper an d th erefore able to in oculate bacteria deeper with in th e tissue.

Presentation/Physical Examination Patients usually present with a wound on the h and. If the patien t presen ts with a dorsal woun d over th e MP join t after an altercation, careful physical exam ination is warran ted to be sure th at th is figh t bite does n ot com m un icate with th e join t. Radiographic Findings/ Special Studies Radiograph s are n ecessary to screen for fractures an d foreign bodies, especially with figh t bites. Treatment Most inoculated wounds should be copiously irrigated, left open, and treated with broad-spectrum an tibiotics, such as ampicillin –sulbactam (Unasyn) or am oxicillin – clavulanate (Augm entin). If a wound is grossly infected or if the joint is infected, form al irrigation an d debridem ent sh ould be perform ed in th e operating room . Rabies prophylaxis sh ould be con sidered if th e in volved an im al was a bat, fox, skunk, raccoon, unknown dom estic anim al, or a dom estic an im al dem on stratin g features of rabies.

Necrotizing Fasciitis Pathophysiology Necrotizin g fasciitis is a rapidly progressive an d poten tially life-threatening in fection of th e soft tissues. It usually stem s from relatively m inor traum a to the extrem ity. The m ost com m on organism responsible is group A β -hem olytic streptococcus, but S. aureus an d an aerobes m ay be presen t. It is seen m ore com m on ly in diabetic patien ts. Presentation/Physical Examination Patients presen t with rapidly spreading, painful erythem a that is accompan ied by induration and swelling. Inflam m atory m arkers, such as CRP and ESR, and WBC count are usually extrem ely elevated. As th e in fection progresses, th e patien t m ay becom e h em odyn am ically un stable. Radiographic Findings/Special Studies Radiograph s will sh ow sign ifican t soft tissue swellin g an d poten tially subcutan eous air. If th e patien t is stable an d th e diagn osis is un clear, an MRI can be perform ed, wh ich will sh ow edem a and swellin g of the fascial planes.


Differential Diagnosis Th e prim ary differen tial diagn osis is cellulitis, wh ich presen ts with less severe symptom s, stable vitals sign s, slower disease course. Treatment Mortality rates of been described between 10% and 30%. Th erefore, early an d aggressive surgical debridem en t alon g with empiric, broad-spectrum an tibiotics is warran ted. Antibiotics m ust include coverage for gram -positive organism s (cephalosporins), gram -negative organism s (gentam icin), and anaerobes (penicillin). In the operating room , watery, foul-sm elling fluid (“dishwasher pus’’) is usually found along the fascial planes. Multiple debridem ents are usually required, an d amputation is occasion ally n ecessary. If th e lim b can be salvaged, soft tissue coverage is often even tually required.

Atypical Infections Besides com m on bacterial infections, atypical infections from mycobacterial species an d fungi can be seen in the hand.

CONGENITAL HAND DISORDERS Fortun ately, con gen ital h an d deform ities are relatively rare occurren ces. However, wh en th ey do arise, th ey can h ave devastatin g con sequen ces, both for ch ildren an d th eir fam ilies.

Embryology Th e em bryon ic developm en t of th e upper lim b occurs in a surprisingly consistent an d reproducible pattern . On rough ly day 26, th e upper lim b buds appear. At th is tim e, lim b growth is controlled by the apical epidermal ridge. All growth in th e lim bs proceeds from proxim al to distal. By day 33, prim itive arm s an d h an ds h ave form ed. At 6 weeks, ch ondrification of the bones has begun. By 8 weeks, apoptosis (program m ed cell death ) h as separated out th e in dividual fingers. Incidence and Etiology Upper extrem ity anom alies are present in approxim ately 1 out of every 626 live birth s. However, on ly 10% of th ese an om alies cause any significant functional or cosm etic deficit. Th e root cause of h alf of th ese con gen ital defects is unknown, wh ereas the rest are believed to be either genetic or environm en tal in etiology. Wh en an upper extrem ity congenital anom aly is en countered, it is important to evaluate th e ch ild for an om alies of oth er organ system s, such as cardiac, gastroin testin al, or ren al.

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Classification Swanson h as divided anom alies of the upper lim b into 7 m ajor categories, which are outlined below: I. II. III. IV. V. VI. VII.

Failure of form ation (e.g., am putation s) Failure of differen tiation (e.g., syn dactyly) Duplication (e.g., polydactyly) Un dergrowth Overgrowth Congenital constriction ring syndrom e Generalized skeletal abnorm alities

Goals and Timing of Treatment Th e ultim ate goal of treatm en t for upper extrem ity con gen ital an om alies is to m axim ize fun ction . Creation of a satisfactory grasp is tan tam ount to achievin g this goal. The secon dary aim is to restore n orm al aesth etic appearance. Th e paren ts of ch ildren with th ese an om alies simply desire th at th eir ch ildren be “n orm al’’an d h ope th e h an d surgeon can ach ieve th is surgically. However, th is is n ot always possible, an d it is im portant to be h on est with parents about th is reality from th e begin n in g. If possible, plan n ed surgical correction of any con gen ital upper extrem ity an om aly sh ould be un dertaken before age 4 to 5, which is when sch ool typically begins. A com plete discussion of all con gen ital h an d con dition s is beyond the scope of this text. Som e of the Swanson m ajor categories are discussed later, an d several specific con ditions are m entioned in Chapter 11 (“General an d Regional Problem s in Ch ildren ’’). Failure of Formation Failures of form ation can be eith er tran sverse or lon gitudin al. Tran sverse failures of form ation typically presen t as amputations. Th ey are seen m ost often in the proxim al forearm but can occur anywhere in th e upper extrem ity. The incidence is rough ly 1 in every 20,000 live births. Treatm ent is rarely surgical an d often in cludes fitting ch ildren for prosth eses at an age as youn g as 6 m onths to encourage use of th e lim b. Oth erwise, th ey m ay ign ore th e lim b due to lack of function. Longitudinal failure of form ation is also known as phocomelia (derived from th e Greek word for “seal’’), a term used to den ote lim bs with a flipper-like appearan ce due to absence of either the forearm or the hum erus. Patients with longitudinal deficien cies differ from those with tran sverse on es in th at th e form er h ave digital structures. Lon gitudin al deficien cies com e in th ree types: complete, proxim al, and distal. In complete deficiencies, the han d is attached directly to sh oulder. In proxim al deficien cies, th e h an d is attached to an abnorm al hum erus. Last, in distal deficien cies, th e h an d is attach ed to th e h um erus with n o in tervening forearm . Of h istorical note, phocom elia was seen in the 1960s in ch ildren whose m others ingested thalidom ide during pregnancy. The m ainstay of treatm ent for

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lon gitudin al deficien cies is n on operative. Lim b train in g sh ould begin at an early age.

side of th e h an d. Postaxial polydactyly refers to duplication of th e sm all fin ger.

Failure of Differentiation Failure of differen tiation occurs when the norm al m ech anism s of apoptosis are disrupted an d structures th at n orm ally are separate rem ain join ed. Syn dactyly is th e m ost represen tative con dition in wh ich digits fail to separate. Syn dactyly is discussed furth er in Ch apter 11.

RECOMMENDED READINGS

Duplication Duplication refers to th e presen ce of an extra structure in th e hand, usually a finger or a thum b. Preaxial duplication, or polydactyly, refers to duplication s of the thum b or the radial

Barron OA, Glickel S, Eaton R. Basal join t arth ritis of th e thum b. J Am Acad Orthop Surg. 2000;8:314 –323. Cranford CS, Ho JY, Kalainov DM, et al. Hartigan carpal tunnel syndrom e. J Am Acad Orthop Surg. 2007;15:537 –548. Freelan d AE, Geissler WB, Weiss APC. Operative treatm en t of com m on displaced an d unstable fractures of the h and. J Bone Joint Surg Am. 2001;83:928 –945. Gupta R, Bozentka D, Osterm an AL. Wrist arthroscopy: prin ciples and clinical application s. J Am Acad Orthop Surg. 2001;9:200 –209. Nan a A, Josh i A, Lich tm an DM. Platin g of th e distal radius. J Am Acad Orthop Surg. 2005;13:159 –171. Saldan a MJ. Trigger digits: diagn osis an d treatm en t. J Am Acad Orthop Surg. 2001;9:246 –252.

The Hip and Fem ur Neil P. Sheth J. Stu art Melvin R. Bru ce Heppen st all

16

Charles L. Nelson

INTRODUCTION Th e h ip join t is th e m ost proxim al join t of th e lower extrem ity and plays an integral role in gait an d balan ced locom otion. The hip is designed for strength and m obility, and thus the bony architecture, soft-tissue structures, and surrounding m usculature are geared toward conferring constraint an d joint stability while allowing for a m ultitude of m aneuvers and range of m otion (ROM). Path ologic processes affecting th e hip are com m on and include soft-tissue in juries such as labrum an d cartilage defects, bony in juries such as fractures about the acetabulum and fem ur, vascular insults such osteonecrosis of the fem oral head, and degen eration of th e join t as seen in post-traum atic arth ritis an d osteoarthritis (OA). Hip pathology has a significant impact on a patient’s m obility and thus m ay result in a significant degree of m orbidity and dysfun ction with out adequate treatm ent. Th is ch apter will focus on a brief overview of th e em bryology an d developm en t of th e h ip, th e osteology an d m usculature surrounding the h ip joint, contribution of the hip to lower extrem ity gait and biom echan ics, as well as a series of soft-tissue and bony path ologies with an em ph asis on clin ical diagn osis, radiograph ic diagn osis, an d indications for surgical treatm ent.

ANATOMY Embryology of the Hip Th e h ip is defin ed as a ball an d socket-type join t. Th e fem oral h ead is situated within the confin es of th e acetabulum th at con fers bony stability to th e join t. Th e structural acetabulum is a result of a fusion between three separate pelvic bon es: th e ilium , isch ium , an d pubis (Fig. 16.1). Th ese th ree bon es are con fluen t at th e tri-irradiate car-

tilage (Fig. 16.2), th e m edial acetabular growth plate, an d even tually fuse togeth er durin g skeletal m aturity to comprise the innom inate bone. Two innom inate bones alon g with th e in terven in g sacrum con stitute th e pelvis (Fig. 16.3). Norm al developm en t of th e acetabulum is depen den t upon adequate articulation with th e fem oral h ead. In scen arios where th e fem oral h ead is subluxated or dislocated, the acetabulum is unable to properly develop and a condition kn own as developm en tal dysplasia of th e h ip (DDH) results. Depen din g upon th e severity of th e dysplasia, th e patien t m ay be predisposed to early on set osteoarth ritis (OA) of th e h ip. Early diagn osis is param oun t an d m ay be treated with closed reduction an d castin g or open acetabular an d/or fem oral osteotomy, depen din g on patien t’s age (please see Ch apter 11 on Pediatric O rth opaedics).

Osteology of the Pelvis and Proximal Femur As m en tion ed earlier, th e pelvis is com posed of two in n om inate bones an d the in terven in g sacrum . Wh en evaluating each hem ipelvis, the ilium has two important anterior prom in en ces: th e an terior superior iliac spin e (ASIS) an d th e an terior in ferior iliac spin e (AIIS). Th e ASIS is th e origin of the in guinal ligam ent, sartorius m uscle and is the insertion of the tran sverse and internal oblique abdom in al m uscles. The AIIS is th e origin of th e direct head of th e rectus fem oris m uscle an d th e Y ligam en t of Bigelow (iliofem oral ligam ent). Th e fusion of the ilium and th e pubis results in an oth er an terior prom in en ce kn own as th e iliopectineal em inence. The iliopsoas m uscle traverses the groove between th is em in en ce an d th e AIIS. Posteriorly, th e posterior superior iliac spin e (PSIS) is a prom in en ce th at h as clin ical sign ifican ce as th e poin t of referred lum bosacral pain . Just posterior an d superior to th e acetabulum is th e greater sciatic n otch (Fig. 16.1).

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Figure 16.1 Hemipelvis depicting the three components of the innominate bone. (Reprinted with permission from Tile M, Helfet DL, Kellam JF. Fractures of the Pelvis and Acetabulum. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2003.)

Figure 16.2 Image of the tri-irradiate cartilage in a 4-year-old patient. (Reprinted with permission from Callaghan JJ, Rosenberg AG, Rubash HE. The Adult Hip. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2007.)

In gen eral, th e acetabulum is orien ted in 20 to 25 degrees of an teversion an d 45 degrees of abduction or in clin ation . Th e cen tral in ferior surface is devoid of cartilage an d com prises th e cotyloid fossa boun d by th e tran sverse acetabular ligam ent. Th ese landm arks are typically used for retractor placem en t an d as referen ce poin ts for acetabular ream in g durin g total h ip arth roplasty. In addition , a cartilagin ous rin g called th e labrum surroun ds th e in n er lin in g of th e acetabulum like a h orseshoe (Fig. 16.4). The purpose of th e labrum is to deepen th e acetabulum an d en h an ce th e stability con ferred by the bony arch itecture of th e acetabulum . Th e proxim al fem ur is composed of th e fem oral h ead, th e fem oral n eck, th e greater an d lesser troch an ters, an d th e fem oral sh aft. Th e fem oral n eck is furth er subdivided into regions, nam ely the subcapital, transverse cervical, and basicervical region s. Th e area between th e two troch an ters is nam ed th e in tertrochanteric region and is composed prim arily of cancellous bone. Th e nam ed regions and the bony architecture becom e important con siderations for the appropriate treatm en t of various h ip fractures on th e basis of location of th e fracture lin e. Structurally, th e fem oral n eck is an teverted approxim ately 12 to 15 degrees com pared with th e epicon dylar axis between th e m edial an d lateral fem oral condyles, and the average neck shaft angle is 127 degrees (Fig. 16.5). Th e proxim al fem ur exten din g from just distal to th e in tertroch an teric region to 5-cm distal to th e lesser troch an ter is nam ed the subtrochanteric region of the fem ur. The

Chapter 16: The Hip and Femur

Figure

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16.3 Anteroposterior

view of the pelvis demonstrating two innominate bones along with the sacrum comprising the pelvis. (Reprinted with permission from Tile M, Helfet DL, Kellam JF. Fractures of the Pelvis and Acetabulum. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2003.)

subtrochanteric region contains th e calcar fem orale th at exten ds from th e fem oral n eck to th e subtroch an teric region. This bony colum n is the stron gest part of the proxim al fem ur and is responsible for resisting varus rotational m om ents. Additionally, its integrity defines wh eth er a subtrochanteric fracture is con sidered stable or unstable (see details in section on traum atic in juries to th e h ip an d fem ur).

Soft-Tissue and Musculature Surrounding the Hip Joint Soft-tissue structures surroun din g th e h ip play a key role in its stability. These include capsular th ickenings surrounding the hip: (a) iliofem oral ligam ent (stron gest), (b) isch iofem oral ligam ent, and (c) pubofem oral ligam ent as well as th e labrum (Fig. 16.6). These soft-tissue structures,

in addition to th e bony anatomy of the acetabulum , m ake th e h ip a very stable join t wh en com pared with oth er ball and socket join ts such as th e glenohum eral joint. Th e m uscular sleeve surroun din g th e h ip adds additional dynam ic stability to the joint. The gluteus m edius and m inim us are considered the abductor complex that plays an im portan t role in both fun ction an d stability after total hip arth roplasty. A series of short external h ip rotators insert onto the posterior aspect of the greater trochanter. Th e piriform is m uscle in sertion is typically used as a lan dm ark during the posterior approach to the hip as well as a startin g poin t for an tegrade in tram edullary n ailin g of fem oral shaft fractures. The iliopsoas, the strongest hip flexor, in serts on to the lesser troch an ter an d m ay be involved in h ip flexion contractures. The gluteus m axim us, th e m ain h ip exten sor, surroun ds th e posterolateral aspect of th e h ip. Th e gluteus m axim us is just deep to th e ten sor fascia lata, wh ich is also com m on ly used as a lan dm ark durin g surgical exposure of th e h ip. Th e m edial an d posterior compartm en ts of th e th igh con tain a series of adductor and ham string m uscles th at originate from the pubic ram i and th e ischial tuberosity (Fig. 16.7).

APPLIED NEUROVASCULAR ANATOMY ABOUT THE HIP Greater and Lesser Sciatic Foramen

Figure 16.4 The labrum and transverse acetabular ligament

within the acetabulum. (Reprinted with permission from Callaghan JJ, Rosenberg AG, Rubash HE. The Adult Hip. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2007.)

Posteriorly, th e sacrospinous (from th e sacrum to the ischial spine) and sacrotuberous (from the sacrum to the ischial tuberosity) ligam en ts define the borders of the greater and lesser sciatic foram en or notches, respectively. The piriform is m uscle is a key landm ark with regards to all structures posterior to the hip join t. Using this m uscle as a referen ce, th e superior gluteal artery an d n erve lie superior to the piriform is. Th e followin g structures lie deep to the

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A

B Figure 16.5 (A) The normal neck-to-shaft angle (angle of inclination of the femoral neck to the

shaft in the frontal plane) is approximately 125 degrees. The condition in which this angle is less than 125 degrees is called coxa vara. If the angle is greater than 125 degrees, the condition is called coxa valga. (B) Top view of the left femur showing the angle of anteversion formed by the intersection of the long axis of the femoral head and the transverse axis of the femoral condyles. The angle averages approximately 12 degrees in adults. (Reprinted with permission from Nordin M, Frankel FH. Basic Biomechanics of the Musculoskeletal System. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2001.)

B

A

Figure 16.6 (A) Anterior and (B) Posterior views of the hip. Illustration of the three pericapsular hip ligaments. (Reprinted with permission from Callaghan JJ, Rosenberg AG, Rubash HE. The Adult Hip. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2007.)


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Figure 16.7 Origin and insertion of the major muscles surrounding the hip joint. (Reprinted with permission from Callaghan JJ, Rosenberg AG, Rubash HE. The Adult Hip. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2007.)

piriform is: (a) puden dal n erve, (b) n erve to obturator in tern us, (c) posterior fem oral cutan eous n erve, (d) sciatic nerve, (e) inferior gluteal nerve, and (f) nerve to quadratus fem oris. All of these structures, includin g the piriform is m uscle, exit the pelvis through the greater sciatic foram en. However, both the puden dal nerve and the n erve to th e obturator internus reenter the pelvis through the lesser sciatic foram en (Figs. 16.1 and 16.2). Clinically, the greater sciatic foram en or notch is a key landm ark for identifying th e location of th e superior gluteal artery. Inadverten t injury to th is artery in th is location durin g surgery m ay result in significant bleedin g and retraction of the dam aged artery into the pelvis, m aking hem ostasis difficult to achieve.

Both divisions of th e sciatic n erve travel down th e posterior compartm ent of th e thigh covered by the biceps fem oris m uscle. Th e tibial n erve division supplies in n ervation to th e h am strin g m uscles (sem im em bran osus, sem iten dinosus, lon g h ead of th e biceps fem oris, an d th e h am strin g portion of th e adductor m agn us), wh ile th e peron eal division on ly in n ervates th e sh ort h ead of th e biceps in th e posterior thigh compartm ent. The two divisions of the sciatic nerve form ally separate posterior to th e knee prior to travelin g down th e rem ain der of th e lower leg.

Sciatic Nerve

Th ere is a very rich vascular supply surroun din g th e h ip join t. At th e level of th e L4 vertebral body, th e aorta bran ch es in to th e com m on iliac arteries, wh ich in turn furth er divide in to th e in tern al an d extern al iliac vessels at th e level of th e S1 sacral body. Th e in tern al iliac artery h as several bran ch es in cluding the obturator, superior gluteal, inferior gluteal, and internal pudendal. An un derstanding of th ese n am ed bran ch es is importan t especially followin g traum atic pelvic fractures or when screws are n eeded for

Th e sciatic n erve is th e largest periph eral n erve in th e body, an d it is classified as a m ixed n erve, containing both m otor an d sensory componen ts. Th e nerve is composed of L4-S3 lum bosacral plexus nerve roots. The nerve is divided in to a tibial and a peroneal nerve division, with the peroneal division position ed laterally, m akin g it m ore susceptible to in jury durin g posterior surgical approach es to th e h ip.

Cruciate Anastomosis

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Figure 16.8 Illustration of arterial supply surrounding the hip joint. (Reprinted with permission from Clemente CD. Clemente’s. Anatomy Dissector. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2011.)

fixation of th e acetabular cup durin g total h ip arth roplasty (see section on total h ip arth roplasty). The external iliac artery passes beneath th e inguin al ligam en t to becom e th e fem oral artery. Th e fem oral artery gives rise to th e m edial an d lateral fem oral circum flex arteries as well as th e profun da fem oris artery th at bran ch es in to several perforatin g vessels. Th e cruciate an astom osis about th e h ip is a con fluen ce of th e descen din g bran ch of the in ferior gluteal artery, the ascending branch of the first perforator, an d th e tran sverse bran ch es of th e m edial an d lateral fem oral circum flex vessels. Th is an astom osis lies at the inferior m argin of the quadratus fem oris m uscle an d is often en coun tered durin g a posterior approach to th e h ip (Fig. 16.8).

Vascular Supply of the Femoral Head Th e dom in an ce of th e blood supply to th e fem oral h ead ch anges according to patient’s age. From birth to 4 years, the m ajor vascular supply to th e fem oral head is derived from both the m edial and lateral circum flex arteries. There is also a contribution from the artery of the ligam entum teres, a bran ch of th e obturator artery th at travels with in a ligam en t th at con n ects th e fem oral h ead to th e cotyloid fossa (Fig. 16.9). Beyon d 4 years of age, th e lateral fem oral circum flex artery as well as the artery of the ligam entum teres contribute little to the blood supply of the fem oral head. The m edial fem oral circum flex artery em erges as th e dom inant


Obturator artery

Femoral artery Medial and lateral circumflex arteries Profunda femoris artery Nutrient artery

659

pon en ts from gravity, body weigh t, an d m uscle forces actin g upon th e join t. In th e static ph ase of gait, durin g doublelim b support, th e join t reaction force is approxim ately 5/6 body weight. Durin g single-lim b stance, the joint reaction force across th e h ip can in crease up to th ree tim es body weigh t. Th e in crease seen durin g sin gle-lim b support is a result of an in creased m om en t gen erated by th e abductor complex, wh ich h elps to keep th e pelvis level. Durin g walkin g, th e join t reaction force can reach four tim es body weight. In the postoperative recovery phase, non –weigh tbearin g status still results in join t reaction forces across th e h ip in th e order of 1.5 to 1.8 tim es body weigh t, which is a result of h ip flexion (via th e iliopsoas m uscle) used to avoid lower extrem ity contact with the floor. The lowest join t reaction forces seen with am bulation occur wh en patien ts use touch -down weigh t-bearin g with th e foot flat on the floor to steady the operative lower extrem ity.

Figure 16.9 The vascular supply to the femoral head arises from

the medial and lateral circumflex vessels, which create a ring giving rise to the cervical vessels. A minor contribution comes from the obturator artery via the ligamentum teres. From Bucholz RW, MD and Heckman JD, MD. Rockwood & Green’s Fractures in Adults, 5th ed. Lippincott, Williams & Wilkins, 2001.

artery supplying th e fem oral h ead and does so through the posterosuperior an d posteroin ferior retin acular bran ch es. In th e adult, th e m edial fem oral circum flex con tin ues to be the m ajor vascular supply to th e fem oral head via the lateral epiphyseal artery (Fig. 16.10). Disruption of this blood supply is of concern in displaced fem oral neck fractures as well as piriform is en try fem oral n ails in pediatric patien ts due to th e in crease risk of fem oral h ead osteon ecrosis.

BIOMECHANICS OF THE HIP Gait Analysis Th e prim ary goal of th e lower extrem ity is to allow for en ergy efficien t am bulation . Gait an alysis con stitutes evaluation of the gait cycle that begins and ends with heel strike of th e sam e lim b. Th ere are two compon en ts of th e gait cycle: (a) stance and (b) swing. The foot is in contact with the ground durin g stance phase and is being propelled forward during the swing phase. The stan ce phase is approxim ately 60% of th e gait cycle. Both feet are in con tact (Fig. 16.11) with the ground durin g double-lim b support that comprises 20% of the total gait cycle. Norm al gait requires en ergy efficien t locom otion . Efficien cy is obtain ed through a level pelvis, which is m aintained by hip abductor complex contraction. For norm al am bulation to occur, the hip m ust be able to flex to 40 degrees an d rotate 10 degrees, both in tern ally an d extern ally.

Joint Reaction Forces Th e join t reaction force is defin ed as th e sum of all forces that cross the h ip joint. These forces are resolved into com -

PATIENT EVALUATION Clinical History Th e evaluation of a patien t presen tin g with h ip pain requires a th orough an d detailed h istory. Th is h istory is com plim en ted by physical exam in ation an d wh en n ecessary im aging studies, including plain radiographs, m agnetic reson an ce im agin g (MRI), an d com puted tom ography (CT). Several key elem en ts are in corporated in to obtain in g a th orough patien t h istory. Th e h istory sh ould first focus on th e exact location of th e pain . It is im portan t to determ in e wh eth er th e patien t suffers from poin t ten dern ess versus diffuse pain en circlin g th e h ip. Wh en possible, try to h ave th e patien t poin t with on e fin ger to th e location of m axim al discom fort. In tra-articular h ip pain typically m an ifests as groin pain with h ip RO M, wh ereas referred pain to th e h ip from th e lum bar spine presents as diffuse pain over th e PSIS an d buttock. Th igh pain typically is in dicative of eith er h ip or fem oral pathology, especially wh en th e patien t h as previously un dergon e total h ip arth roplasty. Next, th e tem poral n ature of th e pain sh ould be determ ined. What has been th e duration of this pain? Has the pain been th ere for 3 days, 2 weeks, or 1 year? Un derstan ding the chronicity of th e complaint is critical in assessin g wh eth er th e patien t is likely to n eed surgical in terven tion . Relating the onset of the pain to a specific event is also critical in determ inin g the etiology. If the patien ts state that th eir h ip pain started after a fall, it is im portan t to obtain details surroun din g th e even t to fin d a correlation between th e m ech an ism of in jury an d th e un derlyin g path ology. After un derstan din g th e even ts leadin g up to th e on set of h ip pain, h ave the patien t rate th e pain on a scale of 1 to 10 to objectively docum en t th e degree of pain . Ask the patient regarding rem itting and exacerbatin g factors associated with their pain —what m akes the pain worse and what m akes it better? Are there specific m otion s that recreate th e pain ? Is th e pain alleviated by th e use of any

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Orthopaedic Surgery: Principles of Diagnosis and Treatment Foveal artery Ascending branch LFC (extracapsular arterial ring)

Obturator artery

Subsynovial intracapsular arterial ring Ascending cervical arteries Medial femoral circumflex artery Descending branch LFC

Femoral artery Profunda femoris artery Lateral femoral circumflex artery Foveal artery

A

Subsynovial intracapsular arterial ring Ascending cervical arteries

P

Extracapsular arterial ring Retinacula of Weitbrecht

Medial femoral circumflex artery

Femoral artery Profunda femoris artery

First perforator

m odalities? With lon g-stan din g pain from a degen erative process such as OA, patien ts m ay presen t with pain from prolon ged sittin g an d pain with th e first few steps of am bulation . Patien ts sh ould be question ed regardin g th e requirem en t of pain m edication , use of an ti-in flam m atory m edication s, previous in terven tion s (e.g., aquatic th erapy), as well as previous issues with the involved hip (e.g., delay in am bulation as a ch ild, requirem en t of bracin g as a ch ild, or known history of developm ental dysplasia). The use of an assistive device (e.g., can e or walker) for am bulation sh ould be docum en ted as well as a patien t’s in ability to am bulate

Figure 16.10 Vascular anatomy of the

femoral head and neck. (Top) Anterior aspect. (Bottom) Posterior aspect. LFC: lateral femoral circumflex artery (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

for any length of tim e. Has the patien t been wh eelchairboun d over th e past 2 years? In form ation of th is n ature is importan t in determ ining the contribution of com orbidities (e.g., cerebrovascular accident) to the patient’s condition and its effect on potential surgical treatm en t. Attention sh ould also be given to the patient’s history of m edications (e.g., corticosteroids m ay lead to osteonecrosis) an d social h istory (EtOH abuse is also associated with osteon ecrosis). It is imperative to question th e patien t regardin g symptom s th at m ay indicate concom itant lum bar spin e involvem ent. Pain originating in the hip m ay radiate to the knee


Figure 16.11 Range of hip joint motion in the sagittal plane for 30 normal men during level walking, 1 gait cycle. The ranges of motion for the knee and ankle joints are shown for comparison. (Reprinted with permission from Nordin M, Frankel FH. Basic Biomechanics of the Musculoskeletal System. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2001.)

via the obturator n erve; however, pain originatin g from th e hip does not typically radiate below the tibial tubercle. Degen erative disc disease an d spin al/ foram in al sten osis m ay m anifest as radicular pain exten ding beyond the kn ee into the lower leg and foot or as dull pain in the buttock and posterior th igh . Patien ts m ay also com plain of subjective num bn ess, tingling and weakn ess in the lower extrem ity, inability to sit for long periods, or pain with valsalva m aneuvers (sneezing or coughin g). These signs an d symptom s are crucial for differentiatin g lum bar spine pathology from hip pathology. A detailed m edical history should be obtained to determ in e a h istory of deep ven ous th rom bosis (DVT), pulm on ary em bolus, pulm onary or cardiac disease, renal disease, im m un ocomprom ised, or recen t/ ch ron ic in fection. In addition, patients with arthritis are typically elderly an d m ay be on m edication s such as blood th in n ers for other diagnoses. Use of these m edications m ay be im portan t in th e tim in g of operative in terven tion .

Physical Examination Wh en con ductin g a physical exam in ation of th e pain ful hip, it is im portan t to em ploy a th orough system atic approach . Gait an alysis is th e m ost im portan t fun ction al evaluation of th e lower extrem ity. O bservin g a patien t walkin g into the office can reveal a great deal about the patient’s hip pathology an d overall function al capacity. Typically, patien ts with a pain ful h ip will spen d a sh orter tim e in stan ce ph ase on the involved lower extrem ity and lean over the affected hip when weight-bearing to reduce th e joint reaction forces. Th is type of gait is term ed as Trendelenburg gait an d m ay also be seen with a weak abductor complex.

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Th e m eth od by wh ich to con duct th e physical exam in ation of th e h ip follows th e sam e prin ciples used to exam in e any organ system . Th e exam in ation sh ould adh ere to th e following sequence: (a) inspection, (b) palpation, (c) active an d passive RO M, (d) m an ual m uscle/ stren gth testin g, (e) n eurologic exam in ation , (f) vascular exam in ation , an d (g) special tests based on th e differen tial diagn osis developed from th e h istory. To inspect the h ip properly, it is recom m ended to disrobe th e patien t. In spect th e h ip for eviden ce of any skin discoloration , abrasion s, ecchym osis, open woun ds, drain in g sin us tracts, swellin g, fluid collection (h em atom a or abscess), as well as any previous in cision s. Asym m etry existin g between h ips sh ould be n oted. In addition , use th e position s of th e ASIS to determ in e if pelvic obliquity exists an d th en assess for leg len gth discrepan cy. Bony palpation surroun din g th e h ip sh ould flow system atically from an terior to posterior. Th e an terior structures th at sh ould be palpated in clude th e ASIS, iliac crests, an d pubic tubercles. Next, atten tion sh ould be focused on the greater trochanters. The posterior edge of the greater troch an ter is relatively un covered an d is easily palpable in a th in patien t. Th is is th e region th at is typically pain ful in patien ts with troch an teric bursitis. Con tin uin g posteriorly, the PSIS an d the ischial tuberosities should be palpated. Patients with referred pain from th e lum bosacral spine typically are diffusely ten der across th e PSIS an d sacrum . Th e h ip ROM sh ould be docum en ted. Norm al h ip flexion an d exten sion are 130 an d 20 degrees, respectively, wh ile intern al and extern al rotation of th e hip is 30 and 70 degrees, respectively. Th ese m an euvers are best tested with th e patient in the supine position. In the lateral decubitus position (patient on their side), hip abduction and adduction can be tested an d typically dem on strate 40 an d 30 degrees, respectively. Passive ROM of the hip sh ould be correlated to pain; patients with osteonecrosis of th e hip typically m ain tain h ip ROM but h ave pain ful in tern al rotation . In addition , all h ip ROM m an euvers m ust be don e with stabilization of th e pelvis to avoid artificially inflated degrees of m otion . Th e n eurovascular exam in ation begin s with m an ual m uscle testin g. Muscle stren gth is graded on a scale from 0 to 5: 0 is complete absen ce of m uscle fun ction ; 1 dem on strates m uscle fasciculations without any lim b m ovem ent; 2 represents th e ability to fire th e m uscle an d m ove th e lim b, but n ot again st gravity; 3 allows firin g of th e m uscle an d m ovem en t of th e lim b, but again st gravity on ly; 4 is firin g of th e m uscle again st som e resistan ce—th is grade is subdivided into a 4− and 4+ on th e basis of th e degree of resistan ce th at th e patien t can coun ter; an d 5 is full m uscle function. In general, the lower extrem ity m uscles m ust n ot be able to be m an ually overcom e to be given a grade of 5. A detailed n eurologic exam in ation of th e en tire lower extrem ity as well as provocative spin e m an euvers sh ould be docum en ted. Fun ction of th e m ajor n am ed n erves (e.g., fem oral, tibial, deep, and superficial peron eal) should be

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tested. In addition , sen sation to ligh t touch sh ould be determ in ed in th e derm atom al distribution of th e lower extrem ity. Adetailed sen sory n eurologic exam in ation is m ore importan t in diabetic patien ts wh o m ay suffer from diabetic neuropathy. Every patient should also undergo a vascular exam ination th at starts with palpation of th e dorsalis pedis an d posterior tibial arteries. In patien ts wh o do n ot h ave palpable pulses, a form al vascular con sultation sh ould be ordered to determ in e th e vascular status of th e in volved lower extrem ity. Vascular com prom ise m ay im pede woun d h ealin g or m ay result in a vascular crisis in th e early postoperative period followin g an elective h ip procedure. While obtain in g a detailed h istory and perform ing a basic physical exam in ation , th e surgeon should form ulate a differen tial diagn osis. On th e basis of th is differen tial diagnosis, special tests are perform ed to recreate patien t sym ptom atology an d con firm a diagn osis prior to employin g im agin g m odalities. Patients suffering from long standing hip pain, especially pain secondary to OA, m ay present with a hip flexion contracture due to con tracture of soft-tissue structures surroun din g th e h ip join t. Th e an terior capsule, h ip capsule, is m ost frequen tly in volved, resultin g in decreased h ip exten sion . Th e Th om as test aids in diagn osin g th e presen ce of a h ip flexion con tracture. Th e patien t is placed supin e on th e exam in in g table wh ile m axim ally flexin g th e con tralateral h ip an d kn ee by brin gin g th e kn ee in toward th e ch est. As th e exam in er, m ake sure to place your h an ds on th e ASISto en sure th at th e pelvis is stable an d flat again st the exam ining table. If th ere is a flexion contracture about the hip, the involved extrem ity will not rest flat on the table (Fig. 16.12). If th e pelvis is n ot flat on th e table, patien ts m ay be able to reposition th eir pelvis an d in crease th e degree of lum bar lordosis to com pen sate an d dem on strate full extension of th e involved hip. Patients with a tight iliotibial (IT) band m ay also com plain of lateral h ip pain . Th e Ober’s test dem on strates th e

presen ce of a tigh t IT ban d. Th e patien t is placed in th e lateral decubitus position with the un involved hip down on th e table. Th e un in volved extrem ity is flexed at th e kn ee and hip. If the IT band is tight, the patient will be unable to adduct the in volved extrem ity to contact th e opposite extrem ity. Recen tly, th e diagn osis of fem oroacetabular im pin gem en t h as been popularized due to its association with early OA of th e h ip in patien ts with out developm en tal h ip dysplasia. It is hypoth esized th at an abn orm al an atom ic relation ship between the fem oral head and neck m ay lead to impingem ent between the proxim al fem ur and the acetabulum , resulting in early degenerative changes of the hip joint. Patien ts suspected to h ave fem oroacetabular im pin gem en t typically present with lim ited h ip ROM and often have a positive im pin gem en t test, depen din g on th e location of th e impin gem en t. Th e an teroin ferior im pin gem en t test is don e with th e patien t in a supin e position . Th e extrem ity is intern ally rotated while bein g passively flexed to 90 degrees an d adducted. Con tact between th e fem oral n eck an d the acetabular rim typically results in pain, especially if th ere is a cartilage lesion . Th is m an euver is sen sitive but not specific for fem oroacetabular impingem ent. Most intra-articular hip pathologic conditions will also illicit pain with this m an euver. Less com m only, patients m ay suffer from posteroinferior im pin gem en t. Th e patien t is supin e an d placed at th e edge of th e exam in in g table. With full h ip exten sion , th e h ip is extern ally rotated. A test is term ed positive if the patient experien ces groin pain due to im pin gem en t of th e fem oral n eck on th e posteroinferior acetabular rim .

Radiographic Evaluation Stan dard radiograph s used to evaluate a patien t with h ip pain in clude a stan ding AP pelvis (Fig. 16.13), and a standing AP of the in volved hip with the hip internally rotated 15 degrees. A frog leg lateral or shoot-through lateral of th e involved h ip should also be obtained. These views provide

Figure 16.12 Thomas’ test. After simultaneous flexion of both hips, each hip may be extended separately to record the arc from the horizontal to the femoral shaft. This indicated the degree of passive flexion contracture of the hip. (Adapted from Steinberg M. The Hip and its Disorders. Philadelphia, PA, WB Saunders, 1991.)

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C

A,B Figure 16.13 (A) AP radiograph of the left hemipelvis. (B) Diagram demonstrating the anatomic landmarks seen on the AP radiograph. (C) The major landmarks identified by various lines are as follows: diagonal dashes, the iliopectineal line (anterior column); straight dashes, the ilioischial line (posterior column); and solid line, the anterior lip of the acetabulum. The same identifying lines are used in Figures 16.14 and 16.15. (Used with permission from Tile M. Fractures of the Pelvis and Acetabulum. Baltimore, MD: Williams and Wilkins Co, 1984.)

inform ation useful in defining disease an d determ ining the location of a path ologic lesion. Additional radiographic views can aid in traum a scenarios to define th e exten t of injury. The faux profile view is a weight-bearin g, oblique AP radiograph with th e patient’s body rotated 60 degrees and the affected h ip closest to th e x-ray plate. Th is provides a weigh t-bearin g lateral view an d allows for assessm ent of anterior coverage and m easurem en t of th e anterior cen ter-edge angle. Judet views are 45-degree angled hem ipelvis radiographs that dem onstrate in jury to the pelvic ring. An obturator oblique view is obtained by tilting the involved hem ipelvis 45 degrees upwards an d m akin g th e obturator foram en perpen dicular to th e x-ray beam . Th is view h igh ligh ts th e an terior colum n of th e pelvis an d th e posterior wall of th e acetabulum (Figs. 16.14 an d 16.15). The obturator oblique view on th e in volved side also ren ders an iliac oblique view of the opposite hem ipelvis (tilting th e uninvolved hem ipelvis 45 degrees down wards). Th e iliac oblique view depicts th e posterior colum n of th e pelvis an d th e an terior wall of th e acetabulum . Additional inlet an d outlet views of pelvis can be obtain ed, wh ich provide in form ation about sacral in juries an d resulting translation of the hem ipelvis. Th e inlet view is taken as an AP pelvis with the x-ray beam angled 45 degrees caudad an d is ben eficial for determ in in g an terior an d posterior tran slation of th e h em ipelvis. An outlet view is taken as an AP pelvis with the x-ray beam angled 45 degrees ceph alad an d is ben eficial for determ in in g superior an d in ferior tran slation of th e h em ipelvis. Th e outlet

view ren ders a true AP view of th e sacrum an d allows th e sacral foram in a to be seen enface. (See detailed discussion of radiography an d pelvic fractures in Ch apter 10.) In gen eral, wh en en h an ced bony detail of th e pelvis an d proxim al fem ur is required, a CT scan is th e im agin g m odality of ch oice. CT of th e abdom en an d pelvis typically exten ds down to th e level of th e lesser troch an ters an d wh en don e with fin e cuts (1 m m section s), provides great detail of the h ip join t. CT scan s are often used in th e setting of acute traum a sin ce m ost patien ts wh o sustain blun t abdom in al in juries will h ave a CT of th e abdom en an d pelvis as part of their overall traum a evaluation. Im ages are obtained in the axial plan e but can be reform atted to in clude recon structed coronal and sagittal im ages or three-dim en sional im ages. In th e treatm en t of pelvic fractures, CT scan im agin g can be very useful in fully un derstan din g th e fracture pattern an d developin g a soun d preoperative plan . In th e outpatien t settin g, CTscan s are a powerful adjun ct to plain radiograph s wh en diagn osin g subtle subch on dral collapse in patients with osteonecrosis of the hip, determ inin g th e degree of bony destruction by tum ors about th e h ip, an d evaluatin g an arth ritic h ip with m in im al x-ray ch an ges. In patients wh o h ave un dergon e total h ip replacem ent and suffer from in stability, CT scans can help determ ine the version of th e acetabular com pon en t. CT often augm en ts in form ation derived from th e radiograph ic evaluation an d in certain circum stan ces can be in valuable in determ in in g a treatm en t plan . MRI in general is utilized for enhanced detail regardin g th e soft-tissue an atomy surroun din g th e h ip join t,

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A

B

C

D Figure 16.14 (A) Obturator oblique radiographic view of the left hemipelvis. (B) This view is taken

by elevating the affected hip 45 degrees to the horizontal by means of a wedge and directing the beam through the hip joint with a 15-degree upward tilt. (C) Diagram demonstrating the anatomy of the pelvis on the obturators oblique view. (D) Diagram demonstrating the important anatomic landmarks by various lines (described in Fig. 16.13). In this view, note particularly the pelvic brim, indicating the border of the anterior column and the posterior lip of the acetabulum. (Used with permission from Tile M. Fractures of the Pelvis and Acetabulum. Baltimore, MD: Williams and Wilkins Co, 1984.)


A

B

C

D

Figure 16.15 (A) Iliac oblique radiographic view of the left hemipelvis. This view is taken placing

the patient in 45 degrees of external rotation by elevating the uninjured side on a wedge, as shown in (B). (C) Diagram demonstrating the anatomic landmarks of the left hemipelvis on the iliac oblique view, further clarified in (D) by the various lines described in Figure 16.13. This best demonstrated the posterior column of the acetabulum. (Used with permission from Tile M. Fractures of the Pelvis and Acetabulum. Baltimore, MD: Williams and Wilkins Co, 1984.)

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especially th e labrum . Often , an MRI arth rogram will be don e to diagn ose a labral tear. For th is study, dye is in jected in to th e h ip prior to obtain in g th e MRI to disten d the joint revealing soft-tissue structures that are norm ally apposed. MRI is also utilized for dem on stratin g th e early stages of osteonecrosis of th e h ip wh ere plain radiograph s m ay n ot sh ow any abn orm alities. Rarely, MRI is in dicated as an adjun ct to plain radiograph s in determ in in g th e etiology of h ip pain th at is un clear followin g radiograph ic evaluation . O th er m odalities, such as bon e scan s an d positron em ission tom ography, are helpful in determ inin g the presen ce of m etastatic lesion s about th e pelvis an d proxim al fem ur as well as osteon ecrosis an d osteomyelitis. In patien ts wh o are likely to h ave an in fectious etiology as th e source of their h ip pain , hip aspiration un der sterile conditions m ay be in dicated. Th e fluid sh ould be sen t for gram stain , culture, an d sen sitivity. A sin gle aspiration is approxim ately 50% accurate in iden tifyin g a m icroorgan ism . A secon d aspiration in creases th e accuracy to 80% in determ in in g a bacterial source of in fection .

TRAUMATIC INJURIES TO THE HIP AND FEMUR Hip Dislocations Th e h ip is a ball an d socket join t with in h eren t bony stability th at requires a trem en dous am oun t force for dislocation . Th us, h ip dislocation s are typically th e result of h igh -en ergy traum a with associated fractures an d in juries bein g com m onplace. Given th e h igh -en ergy n ature of th ese in juries, un satisfactory outcom es m ay be an ticipated in up to h alf of th e patien ts. Factors such as dam age to articular cartilage, n erves, an d th e vascular supply to th e fem oral h ead at th e tim e of in jury are beyon d th e con trol of th e surgeon an d con tribute to th e developm en t of complication s such as post-traum atic arth ritis, n eurologic deficit, an d avascular n ecrosis (AVN). However, tim ely reduction alon g with appropriate treatm en t of associated fem oral h ead an d acetabular fractures often im proves outcom es.

Classification Hip dislocations are in itially classified as anterior or posterior according to the relationsh ip of the fem oral head to the acetabulum . Th ompson an d Epstein first proposed a classification system for both an terior an d posterior dislocation s an d in corporated associated fractures of th e fem oral h ead an d acetabulum (Table 16.1). Stewart an d Milford proposed a sim ilar classification sch em e th at in cluded postreduction stability. Both of th ese classification s h ave been com m only employed over th e years an d have been sh own to predict outcom e. More recen tly, Levin in troduced a compreh en sive classification system that is useful for both anterior an d pos-

TABLE 16.1

CLASSIFICATION SCHEMES FOR POSTERIOR HIP DISLOCATIONS Thompson and Epstein Type I Type II Type III Type IV Type V

Dislocation with or without minor fracture Dislocation with single large fracture of the posterior rim of the acetabulum Dislocation with comminuted fracture of the rim, with or without a large major fragment Dislocation with fracture of the acetabular floor Dislocation with fracture of the femoral head

Stewart and Milford Type I Type II Type III Type IV

Simple dislocation without fracture Dislocation with one or more rim fragments but with sufficient socket to ensure stability after reduction Dislocation with fracture of the rim producing gross instability Dislocation with fracture of the head or neck of the femur

terior h ip dislocation s (Table 16.2). Th is classification system attempts to guide treatm en t on th e basis of th e pre- an d postreduction physical fin din gs, associated fractures, an d diagn ostic in form ation gain ed from radiograph s as well as CT scan.

Mechanism of Injury Th e vast m ajority of h ip dislocation s are posterior an d occur secon dary to h igh-energy m echanism s such as m otor veh icle accidents. Th ey are due to a posteriorly directed force on a flexed kn ee. Th ese in juries are com m on ly referred to as “dashboard’’ injuries. Other com m on m echanism s in clude falls, pedestrians struck by autom obiles, and sports injuries. Th e position of th e h ip, th e direction of th e force vector, an d th e patien t’s an atomy will determ in e th e direction

TABLE 16.2

LEVIN’S CLASSIFICATION OF POSTERIOR AND ANTERIOR HIP DISLOCATIONS Type I Type II Type III Type IV Type V

No significant associated fractures; no clinical instability after concentric reduction Irreducible dislocation without significant femoral head or acetabular fractures (reduction must be attempted under general anesthesia) Unstable hip after reduction or incarcerated fragments of cartilage, labrum, or bone Associated acetabular fracture requiring reconstruction to restore hip stability or joint congruity Associated femoral head or femoral neck injury (fractures or impactions)

Reprinted with permission from Browner BD, Levine AM, Jupiter JB, et al. Skeletal Trauma: Expert Consult. 4th ed. Saunders, 2008.


of th e dislocation an d wh eth er an associated fracture occurs. More than 85% of hip dislocations are posterior. It has been shown that increasing degrees of adduction an d flexion at th e tim e of impact m ake pure dislocation m ore likely. Conversely, less hip adduction and flexion typically leads to fractures of the posterior wall of the acetabulum or sh ear fractures of th e fem oral h ead. Additionally, in creased fem oral anteversion h as been shown to decrease th e risk of posterior wall acetabular fracture in posterior dislocation s. Anterior dislocations occur m uch less frequently than posterior dislocation s. Th e h ip m ust be in a position of abduction an d extern al rotation at th e tim e of im pact, as is often th e case in m otorcycle acciden ts, for an an terior dislocation to occur. The degree of flexion of the hip determ ines if the fem oral head com es to rest in a suprapubic or obturator location . However, th is an atom ic distin ction does n ot affect treatm en t or outcom e. Associated fem oral head fractures occur m ore com m on ly in anterior dislocations and typically are impaction-type fractures.

Presentation Patients with h ip dislocations typically presen t with severe pain an d are un able to bear weigh t or m ove th e affected hip. They m ay also complain of num bn ess in the sciatic or fem oral nerve distributions. Often patients will have m ultiple injuries at presentation and m ay be obtunded or uncon scious. Physical Examination In itially, th e physical exam in ation sh ould be directed by th e guidelines of th e Advan ced Traum a and Life Support System . Followin g a th orough traum a evaluation , exam in ation of th e patien t sh ould begin with observation of th e position of th e lim b. Posterior h ip dislocation s cause th e lim b to be fixed in flexion , adduction , an d in tern al rotation . On th e con trary, m arked abduction and external rotation are eviden ce of an an terior dislocation . However, associated fractures of the fem oral neck or sh aft will obscure these findings. Because of th e typical dashboard m echanism causing m ost hip dislocations, associated injuries should be anticipated. In spection an d palpation m ust in clude th e spin e, pelvis, an d th e en tire in jured extrem ity. Close atten tion sh ould be given to exam in ation of th e knee as kn ee injuries, such as patella fractures, ligam en tous in juries, an d dislocations, are especially com m on (Table 16.3). Followin g careful in spection of th e in jured extrem ity, a detailed n eurovascular exam in ation sh ould en sue. Sciatic nerve injury occurs in up to 20% of posterior dislocation s, an d it is important to m ake the diagn osis prior to reduction. Pulses should be palpated an d compared with th e con tralateral extrem ity. Rarely, an an terior dislocation m ay lead to fem oral vessel comprom ise, wh ile posterior dislocations m ay have associated occult knee dislocations with injury to the popliteal artery. Th e n eurovascular exam ination should be repeated im m ediately after reduction of th e hip as the sciatic nerve can becom e incarcerated.

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TABLE 16.3

ORTHOPEDIC INJURIES COMMONLY ASSOCIATED WITH HIP DISLOCATION Pelvic ring injury Acetabular fractures Femoral head fractures Femoral neck fractures Femoral shaft fractures Patella fractures Ligamentous knee injuries Knee dislocation Foot and ankle fractures Spine injuries Sciatic and femoral nerve damage

Radiographic Examination Radiograph ic evaluation begin s with careful an d system atic inspection of the AP pelvis radiograph. In a posterior dislocation , th e affected fem oral h ead will appear sm aller th an th e un affected h ip, an d th ere will be loss of con gruen ce between th e fem oral h ead and acetabulum (Fig. 16.16). With anterior dislocations, the fem oral head will appear larger th an th e con tralateral fem oral h ead. Rotation can be assessed th rough inspection of the relative positions of the lesser trochanters. It is very important to clearly visualize th e fem oral n eck for eviden ce of fracture prior to attempted reduction . Fem oral h ead fractures, pelvic rin g in juries, an d acetabular fractures should also be noted. Followin g reduction , th e five stan dard views of th e pelvis (AP, in let, outlet, obturator oblique, an d iliac oblique) an d a CT scan sh ould be obtain ed. Th ese studies

Figure 16.16 Anteroposterior radiograph of the pelvis depict-

ing a right hip dislocation. Shenton’s line on the right is disrupted, and there is a small posterior wall acetabulum fracture. Note that the right femoral head appears smaller than the left.

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Figure 16.17 Computed tomography scan demonstrating a

fragment of bone interposed between the femoral head and posterior articular surface that requires removal (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

sh ould be carefully scrutinized as to the congruency of the fem oral head within th e acetabulum and to identify associated fractures and loose bodies (Fig. 16.17). If the hip is un able to be reduced, a CT scan an d Judet views sh ould be em ergen tly obtain ed prior to open reduction .

Special Tests Bone scan or MRI m ay reveal vascular ch anges associated with AVN of th e fem oral h ead prior to evidence on plain radiographs. Additionally, MRI m ay be useful in the diagnosis of a labral tear. However, th ese studies have no curren t role in th e acute m an agem en t of h ip dislocation s. Differential Diagnosis Th e differen tial diagn osis is lim ited an d in cludes fractures of th e pelvis, acetabulum , an d proxim al fem ur. Treatment Hip dislocation constitutes an orthopedic em ergen cy. Th e goal of in itial treatm en t is to ach ieve reduction of th e fem oral h ead within in 6 hours of the injury. AVN of th e fem oral h ead h as been reported to occur in up to 40% of dislocation s; h owever, sign ifican tly lower rates of AVN occur for h ips reduced with in 6 h ours of dislocation . Addition ally, prom pt reduction relieves pressure on th e sciatic nerve. In the absen ce of a concurren t fracture of the fem ur neck, closed reduction with con scious sedation or general an esth esia sh ould be attem pted. Closed reduction of a posterior dislocation is m ost often ach ieved with th e Allis

Figure 16.18 The Allis reduction technique for posterior

hip dislocations. (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

m ethod (Fig. 16.18). With the patient supine, th is m ethod applies in -lin e traction to th e fem ur while slowly flexing, adducting, and internally rotating the hip. An assistan t applies down ward pressure to th e ASIS to stabilize th e pelvis. Anterior dislocations m ay be reduced with the tractioncoun tertraction m ethod with lateral pressure applied to th e m edial thigh (Fig. 16.19). An audible and palpable clun k is often evident when the hip reduces. After reduction, it is important to assess the stability of the hip by taking th e h ip through a full ROM. In the absence


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TABLE 16.4

COMPLICATIONS OF HIP DISLOCATION Posttraumatic arthritis Avascular necrosis of the femoral head Sciatic nerve injury Heterotopic ossification Recurrent dislocation (rare) Femoral nerve injury (rare)

n ess an d adhesion s. However, extrem es in ROM should be avoided un til th e join t capsule h as fully h ealed.

Figure 16.19 Reduction of an anterior dislocation with traction–

countertraction and lateral pressure applied to the medial thigh. (Reprinted with permission from Bucholz RW, Heckman JD, CourtBrown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

of an acetabular or fem oral h ead fracture, th e h ip sh ould be quite stable. As m en tion ed previously, th e n eurovascular exam in ation sh ould be repeated an d a CT scan obtain ed to assess the congruen cy of reduction and identify associated fractures and loose bodies within the hip joint. O pen reduction is em ergen tly in dicated for irreducible hips an d sciatic nerve in juries caused by closed reduction . An irreducible hip m ay be due to soft-tissue entrapm ent or blockage by a bony fragm en t. If excessive delay is n ot an ticipated, Judet views and a CT scan should be obtained prior to open reduction in an effort to iden tify possible obstruction s to reduction . O n ce reduction of th e fem oral h ead is ach ieved, associated fractures of th e acetabulum or fem oral h ead, as well as incon gruent reductions and loose bodies, m ay be addressed in a n on em ergen t fash ion . However, for h ips th at con tinue to be unstable after reduction or contain intraarticular fragm ents, skeletal traction should be employed to decompress th e acetabulum as th e patien t awaits join t debridem en t or defin itive treatm en t of an acetabular or fem oral head fracture. Postreduction m anagem ent of a patient suffering a pure hip dislocation wh o underwen t reduction within 6 hours of dislocation sh ould begin with partial weigh t-bearin g. Full weigh t-bearin g typically becom es tolerable with in 2 to 4 weeks. For a h ip th at was reduced m ore th an 6 h ours after dislocation , 8 to 12 weeks of protected weigh t-bearin g m ay be con sidered due to th e sign ifican tly h igh er rate of AVN of the fem oral h ead and potential for collapse. When th ere is dislocation with an associated fracture, th e postreduction or postoperative regim en is variable an d is determ in ed by the associated fracture. Regardless of the tim e to reduction, early h ip m otion sh ould be en couraged to m in im ize stiff-

Complications Th e lon g-term outcom e of a h ip dislocation is variable and is often dependen t on the complications encountered (Table 16.4). Posttraum atic arthritis is th e m ost com m on com plication , occurrin g in up to 70% of cases. Its developm ent is likely m ultifactorial and m ay be related to cartilage dam age at th e tim e of in jury, th ird body wear, or m alreduction of associated fractures. AVN of the fem oral head is a dreaded complication wh ose in ciden ce is dim in ish ed with em ergen t reduction . However, it m ay still occur in up to 10% of patien ts despite reduction within 6 hours of the injury. Its developm ent is believed to be prim arily related to ischem ia induced by kin kin g an d spasm of th e ascen din g cervical an d circum flex fem oral vessels. Th us, reduction is th ough t to relieve vasospasm allowin g for resumption of perfusion to th e fem oral h ead. Sciatic n erve in jury m ay complicate up to 20% of posterior dislocation s an d can lead to severe fun ction al deficits. Th e in jury is typically in complete with th e peron eal division of the nerve m ost com m only affected. Recovery of n erve fun ction is often unpredictable an d m ay be evaluated at 3 m onths with an electromyogram (EMG). Heterotopic ossification is not uncom m on after open reduction of a posterior h ip dislocation an d is m ore com m only associated with an anterior approach . Prophylaxis with in dom eth acin or radiation m ay reduce th e developm ent of clinically significant heterotopic ossification.

Femoral Head Fractures Fem oral head fractures are relatively rare in juries that are typically due to severe traum a to the hip joint. In fact, nearly all fem oral h ead fractures are associated with a hip dislocation . Th e h igh -en ergy n ature, as well as th e frequen cy of associated in juries an d com plication s, h as h istorically led to relatively poor function al outcom es. More recen tly, improved surgical techniques and understanding of the relevan t an atom y h ave im proved our ability to treat th ese in juries.

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A B

C

D Figure 16.20 The Pipkin’s classification of femoral head fractures. (A) Type I—fracture inferior

to the fovea. (B) Type II—fracture superior to the fovea. (C) Type III—femoral head fracture with associated fracture of the femoral neck. (D) Type IV—femoral head fracture with associated fracture of the acetabular rim. (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Classification Th e m ost com m on ly utilized classification sch em e is proposed by Pipkin (Fig. 16.20). Th is relatively sim ple classification system is useful for com m un ication an d correlates with progn osis. Type I and Type II fractures are distin guish ed by th e location of th e fracture lin e in relation to the fovea. In Type I fractures, th e fracture line is in ferior to the fovea, while in Type II fractures, the fracture extends superior to th e fovea into the weigh t-bearing portion of the fem oral h ead. Th is important distinction often directs treatm en t an d correlates with outcom e as Type I fractures typically perform better th an Type II fractures. As on e m igh t expect, fem oral h ead fractures with an associated fracture

of th e fem oral n eck (Type III fracture) h ave th e worst progn osis overall. Brum beck et al. an d Th e Orth opaedic Traum a Association have each proposed m ore comprehensive classification system s that apply to both an terior an d posterior dislocations. Th ese classification system s also h ave prognostic value but have not gained widespread use in clinical practice.

Mechanism of Injury As stated previously, nearly all fem oral head fractures are due to traum atic h ip dislocation s. As such, fem oral h ead fractures are typically secon dary to h igh -energy


m echanism s such as m otor vehicle accidents, pedestrians struck by autom obiles, falls, an d sports in juries. Th e direction of h ip dislocation an d th e position of the hip at the tim e of impact determ ine the presence an d type of facture. Classically, fem oral head fractures are caused by posterior hip dislocations. However, on ly approxim ately 15% of posterior dislocation s h ave an associated fracture of the fem oral head. Nevertheless, when these fractures occur, typically a portion of the head is sh eared off by th e acetabular rim as the head dislocates. Th is m ay leave a portion of th e h ead with in th e acetabulum an d block closed reduction attempts. In con trast, anterior dislocation s com m only result in inden tationtype fractures as the fem oral h ead is levered out of th e acetabulum .

Presentation Patients with fem oral head fractures usually have an accompanying hip dislocation. They will present with severe pain with inability to m ove the affected hip or bear weigh t. Th ey m ay also com plain of n um bn ess in th e sciatic or fem oral nerve distribution s. Often patients will have m ultiple injuries at presentation and m ay be obtunded or un con scious. Physical Examination Th e physical exam in ation sh ould in itially be directed by th e guidelines of th e Advan ced Traum a and Life Support System . Followin g a th orough traum a evaluation , exam in ation of th e in jured extrem ity sh ould begin with observation of the position of the lim b as this will give clues to the direction of the hip dislocation an d the potential type of fem oral head fracture present. Posterior hip dislocations cause th e

671

lim b to be fixed in flexion , adduction , an d in tern al rotation . On th e con trary, m arked abduction an d extern al rotation are eviden ce of an an terior dislocation . However, with a fem oral head fracture or associated fracture of the fem ur or acetabulum , these signs m ay n ot be present. In spection an d palpation should include th e en tire extrem ity with emph asis on exam in ation of the knee as these in juries are com m on with posterior h ip dislocation s. Addition ally, a careful n eurovascular exam in ation sh ould be perform ed an d repeated after h ip reduction .

Radiographic Examination Evaluation begin s with careful an d system atic review of th e AP pelvis radiograph (Fig. 16.21A). Dislocation is typically apparent with disruption of Sh enton ’s line and incongruen cy between th e fem oral h ead an d acetabulum . Often th e fractured portion of the fem oral head will rem ain in the acetabulum , h eld th ere by an in tact ligam en tum teres. Furth er inspection m ay reveal associated fractures of the acetabulum and fem oral neck. Followin g closed reduction or in th e even t of an irreducible dislocation , th e five stan dard views of th e pelvis (AP, inlet, outlet, obturator oblique, an d iliac oblique) and a CT scan sh ould be obtain ed. Th ese studies will allow for the assessm ent of the con gruency of reduction as well as identify in tra-articular loose bodies and associated fractures (Fig. 16.21B). Additionally, the CT scan will accurately localize the fracture plane in the fem oral head, which is useful in plan n in g th e surgical approach . Special Tests Bon e scan or MRI m ay reveal vascular ch an ges associated with AVN of th e fem oral h ead prior to eviden ce on plain

A

B Figure 16.21 (A) Anteroposterior radiograph of the pelvis depicting a posterior hip dislocation

with femoral head fracture. Note the portion of the femoral head remaining within the acetabulum (arrow) and the fracture of the posterior wall of the acetabulum (arrow head). (B) Coronal CT reconstruction in the same patient.

672


radiographs but have no current role in the acute m an agem en t of fem oral h ead fractures.

injury, heterotopic ossification, and th e treatm ent of associated fractures.

Differential Diagnosis Th e differen tial diagn osis is lim ited an d in cludes fractures of th e pelvis, acetabulum , an d proxim al fem ur.

Femoral Neck Fractures

Treatment Hip dislocation with fem oral h ead fracture is an orth opedic em ergen cy. Th e goal of in itial treatm en t is to ach ieve reduction of th e fem oral h ead with in 6 h ours of th e in jury as th is h as been sh own to decrease th e rate of AVN. O ccasion ally, a h ip dislocation with fem oral h ead fracture is irreducible. Often th is is due to th e blockage by fem oral head fracture fragm ents. In this case, em ergent open reduction is in dicated. If a substan tial delay is n ot an ticipated, a CT scan sh ould be obtain ed prior to open reduction to accurately iden tify th e fracture fragm en ts an d aid in operative plan n in g. O n ce reduction of th e fem oral h ead is ach ieved, defin itive m an agem en t of th e fem oral h ead fracture depen ds on a n um ber of variables in cludin g th e stability of th e h ip reduction , size of th e fragm en t, location of th e fracture in relation sh ip to th e weigh t-bearin g surface, an d th e quality of fracture reduction . Non surgical m an agem en t sh ould be considered for dislocation s in which a congruent an d stable reduction is ach ieved with associated fractures th at h ave less th an 2 m m of step off or do n ot in volve th e weigh tbearin g portion of th e fem oral h ead. Surgical treatm en t is in dicated for fem oral h ead fractures in wh ich th e h ip rem ain s un stable or in con gruen t, in tra-articular loose bodies are en trapped in th e join t or fracture reduction that is nonanatom ic. Simple excision is appropriate for loose bodies or fracture fragm en ts th at are com m inuted or do not involve th e weigh t-bearing portion of th e fem oral h ead. Large fracture fragm en ts, especially those th at involve the superior weigh t-bearing dom e of the fem oral h ead, sh ould undergo open reduction with stable in tern al fixation . For fractures m an aged n on operatively or with open reduction an d in tern al fixation , weigh t-bearin g is typically protected for 8 weeks to en sure fracture h ealin g. For th ose fractures in which fragm ents are simply excised, full weightbearin g m ay begin wh en tolerated. Regardless of treatm en t, early h ip m otion sh ould be en couraged to m in im ize stiffness and adhesions. However, extrem es in ROM sh ould be avoided un til the join t capsule has fully h ealed. Outcomes and Complications Historically, fem oral head fractures have resulted in relatively poor fun ction al outcom es. Modern surgical tech niques and em ergent hip reduction have led to som ewhat improved results. However, as with h ip dislocation s, th e overall outcom e from a fem oral h ead fracture is often depen den t on th e com plication s en coun tered such as posttraum atic arth ritis, AVN of th e fem oral h ead, sciatic n erve

Fem oral n eck fractures are in tracapsular fractures occurrin g between th e articular surface of th e fem oral h ead an d th e intertrochanteric region of the proxim al fem ur. These fractures occur in two distinct populations. In the elderly, th ese are com m on injuries typically due to low-en ergy falls and h ave associated 1-year m ortality rates of 14% to 50%. Addition ally, in elderly patien ts, it h as been reported th at on ly about half of the patien ts will regain their prefracture functional status. Much less com m only, these fractures occur in young patients and are generally secondary to high-energy traum a. In eith er case, a fracture of th e fem oral neck can be a devastating injury with an impact th at reaches far beyond the fracture itself.

Classification Fem oral n eck fractures are often classified accordin g to th e an atom ic location of th e fracture lin e. Th is includes basicervical fractures occurring at the base of the neck, transcervical fractures th rough the m id-portion of th e neck, and subcapital fractures at th e base of the h ead. However, it is often difficult to precisely defin e th e exact location of th e fracture line with plain radiography, and thus, this classification m eth od h as lim ited utility. Th e m ost com m on ly used classification sch em e is th at proposed by Garden (Fig. 16.22). Th is classification system is based on the degree of displacem en t observed on plain radiograph s. Garden I fractures are in com plete or impacted. Garden II fractures are complete fractures with out displacem en t. Garden III fractures are complete fractures with partial displacem en t, while Garden IVfractures are completely displaced. However, distin ction between Garden I an d II or between Garden III an d IV does n ot affect treatm en t. Th us, there has been a trend toward simply classifying these fractures as nondisplaced or displaced since this improves both interobserver an d intraobserver reliability and has greater relevan ce to treatm en t an d progn osis. Fem oral n eck fractures h ave also been classified by Pauwel according to th e angle at which the fracture line m akes with the h orizon tal (Fig. 16.23). Type I fractures are 30 degrees from th e h orizon tal; Type II, 50 degrees from th e h orizon tal; and Type III, 70 degrees from th e h orizontal. Th is classification was based on th e hypoth esis th at vertically oriented fracture lin es are m ore unstable and lead to greater complication s. However, furth er research h as dem on strated th at it is often difficult to accurately m easure the angle of the fracture on prereduction radiographs and that the fracture angle does not correlate with nonun ion or AVN. Th us, this classification is not com m only used today. Additionally, th e Orthopaedic Traum a Association h as proposed a compreh en sive classification system . Th is


A

673

Garden type I

Figure 16.22 The Garden classification of femoral neck fractures. (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

B

classification schem e is based on fracture location an d displacem en t an d is m ost useful for research purposes.

Mechanism of Injury In th e elderly, a fracture of th e fem oral n eck is alm ost always an insufficiency fracture through osteoporotic bone. Th e m ech an ism m ay be a low-en ergy fall directly on to th e greater troch an ter causin g in im paction fracture or an extern al rotation force th at causes th e fem oral n eck to lever an d buckle off of th e posterior acetabulum , leading to com m inution of the posterior neck. In youn ger patien ts, h igh -en ergy traum a, such as a m otor veh icle acciden t or a fall from a h eigh t, is usually required to gen erate a fracture of th e fem oral n eck. Typically, the m echanism is an axial force along the fem oral shaft

Garden type II

that m ay include a rotation al component. This m echanism causes high Pauwel angle shear-type fractures and contributes to th e association between fractures of th e fem oral sh aft an d con curren t fracture of the fem oral neck in youn g patien ts.

Presentation Th e clin ical presen tation of a patien t with a fem oral n eck fracture can vary widely. Patients generally present with groin pain an d an in ability to bear weigh t; h owever, stress fractures and nondisplaced fractures m ay present with no obvious clin ical deform ity an d on ly sligh t groin pain . Typically, there is noticeable shortening an d external rotation of th e in volved extrem ity. Elderly patien ts wh o live alon e m ay be discovered hours to days after a fall and present with

674


C

Garden type III

D

Garden type IV

dehydration , decubitus ulcers, or con fusion . With elderly patien ts, it is im portan t to in quire about th e patien t’s prior functional level and the circum stances that lead to the fall. In youn ger patien ts, because of th e h igh -en ergy n ature of these injuries, there m ay be associated injuries as well as signs an d symptom s of shock.

Physical Examination For h igh -en ergy m ech an ism s an d obtun ded elderly patien ts, th e in itial exam in ation sh ould be directed by th e

Figure 16.22 (continued)

guidelines of the Advanced Traum a an d Life Support System . Followin g a th orough traum a evaluation , exam in ation of th e in jured extrem ity sh ould begin with close in spection of th e skin for sign s of an open fracture. Sh orten in g an d extern al rotation of th e affected leg sh ould be n oted. ROM of th e h ip sh ould be avoided as it m ay lead to furth er fracture displacem ent. In high-en ergy m echanism s, a detailed exam in ation of th e en tire in jured extrem ity is im portan t with special atten tion to th e exam in ation of th e kn ee. Elderly patien ts sh ould be evaluated for con com itan t fragility

Chapter 16: The Hip and Femur Type I

Type II 30˚

50˚

675

Type III 70˚

Figure 16.23 The Pauwels’ classification of

femoral neck fractures. (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

fractures such as distal radius an d proxim al hum erus fractures. While nerve or vessel injury is uncom m on, a careful neurovascular exam ination should be perform ed in all patien ts.

Radiographic Examination Radiograph ic evaluation begin s with careful scrutiny of th e AP pelvis radiograph as well as the AP and cross-table lateral views of the affected hip. An AP view of the h ip in 10 to 15 degrees of intern al rotation is often h elpful as it offsets the fem oral anteversion and provides a true AP of the fem oral n eck. Fracture displacem ent, the degree of osteoporosis, an d presen ce of posterior com m in ution sh ould be noted as these factors will affect the treatm ent. Reduction can be assessed radiograph ically via two m ethods. Lowell described the radiographic appearance of th e fem oral h ead –neck junction (Fig. 16.24). An atom ic alignm ent sh ould reveal the convex fem oral head m eeting the concave fem oral neck, thus form ing an S-curve on both of th e visualized cortices. Malreduction will cause a Csh aped curve on one cortex and a sh arp apex on the oth er. A second m ethod of assessing reduction is th rough th e Garden Alignm ent In dex (Fig. 16.25). Th is m ethod m ea-

A

sures th e an gle form ed between the bony trabeculae of the fem oral neck an d the fem oral head fragm ent on both the AP and lateral radiographs. In the AP plane, th e norm al align m en t is 160 degrees. On the lateral radiograph, n orm ally th e trabeculae form a straigh t lin e (180 degrees). A Garden Align m ent Index of 155 to 180 degrees on both AP an d lateral radiograph s in dicates an acceptable reduction .

Special Tests MRI and bone scan are helpful in diagnosing stress fractures or occult n on displaced fem oral n eck fractures for th ose patients with groin pain and inconclusive radiographs. Bone scan sh ould be delayed until 48 hours post injury to decrease th e rate of false n egatives; h owever, MRI will reveal fractures im m ediately. Additionally, MRI is appropriate for suspected path ologic fractures. While CT scans can be used to confirm a fem oral n eck fracture, they are not adequate to rule out a nondisplaced fracture and therefore have m inim al utility in the assessm ent of th ese patients. Differential Diagnosis Th e differen tial diagn osis in cludes in tertroch an teric fem ur fracture, fractures of the pubic ram i, acetabular fracture,

B

Figure 16.24 (A) The cortices of an anatomically reduced femoral neck fracture will from an S- or

reverse S-shaped curve on both radiographic views. (B) Malreduction will cause a C-shaped curve on one side and a sharp apex on the opposite. (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

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160°

140° 180°

150°

(AP)

(Lat)

sacral insufficiency fracture, OA, AVN, tum or, or lum bar spin e pathology.

Treatment Fractures of th e fem oral n eck are best treated with operative m an agem en t th at allows for early m obilization an d full weight-bearing. Because of the significant m orbidity an d risks associated with prolon ged recum ben cy, n on operative treatm en t sh ould on ly be con sidered in patien ts wh o are extrem ely poor surgical can didates or in n on am bulatory patien ts wh o h ave m in im al discom fort. In eith er case, early bed-to-ch air m obilization sh ould be in stituted with knowledge that m alunion will occur. In elderly patien ts, the presence of fracture displacem en t, preexistin g OA, an d th e fun ction al dem an ds of th e patien t are im portan t factors in determ in in g th e appropriate m eth od of surgical treatm en t. Fracture displacem en t has important implication s regarding th e viability of the fem oral head. In nondisplaced fractures, rates of AVN have been reported to be 13% to 20%, compared with rates as high as 25% to 40% for displaced fractures. This discrepan cy is believed to be due to differin g degrees of dam age to th e ascen din g cervical vessels. Th ese vessels travel with in the joint capsule to supply a large portion of the fem oral head and are thought to partially rem ain in tact in n ondisplaced fractures. Th us, n on displaced fractures (Garden I an d II) are gen erally treated with an atom ic reduction an d in tern al fixation utilizin g parallel lag screws with th e expectation of low rates of fem oral h ead collapse from AVN (Fig. 16.26). O n th e oth er h an d, displaced fractures (Garden III an d IV) are typically treated with prosth etic replacem en t due to th e h igh probability of fem oral h ead n ecrosis an d subsequen t collapse. Prosthetic replacem ent m ay con sist of hem iarthroplasty in which a fem oral stem with a m etallic h ead is used to replace th e fem oral h ead an d n eck (Fig. 16.27). Altern atively, a total h ip arth roplasty m ay be used, in wh ich th e acetabulum is resurfaced in addition to pros-

Figure

16.25 The Garden Alignment Index.

Anatomic (black) and nonanatomic reductions (blue) are depicted. (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

th etic replacem en t of th e fem oral h ead an d n eck. Th e decision to em ploy a h em iarth roplasty versus a total h ip arth roplasty is depen den t on th e presen ce of preexistin g h ip pain , th e degree of OA with in th e acetabulum , an d th e activity level of the patient. Preexisting hip pain, significant degen erative ch an ges with in th e acetabulum , or a h igh ly active patien t would likely lead to progressive acetabular erosion and pain with hem iarthroplasty. In these cases, total hip arth roplasty is often th e preferred option. However, the

Figure 16.26 Anteroposterior radiograph of the hip demon-

strating anatomic fixation of a femoral neck fracture with three parallel lag screws.


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TABLE 16.5

COMPLICATIONS OF FEMORAL NECK FRACTURES Nonunion Malunion Failure of internal fixation Avascular necrosis of the femoral head Pain Deep venous thrombosis Infection Heterotopic ossification Dislocation Death

tients due to dim inished functional capacity and upper extrem ity weakness. In younger patients, weight-bearin g status will depend on the stability of the reduction but if often delayed for 6 weeks.

Figure 16.27 Anteroposterior radiograph of the hip, depicting a modular hemiarthroplasty in good position.

longer operative tim e, increased blood loss, an d increased risk of postoperative dislocation m ust be con sidered on a case-by-case basis when choosing between total hip arthroplasty an d h em iarth roplasty in th e m an agem en t of fem oral neck fractures. In con trast to elderly patien ts, fem oral n eck fractures in young patients are orthopedic em ergencies. All attempts to save the patient’s n ative fem oral head an d reduce th e rate of AVN sh ould be m ade th rough em ergen t reduction an d stabilization within 6 hours of th e in jury. For displaced fractures, a single attempt at closed reduction should be m ade in the operating room , and if successful, percutaneous pinnin g should en sue. However, m ore com m on ly closed reduction is un successful, and the surgeon should proceed with open reduction to ach ieve an atom ic align m en t. A detailed un derstanding of the vascular anatomy is required to m in im ize furth er dam age to th e fem oral h ead blood supply durin g th e surgical approach . On ce reduction is obtained, the fracture should be rigidly stabilized with cancellous lag screws or a slidin g screw and side-plate with a derotational screw. Postoperatively, patients are m obilized im m ediately. It has been shown th at the elderly will self-regulate weightbearin g an d th us sh ould be allowed to weigh t bear as tolerated in m ost in stan ces, wh eth er th ey un dergo prosth etic replacem en t or in tern al fixation , as th is prom otes early m obilization . Th is is an im portan t poin t to con sider as partial an d n onweight bearing are often not possible in elderly pa-

Complications Treatm ent of fem oral neck fractures m ay be complicated by loss of fixation, non un ion, m alunion, pain, dislocation, deep vein throm bosis, infection, AVN, and death (Table 16.5). Early fixation failure is uncom m on an d is associated with fracture com m inution and varus reduction. The rates of non un ion and AVN are related to fracture displacem ent with h igh er rates occurring for displaced fractures. Historically, nonunion rates for nondisplaced fractures have ranged from 0% to 5%, while nonunion rates as h igh as 35% h ave been reported for displaced fractures. However, rates of n onunion appear to be im provin g with m odern treatm en t m eth ods. More recen tly, n on union rates in youn g patien ts are typically less than 10% an d are likely related to im proved fixation an d tim ely surgical treatm ent. AVN with collapse complicates 11% of n on displaced fractures an d up to 27% of displaced fractures.

Intertrochanteric Hip Fractures In tertroch an teric fem ur fractures are extracapsular fractures th at occur in th e tran sition al region between th e base of th e fem oral n eck an d th e lesser troch an ter. Th is region is m ade up of dense trabecular bone an d includes the calcar fem orale, which is the strut of dense bon e between the posterom edial fem oral n eck an d sh aft th at acts to tran sfer stress from th e fem oral n eck to the fem oral shaft. Wh ile differen t from fem oral n eck fractures an atom ically an d in th e way in wh ich th ey are m an aged, th e epidem iology of in tertroch an teric an d fem oral n eck fractures is quite sim ilar. Intertroch anteric fractures also occur in two distin ct patien t population s. Th e vast m ajority of th ese fractures occur in the elderly and are fragility fractures from low-en ergy m echanism s. In the elderly population, these

678

A


B

Figure 16.28 The Evans’ classification of in-

C

D

E

in juries can be devastatin g with an impact th at reach es far beyon d th e fracture itself. It h as been reported th at on ly approxim ately h alf of th e patien ts will regain th eir prefracture functional status, while 1-year m ortality rates have ranged from 14% to 50%. Much less com m only, these fractures occur in young patients and are typically secondary to highen ergy traum a.

Classification Historically, in tertrochanteric fractures h ave been classified accordin g to th e system in troduced by Evan s (Fig. 16.28). Evan s recogn ized th at th e posterom edial cortex was the key to fracture stability. Subsequently, he divided intertroch an teric fractures in to two groups (stable an d un stable) on the basis of the integrity of the posterom edial cortex. In stable fractures, the posterom edial cortex is intact or h as m in im al com m in ution . Un stable fractures h ave a com m inuted posterom edial cortex or have a reverse obliquity fracture pattern . Evan s recogn ized th at reverse obliquity fractures are in h eren tly un stable with a ten den cy toward m edial m igration of the fem oral sh aft. He also n oted that som e unstable fractures can be converted to stable fractures through restoration of th e posterom edial cortex. Th is fracture classification is importan t n ot on ly because it defin es th e stability of th e fracture but because it also guides treatm en t th rough defin ition of a stable reduction . However, despite th e importan t con tribution s of th is classification , it h as been plagued by poor in terobserver reliability. Th us, today th e un derlyin g prin ciples of th e Evan s’ classification are utilized to facilitate com m un ication an d guide treatm en t by simply describin g in tertroch an teric fractures as stable or un stable.

tertrochanteric hip fractures. (A) Stable with intact posteromedial cortex. (B) Stable with minimal comminution of posteromedial cortex. (C) Unstable with comminuted posteromedial cortex. (D) Unstable with global comminution. (E) Unstable with reverse obliquity fracture pattern. (Reprinted with permission from Bucholz RW, Heckman JD, CourtBrown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Mechanism of Injury Th e vast m ajority of in tertroch an teric fractures are fragility fractures in the elderly secondary to low-energy m echan ism s. Approxim ately 90% result from a sim ple fall, m ost often directly on to th e lateral h ip wh ere th ere is little soft tissue to cushion th e blow. In younger patients, h igh-en ergy traum a is required to fracture the intertrochanteric region of th e fem ur. Motor veh icle acciden ts or a fall from a h eigh t causin g a direct blow to th e lateral hip or a rotational force to th e leg are th e m ost com m on m ech an ism s. Presentation Th e clin ical presen tation of an in tertroch an teric fracture can vary widely. Patients with displaced fractures will com plain of severe groin pain an d will be un able to stan d or bear weigh t. However, som e n on displaced fractures will cause slight groin pain and will lack th e typical sh ortened an d externally rotated posture present in displaced fractures. Thus, th e diagnosis of a hip fracture should be con sidered for any patient complaining of groin pain. Elderly patien ts wh o live alon e m ay be discovered h ours to days after a fall and m ay present with dehydration , decubitus ulcers, or con fusion . In youn ger patien ts, th ere m ay be associated injuries as well as signs and symptom s of shock. Physical Examination For h igh -en ergy m ech an ism s an d obtun ded elderly patients, the initial exam ination should be directed by the guidelines of th e Advan ced Traum a and Life Support System . Followin g a th orough traum a evaluation , exam in ation of th e in jured extrem ity sh ould begin with close in spection of the skin for sign s of open fracture. Shortening an d


679

extern al rotation of th e affected leg sh ould be n oted. ROM of th e h ip sh ould be avoided as it m ay lead to furth er fracture displacem ent. In h igh -energy m echanism s, a detailed exam in ation of th e en tire in jured extrem ity is im portan t with special atten tion given to th e exam in ation of th e kn ee. As with fem oral neck fractures, the elderly should be evaluated for con com itant fragility fractures such as distal radius an d proxim al hum erus fractures. While neurovascular injury is un com m on , a careful n eurovascular exam in ation sh ould be perform ed in all th e patients.

Radiographic Findings Radiograph ic evaluation begin s with careful scrutiny of th e AP pelvis radiograph as well as the AP and cross-table lateral views of th e affected h ip. An AP view of th e h ip in 10 to 15 degrees of intern al rotation is often helpful as it offsets the fem oral anteversion and provides a true AP of th e proxim al fem ur. Fracture displacem ent, the degree of osteoporosis, and presence of posterom edial com m in ution should be noted as th ese factors will affect th e treatm en t. Radiographs of th e con tralateral h ip m ay be h elpful for preoperative plan n in g. Special Tests In patien ts with groin pain an d in con clusive radiograph s, MRI and bone scan are helpful in diagnosing occult n on displaced fractures of th e proxim al fem ur. Bon e scan sh ould be delayed un til 48 h ours post in jury to decrease th e rate of false n egatives; h owever, MRI will reveal fractures im m ediately. Addition ally, MRI is appropriate for suspected path ologic fractures. Differential Diagnosis Th e differen tial diagn osis in cludes fem oral n eck fracture, fractures of the pubic ram i, acetabular fracture, sacral insufficien cy fracture, OA, AVN, tum or, or lum bar spine path ology. Treatment In tertroch an teric fem ur fractures are best treated with operative m an agem en t th at provides for early m obilization an d full weigh t-bearing. Because of the significant m orbidity and risks associated with prolon ged recum ben cy, nonoperative treatm en t sh ould on ly be con sidered in patien ts wh o are extrem ely poor surgical can didates or in n on am bulatory patien ts wh o h ave m in im al discom fort. In eith er case, early bed-to-chair m obilization sh ould be instituted with kn owledge th at m alun ion will occur. Today, in tertroch an teric fem ur fractures are typically treated with either a sliding screw plate device or a ceph alom edullary device that incorporates a lag screw into the fem oral head through an intram edullary nail. The appropriate ch oice of implan t depen ds on th e fracture pattern an d stability. Cephalom edullary devices have gen erally been foun d to be m ost appropriate for very un stable fractures and reverse obliquity pattern s. Regardless of the

Figure 16.29 Anteroposterior radiograph of the hip, demonstrating the use of a sliding screw plate device.

device used, successful operative treatm en t begin s with adequate reduction. Accurate reduction will restore th e biom ech an ics of th e h ip an d lessen th e load on th e im plan t. Reduction sh ould restore th e fem oral n eck-sh aft an gle and correct rotational deform ity. Large posterom edial fragm ents sh ould be reduced and secured with a cerclage wire or in terfragm en tary screw to improve th e stability of th e fracture. Th e m ost com m on m eth od of treatin g in tertroch an teric fractures is with a sliding screw plate device (Fig. 16.29). Th is device allows for con trolled fracture impaction th rough slidin g of th e lag screw with in th e barrel of th e side-plate. Th e fracture impaction provided by this device prom otes h ealin g an d decreases th e stress on th e im plan t th rough a reduction in th e m om en t arm actin g on th e lag screw. An im portan t factor in preventing superior cutout of th e lag screw is placem en t of th e screw with in 1 cm of subch ondral bon e an d in the center of the fem oral head. Measurem ent of the tip –apex distan ce, defin ed as th e sum of distan ces from th e tip of th e screw to th e apex of th e fem oral head on both the AP and lateral radiographs, predicts th e rate of screw cutout (Fig. 16.30). In creasin g rates of cutout h ave been associated with tip –apex values greater th an 25 m m . O verall, slidin g screw plate devices h ave h ad th e h igh est success rates; h owever, th ey sh ould be avoided in reverse obliquity fracture pattern s or very unstable fractures with subtrochan teric exten sion due to high failure rates.

680


Tip apex distance

X ap D true = known diameter of the lag screw

TAD = (X ap x

D D true ) + ( X lat x true D lat D ap

)

Dap D lat

Figure 16.30 Illustration of the tip–apex

X lat

Recen tly, ceph alom edullary devices with a slidin g lag screw h ave risen in popularity (Fig. 16.31). These devices offer som e theoretical advantages over the sliding screw plate devices. It is believed th at ceph alom edullary devices reduce the lever arm acting on the lag screw. Additionally, the intram edullary im plan t m ay buttress again st excessive lateral translation of th e proxim al fragm en t durin g com pression . Moreover, newer m aterials an d designs have decreased the inciden ce of fracture at the tip of the nail, which plagued the first generation of these devices. Of note, the tip –apex m easurem en t also applies to these devices when placing

distance. (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

the lag screw. Despite these theoretical advan tages, studies have shown that there is no difference in the outcom e compared with the sliding screw plate devices for m ost intertrochanteric fractures; however, m ore frequent com plication s h ave been reported with th e ceph alom edullary n ails. Treatm en t of h igh ly un stable fracture pattern s sh ould be approach ed m ore cautiously and are worth special m en tion. Th ese fracture patterns in clude highly com m inuted fractures, fractures with subtrochanteric exten sion, an d the reverse obliquity fracture. O ften occurrin g in youn ger patients secondary to high-energy traum a, these fractures are n otorious for excessive collapse, n on un ion , an d implan t failure, especially wh en a slidin g screw plate device is em ployed. Th us, h igh ly un stable fractures are best treated with long cephalom edullary implan ts. Postoperatively, patients should be m obilized im m ediately. It has been shown that the elderly will self-regulate weigh t-bearin g an d th us sh ould be allowed to weigh t bear as tolerated in m ost instances to prom ote early m obilization. In youn ger patients, weight-bearing status will depen d on th e stability of th e reduction .

Complications Treatm ent of in tertrochanteric fractures is m ost com m only complicated by loss of fixation and lag screw cutout, occurrin g in up to 20% of cases. Close atten tion to th e tip –apex distan ce an d avoidin g th e use of th e slidin g screw plate device for highly un stable fracture patterns should m inim ize these complications. Because of the extracapsular location of th ese fractures an d th e rich vascular supply, n on un ion occurs in less th an 2% of th ese fractures. Fin ally, careful scrutiny of th e reduction is necessary to avoid rotational m alunion.

Subtrochanteric Femur Fractures Figure 16.31 Anteroposterior radiograph of the hip, demonstrating the use of a long cephalomedullary device.

Subtroch an teric fractures occur in a zon e exten din g from the lesser trochan ter to 5 cm distal to the lesser trochanter;


however, proxim al involvem en t of the in tertrochanteric region is not uncom m on. The m edial an d posterom edial cortices of the subtrochanteric fem ur experience the highest compressive stresses in the body, while the lateral cortex is under a high degree of tensile stress. The action of the iliopsoas, the h ip abductors (gluteus m edius an d gluteus m inim us), and short external rotators cause the proxim al fragm ent to flex, abduct, and externally rotate, respectively, wh ile th e pull of th e adductors lead th e distal fragm en t to adduct (Fig. 16.32). Because of th ese powerful m uscle forces and th e trem en dous stresses on the bone, fracture reduction an d m ain ten an ce of th e reduction can be quite ch allenging.

Classification Num erous classification sch em es h ave been proposed for subtrochanteric fractures. Th e Fielding’s classification is an an atom ic classification based on the distance of the m ajor fracture lin e from th e lesser trochanter an d is rarely used today. Th e Sein sh eim er’s classification factors in th e in tegrity of th e posterom edial cortex to predict fracture stability

681

(Fig. 16.33). This classification guides treatm ent, predicts outcom e, an d is th e m ost clin ically useful. Th e Russell–Taylor’s classification is based on the integrity of th e piriform is fossa (Fig. 16.34). In th is system , Type I fractures h ave an in tact piriform is fossa, wh ile Type II fractures h ave a fracture lin e exten din g in to th e piriform is fossa. These are subclassified as either A or B depending on th e presen ce of posterom edial com m in ution . Th is classification was design ed to guide th e treatm en t of th ese fractures with a piriform is entry intram edullary nail. However, th is classification is less im portan t today due to th e im provem en t in in tram edullary tech n iques an d th e m ultitude of devices with extrapiriform is fossa en try poin ts. Additionally, the O TA and AO h ave offered descriptive classification system s on th e basis of th e fracture con figuration. These classification schem es are quite comprehensive and thus, typically too cum bersom e for routine clinical use.

Mechanism of Injury In youn g patien ts, subtroch an teric fractures are typically th e result of h igh -en ergy blun t traum a or gun sh ot woun ds. A low-en ergy m ech an ism in a youn g patien t sh ould raise th e suspicion of a path ologic fracture. In th e elderly, th ese fractures typically occur through osteoporotic bone after a low-en ergy fall. Rarely, a subtroch an teric fracture m ay result from treatm en t of a fem oral n eck fracture with can n ulated screws. If th e startin g poin t for th e screws on the lateral fem oral cortex is distal to the lesser trochanter, a stress riser is created and there is a risk of fracture. Presentation Patien ts typically presen t un able to am bulate due to sign ificant pain. Typically, there is obvious shortening and extern al rotation of the leg with m arked swellin g of th e proxim al th igh . As th ese fractures are often secon dary to h igh -en ergy traum a, the patient m ay presen t with associated injuries as well as sign s an d sym ptom s of sh ock. Physical Examination In itially, th e physical exam in ation sh ould be directed by th e guidelin es of th e Advan ced Traum a an d Life Support System as these are often high-energy fractures and m ay h ave associated in juries. Followin g a th orough traum a evaluation , exam in ation of th e in jured extrem ity sh ould begin with close in spection of th e skin for sign s of open fracture. Th e en tire lim b sh ould th en be in spected an d palpated for eviden ce of ipsilateral extrem ity traum a. Careful atten tion sh ould be given to th e kn ee for signs of effusion, which m ay be in dicative of ligam en tous in jury. Alth ough n eurovascular injuries are rare with subtroch anteric fem ur fractures, a detailed n eurovascular exam in ation sh ould be perform ed.

Figure 16.32 Drawing depicting the deforming forces acting on

a subtrochanteric femur fracture. (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Radiographic Examination Radiograph ic evaluation in volves detailed an d system atic review of th e AP radiograph of th e pelvis as well as an

682


Type II A

B

C

1 1

1

2 2

2

Type III A

B

1

1

2 2 3

3

Type IV

Type V

1

2

3 4

in tern al rotation AP view an d cross-table lateral view of the affected hip and entire fem ur.

Special Tests Plain radiograph s are typically sufficien t for diagn osis an d preoperative plan n in g; h owever, MRI is in dicated if th ere is con cern for path ologic fracture. Differential Diagnosis Th e differen tial diagn osis is lim ited an d in cludes h ip dislocation, fem oral neck fracture, and peritrochanteric fracture. Treatment Subtroch an teric fem ur fractures are best treated with surgical fixation. Because of the significant m orbidity and risks associated with prolon ged recum ben cy, n on operative treatm en t sh ould on ly be con sidered for patien ts wh o are ex-

Figure 16.33 The Seinsheimer’s classification of subtrochanteric femur fractures. Type I (not shown)—nondisplaced. Type II—two-part fracture. Type III—three-part fractures. Type IV—comminuted. Type V—subtrochanteric fracture with intertrochanteric extension. (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

trem ely poor surgical candidates. In the rare in stance that n onoperative treatm ent is deem ed appropriate, th e patient sh ould be placed in 90 to 90 skeletal traction for 8 to 12 weeks followed by h ip spica castin g. With 90 to 90 skeletal traction , th e h ip is h eld in a 90-degree flexed position and allowed to externally rotate in an attempt to bring th e distal fragm en t in -lin e with th e flexed an d extern ally rotated proxim al fragm en t, th us m in im izin g m alun ion . Wh ile th e surgical tech n iques an d implan ts for th e treatm ent of subtrochanteric fem ur fractures have evolved, the goals of ach ieving stability while restoring length, alignm ent, and rotation to allow rapid m obilization have rem ained th e sam e. Historically, treatm ent of these fractures involved open reduction and the application of rigid intern al fixation with plates, a slidin g h ip screw device, or blade plate. Because of size an d stren gth of th e im plan ts required to control the powerful m uscle forces inherent to th ese


683

I-B I-A

II-A

II-B

Figure 16.34 The Russell–Taylor’s classification of subtrochanteric fractures. (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

fractures, large dissections and soft-tissue stripping were typically necessary. This contributed to high rates of delayed union, nonun ion, and ultim ately to implan t failure. With advan ces in m odern in tern al fixation prin ciples an d implan ts, closed reduction tech n iques h ave allowed for near an atom ic reductions without disturbing th e fracture hem atom a or further dam aging th e local blood supply. However, closed reduction rem ains a dem an din g tech n ique, an d careful atten tion is required to avoid varus alignm ent, shorten ing, or rotational m alunion. Following closed reduction, an interlocking an tegrade intram edullary device is em ployed percutan eously to stabilize th e fracture (Fig. 16.35). Use of an intram edullary device affords two additional advantages over traditional platin g techniques by decreasing the m om ent arm on the implan t through its intram edullary location and supplying local bone graft from the ream ing required for canal preparation . Fractures with m in im al com m in ution , an in tact posterom edial cortex, an d with out proxim al exten sion m ay be treated with a first gen eration in tram edullary n ail. For com m in uted fractures or th ose with extension into the intertrochanteric region , a ceph alom edullary n ail offers superior fixation . Occasion ally, closed reduction is un able to be achieved. In these cases, a lim ited open reduction with m in im al softtissue dissection should be perform ed with consideration of bon e graftin g th e posterom edial cortex. Postoperatively, the patient’s weight-bearing should be restricted un til m ature callus is n oted on radiograph s an d

the patient’s pain has subsided. Often these fractures require 8 to 12 weeks for h ealin g. Failure of th e fracture to un ite m ay be related to in fection , th e n utrition al state of th e patien t, com orbid h ealth con dition s, exten sive soft-tissue strippin g, or in adequate fixation.

Femoral Shaft Fractures Fractures of the fem oral shaft occur in the portion of th e diaphysis from 5 cm distal to th e lesser troch an ter to 5 cm proxim al to the adductor tubercle. The fem ur is th e stron gest bon e in th e body an d th erefore typically requires a h igh -en ergy m ech an ism to fracture. Because of th e h igh -en ergy n ature of th ese fractures, associated in juries are com m on . Addition ally, th e excellen t vascularity an d sizable m uscular compartm ents surroundin g the fem ur can lead to sign ificant blood loss requiring transfusion in n early half of th e patien ts. However, th is sign ifican t soft-tissue coverage an d vascularity also con tributes to th e low rate of n on union . Advan ces in traum a resuscitation as well as surgical techniques have greatly improved the m orbidity and m ortality associated with th ese injuries.

Classification Often for inform al com m unication, these fractures are classified descriptively on th e basis of the location (proxim al, m iddle, or distal third) and fracture m orphology (transverse, oblique, spiral, com m inuted, or segm en tal).

684


A

B Figure 16.35 (A) Subtrochanteric femur fracture. (B) Anatomic stabilization with a cephalomedullary device.

Win quist an d Han sen offered a m ore form al classification schem e that is also com m on ly employed (Fig. 16.36). It was designed to predict which fractures would be prone to sh orten in g, an d th us require treatm en t with an in terlocked n ail, o th e basis of th e am oun t of fracture com m in u-

tion. Today, it is rare to consider the treatm ent with an in tram edullary nail without employing in terlockin g screws. Neverth eless, th is classification sch em e rem ain s useful, h as progn ostic sign ifican ce, an d aids in operative plan n in g. Addition ally, a com preh en sive classification proposed by th e

Figure 16.36 The Winquist–Hansen’s clas-

0

I

II

III

IV

sification for femoral shaft fractures. (A) No comminution. (B) Small butterfly fragment with minimal comminution. (C) Large butterfly fragment with at least 50% cortical contact remaining. (D) Large butterfly fragment with less than 50% cortical contact remaining. (E) Comminution with no cortical contact remaining. (Reprinted with permission from Bucholz RW, Heckman JD, Court-Brown CM, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)


685

AO/ Orth opaedic Traum a Association exists an d is typically utilized for research purposes.

Mechanism of Injury Fem oral sh aft fractures are alm ost always due to h igh en ergy m ech an ism s such as m otor veh icle acciden ts, falls, gunsh ots, or pedestrian injuries. Pathologic fracture should be suspected for any patien t presen tin g with a fem oral sh aft fracture in the absence of high-energy traum a. Sin ce th e fem oral sh aft is essen tially a cylin der, th e exact m ech anism of injury can often be extrapolated from the fracture pattern. Transverse fractures are the result of a ben din g force. Torque applied to th e fem ur causes a spiral fracture. An elem en t of compression com bin ed with a ben din g force creates an oblique fracture or a butterfly fragm en t. For com m inuted fractures, it is th e degree of energy an d not the direction of force that determ ines th is pattern. Presentation Typically, th ese patien ts presen t un able to am bulate, in a trem endous am ount of pain and with obvious deform ity of th e th igh . In cases of associated traum a, patien ts m ay presen t obtun ded, un con scious, or in sh ock. Physical Examination Th e in itial physical exam in ation sh ould be directed by th e guidelines of th e Advan ced Traum a and Life Support System as th ese are often h igh -en ergy fracture an d m ay h ave associated in juries. Even in isolated fractures of the fem oral shaft, blood loss of greater th an 2.0 L into the th igh can be significant and results in hem odynam ic instability. Followin g a th orough traum a evaluation , exam in ation of th e in jured extrem ity sh ould begin with close in spection of the skin for signs of open fracture. Next, the en tire lim b should be inspected and palpated for evidence of ipsilateral extrem ity traum a. Careful attention should be paid to th e kn ee for sign s of effusion , wh ich m ay be in dicative of ligam en tous in jury or fracture. A detailed n eurovascular exam in ation m ust be perform ed in each patien t wh o h as sustain ed a fem ur fracture. Finally, th e compartm en ts of the thigh should be assessed for evidence of compartm ent syn drom e, and if warranted, form al compartm ent pressure m easurem en t should be un dertaken. Radiographic Examination Radiograph ic assessm en t sh ould begin with careful evaluation of full-length AP and lateral views of th e fem ur for fracture pattern, bon e quality, and length (Fig. 16.37). Fulllength radiographs of the contralateral fem ur are useful in com m in uted fractures for assessing the patient’s norm al len gth and an atom ic bow. Alternatively, a CT scout view that includes both fem urs m ay give useful inform ation on fem oral length. Measurem en t of th e size of the fem oral can al will guide preoperative planning for the intram edullary n ail diam eter. Additionally, it is imperative to carefully scrutinize high-quality internal rotation AP and lateral views of the ipsilateral hip for eviden ce of fem oral

Figure 16.37 Anteroposterior radiograph of midshaft femur fracture.

n eck fracture. Concom itan t fem oral n eck fractures occur in up to 10% of fem oral sh aft fractures an d are often subtle and nondisplaced. AP pelvis as well as AP and lateral radiograph s of th e kn ee sh ould also be obtain ed an d carefully reviewed for associated in juries.

Special Tests MRI is indicated for evaluation of suspected path ologic fractures. Differential Diagnosis Th e differen tial diagn osis is lim ited an d in cludes oth er fractures of the fem ur. Treatment Th e in itial goal of th e treatm en t for fem oral sh aft fractures is to expeditiously restore length, alignm en t, and rotation. Skeletal traction an d external fixation are frequently used for this purpose in a temporary capacity. They serve to alleviate pain and m inim ize bleeding through a reduction in the volum e of the thigh. Today, however, skeletal traction and extern al fixation have lim ited utility as defin itive treatm ent of fem oral shaft fractures due to frequent m alun ion , pin site in fection , an d kn ee stiffn ess. Addition ally, skeletal traction requires prolon ged recum ben cy leading to increased pulm onary complications an d greater risk of decubitus ulcers. Th us, th ese m eth ods sh ould on ly be con sidered as defin itive stabilization in patien ts wh o are extrem ely poor surgical can didates.

686


A

B

Figure 16.38 Anteroposterior radiographs of intramedullary nail fixation of midshaft femur fracture (A & B).

The goals of definitive treatm en t are to restore len gth, alignm ent, and rotation wh ile providing stable fixation that allows early m obilization. Additionally, the tim in g of fixation is importan t. It h as been dem on strated th at early defin itive fixation of fem oral sh aft fractures with in 24 h ours of th e in jury, in th e absen ce of severe ch est traum a or head in jury, sign ifican tly decreases th e in ciden ce of pulm on ary complications including acute respiratory distress syndrom e. Defin itive fracture stabilization in th e vast m ajority of fem oral shaft fractures, including m ost open fractures, is best ach ieved with an in tram edullary n ail (Fig. 16.38). Th ese devices provide for early m obilization an d are in serted into the intram edullary canal at a site rem ote from the fracture. In closed in juries, th is allows the fracture hem atom a to rem ain un disturbed, which h as beneficial effects on fracture h ealin g. Intram edullary n ails are load sharing devices th at act as intern al splints. The load supported by th e nail depends on th e stability of th e fracture, with gradual load tran sfer to the fem ur as th e fracture heals. In terlockin g screws should be used in n early all cases an d serve to m ain tain rotation an d length. Typically, intram edullary n ails are inserted in an antegrade fash ion from the piriform is fossa or greater troch an ter. However, th e n ail m ay be in serted in retrograde m anner through a knee arthrotomy. This technique m ay be useful in floatin g kn ees, bilateral fem oral fractures, extrem e obesity, an d pregn an t patien ts.

In tram edullary n ails m ay be in serted with or with out ream in g. Ream in g allows for in sertion of a larger diam eter n ail an d provides bon e graft at th e fracture site; h owever, it disrupts th e en dosteal blood supply. Despite its effects on th e en dosteal blood supply, ream in g h as been sh own to decrease th e rate of delayed un ion an d n on un ion for fem oral sh aft fractures. Alth ough th e m ajority of fem oral sh aft fractures are best treated with in tram edullary n ailin g, fixation with a plate an d screws rem ain s a viable option . Plate fixation also provides for early m obilization ; h owever, th e exten sive dissection n ecessary for in sertion of the plate as well as th e load-bearin g n ature of th ese devices are distin ct disadvan tages compared with in tram edullary n ailin g. Plates rem ain a poten tial treatm en t altern ative for fem oral sh aft fractures with an associated fracture of th e fem oral neck as well as for fractures occurring at th e distal m etaphyseal– diaphyseal jun ction . Percutan eous in sertion tech n iques m ay broaden th e in dication s for plate fixation in th e future. Postoperatively, patients should be m obilized im m ediately to dim in ish th e risk of pulm on ary com plication s an d pressure sores. Un restricted active an d passive m otion of th e kn ee sh ould be en couraged. Weigh t-bearin g often depen ds on associated in juries. However, in an isolated fracture of the fem oral sh aft, regardless of com m inution, m odern large diam eter-ream ed in tram edullary n ails with two distal in terlockin g screws allow for im m ediate weigh t


bearin g as tolerated. Com plication s are relatively in frequen t an d in clude in fection , n on un ion , m alun ion , device failure, an d th igh compartm en t syn drom e.

ATRAUMATIC HIP CONDITIONS Hip Arthritis OA, also kn own as degen erative join t disease, is th e m ost prevalen t form of arth ritis affectin g th e m ajor join ts of th e lower extrem ity (e.g., hip an d kn ee). Long-standing arthritis eventually results in end-stage joint deterioration and serves as a leading cause of physical disability worldwide. It is estim ated that th at approxim ately 16 m illion people in the United States suffer from OA and 1 in 3 people over the age of 60 are affected by the disease. OA of th e h ip is ch aracterized by focal degen eration of articular cartilage, typically located in the weight-bearing region of th e fem oral h ead an d/ or acetabulum . As th e articular cartilage loss becom es m ore severe, the resulting altered joint reaction forces across th ese regions result in progressive cartilage loss. Th is self-perpetuatin g cycle results in bony rem odeling and continued cartilage destruction. Patients suffering from hip OA typically present with an in sidious on set of pain th at accompan ies activity an d is relieved by rest in addition to gradual loss of RO M. O ften , patien ts will com plain of difficulty with am bulation , a decreased ability to am bulate long distances, and an in creased struggle with rising from a seated position. Most symptom s will resolve with th e first few steps of walkin g but will recur after sitting for any extended period of tim e. As the hip join t approach es en d-stage degen eration , th e patien t m ay presen t with a limp or an talgic gait due to pain in h ibition of th e abductor complex. Patien ts with symptom s suspicious of OArequire at m inim um an AP pelvis and an AP and lateral hip radiograph. Additional radiograph ic im aging m odalities are not usually necessary to m ake th e diagnosis of OA. The typical radiograph ic features of th e diseased h ip can assist in differentiating OA from inflam m atory arthritis (Table 16.6). When determ in in g th e appropriate treatm ent regim en for a patient with h ip OA, it is important to take into accoun t patient’s age, presence of significant com orbidities, symptom severity, lim itation of function, exten t of arth ritic ch ange, and expected activity level. As with m ost diagnoses in orth opedics, the initial treatm ent strategy should be focused on n onoperative m an agem ent. Nonph arm acologic th erapy is th e m ain stay for th e treatm en t of hip OA. There has been a clear association between obesity an d th e developm en t an d progression of h ip OA. From th e first office visit, patien ts sh ould be coun seled on th e im portan ce of diet an d weigh t loss. Youn g, active patien ts sh ould be en couraged to stay active th rough lowimpact activities such as the elliptical m ach ine or swim m ing. Patien ts who present with lim ited hip ROM m ay ben-

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TABLE 16.6

RADIOGRAPHIC CRITERIA FOR DIFFERENTIATING OSTEOARTHRITIS FROM INFLAMMATORY ARTHRITIS ABOUT THE HIP JOINT Osteoarthritis

Inflammatory Arthritis

Eccentric joint space narrowing Bony

Symmetric joint space narrowing Periarticular osteopenia/ osteoporosis Joint erosion Ankylosis

Subchondral cyst Osteophyte formation

efit from aquatic th erapy to regain m otion an d m in im ize pain . Ph arm acologic th erapy can also be a powerful adjun ct to the nonoperative m anagem ent of h ip OA. Nonsteroidal anti-inflam m atory drugs (NSAIDs) are often prescribed on a daily basis to provide pain relief. Patien ts sh ould be advised that NSAIDs can affect ren al and hepatic function and, as a result, lon g-term use m ay be detrim ental. Cyclooxygenase-2 inhibitors are an alternative th at offer a lower side-effect profile. Addition ally, NSAIDs should be discon tin ued 5 to 7 days prior to any surgical in terven tion due to an in h ibitory effect on platelet fun ction an d prolonged bleeding tim es. For patien ts sufferin g from m ild osteoarth ritic symptom s, over the counter supplem ents such as Glucosam ine Chondroitin Sulfate, a glycosam inoglycan derivative, have been sh own to provide som e ben efit. In tra-articular adm in istration of viscosupplem entation agents is also an option, alth ough it is m uch m ore readily accepted in the treatm ent of m ild kn ee OA. Th is en tails a series of th ree or five in jections spaced 1 week apart. Typically, patien ts gain m oderate relief lasting from 6 m onths to 1 year; however, the use of in tra-articular viscosupplem en tation h as n ot been FDA approved for hip arthritis. Th e use of in tra-articular glucocorticoid in jection s h ave also not been studied extensively for the treatm ent of hip OA. However, th ey can be used diagn ostically in com bin ation with an anesth etic agen t in determ in in g whether h ip pain is referred (e.g., lum bosacral referred pain) or related to internal deran gem en t of the hip join t itself. Often youn ger patien ts with suspected labral path ology will un dergo in tra-articular adm in istration of corticosteroids alon g with a sh ort-acting analgesic (e.g., Lidocaine) at the tim e of an MR arthrogram . Pain relief derived from th e injection is diagn ostic for h ip path ology as th e cause for h ip sym ptom s. Given th e substantial soft-tissue envelope surroun din g th e h ip join t, in tra-articular in jection s are gen erally perform ed un der radiograph ic guidan ce to en sure accurate placem en t.

688


laborers and patients with a rem ote history of a septic arth ritis are still considered good surgical candidates for hip arth rodesis with consideration given to conversion to THA in the future. The optim al hip fusion position is hip flexion of 20 to 25 degrees, adduction of 5 degrees, and neutral rotation .

Figure 16.39 Arthroscopic photograph showing a labral tear

with adjacent acetabular chondral lesion. The femoral head is shown at the bottom of the photograph. (Reprinted with permission from Barrack RL. Master Techniques in Orthopaedic Surgery: The Hip. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)

Nonarthroplasty Alternatives for the Treatment of Hip Arthritis Hip Arthroscopy Th e use of h ip arth roscopy h as becom e in creasin gly popular in th e treatm en t of th e youn g adult arth ritic h ip. With th e diagn osis of fem oral–acetabular impingem ent as a leadin g cause for idiopathic hip OA, patients often presen t with m echanical hip sym ptom s due to labral tears (Fig. 16.39). Th is patien t population typically will un dergo h ip arth roscopy for visualization of th e join t an d debridem en t versus possible repair of labral tears. Arth roscopic exam in ation can aid in iden tifyin g th e precise location an d exten t of ch on dral degen eration an d addition al path ology th at m ay not have been clearly observed with plain radiograph ic or advan ced im agin g. Arth roscopic debridem en t of th e h ip facilitates th e rem oval of in flam m atory m ediators, degen erative cartilage, an d loose bodies. Debridem en t, ch on droplasty, an d rem oval of loose bodies is occasion ally useful in the m anagem ent of early-to-m oderate arthritis, with associated m ech an ical symptom s, wh ich m ay n ot be suitable for m ore exten sive procedures such as total h ip arth roplasty. Hip Arthrodesis Th e adven t of tech n ological advan ces in total h ip arth roplasty (THA) over th e past h alf cen tury h as m ade h ip arth rodesis essen tially obsolete for th e treatm en t of OA of th e h ip. However, because of th e con cern s over th e lon gevity of THA in youn ger patien ts, h ip arth rodesis rem ain s a possible treatm en t option . Th e m ain disadvan tages of th is procedure in clude progressive degen eration of th e ipsilateral kn ee an d lum bar spin e an d lim itation of activities of daily livin g such as puttin g on socks. Youn g

Osteotomies Osteotom ies or bony procedures around the hip joint m ay be classified on th e basis of location , pelvis, or proxim al fem ur, or by purpose, reconstructive, or salvage. Reconstructive osteotom ies are geared toward the treatm ent of a preexistin g h ip deform ity such th at th e procedure will preven t degen erative ch an ges from occurrin g prem aturely. Salvage option s rely upon operative correction of a preexisting degenerative hip pathology to reduce the patient’s sym ptom s an d delay th e need for possible arthroplasty. Th e gen eral goal of a h ip osteotomy is to redirect forces across the h ip joint from a degenerative area to a healthier region , preven tin g disease progression an d preservin g th e rem ain in g viable articular cartilage. A detailed discussion of th e differen t h ip osteotom ies is beyon d th e scope of th is textbook.

Total Hip Arthroplasty Total hip replacem ent is one of the m ost successful surgical procedures perform ed today with nearly 95% good-toexcellen t results at 15 years. Youn ger, m ore active patien ts are being considered surgical candidates for this procedure an d n early 250,000 THA procedures are perform ed annually in the United States. The overall goals of THA are to relieve pain an d improve fun ction th rough th e restoration of join t m obility, join t stability, an d an atom ic align m en t of the lower extrem ity.

Surgical Approaches to the Hip Th ere are several surgical approach es th at m ay be employed to gain access to th e h ip join t, each with distin ct advan tages an d disadvantages. The m ost com m on approaches in clude the anterior, anterolateral, the direct lateral, and the posterior approach . Th e an terior or Sm ith –Peterson’s approach uses the intern ervous plan e between th e Sartorius (in n ervated by th e Fem oral nerve) and the Tensor Fascia Lata (innervated by the Superior Gluteal n erve) (Fig. 16.40). The deeper dissection is carried out between the Rectus Fem oris (innervated by the fem oral nerve) and the Gluteus Medius (innervated by the Superior Gluteal nerve). Th is approach is typically used for irrigation an d debridem en t of th e pediatric septic h ip. However, with th e adven t of m in im ally in vasive techn iques for THA, th e two-in cision approach uses th e anterior approach for implantation of th e acetabular cup. Th e an terolateral or Watson –Jones’approach utilizes the interm uscular plane between the Tensor Fascia Lata (in n ervated by th e Superior Gluteal n erve) an d th e Gluteus


Tensor fasciae latae

689

Ilium

Gluteus medius Gluteus minimus

Anterior joint capsule

Rectus femoris

Figure 16.40 Smith–Peterson anterior

approach to the hip. (Adapted from Hoppenfeld S, deBoer P. Surgical Exposures in Orthopaedics: The Anatomic Approach. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2003.)

Medius (in nervated by the Superior Gluteal nerve). This is a true m uscle sparing approach but is n ot considered an intern ervous approach sin ce both m uscles are innervated by the sam e nerve. This approach gives excellent visualization for acetabular preparation, but access to the fem ur is sligh tly m ore challenging th an with the posterior approach. Th e direct lateral or Modified Hardin ge’s approach is a Gluteus Medius splittin g approach . Th e an terior on e-th ird of th e Gluteus Medius is divided to gain access to th e h ip capsule an d joint. This approach also provides excellen t visualization of the acetabulum but m ay result in an abductor lurch (Tren delen burg gait) in th e postoperative period, wh ile th e abductor com plex is h ealin g. Access to th e fem ur for fem oral component preparation requires adduction and external rotation of the lower extrem ity. Th e posterior or Moore’s approach is th e m ost com m on approach used for THA. Th is approach centers the incision over the greater trochanter. The in cision extends distally alon g th e fem oral sh aft, wh ile it is curved proxim ally over th e Gluteus Maxim us. Th is is a true m uscle splittin g (Gluteus Maxim us) approach an d requires resection of the sh ort external rotator (Piriform is, Superior and Inferior Gem ellus, an d O bturator In tern us) m uscles from th eir greater trochanteric in sertion site (Fig. 16.41). Access to the hip joint is ach ieved by in cising th e posterior hip capsule. This approach also gives excellent visualization of th e

acetabulum an d requires flexion , adduction , an d in tern al rotation of th e lower extrem ity for fem oral compon en t preparation . Upon closure of th is approach , th e posterior capsule and short extern al rotator m uscles are reattached to th e greater troch an ter. Th e biggest disadvan tage to th is approach is th e postoperative dislocation risk th at h as been reported to be as h igh as 2% to 7%. However, an adequate capsular repair has been sh own to m inim ize the incidence of postoperative dislocation .

Hip Implant Design and Methods of Fixation Total hip implants h ave evolved a great deal from th e early 1970s, th e tim e of th e first m odern THA perform ed in th e Un ited States. Initially, cem ented fixation of both th e acetabular an d fem oral com pon en t was advocated on th e basis of th e th eory th at cem en t in terdigitated with can cellous bone resulted in superior im m ediate implant fixation . However, in th e early 1980s, it was recognized that poor THA outcom es were associated m icrofracture an d fatigue failure of th e cem en t m an tle. Cem en ted cups were foun d to fail at a higher rate than cem ented stem s because cem ent is less able to resist th e shear an d tension forces seen by the acetabulum compared with compression forces seen by the fem ur. The focus shifted toward usin g cem en tless fixation for the acetabulum , while cem ent tech nique was im proved for th e fem ur. Improvem en ts in cem en t tech n ique

690

Orthopaedic Surgery: Principles of Diagnosis and Treatment Vastus lateralis Glureus medius

Greater trochanter

Short rotators

Figure 16.41 Posterior approach to the hip. (Adapted

from Hoppenfeld S, deBoer P. Surgical Exposures in Orthopaedics: The Anatomic Approach. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2003.)

in cluded th e adven t of vacuum m ixin g to decrease porosity, pressurization of th e cem en t upon in troduction in to th e fem oral canal, and th e use of a centralizer to en sure a uniform cem ent m antle. These improvem ents are referred to as third-generation cem ent techn ique and are currently used today. Despite th ese tech n ological an d m eth odological advances in cem ent techn ique, cem entless implantation of both compon en ts h as gain ed popularity with widen in g surgical indications and youn ger, m ore active patien ts requirin g THA. Today, m ost THA compon en ts are im plan ted usin g cem en tless fixation . Th e bon e on -growth or in growth an d rem odelin g poten tial associated with un cem en ted compon en ts is dyn am ic an d life lastin g. In th e settin g of revision THA, cem en tless fixation is preferred if th ere is adequate rem ain in g bon e stock. There are two differen t techniques for cem entless im plan t fixation : press fit an d lin e-to-lin e. In press fit, the im plan t is sligh tly larger th an th e ream ed size, creatin g com pression h oop stresses for tem porary fixation . In line-to-line fit, th e sam e diam eter im plan t as th e ream er is used an d exten sive porous coatin g provides th e in itial in terferen ce fit between th e prosth esis an d th e h ost bon e. Screws provide in itial fixation of th e acetabular cup in th e lin e-to-lin e fit but m ay also be required for adequate com pon en t stability when usin g th e press fit tech nique. Safe acetabular screw placem en t is en sured by usin g quadran ts on th e basis of the ASIS and cen ter of the acetabulum : posterior–superior is th e safe zon e; posterior–inferior is safe for screws less than 20 m m (sciatic nerve); an terior–in ferior m ay in jure

th e obturator n erve, artery, or vein ; an d an terior–superior is the “zone of death ’’(external iliac vessels) (Fig. 16.42). Cem en tless acetabular sh ells typically h ave a coatin g of plasm a spray, sin tered beads, or m esh m etal (e.g., fiber m etal) that allows for bony on-growth and eventual biologic fixation of the implant. Newer porous m etals such as porous tan talum are also bein g used as th e acetabular sh ell backin g th at aids in obtain in g better biologic fixation by bony in -growth . In itially, acetabular lin ers were implan ted usin g cem en t, an d cem en t m ay be used in salvage situation s with a well-fixed acetabular sh ell. Th e curren t gold stan dard is to use an uncem en ted acetabular shell with placem ent of a m odular acetabular lin er with in th e sh ell. Uncem ented fem oral components are classified as m etaphyseal fittin g or diaphyseal fittin g stem s. Metaphyseal stem s are anch ored in the trabecular bone of the in tertroch an teric region of th e proxim al fem ur. Proxim al loading of the fem ur decreases stress-shielding of the proxim al fem ur. Diaphyseal stem s bypass the trabecular bone of th e proxim al fem ur an d rely upon cortical bon e fixation within the fem oral canal, typically requiring 4 to 5 cm of scratch fit (Fig. 16.43). Diaphyseal fixation results in greater proxim al fem oral stress-shielding an d also m ay be associated with a higher in cidence of an terior th igh pain . Older patien ts with osteoporotic bon e m ay require distal fittin g stem s due to th e in ability to obtain adequate can cellous bon e fixation in th e proxim al portion of th e fem ur; however, these patients are at h igh er risk of thigh pain an d stress-sh ieldin g. Both stem types are com m on ly used in th e Un ited States, an d selection is based upon


691

Abdominal aorta Line A

Aortic bifurcation

Asis

Common iliac

Posterior superior Anterior superior

External italic vein Posterior inferior Obturator vein

Line B

Anterior inferior

Figure 16.42 Acetabular quadrant system for screw placement (Reprinted with permission from Wasieleski RC, et al. Acetabular anatomy and the transacetabular fixation of screws in THA. J Bone Joint Surg. 1990;72A:501–508.)

Figure 16.43 Radiographs of a ce-

mentless metaphyseal (A) and diaphyseal (B) fitting stems.

A

B

692


Figure 16.44 Cemented femoral stem with a 2-cm uniform

cement mantle.

surgeon’s preference as well as patien t anatom y an d bone quality. In several institutions in the United States an d worldwide, cem ented fem oral fixation is still con sidered th e gold stan dard. Cem en ted fem oral fixation h as a lon g track record, an d fixation is ach ieved via cem en t in terdigitation with the in terstices of can cellous bone. Th is technique can be utilized in patien ts with capacious can als wh ere bony fixation is n ot possible with a cem en tless device; h owever, it is n ot ideal for youn g patien ts or fem oral can als with th ick cortices. When cem ent is used, it is important to obtain a un iform cem en t m an tle an d avoid m an tle defects. Am an tle defect is a region in a cem en t colum n wh ere th e prosth esis touch es the bone an d serves as an area of con centrated stress associated with a higher loosen in g rate. If the fem oral stem is placed in a varus position (the distal aspect of the stem abuts the lateral fem oral cortex), upon im plan tation , there is a higher likelih ood of a stress riser an d even tual fixation failure. A cem en t m an tle of 2 m m aroun d th e en tire prosth esis is gen erally recom m en ded (Fig. 16.44).

Total hip Arthroplasty—General Principles and Hip Stability Ach ieving a stable total hip arth roplasty is a function of compon en t position in g, com pon en t sizin g/ fit, abductor complex/ soft-tissue ten sion , an d compon en t fixation . Proper align m en t of th e acetabular an d fem oral components is typically 20 to 30 degrees of acetabular anteversion , 35 to 40 degrees of acetabular inclination (th eta an-

gle), and 10 to 15 degrees of fem oral stem anteversion. Im proper align m en t can lead to an terior in stability (in creased acetabular anteversion), posterior instability (retroverted cup or stem ), troch an teric impin gem en t (decreased th eta), or superior instability (increased theta angle) (Table 16.7). Th e en d poin t of in stability is dislocation an d stability of th e con struct is typically con firm ed on th e operatin g room table prior to com pletion of th e procedure. On e of the m ajor contributors to hip stability and hip ROM is the ratio between the diam eters of the implant h ead an d implant neck, kn own as th e h ead-to-n eck ratio. Th e prim ary arc of m otion of th e h ip depen ds on th is ratio. The greater the head-to-neck ratio, th e greater the ROM th e fem oral com pon en t can un dergo prior to n eck im pin gem ent on the acetabular shell. Another determ inan t of hip stability is the excursion distan ce. Excursion distan ce is defin ed as th e distan ce th e h ead m ust travel to lever out of th e acetabular lin er once the n eck impinges on th e acetabular sh ell an d is typically half th e diam eter of th e h ead. Alarger diam eter h ead h as a larger excursion distan ce an d th us con fers greater h ip stability. In gen eral, th e largest h ead th at can be im plan ted safely is recom m en ded. Th e soft tissues surroun din g th e h ip are also of critical importan ce in attaining hip stability following THA. The h ip abductor complex (gluteus m edius an d m in im us) tension m ust be m ain tain ed for optim al h ip stability. When th ere is sign ifican t abductor complex laxity (i.e., wh en th e implanted components leave the lim b short), the lack of ten sion results in in stability of th e implan ted devices. Th e abductor tension is also affected by the degree of lateral offset of th e compon en ts utilized (th e m ore th e lateral offset, the greater the abductor ten sion). Optim al soft-tissue balan cin g is determ in ed in traoperatively with implan t stability determ in in g th e degree of ten sion required. Any process th at in terferes with proper soft-tissue fun ction (th e distan ce between th e cen ter of th e fem oral h ead an d th e tip of th e greater troch an ter) or coordin ation , such as stroke, dem en tia, delirium , or cerebellar dysfun ction , can in crease th e risk of postoperative h ip in stability. On e of the m ajor problem s facin g THA today is osteolysis secon dary to the gen eration of m icroscopic wear particles gen erated at th e articulatin g surface. Tradition al articular bearin g surfaces were h ard on soft (i.e., cobalt-ch rom e m etal on polyethylene plastic). The high wear rates and particle generation associated with hard on soft bearings has led to the developm ent of alternative bearing articulation s th at are h ard on h ard (m etal on m etal or ceram ic on ceram ic). Th ese h ard-on -h ard bearin gs h ave greatly im proved wear properties an d h ave been developed to improve im plan t lon gevity for th e in creasin g n um ber of youn g, active patien ts requirin g THA.

Complications Complications associated with total hip arthroplasty can be classified as in traoperative, early, and late postoperative.


693

TABLE 16.7

TOTAL HIP INSTABILITY WITH REGARD TO ACETABULAR CUP POSITION Instability Cup Position Cup Angle (◦ ) Pattern Anterverted

> 25◦

Position of Compromise

Anterior

■

ABDUCTION

VERSION

■

Retroverted

< 15◦

Posterior

■ ■

Vertical

> 50◦

Superior/ Lateral

■

Horizontal

< 40◦

Inferior

■

Major intraoperative complications include fractures or nerve an d vessel injury. In traoperative fractures are m ore com m on on the fem oral side than on th e acetabular side. Implan tation of an un cem en ted fem oral compon en t is m ore likely to result in a fem oral fracture due to the trem endous forces gen erated to obtain rigid fixation of th e device with in th e con fin es of th e proxim al fem ur. O n th e acetabular side, fractures typically occur wh en th ere is a large size discrepancy between th e ream ed acetabulum an d th e size of compon ent ch osen for implantation . Most fractures about the acetabulum are cortical defects, involve the posterior wall, an d do n ot require form al open reduction an d intern al fixation. While uncom m on , in jury to th e sciatic, fem oral, obturator, an d superior gluteal, or lateral fem oral cutan eous nerves can occur. Th e m ost com m on cause for n erve in jury associated with THA is erran t retractor placem en t. Th e m ost com m only injured nerve is the peroneal division of the sciatic n erve as it runs just posterior to the posterior wall of th e acetabulum . Addition ally, len gth en in g of th e lim b durin g THA by m ore th an 3.5 to 4 cm h as been associated with an in creased risk for sciatic n erve n europraxia or n erve stretch injury. Typically, n erve in juries that are n europraxic in nature will recover spontaneously, but full recovery m ay take m ore th an 6 m on th s. Vascular injury at the tim e of THA is typically associated with erran t acetabular screw placem en t. As m en tion ed earlier, the acetabulum is divided into four quadrants on the basis of a lin e exten din g distally from th e ASIS th at bisects the acetabulum (Fig. 16.42). A second line is drawn to divide the acetabulum into four equal quarters. The safe zon e is the posterior–superior quadran t, wh ile screw placem ent in the anterior–superior quadrant is contraindicated due to the proxim ity of the iliac vessels. In the even t of intraoperative in jury to the iliac vessels, the THA procedure should be

■

Extension External Rotation Flexion Internal Rotation

Reduction Maneuver Longitudinal traction ■ Hip extension ■ Abduction ■ Hip IR/ ER ■ Anterior traction ■ Hip flexion > 90◦ ■ Adduction ■ Hip IR/ ER

Adductin

Longitudinal traction ■ Adduction ■ Hip IR/ ER Abduction Longitudiral traction Greater trochanter ■ Abduction ■ Hip IR/ ER impingement

aborted, an d th e patien t sh ould be flipped in to th e supin e position with im m ediate access of th e abdom en by a gen eral or vascular surgeon to obtain con trol of th e bleedin g source. Early complication s followin g THA in clude in fection (deep join t), th rom boem bolic disease, an d dislocation (Table 16.7). In fection following a prim ary joint replacem en t, alth ough rare, is a poten tially devastatin g com plication . Th e in ciden ce of prim ary deep join t in fection is less th an 1% at m ost large cen ters th at perform a h igh volum e of join t replacem en ts an n ually. An importan t factor for preven tin g in fection is th e adm in istration of in traven ous an tibiotics with in 1 h our of m akin g th e surgical incision . The use of personal isolation suits and lam in ar flow h ave dem onstrated on ly m in or improvem ents in in fection rates. However, th e employm en t of all of th ese m odalities m ay h ave a syn ergistic effect in m in im izin g in fection following prim ary THA in the perioperative period (Fig. 16.45). Any patien t with n ew on set h ip pain followin g prim ary THAm ust be considered to h ave an in fected prosth esis until proven oth erwise. Th e algorith m for diagn osin g an in fected prosth esis begin s with plain radiograph s, an d laboratory work including a white blood cell coun t with differential, eryth rocyte sedim en tation rate an d c-reactive protein . Nuclear im agin g scan s can be h elpful in differen tiatin g between aseptic an d septic com pon en t loosen in g. Recen tly, the use of positron em ission tom ography scanning h as gain ed popularity in th e diagn osis of in fection followin g total join t replacem en t. Acute in fection s, defin ed as an in fection occurrin g with in 2 weeks of symptom on set, m ay be effectively treated with irrigation , debridem en t, an d lin er exch an ge. Subacute an d ch ron ic in fection s diagn osed greater than 4 weeks after the onset of symptom s or im plan tation of th e prosth esis are typically treated by a m ore

694


TABLE 16.8

THE VANCOUVER’S CLASSIFICATION OF POSTOPERATIVE PERIPROSTHETIC FEMORAL FRACTURES Type

Fracture Location

Subtype

A

Trochanteric region

B

Around or just distal to the stem

C

Well distal to the stem tip

AG (greater trochanter) AL (lesser trochanter) B1 (stable prosthesis) B2 (unstable prosthesis) B3 (inadequate bone stock)

Reprinted with permission from Callaghan JJ, Rosenberg AG, Rubash HE. The Adult Hip. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2007.

Figure 16.45 There is a synergistic effect seen with multiple

modalities used to minimize the risk for infection in primary total hip arthroplasty. (Reprinted with permission from Callaghan JJ, Rosenberg AG, Rubash HE. The Adult Hip. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2007.)

exten sive protocol detailed below in th e late com plications section. Th rom boem bolic disease refers to th e form ation of postoperative DVT, wh ich m ay result in pulm on ary em boli (PE). Th rom boem bolic disease is the m ost com m on com plication followin g prim ary THA; h owever, m ost are subclinical an d do not affect the clinical success of the procedure. Several regim en s m ay be employed for preven tion of DVT an d PE an d m ost utilize an an ticoagulan t agen t, such

A

B Figure 16.46 Periprosthetic fracture around a hip arthroplasty (A) preoperative x-ray, demonstrating a spiral fracture around a hemiarthroplasty and (B) postoperative radiograph. The fracture was treated with removal of the implant, cerclage of the fracture with two cables, and reimplantation of a total hip arthroplasty.


as warfarin, low m olecular weight h eparin, or aspirin for up to 6 weeks followin g surgery. Th e m ajor late complication s followin g prim ary THAin clude delayed or ch ron ic deep join t infection and periprosthetic fractures. When a subacute or chronic infection is diagn osed followin g THA, it is assum ed th at bacteria h ave form ed a glycocalyx around the implant, and thus, simple irrigation and debridem en t would be in adequate to eradicate the in fection. The typical treatm ent protocol for late infections requires rem oval of the implant, placem ent of an an tibiotic cem ent spacer, a directed course of intravenous an tibiotic therapy, an d reimplan tation of new THAcomponents when laboratory an d im aging studies dem on strate no signs of residual in fection. Approxim ately 90% of patients will be able to clear the infection with the use of this two-stage reimplantation technique. Periprosth etic fractures are fractures that occur around a well-fixed THAcon struct. Fractures about th e fem oral com pon en t are m ore com m on th an fractures about th e acetabulum ; h owever, acetabular fractures m ay be seen in cases with sign ifican t acetabular bon e loss an d loss of m edial wall in tegrity. Periprosthetic fractures of th e fem ur are classified on the basis of (a) th e level of th e fracture about the fem ur an d (b) the quality of fixation of the fem oral stem . The Vancouver’s classification is th e m ost com m on periprosth etic fracture classification used to describe th ese fractures (Table 16.8). Treatm en t is dictated on th e basis of th e stability of the prosthetic componen t, with loose or un stable components requirin g revision THA. Fractures at the level of th e intertrochan teric region often do n ot require surgical fixation. Fractures distal to the stem tip can be treated with a plate th at overlaps th e distal portion of th e fem oral stem . Fractures th at exten d th rough th e region of th e stem are treated with plates and cables or revision surgery on the basis of th e stability of th e fem oral compon en t. In gen eral, a revision stem m ust exten d two cortical diam eters of the fem ur beyon d the level of the fracture to get adequate fixation (Fig. 16.46).

Osteonecrosis Osteonecrosis, also referred to as AVN, is defined as death of periarticular bon e from an etiology oth er th an in fection , with th e fem oral h ead bein g th e m ost com m on ly affected area in th e body. The in cidence is approxim ately 20,000 new cases in the Untied States an nually, and osteonecrosis comprises the original diagnosis for nearly 10% of all total h ip arth roplasties perform ed each year. Osteon ecrosis typically results from a disruption of the blood supply either secondary to traum a or other causes such as system ic steroid use, alcohol abuse, blood dyscrasias such as sickle cell disease, coagulopathies (protein C or S deficiency or low lipoprotein level), caisson disease, excessive radiation therapy, an d m etabolic storage diseases such Gaucher’s disease. Cases of idiopath ic fem oral h ead osteon ecrosis is

695

com m only seen in the pediatric population an d is term ed Legg–Calve–Perthes’ disease. Osteonecrosis typically involves the anterolateral portion of th e fem oral h ead an d m ay result in h ead flatten in g an d even tual h ead collapse. Th e path ogen esis of th e disease leads to n ecrotic subch on dral bon e an d subch on dral collapse. Th e h istopath ologic ch an ges are ch aracterized as follows: (a) in flam m ation with in vasion of prim itive m esen chym al tissue an d capillaries; (b) deposition of n ew lam ellar bone on n ecrotic trabecular bon e; an d (c) rem odelin g of n ecrotic trabecular bon e by a process kn own as creepin g substitution. Bon e is weakest during the rem odelin g ph ase, leadin g to poten tial subch on dral collapse (crescent sign) and fragm entation . On physical exam ination, patients typically present with decreased h ip abduction an d in tern al rotation an d a sligh t limp durin g am bulation . Comparison to th e con tralateral h ip is an importan t adjun ct to th e physical exam ination , alth ough up to 80% of patien ts with steroid-in duced AVN will have bilateral h ip in volvem ent. Radiograph ic evaluation of AVN sh ould start with plain radiographs of the pelvis and two views of the involved

TABLE 16.9

UNIVERSITY OF PENNSYLVANIA SYSTEM FOR STAGING AVASCULAR NECROSIS Stage Criteria 0 I

II

III

IV

. V

VI

Normal or nondiagnostic radiography, bone scan, MRI Normal radiographs, abnormal bone scan, and/or MRI A. Mild (< 15% of femoral head affected) B. Moderate (15%–30%) C. Severe (> 30%) “Cystic” and sclerotic changes in femoral head A. Mild (< 15% of femoral head affected) B. Moderate (15%–30%) C. Severe (> 30%) Subchondral collapse (crescent sign) without flattening A. Mild (< 15% of articular surface) B. Moderate (15%–30%) C. Severe (> 30%) Flattening of femoral head A. Mild (< 15% of surface and < 2-mm depression) B. Moderate (15%–30% of surface or 2- to 4-mm depression) C. Severe (> 30% of surface or > 4-mm depression) Joint narrowing or acetabular changes A. Mild Average of femoral head involvement, as determined in stage IV, and estimated acetabular involvement B. Moderates C. Severe Advanced degenerative changes

Reproduced from Steinberg ME. Diagnostic imaging and the role of stage and lesion size in determining outcome in osteonecrosis of the femoral head. Tech Orthop. 2001;16:6–15. Reprinted with permission from Steinberg ME, et al. Tech Orthopaedics. 2001;16:6–15.

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hip. MRI can be utilized to detect early cases with very h igh sen sitivity and specificity. Nuclear m edicin e bone scan s can also be used for early diagn osis, dem on stratin g in creased uptake in areas of bon e rem odelin g. Several classification s system s h ave been h istorically used to defin e th e severity of in volvem en t of th e fem oral head as well as patient progn osis. The University of Penn sylvania System for Staging Avascular Necrosis evaluates both th e radiograph ic appearan ce of th e lesion as well as the size of the lesion (Table 16.9). Th is classification determ in es th e likelih ood of success wh en usin g join t-preservin g procedures such as core decom pression . Treatm en t for osteon ecrosis of th e h ip ran ge from con servative symptom atic therapy with a focus on m ain tainin g h ip ROM to join t-preservin g altern atives for early AVN to h em iarth roplasty or THA for en d-stage AVN. Join tpreservin g altern atives in clude core decom pression , vascularized fibular graftin g, an d proxim al fem oral osteotomy. Core decompression in volves drillin g a 6 to 10 m m wh ole up th e fem oral n eck in to th e area of n ecrotic bon e in

an attempt to stim ulate revascularization and h ealing. Som e surgeons will augm ent th e procedure by packing th e area with bon e graft. Th e results of th is procedure declin e rapidly if th ere is any collapse of th e articular surface. In th e en d-stages of AVN with associated acetabular changes and hip joint degeneration, THA is th e treatm ent of ch oice; h owever, th ere is an in creased failure rate in th is younger patient population compared with THA for OA.

RECOMMENDED READINGS Lorich DG, Geller DS, Nielson JH. Osteoporotic pertroch an teric hip fractures: m anagem en t and current controversies. J Bone Joint Surg Am. 2004;86:398 –410. Lieberm an JR, Berry DJ, Mon tv MA, et al. Osteon ecrosis of the hip: m anagem ent in the twenty-first cen tury. J Bone Joint Surg Am. 2002;84:834 –853. Sierra RJ, Trousdale RT, Gan z R, Leun ig M. Hip disease in th e youn g, active patient: evaluation and nonarthroplasty surgical options J Am Acad Orthop Surg. 2008;16:689 –703. Barrack RL. Dislocation after total hip arthroplasty: im plant design and orientation. J Am Acad Ortho Surg. 2003;11:89 –99.

Knee and Leg Injuries Todd Rim in gton

John Klim k iewicz

17

Freddie Fu

INTRODUCTION Pain or injury about the knee and leg is one the m ost frequent condition s prompting a patient to seek evaluation by an orth opaedist. The purpose of this chapter is to review th e fun ction al an atomy an d evaluation of th e knee an d leg and to describe the presentation an d treatm en t of the m ost com m on traum atic and atraum atic injuries to th is area. Kn ee arth ritis an d arth roplasty, in cludin g periprosth etic fractures about th e kn ee, will be discussed in Ch apter 18.

FUNCTIONAL ANATOMY Th e kn ee is composed of th ree separate articulation s: th e tibiofem oral, patellofem oral, and the proxim al tibiofibular joints. The joint m ost com m only referred to when describing the “knee joint’’is th e tibiofem oral joint. Th e kn ee is also divided into th ree compartm ents: m edial, lateral, an d patellofem oral. Th e m edial an d lateral compartm ents comprise the tibiofem oral articulations (Fig. 17.1). Th e distal fem ur is composed of m edial an d lateral con dyles with the slightly larger and distal m edial condyle accountin g for the valgus orientation of the n orm al knee joint. Th e patellofem oral com partm en t lies in th e an terior kn ee an d con tains the patellofem oral articulation (Fig. 17.2). The sulcus between th e fem oral condyles is called the trochlear groove. The patella tracks within this groove as the kn ee is ranged through flexion and extension. At th e distal en d of th e fem ur between th e fem oral con dyles, th ere is an in tercon dylar n otch . Th e cruciate ligam en ts of th e kn ee are found within this intercondylar notch. O n the m edial aspect of th e distal fem ur is th e m edial epicon dyle, wh ich serves as th e insertion of the adductor m agn us and th e origin of th e m edial collateral ligam en t (MCL). Th e lateral epicon dyle on th e lateral aspect of th e distal fem ur serves as the origin of the lateral collateral ligam ent (LCL).

Th e tibiofem oral join t is a m odified h in ge join t. Th e greatest range of m otion occurs in the sagittal plane (flexion an d exten sion ). Th e kn ee can also m ove in th e coron al plan e (varus an d valgus) an d th e axial plan e (in tern al an d extern al rotation ). Th e ch on dral surfaces of th e fem oral condyles articulate with the chondral surfaces of the tibial plateaus. Both m edial an d lateral plateaus are relatively flat in sh ape wh en viewed in th e coron al plan e. However, in th e sagittal plan e, the con tours of the plateaus are differen t. Th e m edial plateau dem on strates a gen tle con cavity into wh ich th e m edial condyle fits. On sagittal m agnetic reson ance im agin g (MRI) scan s, th is is described as looking like a golf ball (m edial fem oral con dyle) on a tee (m edial tibial plateau) (Fig. 17.3). In con trast, th e lateral plateau dem on strates a con vexity and is sligh tly incongruous with th e lateral fem oral con dyle. Th erefore, th e bony arch itecture of the tibiofem oral joint alone is relatively incongruen t. Th e m en isci provide en h an ced stability to th e kn ee join t. Th ey are m edial and lateral fibrocartilagin ous structures that provide an in terface between the adjacent articular surfaces of th e tibiofem oral joint. Th e m edial m eniscus is sem icircular in shape, and the lateral m eniscus is m ore circular (Fig. 17.4). Th ey are firm ly con n ected to th e tibial plateaus through ligam ent fibers to the tibia called th e meniscotibial or coronary ligaments. Th e m enisci are also attached to the fem ur by th e m eniscofem oral ligam ents. Although they are firm ly attach ed, som e m ovem en t is perm itted. Th e lateral m en iscus is m ore m obile th an th e m edial m en iscus, accounting for the decreased prevalen ce of lateral m eniscus tears. Th e m ovem en t of th e m en isci allows th em to con form to the m oving joint surfaces and avoid position s of sh eer. Th e lateral m en iscus’s greater m obility is approxim ately 1 cm in th e an terior–posterior plan e compared with the m edial m en iscus’s 0.5 cm . This is the result of th e lack of attach m en t of th e lateral m en iscus alon g th e posterolateral aspect of th e kn ee at th e popliteal h iatus wh ere th e popliteal ten don passes in tra-articularly th rough th e popliteal h iatus.

698


Figure 17.1 The medial and lateral condyles. (Reproduced with

permission from Johnson DH and Pedowitz RA: Practical Orthopaedic Sports Medicine and Arthroscopy. Philadelphia: Lippincott Williams & Wilkins, 2006.)

The m enisci provide several im portant functions. First an d m ost important is the transm ission of join t stresses. As a result of th eir con form in g an atomy, th e m en isci distribute the forces across the joint surfaces to a larger area and decrease the peak contact stresses. The presence of a m en iscus helps to protect th e articular surfaces of the knee from excessive peak contact stresses. Biom echanical studies have

Figure 17.2 The patella articulation with the trochlea of the femur. (Reproduced with permission from Johnson DH and Pedowitz RA: Practical Orthopaedic Sports Medicine and Arthroscopy. Philadelphia: Lippincott Williams & Wilkins, 2006.)

Figure 17.3 A sagittal magnetic resonance imaging of the me-

dial compartment of the knee demonstration to conformity of the convex femoral condyle and the concave medial tibial plateau. A vertical tear of the posterior horn of the medial meniscus is also seen. (Reproduced with permission from Chapman MW, Szabo RM, Marder R, et al. Chapman’s Orthopaedic Surgery. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2001.)

sh own in creases in contact pressures up to 300% following m eniscus rem oval. The m edial m en iscus transm its 50% of th e join t force an d th e lateral m en iscus tran sm its up to 70% of th e join t force across th e kn ee. Addition al fun ction s of th e m en iscus in clude im proved join t stability, im pact absorption, an d articular n ourish m ent. Th e bon e of th e distal fem ur an d proxim al tibia is covered by a h igh ly organ ized structure of hyalin e cartilage. Th e articular cartilage th ickn ess varies with location . Th e patella h as th e th ickest articular cartilage in th e h um an body, an d it is 8 to 10 m m th ick. Th e cartilage is com posed of type II collagen , wh ose structure allows it to absorb im pact an d accom m odate to th e variable forces of com pression , tension , an d sh eer seen in this joint. Although joint congruen ce through the bone an d m en iscal anatomy provides som e inherent stability, m ost join t security is con ferred by th e surroun din g soft tissue structures, includin g th e joint capsule and ligam ents. Th e capsule of th e knee is a variably th ick structure lined by syn ovium . This layer is responsible for th e syn ovial fluid production th at accoun ts for th e kn ee’s low coefficien t of friction . Perh aps the m ost important m acrom olecule synthesized by the synovium is hyaluronic acid, which serves to lubricate th e join t surfaces. Extern al to th e syn ovium is the fibrous capsular en velope of the kn ee, which varies in

Chapter 17: Knee and Leg Injuries

699

Figure 17.4 Superior surface of tibia with superimposed medial and lateral menisci. (After Helfet AJ. The Management of Internal Derangements of the Knee. Philadelphia: JB Lippincott, 1963. Reproduced with permission from Chapman MW, Szabo RM, Marder R, et al.: Chapman’s Orthopaedic Surgery, 3rd ed. Philadelphia: Lippincott Williams & Wilkins, 2001.)

thickness accordin g to the region. Som ewhat thin in th e an terior portion of the kn ee, it is thicker and reinforced by n um erous discrete fibrous ligam en t complexes posteriorly. Th e posterolateral rein forcem en t is th e arcuate ligam ent and posterom edially is the posterom edial oblique ligam ent. Th e ligam en ts of th e kn ee are respon sible for m ost join t stability and include the collateral ligam en ts and th e cruciate ligam ents. These ligam ents are discrete collagen bun dles that connect one bone to another. The cruciate ligam ents provide stability in th e sagittal an d axial plan es. Th e cruciate ligam ents work together to guide the articular surfaces durin g kn ee m otion . Th ey are critical in m ain tain in g th is norm al relationship. The anterior cruciate ligam ent (ACL) origin ates from a broad footprin t on th e an terom edial tibia, passes th rough th e in tercon dylar n otch , an d attach es to th e posterolateral aspect of th e in tercon dylar n otch on th e lateral fem oral con dyle. Th e average len gth of th e ACL is 32 to 33 m m . Th e ACL is divided in to two separate bun dles, th e posterolateral an d an terom edial bun dles. Th ey are n am ed by their tibial insertion. The an terom edial bundle is reconstructed in a traditional ACL reconstruction. Th e tension in the two bundles varies with the position of the kn ee; the anterom edial bundle is tight in flexion, an d the posterolateral bundle is tigh t in extension (Fig. 17.5). The ACL is the prim ary restraint to anterior tibial translation. The m iddle geniculate artery is the blood supply of the cruciate ligam ents. Th e posterior cruciate ligam en t (PCL) crosses posterior to th e ACL with in th e in tercon dylar n otch . Th is cross form ation with th e notch is th e reason they are called cruciate ligaments. Th e PCLarises on th e posterior aspect of th e tibial plateau, passes th rough th e in tercon dylar n otch posterior to th e ACL, an d in serts on th e an terom edial aspect of th e notch of th e m edial fem oral condyle. The average len gth of th e PCL is 38 m m . Th e two bun dles of th e PCL are th e

an terolateral an d posterom edial bun dles. Th e ten sion in the two bundles varies with the position of th e knee; th e an terolateral is tigh t in flexion , an d th e posterom edial is tigh t in exten sion (Fig. 17.6). Th e PCL is th e prim ary restrain t to posterior tibial translation. Th e collateral ligam en ts provide stability in th e coron al plan e. Th e MCL is com posed of two discrete bun dles: a superficial bun dle an d a deep bundle (Fig. 17.7). The superficial MCL arises from th e m edial epicon dyle of th e fem ur an d travels in feriorly to a broad proxim al m edial tibial

Figure 17.5 The two bundles of the anterior cruciate ligament (ACL). (Reproduced with permission from Johnson DH, Pedowitz RA. Practical Orthopaedic Sports Medicine and Arthroscopy. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

700


Figure 17.6 The two bundles of the posterior cruciate liga-

ment (PCL). (Reproduced with permission from Johnson DH, Pedowitz RA. Practical Orthopaedic Sports Medicine and Arthroscopy. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

attach m en t approxim ately 8 cm in ferior to th e m edial join t lin e. Th e deep MCL is composed of th e capsule of th e m edial kn ee join t. Th e MCL is th e prim ary restrain t to valgus stress about th e kn ee. Th e LCL travels from th e lateral fem oral epicondyle to th e fibular head (Fig. 17.8). It can be palpated wh en th e kn ee is in th e “figure-of-four’’position . Th e LCL is th e prim ary restrain t to varus force about th e knee. The patellofem oral join t consists of th e in tercon dylar groove in th e an terior distal fem ur an d th e patella. Th e patella is a sesam oid bon e en cased with th e quadriceps m ech an ism . Th e patella in creases th e power of th e quadriceps m ech anism by m ovin g th e quadriceps m echan ism an terior to th e cen ter of th e kn ee join t. Th is in creases th e m om en t arm of th e quadriceps an d decreases th e force n ecessary to actively exten d th e kn ee. Clin ical data sh ow th at patien ts treated with rem oval of th e patella (patellectom y) experien ce 30% weakn ess in th eir quadriceps m ech an ism . The patella articulates with the distal fem ur in its troch lear groove. Th e posterior surface of th e patella contains m edial an d lateral facets that congruen tly track within th e troch lear groove in a very specific m anner. Th e patella is loosely h eld in place by its an atom ic con vex– concave arrangem ent an d by th e m edial an d lateral retinacular ligam ents. Th e patellofem oral joint carries large loads, particularly durin g activities in wh ich th e kn ee is flexed. During stair clim bing th e patellofem oral joint can

Figure 17.7 The structures of the medial side of the knee. (Re-

produced with permission from Johnson DH, Pedowitz RA. Practical Orthopaedic Sports Medicine and Arthroscopy. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

experien ce loads 3 tim es th e body weigh t, th is in crease to as m uch as 6 tim es the body weight with stair descen t. Th e fin al join t of th e kn ee is th e proxim al tibiofibular join t. Th is join t is often overlooked an d an occasion ally un recogn ized source of kn ee or leg pain . A diarth rodial join t, the articular surfaces are surroun ded by a synovial-lined capsule with strong reinforcing anterior and posterior ligam en ts. This joint is at risk of developin g the sam e path ology as that seen in other joints, including arthritis, traum a, and syn ovial disease. Th e m ost importan t m uscles aroun d th e kn ee in clude the quadriceps m echanism anteriorly, the ham strings posteriorly, th e pes ten don s m edially, an d th e iliotibial (IT) ban d laterally. Th e quadriceps m ech an ism is composed of four m uscles: th e rectus fem oris, vastus lateralis, vastus interm edius, and the vastus m edialis. The rectus fem oris arises from the anterior inferior iliac spin e and the hip capsule an d inserts on to the tibia. The rem aining quadriceps m uscles originate on the fem ur an d insert with the rectus fem oris as the patella tendon at th e tibial tubercle. All four m uscles are innervated by the fem oral n erve. The quadriceps m echanism is the prim ary extender of the knee. Posteriorly, the ham strings origin ate from the isch ial tuberosity and travel distally to attach on the posterior tibia


701

Figure 17.9 Transverse section through the distal femur. A: The

retinacular fibers, which are the conjoined layers I and II. B: The conjoined layer-II and -III fibers posterior to the medial collateral ligament. (Redrawn from Warren LF, Marshall JL. The Supporting Structures of the Medial Side of the Knee. J Bone Joint Surg 1979; 61-A:56. Reproduced with permission from Chapman MW, Szabo RM, Marder R, et al.: Chapman’s Orthopaedic Surgery, 3rd ed. Philadelphia: Lippincott Williams & Wilkins, 2001.)

Figure 17.8 The structures of the lateral side of the knee. (Re-

produced with permission from Johnson DH, Pedowitz RA. Practical Orthopaedic Sports Medicine and Arthroscopy. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

an d fibula. Medially, the sem im em branosus and sem iten din osus in sert at th e proxim al tibia an d posterom edial capsule. Laterally, the biceps fem oris in serts along the fibular head. Branches of the sciatic nerve inn ervate the ham strin g m uscles. The ham strings are th e prim ary flexors of the knee. Th e ten don s of th e gracilis, sem iten din osus, an d sartorius are foun d m edially (Fig. 17.9). Th ese ten don s arise from th e pubis, ischial tuberosity, and anterior superior iliac spin e (ASIS), respectively, and insert over the anterom edial aspect of th e proxim al tibia superficial to th e MCL. Th e appearance of these three structures led Greek observers to describe th em structure as a “pes anserine’’ in its sim ilarity to a duck’s webbed foot. Clin ically, th is structure is respon sible for symptom s wh en its un derlyin g bursa becom e irritated (pes bursitis) an d is a popular source of autograft ten don s durin g recon structive surgery. Laterally, the IT band is a strong broad flat ban d that origin ates at th e iliac crest, receives in sertion s of th e gluteus m axim us an d ten sor fascia lata, an d travels in feriorly to in sert at Gerdy’s tubercle on th e proxim al an terolateral

tibia (Fig. 17.10). From 0 to 30 degrees, the IT band con tributes to knee extension. Beyond 30 degrees, the IT band con tributes to kn ee flexion . Th e IT ban d is clin ically relevan t in causing a friction syndrom e over the lateral aspect of th e kn ee, kn own as runner’s or cyclist’s knee. The IT band is also th ought to be m echan ically responsible for the pivot sh ift m an euver seen in ACL deficiency. Posteriorly, there are several other m uscle groups of importance, including the m edial an d lateral gastrocnem ii, which originate from their respective posterior fem oral con dyles alon g with an in direct slip from th e join t capsule. Th e gastrocn em ii com bin e with th e soleus to from th e triceps surae m uscle, wh ose ten din ous portion is kn own as the Ach illes tendon. Deep to th e gastrocnem ii, origin ating from the m idpoint of the posterior proxim al tibia, is the popliteus m uscle. Th e popliteus travels superolaterally an d en ters th e kn ee join t capsule directly posterior to th e lateral m eniscus and exits again to attach just inferior to the lateral epicon dyle. Th e in sertion of th e popliteus is an terior an d distal to th e LCL origin. This structure is important in con tributin g to n orm al kn ee fun ction by un lockin g th e tibial plateau via internal rotation of the tibia at th e beginn ing of kn ee flexion . Th ere are a n um ber of bursae in th e kn ee, in cludin g the prepatellar, pes, IT, an d sem im em branosus bursae. All of th ese bursae are syn ovial-lin ed poten tial sacs th at serve as lubricated interfaces between adjacent m oving surfaces. Th e prepatellar bursa is detected on ly wh en it becom es sym ptom atic an d in flates in respon se to traum a or irritation, m ost com m only in patients with direct traum a to th e an terior aspect of th eir kn ee. Repetitive or direct traum a leads to inflam m ation, occasional th ickening, and

702


Quadriceps tendon

Vastus lateralis m.

Iliotibial band

Patella

Biceps femoris m.

Lateral patellar retinaculum Patellar ligament

Common peroneal n. Lateral head of gastrocnemius m. Peroneus longus m.

Illiotibial band (insertion site at Gerdy’s tubercle) Tibial tubercle

Soleus m. Tibialis anterior m. Extensor digitorum longus m.

swelling. The pes bursa lies between the pes tendon s an d the underlying anterom edial tibia. Inflam m ation here often leads to an terom edial kn ee pain . Laterally, in flam m ation an d irritation of th e IT ban d over th e lateral epicon dyle is a com m on problem in run n in g ath letes an d cyclists, leadin g to ITban d friction syn drom e. Fin ally, a bursa in th e posterom edial aspect of th e kn ee between th e posterom edial capsule and the sem im em bran osus can becom e swollen an d h istorically h as been called a Baker cyst. A Baker cyst is m ost com m on ly located between th e sem im em bran osus an d th e m edial h ead of th e gastrocn em ius. More recen tly, clinicians recognize that this structure is in fact a prom inent sem im em branosus bursa. Important neurovascular structures about the kn ee in clude the posterior fem oral artery, which becom es the popliteal artery at th e adductor h iatus. Distal to th e join t, the popliteal artery divides into three branches: an anterior branch, the anterior tibial artery, which travels anterior piercin g th e in terosseous m em bran e; a posterior bran ch , the posterior tibial artery; and a lateral branch, the peron eal artery. Th is trifurcation is of clin ical sign ifican ce because it tethers th e popliteal artery to th e posterior tibia, m akin g it vuln erable to in jury durin g leg traum a. Importan t n erves in clude th e sciatic n erve, wh ich run s with th e popliteal artery, an d bran ch es in to th e tibial n erve, wh ich run s with the posterior tibial artery, and the com m on peron eal n erve, wh ich travels laterally aroun d th e fibular n eck. Th ere are also several sm aller n erves of clin ical sign ifican ce. Th e in frapatellar bran ch of th e saph en ous n erve travels alon g th e m edial aspect of th e kn ee an d provides sen sation to th e an terom edial an d lateral sen sory derm atom es. Th is n erve’s proxim ity to th e com m on an terior, m idlin e

Figure 17.10 A slightly anterolateral view

of the outer layer of the knee. The lateral patellar retinaculum, the biceps femoris, and the iliotibial band constitute the outer layer. (Adapted from Hoppenfeld S and deBoer P: Surgical Exposures in Orthopaedics, 3rd ed. Philadelphia: Lippincott Williams & Wilkins, 2004.)

surgical approach to th e knee puts it at risk for dam age with th is approach . It is also at risk durin g h arvestin g of th e m edial h am strin g ten don s an d m edial exposures of th e kn ee for open m en iscal repair. Dam age can result in a neurom a m edially or a sen sory deficit along th e anterolateral aspect of th e leg. Th e obturator n erve provides in n ervation to th e distal m edial th igh an d is of little sign ifican ce in th e adult population , but in ch ildren , it m ay be a source of referred h ip pain. Th e com m on peron eal n erve provides m otor an d sen sory in nervation to the anterior and lateral compartm ents of the leg and foot and is vuln erable as it courses anteriorly aroun d the fibular neck. The nerve is vulnerable to both traum atic an d iatrogen ic in jury from surgical exploration on th e lateral side of th e kn ee. Th e superficial peron eal n erve is at risk durin g surgery on th e lateral com partm en t of th e leg. In th e leg, th ere are four m uscular compartm en ts, in cludin g th e an terior, lateral, superficial posterior, an d deep posterior (Fig. 17.11). Each h as specific m uscle groups an d n eurovascular structures surroun ded by a fascial envelope. Th e risk of in creased pressure with in th is en velope due to traum a, disease, or overuse m akes recogn ition an d understandin g of th e an atom y of each of these compartm ents clin ically im portan t. Th e an terior com partm en t is com posed of th e tibialis an terior, exten sor digitorum , an d th e exten sor h allicus lon gus. Th e deep peron eal n erve an d th e anterior tibial artery supply the anterior compartm ent. The lateral compartm ent is composed of th e peroneus longus and brevis. Th e superficial peron eal nerve con tributes m otor supply to this compartm en t, which is divided from the anterior compartm ent by the lateral in term uscular septum . Posteriorly, th ere are two separate compartm ents: the deep

Chapter 17: Knee and Leg Injuries Anterior Compartment

Lateral Compartment

703

facilitates a tailored exam ination in th e con text of the differen tial diagnosis. Th e exam in er sh ould always take advan tage of th e body’s sym m etry. Th e opposite kn ee an d leg serve as an excellen t con trol th at can h elp distin guish a n orm al from an abn orm al exam in ation with respect to atrophy, swellin g, m otion , stren gth , an d stability. Because of n orm al variability with in th e population , th e use of th e patien ts opposite lim b can m ake diagn ostic evaluation m ore accurate. Finally, it is important for the physician to rem em ber that kn ee symptom s can be caused by pathology elsewh ere. Com m on sources of referred pain in adults are the spin e an d hip, an d in children, kn ee pain is considered hip path ology un til proven oth erwise.

History

Deep Posterior Compartment

Superficial Posterior Compartment

Figure 17.11 The four compartments of the leg. (Reproduced

with permission from Bucholz RW, Heckman JD, Court-Brown C, Tornetta P. Rockwood and Green’s Fractures in Adults, 6th Ed. Philadelphia: Lippincott Williams & Wilkins, 2005.)

Obtainin g a careful h istory is as important as the actual physical exam in ation . Th e m ost com m on presen tin g sym ptom s include pain, swellin g, givin g way, clicking, catching, and locking. First, determ ine the patien t’s chief complaint. Th e m ost com m on complain t is th at of kn ee pain . Next, gath er inform ation about the chief complaint. The following 10 questions are important to any knee history. 1. Wh en was th e on set of th e pain ?

an d superficial compartm ents. The deep compartm ent is composed of the flexor digitorum , flexor hallucis longus, an d posterior tibialis. The superficial compartm ent is com posed of th e soleus, th e gastrocn em ii, an d th e plan taris ten don . All posterior compartm en t m uscles are supplied by the posterior tibial nerve.

Acute injuries are suggestive of ligam ent injuries, m en iscus in juries, or fractures. It is importan t to determ in e th e in citin g even t. Th e m ech an ism of a traum atic injury is important to determ ine the severity of the traum atic force applied to the join t. Ch ron ic in juries are m ore likely degen erative in n ature. 2. Wh ere (poin t to it) does th e pain h urt th e m ost?

EVALUATION OF THE KNEE AND LEG Th e evaluation of th e kn ee an d leg depen ds on an un derstan ding of norm al kn ee anatomy, techniques of physical exam in ation , an d fam iliarity with com m on kn ee con ditions. A history and physical exam ination, complem ented as necessary by radiograph s, can diagn ose m ost problem s. Special tests are n ot com m on ly required, alth ough MRI is som etim es helpful. Although fam iliarity with how to perform a system atic knee exam in ation approach is important, a comprehensive exam in ation is n ot usually required in every patien t. In stead, the exam ination should be tailored to the patient’s presen tation . For example, exam in ation of a 72-year-old with progressive kn ee pain sh ould be differen t from th e exam in ation of an 18-year-old football player followin g a traum atic injury. Un derstanding how to perform a basic overall exam ination is an im portant skill, but kn owing wh en to perform th e various specific exam in ation tech niques is a learned art. A thorough history usually alerts the exam iner to the m ost likely diagnostic con ditions and

Patien ts can gen erally localize th eir pain to a specific pain generator. Th e location of the pain can h elp lim it th e in jury to a specific com partm en t of the knee. Anterior knee pain is typical of patella disorders. Medial or lateral join t lin e pain is gen erally a ch on dral in jury or a m en iscus in jury. 3. Wh at is th e n ature of th e pain ? Patella disorders are typically a dull ache. Meniscus injuries are typically a sharp, catching pain. 4. Wh at m akes th e pain worse? Most kn ee in juries are worse with activity. Patella disorders are worse with ascen din g or descen ding stairs and sitting for prolonged periods in a chair. Meniscus injuries are worse with twisting, turn ing, or squatting m ovem ents. Cycling or rowing m ay exacerbate IT band syndrom e. 5. When did the knee first swell, an d does it continue to swell?

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Th e on set of swellin g after th e in jury is importan t. In traarticular swellin g or effusion with in the first 2 h ours after traum a suggests hem arth rosis. Hem arthrosis can be caused by ACL tear, peripheral m eniscus tear, or chondral injury such as with a kn ee dislocation , wh ereas swellin g that occurs overnight usually is an indication of acute traum atic syn ovitis. Th is can be a reaction to th e traum atic in jury an d is less specific. Th e frequen cy of swellin g sh ould be determ in ed. Causes of recurren t swellin g in clude syn ovial disorders such as in flam m atory arth ritis, degen erative arth ritis, gout, an d pseudogout. 6. Does th e kn ee “give way’’? Th is gen erally reflects a fun ction al weakn ess in which the quadriceps suddenly stops con tractin g, allowin g th e kn ee to in volun tarily ben d or “give way.’’Givin g way is a nonspecific symptom that can occur in patellofem oral pain syndrom e, patellar in stability, m en iscus tears, ligam en t in juries, an d ch on dral in juries. Th is process is often due to “reflex in h ibition of pain ,’’ in wh ich sudden impendin g joint overload or pain stim uli are tran sm itted th rough a reflex arc an d cause the quadriceps to stop firing. Asecond reason for givin g way is actual quadriceps weakn ess. Givin g way can also occur with in stability. Th e m ost com m on cause of in stability is patellar instability with lateral patellar subluxation or dislocation. ACL-deficien t kn ees can also sublux an d give way with twistin g, turnin g, or cuttin g m ovem ents. 7. Has th e kn ee “locked’’? Locking is a very specific phenom enon an d generally reflects m en iscal path ology or a loose body, such as a displaced osteochondral fracture fragm en t. Lockin g implies a tran sien t in ability to flex or extend the knee, lastin g from m inutes to days. Gen erally th e kn ee is fixed in 10 to 20 degrees of flexion an d can n ot be straigh ten ed. Episodes m ay occur spontan eously or follow a twist or squat. In locked kn ees with a torn m en iscus, the m eniscus is usually torn and subluxed within th e joint in th e configuration of a bucket handle. Som e patients com plain of lockin g episodes in wh ich th eir kn ee seem s to get stuck for a few secon ds. This has been called “pseudolockin g.’’ Th is can occur for a variety of reasons such as chondral in jury, loose bodies, patellofem oral pain syn drom e, an d syn ovial irritation. During kn ee range of m otion , the typical sm ooth gliding and rotation does n ot occur an d in stead th e kn ee join t surfaces jam togeth er, creatin g a m om entary pause in m otion.

8. What improves the pain? Rest an d activity m odification alm ost always im prove kn ee pain . A red flag sh ould be raised if th e pain is constan t and un related to activities. Con stan t pain sh ould raise con cern for m ore serious problem s such as osteonecrosis, tum or, in fection , th rom boph lebitis, an d n europath ic syndrom es. It is also h elpful to obtain a h istory about previous treatm en t with n on steroidal an tiin flam m atory drugs (NSAIDs), corticosteroid in jections, an d physical therapy to h elp form ulate a treatm en t plan . 9. Does th e pain radiate? In ch ildren , h ip path ology m ay presen t as kn ee pain . In adults, knee pain can radiate from th e hip or low back. Askin g about th e h ip an d back as pain generators can som etim es reveal the true source of th e pain . In addition , radiatin g pain can be th e sign of a neurologic problem such as lum bar sten osis or a peripheral n erve compressive n europathy. 10. How does th e pain in terfere with your activities? Th is in form ation will h elp you form ulate a treatm en t plan . You m ust first un derstan d patien ts’ m otivation an d th eir goals before form ulatin g a treatm en t plan . A seden tary elderly patien t with kn ee pain sh ould be treated differen tly th an a youn g competitive run n er. O n ce you un derstan d h ow this injury affects their work and recreation al lifestyle, you can form ulate th e best treatm en t plan for th em . Th ese 10 question s sh ould be com bin ed with a detailed m edical and surgical history to elucidate any m edical problem s that m ay affect treatm ent course. After a detailed but efficien t h istory, orth opaedists sh ould h ave a lim ited differential diagnosis in place that will allow them to use th e physical exam in ation to determ in e th e correct diagn osis.

Physical Examination Th e physical exam in ation of th e kn ee sh ould in clude a basic kn ee exam in ation com bin ed with special tests based on th e differen tial diagn osis establish ed from th e h istory. A basic knee exam ination sh ould include inspection , palpation , ran ge-of-m otion , an d stability testin g. Th e basic exam in ation is done first, followed by the appropriate special tests.

Inspection Both lower extrem ities should be un dressed com pletely for exam in ation to allow comparison between th e two extrem ities. Observe patients’gait as they walk down the hallway at their norm al caden ce. Note any evidence of pain th at


results in an an talgic gait. In th is gait, m ore tim e is spen t of the unaffected leg durin g the stance phase of gait. Also, note the presence of abnorm al m otion, either from stiffn ess or a varus, valgus, or hyperextension thrust. Observe the patient standing at rest to determ ine the overall alignm en t of the leg. Note the position of the patients’foot’s m edial arch wh ile stan din g. If th e arch collapses or th e foot pron ates, this can negatively affect patellofem oral disorders an d m edial tibial stress syn drom e (sh in splin ts); an orth otic can be effective form of treatm en t for th ese patien ts. Also n ote th e alignm ent of the knee while standing. The norm al align m en t of th e kn ee is 5 to 7 degrees of valgus. Last, evaluate the patients’skin for ecchym oses, erythem a, abrasions, woun ds, an d swellin g. Be certain to in spect th e popliteal fossa to ensure that an occult laceration or abrasion does not escape detection.

Palpation Knee palpation should be system atic so that you do n ot overlook areas of poten tial pain gen erators. First, th e soft tissues and skin should be evaluated for swelling, turgor, integrity, tenderness, or crepitus. If swelling is detected, it m ust be determ ined wh ether th e swelling is in the subcutaneous tissues or a knee join t effusion. A join t effusion can be detected by th e ballottem en t test or th e fluid wave test. Th e ballottem en t test is perform ed with th e kn ee exten ded, first on e h an d m ilks fluid from th e suprapatellar pouch in feriorly into th e knee joint. Then the other hand applies a posterior force to th e an terior aspect of th e patella. Th is force compresses the patella in to the fluid of the knee effusion, and wh en the pressure is released, the patella boun ces back an teriorly. Wh en swellin g is presen t over th e an terior patella an d seem s circum scribed but is n ot ballotable, a prepatellar effusion is presen t an d n ot a join t effusion . Th e fluid wave test can detect a sm aller kn ee join t effusion. In the test, one han d m ilks fluid from th e suprapatellar pouch while th e other h and is positioned so that th e index finger is placed on one side of the patella and the thum b is placed on the other side. Then the thum b is used to apply pressure wh ile th e in dex fin ger is used to detect the transm ission of a fluid wave on th e other side of the join t. Th e fluid wave test is subtle an d requires practice. Next, palpate th e kn ee for soft tissue in tegrity an d th e presen ce of any soft tissue defect. Th is in cludes th e presen ce of an exten sor m ech an ism disruption . Palpate th e quadriceps tendon superior to the superior pole of the patella for defects an d th en palpate th e patellar ten don in ferior to th e inferior pole of the patella for defects. Th en palpate th e kn ee for ten dern ess. Th is is th e m ost fam iliar part of th e kn ee exam in ation an d requires exact knowledge of the anatomy of the knee and attention to detail. Th e kn ee sh ould be palpated from proxim ally to distally in a system atic m an n er to en sure com pleten ess. Diagnostic accuracy and patient com fort can be improved by exam in in g less sym ptom atic areas first for reassuran ce an d dem on stration of in ten ded gen tlen ess of th e exam in ation .

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Exam ination of the patien t’s countenance durin g the exam in ation will often improve th e exam in ation reliability. An teriorly, palpate th e exten sor m ech an ism , in cludin g the rectus fem oris, vastus lateralis, vastus m edialis, the retin aculum , patella, patella ten don , an d th e tibial tubercle. Medially, palpate th e m edial epicon dyle, m edial join t lin e, course of the superficial MCL, MCL insertion, pes tendons, an d pes in sertion . Laterally, palpate th e lateral epicon dyle, lateral join t lin e, course of th e LCL, LCL in sertion , fibular h ead, an d Gerdy tubercle. Palpate both join t lin es from an terior to posterior. Palpate th e m edial an d lateral patella facets by subluxing the patella to the m edial or lateral side to facilitate palpation of its deep surface. Palpate posteriorly in th e popliteal fossa for ten dern ess or a m ass. Last, palpate the knee for crepitus. Crepitus refers to a gratin g sensation that is felt by placing on e’s hand over th e patellofem oral join t wh ile th e patien t actively exten ds th e kn ee. Alth ough crepitus is n ot n ecessarily path ologic, th e presen ce of crepitus sh ould be com pared with th e opposite side. Crepitus can be suggestive of patellofem oral arth ritis.

Range of Motion Th e n orm al ran ge of m otion of th e kn ee in flexion an d exten sion is 0 to 140 degrees, but 5 to 10 degrees of hyperexten sion is often possible. Wh en th e kn ee is flexed at 90 degrees, passive rotation of th e tibia on th e fem ur can be dem on strated up to 25 or 30 degrees. Th e degree of passive rotation varies from patient to patient. However, the am ount of internal rotation always exceeds that of extern al rotation . Wh en the knee is fully exten ded, n o rotation is possible. Sagittal displacem ent of the tibia on th e fixed fem ur is detectable in both the anterior and posterior directions when the kn ee is flexed. Th e norm al exten t of sagittal displacem en t sh ould n ot exceed 3 to 5 m m . Wh en th e kn ee is extended, lateral (abduction –adduction ) m otion at th e knee join t occurs to a lim ited exten t and should not exceed 6 to 8 degrees. With th e kn ee hyperexten ded, n o lateral m otion sh ould be present. With the kn ee flexed, lateral m otion is possible but should n ot exceed 15 degrees. Th e ran ge of m otion of th e kn ee join t sh ould be com pared with th at of th e opposite, un in jured kn ee. Ran ge of m otion of the knee should be evaluated both actively and passively. Loss of flexion is n on specific, an d it is seen in n early every situation wh ere th e kn ee is pain ful. It is im portan t to pay careful atten tion to th e loss of exten sion as it can h elp narrow th e differen tial. The different degrees of active and passive m otion can in dicate possible pathology. 1. Decreased active an d passive m otion Th is m otion is likely due to som e type of m ech an ical block with in th e kn ee. Mech an ical blocks with in the kn ee can include a joint effusion, a displaced bucket h an dle m en iscus tear, an ACL stum p (cyclops lesion), and a loose body (ch ondral fragm en t). Pain can also lim it both active an d passive

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m otion. In degenerative arth ritis, a flexion contracture can form as the knee loses both active an d passive extension. The loss of extension in the arthritic knee occurs from both pain an d recurrent effusion th at even tually results in tigh ten in g of th e posterior capsule. 2. Decreased active but norm al passive m otion Th is m otion is likely due to path ology in volvin g th e exten sor m ech an ism such as quadriceps ten don rupture, patella fracture, or patella tendon rupture. In addition , in jury to th e kn ee can cause reflex quadriceps in h ibition , causin g an in ability of th e quadriceps to actively con tract with m ain tain ed passive m otion . Quadriceps in h ibition gen erally resolves with tim e or with resolution of th e join t effusion . A fem oral n erve lesion would also preven t quadriceps con traction and decrease active m otion with n orm al passive m otion. One way to compare lack of extension is with heel height differen ce. Th e patien t is placed pron e, an d th e h eigh t differen ce of the affected heel is compared with th e un affected contralateral heel. Each cen tim eter of h eigh t difference is rough ly equivalen t to 1 degree of loss of exten sion . Th e degree of extension can also be m easured with a goniom eter an d compared between th e kn ees.

Ligament Evaluation Th e exam in ation of th e kn ee ligam en ts can be on e of th e m ost difficult aspects of th e kn ee physical exam in ation . It is importan t to evaluate th e un in volved kn ee for comparison as th is can be con sidered th e n orm al degree of laxity for the patient in m ost cases. In general, ligam ent evaluation in volves stressin g th e join t in th e direction th at is usually protected by th e specific ligam en t in question . In addition , the ligam ent’s origin, m idsubstance, and insertion should be palpated if possible. Th e four m ajor kn ee ligam en ts are the MCL, ACL, PCL, and LCL. Ligam en t in juries are graded accordin g to I-to-III (m ild, m oderate, severe) classification scale. Atype I (m ild) sprain in volves ligam en t in jury with out detectable laxity an d a solid endpoint. A type II (m oderate) sprain involves m inim al laxity with a soft en dpoin t an d represen ts a partial disruption . A type III (severe) sprain in volves com plete disruption of th e ligam en t with out an en dpoin t. In jury is determ in ed by th e followin g: 1. Th e am ount of “opening’’ compared with the opposite side, m easured in either degrees or m illim eters. 2. Th e abn orm al quality of th e en dpoin t with a soft feel upon application of stress rath er th an a firm or discrete en dpoin t. 3. Th e reproduction of sym ptom s, usually pain with stress testin g.

Th e MCL is th e m ost com m on ly in jured ligam en t of th e knee. The MCL prevents valgus m ovem ent of the knee. Alth ough its course can be traced from th e m edial epicon dyle of th e fem ur to th e proxim al m edial tibia, it can n ot be palpated. However, ten dern ess to palpation alon g th e course of th e ligam en t does correspon d to th e site of th e tear. In tegrity of th e MCL is tested by applyin g a valgus stress to th e sligh tly flexed kn ee, 15 to 30 degrees. Th e patien t is placed supin e with th e kn ee sligh tly flexed off th e table. One hand applies a m edial force to the distal fem ur an d on e h an d grabs th e distal tibia an d applies a lateral force to it (Fig. 17.12). The degree of opening and the endpoint is evaluated. In jury to th e MCL leads to both pain an d open ing of th e knee when a valgus stress is applied. Th e ACL is th e n ext m ost com m on in jured ligam en t of th e kn ee. Th e ACL preven ts an terior tran slation of th e tibia on th e fem ur. Physical exam in ation of th e ACLis m ore difficult th an th e MCL because it can n ot be palpated. Th e m ain exam in ation s for th e ACL are th e Lach m an test, th e an terior drawer test, an d th e pivot sh ift test. Th e Lach m an test is th e m ost sen sitive test for an ACL tear. It is perform ed with th e patien t supin e an d th e kn ee flexed 15 to 30 degrees off th e edge of th e table. Th e fem ur is h eld securely in on e h an d an d th e tibia is firm ly grasped with th e oth er hand, and an attempt is m ade to translate the tibia an teriorly (Fig. 17.13). The test is positive if th e tibia tran slates anteriorly greater th an th e con tralateral side or sh ows an abn orm al endpoin t. Generally the Lach m an test is n ot painful. False n egatives can occur if th e patien t’s leg m usculature is not relaxed, and it m ay help to put a pillow behind th e patien t’s kn ee before perform in g th e exam in ation . Th e an terior drawer test is less sen sitive th an th e Lach m an test. In th is test, th e kn ee is flexed to 90 degrees with th e patien t supin e. While th e foot is fixed, usually with the exam iner sittin g on it, both han ds grasp th e proxim al tibia and attempt to tran slate it an teriorly. As with th e Lach m an test, th e test is positive if th e tibia tran slates an teriorly greater th an th e con tralateral side or sh ows an abn orm al en dpoin t. Th e anterior drawer test is generally less reliable because of pain, swelling, an d h am strin g spasm . The pivot sh ift test is the m ost specific ACLtest. This test evaluates th e ACL’s function on both an terior an d rotation al kn ee stability. Th e patien t is placed supin e and the foot is grabbed and intern ally rotated. Usin g th e h eel of th e opposite h an d, a valgus stress is applied to th e proxim al tibia as the kn ee is flexed from an exten ded position . Because th e ACL-deficien t kn ee is subluxed anterolaterally in th e extended position, it reduces with a palpable an d a visible clun k at 30 degrees of flexion . Th e clun k occurs as th e IT ban d becom es a kn ee flexor at 30 degrees an d reduces th e tibia posteriorly. Th e pivot sh ift test dem on strates fun ction al in com peten ce of th e ACL. Th ese patien ts are at risk for kn ee subluxation durin g cuttin g or twisting m ovem ents. This test is difficult to perform on awake, alert patien ts an d often can be perform ed on ly on ce because it produces an un com fortable in stability sen sation and pain. Therefore, th e test is com m only used in th e


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Figure 17.12 Test for varus and

valgus laxity at 0◦ and 30◦ of knee flexion. (Redrawn from Tria AJ, Klein KS. An Illustrated Guide to the Knee. New York: Churchill Livingstone, 1992, with permission. Reproduced with permission from Chapman MW, Szabo RM, Marder R, et al.: Chapman’s Orthopaedic Surgery, 3rd ed. Philadelphia: Lippincott Williams & Wilkins, 2001.)

A

operation room after th e in duction of gen eral an esth esia to verify th at th e ACL is fun ction ally in competen t prior to ACL reconstruction graft harvest/preparation. Th e PCLis in jured less frequen tly th an th e ACL. Th e PCL preven ts posterior tran slation of th e tibia on th e fem ur. Th e PCL is exam in ed with th e sag sign , th e posterior drawer test, an d th e quadriceps active test. Th e sag sign , “Godfrey test,’’ is observed with the patient supine and the knee flexed to 90 degrees. The am ount of posterior displacem en t of th e tibia on th e fem ur in th is position is compared with the con tralateral kn ee. Th e posterior drawer test is th en perform ed. First, th e tibia is reduced from its posteriorly subluxed position. Then both hands

Figure 17.13 The Lachman test, per-

formed at 30◦ of knee flexion, is the most sensitive test for integrity of the ACL. (Redrawn from Tria AJ, Klein KS. An Illustrated Guide to the Knee. New York: Churchill Livingstone, 1992, with permission. Reproduced with permission from Chapman MW, Szabo RM, Marder R, et al.: Chapman’s Orthopaedic Surgery, 3rd ed. Philadelphia: Lippincott Williams & Wilkins, 2001.)

B

are used to force th e proxim al tibia posteriorly. Th e am oun t of tran slation an d th e en d poin t are evaluated (Fig. 17.14). Th e quadriceps active test can also be perform ed in this position with th e patien t supin e an d th e kn ee flexed to 90 degrees. The exam iner sits on the patient’s foot to preven t exten sion of th e kn ee. Th en th e am oun t of posterior sag is n oted, an d th e patien t is asked to attempt to straigh ten out th e leg. The contraction of the quadriceps reduces th e posteriorly subluxed tibia. Th e LCL is th e least com m on ly in jured kn ee ligam en t. Th e LCL prevents varus m ovem en t of th e kn ee. Th e ligam en t can be palpated for ten dern ess alon g its course from the lateral epicondyle to the h ead of the fibula. The LCL

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Figure 17.14 The posterior drawer test, performed at 90 degrees of knee flexion. (Reproduced with permission from Chapman MW, Szabo RM, Marder R, et al. Chapman’s Orthopaedic Surgery. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2001.)

is best palpated in th e figure-of-four position . Testin g for ligam en t in tegrity is perform ed by placin g a varus stress on the sligh tly flexed knee, 15 to 30 degrees. Th e degree of open in g an d th e en dpoin t are evaluated.

exact area of ten dern ess is importan t wh en form ulatin g a proper treatm en t plan . Th e presen ce of m edial facet ten dern ess is th e m ost com m on location of pain in patien ts with patellofem oral pain syn drom e. Patien ts with symptom atic

Strength Stren gth assessm en t sh ould be con ducted to determ in e m uscle or n erve in jury. Ask th e patien t to perform a straigh t leg raise, liftin g th e leg off of th e exam in ation table. He or sh e m ay not be able to do this owin g to pain, swellin g, an d appreh en sion , but th e ability to do so con firm s fun ction of th e fem oral n erve an d th e exten sor m ech an ism . If addition al abn orm alities are suspected, th en a th orough neurom uscular exam ination of the lower extrem ity sh ould be perform ed. Patellofemoral Joint Assessment Exam ination of the patellofem oral joint begins with inspection, n oting the dynam ic gait, including the feet for pron ation . Th e presen ce of pron ation is a com m on accompanim ent of patellofem oral pain syndrom e. The exam in er th en in spects for atrophy with particular atten tion to quadriceps developm en t. Th e vastus m edialis obliquis (VMO) at th e superom edial border of th e patella stron gly in fluen ces patellar trackin g. Havin g th e patien t try to push the back of the kn ee in to the exam ination table while lyin g supin e allows for observation of VMO developm en t. Next, m alalign m en t is assessed. Patellofem oral pain due to m alalign m en t an d th at due to patellar in stability are two frequen t clin ical problem s in wh ich abn orm al patella position in g or trackin g plays a role. Th e quadriceps an gle (Q an gle) is m easured; th is an gle is m ade by a lin e from the ASIS to th e m idpatella, intersectin g a line from the m idpatella to th e patella ten don in sertion at th e tibial tubercle. Th e n orm al an gle is approxim ately 15 degrees but is gen derdepen den t, with fem ales h avin g a greater an gle th an do m ales. Q an gles greater th at 15 degrees con tribute to patella m altrackin g an d m alalign m en t (Fig. 17.15). The exten sor m echan ism is palpated for tenderness, in tegrity, an d crepitus. Palpation sh ould in clude th e m edial an d lateral patellar facets an d retin aculum . Iden tifyin g th e

Figure 17.15 Q angle measured in full extension. In men, Q an-

gles greater than 10 degrees and, in women, Q angles greater than 15 degrees are associated with patellofemoral disorders. (Reproduced with permission from Chapman MW, Szabo RM, Marder R, et al.: Chapman’s Orthopaedic Surgery, 3rd ed. Philadelphia: Lippincott Williams & Wilkins, 2001.)


bipartite patella m ay h ave ten dern ess localized to th e nonunited fragm ent. Alternatively, som e patien ts with radiograph ically eviden t abn orm al ossification cen ters will have n o localized ten dern ess. Irregular ossification or scar tissue form ation m ay lead to n odularity within the patellar ten don . Prom in en ce of th e tibial tubercle at th e site of th e patella ten don in sertion , with or with out ten dern ess, m ay be presen t due to O sgood Sch latter syn drom e. Som e exam iners have described the patellofem oral compression test as a useful in dicator of patellofem oral pathology. The test involves the gentle application of a compressive force to the patella in to th e troch lear groove, attemptin g to elicit pain that reproduces patients’symptom s. This test is nonspecific, as discom fort is frequen tly elicited as a result of painful im pin gem en t of th e h igh ly in n ervated syn ovial lin in g. Next, th e exam in er in spects an d palpates for patella alignm ent and tracking. Th e patella glide test is perform ed on a supin e patien t with th e legs relaxed. Th e patella is translated both m edially an d laterally while noting the degree of tran slation an d th e am oun t of soft tissue restrain t at th e extrem es of tran slation . Norm ally, the patella can be sligh tly translated both m edially an d laterally. Restriction m ay be norm al for that patient, so it m ust be compared with the opposite side. Failure to translate the patella m edially durin g th e patellar glide test m ay suggest lateral patellar retin acular tigh tn ess. Tran slation of m ore th an 50% of th e patella’s width laterally suggests m edial retin acular laxity. In creased laxity in both m edial an d lateral tran slation suggests th e possibility of gen eralized ligam en tous laxity. Th e patellar tilt test is also perform ed on a supin e, relaxed patient. An attempt is m ade to evert the patella by lifting up its lateral side (Fig. 17.16). Norm ally th e patella can evert at least to neutral. Failure to elevate th e lateral side to approxim ately 15 degrees suggests a tigh t lateral retin aculum an d is th e m ost com m on physical fin din g in patien ts with patellofem oral pain syn drom e. Maltrackin g is evaluated by in spection of th e patella. First, th e exam in er observes th e restin g position of th e patella wh en th e patien t is seated. If th e patella is orien ted laterally from m idline an d looks like “grasshopper eyes,’’ it is suggestive of patellar instability. Next, the seated patient should extend the knee. The course the patella as it tracks from flexion to term inal exten sion is followed. Norm al excursion of th e patella in volves tracking in m ultiple plan es, an d its course is n ot sim ply direct superior tran slation. Slight m edial to lateral m ovem ent an d subtle rotational m ovem ent m ay accompany n orm al patella tracking. Th e asymptom atic kn ee is useful for comparison . Th e “J’’ or “jum p’’sign can som etim es be observed in patien ts with patellofem oral in stability, in wh ich th e patella actually is seen to “jum p’’ at approxim ately 20 degrees of flexion as it reduces in to the trochlear groove from its laterally subluxed position. The course that th e patella tracks takes on the sh ape of an inverted “J.’’Slight lateral excursion during term in al exten sion m ay be n orm al, especially if presen t bilaterally.

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Figure 17.16 A positive patella tilt test is defined as inability to

lift the lateral facet of the patella more than 15 degrees (or to neutral) and indicates a tight lateral retinaculum. (Reproduced with permission from Johnson DH and Pedowitz RA: Practical Orthopaedic Sports Medicine and Arthroscopy. Philadelphia: Lippincott Williams & Wilkins, 2006.)

Patellar in stability assessm en t sh ould also in clude an exam in ation for appreh en sion . Th e patella appreh en sion test is perform ed with th e patien t supin e an d relaxed. Gen tle pressure is applied to th e patella to laterally tran slate th e patella wh ile observin g th e patien t’s coun ten an ce. Th e patient m ay becom e an xious an d/ or actually implore th e exam in er to discon tin ue th e m an ipulation because of th e feeling of impending instability.

Radiographic Analysis Plain Radiography Radiograph s are h elpful as an adjun ct to a kn ee exam in ation, particularly in the traum atized patient. In the absence of traum a, patien ts do n ot always require radiograph ic evaluation , particularly wh en th e diagn osis is clin ically apparent. Patients with persistent symptom s unresponsive to treatm ent, those with a h istory of acute or traum atic on set, an d th ose with physical exam ination fin dings suggestive of m echan ical or structural pathology (m alalign m ent, crepitus, restricted m otion , an d loss of in tegrity) deserve radiograph ic evaluation .

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The standard radiograph s of the knee are a th ree-view series consisting of anteroposterior (AP), lateral, an d a patellofem oral view. Th e AP view sh ould be taken durin g weigh t-bearin g to facilitate detection of m alalign m en t or join t space n arrowin g. Both kn ees sh ould be im aged for comparison. The AP should also be in spected for soft tissue abnorm alities, bone density, an d joint height. The lateral view can be taken while non –weigh t –bearin g, with th e kn ee flexed at 30 degrees. The patellofem oral join t can be evaluated on th e lateral view alon g with th e patellar h eigh t. Th e patellofem oral view (also kn ow as th e sunrise, Merchant, or Laurin view depen din g on th e im agin g tech n ique used) dem on strates th e relation sh ip between th e patella an d the fem ur’s trochlear groove. Th e patellofem oral view can dem onstrate patellofem oral join t space narrowing, osteophytes, an d m altrackin g. Num erous oth er kn ee radiograph s h ave been described, including th e tunn el view, the posteroan terior (PA) flexion weigh t-bearin g view, oblique join t views, an d specific views to evaluate th e tibial plateau. Th e tun n el view is obtain ed by directing th e x-ray beam into the in tercondylar notch or tun n el, with th e kn ee flexed at 30 degrees. Th e kn ee flexion angle allows visualization of n ot on ly th e intercondylar notch but also the posterior aspect of the fem oral condyles. Lesions located m ore posteriorly on the fem oral condyles, such as osteoch on dritis dissecan s (O CD) lesions or osteon ecrosis, m ay be seen on ly on th is view. Likewise, osteoch on dral fragm en ts with in th e kn ee m ay be m ore readily detected with th e kn ee flexed. Th e weigh t-bearin g PA view is taken in 30 degrees of flexion and dem on strates joint lin e narrowing earlier th an the conventional weight-bearing AP view.

Computed Tomography Computed tom ography (CT) scan s are routin ely used to evaluate patien ts with distal fem ur or proxim al tibia fractures as an adjun ct to radiograph s. Fin e-cut (2 m m ) CT scan s with sagittal an d coronal reconstruction s provide excellen t bony detail of the joint surfaces and allow dem onstration of the degree of articular in volvem en t and displacem en t. CT scan s can also be of use in cases of patellofem oral m alalign m en t to better visualize th e bony articulation of the patellofem oral joint. CT scan s are preferred over MRI for evaluation of bone. They are less helpful in the evaluation of kn ee soft tissue path ology. Magnetic Resonance Imaging MRI scan s are un n ecessary in th e evaluation of m ost kn ee in juries. However, wh en in dicated, th ey are h igh ly sen sitive an d specific for th e diagn osis of soft tissue in juries of the kn ee. Most com m only, they are used to diagnose or confirm the diagnosis of knee ligam entous and m eniscus in juries. Kn ee MRI h as been sh own to be 90% to 100% sen sitive an d specific for th ese indications. MRI is also useful in detectin g tibial stress fractures an d n eoplasm s. MRI is highly sensitive and specific for knee path ology; however,

it is expensive and requires a patient to be cooperative and rem ain m otion less durin g th e exam in ation . Despite th ese lim itations, it rem ains the “gold standard’’ for soft tissue injuries within and surrounding the knee.

Bone Scan Som e con dition s are n ot visible usin g con ven tion al plain radiograph s. Th ree-ph ase tech n etium bon e scan s are used to detect areas of in creased vascularization an d bon e turnover. However, bone scans are nonspecific. They are used to evaluate patien ts with sh in splin ts. In creased focal uptake con firm s th e presen ce of a stress fracture, wh ereas diffuse uptake suggests m edial tibial stress syn drom e with out fracture. Bon e scan is ch eaper th an MRI; but it is less specific an d requires contrast injection.

Arthroscopy Th e gold stan dard for diagn osis of in traarticular path ology is knee joint arthroscopy. Introduced for clinical applications in the late 1970s, this m odality has developed into a tool for diagn osis an d im m ediate treatm en t for th e m ajority knee pathology. Arthroscopy is a m inim ally invasive techn ique th at is perform ed through two or th ree sm all, 1-cm , incisions. A fiber optic cam era is placed within the kn ee, allowing visualization of the entire knee join t. Intraarticular pathology can be diagnosed, and th en m iniature instrum en ts can be used to perform im m ediate treatm ent. Studies h ave sh own decreased m orbidity (pain , stiffn ess, infection , n erve injury) when compared with open arth rotom y. In addition , th e m agn ification afforded by th e fiber optic len s tech n ology allows for superior visualization of th e kn ee join t compared with con ven tion al open tech n iques. Diagn ostic arthroscopy is expen sive an d in vasive an d, therefore, sh ould be utilized on ly wh en oth er m ore conservative m easures of diagnosis an d treatm ent h ave failed.

TRAUMATIC INJURIES OF THE KNEE Distal Femur Fractures Distal fem ur fractures accoun t for approxim ately 7% of all fem ur fractures. There is a bim odal age distribution effecting young adults and osteoporotic elderly individuals. Fractures of th e distal fem ur m ay occur in eith er th e supracon dylar or th e in tercondylar region an d are often in traarticular. Th eir m anagem ent is som etim es difficult, owing to fracture displacem ent and associated soft tissue in jury.

Classification Several classification system s exist, of wh ich perh aps th e m ost used is the AO/ ASIF classification. It divides the fractures according to whether they are intraarticular or extraarticular. Type A is extraarticular, B is unicondylar, and C is intraarticular. In addition , there are several subtypes that are beyon d th e scope of this chapter.


Mechanism of Injury Most fractures occur as a consequence of direct traum a. As m en tion ed previously, there is a bim odal age distribution based on th e m ech an ism of in jury. Youn ger patien ts h ave complex, intraarticular fractures as a result of h igh -energy traum a, often, a m otor vehicle accident or a fall from height. Older, osteoporotic patients frequently have m ore simple extraarticular fractures th at result from a m in or fall from stan ding on to a flexed knee. Presentation Patients generally present with localized pain, deform ity, an d inability to bear weight. Approxim ately 5% to 10% of all distal fem ur fractures are open injuries. Relevant Anatomy Th e gastrocn em ius m uscle origin ates on th e m ost distal portion of th e fem oral con dyles. Th e pull of th e gastrocn em ius m uscle on the distal piece causes the usual posterior displacem en t an d an gulation at th e fracture site. Th e pull of the quadriceps and ham strin gs m uscles lead to shorten ing at the fracture site. Physical Examination Pain ful swellin g an d deform ity present over the distal fem ur, often accompan ied by false m otion at the fracture site. Th e proxim ity of neurovascular structures to th e fracture site m andates prompt assessm ent of the neurovascular status of the lim b. Fullness in the popliteal space accom pan ied with weak distal pulses suggests vascular in jury.

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Radiographic Examination Radiograph s sh ould in clude AP, lateral, an d two oblique projection s of th e kn ee. In addition , two views of th e h ip sh ould be obtain ed to evaluate the fem oral neck. Special Tests CT scans are gen erally perform ed to evaluate the am ount of in traarticular in volvem en t an d displacem en t. Differential Diagnosis Th e diagn osis is easily m ade if deform ity is presen t an d good radiographs are obtained. Th e differential includes fem oral shaft fracture, tibial plateau fracture, an d kn ee dislocation. Treatment Non operative treatm en t is possible in extraarticular an d n on displaced in traarticular fractures. Non operative treatm ent consists of fracture reduction an d casting or functional bracin g. For displaced fractures, traction is gen erally n eeded to obtain and m ain tain reduction . Non operative treatm ent of these fractures often requires traction for 6 to 12 weeks, so m ost displaced distal fem ur fractures are treated operatively with or without in itial tibial pin traction . Articular compon en ts of th e fracture are repaired with in terfragm entary screws. Th e fractures are then fixed stabilized with a lateral plate an d screws, in tram edullary (IM) n ail, or extern al fixator. Lateral plates can be in serted with con ven tional open m ethods or via newer, m inim ally in vasive tech n iques (Fig. 17.17). Th e plates can be 95-degree con dylar

Figure 17.17 (A) AP and (B) lateral radiographs

demonstrating locking plate fixation of a distal femur fracture. (Reproduced with permission from Bucholz RW, Heckman JD, Court-Brown C, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)

A

B

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plates, dyn am ic con dylar screw plates, or con toured periarticular plates with lockin g or n on lockin g screws. IM n ails are lim ited to extraarticular distal fem ur fractures, with th e fracture at least 5 cm superior to the joint line. The m ain lim itation of IM n ails is ach ievin g adequate fixation of th e distal fragm en t. IM n ails can be in serted an terograde or retrograde. Retrograde IM n ails h ave improved distal fixation with m ultiple distal interlockin g screws at m ultiple an gles. External fixation devices are generally used as a part of dam age con trol orth opaedics with distal fem ur fractures; however, hybrid fram es using fine-wire fixation distally an d half-pin fixation proxim ally can be used for definitive treatm en t. Postoperatively, weigh t-bearin g is in itially delayed, but early ran ge of m otion of th e kn ee is en couraged to decrease stiffn ess. Weigh t-bearin g is advan ced with radiograph ic eviden ce of h ealin g at 6 to 12 weeks.

Complications Th e m ost com m on complication of distal fem ur fractures is kn ee stiffn ess, an d th erefore, ran ge-of-m otion exercises are started early. Non un ion is rare, given th e rich vascular supply of th e cancellous bone of the distal fem ur. Varus m alun ion is th e m ost com m on deform ity. Posttraum atic osteoarth ritis results from failure to restore articular con gruity an d altered kn ee biom ech an ics, as well as ch on dral dam age at th e tim e of th e in jury. In fection is greater with a high-energy m echan ism and open injuries.

Tibial Plateau Fractures Tibial plateau fractures con stitute approxim ately 1% of all fractures.

Classification Th ere are several classification system s, th e on e th at is m ost utilized is th e Sch atzker classification , wh ich divides th e plateau fractures accordin g to th eir pattern , location , an d level of traum a (Fig. 17.18). In type I, there is a split frac-

ture of th e lateral tibial plateau. Type II involves a split with associated depression of th e lateral plateau. In type III, th e lateral plateau is depressed. Type IVfractures in volve a split, depression, or com bination of both of the m edial plateau. Type V fractures are bicon dylar, in volvin g both th e m edial an d lateral plateaus. Th e type VI fractures exten d proxim al in to th e m etaphysic of th e tibia, causin g dissociation between the m etaphysis and diaphysis of th e proxim al tibia. Generally, types I to III are low-energy injuries, and types IV to VI are high-en ergy injuries.

Mechanism of Injury Th e m ech an ism of in jury is a varus or valgus load about the knee coupled with an axial load. Motor vehicle acciden ts accoun t for th e m ajority of in juries in youn ger patients; however, in older patients, this injury m ay occur with a simple fall. Th e quality of th e patien t’s bon e an d the degree of force applied determ ine the type of fracture an d the presence of associated ligam entous injuries. With a h igh -en ergy varus or valgus load to th e kn ee, eith er th e collateral ligam ent will tear or the plateau will fracture. Th e weaker structure will fail. In youn ger patien ts with stron g, rigid bon e, th ere is a h igh in ciden ce of split-type fractures an d a h igh rate of associated ligam ent injuries. In older patients, with bone that is weaker, there is a higher incidence of depression -type fractures an d a lower in ciden ce of ligam ent injuries. Type V bicondylar split fractures involve a h igh -en ergy axial load applied to an exten ded kn ee. Presentation Patients present with severe kn ee pain an d swelling following m ajor traum a to th e kn ee due to a m otor vehicle, industrial, or ath letic accident. The patient typically cannot bear weigh t on th e extrem ity. Tradition ally, th ese in juries were called “bumper injuries’’ to describe the com m on m echan ism of th e fracture occurrin g to th e kn ee of patien ts who stepped out into traffic and their knee was struck by a car’s bumper.

Figure 17.18 Schatzker’s classification of tibial plateau fractures is shown. Types I to IV are defined

as follows: I: A split fracture of the lateral tibial plateau. II: A pure depression fracture of the lateral tibial plateau. III: A split-depression fracture of the lateral tibial plateau. IV: A fracture of the medial tibial plateau. V: A bicondylar fracture of the tibial plateau. VI: A fracture of the tibial plateau with metaphyseal-diaphyseal dissociation. (Reproduced with permission from Chapman MW: Chapman’s Orthopaedic Surgery, 3rd ed. Philadelphia: Lippincott Williams & Wilkins, 2001.)


Relevant Anatomy Th e tibial plateau is composed of m edial an d lateral con dyles. The m edial condyle is larger and concave from an terior to posterior an d m edial to lateral. The lateral plateau is sm aller in size an d con vex in sh ape. Th e plateaus are separated by an intercondylar em inence that serves as an attachm ent for the ACL. Because the m edial articular surface and its associated condyle is stronger th an the lateral plateau, an d because of th e n orm al valgus an gle of th e knee, fractures involving the lateral compartm ent are m ore com m on. Adjacen t soft tissue an d n eurovascular structures are at risk in these in juries, particularly those that involve exten sive com m in ution an d a h igh er-en ergy in jury. Th e popliteal vessel trifurcates just below th e kn ee an d is at risk with proxim al tibial fractures. Laterally, th e peron eal n erve is at risk as it winds around the n eck of the fibula. Physical Examination Swellin g an d ecchym oses are frequen tly presen t an d m ay be severe. Neurovascular assessm en t is critical, particularly in cases of high-energy traum a. Evaluation for stability is an important component in determ in ing the treatm ent. This involves the application of gen tle stresses to the knee to determ in e th e degree of stability. With th e kn ee in exten sion , a varus or valgus force is applied, depending on the com partm en t in volved, an d th e ten den cy for th e join t lin e to “open up’’is determ ined. Sim ilarly an an terior or posterior force m ay be gently applied to determ in e the presence of associated cruciate ligam ent in jury. Pain often precludes a satisfactory evaluation , which requires intraarticular local an esth etic or general anesthesia. Radiographic Examination AP, lateral, and oblique radiograph s of the knee are required. Special Tests Varus and valgus stress radiographs are som etim es helpful to establish the stability of an injury an d assess for associated ligam entous dam age. This som etim es requires an esth esia an d can be perform ed under fluoroscopy. CT scans are helpful to determ ine th e degree of intraarticular displacem en t. Because m an agem en t often h in ges on th e am ount of fracture displacem ent, CT scans are com m only indicated in the workup of tibial plateau fractures. Differential Diagnosis Because knee dislocations m ay be accom panied by a tibial plateau fracture, on e m ust con sider th e possibility wh en evaluatin g any patien t with distal fem oral or proxim al tibial traum a. The relatively h igh percentage of vascular injuries m andates the consideration in any knee traum a. There are a n um ber of com m on ly associated in juries accompanyin g fractures of the tibial plateau. Th ese include m eniscus tears in up to 50% and associated ligam ent injury in up to 30%.

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Youn g patien ts with stron g bon e are at a h igh er risk for ligam en tous in jury.

Treatment Non operative treatm en t m ay be sufficien t for n on - or m in im ally displaced fractures and th ose th at are “stable.’’Treatm ent m ost com m on ly involves non –weigh t-bearing in a fracture brace for up to 3 m onths. Operative intervention is reserved for displaced (usually greater than 5 m m articular incongruity), unstable, or open fractures. Surgical treatm ent m ost com m only consists of open reduction and intern al fixation (ORIF) with a con toured proxim al tibia locking plate or an extern al fixator in patien ts with severe swellin g and fracture blisters. Vascular injuries usually require repair. Nerve in juries are usually n europraxias. Wh en treatin g an open in jury or perform in g an ORIF, n erve exploration m ay be warran ted. A h igh in dex of suspicion for th e developm ent of compartm ent syn drom e should be m aintained. Complications Complications include stiffness, m alunion, nonunion, posttraum atic osteoarth ritis, in fection , compartm en t syn drom e, an d n erve in jury.

Patella Fractures Fractures of the patella are relatively com m on, accountin g for 1% of all skeletal injuries. They are m ore com m on in m en than in wom en (2:1). They can occur in all age groups, but th e m ost com m on age group is 20 to 50 years of age.

Classification Patella fractures are divided in to n on displaced an d displaced pattern s. In addition , th ey can be described on th e basis of fracture location an d pattern : stellate, com m in uted, tran sverse, vertical, polar (superior or in ferior), or osteoch on dral (Fig. 17.19).

Undisplaced

Transverse

Multifragmented displaced

Lower or upper pole

Vertical

Multifragmented undisplaced

Osteochondral

Figure 17.19 Classification of patella fractures. (Reproduced with permission from Bucholz RW, Heckman JD, Court-Brown C, Tornetta P. Rockwood and Green’s Fractures in Adults, 6th Ed. Philadelphia: Lippincott Williams & Wilkins, 2005.)

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Mechanism of Injury Th e m ost com m on m ech an ism is in direct, from a forced eccentric con traction of th e quadriceps as the knee is flexed. Th e in trin sic stren gth of th e patella is exceeded by th e pull of th e exten sor m ech an ism . Th e facture is gen erally tran sverse with variable in ferior pole com m in ution . Th e degree of displacem en t is based on th e degree of retin acular disruption . Patella fractures can also occur th rough direct traum a from a fall directly on th e patella. Direct traum a results in a stellate or com m in uted fracture pattern with preservation of th e retin aculum . Presentation Patien ts present with acute anterior knee pain accompan ied by localized tenderness and swelling. Relevant Anatomy Th e patella is th e largest sesam oid bon e in th e body. Th e patella in creases th e m ech an ical m om en t arm of th e quadriceps an d protects th e fem oral con dyles from direct traum a. Th e articular cartilage of th e patella is th e th ickest in th e body an d can be up to 10 m m th ick. Th e m edial an d lateral exten sor retin acula are stron g lon gitudin al expan sion s of the quadriceps an d insert directly on to th e tibia. If th ese rem ain in tact, active exten sion m ay be preserved in the setting of a patella fracture. Physical Examination Patien ts have a tender, swollen, ecchym otic anterior knee. Th e physician m ust evaluate for active exten sion or th e ability to do a straigh t leg raise to determ in e th e in tegrity of retin acula. Radiographic Examination AP, lateral, and sunrise views of the knee are required. Special Tests Special tests are n ot n ecessary. Differential Diagnosis A bipartite patella, in which an ossification center persists, is occasion ally m istaken for a fracture. A bipartite patella alm ost always h as sm ooth superolateral m argin s, an d 50% are bilateral. If a bipartite patella is suspected, con sider im agin g th e con tralateral patella. Quadriceps ten don rupture an d patella ten don rupture sh ould be ruled out by physical exam in ation an d radiograph s. Treatment Non operative treatm en t with eith er a cylin der cast or a knee im m obilizer is reserved for nondisplaced or m in im ally displaced fractures with an in tact exten sor m ech an ism . O perative treatm en t con sists of O RIF or patellectomy. For th e m ost com m on tran sverse fracture pattern , O RIF is perform ed with K-wires or screws placed lon gitudin ally th rough th e patella followed by an an terior

Figure 17.20 AP radiograph demonstrating ORIF of a patella

fracture using tension band fixation and an interfragmentary screw. (Reproduced with permission from Bucholz RW, Heckman JD, Court-Brown C, et al. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)

or circum feren tial ten sion ban d wire (Fig. 17.20). Com m inution is either excised or fixed with interfragm entary screws. Partial patellectomy is perform ed for com m inuted polar fragm en ts with reattach m en t of th e patellar ten don . Total patellectomy is reserved for severe, unrepairable com m inution and is rarely indicated. The retinaculum should be repaired with any type of treatm en t. Postoperatively, th e patien t is weigh t-bearin g as tolerated in a kn ee im m obilizer or cylin der cast for 6 weeks.

Complications Knee stiffness, extensor lag of approxim ately 5 degrees, and exten sor weakn ess are th e m ost com m on com plication s. Posttraum atic osteoarthritis has been shown to occur in up to 50% of patien ts in lon g-term studies. Symptom atic h ardware is com m on an d m ay n ecessitate rem oval after the h ealin g h as occurred. Non un ion an d in fection are rare. Osteon ecrosis occurs with in creasin g com m in ution , but th e m ajority of patients can be treated with observation with spon tan eous revascularization in 2 years.

Quadriceps Tendon Rupture Rupture of the quadriceps ten don is relatively com m on in m iddle-aged patients older than 40 years. The rupture gen erally occurs with in 2 cm of th e superior pole of th e patella. Quadriceps tendonitis or tendin osis is a risk factor and can be caused by an abolic steroid use, local steroid in jection , diabetes m ellitus, in flam m atory arth ropathy, or ch ron ic ren al failure.


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Classification Quadriceps ten don injuries are known as quadriceps strains. Th ey are classified from m ild to severe or grade I to III. A grade III rupture is a complete tear. Th e m ost com m on classification is an incomplete or complete rupture based on th e patien t’s ability to perform a straigh t leg raise or actively exten d th e knee. Mechanism of Injury Th e m ech an ism is th e sam e as th at for an in direct patella fracture, an eccentric load of the quadriceps. In th e case of a quadriceps rupture, th e quadriceps ten don is gen erally weaken ed th rough a degen erative process (ten din osis); an d therefore, it is weaker than the patella an d th us ruptures. Presentation Patients present after experien cing sharp, acute pain after a stum ble or trip. Most are un able to walk because of pain an d in competen ce of th eir exten sor m ech an ism . Th is injury com m on ly occurs in patients 40 to 70 years old, wh ereas patella ten don ruptures are m ore com m on in patients younger th an 40 years. Figure 17.21 Quadriceps tendon repair technique. (Repro-

Relevant Anatomy As discussed in the knee anatomy section, the four quadriceps m uscles becom e tendinous, and coalesce to form the quadriceps ten don . Th ey th en en velop th e patella an d attach distally at th e tibial tubercle as th e patella ten don . Lon gitudin al extensions, the retin acula, run m edial and lateral to th e exten sor m ech an ism an d attach directly on to th e tibia. If retinacula are intact, a patient with a quadriceps rupture m ay still be able to perform active knee exten sion . Physical Examination Th e patien t will h ave swollen , ten der, an terior kn ee. Th e ten dern ess is greatest at th e superior pole of th e patella. A palpable defect is often presen t superior to th e patella. Th e vast m ajority of patients are unable to actively exten d the leg or perform a straight leg raise.

duced with permission from El Attrache NS, Harner CD, Mirzayan R, Sekiya JK: Surgical Techniques in Sports Medicine. Philadelphia: Lippincott Williams & Wilkins, 2006.)

Treatment Non operative treatm en t is reserved for in com plete tears in which active, full-knee exten sion is preserved. Operative treatm ent consists of prim ary repair of the quadriceps ten don to th e superior pole of th e patella. Stron g n on absorbable suture is placed in to the quadriceps tendon with a locked, run ning stitch. The tendon is then reapproxim ated to th e patella through bone tunnels and secured (Fig. 17.21). For chronic ruptures, a quadriceps turndown , Scuderi tech nique, can be utilized for the repair. Postoperatively, the patient is weigh t-bearing as tolerated in a kn ee im m obilizer or cylinder cast for 3 to 4 weeks. At th at point, m otion is started and slowly advanced over the next 6 to 8 weeks with a h in ged kn ee brace.

Radiographic Examination AP and lateral radiographs of th e knee dem onstrate an in tact patella with th e presen ce of patella baja or a low-ridin g patella.

Complications Kn ee stiffn ess, exten sor lag, an d exten sor weakn ess are th e m ost com m on complication s. Rerupture rates are low for acute, prim ary repair.

Special Tests MRI can confirm the tear but is unn ecessary with a positive physical exam in ation . MRI or ultrasoun d can be utilized in inconclusive cases or cases wh ere patient body habitus lim its the physical exam ination.

Patella Tendon Rupture

Differential Diagnosis Th e differen tial in cludes th e two oth er in juries to th e exten sor m echan ism : patella ten don rupture an d patella fracture.

Patella ten don ruptures are less com m on th an quadriceps ten don ruptures an d occur in youn ger patien ts, gen erally th ose youn ger th an 40 years. Th e rupture occurs at th e inferior pole of the patella and is related to degenerative changes with in the patella ten don. Risk factors in clude inflam m atory arthritis, system ic lupus erythem atous, diabetes m ellitus, ch ron ic ren al failure, corticosteroid use, an d chronic patella tendonitis.

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Classification Patella tendon ruptures can be classified by location of the rupture: proxim al in sertion , m idsubstance, or distal in sertion . Th e proxim al in sertion , at th e in ferior pole of th e patella, is th e m ost com m on location of rupture. In addition , patella ten don ruptures can be classified by th e tim in g between th e in jury an d surgery. Acute repair is perform ed within 2 weeks, an d delayed repair is perform ed after 6 weeks. Repair during the acute period is the m ost im portan t progn ostic factor. Mechanism of Injury Th e in jury occurs by th e sam e m ech an ism as in direct patella fractures an d quadriceps ruptures, an eccen tric load of th e exten sor m ech an ism . In th ese youn ger patien ts, th e quadriceps ten don h as n ot un dergon e degen eration ; an d therefore, the patella tendon is the weakest compon ent of the extensor m echanism . Presentation Patien ts present after experiencing sharp, acute pain after a stum ble or a trip. Most are unable to walk because of pain an d in competen ce of th eir exten sor m ech an ism . Relevant Anatomy Th e patella ten don run s from th e in ferior pole of th e patella to th e tibial tubercle. Th e greatest forces th rough th e patella ten don occur at 60 degrees of kn ee flexion , an d th ese forces can be as h igh as 3 to 4 tim es the body weight wh en clim bin g stairs. Physical Examination Th e patien t h as a swollen , ten der, an terior kn ee. Th e ten derness is greatest at th e in ferior pole of th e patella. A palpable defect is presen t in ferior to th e patella. Th e vast m ajority of patien ts are un able to actively exten d or perform a straigh t leg raise. Radiographic Examination AP and lateral knee radiographs reveal an in tact patella with patella alta, or a h igh -ridin g patella (Fig. 17.22). Special Tests MRI or ultrasoun d can be used in cases wh ere th e physical exam in ation is in con clusive. Differential Diagnosis Th e differen tial diagn osis in cludes quadriceps ten don rupture, patella fracture, or tibial tubercle avulsion . Treatment Non operative treatm en t is reserved for in complete tears, in wh ich active, full-kn ee exten sion is preserved. O perative treatm en t con sists of prim ary repair of th e patella ten don to th e in ferior pole of th e patella. Acute repair, with in 2 weeks, has better outcom es than delayed repair due to patella ten don scarrin g an d quadriceps con traction . Stron g

Figure 17.22 Lateral radiograph demonstrating patella alta af-

ter an acute patellar tendon rupture. (Reproduced with permission from El Attrache NS, Harner CD, Mirzayan R, Sekiya JK: Surgical Techniques in Sports Medicine. Philadelphia: Lippincott Williams & Wilkins, 2006.)

n on absorbable suture is placed in to th e patella ten don with a locked, run n in g stitch , and the tendon is then reapproxim ated to the patella through bone tunnels. For delayed repairs, th e prim ary repair m ay n eed to be augm en ted with h am strin g or fascia lata autograft or Ach illes ten don allograft. Postoperatively, th e patien t is weigh t-bearin g as tolerated in a knee im m obilizer or cylin der cast for 2 to 3 weeks. As with a quadriceps repair, m otion is th en started an d slowly advan ced over the n ext 6 to 8 weeks. Delayed repairs are m an aged m ore con servatively with delayed weight-bearing.

Complications Knee stiffness, extensor lag, extensor weakness, and patella baja are th e m ost com m on com plication s. Rerupture rates are low for acute, prim ary repair an d h igher for delayed repairs.

Patella Dislocation Patella dislocation is relatively com m on and accounts for m ost patients complaining of a knee dislocation. The dislocation is always in th e lateral direction. It is m ore com m on in wom en, owing to physiologic laxity, an d patients with hyperm obility an d con n ective tissue diseases, such as Eh lers–Dan los an d Marfan syn drom e.

Classification Patellar instability can occur in th e form of frank dislocation or subluxation. In a subluxation, there rem ains a portion of articular con tact between th e patella an d th e fem ur. Patella dislocations can be classified as acute or ch ronic.


Mechanism of Injury Patella dislocation s usually occur durin g a m aneuver in wh ich th e kn ee is sligh tly flexed an d rotated. In such a position , th e patella m ay be poorly en gaged in its groove an d vulnerable to lateral subluxation or dislocation. Predisposition to lateral dislocation of th e patella falls in to the m ain categories of hypoplasia or dysplasia, m alalignm en t, and contracture or laxity. Hypoplasia of the lateral fem oral condyle, patella alta, a shallow trochlea, dysplasia of th e patella, an d hypoplasia of th e vastus m edialis decrease the forces that keep the patella within the trochlea grove an d in crease th e risk of dislocation . An in creased Q angle, fem oral anteversion, genu valgum , external tibial rotation, and lateralization of th e tibial tubercle predispose to in stability by in creasin g th e laterally directed forces on th e patella. Laxity of th e m edial retin aculum , tigh tn ess of th e lateral retin aculum , an d gen eralized ligam en tous laxity also predispose the patient to patellar dislocations. Presentation Patients present with acute pain following an incident wh ere th e kn ee “wen t out of place.’’ Th e patien t m ay be un able to exten d th e kn ee if th e patella is un reduced. Relevant Anatomy Th e Q angle is defined as the angle form ed by a lin e from th e ASIS to the m idpatella and a line from the m idpatella to the tibial tubercle. Th e n orm al ran ge is 8 to 12 degrees, with a high Q angle being greater than 15 degrees. Patella trackin g through th e trochlear groove is balan ced by the Q angle, the lateral retinaculum , the m edial retinaculum , the m edial patellofem oral ligam en t (MPFL, th e m ajor m edial restrain t to lateral displacem en t of th e patella), an d th e VMO. Maltrackin g or lateral subluxation / dislocation can occur if any of th e followin g th ree compon en ts are presen t: th e Q an gle is too great, the lateral retinaculum is too tight, or the VMO is too weak. When the patella dislocates, the m edial retin aculum is torn an d th e MPFL is torn or stretch ed Physical Examination Wh en th e patella is dislocated, th e con tour of th e kn ee is abn orm al and displays a prom inence laterally and a void an teriorly where th e patella is usually located. Most patellar dislocations, however, are seen after either spontan eous or m an ipulated reduction , in wh ich physical exam in ation fin din gs are n on specific an d in clude swellin g, ten dern ess, an d ecchym oses. Ten derness is often present over the lateral aspect of th e kn ee, specifically over th e lateral fem oral con dyle, and m edially over the m edial facet of the patella an d th e m edial retin aculum . Radiographic Examination AP, lateral, and sun rise views of the kn ee are required. The lateral or sunrise views should be in spected for evidence of an osteochondral fragm ent.

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Special Tests Special tests are generally unnecessary. If the diagn osis is doubtful, MRI can be h elpful to visualize retin acular an d chon dral injury as well as loose bodies. Differential Diagnosis Kn ee dislocation sh ould be ruled out by physical exam in ation. Additional differential diagn oses are patellofem oral pain syn drom e, patella subluxation , MCL sprain , ACL tear, and m eniscus tear. Each of these can typically be ruled out by physical exam ination, with the patient occasion ally requirin g an MRI. Treatment Th e treatm en t of patella dislocation s sh ould be based on th e acuity of th e in jury an d th e patien ts sym ptom s. Patien ts with in itial dislocation s are treated differen tly th an patien ts with ch ron ic in stability. Initial Dislocation Th e patien t with an acute prim ary dislocation of th e patella is m anaged with prompt reduction and evaluation to rule out associated displaced osteoch on dral fractures. Osteochon dral fracture generally occurs as the patella is relocated an d th e m edial facet of th e patella impacts th e lateral fem oral condyle. Therefore, the m edial patella facet an d lateral fem oral con dyle are th e typical location s of osteoch on dral fracture. O ccasion ally, aspiration of th e h em arth rosis m ay be perform ed for com fort. If there is no osteochondral fracture, the patient’s knee should be im m obilized in either a kn ee im m obilizer or a cylin der cast for 3 to 4 weeks. Operative treatm en t is reserved for th e presen ce of displaced osteoch on dral fragm en ts or recurren t in stability. On ce im m obilization is discontinued, the patient is started on an aggressive quadriceps-strengthen ing physical th erapy program focusin g on VMO stren gth en in g. Chronic Instability Th e patien t with ch ron ic patellar in stability an d patellofem oral pain h as differen t surgical option s depending on th e exact etiology of th e in stability an d pain . Th e m ajor causes of patellofem oral pain are patella ch on drom alacia, m alalign m en t, m altrackin g, an d retin acular im balan ce. Th ese etiologies can presen t separately or togeth er, an d it is importan t that the surgical approach to the patien t address all of the etiologies to be successful. 1. Arth roscopic debridem en t an d a ch on dral procedure— Patien ts with patella ch on drom alacia can h ave partialor full-thickness dam age to the patella chondral surface. Th is ch on dral dam age can be th e source of th eir patellofem oral pain. The first step in treating these patien ts is to arthroscopically debride (chondroplasty) the un stable cartilage. A procedure to either stim ulate cartilage growth or transplant cartilage tissue to th e dam aged area can then be perform ed. The purpose of this procedure is to replace th e dam aged cartilage with a n ew

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cartilage surface to cover th e un derlyin g subch on dral bon e an d preven t pain . Microfracture is th e m ost com m only perform ed cartilage-stim ulating procedure. It involves punch ing sm all holes into the underlying subchon dral bone to cause a controlled fracture and subsequen t bleeding. This causes fibrocartilage, wh ich is essen tially “scar cartilage’’ as it h as in ferior biom ech an ical properties when compared with hyaline cartilage, to grow into the defect. The cartilage transplant procedures are th e osteoch on dral autograft tran sport system (OATS) an d autologous ch on drocyte implan tation (ACI). OATS is difficult to perform on the patella but can be utilized for troch lear lesion s. OATS in volves taking plugs of cartilage and subchondral bone from a non –weigh t-bearin g surface of th e kn ee an d tran sporting them to the dam aged area. ACI is a two-step procedure in wh ich cartilage is in itially h arvested from a n on – weigh t-bearin g area in th e kn ee. Th is cartilage is sen t to a laboratory where chon drocytes are isolated and proliferated. At a second procedure, these chondrocytes are implanted into the defect and covered with a periosteal patch . Th e exact procedure th at is ch osen depen ds on th e size and the location of the lesion. Gen erally, m icrofracture is perform ed initially, followed by either OATS or ACI. Most of th e tim es, these procedures are perform ed with a realign m en t procedure, especially in th e settin g of a large, full-th ickn ess lesion , to off-load th e dam aged area. Lateral retin acular release—A lateral release sh ould be perform ed in patien ts wh o h ave sign ifican tly positive lateral tilt. This can be detected on physical exam ination and intra-articularly during arthroscopy. It involves incisin g th e lateral retin aculum an d lettin g it retract to create a gap in the retinaculum that results in a len gthening of th e tigh t lateral structures. Proxim al realign m en t—Th is in volves tigh ten in g up th e m edial retin aculum and MPFL. This procedure is perform ed if the etiology for the instability is a weak or “stretched out’’ m edial patellar restraints. The surgery involved shortening the m edial retinaculum and MPFL, th us tigh ten in g th e m edial patellar restrain ts. Gen erally, proxim al realign m en t is perform ed in con jun ction with a lateral release to weaken the lateral restraints. MPFL recon struction —Th is procedure is perform ed in patien ts with weak or torn m edial restrain ts from patellar dislocation. Th e procedure does not realign or unload dam aged chondral surfaces of th e patella, instead it “tigh ten s’’ the m edial restraints by reconstructin g the MPFL. Th is is accomplished with eith er an autograft ham strin g tendon or an allograft soft tissue tendon . MPFLreconstructions are becom ing popular for patien ts with in stability with out sign ifican t ch on dral dam age. Distal realign m en t (Fulkerson )—Distal realign m en t procedures are perform ed at th e tibial tubercle. Th ey accom plish two m ain goals. First, th ey elevate th e tibial tubercle and, therefore, increase the m om ent arm of the

quadriceps. Th is provides a m ech an ical advan tage to th e quadriceps, con sequen tly un loadin g th e total force seen by the patella. The specific areas that are loaded during knee flexion are also altered sligh tly to unload the dam aged areas of th e patella. Secon d, th e distal realign m en t procedure m oves th e tibial tubercle m edially to decrease the Q angle. This alters the direction of the patella tendon pull to in crease th e m edial an d decrease th e lateral directed forces on th e patella. Distal realign m en t procedures h ave developed into first-line treatm ents for patien ts with sign ifican t patellofem oral arth ritis. However, for patien ts with instability, distal realignm ent procedures h ave becom e secon d-lin e treatm en ts, after MPFL recon struction .

Complications Recurrent dislocation is m ore com m on in patients with a prim ary dislocation at an age youn ger th an 20 years. Recurren t dislocation is an in dication for surgical in terven tion . Knee stiffness m ay result from prolonged im m obilization or postsurgical arth rofibrosis. Patellofem oral pain can result from ch on dral in jury at the tim e of the dislocation or from retinacular injury that results in m altracking an d subsequent chon dral dam age. Overall, 50% of patients with a prim ary patellar dislocation will improve with n on operative treatm en t; however, th e other 50% will have recurrent instability or patellofem oral pain .

Knee Dislocation Dislocation of th e kn ee is an un com m on but serious orthopaedic in jury that m ay be lim b-threaten ing and should be treated as an orth opaedic em ergen cy. Tibiofem oral (kn ee) dislocation is m uch less com m on than patellar dislocation and is a m uch m ore serious injury. Th e true in ciden ce is probably un derestim ated as 30% to 50% of dislocations spontaneously reduce before presentation.

Classification Knee dislocations are classified according to the displacem en t of the tibia relative to the fem ur (Fig. 17.23). The m ost com m on dislocation is anterior due to kn ee hyperexten sion , accoun tin g for 30% to 50% of kn ee dislocation s. Posterior dislocations are the next m ost frequent on es due to a posteriorly directed force to th e proxim al tibia, m ost com m only from the dashboard of a car. Medial, lateral, and rotation al dislocation s are less com m on an d result from a com bin ation of m echan ism s involving sagittal an d coron al and rotation al m ovem en ts. Kn ee dislocation s can also be described by th e ligam en ts th at are in volved. Most com m on ly, the ACL and PCL are involved along with at least on e of th e collateral ligam en ts. Mechanism of Injury Knee dislocations occur after substantial traum a to the knee. High-energy injuries usually occur as the result of


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Figure 17.23 Classification of knee dislocations. (Reproduced with permission from Chapman MW, Szabo RM, Marder R, et al. Chapman’s Orthopaedic Surgery. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2001.)

m otor vehicle accidents. Lower-energy m echanism s occur durin g ath letic even ts or falls.

Presentation Patients with h igh -energy traum atic m echanism s can have m ultiple traum atic injuries. Lower-en ergy injuries are m ore com m only isolated. Patients will complain of severe pain an d swelling and will be unable to bear weight. Patien ts or em ergen cy person el m ay describe an awkward position of the knee that reduced while stabilizing the lim b. Relevant Anatomy Tibiofem oral join t stability is provided predom in an tly by soft tissue restraints. For a kn ee dislocation to occur three of th e four m ain con strain in g ligam en ts m ust be torn . Most com m only, the ACL and PCL are involved along with either the MCL or LCL. Th e posterior vascular structures of the knee, including the popliteal artery and vein, the tibial nerve, and the com m on peron eal nerve, can be dam aged with a kn ee dislocation an d cause a lim b-th reaten in g in jury. Th e popliteal n eurovascular bun dle courses th rough a fibrous tun n el at th e level of th e adductor h iatus. With in th e popliteal fossa, m ultiple bran ch es arise from th e popliteal artery, including the superior m edial and lateral geniculate arteries, the m iddle geniculate artery, and the inferior m edial an d lateral gen iculate arteries. Th e popliteal artery th en run s through another fibrous tunnel deep to the soleus. Th ese bran ch es an d th e fibroosseous tun n els teth er th e popliteal artery to th e popliteal space. Th erefore, wh en a knee dislocation occurs, the popliteal artery is at great risk for kinkin g, tenting, or, rarely, tearing. Physical Examination Th e exam in ation fin din gs vary with th e type of dislocation and the tim ing of the evaluation . The knee will

be swollen an d ten der. Deform ity m ay be presen t if th e kn ee is still dislocated at th e tim e of presentation. If the kn ee is still dislocated, it should be reduced im m ediately before con tin uin g th e exam in ation . A th orough ligam en tous exam in ation sh ould be perform ed to determ in e th e exten t of th e ligam en tous in jury. Most im portan tly, a careful neurovascular exam ination should be perform ed, including ankle–brach ial in dices (ABIs). Th e n eurovascular exam in ation m ust be repeated serially over th e n ext 24 to 48 hours as vasospasm or th rom bosis from an intim al tear of th e popliteal artery can cause delayed lim b isch em ia. Vascular injury with either initial dam age or rupture occurs in 20% to 60% of knee dislocations. Collateral circulation is usually in adequate to perfuse th e distal extrem ity. Capillary refill an d distal pulses m ay be in tact despite sign ifican t arterial injury. Neurologic in jury, m ost com m only to th e peron eal n erve, can occur in up to 35% of cases an d requires careful n eurologic evaluation .

Radiographic Examination AP, lateral, an d oblique radiograph s of th e kn ee before an d after reduction are perform ed. Joint space widenin g m ay indicate in complete reduction . Ligam en tous or capsular avulsion fractures can often be visualized on radiograph s. Special Tests Th e h igh in ciden ce of vascular in jury m an dates a vascular surgery con sultation an d possible arteriography in every knee dislocation. Generally, if the initial ABI is norm al, serial ABIs can be used in lieu of an arteriogram , alth ough th is decision sh ould ultim ately be m ade by th e vascular surgeon. MRI is helpful to assess the exten t of ligam entous injury an d form ulate a reconstructive approach (Fig. 17.24).

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A

B Figure 17.24 T2-weighted magnetic resonance images showing (A) PCL tear and (B) ACL avulsion

following a knee dislocation. (Reproduced with permission from Chapman MW, Szabo RM, Marder R, et al. Chapman’s Orthopaedic Surgery. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2001.)

Differential Diagnosis Th e differen tial diagn osis in cludes distal fem ur, patella, an d tibial plateau fractures. In addition , isolated ligam en tous in jury with out dislocation sh ould be in cluded.

MCL Sprain

Treatment In itially, a prompt reduction , after n eurovascular assessm en t, sh ould be perform ed, followed by a repeat n eurovascular assessm ent an d postreduction radiographs. Concern for lim b ischem ia m andates im m ediate vascular consult an d likely in terven tion . Closed reduction is gen erally successful, alth ough som e dislocation s are irreducible as a result of “button-holing’’of the bon e through the soft tissues. In dication s for im m ediate open m an agem en t in clude open in jury, in ability to ach ieve a closed reduction , associated residual soft tissue in terposition , an d vascular in jury. The definitive treatm ent is debated. The debate surroun ds th e tim in g of ligam en t repair an d recon struction . Som e orth opaedists recom m en d im m ediate repair an d reconstruction , whereas others recom m end delayed repair or, m ore often , recon struction . Th e cruciate ligam en ts gen erally require recon struction , wh ereas th e collateral ligam en ts m ay be am en able to repair wh en addressed acutely (with in 2 to 3 weeks of in jury) but require recon struction in m ore ch ron ic cases. O utcom e studies h ave been m ixed with outcom es of persisten t pain , stiffn ess, and instability following both im m ediate and delayed treatm ent.

Classification MCL sprains are graded from I to III, with severity increasing from I to III. In grade I (m ild) in juries, there is m inor injury to the ligam ent without a full-thickness tear. There is n o detectable laxity with grade I sprain s. In grade II (m oderate) sprains, th ere is m ore significant in jury to the ligam ent, with stretch in g an d partial tearin g. Th ere is m in im al laxity presen t on exam in ation . In grade III sprain s, th e MCL is completely disrupted. There is laxity on physical exam ination without a detectable endpoint.

Complications In itial complication s in clude n eurovascular in juries. Delayed complication s in clude pain an d stiffn ess.

Relevant Anatomy Th e MCL h as both superficial an d deep layers. Th e superficial MCL originates on the m edial epicondyle of th e fem ur

MCL sprain s are the m ost com m on knee ligam en t injuries. Th e MCL h as superficial an d deep layers. Th e MCL is th e prim ary restrain t to valgus stress about th e kn ee.

Mechanism of Injury MCL sprains occur when a valgus stress is applied to th e knee. Th is frequently occurs when a player is tackled or tripped from th e side during soccer or as a contact injury in football. If the injury involves m ore of a twisting m echan ism , the MCL, the ACL, and the m edial m eniscus can also be torn; this is called th e unhappy triad of the knee. MCL injuries m ay also occur in the setting of a knee dislocation. Presentation Patients with MCL sprain s generally present with acute m edial kn ee pain followin g a traum atic in jury to th e kn ee.


an d broadly inserts along the anterior m edial proxim al tibia. The deep MCL is a thicken ing within the m edial capsule of th e knee. Th e superficial MCL is th e m ore im portan t of th e two structures in providin g valgus stability to the kn ee. The MCL m ost com m only tears off its origin on the m edial epicon dyle of the fem ur.

Physical Examination Th e specific physical exam in ation elem en ts of a kn ee with an MCL tear should include palpation of the m edial knee an d valgus stress testing. Palpation of the m edial knee sh ould in clude th e entire length of th e MCL: its origin on the m edial epicondyle (the m ost com m on location of a tear), its m idsubstan ce at th e m edial join t lin e, an d its in sertion on the anterom edial proxim al tibia. Valgus stress testin g sh ould be tested at both 30 degrees of flexion an d full extension. Valgus tress testing at 30 degrees of flexion is specific for th e MCL, and at full extension, it tests the MCL, posterom edial corner, an d cruciate ligam ents. Valgus laxity at 30 degrees in a n orm al knee ranges from 0 to 10 degrees of open in g with a solid en dpoin t an d n o ten derness. Physical exam in ation fin dings differentiate between grades I to III in juries. In grade I in juries, th ere is m in im al ecchym oses, swellin g, an d ten dern ess. Valgus stress testin g in grade I sprains elicits tenderness without m edial joint space opening and a solid endpoin t. In grade II sprains, there is increased ecchym oses, swellin g, and tenderness. Valgus stress testing at 30 degrees of flexion elicits tenderness and open ing from 10 to 15 degrees with th e presen ce of an en dpoin t. Valgus stress testin g at full exten sion will be stable. In grade III in juries, th ere is com plete tearin g of the MCL with m ore severe ecchym oses, swelling, an d tendern ess. Th ere is open in g beyon d 15 degrees with out an en dpoin t with valgus stress testin g at 30 degrees of flexion an d instability can also be present at full extension depending on the severity of the injury. Radiographic Examination AP and lateral radiographs are generally negative. With ch ronic MCL tears, calcification can be seen at the origin of th e MCL at th e m edial epicon dyle, an d th is is called th e Pellegrini–Stieda sign. Special Tests MRI is rarely n ecessary with an isolated MCL sprain; however, it is used com m on ly with m ultiligam en t kn ee in juries an d/or knee dislocation s. MRI is helpful in patien ts in wh om an addition al kn ee in jury is suspected. It can con firm addition al kn ee ligam en t in juries or m en iscus in juries that m ay require surgical treatm en t. Stress radiographs can also be perform ed by placing valgus stress about the knee wh ile an AP radiograph is taken . Stress radiograph s are especially h elpful in th e pediatric population to differen tiate physeal fractures from ligam ent sprains

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Differential Diagnosis Th e m ost importan t differen tial diagn osis is th at of a distal fem oral physeal fracture in skeletally im m ature patien ts. Other differen tial or concom itant injuries in clude ACL tears, m en iscus tears, patella subluxation or dislocation , pes ten don itis, an d ch on dral in juries. Medial m en iscus tears can be differen tiated on physical exam in ation by th e presen ce of in stability with valgus stress testin g in patien ts with MCL tears. In addition , patien ts with MCL tears are generally ten der at the m edial epicondyle, wh ereas patients with m eniscus tears are tender at the m edial joint line. The differen tial diagn osis for ten dern ess at th e m edial epicon dyle is MCL tear and patellar dislocation or subluxation. In patellar dislocation, th e MPFL tears off the m edial epicondyle, resultin g in ten dern ess. Treatment Treatm ent is nonoperative and involves im m obilization for a duration that is dependent on the degree of injury and associated in juries. Grade I sprains are treated with early range of m otion as tolerated an d early return to activity with out im m obilization. Grade II sprains require a short period of im m obilization with return to activity when the pain allows with a protective hin ged knee brace at 3 to 4 weeks. Grade III in juries are im m obilized with a cast or kn ee im m obilizer at full exten sion for 2 to 4 weeks, followed by physical th erapy to return -to-n orm al stren gth , with full return to activity by 6 to 8 weeks with a hin ged knee brace. Associated injuries sh ould be treated accordin gly an d at tim es warrant repair of grade III injuries. Protective, hin ged knee braces are com m on ly used prophylactically to preven t MCL injuries in football linem an, with m ixed results. Complications Th e m ain complication is recurren t valgus in stability an d pain th at can result from early return to activity with out brace protection .

ACL Sprain ACL sprains or tears are th e second m ost com m on knee ligam ent injury. Th ey occur in an estim ated 250,000 people ann ually.

Classification ACL ligam ent injuries are graded from I to III, sim ilar to oth er ligam en t in juries. It is difficult to distin guish between grade I an d grade II in juries; h owever, th e distin ction between partial (I or II) and complete (III) is the m ost importan t for progn ostic an d th erapeutic reason s. Mechanism of Injury ACL sprains are th e result of a single traum atic even t and are not due to overuse injuries. The exact m echan ism varies according to the sport involved, but m ost injuries involve a twisting or pivoting m echanism of an extended knee

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on a plan ted foot. ACL in juries can also occur with hyperexten sion . ACL in juries com m on ly occur in con tact sports, but th ey m ost com m on ly occur as a result of a n on con tact m ech an ism . ACL in juries are com m on in soccer, football, basketball, an d skiin g.

Presentation Th e classic presen tation is th e acute on set of pain an d swelling after a traum atic event in which th e patient lan ded awkwardly or twisted th e kn ee an d h eard a “pop.’’Th e ath lete is rarely able to con tin ue activity. Relevant Anatomy Th e ACL is th e m ost an terior of th e two cruciate ligam en ts. Th e ACL arises from th e an terom edial tibia, run s in th e in tercon dylar n otch , an d in serts posterom edially on th e lateral fem oral con dyle. Th e ACL is in traarticular an d covered by a th in syn ovial m em bran e. Th e m iddle gen iculate artery supplies th e ACL an d PCL. Th e ACL provides sagittal an d rotary stability to th e kn ee. It preven ts rotation an d an terior displacem en t of th e tibia on th e fem ur. Th e ACL m ost com m on ly tears off of its fem oral in sertion . Physical Examination Acute injuries of the ACL presen t with a tender hem arthrosis of th e knee with difficulty bearing weight. The patient m ay n ot be able to fully exten d th e kn ee due to th e effusion / hem arthrosis. The am oun t of swelling and tenderness m ay preven t an accurate exam in ation of th e ACL. Ch ron ic in juries of th e ACL presen t with a ben ign kn ee with n o effusion and asymptom atic weight-bearing. The patien t m ay not be able to fully extend th e knee due to a cyclops lesion . A cyclops lesion results wh en the scarred down torn ACL rem n an t preven ts full exten sion by obstructin g th e fem oral notch The tests for ACL in juries in clude th e Lachm an test, the anterior drawer test, an d the pivot shift test. These tests are described in th e physical exam in ation section of th is ch apter. Th e Lach m an test is th e m ost sen sitive, an d th e pivot sh ift test is th e m ost specific. It is im portan t to perform a full-knee exam in ation in a patien t with a suspected ACL tear to evaluate for addition al ligam en t or m en iscus in jury. All physical exam in ation fin din gs sh ould be com pared with th e un in jured con tralateral side. Radiographic Examination Radiograph s are gen erally n orm al with an ACL tear. O ccasion ally, a sm all capsular avulsion fracture off of the lateral tibia can be presen t with an ACL tear; th is is called a Segund sign (Fig. 17.25). Rarely, the ACL can avulse off of its origin at th e tibial em in en ce, an d th e tibial em in en ce avulsion fracture fragm ent can be seen radiographically. ACL avulsion occurs m ost com m on ly in th e adolescent population . Special Tests MRI is h igh ly sen sitive an d specific for ACLtears an d m en iscus injuries. However, in a patient with obvious physical

Figure 17.25 Anteroposterior radiograph of the knee showing

a Segond fracture, which is pathognomonic of anterior cruciate ligament injury. (Reproduced with permission from Chapman MW, Szabo RM, Marder R, et al. Chapman’s Orthopaedic Surgery. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2001.)

exam in ation fin din gs for an ACL tear, MRI adds little to the diagnosis an d does not influence treatm ent. Another special test for ACL injuries is the KT-1000. The KT-1000 is a device that evaluates and quan tifies anterior laxity of the tibia on the fem ur. It is n ot com m on ly used in clinical practice but is com m on ly used in research settin gs.

Differential Diagnosis Th e differen tial diagn osis of an ACL tear in volves th e differential diagnosis for an acute knee hem arthrosis. This in cludes ACL tear, patellar dislocation, osteochondral in jury, an d a peripheral m eniscus tear. If patients presen t acutely, the pain and effusion often prevent an appropriate exam in ation of th e kn ee. In th ese patien ts, an MRI is very h elpful at differentiating between these diagnoses. Meniscus tears occur with approxim ately 50% of ACL tears. Lateral m en iscus tears occur m ost com m on ly with acute ACL tears, and m edial m eniscus tears occur m ost com m only with chronic ACL tears. Treatment Th e option s for an ACLtear in volve n on operative treatm en t with physical th erapy or operative ACL recon struction . Th e ACL has poor h ealing potential due to its in traarticular location and lim ited blood supply. The natural history of the ACL-deficient knee in volves recurrent in stability, progressive m en iscus in jury, progressive ch on dral dam age, an d eventual sports disability and arthritis. Interestingly,


current long-term outcom e studies suggest that the risk of osteoarth ritis after ACL in jury is n ot depen den t on treatm en t, suggesting that the arthritis m ay be caused by dam age sustained by the articular cartilage at the tim e of the origin al in jury. Patien ts best suited for n onoperative treatm ent are lower level recreation al athletes or athletes involved in lessdem an din g straigh t-lin e activities (cyclin g, swim m in g, run nin g, cross-country skiing, an d rollerblading) with lim ited residual laxity after appropriate physical th erapy. Age can be a relative in dication for con servative treatm en t, as older patien ts are less active. Non operative treatm en t em ph asizes physical th erapy to restore m otion an d im prove stren gth in the ham string m uscles, which act as a dynam ic anterior stabilizer of th e kn ee. Activity m odification in cludes lim itin g an d m ore aggressive sports (football, rugby, soccer, volleyball, basketball, an d sin gles ten n is). Protective bracin g is also used as an elem ent of n onoperative treatm ent. O perative treatm en t in volves surgical recon struction with eith er autograft (tissue from th e patien t) or allograft (tissue from a cadaver) that is arth roscopically implanted as a substitute for the deficient ACL. Th e m ost com m on grafts are cen tral th ird patella ten don an d h am strin g ten don autograft. Allografts are less com m on ly used. Curren t long-term outcom e studies show no differen ce between the differen t types of grafts. ACL recon struction is h igh ly effective with approxim ately 90% to 95% of patients returning to full brace-free activity followin g a postoperative reh abilitation program . Con current m eniscus injuries should be treated appropriately. Meniscus tears that can be repaired (peripheral, horizontal tears) have better outcom es when repaired at th e tim e of ACL recon struction th an wh en perform ed in isolation.

Complications Th e m ost com m on tech n ical error in ACL recon struction surgery is inappropriate tun nel placem ent that can result in recurrent laxity and lim ited flexion. The goal of ACL recon struction is an an atom ic recon struction . Som e studies have sh own that arthrofibrosis (knee stiffness) can occur m ore com m only with acute ACL reconstruction (< 2 weeks after injury).

PCL Sprain In jury to th e PCL is m uch less com m on th an th e ACL. Th e relative in frequen cy h as led to a poorer un derstan din g of th e n atural h istory of th e in jury. PCL in juries are m ost com m only associated with knee dislocations.

Classification PCL in juries are graded from I to III, sim ilar to oth er ligam en ts. Grade III injuries represent complete tears. Associated ligam ent injury to the posterolateral corner (PLC) m ay cause a greater degree of laxity th an isolated PCL in juries.

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Mechanism of Injury Th e m ech an ism varies, but th e m ost com m on m ech an ism involves a direct blow to the an terior aspect of a flexed knee with th e an kle plan tar flexed. In th is position , th e m ajority of th e posterior force is absorbed by th e PCL in stead of th e patella. Th e PCL is usually torn in its m idportion . PCL injuries can also occur with hyperexten sion. Presentation Th e patien t presen ts with a pain ful swollen kn ee. Th e degree of symptom s depen ds on th e degree of traum a an d th e associated injuries. PCL injuries can be m issed in a patient with distractin g in juries, th e m ost com m on is a posterior h ip dislocation or posterior wall acetabular fracture in a patien t presen tin g after a m otor veh icle acciden t. In th is patien t th e sam e force th at dislocated th e h ip also caused th e PCL in jury. Associated in juries with a PCL in clude ACL, MCL, LCL, PLC, and m eniscus injuries. Relevant Anatomy Th e PCL provides approxim ately 95% of th e prim ary restraint to posterior tibial translation on the fem ur. The PCL origin ates from th e cen ter of th e posterior tibia just distal to th e articular surface, travels th rough th e in tercon dylar n otch , an d in serts on th e lateral aspect of th e m edial fem oral condyle. Its fibers are stout and stronger th an th e ACL. Directly an terior an d posterior to th e fem oral insertion of the PCL lie the m eniscofem oral ligam en ts of Humph rey an d Wrisberg, respectively, wh ich serve as attachm ents of the PCL to the posterior horn of the lateral m eniscus. Physical Examination Th e prim ary test for th e PCL is th e posterior drawer test. Th e posterior drawer test is perform ed on a supin e patien t with th e kn ee flexed 90 degrees. Th e exam in er sits on th e patien t’s foot an d push es posteriorly on th e tibia to detect th e am oun t of posterior displacem en t. Before perform in g th e test, it is importan t to take n ote of th e position of th e proxim al tibia to th e distal fem ur in relation sh ip to th e un injured side to detect any degree of posterior subluxation before perform in g th e exam in ation . Th e posterior sag sign is the test to determ ine the degree of posterior subluxation at rest, if the tibia is less than 1 cm anterior to th e fem ur and also less than the unaffected side it is a positive. The quadriceps active test is perform ed in th e sam e position as th e sag sign, by asking th e patien t to con tract quadriceps, takin g n ote of th e reduction of th e sag sign wh en th e quadriceps are con tracted. Th e degree of kn ee ten dern ess, swellin g, an d ecchym oses on physical exam ination increases with increasing grade of PCL injury from grade I to III. A grade I in jury h as m ild swellin g an d ten dern ess with n o detectable posterior laxity. Grade II in juries h ave som e posterior laxity with an endpoint and m ay have a positive sag sign. Grade III injuries have increased subluxation with out an en dpoin t an d a positive sag sign .

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Radiographic Examination Radiograph s are usually n orm al in PCL in juries. Ch ron ic PCL in juries m ay exh ibit degen erative ch an ges in th e patellofem oral an d m edial com partm en ts.

LCL Sprain

Special Tests MRI is h igh ly sen sitive an d specific for PCL in juries. MRI is perform ed wh en m ultiligam en tous in jury an d/ or kn ee dislocation is suspected. Stress radiograph s can be perform ed with a posterior force applied to th e anterior tibia wh ile a lateral radiograph is taken .

Classification LCL in juries are graded from I to III, sim ilar to th ose of oth er ligam en ts. Grade III in juries represen t com plete tears. Associated ligam en t injuries to the PLC m ay cause a greater degree of laxity th an isolated LCL in juries.

Differential Diagnosis Th e differen tial diagn osis in cludes all of th e kn ee ligam en tous in juries an d kn ee dislocation . Th e PCL m ust be considered injured until proven otherwise with a kn ee dislocation . Th e m ost importan t differen tial is to determ in e an isolated PCL in jury from th at associated with in jury to the PLC. The an atom ic description of the postero-PLC has been in con sisten t an d in cludes th e LCL, popliteus, an d th e popliteofibular ligam en t. With in jury to th e PLC in addition to th e PCL th e kn ee will be in creasin gly un stable. In addition , PLC in juries h ave been m et with poorer results if they are not repaired acutely prim arily. The prim ary physical exam in ation m aneuvers for PLC injuries are the posterolateral drawer an d th e dial test. Th e posterolateral drawer test in volves applyin g a posterolaterally directed force wh ile the patient is in the sam e position as the posterior drawer test. Th e dial test is perform ed on a relaxed, pron e patien t. Th e patien t’s kn ees are flexed to 30 an d 90 degrees an d th e am oun t of extern al rotation of th e feet is determ in ed. Adifference of greater than 10 degrees from the uninjured side is a positive test. In creased extern al rotation at 30 degrees of flexion but n ot 90 degrees suggests an isolated PLC in jury, wh ereas in creases at both 30 an d 90 degrees suggest a com bin ed PLC an d PCL in jury. Treatment Treatm en t is gen erally n on operative for isolated PCL in juries. Th is in cludes h in ged bracin g an d physical th erapy to regain th e ran ge of m otion an d stren gth . Th e n atural h istory of th e PCL-deficien t kn ee is variable with som e patien ts functionin g well an d other developing progressive instability. Surgical recon struction is reserved for patien ts wh o fail nonoperative treatm ent, patients with kn ee dislocations, or patien ts with grade III in juries with excessive posterior in stability. Recon struction in volves open or arth roscopic autograft or allograft ligam en t recon struction . Lon g-term results h ave n ot approach ed th e success seen followin g ACL recon struction . Complications Complication s in clude kn ee stiffn ess an d recurren t or ch ron ic in stability. PCL deficien t kn ees are at in creased risk for patellofem oral and m edial compartm ent degeneration.

LCL in juries are very un com m on , an d wh en th ey do occur, they are usually in association with other ligam ent injuries such as kn ee dislocation s or PLC injuries.

Mechanism of Injury An acute varus stress is responsible for the injury as the LCLis th e prim ary restrain t of varus m otion about th e kn ee. With m ultiligam entous kn ee injuries, injury to the LCL can result from a twistin g m ech an ism of th e kn ee. Presentation Th e presen tation is th at of a sign ifican tly traum atized kn ee with pain , swellin g, an d an in ability to bear weigh t. Relevant Anatomy Th e LCL is a distin ct collagen ous structure travelin g from the lateral epicondyle of the fem ur to attach to th e fibular h ead. Other structures of im portan ce on th e lateral side include the arcuate ligam ent complex composed of th e thicken ing of the posterolateral capsule, the biceps tendon, the IT band, and the popliteus tendon. The peroneal nerve courses around the fibular neck an d dives into the anterior compartm ent as the deep peroneal nerve while sendin g a bran ch in to th e lateral com partm en t as th e superficial peron eal n erve. Th e n erve is vuln erable durin g in jury to th e lateral side of the knee. Tears of the LCL are variable but are typically m idsubstance or off its distal insertion on the fibular h ead. Physical Examination Pain, swelling, ecchym oses, and tenderness over th e lateral side of th e knee are com m on. Exam ination for associated n erve in jury is importan t due to th e peron eal n erve’s proxim ity of the LCL. Ligam ent integrity can be palpated with the kn ee in the figure-of-four position and tested by applying a varus stress with the kn ee in sligh t flexion. Associated injury to the PLC is suggested if there is increased external rotation or posterior tran slation of th e tibia at 30 degrees of kn ee flexion . Lateral open in g with varus stress in full exten sion suggests addition al in jury to th e ACL an d/ or PCL. Radiographic Examination AP and lateral radiographs of the knee should be perform ed to evaluate for avulsion fractures and to rule out additional fractures or injuries. Special Tests MRI can confirm the injury and exclude or include additional ligam entous, m en iscus, or chondral injuries.


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Differential Diagnosis Associated ligam entous in juries should be included in the differen tial diagn osis, especially th e PLC, ACL, PCL, an d the possibility of knee dislocation. Treatment Treatm ent of isolated LCL injuries is usually nonoperative, with im m obilization with a cast or kn ee im m obilizer for 6 weeks followed by a reh abilitation program . For patients with associated PLC in juries, early prim ary repair is recom m en ded, as outcom es with prim ary repair are better than with secondary reconstruction. In patients with varus m alalignm ent, corrective valgus osteotomy should be considered prior to LCL repair to decrease th e varus stress on the LCL and decrease th e risk of recurren t instability. Complications Complications include knee stiffn ess and recurren t or ch ronic instability.

NONTRAUMATIC INJURIES OF THE KNEE Meniscus Tears Men iscus tears are one of the m ost com m on problem s seen in th e knee and account for the m ost com m on indication for knee arthroscopy. In younger patien ts, they are generally traum atic in origin , whereas they are m ore com m only degen erative in patien ts older th an 40 or 50 years.

Classification Men iscus tears are classified by their configuration and location (Fig. 17.26). Th e m ain tear con figuration s are as follows:

Figure 17.26 Types of meniscus tears, shown with the typical lines of resection. (Reproduced with permission from Chapman MW, Szabo RM, Marder R, et al.: Chapman’s Orthopaedic Surgery, 3rd ed. Philadelphia: Lippincott Williams & Wilkins, 2001.)

Mechanism of Injury Traum a can be respon sible for m eniscus tearing, although with age, th e fibrocartilagin ous m en isci stiffen , degen erate, and tear with little traum a. Simple sheer or rotational stress can be sufficien t to cause a tear.

1. Longitudinal or h orizontal—Tears that are parallel to the circum feren ce of th e m en iscus. 2. Radial—Tears th at are perpen dicular to th e circum feren ce of th e m en iscus. 3. Cleavage—Tears th at are in th e plan e of th e m en iscus, parallel to its superior an d in ferior surfaces. 4. Com plex—Tears th at are a com bin ation of m ore th an on e specific pattern . Th e m en iscus is divided in to th irds based on its relative blood supply an d capacity to h eal (Fig. 17.27): 1. Peripheral third—The peripheral third h as the best blood supply an d capacity to h eal and is called th e red–red zone. 2. Middle third—Th e m iddle third has an interm ediate blood supply an d is called th e red–white zone. 3. Central th ird—The central third is avascular and lacks th e capacity to h eal. It is called th e white–white zone.

Figure 17.27 The blood supply of the meniscus. (Reproduced

with permission from Johnson DH and Pedowitz RA: Practical Orthopaedic Sports Medicine and Arthroscopy. Philadelphia: Lippincott Williams & Wilkins, 2006.)

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Presentation Acute or insidious on set of pain or achin g m ay herald a tear of th e m edial or lateral m en iscus. O ccasion ally, in addition to pain , th ere m ay be a h istory of h avin g h eard a pop at th e tim e of in jury, usually wh en th e patien t twisted, squatted, or cam e down on th e leg in an awkward m an n er. In older patien ts, sym ptom on set is usually related to a low-en ergy activity, such as steppin g off a curb or gettin g out of a car. Th ere m ay or m ay n ot be a h istory of swellin g associated with the pain. Occasionally, there m ay be a history of m ech an ical lockin g in wh ich th e kn ee is tem porarily stuck in a flexed position . Relevant Anatomy Th e m en isci are th e fibrocartilagin ous sem ilun ar-sh aped disks th at occupy th e m edial an d lateral com partm en ts of th e kn ee. Th ey provide con gruen cy between th e con vex fem oral con dyles an d th e flat tibial plateau. Th eir predom in an t fun ction is th at of load distribution with a secondary contribution to stability, sh ock absorption, an d cartilage nutrition. The m edial m eniscus is circum ferentially attach ed to th e capsule an d h as little m obility. In contrast, the lateral m eniscus has no capsular attachm ent posterolaterally at th e popliteal h iatus, accoun tin g for its significantly greater m obility. Th e differential in m obility contributes to the fact that symptom atic m edial m eniscus tears outn um ber lateral m en iscus tears by an average of 4 to 1. The blood supply to the m en isci com e from the inferior m edial an d lateral gen iculate arteries. As described earlier, the peripheral portion of the m eniscus is relatively vascular an d th e cen tral portion is avascular. Physical Examination Th e kn ee exam in ation in cludes an exam in ation for quadriceps atrophy, knee effusion, and restricted ran ge of m otion. Th e m ost sen sitive fin din g is join t lin e ten dern ess th at reproduces th e patien t’s pain . Th e McMurray test, in wh ich in tern al an d extern al rotation of th e kn ee from full flexion to 90 degrees of flexion causes a palpable click, is specific for a m en iscus tear. The palpable click reflects an interm itten tly en trapped an d freed m en iscus fragm en t in th e join t lin e. Radiographic Examination Stan dard views of th e kn ee (weigh t-bearin g AP, lateral, an d sun rise views) should be taken to evaluated for osteoarth ritis. Th ey are gen erally n egative in th e youn ger population . In patien ts wh o h ave un dergon e complete m en iscectomy (surgical resection of th e m en iscus), early arth ritis with Fairbanks classic radiograph ic ch an ges will often be presen t. Fairban ks ch an ges are join t space n arrowin g, osteophyte form ation , subch on dral sclerosis, an d subch on dral cysts.

Special Tests MRI is highly sen sitive (90% –95%) and specific (90% – 95%) for m en iscus tears. However, as patien ts age, th e likelihood of finding an asymptom atic m eniscus tear on MRI is relatively high . Therefore, MRI should be utilized in cases wh en th e diagn osis is un certain to m axim ize th e utility of the MRI. Differential Diagnosis Th e differen tial diagn osis in cludes articular cartilage in jury (osteoarthritis, chondral, or osteochondral fracture), syn ovial disorders, or ligam en tous in jury. Treatment Men iscus tears are often successfully treated with nonoperative treatm en t in cludin g NSAIDs, activity m odification , an d a quadriceps-strengthening physical th erapy program . A large portion of proven m en iscus tears, especially in older, m ore seden tary patien ts, will im prove with a sign ificant duration of non operative treatm ent (1 –2 m on th s). In dication s for surgical treatm en t in clude failed con servative treatm ent, a locked knee in which the m eniscus is m echan ically blocking knee extension, and m eniscus pathology diagn osed durin g ligam en t surgery. Historically, surgical treatm ent in volved openin g the knee joint (arth rotomy) and rem oving the en tire m eniscus (m eniscectomy), which predictably led to arthritis in the involved compartm en t. Currently, with th e developm ent of kn ee arth roscopy, m en iscus tears are treated with eith er m en iscus repair or partial m eniscectomy. Efforts are m ade to preserve as m uch of th e m en iscus as possible to preven t the developm ent of degenerative arth ritis. Un fortunately, despite such efforts, m any studies sh ow th at even partial m en iscectomy can lead to degenerative changes with tim e. Certain m en iscus tears can be repaired. The gold standard is an “inside-out’’m eniscus repair, during which sutures are threaded th rough the m eniscus from inside the knee and a knot is tied outside of the capsule to secure the repair. “Outside-in ’’ and “all-inside’’ m eniscal repairs can also be perform ed. Repairable m en iscus tears are lon gitudin al in con figuration and in th e peripheral aspect of the m eniscus. The periph eral tears exist in th e vascular portion of th e m en iscus an d are therefore capable of healing. Only approxim ately 5% of m en iscus tears are repairable. Men iscus tears th at are repaired at th e sam e tim e as ACL recon struction have the highest success rate of healing. Greater success h as been attributed to return in g stability to th e kn ee and the fact th at a hem arth rosis occurs secondary to the ACLrecon struction in the knee. Lateral m eniscus tears occur m ore com m only with acute ACL tears, whereas m edial m eniscus tears occur m ore com m on ly in ch ron ically ACL deficien t knees. Th e fin al surgical treatm en t for m en iscus tears in patients who rem ain symptom atic after m eniscal rem oval with out arth ritic in volvem en t is m en iscus replacem en t.


Allograft (from cadaver tissue) m eniscus replacem ent is indicated in a sm all percentage of patien ts with m eniscaldeficien t kn ees. Th ese are patien ts wh o are m en iscus deficient without arthritis, have norm al alignm ent, and have a stable kn ee. Surgical correction of knee m alalignm ent with a high tibial osteotomy or surgical corrected knee instability with an ACL reconstruction m ay need to be perform ed prior to or with a m en iscus allograft. Moderate lon g-term success can be expected with m eniscus allograft replacem en t. Currently, research is ongoing regarding syn th etic total an d partial m en iscus replacem en t.

Complications Th e m ain complication of m en iscus tears is degen erative arthritis as previously described.

Patellofemoral Pain Syndrome Patellofem oral pain syndrom e is one of th e m ost com m on causes of knee pain . Historically term ed chondromalacia (literally, softening of the articular cartilage), the pain is usually due to patellar m alalign m en t rath er th an ch on dral breakdown .

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ch an ical kn ee problem s, activity such as walkin g usually m akes th e symptom s better rath er th an worse.

Relevant Anatomy Th e patella fun ction s to effectively len gth en th e lever arm of th e quadriceps m uscle. In full exten sion , stan din g or supin e, th e patella lies superior to the troch lear groove. As th e kn ee is flexed, th e patella begin s articulatin g with th e trochlear groove, with progressively increasing contact with knee flexion. Physical Examination First, the patien t’s overall alignm ent is evaluated. Passive m alalignm en t is evaluated by notin g th e Q angle. The Q an gle is th e an gle form ed from a lin e drawn from th e ASIS to th e patella an d a lin e drawn from th e patella to th e tibial tubercle (Fig. 17.28). The norm al Q angle is approxim ately 10 degrees an d is slightly greater in wom en. The Q angle should n ot exceed 15 degrees. As the patient stands

Classification Th ere is n o specific classification system for patellofem oral pain syn drom e. Patellofem oral pain syn drom e is a broad classification that includes m ultiple etiologies includin g traum a, overuse, instability, and idiopathic causes. Mechanism of Injury Most patients with patellofem oral symptom s have underlying patellar m alalignm ent. Abn orm al patella tracking leads to abn orm al pressure on th e articular cartilage. Alth ough the articular cartilage is without sensory nerve en dings, the un derlyin g subch on dral bon e is n ot, an d th e abn orm al forces from asym m etrical loadin g are perceived as pain. Rarely is th ere actual structural in jury to th e patella articular surface, whose thickness of 8 to 10 m m is th e th ickest hyaline cartilage in th e body. When such soften ing does occur, it is known as chondromalacia. Th e term s chondromalacia and patellofemoral pain syndrome are not synonym s. Chondrom alacia specifically refers to the condition in which there is path ologic soften in g of th e cartilage surface. Presentation Patients present with vague pain in the front of th e knee, often bilaterally, an d usually with n o h istory of specific injury. Pain is exacerbated by activities in which the knee is flexed, such as rising from a chair, stair clim bing, and squatting. Descendin g stairs m ay be the m ost painful activity because the stress felt at the patellofem oral joint with descen din g stairs is 6 tim es th e body weigh t, versus 3 tim es the body weight with ascending stairs. Un like other m e-

Figure 17.28 The Q angle is a helpful measure of patella track-

ing. There are differing opinions as to whether the Q angle is best measured in extension, 30 degrees, or 90 degrees of flexion. (Reproduced with permission from Johnson DH, Pedowitz RA. Practical Orthopaedic Sports Medicine and Arthroscopy. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

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an d walks, careful atten tion is paid to th e position of th e foot to identify any pronation that will increase the Q angle. With th e patien t seated, observe th e position of patellae. In patien ts with excessive lateral tilt, th e patellae appear as “grassh opper eyes’’ tilting laterally away from each oth er. In spect for active m alalign m en t by h avin g th e patien t actively exten d th e kn ee wh ile seated. Th e “J’’sign occurs wh en the patella reduces m edially into the trochlear groove as the knee m oves from full extension to flexion . The quadriceps is inspected for overall developm ent, specifically the VMO. Quadriceps atrophy or hypoplasia contributes to m altracking. With th e patient supine, the physician sh ould evaluate th e m obility of th e patella. In ability to elevate th e lateral aspect of th e patella to a n eutral position in dicates tigh tn ess of th e lateral retin aculum , which is also known as a positive “patellar tilt’’sign. Ability to laterally displace th e patella m ore th an 50% of its width suggests lax m edial retin acular restrain ts, a fin din g in both m alalign m en t an d in stability. If th e patien t displays appreh en sion wh en attem ptin g lateral patellar displacem en t, there m ay be actual instability contributing to or respon sible for th e patien t’s sym ptom s. In the seated position, the exam iner palpates over th e patellofem oral join t wh ile th e patien t actively exten ds th e knee, notin g any crepitus. The opposite knee m ust be palpated as well, sin ce crepitus m ay be a n orm al fin din g. Crepitus m ay reflect articular path ology or m ay be due to in term itten tly en trapped an d bowstrin ged syn ovial ban ds within the patellofem oral joint. Palpation of the m edial an d lateral patellar facets is often ten der.

Radiographic Examination Radiograph s sh ould in clude AP an d lateral views of th e knee an d a view tangen tial to the patellofem oral joint. A tangential view (sunrise, Merch ant, Laurin) helps evaluate patellofem oral con gruen cy, trackin g, an d arth ritis (Fig. 17.29). Special Tests Th ere are n o special tests n ecessary to con firm th e diagnosis of patellofem oral pain syndrom e. Som e clinician s have found tangential radiographs at different an gles of knee flexion helpful to better evaluate the relation ship of the patella to the trochlear groove. However, such tests are static and do not take in to account dyn am ic forces of m uscle pull during activity. This lim its th e usefuln ess not only of radiograph s but also of CT an d MRI. Differential Diagnosis In ch ildren , an terior kn ee pain is presum ed h ip path ology un til proven oth erwise. Wh en ten dern ess is localized to th e tibial tubercle, th e con dition m ay be Osgood –Sch latter syn drom e, a con sequen ce of repetitive traction stresses to th e vuln erable tibial tubercle apophysis. Local ten dern ess an d radiographic changes with fragm en tation and en largem ent of th e tibial tubercle apophysis con firm th e diagn osis. In

Figure 17.29 Merchant view of the patella, showing severe lat-

eral patella tilt. (Reproduced with permission from Johnson DH, Pedowitz RA. Practical Orthopaedic Sports Medicine and Arthroscopy. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

older adolescen ts an d adults, an terior kn ee pain m ay occur m ore over the patellar tendon rath er than th e patella itself an d is known as patellar tendonitis ( jumper’s knee). Another cause of anterior knee pain is bipartite patella, in which a separate ossification cen ter persists, m ost com m only at the superolateral aspect of th e patella. This is usually incidental an d rarely accounts for patient symptom s. However, if tendern ess is presen t directly over th e fragm en t, th e fragm en t m ay need to be excised to improve symptom s.

Treatment It is importan t to rem em ber th at m ost patien ts with patellofem oral pain syn drom e h ave n o actual articular cartilage dam age. The m ainstay of treatm ent is to identify an d correct m alalignm ent or m altracking. Physical therapy em ph asizes quadriceps-stren gth en in g, specifically th e VMO , through short-arc quadriceps exercises. Som e patients benefit from McCon n ell tapin g of th e patella in to a corrected tracking position . Surgical treatm en t is reserved for patien ts wh o are un respon sive to con servative treatm en t, h ave a suspected articular cartilage lesion, or have significant m alalignm en t. Surgical treatm en t in volves appropriate treatm en t of th e articular cartilage lesion an d treatm en t of the m alalignm ent as detailed in the patella instability section of this ch apter. An arthroscopy is perform ed to evaluate the articular surface. If an articular lesion is presen t, th e patien t is treated with ch on droplasty, m icrofracture, or possibly ACI. Th en the m alalignm en t is addressed. If the patient has a positive patella tilt test an d arth roscopically th e patella is tilted in the trochlear groove, a lateral release of the lateral retinaculum can be perform ed. Th e lateral release weaken s th e lateral constraints of the patella to decrease the am ount of lateral m altrackin g. If th e patien t h as a large Q an gle, a distal realign m en t procedure can be perform ed. Th e m ost


com m only perform ed distal realignm ent procedure is th e Fulkerson procedure. Durin g th is procedure, th e tibial tubercle is cut an d sh ifted an teriorly an d m edially. Th e m edial sh ift decreases the Q angle. Th e an terior sh ift off-loads th e dam aged articular cartilage of th e patella an d in creases th e m om ent arm of the quadriceps m uscle.

Complications Complications include recurrent pain, patellar instability, nonunion, and patellofem oral arth ritis.

IT Band Syndrome IT ban d syn drom e is an overuse in jury of th e lateral kn ee. It is also called cyclist’s or runner’s knee.

Presentation Th e patien t will presen t with pain alon g th e lateral kn ee that usually relates to run ning or cycling. Symptom s are often preceded by a ch an ge in train in g regim en , such as an increase in m ileage, intensity, terrain surface, or chan ged sh oe wear. Mechanism of Injury IT ban d syn drom e is a friction syn drom e over th e lateral part of th e leg. Repetitive m otion of th e ten se IT ban d over the lateral epicondyle is though t to cause a bursitis between the tendon and th e lateral epicondyle. Relevant Anatomy Th e ITban d origin ates on th e gluteus m axim us as th e ten sor fascia lata an d in serts at Gerdy tubercle on th e an terolateral aspect of the tibia. As it travels to th e knee, it runs over the greater troch an ter of th e h ip an d th e lateral epicon dyle of the fem ur. A friction syndrom e involving th e IT band can develop at th e greater troch an ter as troch an teric bursitis, the fem oral epicondyle, or Gerdy tubercle. Fem ale patients have a wider pelvis and greater valgus alignm ent of th eir knees, wh ich predispose them to IT band syndrom e. Physical Examination Th e patien t will h ave focal ten dern ess over th e lateral epicon dyle. Occasionally, th e Ober test will be positive. The Ober test is perform ed by lying the patien t laterally on the un involved side. Then the h ip is adducted and the knee is flexed 90 degrees; the hip is then gently extended, abducted, an d th e kn ee is exten ded. Tigh tn ess an d irritation over th e IT ban d will result in pain , wh ich is a positive Ober test.

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Differential Diagnosis Th e differen tial diagn osis for lateral kn ee pain in cludes lateral m en iscus tear, LCL sprain , lateral com partm en t arth ritis, proxim al tibiofibular joint pathology, peroneal n erve path ology, or IT ban d syn drom e. Treatment Treatm ent is nonoperative for th e vast m ajority of patients and in cludes activity m odification, NSAIDs, and physical th erapy to in clude a th orough stretch in g program of th e IT ban d, h am strin gs, an d glutei. A compression strap worn above th e lateral epicon dyle during activity m ay improve sym ptom s. Most patien ts are able to return to their previous level of activity. Rarely, corticosteroid injection s or surgical release are n eeded.

Osteochondritis Dissecans Alth ough ch on dral or osteoch on dral in juries can be caused by acute traum a, a m ore com m on cause is O CD. In this con dition , a portion of th e n orm al articular cartilage is dissected away from its un derlyin g subch on dral bed. Th e m ost com m on location in the kn ee is the lateral aspect of th e m edial fem oral con dyle, in m ore th an 80% of cases.

Classification Osteoch ondral injuries have been classified on the basis of th e fragm en t’s relation sh ip to th e bon e from wh ich it arises. Agrade I lesion is in com plete with out actual complete fracture line extending from the underlyin g subchondral bone into the joint. In a grade II lesion , there is a complete fracture line exten ding from the subch ondral bone to the joint, but th e fragm en t is still with in th e bed an d m in im ally displaced. In a grade III lesion , th e fragm en t is loose with a fracture plane around the lesion, which loosely lies in its bed. In a grade IV lesion , th e fragm en t h as becom e detach ed an d is free with in th e join t. Mechanism of Injury Th is con dition h as been attributed to a vascular in sult of th e growin g epiphysis of skeletally im m ature patien ts. Th e con dition is m ost frequen tly seen in th e lateral aspect of th e m edial fem oral con dyle of th e knee; however, it has been described in th e elbow on th e capitellum an d th e an kle on th e talus.

Radiographic Examination Stan dard radiograph ic views of th e kn ee are n egative.

Presentation Th e m ost com m on presen tation is th at of an adolescen t or youn g adult with kn ee join t sym ptom s of in term itten t pain , swellin g, or catch in g related to kn ee activities.

Special Tests Rarely, an MRI is obtain ed an d can sh ow in creased sign al at Gerdy tubercle or the lateral epicondyle.

Physical Examination Physical fin din gs are usually n on specific, an d th e diagn osis is afforded by im aging studies.

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Baker cyst Described by Baker in the late 1800s, this condition is a well-known accompan im en t of several knee disorders. Rath er th an a discrete en tity, it is actually a n orm al an atom ic structure that becom es prom inent in response to knee path ology.

Presentation Most Baker cysts com e to the physician’s attention when discovered by MRI. Occasion ally, th e patien t will n ote a prom in en ce in th e popliteal area. Less com m on ly, patien ts m ay presen t with acute pain and swelling in their proxim al calf as a consequence of cyst rupture, with spillin g of the synovial contents in to the posterior compartm ents of the leg.

Figure 17.30 T2 weighted MRI of the knee demonstrating high

signal behind osteochondral fragment, indicating an unstable fragment. (Reproduced with permission from El Attrache NS, Harner CD, Mirzayan R, Sekiya JK: Surgical Techniques in Sports Medicine. Philadelphia: Lippincott Williams & Wilkins, 2006.)

Radiographic Examination Stan dard radiograph s of th e kn ee sh ow a localized area of radiolucen cy (decreased density) in the area of th e OCD. O ften , th e osteoch on dral fragm en t is sclerotic (in creasin gly den se) an d m ay be partially or com pletely detach ed from its un derlyin g bed. Special Tests MRI is useful to localize th e lesion an d determ in e its size an d stability. Un stable lesion s h ave fluid beh in d th e lesion that can be seen on T2-weighted MRI im ages (Fig. 17.30). Treatment Treatm en t varies accordin g to th e lesion ’s size, location , stage, an d the patient’s age. In skeletally im m ature patien ts, n on displaced osteoch on dral fragm en ts are th ough t to h ave h ealin g poten tial with im m obilization . Con versely, in older adolescen ts or youn g adults, particularly wh en there is evidence of fragm ent displacem ent, definitive treatm en t in volves debridem en t an d, if possible, fixation of the fragm ent with h eadless screws. A num ber of strategies have been devised for treating the defect left behind followin g debridem en t of an OCD. Th ese in clude m icrofracture, OATS, an d ACI, as discussed previously in th e patellar in stability section of this ch apter. Complications Th e m ajor complication is th e developm en t of degen erative arth ritis in th e in volved compartm en t.

Relevant Anatomy Th is structure is a n orm al bursa of th e sem im em bran osus an d is present in an estim ated 35% to 50% of patients. Syn ovial fluid gen erated with in th e kn ee in respon se to m en iscal, ch ondral, or synovial path ology can lead to bursa disten tion due to direct com m un ication with th e join t. Physical Examination Baker cysts are alm ost always located posterom edially in the kn ee. Usually, there is an indistinct area of tenderness in the popliteal fossa. Radiographic Examination Radiograph s are usually n egative, alth ough occasion ally osteoch on dral fragm en ts can be seen posterom edially. Special Tests Special test are un n ecessary in patien ts with a typical h istory. Im agin g by MRI dem on strates th e cyst an d oth er in traarticular pathology and is the diagnostic test of choice. Aspiration of the m ass yields golden-yellow viscous synovial fluid. Its viscosity m an dates th e use of a large-bore n eedle, such as an 18-gauge, to en sure successful aspiration. Differential Diagnosis Th e presen ce of a n eoplasm m ust be con sidered in th e patient presenting with fullness or a palpable m ass in the popliteal fossa. Im agin g is alm ost always con ducted to rule out th is possibility. In th e patien t with acute pain an d swellin g of the proxim al calf, consideration m ust be given to a deep vein th rom bosis. Men iscal cysts are differen tiated in th eir size and location. They are very discrete grape-like structures th at occur directly along the joint line and are m ost com m only associated with m eniscus tears. Treatment Baker cysts are often diagn osed as an in ciden tal finding on MRI perform ed for kn ee symptom s. Most cysts will


resolve on defin itive treatm en t of th e in traarticular path ology, such as partial m en iscectom y. Occasion ally, th e cyst itself produces symptom s due to its size. Aspiration, followed by corticosteroid injection, is an alternative but, if un successful, surgical excision is often curative

TRAUMATIC INJURIES OF THE LEG Midshaft Tibia and Fibula Fractures Fractures of th e tibia an d fibula sh afts are th e m ost com m on long bone fractures. Men are m ore affected than wom en , with th e average age bein g 37 years.

Classification Fractures are described by fracture pattern type: tran sverse, spiral, oblique, an d com m inuted; th e location: proxim al, m iddle, and distal; and the type an d degree of displacem en t. The presence of associated soft tissue injuries are also ch aracterized according to the Gustilo and An derson classification of open fractures. Grade I fractures are clean, with a wound less th an 1 cm . Grade II fractures have m ore extensive soft tissue dam age and a wound generally greater th an 1 cm and less than 10 cm . Grade IIIA fractures are complex fracture patterns or crush in juries with extensive soft tissue dam age. Grade IIIB are exten sive in juries with periosteal stripping requiring soft tissue flap coverage. Grade IIIC are fractures with associated vascular injuries requiring repair. Mechanism of Injury Th ere are th ree com m on m ech an ism s of in jury. Direct traum a can be from high-en ergy injury, such as a m otor veh icle accident, or a low-energy direct blow, such as during a sportin g event. In direct traum a can occur when the foot is fixed and the leg is torqued, as can occur in sporting events or a fall from a short height. Finally, fractures can occur as a result of penetrating injury such as gunsh ot woun ds. Presentation Patients present with acute leg pain accompanied with deform ity and swelling followin g a traum atic in jury. Relevant Anatomy Th e tibia an d fibula are lon g bon es, with th e tibia dem on stratin g a triangular sh ape when viewed in axial cross section. Its an terior border is rather sharp, subcutaneous, and quite vuln erable to traum a. Th e fibula is join ed proxim ally to the posterolateral proxim al tibia at the proxim al tibiofibular join t. Distally, the fibula articulates with the distal tibia laterally at the ankle m ortise. Four distinct compartm ents contain the soft tissue an d neurovascular components of the leg and include the anterior, lateral, superficial posterior, and deep posterior com partm ents (Fig. 17.11). The blood supply is alm ost entirely from th e

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popliteal artery, wh ich in th e proxim al th ird of th e leg sen ds bran ch es an teriorly th rough th e in terosseous m em bran e to provide blood supply to th e an terior an d lateral com partm en ts. Th e origin of th is vasculature, at th e trifurcation in the proxim al leg, is a site of vulnerability with potential vascular com prom ise, isch em ia, an d lim b loss followin g traum a to th is area. Nerve supply is via th e com m on peron eal n erve an d th e posterior tibial n erve.

Physical Examination Physical exam in ation sh ould focus on close in spection to rule out open fracture. In addition, a thorough secon dary survey sh ould be perform ed to rule out associated injury. Compartm ent syndrom e is a consideration with all tibia fractures with pain severe with passive dorsiflexion or th e foot or toes one of the earliest physical findings. Radiographic Examination Radiograph s sh ould in clude AP an d lateral views of th e full length of th e tibia and fibula; AP and lateral views of the knee; and AP, lateral, and m ortise views of the ankle. Special Tests Further radiographs are obtained depending on the clinical suspicion of associated injuries. If the fracture line extends into the knee or ankle join ts, CTscans of these join ts should be con sidered. Doppler evaluation an d an kle–brach ial in dices sh ould be used to evaluate vascular status in th e setting of a possible injury. An arteriogram is the definitive test for suspected vascular in jury. Differential Diagnosis Th ere is little in th e differen tial diagn osis; h owever, correct and prompt diagn osis of associated neurovascular injury includin g compartm ent syndrom e should be m ade. A high index of suspicion for the developm ent of compartm ent syn drom e sh ould be m aintained before and after defin itive treatm ent of these fractures. Compartm ent syndrom e is a clinical diagnosis based on ten dern ess with passive stretch of th e in volved compartm ent, pain out of proportion to exam in ation, and a tense com partm en t. If th e diagn osis is question ed, th e com partm ent pressure can be directly m easured. This is obtain ed with a h an d-h eld m on om eter or arterial lin e th at is placed directly in to th e compartm en t. Com partm en t syn drom e is a cyclic process started wh en th e compartm en t pressure exceeds th e ven ous outflow pressure of th e com partm en t. Th is results in ven ous stasis, resultan t in creased pressure and eventual isch em ia. Interven tion needs to occur before the process starts so the cutoff of the compartm ent pressure above wh ich a fasciotom y sh ould be preform ed is 30 m m Hg or with in 30 m m Hg of ven ous pressure. Th e treatm ent for compartm ent syndrom e is fasciotomy.

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Treatment Treatm en t depen ds on th e type of fracture. For closed fractures, nonoperative treatm ent is often acceptable, with closed reduction an d long leg cast application. General guidelin es for acceptable reduction in clude less th an 5 degrees of varus an d valgus an gulation , less th an 10 degrees of rotation al deform ity, less th an 1 cm of sh orten in g, less than 5 m m of distraction, and m ore than 50% cortical contact. Wh en treated n on operatively, a lon g leg cast is placed with initial n on –weigh t-bearin g tran sition in g to progressive weigh t-bearing as the fracture begin s to heal. Healin g averages 16 weeks and th e risk of displacem en t warrants frequent follow-up evaluation to ensure m aintenance of reduction . Closed treatm en t is m ost effective for low-en ergy fractures with little displacem ent, with healing rates as high as 97%. Un stable fractures, th ose in wh ich reduction cann ot be ach ieved or m ain tain ed, are usually can didates for IM n ail fixation . Plates an d screws can be utilized for proxim al or distal fractures an d in traarticular fractures. Th e IM n ail h as becom e th e stan dard of care for extraarticular m idsh aft tibia fractures. Th e IM n ail allows for im m ediate weigh tbearin g, low n on un ion rates, an d low in fection rates. O pen fractures m ust be treated with atten tion to woun d m an agem en t an d fracture stability. An tibiotics sh ould be in stituted im m ediately in th e em ergen cy departm en t alon g with tetanus prophylaxis. Open wounds sh ould be sterilely covered, splinted, and treated as a surgical em ergency with prom pt surgical irrigation an d debridem en t an d fracture fixation . Repeat debridem en t an d flap coverage or vascular repair m ay be required. Th e option s for fracture fixation in clude IM n ails or external fixation devices. For grade I and som e grade II fractures, an IM nail can often be placed at th e tim e of th e in itial debridem en t. For h igh er grade in juries, an extern al fixator is applied un til th e woun d is stable an d then the external fixation device is often rem oved and an IM n ail is placed for defin itive fracture treatm en t. Con version from an extern al fixator to a nail is perform ed only within the first 3 weeks to decrease the risk of spreading osteomyelitis to th e tibial can al from in fection aroun d th e extern al fixator pin s. Complications Complication s are n um erous, th e m ost com m on complication s are soft tissue related, in cludin g in fection . Oth er com plication s in clude delayed un ion , n on un ion , m alun ion , knee or ankle stiffness, throm boem bolic disease, compartm en t syn drom e, an d lim b loss.

NONTRAUMATIC INJURIES OF THE LEG Tibial Stress Fractures Tibial stress fractures are m ost often en coun tered in ath letes an d m ilitary recruits. Th e m ajority of stress fractures occur

in the lower extrem ity, with 50% of cases in the tibia or fibula. Stress factures are seen m ost com m only in wom en and are can be related to m alnutrition.

Mechanism of Injury A stress fracture occurs wh en repetitive loads exceedin g the rem odelin g capability of th e in volved bon e are applied. Cyclic loading above the level of norm al bone rem odeling causes osteoclastic to exceed osteoblastic activity. This results in weaken in g of th e bon e an d fracture. Presentation Tibial stress fractures are con sidered overuse in juries. Th ey are m ost com m only seen with rapid increases in frequency, duration , or in ten sity of ath letic activity. Pain is th e m ost com m on symptom associated with tibia stress fractures. It is generally located in the anterior leg at the m idaspect of the tibia. Pain is worse with activity such as jumping. Relevant Anatomy Th e tibia h as a n orm al bow th at h as its aspect alon g th e an terior m idsh aft. Th e m ost com m on location for tibia sh aft fractures is the anterior m idshaft of the tibia. As a result of th e an terior tibia bow th e an terior aspect of th e tibia is un der ten sile load an d th e posterior aspect of th e tibia is un der com pressive load. Physical Examination Physical exam in ation reveals a poin t ten der area alon g th e an terior m idsh aft of the tibia. Th ere m ay be an irregular thickening palpable at the tender aspect of the anterior tibia. In addition , axial compression to th e tibia exacerbates th e pain . Radiographic Examination AP and lateral radiograph s of the tibia m ay reveal signs of a stress fracture. Cortical hypertrophy m ay be present at th e stress fracture. In addition a “dreaded black line’’can occur in the cortex. This is an infraction line th at is con sidered the sign of an impen ding fracture (Fig. 17.31). Special Tests Radiograph s can be n egative for as lon g as 3 weeks after the onset of symptom s. If radiographs are n egative, MRI or bon e scan can be perform ed. In creased T2 in ten sity on MRI or increased uptake on bone scan are the signs of stress fracture. Differential Diagnosis Th e differen tial diagn osis is m edial tibial stress syn drom e an d exertional compartm ent syndrom e. This can generally be distin guish ed from tibial stress fracture by h istory an d physical exam in ation .


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Figure 17.31 Stress fracture of

the anterior middiaphysis of the tibia. Notice the extensive cortical hypertrophy in addition to the transverse infraction (A) and the multiple horizontal translucencies (B). C: Immediately after IM nailing. D: Healed fractures with extensive anterior cortical thickening. (Reproduced with permission from Chapman MW, Szabo RM, Marder R, et al.: Chapman’s Orthopaedic Surgery, 3rd ed. Philadelphia: Lippincott Williams & Wilkins, 2001.)

A,B

Treatment Most tibial stress fractures improve with activity m odification by avoiding impact loading activities for 4 to 8 weeks. Th is is ach ieved with crutch es an d with or with out casting. Tibial stress fractures can result in nonunion because of th eir location on th e ten sile aspect of th e tibia, wh ich results in fracture distraction and the relative hypovascularity of th e tibia. A difficult tibial stress fracture can be treated with an extern al bon e stim ulator an d a patella ten don bearing cast. If the patient continues to be symptom atic after 4 to 6 m on th s of n on operative treatm en t, th en surgical treatm en t with an IM rod is indicated. Complications Complications of tibial stress fractures include non union an d overt fracture of the m idshaft of the tibia.

Medial Tibial Stress Syndrome (Shin Splints)

C,D

m en t th at it is an overuse in jury. Periostitis of th e soft tissue m uscular attach m en ts alon g th e posterom edial tibia is thought to be the m ost likely cause of this syndrom e.

Presentation Th e presen tation is in dicative of its n am e. Pain over th e sh in and posterom edial tibia occurs, usually as a consequence of run n ing, often on h ard, flat terrain. Discom fort is usually durin g activity, but with con tin ued run n in g, it can lead to pain even with walkin g. Relevant Anatomy Medial tibial stress syndrom e occurs over the posterior m id to distal th ird of the tibia. Physical Examination Diffuse ten dern ess to palpation is usually presen t over th e posterom edial m id to distal th ird of th e tibia.

One of the m ost com m on problem s seen am ong runners is “shin splints,’’also known as medial tibial stress syndrome.

Radiographic Examination Radiograph s are n egative.

Mechanism of Injury Th e path ophysiology of th is con dition is n ot well un derstood. Historically, this con dition was th ough t to be a consequen ce of one of several entities, in cluding periostitis, posterior tibial ten don itis, soleus ten don itis, or early stress reaction in th e bon e. Th ere is n o absolute con sen sus on the etiology of this condition, although there is wide agree-

Special Tests An um ber of special tests have been described, in cluding injection in to adjacen t soft tissue with local an esth etic. However, relief does n ot com pletely con firm th e diagn osis or defin itively exclude th e possibility of a stress fracture. Bon e scan s dem onstrate diffuse uptake of the tracer along the distal th ird of th e tibia.

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Differential Diagnosis Th e m ain differen tial to con sider is th at of a tibial stress fracture, which is well dem onstrated on the bone scan as a focal hot spot in comparison with the m ore diffuse dye take-up in tibial stress syn drom e. Treatment Defin itive treatm en t is rest. Usually, activity m odification results in n ear-im m ediate improvem en t. Wh en ath letes can return to th eir run n in g depen ds upon th e severity, in ten sity, duration , and goals of individual patients. Ice m assage several tim es a day over the painful area com bin ed with the use of NSAIDs can improve symptom s. Som e studies have suggested that the use of arch supports m ay help th ose with m arked pronation. Heel cord stretch ing m ay also be useful in som e patien ts. Cross-train in g to m ain tain con dition in g th rough swim m in g, cyclin g, an d even run n in g with a weighted vest in a pool are en couraged until th e condition resolves. Importan tly, preven tion of th is con dition is possible th rough correctin g any iden tified train in g errors such as excessive m ileage, h ard surfaces, an d in adequate sh oe wear.

Exertional Compartment Syndrome Compartm en t syn drom e, in wh ich th e elevated compartm en t pressure can lead to m uscle isch em ia, pain , an d poten tial n ecrosis, m ost com m on ly occurs in th e traum atized extrem ity. However, th is con dition can also occur in th e absen ce of discrete traum a an d is seen am on g ath letes as exertion al com partm en t syn drom e. Th is m ost com m on ly affects th e an terior an d deep posterior compartm en ts of the leg.

Mechanism of Injury Exertion al compartm ent syndrom e occurs as a consequen ce of progressive in creased compartm en tal pressure due to activity, m ost com m on ly occurrin g in th e leg wh ile run ning. Progressive m uscle hypertrophy and swellin g durin g activity comprom ises th e n orm al blood supply, leadin g to poten tial isch em ia an d pain . Presentation Unlike stress reactions or shin splints, where pain is bearable an d th e patien t can con tin ue run n in g with th e pain , pain with exertion al com partm en t syn drom e is severe en ough to force th e ath lete to stop run n in g. Un like stress reaction s or fractures, th e symptom s promptly van ish after cessation of activity. Physical Examination Physical exam in ation is un rem arkable. Th ere is n o particular focal ten dern ess or n eurologic abn orm ality.

Radiographic Examination Radiograph s are n egative. Special Tests Th e diagn osis of exertion al compartm en t syn drom e is establish ed by com partm en t pressure m easurem en ts at rest an d followin g activity. Usin g a sm all n eedle attach ed to a pressure m an om eter setup, each of th e four com partm en ts are m easured in both th e legs an d recorded. Th e ath lete run s on a treadm ill un til symptom atic an d then compartm ent pressures are m easured again and com pared to preexercise levels. Th e exact criteria n ecessary for diagn osin g compartm en t syn drom e are som ewh at variable, but in general, pressure m easurem en ts in excess of 15 m m Hg at rest or m ore th an 20 m m Hg 5 to 15 m inutes postexercise are suggestive of exertion al com partm en t syn drom e. Differential Diagnosis In th e patien t with equivocal in tracompartm en tal pressure readin gs an d th e presen ce of bon e ten dern ess, m edial tibial stress syn drom e is a m ore likely diagnosis. Treatment Ath letes can either m odify th eir activity (i.e., give up run n in g) or h ave the affected compartm ent(s) surgically decom pressed. Th is surgical procedure in volves a sm all incision over th e affected compartm ent, followed by an incision of the surrounding fascial envelope. Th e outcom e is predictably good. Complications Th e m ajor risks with compartm en t release are superficial peron eal n erve in jury an d in adequate release.

RECOMMENDED READINGS Albert MJ. Supracondylar fractures of the fem ur. JAm Acad Orthop Surg. 1997;5:163 –171. Berkson EM, Virkus WW. High -energy tibial plateau fractures. J Am Acad Orthop Surg. 2006;14:20 –31. Brown e JE, Bran ch TP. Surgical alternatives for treatm en t of articular cartilage lesion s. J Am Acad Orthop Surg. 2000;8:180 –189. Greis PE, Bardana DD, Holm strom MC, et al. Meniscus injury, I: basic science and evaluation . J Am Acad Orthop Surg. 2002;10:168 – 176. Greis PE, Holm strom MC, Bardana DD, et al. Men iscus injury, II: m anagem ent. J Am Acad Orthop Surg. 2002;10:177 –187. Pell RF IV, Khanuja HS, Cooley GR. Leg pain in th e run n in g ath lete. J Am Acad Orthop Surg. 2004;12:396 –404. Post WR. An terior knee pain: diagn osis an d treatm en t. J Am Acad Orthop Surg. 2005;13:534 –543. Rih n JA, Ch a PS, Groff YJ, et al. Th e acutely dislocated kn ee: evaluation and m anagem ent. J Am Acad Orthop Surg. 2004;12:334 – 346.

Knee Arthroplasty John A. Johansen

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Brian G. Evans

INTRODUCTION Osteoarthritis (OA) of the knee is a degenerative condition that affects a large n um ber of people during the aging process and is by far th e m ost com m on cause of kn ee pain in those older than 50 years. Pain tends to be progressive and is often debilitatin g, th us leading to a sign ifican t decline in the quality of life in these individuals. Wh ile there are m any nonoperative treatm ent options and joint-sparing procedures available for th e m an agem en t of early OA, th e gold stan dard for treatm ent of end-stage OA is total knee arth roplasty (TKA). Curren tly, th ere are approxim ately 200,000 total kn ee replacem en ts don e in th e Un ited States an n ually, an d this num ber can be expected to increase substantially as the population ages. This chapter will serve as a com preh en sive review of th e diagn osis an d treatm en t of OA of the knee and th e expected outcom es and complications of TKA.

ANATOMY Th e osseous an atomy of th e kn ee con sists of th e proxim al tibia, distal fem ur, and the patella, which com bin e to form three compartm ents in the knee: m edial, lateral, an d patellofem oral. (Fig. 18.1) Th e m edial compartm en t of th e kn ee is form ed by th e articulation between the m edial fem oral condyle and the m edial tibial plateau, wh ereas the lateral compartm en t is form ed by the lateral fem oral condyle and the lateral tibial plateau. Th e m edial an d lateral m en isci are attach ed to th e proxim al tibia in th e respective com partm en ts an d fun ction m ainly to increase the surface area for weigh t-bearing (Fig. 18.2). By decreasing the stress transm itted to the articular surface on both the distal fem ur an d proxim al tibia, these m enisci help preserve the joint surface. Biom echan ical studies h ave indicated th at there is approxim ately a 300% in crease in con tact pressures on th e articular cartilage following m eniscal rem oval.

Th e patellofem oral compartm en t is form ed by th e articulation between th e troch lea, wh ich is located on th e an terior aspect of th e distal fem ur, an d th e patella. Th e patella is a sesam oid bon e located with in th e ten don of the quadriceps m echanism and is composed of m edial and lateral facets. Th e lateral facet is typically broader, wh ereas the m edial facet is m ore acutely oriented in relation to the troch lea (Fig. 18.3). Th e un dersurface of the patella contain s th e th ickest layer of articular cartilage in th e h um an body. Th e troch lear groove is located between th e con dyles an teriorly on th e distal fem ur an d h as both a m edial an d a lateral rim . The lateral rim is frequently m ore prom in ent, allowin g for proper patellar trackin g with flexion an d exten sion of th e kn ee.

BIOMECHANICS Th e m ech an ical axis of th e lower extrem ity exten ds from th e cen ter of rotation of th e h ip to th e cen ter of th e an kle joint an d norm ally crosses the knee joint in the lateral th ird of th e m edial tibial plateau. However, th e an atom ic axis is in 5 to 7 degrees of valgus, as the fem oral shaft exten ds m ore laterally th an th e cen ter of th e fem oral h ead (Fig. 18.4). Wh en th e kn ee is loaded, the m edial compartm ent experiences 60% of the weight-bearin g stress, whereas th e lateral compartm en t experien ces 40%. Th is differen ce in the applied load in the n orm al knee is th e reason the m edial tibial plateau an d the m edial fem oral con dyle are larger th an the lateral side. Patien ts with sign ificant an gular deform ity in th e kn ee h ave altered weigh t-bearin g, wh ich results in in creased stress in th e m edial (with varus or bowlegged deform ity) or lateral (with valgus or knock-knee deform ity) compartm en t. Th e in creased stress frequen tly results in early arth ritis in th e affected compartm en t. Th e h igh est join t forces, h owever, are foun d in th e patellofem oral articulation , as forces up to 5 to 8 tim es body weigh t can be n oted for activities such as stair clim bin g an d jumpin g. Th e fun ction of th e patella is predom in an tly to

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Lateral collateral ligament Ant. cruciate ligament

Post. cruciate ligament Medial collateral ligament Medial meniscus

Lateral meniscus

Figure 18.1 Diagram of the knee joint with the patella and cap-

sule removed. The medial compartment contains the medial meniscus, the lateral compartment contains the lateral meniscus, and the patellofemoral compartment is anterior to the distal femur. (Reproduced with permission from Koopman WJ, Moreland LW. Arthritis and Allied Conditions: A Textbook of Rheumatology. 15th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)

provide a m ech an ical advan tage to th e quadriceps m uscle durin g kn ee exten sion . Th e patella m oves in th e lin e of pull of th e quadriceps furth er away from th e cen ter of rotation of th e kn ee, th ereby actin g as a lever an d reducin g th e force required to exten d th e kn ee. Patien ts wh o h ave h ad a patellectomy due to arth ritis, traum a, an d oth er causes are n oted to h ave approxim ately a 30% reduction in kn ee exten sion stren gth.

Figure 18.3 Bilateral axial views of the patella. Note the broad

lateral facet in relation to the relatively acutely angled medial facet. Also note the relative prominence of the lateral rim of the trochlea. (Reproduced with permission from Chapman MW, Szabo RM, Marder R, et al. Chapman’s Orthopaedic Surgery. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2001.)

to 15% of people older th an 60 years. Th is tran slates to approxim ately 26 m illion people in th e Un ited States alon e, with m ore th an 200,000 total kn ee replacem en ts bein g perform ed annually in this country and m ore than 500,000 worldwide. OA causes a substan tial physical burden on th e population as approxim ately 80% of th ese patien ts h ave som e degree of m ovem ent lim itation, with up to 25% having difficulty perform ing routine daily activities. It also leads to significant reduction in job productivity with reports in dicatin g th at patien ts with kn ee arth ritis m issed up to 2 weeks per year of work because of th eir con dition . Th e econ om ic burden of th e disease is also quite rem arkable. Wh en in cludin g OA of all join ts, it is estim ated th at th e cost in the Un ited States is $60 billion per year, whereas job productivity lost costs anywh ere from $3 billion to $10 billion . In fact, OA is secon d on ly to isch em ic h eart disease as a cause of work disability.

Risk Factors

OA OF THE KNEE OA, or degen erative join t disease, of th e kn ee is an extrem ely com m on con dition th at affects approxim ately 10%

OA is ch aracterized by disruption of th e h igh ly organ ized articular cartilage overlying the subch ondral bone an d can be caused by differen t factors. Th e first an d th e m ost com m on type is prim ary, or idiopathic, degenerative arthritis,

Figure 18.2 Superior surface of the tibia with

superimposed medial and lateral menisci. (Reproduced with permission from Chapman MW, Szabo RM, Marder R, et al. Chapman’s Orthopaedic Surgery. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2001.)

Chapter 18: Knee Arthroplasty

Figure 18.4 Mechanical and anatomic axes of the knee. The me-

chanical axis goes from the center of the femoral head to the center of the ankle. The anatomic axis is along the femoral and tibial shafts and forms approximately a 7-degree angle to the mechanical axis. (Reproduced with permission from Chapman MW, Szabo RM, Marder R, et al. Chapman’s Orthopaedic Surgery. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2001.)

an d in this group, the m ost important risk factor is age. Th is is a con dition caused by repetitive “wear an d tear’’ on the joint, so as tim e progresses, it tends to worsen. Prim ary OA is rare in th ose youn ger th an 40 years, but after th e age of 60 years, it becom es quite com m on, with approxim ately 60% of people dem onstratin g radiographic sign s of arth ritis. Th ere can also be a gen etic predisposition , as

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there is a m uch higher rate of occurrence in first-degree relatives. O besity is also com m on ly associated with OA, as patien ts wh o are overweigh t put a greater load on th e weight-bearing joints of the lower extrem ities, wh ich tends to accelerate wear. Wom en ten d to be affected m ore often than m en. Th ere are several secon dary causes of OA. Posttraum atic OA occurs from prior in jury to th e articular surface an d can potentially affect a m uch youn ger patient population. Previous in traarticular fracture to th e distal fem ur, proxim al tibia, or patella will often lead to degen erative disease if an atom ic align m en t of th e extrem ity an d articular surface is not m aintained. At th e tim e of th ese injuries, the articular cartilage is dam aged an d often left with irregularities th at can lead to asym m etric loadin g an d accelerated articular cartilage in jury. Th erefore, on e of th e m ain stays in th e operative treatm en t of articular fractures is an atom ic restoration of th e join t surface. Ligam entous injuries can also lead to accelerated joint degen eration , alth ough th e m ech an ism is som ewh at un clear. Anterior cruciate ligam en t (ACL) in juries have been observed to lead to early kn ee degen eration , but it is n ot kn own whether this is caused by the chon dral injury sustain ed at th e tim e of th e traum atic even t or wh eth er it is from th e subsequen t in stability of th e kn ee. It is m ost likely a com bin ation of th e two, but alth ough th e in jury cannot be reversed, it is possible to lim it future instability. Th erefore, on e m ajor reason to recon struct th e ACL is to lim it th e furth er in jury to th e ch on dral surfaces by stabilizin g th e knee. Meniscal tears are an oth er important in jury to con sider, as th e m en isci fun ction to provide a broader weigh t-bearin g surface between th e proxim al tibia an d distal fem ur. Treatm en t of m en iscal tears is often by arth roscopic m en iscectomy, wh ich drastically alters th e force experienced by the articular cartilage. Therefore, prior m en iscectomy is a well-kn own risk factor for th e developm en t of OA. Deform ities, som e of wh ich start in ch ildh ood, can also place a patien t at risk for OAat a youn g age. Osteoch on dritis dissecan s causes ch on dral dam age m ain ly in teen agers an d can be very difficult to m anage. Blount’s disease or any oth er con dition th at leads to m alalign m en t of th e lower extrem ities places on e at risk. A kn ee th at develops sign ificant varus alignm ent will lead to wear on the m edial side of th e join t, wh ereas valgus align m en t will cause wear on the lateral side.

Pathophysiology Kn ee OA is felt to occur because of repetitive stresses placed on th e join t over tim e, wh ich gradually leads to a breakdown of th e articular cartilage. Th is process begin s as a sim ple softenin g of th e chondral surface and is followed by fraying, which will eventually lead to enough articular cartilage destruction to expose the subchondral bone. Once the subchon dral bone is directly experiencing the weigh t-bearin g stresses, m icrofractures begin to appear in

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its surface, wh ich in turn lead to th e developm en t of subch on dral cysts. Th in n in g of th e cartilage also m an ifests itself as a narrowing of the joint space, which in turn leads to a subtle degree of in stability in th e kn ee. Th e bon e’s response to this phenom enon is to form osteophytes, which are simply areas of reactive bon e form ation th at act to stabilize th e join t. Th e clin ical effect of ch on dral wear is th e developm en t of pain in addition to possible m alalign m en t an d loss of m otion . Malalign m en t is th e result of asym m etric wear, m ost com m on ly in th e m edial compartm en t, thus causing a varus deform ity, whereas m otion loss results from capsular contracture, which typically occurs posterior an d appears clin ically as a loss of term in al exten sion .

PATIENT EVALUATION Clinical Presentation/History Patien ts with OA can present in a variety of ways, but m ost com m only, they complain of kn ee pain that has been insidious in onset, often over th e course of m any years. Frequen tly, th is is associated with stiffn ess an d in term itten t swelling of the knee th at is typically worse with activity an d relieved with rest. Patien ts will also com m on ly state that they have been getting progressively m ore “bowlegged’’ over th e course of tim e. When a youn ger patien t presen ts with com plain ts th at seem consistent with degenerative knee pain, it is also im portan t to take a th orough h istory to determ in e th e probable cause. First, th e physician sh ould con sider poten tial sources of referred pain, wh ich can in clude either th e lum bar spin e or th e h ip. Lum bar disc disease can frequen tly cause radicular symptom s that m an ifest as knee pain, while hip pathology can also be referred to the kn ee along th e course of the obturator n erve. A history of injuries or surgeries on th e kn ee, such as in traarticular fractures, ligam en tous or m en iscal tears, or prior kn ee surgery, is importan t as th ese are poten tial risk factors. As previously m en tion ed, gen etics also plays a prom in en t role in th e developm en t of OA, so fam ily h istory of early-on set arth ritis sh ould be determ in ed. On e sh ould also take a complete m edical h istory as oth er con dition s such as gout, rh eum atic diseases, recen t in fection , an d h em oph ilia can cause kn ee pain an d lead to arth ritic ch an ges.

Physical Examination Th e physical exam in ation sh ould always begin with in spection , an d th ere are several im portan t th in gs to look for in the degenerative kn ee. First, the static longitudinal alignm en t of th e lower extrem ity sh ould be observed in th e standing patien t. Th e norm al alignm en t of the lower extrem ity is approxim ately 5 to 7 degrees of valgus, an d degen erative ch an ges can cause eith er varus or valgus m alalign m en t, with varus m alalign m en t bein g m ore com m on

Figure 18.5 This patient is seen to have significant varus alignment of the left lower extremity when observed in the standing position. (Reproduced with permission from Chapman MW, Szabo RM, Marder R, et al. Chapman’s Orthopaedic Surgery. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2001.)

(Fig 18.5). The exam iner should also observe the patients gait, which is frequently seen to be antalgic, m eaning that there is a shortened stance phase on the affected extrem ity. A lateral th rust is also com m on ly seen due to th e attenuation of the lateral collateral ligam ent (LCL). This typically occurs in patien ts with a lon g-stan din g varus deform ity of th e kn ee (Fig. 18.6). Medial th rusts can also be seen with valgus deform ity but are m uch less com m on in th e osteoarth ritic patien t. Palpation will often reveal the presence of an effusion, wh ich is presen t durin g an exacerbation , or an “arth ritic flare.’’Medial an d lateral joint line ten derness is com m only presen t, with m edial ten dern ess bein g m ore often associated with varus deform ity. Range of m otion should also be assessed an d is frequen tly lim ited. A flexion con tracture (loss of passive extension) is seen early, an d as th e con dition progresses, a loss of flexion is also appreciated. During the range of m otion, patellofem oral crepitus is com m only observed.

Imaging Plain radiograph s are th e on ly im agin g study n ecessary for the diagn osis of OA, with the classic findings being joint space narrowing, osteophyte form ation, subch ondral cysts, and subch ondral sclerosis (Fig. 18.7). The


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evaluation sh ould start with a weigh t-bearin g an teroposterior (AP), lateral, an d sun rise view of th e kn ee. Th e n eed for weigh t-bearin g radiograph s can n ot be overem ph asized, as th ey m ore accurately sh ow th e con dition of th e join t wh en placed un der a load. It is n ot un com m on for significant varus align m ent and m edial join t space n arrowin g to be m issed on n on –weigh t-bearin g radiographs (Fig. 18.8). Lateral views show both the tibiofem oral and patellofem oral joints, whereas the sun rise view m ore th orough ly im ages th e patellofem oral join t. O ften with early arth ritis th e weigh t-bearin g AP view will fail to sh ow any sign ifican t changes as th is loads only the anterior and m iddle weight-bearing portions of the tibial fem oral joint. A 30- to 45-degree weight-bearing posteroanterior flexion view can be used to m ore accurately assess the m iddle and posterior aspects of th e fem oral con dyles. Th is study will frequently sh ow a m ore significant arthritis th an what was visualized on the stan dard AP view (Fig. 18.9). Figure 18.6 A lateral thrust is seen in the stance phase of gait

in a patient with a long-standing varus deformity, whereas a medial thrust can be seen with a valgus deformity. (Reproduced with permission from Chapman MW, Szabo RM, Marder R, et al. Chapman’s Orthopaedic Surgery. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2001.)

Figure 18.7 Osteoarthritis of the knee. Note the asymmetric

joint space narrowing, osteophyte formation, and the subchondral sclerosis on the medial side of the joint. (Reproduced with permission from Weinstein SL, Buckwalter JA. Turek’s Orthopaedics: Principles and Their Application. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)

Differential Diagnosis Th e differen tial diagn osis for OA in cludes oth er con dition s th at can lead to kn ee pain an d swellin g. Th ese in clude in flam m atory arth ritis, crystallin e arth ropathy, septic arthritis, and osteonecrosis. Th e m ain con dition s to con sider are th e in flam m atory arth ritides, the m ost com m on of which is rheum atoid arth ritis. However, oth er con ditions include lupus, ankylosing spondylitis, Reiter’s syn drom e, psoriatic arthritis, and arthritis associated with inflam m atory bowel disease. Th ese con dition s can all presen t sim ilarly with an in sidious on set an d lon g duration of kn ee pain . However, th ere are several important differences. First, m any of these patients will have involvem ent of m ultiple joints, and they classically h ave pain th at is worse with rest an d relieved by activity. Bilateral knee involvem ent can certainly be seen with OA, but it is n orm al in th ose with rh eum atoid disease. O n e m ust also be cogn izan t of th e review of system s, as inflam m atory arthritis can be associated with conditions involving the eyes, skin , an d gastrointestinal tract and m ay also be associated with a fam ily history. Physical exam in ation is important for distin guish in flam m atory arthritis, as again, m ultiple joints are frequently involved. In addition, soft tissue bogginess an d swelling is m ore com m on th an a true effusion . Valgus align m en t of th e kn ee is also associated with inflam m atory arthritis, although it can be seen in th e osteoarth ritic patien t. Radiograph ic changes are also different, as the classic changes in rheum atic disease include sym m etric joint space narrowing, osteopenia, and periarticular erosion s, alon g with th e absen ce of osteophyte form ation (Fig. 18.10). The con servative treatm ent options between th ese two con dition s are sign ifican tly differen t, alth ough th e gold stan dard for en d-stage disease is total kn ee replacem en t in both in stan ces. Crystalline arthropathies, such as gout and pseudogout, m ust also be considered, particularly in those who

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A

B Figure 18.8 (A) Supine anteroposterior in a patient presenting with knee pain. (B) Weight-bearing

radiograph of the same patient taken a short time later. Note the medial joint space narrowing and the obvious varus alignment, thus confirming the diagnosis of osteoarthritis. (Reproduced with permission from Koopman WJ, Moreland LW. Arthritis and Allied Conditions: A Textbook of Rheumatology. 15th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)

Figure 18.9 Technique for the 45-degree posteroanterior flexion

weight-bearing radiograph of the knee. (Reproduced with permission from Chapman MW, Szabo RM, Marder R, et al. Chapman’s Orthopaedic Surgery. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2001.)

Figure 18.10 Rheumatoid arthritis of the knee. Note the large

subchondral cysts, symmetric joint space narrowing, and the generalized osteopenia. There is also a complete absence of osteophytes. (Reproduced with permission from Koopman WJ, Moreland LW. Arthritis and Allied Conditions: A Textbook of Rheumatology. 15th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)


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Figure 18.11 Pseudogout. Note

the typical punctate and linear deposits of calcium in both the medial and lateral menisci. (Reproduced with permission from Koopman WJ, Moreland LW. Arthritis and Allied Conditions: A Textbook of Rheumatology. 15th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2005.)

have a h istory of gout in other joints. Gout is caused by the buildup of sodium urate crystals in the joint, which leads to significant pain. However, the pain often presents m ore acutely than degenerative joint disease. An effusion is often presen t, and diagnosis is definitively m ade by arthrocentesis with the presence of negatively birefringent crystals in the aspirate. Pseudogout is caused by a buildup of calcium pyroph osph ate crystals, wh ich are often seen as calcifications in th e m en isci on radiograph s (Fig. 18.11). Diagn osis is by presen ce of rh om boid-sh aped crystals on aspiration. Septic arth ritis is possible, alth ough th is sh ould be seen an d diagnosed on a m uch m ore acute basis. These patients will h ave an acute on set of pain an d swellin g with an in ability to m ove th e kn ee. Diagn osis is by the presence of m ore than 75,000 wh ite blood cells in the synovial fluid. Osteonecrosis can also be considered, although it too is seen m uch m ore acutely. Known as the “h eart attack of the knee’’, osteon ecrosis typically occurs in the m edial fem oral con dyle and will cause persisten t pain.

NONOPERATIVE TREATMENT Treatm ent of OA of the knee is sim ilar to the m anagem en t of OA in oth er join ts, so th ere are m ultiple n on surgical option s available. Th e first-lin e th erapy is typically n on steroidal an ti-inflam m atory drugs (NSAIDs), which fun ction by reducin g pain and swellin g associated with the knee. Although all NSAIDs function in a sim ilar fashion , there is a wide variation to patient response to each individual m edication. Th erefore, at m in im um , two to three differen t NSAIDs sh ould be attem pted before aban don in g th is treatm ent option. One m ust also be cognizant of the gastrointestinal side effects, as patients with a history of ulcers and gastroesoph ageal reflux should not be given these m edications without consultation from the their prim ary caregivers. Other oral m edication s that have been tried include the recently popularized over-the-counter supplem en ts glucosam in e an d ch on droitin sulfate. Th ese

substances are part of the building blocks of articular cartilage an d work th eoretically by in testin al absorption of th e substances, followed by their incorporation in to the articular cartilage of th e dam aged join t. A recen t large clin ical trial con ducted at th e Nation al In stitutes of Health in dicated that there was no clin ical ben efit to using th ese products, but th ere is certain ly an ecdotal eviden ce th at th ey lead to symptom atic improvem en t in som e patien ts. With th at said, th ere does n ot appear to be any h arm , other th an cost, to usin g th ese products, so th ey are certain ly worth tryin g in th ose wh o h ave been un able to get symptom atic relief via oth er m eth ods. Th e secon d-lin e treatm en t is th e use of in tra-articular corticosteroid injections, which are m ainly used for controllin g th e acute exacerbation s of pain . Th ese m edication s function as strong anti-inflam m atory agents and are used to “quiet down ’’patien ts’pain in an effort to restore th em to their baselin e level of discom fort. However, wh en overutilized, cortison e h as actually been sh own to accelerate degeneration of the articular cartilage. Therefore, steroid injection s sh ould n ot be used to con trol baselin e pain an d typically sh ould n ot be given m ore th an th ree tim es over th e course of a year. If a patien t is requiring m ore th an th is, oth er treatm en t option s sh ould be explored. Asecon d form of in jection s th at are used in clude th e hyaluron ic acid derivatives. Hyaluron ic acid is th e substan ce th at provides the lubricating fun ction in norm al syn ovial fluid and is often deficien t in th e arth ritic kn ee. Th ese in jection s are theoretically used to decrease the coefficien t of friction between th e opposin g ch on dral surfaces, th us leadin g to less degen eration of th e cartilage. Th is h as sh own som e clin ical efficacy in certain trials, alth ough basic scien ce proof of its m ech an ism is lackin g. However, th ese in jection s h ave also been sh own to cause m in im al h arm , oth er th an th e sm all risk of in fection, so they are a reasonable option in the patient who is attempting to delay surgery. Physical th erapy can be very h elpful in th e treatm en t of arth ritis of th e kn ee. Th e soft tissue sleeve is im portan t to kn ee fun ction , so its optim ization can dim in ish th e symptom s of osteoarth ritis. Therapy should be directed at

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m ain tain in g th e ran ge of m otion of th e kn ee an d stren gth en in g th e quadriceps an d h am strin g m uscles. However, in the late stages of degenerative disease, therapy can worsen the symptom s and sh ould be lim ited only to the patient’s toleran ce. Assistive devices such as a cane, crutch, or walker m ay also be h elpful in th e m an agem en t of OA. Th ese aids can lim it th e stress across th e pain ful kn ee an d improve th e patien t’s walkin g toleran ce. Last, if all else fail, patien ts m ay m odify th eir activities. Th is in cludes elim in atin g activities that overload the joint, som e of which include run ning or playin g ten n is, an d ch an gin g to less dem an din g activities such as swim m in g. Patien ts with degen erative join t disease are also frequen tly overweigh t, so weigh t loss can be an effective m eth od to reduce sym ptom s by reducin g th e stress experien ced by th e join t.

SURGICAL TREATMENT Non operative m an agem en t can in clude som e or all of th e therapies previously m entioned; h owever, as pain con tinues to progress, lim itation of activities will in crease. Wh en the patient is unable to obtain acceptable symptom atic relief with n on operative care, surgical treatm en ts sh ould be discussed. Th ese can be broken down in to procedures th at spare the patien t’s native articular cartilage and those that rem ove or replace it. Th e tim in g of th e surgery depen ds on the patient’s situation . In the younger patient with un icom partm en tal disease, an early in terven tion m ay be n ecessary to preven t rapid progression of th e disease. However, in th e patien t older th an 60 years with tricom partm en tal disease, there is little chan ge in the complexity or the outcom e of a total kn ee replacem en t with advan ced disease, so tim in g sh ould be based on the patien t’s symptom s.

Arthroscopy Arthroscopy of the kn ee is by far the simplest operative treatm en t th at can be ch osen for m an agem en t of th e arth ritic kn ee. Th is is an outpatien t procedure th at can gen erally be com pleted in less th an 30 m in utes, an d th e com plete recovery tim e is often less th an 2 weeks. However, its effectiven ess is con troversial. Th e procedure is don e sim ply to “clean out” th e kn ee by rem ovin g any loose ch on dral flaps, debris in th e join t, or torn or frayed m en iscus. Arthroscopy cannot be used to off-load or replace any of the diseased cartilage and exists only to delay the need for m ore in vasive in terven tion . Several well design ed studies have indicated that th ere is no ben efit to arthroscopy in th e degen erative kn ee, in dicatin g th at som e patien ts m ay even get worse, wh ereas oth ers h ave sh own th at it is an effective way to postpone a knee replacem ent by up to several years. Th e actual results are likely som ewh ere in between th ese extrem es. Th ere is good eviden ce th at doin g an arth roscopic debridem en t on patien ts with advan ced OA is un likely to

provide any substan tial relief; h owever, if don e on patien ts with earlier-stage disease, it will often m ake th em symptom atically better for variable periods.

Osteotomy Angular deform ities of the knee com m on ly occur in patients with OA. This m alalignm ent causes an asym m etrical loadin g between the m edial and lateral compartm ents, thus leading to accelerated degenerative changes on the overloaded side. Varus deform ity is th e m ost com m on in OA, an d it can lead to in creased stress on th e m edial com partm en t. Wh en th is occurs th ere are ben efits to addressing just the diseased compartm ent with surgical intervention. However, it is importan t to recognize th at the vast m ajority of patients presenting with a varus deform ity in an arthritic knee have disease that also involves the other com partm en ts. With th at said, ch on dral-sparin g procedures are frequently indicated in younger patients as th ey can be used to delay th e n eed for total kn ee replacem en t. Th e best option for treatin g un icom partm en tal m edial disease in th e younger patient (< 60 years) is by high tibial osteotomy (HTO). HTO is don e to off-load th e diseased m edial com partm en t by correctin g, an d in fact overcorrectin g, the m alalignm ent of the lower extrem ity by placing it back into valgus (Figs. 18.12 and 18.13). Th e prim ary ben efit of doin g an HTO as opposed to a TKA is th at it preserves patien ts’ n ative articular cartilage, thus elim inating the concern about m aterial wear seen with TKA. Th is leaves patien ts with n o activity restriction s following un ion of the osteotomy site, which is particularly im portan t in youn ger active patien ts wh o are likely to quickly wear out a prosth etic join t. Th e two prin cipal drawbacks to HTO are th at it sh ould be used on ly in th ose with un icompartm ental disease and that the results of the procedure progressively deteriorate with tim e. HTO fun ction s by transferrin g the weight-bearing load over to the lateral compartm ent, so it is important to determ ine the condition of th e lateral side preoperatively. If there are already degen erative ch an ges th ere, it is likely th at th e procedure will fail because of in creased lateral-sided pain . Regardin g longevity, n ew instrum entation h as in creased th e average survival rates of th is procedure to approxim ately 10 years, but th is is n owh ere n ear th e proven lon g-term results th at are seen with TKA. For this reason, HTO is generally discouraged in older patien ts with a m ore sedentary lifestyle in which TKA is m ore likely to give them m ore complete an d endurin g success. Valgus producing osteotom ies (for varus deform ity) are perform ed as eith er m edial open in g wedge or lateral closing wedge procedures. Lateral closing wedge osteotom ies were described first an d are don e by takin g a wedge of bon e out of th e lateral border of th e proxim al tibia. Th e gap is then closed and typically held with intern al fixation (Fig. 18.12). However, m edial open ing wedge osteotom ies are currently used m ore frequently as they allow for easier


743

A

Figure 18.13 Medial opening wedge high tibial osteotomy following correction with placement of internal fixation. Bone graft substitute has been used to fill in the osteotomy site.

B Figure 18.12 High tibial lateral closing wedge valgus osteotomy: (A) after the bone wedge is removed and (B) following closing of the wedge and internal fixation to correct a varus deformity. (Reproduced with permission from Chapman MW, Szabo RM, Marder R, et al. Chapman’s Orthopaedic Surgery. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2001.)

adjustm ent at the osteotomy site (Fig. 18.13). With open ing wedge procedures, on ly one saw cut is m ade, and the bon e is levered open wh ile keepin g th e lateral cortex in tact. Th is osteotomy is also typically h eld in place with in tern al fixation devices. Valgus deform ities can also be corrected with a varusproducin g osteotomy, alth ough th is is m uch less com m on . Th e tech n ique of ch oice is typically a distal fem oral osteotomy an d can be eith er a lateral open in g wedge or a m edial closing wedge procedure.

Unicompartmental Knee Arthroplasty Unicompartm en tal knee arth roplasty (UKA) is an oth er treatm ent option for those with single compartm ent disease. Just as with th e HTO, it is used m ost com m on ly

in th ose with a varus deform ity that has led to isolated degen eration of th e m edial com partm en t. Th is procedure en tails a resurfacin g, or replacem en t, of th e degen erative com partm en t by rem ovin g th e n ative articular cartilage from th e m edial fem oral condyle and m edial tibial plateau and replacing it with prosthetic components (Fig. 18.14). Th e prim ary advan tage of UKA over HTO is th at it allows for a m uch faster recovery and perm its im m ediate weightbearin g in th e postoperative period. However, it does replace a portion of th e patien t’s n ative join t with prosth etic com pon en ts, wh ich are in turn susceptible to wear, particularly in th ose wh o are m ore active. Wh en com parin g UKA with TKA, th e prim ary advan tage is th at th e en tire join t is n ot replaced. Patients’ native cruciate ligam en ts are m aintain ed, leadin g to m ore n atural kin em atics th an th at following TKA. Furtherm ore, it is less in vasive with a sm aller incision, there are fewer short-term complications, an d the early recovery an d reh abilitation is felt to be faster. However, th e m ajor disadvan tage is th at th e lon g-term survivorsh ip h as been un able to approach the well-docum ented track record of total knee replacem en t. UKA is a procedure th at certainly has a role in the m anagem ent of OA, but it is important to adhere to strict surgical in dications to achieve success. First, and m ost importan t, patien ts m ust h ave isolated on e compartm en t disease, as failure to address other diseased compartm ents with surgery will lead to con tinued pain. Also, patients younger

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Figure 18.14 Unicompartmental knee arthroplasty of the medial

compartment. (Reproduced with permission from Lotke PA, Lonner JH. Master Techniques in Orthopaedic Surgery: Knee Arthroplasty. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2003.)

than 60 years, or active patients older than 60 years, should be con sidered for HTO in th e settin g of un icom partm en tal disease, as th e prosth etic compon en ts used in UKA are likely to fail early in th is coh ort. Oth er con train dication s to UKA include ACL deficiency, fixed varus deform ity of the knee, knee flexion contractures, an d inflam m atory arthritis. Again , UKAdoes h ave a role in a sm all group of patien ts, but in m ost cases, it is difficult to argue with th e proven success rate of TKA in the degenerative knee. While UKAof th e m edial com partm ent is the m ost com m on partial join t replacem en t, th ere are various oth ers th at can be done. Isolated lateral disease is less com m on, but when present, one can con sider either a distal fem oral osteotomy or a lateral UKA. Patellofem oral arth ritis is also seen, an d in rare circum stances, an isolated patellofem oral replacem en t can be used. In addition , th ere h ave been bicompartm en tal replacem ents designed to replace the m edial an d patellofem oral compartm en ts, but at th is tim e, lon g-term data are lackin g.

Knee Arthrodesis Arthrodesis, or fusion, of the knee is another seldom -used option for the osteoarth ritic kn ee (Fig. 18.15). This procedure is very effective for pain relief, but because it does so by completely elim inatin g all knee m otion, it is an un appealin g option . It does allow for full weigh t-bearin g an d am bulation , alth ough th e resultan t gait pattern is sign ifican tly abn orm al. At th is tim e, fusion is con sidered on ly in youn g active patien ts, particularly in physical laborers, or in th ose with failed and non salvageable prior join t replacem en t.

Figure 18.15 Right knee arthrodesis done with a modular in-

tramedullary nail. (Reproduced with permission from Lotke PA, Lonner JH. Master Techniques in Orthopaedic Surgery: Knee Arthroplasty. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2003.)

TOTAL KNEE ARTHROPLASTY Th e gold stan dard for th e treatm en t of en d-stage OA of the knee is total kn ee replacem ent (Fig. 18.16). This is an extrem ely com m on operation , an d it h as a proven track record for both survival an d pain relief. Th e average age of patien ts un dergoin g kn ee replacem en t in th e Un ited States is approxim ately 65 –70 years, but it is often used in those wh o are m uch youn ger an d older. As m en tion ed earlier, there are several surgical alternatives, but n one h as been able to approach the lon g-term results of TKA.

Indications Th e m ajor in dication for TKA is th e presen ce of persisten t m echanical knee pain that can no longer be con trolled by oth er n on surgical or surgical m ean s. Th e pain is m ost typically caused by OA, either prim ary or posttraum atic, but it can also be from rheum atoid arth ritis or other inflam m atory disorders. Patients will benefit from a course of con servative m anagem ent, but the progressive nature of the disease eventually results in m any patients requiring a surgical treatm en t. Total kn ee replacem en t is an elective procedure, so th e decision for wh en to proceed with th e operation is left up to


745

Figure 18.16 Postoperative radiograph of a patient who had bilateral total knee arthroplasties.

patien ts. Wh en patien ts are experien cin g en ough pain an d functional lim itation that they feel it is worthwh ile to undergo a m ajor operation with a prolon ged recovery, th en it is tim e for the surgery. Radiographs can also be som ewhat m isleading, as som e patients with rather m ild-appearing radiograph s will h ave severe pain , wh ereas oth ers with severe changes on radiograph will be functioning quite well. With that said, patients should be in form ed that th e purpose of th e surgery is to relieve pain , an d it is able to do this effectively in the vast m ajority of cases.

Surgical Procedure Th e kn ee join t is approach ed th rough an an terior m idlin e incision, followed by a m edial parapatellar arthrotomy. The patella can th en be everted, wh ich in turn exposes th e en tirety of the knee joint. At that point, the proxim al tibia is cut perpen dicular to th e lon g axis of th e sh aft of th e tibia an d the fem oral articular surface is cut by using specific guides to rem ove th e fem oral troch lea an d th e distal an d posterior fem oral con dyles. Th e patella is norm ally resurfaced as well by resecting th e articular surface with a cut parallel with its an terior surface. The ACL is rem oved, wh ereas the m edial collateral ligam ent (MCL) an d the LCL are retain ed and carefully balanced. The posterior cruciate ligam ent (PCL) can be either resected or retained, depen ding on the design of the implant ch osen. This allows for a classification of kn ee design s in to two types: posterior cruciate retain ing and posterior cruciate substituting designs. Use of the

two design s is approxim ately equal in th e Un ited States. Th ose who prefer th e retain in g design s argue th at keeping the PCL allows for a m ore biom echanically norm al kn ee m otion , particularly in late flexion , wh ereas th ose wh o are again st it claim th at in th e osteoarth ritic kn ee, th e PCL is already diseased an d sh ould be resected. Substitutin g designs replace th e PCLwith a m echan ical block that prevents posterior tran slation of th e tibia (Fig. 18.17). Th e compon en ts used in TKAare a com bin ation of m etal alloys an d polyethylen e (Fig. 18.18). Th e fem oral an d tibial sides of th e join t are typically resurfaced with m etal alloys sh aped to fit th e surfaces, wh ile th ere is an in terven in g polyethylen e com pon en t between th em . Th erefore, the bearing surfaces used for TKA at this tim e are m etal on polyethylen e. In addition , wh en th e decision is m ade to resurface th e patella, it too is typically don e with an allpolyethylen e compon en t. Metal backin g h as been used for this component, but this led to substantial stress shielding of th e rem ain in g patellar bon e an d later risk for fracture. Th ere h as been a tren d toward n on cem en ted compon en ts in h ip replacem ent surgery, but kn ee replacem ent is typically don e with all of th e com pon en ts cem en ted. Polym ethylm eth acrylate is th e substan ce th at is used as bon e cem en t, and it h olds the components in place by interdigitatin g with th e adjacen t m etaphyseal bon e. Non cem en ted compon ents, which h ave a porous surface for bon e ingrowth, have been associated with a higher incidence of compon ent loosening in long-term studies, so their use is discouraged. Th is is particularly true on th e tibial side,

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Figure 18.18 The Depuy PFC sigma total knee arthroplasty. (Reproduced with permission from Courtesy of DePuy Orthopaedics, Inc.)

Figure 18.17 Posterior substituting total knee arthroplasty.

When the knee goes into flexion, posterior translation of the tibia is blocked by the polyethylene post abutting the distal femur. (Reproduced with permission from Chapman MW, Szabo RM, Marder R, et al. Chapman’s Orthopaedic Surgery. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2001.)

where th e h igh est force on the com pon ents fixation is experienced due to the shear stress that felt during knee flexion. Th erefore, if n on cem en ted compon en ts are ch osen , th ey sh ould be lim ited to th e fem oral side of th e arth roplasty.

Postoperative Recovery Th e patien t is m obilized in to a ch air on th e first postoperative day, an d full weigh t-bearin g m ay be allowed im m ediately. However, a kn ee im m obilizer sh ould be used to protect th e kn ee from acute flexion wh ile walkin g, an d this is contin ued until th e quadriceps function returns. The critical elem ent of the postoperative therapy is the restoration of m otion . If th e m otion is n ot restored with in th e first 3 to 6 weeks, m aturation of th e scar tissue will preven t m ajor gain s in m otion . Many surgeon s elect to use a continuous passive m otion (CPM) m ach ine in the im m ediate postoperative period to en courage m otion , alth ough it h as n ot been sh own to h ave any substan tial impact in the long term . Total h ospital tim e postoperatively in m ost centers averages between 3 and 4 days, an d m ost patients require h om e physical th erapy to con tin ue work on ran ge of

m otion an d am bulation in the first few weeks after surgery. Th e total reh abilitation period after TKA is between 3 an d 6 m on th s, alth ough patien ts are fun ction ally m obile after 2 to 3 weeks.

Outcomes Th e ultim ate goal of all total kn ee replacem en t surgeries is pain relief, an d in m ost cases, it is successful. Th e lon g-term outcom es of th e procedure h ave been well docum en ted in the literature and have repeatedly shown excellent results. Survivorsh ip n um bers for m odern prosth eses are cited as bein g as h igh as 95% at 10 years, 90% at 15 years, an d up to 80% at 20 years. Lon gevity is im proved in th ose older th an 70 years, wom en , an d th ose with an un derlyin g diagn osis of in flam m atory arth ropathy. Youn ger m ale patien ts, h owever, ten d to put m ore stress on th e prosth esis, wh ich leads to earlier an d h igh er rates of compon en t wear an d loosen ing. In addition to impressive longevity of these implants, it m ust also be noted th at in the m ajority of cases, these patien ts will h ave n ear-complete pain relief in addition to sign ificant fun ction al benefits from th e procedure.

Complications Th e m ajority of total kn ee replacem en ts are successful operation s, but there are several com m on and significant com plication s th at n eed to be discussed. Particularly wh en con siderin g th e large volum e of kn ee replacem en ts done, it is important to be fam iliar with the causes of continued pain


an d the m edical complications that can be encountered followin g arthroplasty.

Postoperative Pain Con tinued pain after TKA is seen in less than 10% of patients, and the m ajority of these complaints are from the patellofem oral join t. Th is can be th e result of poor soft tissue align m ent at the tim e of arthroplasty and m ay lead to pain ful subluxation or dislocation of th e patellar com ponent. If inadequate bone is resected from the patella at th e tim e of resurfacing, a m arked increase in th e patellofem oral stress can be noted, an d this m ay lead to pain. Several authors have advocated not resurfacin g the patella for this reason, but studies now dem onstrate a higher rate of patellofem oral com plain ts after TKAwith out patellar resurfacin g. If sign ifican t patellofem oral arth ritis exists at th e tim e of arthroplasty, patients with weigh t m ore than 60 kg an d height m ore than 160 cm will h ave m ore pain postoperatively if th e patella is n ot resurfaced. When evaluatin g th e patien t with pain following TKA, it is important to do a th orough investigation of th e possible causes, and infection m ust always be ruled out. If infection is n ot presen t, then one m ust search for other sources of pain , an d in m any cases, th ere is n ot on e th at is iden tifiable. In th ese in stan ces, th e surgeon sh ould be h esitan t to return to th e operatin g room for revision surgery, as th e success rates are m uch h igh er in th e settin g of a problem th at h as been clearly iden tified preoperatively an d is correctable.

Thromboembolic Disease Th e m ost com m on complication after TKA is th rom boem bolic disease, wh ich can ran ge from deep ven ous th rom bosis (DVT) to fatal pulm onary em bolism (PE). At the presen t tim e, th e rate of DVT identified by ultrasoun d in th e postoperative settin g is approxim ately 5% in patien ts wh o com plain of calf pain . However, studies usin g ven ography in all postoperative patien ts h ave reported rates of DVT ran gin g from 25% to 50%. PE is reported to occur in approxim ately 1% of patien ts, an d th is can poten tially be fatal, alth ough the m ortality risk is only approxim ately 0.01%. In an effort to preven t th ese occurren ces, all patien ts sh ould be given lower extrem ity compressive devices for m echanical prophylaxis and be m obilized on postoperative day 1. Both th ese intervention s have been shown to significantly reduce the n um ber of th rom boem bolic even ts. Th e stan dard of care is for ch em ical prophylaxis to be given as well. At present, there are a variety of m edications from wh ich to ch oose an d th ere is con flictin g eviden ce regardin g their risks and effectiveness. Warfarin (Coum adin) given for 6 weeks postoperatively has the greatest volum e of literature to support its use, alth ough th e in tern ation al n orm alized ratio (INR) needs to be closely m onitored. While Coum adin is undoubtedly effective when the INR is kept at a safe range, it can be difficult to con trol in the outpatient settin g, an d dangerous elevation s of th e INR are a distin ct

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possibility. Th is can lead to bleedin g an d h em atom a n ot on ly at th e operative site but also at oth er location s, in cluding the brain. Low-m olecular-weight heparin form ulation s can also be used, with th e prim e advan tage bein g th at they do n ot require outpatien t m onitoring. In addition to this, recent literature has shown that they provide effective prophylaxis with on ly a 10-day course postoperatively. Disadvan tages of low-m olecular-weigh t h eparin are th at it is contraindicated in patients with renal failure; it com es on ly as an in jection , wh ich m any patien ts do n ot like; an d it h as a ten den cy to cause prolon ged drain age from th e in cision site postoperatively. Aspirin has also been used for DVTprophylaxis due to its ease of adm in istration , alth ough th ere is m in im al data to directly support it for th is in dication . Th rom boem bolic disease is a sign ifican t complication of TKA, an d a h igh in dex of suspicion m ust always be m ain tain ed in th e postoperative period. Any patien t com plain in g of calf pain or sh ortn ess of breath followin g join t replacem en t surgery warran ts furth er workup, an d appropriate treatm en t sh ould be started im m ediately after th e diagn osis is m ade.

Infection Th e m ost devastatin g complication after TKA is deep sepsis, which is estim ated to occur in approxim ately 1% of patien ts. Th e m ost com m on organ ism s are skin flora, prim arily Staphylococcus aureus and S. epidermidis. These organism s often gain entran ce via the relatively thin soft tissue en velope at th e in ferior aspect of th e woun d, wh ich m ust be m on itored in th e early postoperative period. Any area of skin breakdown after TKA should be treated aggressively to preven t deep in fection , particularly in patien ts with prior incisions and in those with diabetes or significant vascular disease. Diagn osis is m ade by history and physical exam ination com bined with laboratory and im aging studies. Patien ts wh o presen t with pain in a previously wellfunction ing arthroplasty should always be worked up for infection, which includes eryth rocyte sedim en tation rate, C-reactive protein level, an d join t aspiration . Radiograph s sh ould be evaluated for th e presen ce of compon en t loosenin g. Early postoperative in fection is less com m on th an late infection, but recognition is critical for optim al treatm ent. If detected with in th e first 3 weeks postoperatively, aggressive open debridem en t, synovectomy, and polyethylen e exchange com bined with intravenous an tibiotics can be successful. However, if th e in fection recurs after debridem en t or if it is detected beyon d 3 weeks, treatm en t m ust in clude rem oval of th e prosth etic compon en ts an d all cem en t. An antibiotic-impregnated cem ent spacer should be placed at th e tim e of debridem en t, wh ich serves as a local depot of antibiotic at the site of the infection and also provides stability to soft tissues durin g treatm en t. After com pletion of a m in im um of 6 weeks of in traven ous an tibiotic th erapy, repeat laboratory studies an d repeat aspiration sh ould be

748


A

B Figure 18.19 (A) Anteroposterior and (B) lateral radiographs showing radiolucent lines around

both the tibial and femoral components indicative of loosening of this total knee arthroplasty. (Reproduced with permission from Lotke PA, Lonner JH. Master Techniques in Orthopaedic Surgery: Knee Arthroplasty. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2003.)

completed, and if these studies are negative, on e m ay proceed with revision total knee replacem ent. However, as a result of th e in evitable scarrin g an d probable bon e loss, the clinical result is comprom ised to som e degree, and the infection rate following revision surgery is significantly higher than th at seen followin g prim ary arth roplasty.

Loosening/Wear While current implan ts h ave sign ifican tly im proved durability, th e lon g-term effect of placin g prosth etic components into the knee joint is the generation of wear particles from th e implan ts. Th is is m ore pron ounced in patients who place m ore stress on th e im plan t, particularly those who are youn ger, m ore active, or obese. In TKA, aseptic loosen in g of th e compon en ts occurs at a low rate, but over the expected survivorship of an implant, it eventually becom es significant. Loosening of components will lead to knee pain, so th e m ost com m on presentation is that of a patient with a well-functionin g implant for m any years who th en develops th e gradual onset of pain , especially with activity. Of n ote, any com ponen t loosen ing prior to 5 years postoperatively should be considered infected until proven oth erwise. Th e diagn osis of loosen in g is m ade radiographically, as areas of implan t loosening will appear as radiolucen t lin es aroun d th e compon en ts (Fig. 18.19). Serial radiograph s will sh ow progression of th e radiolucen t areas an d possibly m igration of th e compon en t. O n ce th e symptom s are severe en ough, revision surgery is gen erally required to provide a stable implan t. Wear in TKA has other sign ifican t effects, particularly in regard to th e polyethylene compon en t (Fig. 18.20). The bearin g surface in TKA is m etal on polyethylen e, an d th e

result of repeated loadin g of th e join t is particulate debris origin atin g from th e polyethylen e. Th e m icroscopic polyethylen e particles are released in to th e local tissues wh ere th ey are in gested by m acroph ages, wh ich attempt to digest the particles with catabolic enzym es and superoxides. Th e debris accum ulates in th e cell, wh ich even tually breaks down and releases the polyethylen e and th e en zym es back in to th e local en viron m en t. Th e release of th e catabolic en zym es in to th e tissue causes osteolysis of th e bon e, wh ich can h ave severe con sequen ces (Fig. 18.21). Loss of bone support can lead not only to prosthetic loosen in g an d clin ical failure but also to sign ifican t weakn ess of

Figure 18.20 Polyethylene just removed from a knee that had

been in place for 6 years. Note the delamination of the polyethylene both medially and laterally. (Reproduced with permission from Lotke PA, Lonner JH. Master Techniques in Orthopaedic Surgery: Knee Arthroplasty. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2003.)


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attempt to restore m otion by “breakin g up’’th e scar tissue. If th e m otion can n ot be restored, particularly if patients are beyon d 6 weeks from surgery, addition al surgery with an open lysis of adh esion s m ay be in dicated.

Instability

Figure 18.21 Lateral radiograph of a total knee arthroplasty

that has been in place for 6 years. Note the extensive osteolysis of the distal femur shown by the arrows. (Reproduced with permission from Lotke PA, Lonner JH. Master Techniques in Orthopaedic Surgery: Knee Arthroplasty. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2003.)

the bone, wh ich predisposes one to periprosthetic fracture. Th e tim in g of surgical in terven tion in th ese patien ts is actually som ewhat con troversial, as m any surgeon s favor early interven tion in asymptom atic individuals with significant, progressive osteolysis to avoid future com plication s.

Stiffness/Arthrofibrosis Patients’ pre-operative range of m otion is th e best indicator of postoperative ran ge of m otion of th e kn ee, m ean in g that those with good m otion before surgery will h ave th e best m otion after surgery. However, in som e cases, ran ge of m otion followin g TKA does n ot reach optim al levels. Approxim ately 100 degrees of knee flexion is needed for activities of daily living, an d failure to reach this can have m any possible causes, including poor patient compliance with reh abilitation , excessive postoperative swellin g an d pain , or poorly im plan ted com pon en ts. CPM is used in th e postoperative period to en courage m otion , but in som e cases, patients do not reach their goals. If patients are less than 2 to 6 weeks from the tim e of surgery, m anipulation of th e kn ee un der a gen eral an esth esia can be don e in an

Th e m ost com m on type of in stability followin g TKA is in th e varus–valgus plane. Th is can occur from several different m echan ism s, som e of wh ich include incompetence of th e collateral ligam en ts, poorly m ade bon e cuts, failure to correct preoperative deform ity, or an inadequately sized polyethylen e com pon en t. In gen eral, th e m ajority of th ese problem s can be iden tified an d corrected in traoperatively. One m ust be careful to protect the collateral ligam ents wh ile m akin g th e bon e cuts to avoid in jury, an d th e surgeon m ust also carefully balan ce th e kn ee prior to im plan ting the components. This is particularly problem atic in th e valgus knee, which can be quite difficult to correct and balance with surgery, and when don e in completely will lead to laxity on the m edial side of the knee. Patients with varus– valgus instability will often present with a stiff-legged gait, wh ich is don e to avoid flexion of th e kn ee. Wh en th e kn ee is flexed at heel strike, in stability will cause a pain ful m edial or lateral thrust depen ding on th e direction of th e instability. In stability in th e an terior–posterior plan e is less com m on but can occur with both cruciate-retaining and cruciate-substitutin g devices. Th is can result from excess resection of bon e from th e posterior fem oral condyles, from usin g too sm all a fem oral com pon en t, or from placin g excess slope on th e proxim al tibial cut. If th is is don e with a cruciate-retain in g prosth esis, th e PCL will gradually atten uate an d will rupture in som e cases. Th is will lead to sign ifican t in stability of th e kn ee, with th e tibia slidin g posteriorly relative to th e fem ur. In a cruciate-substitutin g prosth esis, th e stability is provided by th e polyethylen e post, but wh en th e flexion space is too loose, th e fem ur can actually jump th e post an d dislocate with th e kn ee in deep flexion (Fig. 18.22).

Periprosthetic Fracture Periprosth etic fracture following TKA is seen in approxim ately 2% of patients, an d of these, supracondylar fem ur fractures are th e m ost com m on (Fig. 18.23). Th ey are generally secon dary to m in or traum a, an d risk factors in clude osteoporotic bon e, lim ited ran ge of m otion in flexion , an d n otch in g of th e distal fem ur. Lim ited ran ge of m otion is im portan t because wh en on e falls on to th e leg with a flexed knee, th e force is typically absorbed by increasing the flexion of the knee. However, if flexion is lim ited, the force is dissipated elsewh ere, wh ich in m ost cases is to th e distal fem ur. Notch ing occurs when the anterior fem oral shaft is cut wh ile preparin g th e fem ur an d is a risk factor for fracture (Fig. 18.24).

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Figure 18.23 Periprosthetic fracture of the distal femur after a

fall. (Reproduced with permission from Lotke PA, Lonner JH. Master Techniques in Orthopaedic Surgery: Knee Arthroplasty. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2003.)

Figure 18.22 Postoperative radiograph following revision total

knee arthroplasty where the femoral component has jumped the polyethylene post, leading to a knee dislocation.

Treatm en t of periprosth etic distal fem ur fractures depends on th e degree of displacem en t an d th e status of th e arthroplasty. If the fem oral compon ent is already loose, then revision should be undertaken in addition to treatm en t of th e fracture. When th e fem oral component is well fixed, th e fracture can be treated eith er operatively or n on operatively. Non displaced an d m in im ally displaced fractures are gen erally treated n on operatively, wh ich con sists of non –weigh t-bearin g in eith er a lon g leg cast or a brace for 6 to 8 weeks. Displaced fractures should be treated operatively, th e option s for wh ich m ost com m on ly in clude open reduction in tern al fixation (ORIF) or retrograde in tram edullary n ailin g. O RIF is typically accom plish ed with a plate-and-screw construct placed on the lateral fem ur and is frequently done with a locking plate, wh ich adds stability

Figure 18.24 Notching (arrow) of the anterior cortex of the distal femur after a total knee arthroplasty.


Figure 18.25 Open reduction internal fixation of a distal femoral periprosthetic fracture with a locking plate.

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Figure 18.27 Open reduction internal fixation following a

periprosthetic proximal tibia fracture. (Reproduced with permission from Lotke PA, Lonner JH. Master Techniques in Orthopaedic Surgery: Knee Arthroplasty. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2003.)

in patients with osteoporotic bone (Fig. 18.25). Nailing is also an option (Fig. 18.26), but this requires placing the device th rough an opening in th e fem oral compon ent, which is not present on all prosth etic designs. Therefore, one m ust first iden tify the implant th at was used and then determ ine wh eth er or n ot it is con ducive to retrograde n ailin g. Periprosthetic tibial fractures also occur, although they are m uch less com m on . In m any cases, these are tibial shaft fractures resulting from sign ifican t traum a (Fig. 18.27). Th e stan dard treatm en t for tibial sh aft fractures is in tram edullary nailin g, which cannot be done with a TKA in place. Th erefore, treatm en t is altered an d lim ited to eith er castin g or ORIF. Tibial fractures also occur in th e settin g of tibial component m alalignm ent, which place excess stress on th e un derlyin g bon e. In m ost cases, th ese are m in im ally displaced, and nonoperative treatm en t can be utilized. However, in m any cases, tibial compon ent revision is needed.

Figure 18.26 Retrograde intramedullary nailing of a periprosthetic distal femur fracture. (Reproduced with permission from Lotke PA, Lonner JH. Master Techniques in Orthopaedic Surgery: Knee Arthroplasty. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2003.)

SUMMARY OA of th e kn ee is a sign ifican t problem th at is experien ced by a large proportion of th e agin g population . Th ere are m any options for con servative treatm ent of OA, but

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there is no way to reverse the progression of th e disease. Th erefore, surgical in terven tion becom es n ecessary in a large n um ber of in dividuals. Join t-sparin g operation s in clude arth roscopy, HTO, and UKA, all of wh ich h ave a role in certain patien t population s, but th e gold stan dard of surgical treatm ent contin ues to be TKA. TKA h as a wellestablish ed track record of providin g sym ptom atic relief to patien ts with OA, an d survivorsh ip con tin ues to im prove as better prosth eses are developed. Wh ile results are gen erally excellen t, it is im portan t to be aware th at sign ifican t complications can occur from what is a very invasive surgery. Th ese range from m in or function al deficits to fatal PE, so th e surgeon m ust always be aware of th eir possible developm ent, particularly in the early postoperative period.

RECOMMENDED READINGS Buckwalter JA, Saltzm an C, Brown T. The im pact of osteoarthritis: implications for research. Clin Orthop Relat Res. 2004;427(suppl): S6 –S15. Dixon MC, Brown RR, Parsch D, Scott RD. Modular fixed-bearin g total knee arthroplasty with retention of th e posterior cruciate ligam ent: a study of patien ts followed for a m in im um of fifteen years. J Bone Joint Surg Am. 2005;87(3):598 –603. Gonzalez MH, Mekhail AO. The failed total knee arthroplasty: evaluation an d etiology. J Am Acad Orthop Surg. 2004;12(6):436 –446. Naudie, DD, Am m een DJ, En gh GA, Rorabeck CH. Wear an d osteolysis around total knee arthroplasty. J Am Acad Orthop Surg. 2007;15(1):53 –64. Rand JA, Trousdale RT, Ilstrup DM, Harm sen WS. Factors affecting the durability of prim ary total knee prostheses. J Bone Joint Surg Am. 2003;85A(2):259 –265. Win dsor RE, Bon o JV. In fected total kn ee replacem en ts. J Am Acad Orthop Surg. 1994;2(1):44 –53.

19

Foot and Ankle Ben jam in D. Martin

Fran cis X. McGu igan

Th e tibia, fibula, an d th e 26 m ajor bon es of th e foot work in concert as essential components of the locom otion system . Con gen ital, acquired, an d traum atic con dition s are com m on in this region an d cause significant m orbidity and disability.

FUNCTIONAL ANATOMY Osteology Th e tibia is a trian gular lon g bon e th at expan ds proxim ally to form th e plateau at th e kn ee an d distally to form th e plafon d an d m edial m alleolus. Th e fibula is also trian gular an d is oriented sligh tly posterior and lateral to the tibia. Th e distal flare form s th e lateral m alleolus. Th ese two bon es articulate both proxim ally an d distally in arthrodial joints, allowing for slight translational and rotational m ovem ents. Distally, th e tibia an d fibula form th e an kle join t. Th e join t is secured th rough m ultiple ligam en tous con n ection s—th e in terosseous m em bran e, th e an terior in ferior tibiofibular ligam ent, and the posterior inferior tibiofibular ligam ent. Together, the tibia and fibula create th e m ortise of th e an kle, wh ich articulates with th e dom e of th e talus, allowing for dorsiflexion and plantarflexion. Th e foot is divided in to th ree separate region s—th e h in dfoot, m idfoot and forefoot, and three groups of bones: the tarsus, m etatarsus, an d ph alan ges. Th e h in dfoot in cludes the talus and calcaneus. The m idfoot is composed of th e navicular, cuboid, and the th ree cuneiform s. Th e forefoot region in corporates th e m etatarsals an d th e ph alan ges. Th e an atomy of th e talus is critical to un derstan din g th e hin dfoot. More than 60% of the talus is covered with hyaline cartilage. It consists of a head, neck, and body and has no m uscle or tendon attach m en ts. Stability is depen den t on bon e articulation s, join t capsules, an d ligam en ts. Th e body of th e talus h as a un ique trapezoidal sh ape, bein g wider an teriorly. Th is provides extra stability to th e an kle m ortise in

dorsiflexion . Th e m edial an d lateral con cave aspects of th e body articulate with th e respective m alleoli. Posteriorly, a sulcus is form ed between two tubercles to accom m odate the flexor hallucis lon gus (FHL). The os trigonum is an accessory bone seen in 50% of people that is attached to the posterolateral process of th e talus an d is usually bilateral. Th e in ferior aspect of the talus h as th e an terior, m iddle, an d posterior facets th at articulate with th e calcan eus to form the subtalar joint. The talar neck is oriented m edially an d in a plan tar direction an d creates th e roof of th e sin us tarsi. The n eck is the m ost at risk for fracture. The talar h ead articulates with the n avicular an d an terior process of the calcaneus. The calcaneonavicular ligam ent, or sprin g ligam en t, acts as a slin g to support th e talar h ead. Because m ost of the talus is covered with cartilage, there is lim ited area for th e blood supply to en ter. Th ree m ain arteries—th e posterior tibial, th e an terior tibial, an d th e perforatin g peroneal arteries—and their branches provide th e blood supply. Th e artery of th e tarsal can al, a bran ch of th e posterior tibial artery, an d th e artery of th e tarsal sin us, a bran ch of th e perforatin g peron eal artery, create an an astom otic slin g un der th e talar n eck (Fig. 19.1). Th e artery of the tarsal canal supplies the m edial half to two-thirds of the talar body, wh ereas th e sin us tarsi artery supplies th e lateral 25%. A fracture of th e talar neck can result in disruption of blood flow an d avascular n ecrosis of th e body. Th e calcan eus, or os calcis, tran sm its body weigh t to the ground and serves as a lever arm for the Achilles tendon . Th e an terior, m iddle, an d posterior facets articulate with th e correspon din g facets of the talus, with the posterior facet being the largest and m ost important. The m iddle facet overlies th e susten taculum tali, un der wh ich th e FHL ten don run s an d is often con fluen t with th e an terior facet. The sustentaculum tali also serves as the in sertion site of th e sprin g ligam en t an d th e tibiocalcan eal part of th e deltoid ligam en t. Th e lateral wall of th e calcan eus con tain s th e troch lear process, wh ich form s a groove for th e peron eus lon gus ten don . Distally, th e calcan eus articulates with th e

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Figure 19.2 The wedge shape of the three cuneiforms creates

the transverse arch of the foot, often compared to a Roman arch. (Reproduced with permission from Johnson D, Pedowitz RA. Practical Orthopaedic Sports Medicine and Arthroscopy. Philadelphia, PA: Lippincott Williams & Wilkins, 2007.)

Figure 19.1 The blood supply to the talus is primarily from an

anastomotic sling that originates from the artery of the tarsal sinus (A) laterally and the artery of the tarsal canal (B) medially. Additional blood vessels enter dorsally through the neck and medial body (C). (Reproduced with permission from Rockwood CA, Green DP, Bucholz RW. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

cuboid via a saddle joint. The cortical bone of the calcaneus is weak in th e cen tral body an d is susceptible to compression fracture. The m idfoot consists of th e navicular, cuboid, and th ree cuneiform bon es. The navicular serves as the keystone for the m edial longitudin al arch of the foot, articulatin g with the talus proxim ally and the cuneiform s distally. The posterior tibial tendon inserts on the m edial side of the navicular. An accessory n avicular, or os tibiale externum , is present in 10% of people. Th e cuboid form s th e lateral colum n through an articulation with the calcaneus proxim ally an d the fourth and fifth m etatarsals distally. A groove on the un dersurface of th e cuboid accom m odates th e peron eus lon gus ten don . Th e cun eiform s are trapezoidal in sh ape, taperin g plan tarly, con tributin g to th e form ation of th e tran sverse arch of th e foot (Fig. 19.2). Distally, th e cun eiform s articulate with th e first, secon d, an d th ird m etatarsals. Th e second cun eiform is shorter th an the others, allowing for the secon d m etatarsal to be recessed proxim ally (Fig. 19.3), providin g added stability to th e secon d tarsom etatarsal join t. The forefoot is composed of the five m etatarsals and ph alan ges, wh ich articulate to form th e m etatarsoph alan geal (MTP) join ts. Norm ally, th e first m etatarsal is th e sh ortest and widest an d bears one-third of the body weight. Th e plan tar surface of th e h ead of th e first m etatarsal articu-

lates with two sesam oid bon es that are encased by the flexor h allucis brevis (FHB) ten don . Th ese sesam oids provide a m echanical advantage by increasing the level arm for flexion, m uch like the patella for knee extension. Th e second m etatarsal is usually the longest and is recessed proxim ally between th e cun eiform s. Mobility of th e secon d m etatarsal is sacrificed for th is extra stability. The third, fourth, and fifth m etatarsals are successively sh orter, creatin g a curved appearance of the foot. The fifth m etatarsal has a prom in en ce at its base for in sertion of th e peron eus brevis tendon . Th e lesser four m etatarsals bear two-th irds of th e body weigh t equally. Th e ph alan ges of th e foot are sim ilar to th ose in th e h an d. Th e proxim al aspect of th e proxim al ph alanges is con cave to allow articulation with the convex head of th e m etatarsals. The distal ends h ave m ore of a trochlear shape that articulates with the correspon ding m iddle ph alanx. Each distal ph alan x term in ates in a tuft of bon e to serve as an anchor for the toe pad.

Ankle Joint Th e m ortise form ed by th e tibia an d fibula is dyn am ic but stable due th e bon e an atomy, thick posterior capsule, and ligam entous structures. As the foot dorsiflexes, th e fibula m oves proxim ally, posteriorly, and externally and rotates to provide room for th e trapezoid-sh aped talus, wh ich is wider an teriorly. Th e axis of th e an kle join t is n ot perpen dicular to th e m alleoli, such th at th e foot extern ally rotates 15 degrees with dorsiflexion an d internally rotates 15 degrees with plan tarflexion . Th e m edial deltoid complex an d th e lateral ligam en ts provide added stability. Th e deltoid is fan -sh aped ligam en t with deep and superficial components (Fig. 19.4). Th e superficial compon en ts in clude th e posterior tibiotalar, tibiocalcaneal, and the tibion avicular ligam ents. The an terior tibiotalar ligam ent form s th e deep component an d is importan t to m aintaining the m edial joint space. The lateral complex consists of the posterior talofibular ligam en t (PTFL), th e calcaneofibular ligam ent (CFL), and the

Chapter 19: Foot and Ankle

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Ca lca ne a l tube ros ity (pos te rior s urfa ce )

Groove for fle xor ha llucis longus

Ca lc a n e u s La te ra l tube rcle

Me dia l tube rcle

For tra ns ve rs e tibiofibula r liga me nt

For tibia

For fibula r ma lle olus

For me dia l ma lle olus

Exte ns or digitorum bre vis

Ta lu s

Cu b o id Groove for fibula ris (pe rone us ) longus

Tube ros ity Na vic u la r

Tube ros ity

3

Fibula ris (pe rone us ) bre vis Fibula ris (pe rone us ) te rtius

2

Th re e c u n e ifo rm s

1

5 4

3

2

Five m e ta ta rs a ls

1

P h a la n g e s Exte ns or ha llucis bre vis

Figure 19.3 The second metatarsal is recessed between the medial and lateral cuneiform, adding to the stability of the foot. (Adapted from Hoppenfeld S, DeBoer P. Surgical Exposures in Orthopaedics: The Anatomic Approach. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2003.)

Exte ns or e xpa ns ion

Me dia n ba nd La te ra l ba nds

Do rs a l Vie w

an terior talofibular ligam ent (ATFL) (Fig. 19.5). The ATFL, run n ing from the anteroin ferior aspect of the fibula to th e neck of the talus, is the prim ary restrain t against anteriorly directed forces wh en th e an kle is in th e n eutral position an d also resists inversion in the plantarflexed foot. The CFL, which extends from the tip of the fibula to the lateral tubercle of th e calcan eus, preven ts varus talar tilt wh en

the ankle is in neutral or dorsiflexed position. The PTFL runs from the posterior aspect of the distal fibula to the lateral tubercle of th e talus. A tear in on e or m ore of th ese lateral ligam en ts results in an an kle sprain , wh ich is com m on after an in version or plan tarflexion in jury. Th e ATFL is th e m ost vuln erable an d com m on ly in jured. Th e n orm al an gle between th e CFL an d ATFL averages 105 degrees in

Deep anterior talotibial

Superficial talotibial

Figure 19.4 The medial deltoid ligament

complex is comprised of superficial (A) and deep (B) components. (Reproduced with permission from Rockwood CA, Green DP, Bucholz RW. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Exte ns or ha llucis longus

A

Calcaneotibial

B Deep posterior talotibial

Naviculotibial Superficial deltoid ligament

Deep deltoid ligament

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Subtalar Joint

Anterior tibiofibular ligament Anterior talofibular ligament

Posterior talofibular ligament Calcaneofibular ligament

Figure 19.5 The posterior talofibular ligament (PTFL), the cal-

caneofibular ligament (CFL), and the anterior talofibular ligament (ATFL) together form the lateral collateral structures of the ankle. The anterior tibiofibular ligament is part of the syndesmosis. (Reproduced with permission from Rockwood CA, Green DP, Bucholz RW. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

the sagittal plane. It is thought that in dividuals with greater an gles m ay be m ore susceptible to in jury. The syn desm osis provides stability to the distal tibiofibular articulation an d th us th e m ortise (Fig. 19.6). Th e an terior tibiofibular, th e posterior tibiofibular, in ferior transverse ligam ent, and the interosseous m em brane form the syndesm osis. Injury to these structures can result from hyperdorsiflexion and external rotation. Th ese are often referred to as “h igh ’’ an kle sprain s an d are associated with a slower fun ctional recovery than injury to the lateral ligam en ts.

Th e subtalar join t is essen tially a h in ge join t between th e talus an d calcan eus, creatin g an axis for in version an d eversion . Function ally, this translates into the ability to am bulate on uneven ground. The axis of the joint averages 23 degrees m edially from th e lon gitudin al axis of th e foot an d 42 degrees from th e h orizon tal plan e an d usually h as approxim ately 10 degrees to 60 degrees of m otion. The range of m otion varies depending on an atomy. For example, a cavus (high-arched) foot has m uch less m otion than a plan ovalgus (flat) foot. Ligam entous resistance to inversion is provided by the inferior extensor retinaculum when the foot is in neutral and dorsiflexion. Th e CFL, joint capsule, interosseous talocalcan eal ligam en t, an d th e ligam en t of th e tarsal can al also con tribute to stability.

Transverse Tarsal Joint Th e tran sverse tarsal join t, or Ch opart join t, is th e sum of the saddle-shaped calcan eocuboid an d concave talon avicular join ts. Th e orien tation of th ese join ts ch an ges with th e position of th e calcan eus such th at wh en th e calcan eus is in valgus, the joints are parallel and m obile. Durin g heel strike, th is allows th e dissipation of forces. Wh en the calcaneus is in varus, the joints diverge, resulting in a rigid m idfoot, which is essen tial to effective push -off.

Midfoot Joints Th e m idfoot join ts are stabilized by m ultiple ligam en ts an d by the intrinsic bony architecture of th e wedge-shaped cun eiform bon es. Th is section of the foot is prim arily a

IOL PITFL

AITFL

ITL

Anterior

AITFL

Posterior AITFL

Figure 19.6 The syndesmosis is composed of the anterior inferior tibiofibular (AITFL), the posterior

inferior tibiofibular (PITFL), inferior transverse ligament (ITL), and the interosseous membrane (IOM). (Reproduced with permission from Rockwood CA, Green DP, Bucholz RW. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

PITFL Lateral


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stable segm ent designed to handle the stresses of the stan ce ph ase of gait. Little m otion actually occurs th rough th ese articulation s. The Chopart ligam ent, long plantar ligam ent, an d short plantar ligam ent provide stability to the join ts an d to the longitudin al arch of the foot.

through the proxim al interphalangeal (PIP) joints, whereas both th e proxim al an d distal in terph alan geal (DIP) join ts h ave little extension .

Tarsometatarsal Joints

Th e extrin sic m uscles of th e foot are separated in to four fascial compartm en ts in th e leg—th e superficial an d deep posterior compartm en ts, th e lateral com partm en t, an d th e anterior compartm ent. The superficial posterior compartm ent includes th e gastrocnem ius, plantaris, an d the soleus m uscles. The gastrocnem ius originates from the m edial and lateral fem oral condyles an d joins the soleus m uscle, which origin ates from th e posterior tibia an d fibula, to form th e Ach illes ten don . Th e Ach illes ten don , also referred to as th e tendo calcaneus, rotates 90 degrees as it in serts on to th e posterosuperior tuberosity of th e calcan eus. Th is is th e largest and strongest tendon in the body. The plantaris originates from the lateral fem oral condyle and is m ostly tendinous alon g its len gth as it courses between th e soleus an d the gastrocnem ius to insert just m edial to the Achilles tendon on th e calcan eus. Th e plan taris can be used as a ten don graft but is absen t in approxim ately 7% of people. Th ese th ree m uscles, often referred to as th e triceps surae, are in n ervated by th e tibial n erve an d fun ction as th e prim ary plan tarflexors of th e an kle. Th ey also assist in in version of th e h in dfoot. Th e tibialis posterior, th e flexor digitorum lon gus (FDL), and the FHL are th e three m uscles of th e deep posterior com partm en t an d serve as in verters of th e foot an d secon dary plan tarflexors. Th ese m uscles origin ate from th e posterior tibia an d in terosseous m em bran e an d pass togeth er as ten don s beh in d th e m edial m alleolus in th e tarsal can al un der th e flexor retin aculum alon g with th e posterior tibial artery and nerve (Fig. 19.7). Th e tibialis posterior inserts on th e navicular, m edial and m iddle cun eiform s, and th e bases of th e secon d, th ird, an d fourth m etatarsals. Its

Dorsal, plan tar, an d in terosseous ligam en ts stabilize th e tarsom etatarsal join ts, or th e join t of Lisfran c. Th e in terosseous ligam en ts are tran sverse con n ection s between the adjacent m etatarsal bases, except between the first and secon d m etatarsals. Joint stability for that articulation is instead conferred via the oblique ligam ent, or Lisfranc ligam ent, that spans from the m edial cun eiform bone to the secon d m etatarsal. The first tarsom etatarsal join t is th e only on e with sign ifican t m otion because of th e lack of con n ection to th e neighboring m etatarsal. Significant dorsiflexion, plantarflexion , and rotation all occur during the gait cycle.

Metatarsophalangeal Joints Th e MTP join ts of th e lesser toes are stabilized by th e bony sh ape, th e fibrocartilagin ous plan tar plates origin ating from th e m etatarsal heads an d inserting on the bases of th e proxim al ph alan ges, th e deep tran sverse m etatarsal ligam ent, and the collateral ligam ents. Atten uation of th ese structures can result in dorsal subluxation and dislocation. Th e MTP join t of th e h allux h as a ran ge of m otion of 70 degrees allowin g for th e toe-off ph ase of th e gait cycle.

Interphalangeal Joints Th e in terph alan geal join ts are gin glym us join ts with cam sh aped condyles an alogous to th ose in the hand, with sim ilar anatomy and ligam en tous support. More flexion occurs

Extrinsic Muscles of the Foot

Saphenous nerve Flexor digitorum longus Saphenous vein

Tibials posterior Posterior tibial artery

Tibials anterior

Tibial nerve

Flexor hallucis longus

Figure 19.7 Anatomy of the medial neurovascular

structures as they course behind the medial malleolus. (Reproduced with permission from Rockwood CA, Green DP, Bucholz RW. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

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prim ary fun ction is in version of th e foot, but it also con tributes to th e support of th e lon gitudin al arch . Th e FDL travels beh in d th e m edial m alleolus with th e tibialis posterior superficial to the deltoid ligam ent an d into th e plantar aspect of th e foot just plan tar to th e FHL. After join in g with the quadratus plantae, it divides into four slips and inserts on to th e base of th e distal ph alan x of th e lesser toes. Th e FDL flexes th e MTP, PIP, an d DIP join ts of th e lesser toes an d serves as a weak an kle plan tarflexor. Th e FHL is th e m ost lateral m uscle of th e deep posterior compartm en t an d courses between the posterior talar processes, under the sustentaculum tali, an d th rough th e secon d layer of plan tar aspect of th e foot to in sert on th e distal ph alan x of th e great toe. It is th e prim ary flexor of th e h allux an d a weak an kle plan tarflexor. Th e tibial n erve in n ervates th ese th ree m uscles. The lateral compartm ent contain s the peroneus lon gus an d peron eus brevis m uscles, wh ich are in n ervated by th e superficial peroneal nerve. The peroneus longus is m ore superficial and is posterolateral to the peroneus brevis behind the lateral m alleolus. The peroneus lon gus origin ates from the upper two-th irds of the lateral fibula and interm uscular septum an d in serts on th e plan tar base of the first m etatarsal and m edial cuneiform after traveling ben eath th e cuboid. Th e m uscle plan tarflexes th e first ray an d con tributes som e an kle plan tarflexion an d foot abduction . Th e peron eus brevis origin ates from th e distal twothirds of the interm uscular septum and inserts onto the base of th e fifth m etatarsal an d serves as th e prim ary evertor of th e foot. In som e in dividuals, a th ird m uscle, th e peron eus tertius, parallels th e peron eus brevis an d in serts on th e dorsal base of th e m etatarsal. Th e ten don s are h eld within the peroneal groove as th ey pass posteriorly and aroun d th e lateral m alleolus by th e superior an d in ferior peron eal retin aculum . Th e CFL lies deep to both ten don s at th e tip of th e lateral m alleolus. The tibialis anterior, the extensor h allucis longus (EHL), an d th e exten sor digitorum lon gus (EDL) form th e an terior compartm en t of the leg and are innervated by the deep peron eal n erve. As a group, th ese m uscles dorsiflex th e foot an d an kle. Th e tibialis an terior origin ates from th e lateral tibial con dyle an d th e in terosseous m em bran e an d in serts on to th e m edial border of th e m edial cun eiform an d base of th e first m etatarsal. In addition to dorsiflexion of th e an kle, it in verts th e subtalar join t an d supports th e lon gitudin al arch of th e foot. Th e tibialis an terior m uscle is the antagonist of the peron eus longus m uscle. The EHL, the prim ary extensor of th e hallux, arises from the m iddle two-th irds of th e an terior fibula an d in terosseous m em bran e an d in serts on to th e distal ph alan x of th e h allux. Th e EHL weakly dorsiflexes the an kle and inverts the foot. The EHL crosses from lateral to m edial over the dorsalis pedis artery an d deep peron eal n erve just proxim al to th e an kle join t. Th e dorsalis pedis artery an d deep peron eal n erve are bordered by th e EHL m edially an d th e EDL laterally at

th e level of th e an kle join t. Th e EDL origin ates from th e lateral tibial con dyle, interosseous m em brane, and th e interm uscular septum . Com bin ed with fibers from th e lum bricals an d in terossei m uscles, it form s a broad apon eurosis at the proxim al phalanx of each lesser toe. The aponeurosis splits at th e distal en d of the proxim al ph alanx to form a cen tral an d two lateral slips. Th e cen tral slip in serts on to th e m iddle ph alan x, an d th e lateral slips form th e exten sor h ood over the DIP join t. Th us th e EDL can exten d th e MTP join ts as well as th e PIP an d DIP join ts. However, PIP an d DIP exten sion s can occur on ly wh en th e MTP join t is in n eutral or sligh t flexion.

Intrinsic Muscles of the Foot Wh ile th ere are four layers of plan tar m uscles in th e foot, there is only one dorsal m uscle. The extensor digitorum brevis (EDB), in n ervated by th e lateral bran ch of th e deep peron eal n erve, origin ates from th e sin us tarsi an d superolateral calcaneus and form s four tendons. The th ree lateral ten don s join th e lateral aspect of th e ten don s of th e EDL. Th e m ost m edial part of th e EDB is often distin ct an d referred to as the extensor hallucis brevis. Th is tendon inserts on th e base of th e proxim al ph alan x of th e h allux. Th e m edial an d lateral plan tar n erves in n ervate all th e plan tar m uscles. Th e superficial layer of th e plan tar m uscles con sists of three m uscles that are deep to the plantar fascia, origin ate from th e calcan eal tuberosity, an d in sert in to th e toes. Th e abductor h allucis is th e m ost m edial. Its ten don m erges with the m edial slip of th e FHB ten don to insert on th e base of th e proxim al ph alan x of th e h allux. Th e flexor digitorum brevis (FDB) form s four tendons, one for each of th e lesser toes. Prior to in sertion on th e m iddle ph alan x of th e respective toe, each divides in to a m edial an d lateral slip through which pass the FDL tendon. This is analogous to the anatomy of th e flexor tendons of the upper extrem ity. Th e abductor digiti m in im i (ADM), th e m ost lateral m uscle, crosses under the fifth m etatarsal to insert on the lateral side of the proxim al phalanx of the sm all toe. Th e secon d layer con tain s th e quadratus plan tae, lum brical m uscles, an d th e ten don s of th e FHL an d FDL. Th e quadratus plan tae origin ates from th e calcan eal tuberosity as a m edial an d lateral head and ultim ately form s tendons that join the FDL ten dons to the lesser toes. It assists in toe flexion an d is also referred to as th e flexor digitorum accessorius. Th e anatomy of the quadratus varies. Th e m uscle m ay be congenitally absent. There are four lum bricals, each origin atin g from th e m edial side of a FDL ten don an d in sertin g on th e dorsal exten sor apon eurosis of the proxim al ph alan ges. Th e lum bricals flex th e MTP join ts an d exten d the PIP join ts. Th e th ird layer con tain s th e FHB, th e adductor h allucis, an d the flexor digiti m inim i. The FHB originates from th e posterior tibial ten don an d divides in to two h eads. Each


head contains a sesam oid under the first m etatarsal h ead an d in serts on the base of the first m etatarsal. The m edial head joins the abductor h allucis ten don and th e lateral join s th e adductor h allucis ten don . Th e adductor h allucis is form ed from oblique and tran sverse heads. The oblique head originates from the base of the cuboid and secon d, third, and forth m etatarsals. The transverse head origin ates from the plantar plates an d transverse m etatarsal ligam ents of th e th ird, fourth , an d fifth m etatarsals. Th e adductor hallucis provides reinforcem en t to th e transverse m etatarsal ligam ents. In a bunion (hallux valgus), con tracture of the adductor m uscle is part of the deform ity. The flexor digiti m inim i originates from the fifth m etatarsal, an d its tendon com bin es with the ADM to insert on the lateral side of th e proxim al ph alan x of th e fifth toe. Togeth er, th ey flex an d abduct th e fifth digit. Th e fourth an d deepest layer con tain s th e in terossei m uscles and th e tendons of the peroneus longus, posterior tibialis, an d an terior tibialis. Th ere are four bipen n ate dorsal an d th ree un ipen n ate plan tar in terossei m uscles. Th e dorsal group abducts th e secon d, th ird, an d fourth toes relative to the second m etatarsal, whereas the plantar group adducts the third, fourth, and fifth toes. Along with th e lum bricals, th e in terossei assist in flexion of the MTP joints an d exten sion of the PIP and DIP join ts via the extensor aponeurosis.

Neurovascular Structures Five m ajor n erve bran ch es an d th ree arteries supply th e foot and ankle. Most of the sensory and m otor inn ervation to the foot and ankle com e from the two portions of the sciatic nerve, the com m on peroneal (L4 –S2) an d tibial nerves (L4 –S3). Th e com m on peron eal n erve divides in the anterior compartm ent into the deep and superficial peron eal n erves after crossin g aroun d th e n eck of th e fibula. At th is point, the nerve is m ost susceptible to injury, especially compression n europathy. The deep peroneal n erve inn ervates the anterior compartm ent m uscles and travels with th e an terior tibial artery across th e an kle un der th e exten sor retin aculum . Ultim ately, it in n ervates som e of th e intrinsic m uscles of the foot and provides sen sation in the first dorsal webspace. Th e superficial peron eal nerve inn ervates th e lateral compartm ent m uscles and provides sen sation to th e dorsum of th e foot and toes. This n erve is at risk durin g exposure of the fibula approxim ately 10 to 15 cm above the lateral m alleolus. It becom es subcutaneous at that level passing from the lateral in to th e an terior compartm en t of th e leg. Care sh ould be taken wh en exposin g fractures of th e fibula above th e lateral m alleolus. Th e sural n erve is an oth er bran ch of th e com m on peron eal n erve th at provides sen sation to th e lateral side of th e foot. It travels separately from th e superficial an d deep peron eal n erves run n in g posteriorly over th e gastrocsoleus com plex and even tually passin g m idway between

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the lateral m alleolus and Achilles tendon at the level of the ankle. Th e tibial n erve lies deep in th e posterior compartm en t of th e leg with th e posterior tibial artery an d con tin ues un dern eath th e flexor retin aculum beh in d th e m edial m alleolus. Un der th e flexor retin aculum , th e m edial calcan eal n erves branch from th e tibial n erve, perforate th e retinaculum , an d provide sen sation to th e h eel an d m edial sole of th e foot. After exitin g th e tarsal tun n el, th e tibial n erve divides in to th e m edial an d lateral plan tar n erves th at in n ervate th e intrin sic m uscles an d th e skin of th e bottom of the foot. Th e saph en ous n erve, a term in al bran ch of th e fem oral n erve (L2 –L4), which provides sensation to th e m edial aspect of th e leg an d foot, is th e on ly in n ervation of th e foot that is not derived from the sciatic nerve. The nerve travels posterior to th e greater saph en ous vein . Th e an terior tibial, posterior tibial, an d peron eal arteries supply th e lower leg. Th e anterior and posterior tibial arteries are th e term in al bran ch es of th e popliteal artery. Th e an terior tibial artery en ters th e an terior compartm en t th rough the interosseous m em bran e below the proxim al tibiofibular join t. It travels alon g th e in terosseous m em bran e m edial to th e deep peron eal n erve. Before passin g un der th e superior an d in ferior exten sor retinaculum , it gives off the an terior m edial an d lateral m alleolar bran ch es to supply the m alleoli. Below the retinaculum , it becom es known as the dorsalis pedis artery and is superficial enough to be palpable as an arterial pulse. Th e dorsalis pedis artery sen ds a lateral bran ch to th e sin us tarsi, a deep bran ch kn own as the arcuate artery that con tributes to the deep arterial arch, an d a term in al bran ch th at form s th e first dorsal m etatarsal artery. Th e posterior tibial artery gives off a lateral bran ch h igh in th e calf, called th e peroneal artery. Th e peroneal artery travels posterior to th e in terosseous m em bran e deep to th e FHL. It term in ates at th e distal tibiofibular join t, form in g an anastom osis with the lateral m alleolar artery of th e an terior tibial artery. Th e posterior tibial artery run s deep to th e gastrocn em ius an d soleus m uscles, providin g a blood supply to the posterior compartm ent. After passin g un der th e flexor retin aculum with th e tibial n erve, th e posterior tibial artery term in ates as th e m edial an d lateral plan tar arteries.

Gait Analysis Th e gait cycle con sists of even ts occurrin g from h eel strike to the next h eel strike of the sam e foot. It is divided into th e stan ce an d swing phases. The stance phase m akes up 62% of th e cycle an d th e swin g ph ase m akes up th e rem ain in g 38%. Th e stan ce ph ase is furth er separated in to th ree segm ents: the initial double-lim b support (loading response), th e sin gle-lim b stan ce, an d th e term in al double-lim b support (preswin g). Sim ilarly, th e swin g ph ase is separated into initial swing, m idswing, and term inal swing phases.

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Although m ost lim b m otion takes place in th e sagittal plan e, coron al an d tran sverse m otion s do occur. With foot strike, th e transverse tarsal joint is unlocked to allow axial forces to dissipate. Toward the en d of th e stance phase, the subtalar joint inverts, locking th e transverse tarsal join t and allowin g effective push -off from th e forefoot. Th e five prerequisites of n orm al gait are appropriate foot preposition in g for in itial con tact, stan ce ph ase stability, swin g ph ase clearance, adequate step length, and m axim ization of en ergy con servation .

EVALUATION OF FOOT AND ANKLE PROBLEMS History A pertinent history guides th e physical exam ination an d is th e basis of a prelim in ary differen tial diagn osis. A welldirected question n aire provides an accurate an d com plete docum en tation of patien t’s complain t, m edical h istory, an d review of system s. Th e m ech an ism of in jury; th e location , duration , an d ch aracter of th e pain ; th e relation sh ip of th e pain to activities an d th e effectiven ess of alleviatin g factors such as over-th e-coun ter m edication s an d ice h elp to n arrow th e likely cause of th e patien t’s path ology. Oth er symptom s to note include tim ing and duration of swelling, in stability, an d ch an ges in an kle an d foot align m en t. Existin g system ic disorders—in cludin g in flam m atory, in fectious, n eoplastic, m etabolic, an d con gen ital con dition s – sh ould be elicited, with a specific emph asis on gout an d diabetes m ellitus. A m edical an d surgical h istory, with em ph asis on th e appen dicular an d extrem ity m usculoskeletal system s is h elpful in creating a diagn ostic an d th erapeutic plan of treatm en t. Activity level, occupation , level of education , an d socioecon om ic status assist in determ in in g the impairm ent imposed by th e patient’s condition and any obstacles to patien t complian ce with treatm en t. Fam ily h istory is h elpful because m any of th e foot an d an kle disorders arise from a h ereditary predisposition , in cludin g con gen ital abn orm alities an d in flam m atory m etabolic disorders.

Physical Examination A sound foot an d an kle exam in ation should follow th e prin ciples of any orth opaedic exam in ation : in spection , palpation , ran ge of m otion , m an ipulation , an d n eurovascular exam in ation. A fun dam ental un derstanding of the an atomy discussed earlier is critical in perform in g a com plete focused physical. Th e exam in ation begin s as th e patien t walks in to th e exam in ation room , providin g an opportun ity to evaluate gait pattern s. It is importan t to rem ove sh oes and socks for complete evaluation. Extrem ity alignm en t sh ould be assessed from th e fron t an d back with th e subject stan ding an d sittin g. Gait should again be observed

with out sh oes an d supports. Th e sole of th e patien t’s sh oes are inspected, and abnorm al sh oe wear is noted. Lateral sole wear is associated with a cavovarus foot an d m edial wear with a plan ovalgus foot. Special atten tion is given to th e h in dfoot align m en t an d its relation to th e forefoot. Th e longitudinal arch is noted both with and without weightbearin g. Callous form ation over bony prom in en ces th at in dicate areas of excessive pressure sh ould be evaluated. Th e con dition of th e soft tissues is critical, especially in th e setting of traum a and in patients with diabetes. Palpation will depen d on wh ere th e patien t is h avin g sym ptom s an d th e un derlyin g path ology. More details will be discussed in th e following sections; h owever, a brief discussion on the exam ination of the m ajor joints of the foot and ankle follows. Th e an kle join t sh ould be ch ecked for th e presen ce of an effusion versus local tissue swelling. Palpating th e ankle join t eith er m edial to th e tibialis an terior ten don or lateral to th e EDL ten don best assesses th is. Th e n orm al ran ge of m otion for th e an kle is 20 degrees of dorsiflexion an d 50 degrees of plan tarflexion . Loss of an kle dorsiflexion , an equinus contracture, can be associated with heel cord tightness, posterior capsule contracture, or anterior bony impingem ent. Contracture of the heel cord occurs from sh ortenin g of eith er on e or both of the gastrocnem ius and soleus m usculotendin ous units. To distin guish the cause of th e con tracture, an kle dorsiflexion is tested with th e kn ee exten ded an d again with th e kn ee flexed to 90 degrees. By flexing th e kn ee to 90 degrees, th e gastrocn em ius m uscle, wh ich crosses th e kn ee, is relaxed. Th e gastrocn em ius is con tracted on ly wh en th ere is n o restriction to dorsiflexion in this position . If restriction is present in both positions, both m usculotendinous units are contracted. The lateral side of th e ankle is a com m on site of pathology because an kle sprain s are so com m on . Ten dern ess over th e ATFL, with or with out pain alon g th e CFL, is ch aracteristic of a lateral an kle sprain . Stability is tested with th e an terior drawer an d in version stress tests. Th e an terior drawer test exam in es th e com peten cy of th e ATFL. With th e tibia stabilized with on e h an d, th e exam in er applies an an teriorly directed force by pullin g an teriorly, with th e secon d h an d graspin g th e posterior h eel (Fig 19.8). In version stress tests of th e an kle sh ould be applied in both dorsiflexion an d plan tarflexion to assess th e laxity of th e CFL an d ATFL, respectively. Th e subtalar join t typically allows for m ore in version th an eversion by a factor of th ree to on e. Typically, in version is approxim ately 20 degrees and eversion is 7 degrees; h owever, this depen ds on th e patien t’s an atom y. For exam ple, a cavovarus foot will h ave a decreased ran ge of m otion , wh ereas a plan ovalgus foot will h ave an in creased ran ge of m otion.

Imaging Plain radiograph s of th e foot an d an kle are th e best in itial form s of im aging; however, arthrography, computed


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an d articular cartilage in juries. It is also useful to evaluate avascular necrosis an d osteomyelitis.

TRAUMATIC INJURIES TO THE FOOT AND ANKLE Pilon Fractures

Figure 19.8 The anterior draw test is used to examine the competency of the ATFL. An anterior force is applied to the posterior heel with the ankle in 10 degrees of plantarflexion while the tibia is stabilized. (Reproduced with permission from Johnson D, Pedowitz RA. Practical Orthopaedic Sports Medicine and Arthroscopy. Philadelphia, PA: Lippincott Williams & Wilkins, 2007.)

tom ography (CT) scan s, an d m agn etic reson an ce im agin g (MRI) scan can be useful in certain situations. When possible, radiograph s sh ould be taken wh ile weigh t-bearin g an d include an anteroposterior (AP), lateral and oblique views for the foot and AP, lateral, an d m ortise views for th e ankle. For th e AP view of th e foot, th e beam is directed 15 degrees from the vertical toward the hindfoot, with the beam cen tered at th e level of th e talon avicular an d calcan eocuboid join ts. Th e AP view allows for assessm en t of th e forefoot an d m idfoot. The oblique view is used to evaluate the relationship of the lateral tarsom etatarsal join ts. It is obtained with th e kn ee flexed an d th e side of th e foot an gled at 30 degrees to th e surface of th e cassette with th e beam directed vertically. Additional im ages such as sesam oid views, the Harris axial h eel view, and Broden view are available to evaluate specific path ology. Th ese variation s will be discussed later in sections dealing with specific foot and ankle con ditions. As m en tioned, a standard ankle series includes an AP, lateral, an d m ortise views. The AP radiograph allows evaluation of th e distal tibia an d fibula, th e talar dom e, an d th e integrity of th e syndesm osis. The m ortise view aids in assessing th e ankle joint spaces. It is obtained with th e ankle intern ally rotated 20 degrees to orient the joint axis parallel to th e radiograph ic beam . An kle stress views are h elpful in diagn osin g in stability pattern s. CT scan s are h elpful to detect occult bon e lesion s, evaluate intraarticular pathology like bony coalition s, an d assess fracture patterns in calcaneus injuries. Im ages of th e subtalar join t are taken perpen dicular to th e posterior facet of th e calcan eus. MRI is used to evaluate soft tissue path ology in cludin g tum ors, ligam en t an d ten don abn orm alities,

Pilon fractures are in juries of th e distal tibial articular surface or plafon d. Th ey are typically h igh -en ergy in juries an d are associated with significant soft tissue injury. The exten t of th e soft tissue in volvem en t varies, but it affects th e m anner in which these fractures are treated. Most often th ese fractures require open reduction an d in tern al fixation (ORIF) to restore the join t surface and provide the best possible outcom e. Th ese in juries accoun t for 10% of all lower extrem ity fractures.

Classification Pilon fractures h ave h istorically been classified accordin g to Rü edi an d Allgö wer (Fig. 19.9). Type I fractures are n on displaced. Type II fractures are displaced with m in im al com m inution, whereas type III fractures are displaced with sign ifican t com m in ution . The AO / O TA classification is m ore descriptive an d h as th ree m ain types. Type A fractures are n on articular. Type B fractures in volve part of th e articular surface, and type C fractures involve the entire articular surface. Th ese th ree types are furth er subclassified based on th e am oun t of com m in ution . Th e soft tissue en velope can be classified on th e basis of a scale of 0 to 3, accordin g to Tsch ern an d Goetzen . In creasin g grades are associated with m ore dam age to th e surroundin g soft tissue. Mechanism of Injury Pilon in juries result from axial loads, with or with out a rotation al compon en t, m ost com m on ly as a result of falls from a height or the impact of m otor veh icle crash es. The position of th e foot at th e tim e of im pact affects th e fracture location (Fig. 19.10). If th e foot is in dorsiflexion , th e anterior portion of the tibia is fractured, wh ereas in plantarflexion , th e posterior tibia is fractured because of th e impact of the talar dom e. With th e ankle in neutral at the tim e of impact, the m iddle portion of the distal tibia is m axim ally involved. Pilon fractures are distinguished from ankle fractures with intraarticular exten sion by their m echanism and degree of injury. Ankle fractures are typically rotation al in juries with th e m ain fracture lin es in volvin g th e lateral, m edial, an d posterior m alleoli (Table 19.1). Presentation Patien ts com m on ly presen t with sign ifican t pain an d swellin g about th e an kle and varyin g degrees of soft tissue dam age. Because of th e h igh -en ergy m ech an ism s associated with these injuries, m any patients m ay have sustain ed addition al orthopaedic or organ system in juries.

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Figure 19.9 The classification of

I

II

Physical Examination Th e exten t of soft tissue in jury is importan t as it directs treatm en t. An open in jury or an in jury th at results in vascular comprom ise, such as a fracture dislocation, is a surgical em ergen cy. If th e in jury is several h ours old, fracture blisters about th e lower extrem ity are often presen t. Th e full exten t of soft tissue in jury m ay n ot declare itself im m ediately, an d so serial exam in ation is warran ted. In addition to evaluatin g th e soft tissue status an d docum en tin g a th or-

III

distal tibia fractures according to Ruedi ¨ and Allgower. ¨ The type corresponds to the degree of articular comminution. (Reproduced with permission from Rockwood CA, Green DP, Bucholz RW. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

ough n eurovascular exam in ation , it is essen tial to perform a complete secondary survey on patients involved in any h igh-energy traum a, to avoid m issin g addition al life- or lim b-threaten ing injuries.

Imaging Stan dard an kle radiograph s are th e prim ary im agin g study. CT scan is helpful to delineate fracture pattern s and determ ine the am ount of com m inution for surgical plannin g.

TABLE 19.1

CHARACTERISTICS OF ROTATIONAL COMPARED WITH AXIALLY LOADING FRACTURES Rotation

Axial Load

Slow rate of load application Little energy released at failure (yield point) Predominant translational displacement of talus Little comminution Minimal soft tissue injury

Rapid rate of load application Large amount of energy released A component of proximal displacement of talus Comminuted articular surface and metaphysis Severe soft tissue injury

Reproduced with permission from Rockwood CA, Green DP, Bucholz RW. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.


Dorsiflexion

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ven t im m ediate surgical fixation of th e fracture; in th ese situation s, an external fixator span ning the joint provides temporary im m obilization an d defin itive fixation is often delayed for 10 days to 2 weeks. On ce th e soft tissue in jury h as subsided en ough to allow surgery, an ORIF usin g plates an d screws is perform ed. Most prin ciples of in traarticular fracture treatm en t apply to pilon fractures. Th e surgical goals are an atom ic reduction of th e join t surface an d rigid fixation to allow early range of m otion. Im m ediate weight-bearing is often delayed for up to 3 m onths followin g surgical reduction . Extern al fixation with fin e wires an d lim ited in tern al fixation can also serve as defin itive fixation .

Ankle Fractures Neutral

Plantarflexion

Figure 19.10 The area of the tibial plafond fracture depends

on the position of the foot at the moment of axial load. (Reproduced with permission from Rockwood CA, Green DP, Bucholz RW. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

If a temporizin g extern al fixator is plan n ed because of th e degree soft tissue in jury, it is best to wait to obtain th e CT scan un til after it h as been placed.

Treatment Gross m alalign m en t an d associated dislocation s sh ould be reduced im m ediately an d th e lim b im m obilized. Th is reduces th e patien t pain an d m in im izes addition al soft tissue traum a. Frequen tly, soft tissue swellin g and injury pre-

An kle fractures are am on g th e m ost com m on in juries treated by orthopaedic surgeons. These are often lowen ergy rotation al in juries th at occur in people of all ages, with th e h igh est in ciden ce in elderly wom en .

Classification Th ere are a n um ber of classification s system s used, but th e Weber an d Lauge –Hansen system s receive the m ost recogn ition. The Weber system is based on th e level of the fibula fracture: type Aare below the level of the syn desm osis, type B fractures are at the level of the syn desm osis, and type C fractures are above the level of th e syndesm osis (Fig. 19.11). Type C fractures are m ost likely to be associated with a sign ifican t syn desm otic in jury. Th e Lauge–Hansen classification system is based on th e m ech an ism of an kle fractures. Injuries to bon es and soft tissues structures are taken in to accoun t. Th e term in ology describes th e position of th e foot at th e m om en t of in jury an d th en th e direction of the deform ing force (Fig. 19.12). For instance, in a supin ation-external rotation (SER) injury, th e foot is in

C

B

A

Figure 19.11 The Weber classification of ankle fractures depends on the level of the fibula fracture in relation to the syndesmosis. (Reproduced with permission from Rockwood CA, Green DP, Bucholz RW. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

764

Orthopaedic Surgery: Principles of Diagnosis and Treatment Supinated foot

External rotation

Adduction

I

I Anterior tib–fib sprain

Talofibular sprain or avulsion of distal fibula

Transverse fibula or rupture of talofibular ligaments II

II Stable short oblique fracture of the distal fibula

Vertical medial malleolus with a transverse distal fibula and possible medial plafond impaction

III Similar to II with additional rupture of posterior tib–fib ligament or fracture of posterior margin Posterior malleolus or posterior tib– fib ligament

IV Unstable short oblique fracture of the distal fibula with a medial malleolus fracture or a deltoid ligament disruption

A

Medial malleolus or deltoid

Figure 19.12 The Lauge–Hansen classification system is commonly used for the description of ankle fractures. The system identifies the position of the foot at the time of injury as either supinated (A) or pronated (B) followed by the direction of forces acting on the ankle. (Reproduced with permission from Rockwood CA, Green DP, Bucholz RW. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)


765

Pronated foot

External rotation

Adduction

I

I Isolated medial malleolus or deltoid ligament rupture

Isolated medial malleolus or deltoid ligament rupture

Medial malleolus fracture or deltoid rupture

Medial malleolus or deltoid

II

II

Chaput's tubercle or anterior tib–fib ligament

Chaput's tubercle or anterior tib–fib

III

III Transverse or laterally comminuted fibula with medial injury. Anteriolateral tibial impaction is also possible

Medial injury with a high fibula fracture

IV Similar to stage III with a posterior malleolus or tib–fib ligament injury Posterior malleolus or posterior tib– fib ligament

B

Figure 19.12 (Continued )

766


a supin ated position an d an extern al rotation force is applied. Four types are described: supin ation -adduction , SER, pron ation -abduction , an d pron ation -extern al rotation . Each type is furth er subclassified on th e basis of th e degree of in volvem en t of differen t soft tissue an d bon e structures. Supination in juries are the m ost com m on and accoun t for approxim ately 75% of all an kle fractures. In supin ation in juries, the lateral side of the an kle is affected first, wh ereas in pron ation in juries, th e m edial sided structures fail first. Th e m ech an ism of in jury is often reflected by the fracture pattern of the fibula. For supin ation injuries, th e fibula fracture follows a predictable an teroin ferior to posterosuperior pattern, whereas in pronation in juries, th e opposite pattern is com m onplace with th e fracture lin e run n in g from an terosuperior to posteroin ferior. A transverse fibula fracture with lateral com m inution, often represen ted as a butterfly fragm en t, typifies pron ation abduction in juries. Supin ation -adduction in juries are typically tran sverse avulsion fractures of th e distal fibula fractures at or below th e joint lin e. Un fortunately, the Lauge–Hansen classification h as low in terobserver reliability, does n ot direct treatm en t, an d does n ot predict prognosis. Nevertheless, it is com m only used an d is useful for conceptually understanding this injury. Beyond describing the gross m orphology of fractures, it is often m ore h elpful to classify an kle fractures as stable an d un stable. Stable fractures h ave th e ability to resist displacem en t un der physiological loads, wh ereas un stable pattern s do n ot. In gen eral, stable fractures carry a better progn osis an d can be treated n on operatively. Un stable fractures m ost often n eed surgical reduction an d in tern al fixation . A Maisonneuve variant is a particular type of ankle fracture associated with a h igh fibular fracture. Th e extern al rotation force exerted on th e an kle propagates from th e deltoid ligam en t th rough th e in terosseus m em bran e an d exits th rough th e proxim al fibula creatin g th e ch aracteristic fracture pattern an d in stability of th e an kle.

Mechanism of Injury Ankle fractures usually result from low-en ergy forces that have a rotational component as seen in athletic activities or sligh t falls. Presentation Patien ts present with acute ankle pain and swellin g and, often , th e in ability to bear weigh t. Physical Examination Ecchym osis and swelling are usually present. Obvious deform ity is a sign of an associated dislocation. Impendin g open an d open in juries are un com m on , but a th orough exam in ation of th e skin is im perative. A n eurovascular exam in ation is required before an d after any m an ipulation

of th e extrem ity. Th e en tire len gth of th e tibia an d fibula sh ould be palpated, especially the proxim al fibula, to evaluate for a Maison n euve fracture.

Imaging Stan dard radiograph s are sufficien t for m ost an kle in juries. Stress radiograph s h elp rule out a syn desm osis in jury. Th e Ottawa Ankle Rules provide direction as to when radiograph s are in dicated. Th ese four rules drastically decreased the num ber of radiographs perform ed in em ergen cy departm en ts wh ile m ain tain in g 100% sen sitivity. If a patien t is 55 years or older, un able to bear weight, or has bon e tendern ess alon g th e posterior edge or tip of eith er m alleoli, a radiograph is in dicated. In a n orm al an kle, th e talus sh ould sit under th e tibia with a tibiotalar space that is equal to the distan ce from lateral border of th e m edial m alleolus to th e m edial border of th e talus on the m ortise view, or approxim ately 4 m m (Fig. 19.13A–D). Any tran slation of th e talus indicates an unstable fracture pattern . The talocrural angle helps to judge fibular length and is usually 83 degrees (Fig. 19.13B). Th e tibiofibular clear space is th e best way to evaluate an un stable syn desm osis in jury on radiograph . It is the distance between the m edial fibula and the incisura of th e tibia m easured 1 cm above th e join t; it sh ould be less th an 6 m m (Fig. 19.13D). This m easurem ent is m inim ally affected by rotation. The entire length of th e tibia an d fibula should be im aged if there is any concern for a proxim al fracture lin e. Differential Diagnosis A pilon fracture, simple an kle dislocation , subtalar dislocation, and even severe ankle sprain can also present with eith er a deform ity or an an kle swellin g. In addition , patients m ay describe an kle pain , when in reality the foot is the site of pathology, for example, in a fracture of the base of th e fifth m etatarsal. Appropriate im agin g studies aid in determ in in g th e correct diagn osis. Treatment If th e in jury is a fracture-dislocation , th e an kle sh ould be reduced im m ediately. Defin itive treatm en t is depen den t on stability of th e fracture pattern . Stable fibula fractures, displaced less th an 5 m m , with out a m edial an kle in jury can be treated with a walking cast or a fracture boot for 6 weeks. A fracture boot is n ecessary on ly for am bulation an d thus can be rem oved for ran ge-of-m otion exercises to preven t stiffn ess. It is importan t to repeat radiograph s at 1 week to ensure there is n o late displacem en t. For un stable fractures, operative in terven tion is recom m en ded. Th e fibula is usually approach ed first. Wh en possible, an in terfragm en tary screw sh ould be placed from th e proxim al fragm ent into the distal fragm ent and perpendicular to the fracture line. A n eutralization plate provides rotational stability to th e con struct. Recen tly, th ere h ave been a n um ber


767

Mortise view

≤4 mm

A

Normal

A

B

Talocrural angle (83˚± 4˚)

C

Medial clear space

B B

A

Figure 19.13 The commonly used radiographic markers for evaluating

D

Ant

Tibiofibular clear space (A-B)

ankle stability. The normal ankle (A). The talocrural ankle estimates fibula length and is most accurate when compared with the uninjured side (B). The medial clear space should be equal to the space between the tibia and talus or 4 mm or less (C). The tibiofibular clear space is the most reliable radiographic finding (D). It should measure less than 6 mm. (Reproduced with permission from Rockwood CA, Green DP, Bucholz RW. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

of precon toured plates in troduced, wh ich can sim plify plate application. The m edial m alleolus should then be reduced an d fixed with two cancellous screws or with a tension band tech n ique if th e fragm en t is sm all. On rare occasion s, a torn deltoid m ay flip in to th e join t an d im pede reduction . Wh en this is the case, an arthrotomy is perform ed to rem ove the interposed ligam ent, otherwise a deltoid tear does n ot usually require repair. The stability of the syndesm osis m ust be ch ecked on all ankle fractures before leaving the operating room . If there are signs of instability, one 4.5 m m or two 3.5 m m screws sh ould be placed from th e lateral fibula across the syn desm osis and into the tibia. The screws can en gage on e or both of th e tibia cortices depen din g on surgeon preference. To avoid overcom pression of th e syn desm osis, th e screw sh ould be a fully th readed cortical screw placed parallel to the joint, an d inserted with out using a lag techn ique. Most surgeons rem ove the syndesm osis

screw(s) 12 weeks followin g surgery. A separate posterior m alleolus fragm en t requires repair on ly wh en it is greater than 25% of the articular surface. Postoperatively, patients are usually m ade touch down weigh t-bearin g for 6 weeks. Startin g ran ge of m otion early in th e postoperative course decreases swellin g an d stiffn ess.

Ankle Sprains and Syndesmosis Injuries An kle sprain s are th e m ost com m on sports-related in juries and can result in chronic pain an d/ or instability if not treated appropriately. Injury to the lateral side of the ankle occurs in m ost of th e cases, with th e ATFL bein g th e m ost com m on ly in jured structure. Th e CFL is in volved in approxim ately 50% of cases, wh ereas PTFL in jury occurs in less than 10%. Syndesm otic injuries are often referred to as “h igh ankle’’sprain s.

768


Classification It is easiest to divide an kle sprain s in to acute in juries an d ch ron ic in stability. Ch ron ic in stability results from repeated sprain s an d m an ifests as persisten t pain an d a feelin g of givin g way. Acute sprain s are graded on th e basis of severity. In grade I in juries, the ATFLis stretched or partially torn , with out complete disruption . Pain , swellin g, an d ten dern ess over th e ATFLare ch aracteristic of th is in jury. Th ere is, h owever, n o laxity appreciable on physical exam in ation . Grade II in juries in volve a complete tear of th e ATFL an d m ay in clude in jury to th e CFL. Laxity m ay be eviden t. In grade III in juries, th e ATFL an d CFL are torn , an d th e PTFL or an terolateral capsule of th e an kle join t m ay also be affected. There is a complete loss of the n orm al hindfoot contours due to swelling. Mechanism of Injury Th e n orm al m ech an ism for lateral sided in juries is plan tarflexion -in version . In version in juries occurrin g with the ankle positioned in n eutral or in dorsiflexion create isolated CFL disruption or subtalar dislocation . An extern al rotation -eversion in jury m ay cause a sprain of th e deltoid an d syn desm otic ligam en ts. Isolated syn desm osis in juries result from dorsiflexion -eversion in juries. Presentation Th e patien ts typically presen t with pain , swellin g, an d ecchym osis over th e lateral side of th e an kle depen din g of the severity of injury. With higher grades of injury, patien ts ten d to h ave sign ifican t difficulty bearin g weigh t. Physical Examination Th e origin s an d in sertion s of th e an kle ligam en ts sh ould be palpated, but th is can be difficult in th e presen ce of significant swelling. As pain allows, the ankle is tested for eviden ce of in stability. Th e an terior drawer test, a test of th e ATFL, is perform ed with the ankle in 10 degrees of plantarflexion . Wh ile stabilizin g th e tibia, an an teriorly directed force is applied to th e hindfoot. Translation of the talus is an in dication of in competen ce of th e ATFL an d is m easured in m illim eters. Grade I in juries h ave m in im al tran slation with a firm en dpoin t. Grade II in juries h ave laxity but a firm en dpoin t, wh ereas grade III in jures h ave a soft en dpoin t. For th e talar tilt test, wh ich stresses th e CFL, th e hindfoot is inverted with the an kle h eld in m axim al dorsiflexion. Translation an d tilt of the talus with varus stressin g is compared with th e un in jured side. The fibular squeeze test, perform ed by squeezing th e fibula an d tibia togeth er at th e m idpoin t of th e calf, elicits pain with syn desm osis in jury. Th e extern al rotation test, in wh ich th e foot is extern ally rotated with th e an kle in neutral flexion and th e knee flexed to 90 degrees, produces pain over th e in terosseous m em bran e an d distal tibiofibular join t wh en a syn desm osis in jury is presen t.

Imaging Stan dard th ree an kle views are obtain ed to rule out fracture or fran k tran slation of th e talus. Stress views can be h elpful to diagn ose ligam en t tears of th e lateral side of th e an kle. Anterior translation of greater than 5 m m is considered abn orm al. There is no consen sus on the degree of talar tilt that is abnorm al, but if there is doubt, a stress radiograph of th e un in jured an kle can be taken for com parison . To assess syndesm otic injury, weight-bearing radiographs and extern al rotation stress views can be obtain ed to evaluate m ortise widen ing. Differential Diagnosis Th e differen tial diagn osis of lateral h in dfoot in juries associated with a plantarflexion-in version m echanism includes peron eal ten don tears, peron eal ten don subluxation or dislocation , and fractures of th e an terior process of the calcan eus, base of th e fifth m etatarsal, lateral process of th e talus, an d os trigon um . Treatment Grade I an d II an kle sprain s are un iform ly treated with rest, ice, compression, elevation, (RICE) an d protected weightbearin g for 5 to 7 days, followed by physical th erapy em ph asizin g proprioception usin g tram polin es or wobble boards, stren gth en in g, an d stretch in g. Th e reh abilitation protocol th en focuses on agility an d sport-specific exercises to return the patient to the previous level of ath letic activity and prevent recurrent sprains. Grade III sprains are treated with a brief period of im m obilization followed by reh abilitation , fun ction al reh abilitation alon e, or surgical repair. Im m obilization for 3 weeks with eith er a walkin g cast or a rem ovable walker boot with th e ankle in n eutral or 10 degrees of dorsiflexion to approxim ate th e torn en ds of th e ATFL sh ould be reserved for low-dem an d patien ts. After the period of im m obilization, rehabilitation is the sam e as that for grade I and II injuries. For athletes, it is best to avoid im m obilization an d associated stiffn ess, by initiatin g early m obilization with the protection of an extern al support, such as a lace-up brace or Aircast. Tapin g is less effective as it loosens rath er rapidly during athletic activity. Patients treated with early m obilization h ave higher satisfaction rates th an those treated with cast im m obilization and return to sports earlier. While there is no good eviden ce to support it, an atom ic repair is an option for h igh -perform ance ath letes. Ch ron ic an kle in stability requires surgery wh en fun ctional rehabilitation fails to relieve pain and symptom s of giving way. Surgical reconstruction can be either an atom ic or n on an atom ic. An atom ic recon struction s recreate n orm al ankle and subtalar m otion and m echan ics, whereas n on anatom ic reconstruction s do n ot. Th e Brostrum procedure is th e m ost popular an atom ic procedure, in wh ich the ruptured ligam en t en ds are im bricated an d retension ed. Variation s in clude shortening the ligam en ts due to


attenuation an d reinforcem ent with the exten sor retinaculum (Gould m odification ) or fibular periosteum . There are a num ber of n on-an atom ic reconstruction s that use a portion of the peroneus brevis tendon, free gracilis autograft ten don , or an allograft ten don to stabilize th e lateral an kle. Th ese m ore robust recon struction s h ave a greater complication rate with m otion loss, woun d healing, an d sural nerve injury as the m ost com m on. At the tim e of surgical interven tion, all patien ts should un dergo an ankle arthroscopy, as the rate of intraarticular pathology associated with chron ic instability is as high as 90%. Injuries include osteoch on dral lesions of the talus, chondrom alacia, m eniscoid lesions, an d an terior impin gem en t from osteophytes. Appropriate treatm ent of these associated injuries increases the chance of successful resolution of sym ptom s.

Achilles Tendon Ruptures Th e Ach illes ten don is th e largest an d stron gest ten don in the body. Acute ruptures com m only do not have antecedent symptom s and occur in m iddle-aged m en wh o are in m oderately poor physical con dition , at a rate of 18 per 100,000. Treatm ent strategies have changed over the last 20 years, but th ere is n o con sen sus on th e ideal treatm en t.

Pathophysiology and Classification Ruptures m ost com m only occur 2 to 6 cm proxim al to the insertion site of th e tendon in the hypovascular zone (Fig. 19.14). Most com m on ly, th e in jury is th e result of a forceful eccen tric con traction ; h owever, un con trolled dorsiflexion of th e an kle an d rarely direct traum a m ay also be respon sible. When rupture occurs from a trivial event, on e m ust rule out m etabolic abnorm alities, inflam m atory arth roses, an d steroid and fluoroquin olone use.

Figure 19.14 Ruptures of the Achilles tendon occur 4 to 6 cm

proximal to the insertion on the calcaneus, which is a relative hypovascular zone. (Reproduced with permission from Kitaoka HB. The Foot and Ankle. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2002.)

769

Presentation Patien ts presen t after a severe, sudden pain in th e back of th e calf th at is described as bein g struck from beh in d and is often associated with swelling. Unfortunately, the pain resolves rath er quickly an d som e m ay still be able to participate in sportin g activities, wh ich con tributes to th e 25% rate of m issed an d delayed diagn oses. Physical Examination Diagn osis is m ade by palpatin g a defect 2 to 6 cm above th e in sertion of th e Ach illes ten don . It is often accen tuated by holding the foot in m axim al dorsiflexion , which places th e Ach illes on stretch . In obese patien ts an d in dividuals with severe swellin g, a gap m ay n ot be eviden t. Stren gth of th e gastrocsoleus com plex can be tested by h avin g th e patien t perform a sin gle-leg h eel rise or by testin g plan tarflexion again st resistan ce. Because of th e participation of th e posterior tibialis m uscle an d toe flexors, patien ts can h ave rather sign ifican t plan tarflexion stren gth even with an Ach illes rupture. Havin g the patien t lie prone on the exam ination table is helpful. Th e passive restin g tension of the tendon and position of th e foot sh ould be n oted. With a defect in th e Ach illes ten don , th e foot rests at 90 degrees to th e body com pared with th e un affected extrem ity, wh ich rests in relative plantarflexion. Asim ilar observation can be m ade with th e kn ee flexed to 90 degrees accordin g to th e Matles test. Th e torn side will fall in to relative dorsiflexion with gravity and th e loss of tension from the Achilles tendon. The Th ompson , or calf squeeze, test is perform ed by squeezin g th e m id portion of th e gastrocn em ius, wh ich sh ould result in passive plantarflexion of the foot if th e Achilles tendon is in con tinuity (Fig. 19.15).

Figure 19.15 The Thompson test evaluates the continuity of the

gastrocsoleus complex. When intact the complex is intact, squeezing the midcalf results in plantarflexion of foot. (Reproduced with permission from Rockwood CA, Green DP, Bucholz RW. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

770


Radiographic Findings Radiograph s m ay reveal blun tin g of th e retrocalcan eal space or rarely a bony avulsion fracture of th e posterior calcaneus. Special Tests If th ere is any con fusion in th e diagn osis, ultrasoun d an d MRI are useful in evaluatin g th e con tin uity of th e ten don . MRI also provides th e added ben efit of revealin g any degen erative ch an ges of th e ten don th at m ay h ave played a role in th e rupture. In up to 25% of cases, patien ts report previous symptom s in th e Ach illes. Path ological studies h ave in dicated all ruptured ten don s h ave som e degree of degen eration prior to rupture. Treatment Historically, Achilles tendon injuries were treated non operatively because of woun d complication rates approach in g 30%. However, m ore recen tly, th e relatively h igh rerupture rates have lead surgeons to surgical in tervention. Nonoperative treatm en t typically in volves 6 to 8 weeks in a n on – weigh t-bearing cast with the foot in gravity equinus followed by an addition al 4 weeks in a walkin g cast. After th is period of im m obilization , a supportive lace-up sh oe with a heel lift is worn for an addition al 1 to 2 m on th s. Som e authors support weight-bearing from the outset of treatm ent an d th e use of fun ction al bracin g rath er th an castin g. Th e advan tage of n on operative m eth ods is th e avoidan ce of surgical complication s, m ost n otably woun d breakdown an d in fection . Th e m ajor disadvan tage of n on operative treatm en t is th e rerupture rate of approxim ately 13%. Oth er disadvan tages in clude a lon ger tim e before return in g to work an d activity. The high rates of woun d complication s have often deterred surgeon s from pursuin g surgery for th e treatm en t of Ach illes ten don ruptures. However, with advan ces in tech n iques, th ese rates h ave dropped. Th ese in juries can be approach ed in an open fash ion or percutan eously an d sh ould be repaired within 7 to 14 days. When perform in g th e surgery open , it is imperative to respect th e soft tissue en velope. Th e ten don is repaired en d-to-en d, usin g a Krackow stitch with n on absorbable h eavy suture. Obtain in g appropriate ten sion of repair is difficult but usin g the plantaris tendon and observing the resting posture of the foot can be helpful. The paratenon should be closed over th e repair, an d th e skin flaps sh ould be closed with a no-touch technique. Som e have advocated for augm en tation of th e repair with gastrocn em ius fascia, th e plan taris, or artificial m aterials; h owever, th ese h ave yet to h ave a proven ben efit. Wh ile percutan eous tech n iques m ay h ave less woun d complication s, th e suture placem en t m ay n ot be optim al an d th ere is a greater ch an ce of sural n erve in jury. O perative in terven tion also allows for early fun ction al rehabilitation (weight-bearin g an d range of m otion), wh ich is th ough t to h asten th e h ealin g of th e ten don .

Th ere is n o con sen sus on optim al treatm en t for acute ten don ruptures. Non operative treatm en t is effective; h owever, th ere is a sign ifican t rerupture rate. Operative treatm ent with early functional rehabilitation results in a quicker return to full fun ction an d a lower rerupture rate at th e sacrifice of woun d com plication s. Percutan eous treatm ent is an attempt to m inim ize the m ajor complications of each group; h owever, th ere is th e risk of sural n erve in jury. Chronic ruptures are Ach illes ten don s th at go un treated for 4 to 6 weeks due to a delayed diagnosis. Patients often complain of weakn ess with out sign ifican t pain . Th e pain an d swellin g associated with th e in itial in jury subsides fairly quickly. Fibrous scar tissue does form between ten don en ds; h owever, it does n ot restore correct ten sion or strength . Patien ts are able to plantarflex th e foot by recruitin g th e FHL, FDL, posterior tibialis an d peron eal m uscles but with relative weakn ess. On e sh ould also observe for calf wastin g, claw toes, an d a h igh arch deform ity as a result of the FDL activity. Managem ent is typically operative unless the patient has low dem ands or is not healthy enough to un dergo surgery. For n on operative treatm en t, an an kle foot orth osis (AFO) sh ould be prescribed. Th ere are n um erous option s for surgical recon struction , m ost of wh ich in volve augm en tation with a graft. Th e peron eus brevis, FDL, FHL, fascia lata, gracilis, and allografts have all been described. Un fortun ately, fun ctional results are not as predictable as those after repair of acute Achilles tendon ruptures.

Talus Fractures Fractures of th e talus are typically h igh -en ergy in juries th at are difficult to treat and can be debilitating even when treated appropriately. Fractures can involve th e head, n eck, body, lateral process, an d posterior process. Displaced body an d neck fractures require extra diligence and are treated as em ergen cies due to th e associated com plication s.

Classification Talus fractures are m ost easily divided by the anatom ic location, that is, head, neck, body, lateral process, and posterior process. Talar n eck fractures are furth er classified on the basis of a description by Hawkins, which was subsequen tly m odified by Can ale (Fig. 19.16). Type I fractures are nondisplaced fractures without an associated join t dislocation . Type II fractures are displaced with subluxation or dislocation of th e subtalar join t. Type III fractures h ave dislocation s of th e subtalar join t an d th e an kle. Type IV fractures have dislocations of th e subtalar, ankle, and talon avicular joints. The risk of osteonecrosis increases with th e injury grade such th at nearly all type IV fractures develop osteon ecrosis. Mechanism of Injury Talar n eck fractures, historically referred to as aviator astragalus, result from hyperdorsiflexion with an axial load usually from a fall from height or a m otor vehicle crash. As the


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A

B

C

D

Figure 19.16 The Hawkins classifica-

tion of talus fractures. (Reproduced with permission from Kitaoka HB. The Foot and Ankle. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2002.)

foot dorsiflexes, the neck of the talus impacts the an terior distal tibia. Wh en th ere is sufficien t force, th e body of th e talus can displace posterom edially to lie beh in d th e m edial m alleolus, rotating on the deltoid ligam ent. Fractures of the talar body result from h igh -im pact axial loadin g, m ost com m on ly m otor vehicle crashes, an d are associated with talar neck fractures in about 40% of cases. Axial loading is also respon sible for h ead fractures, but th e forces are tran sm itted through th e navicular. Lateral process fractures com m only occur wh ile sn owboardin g an d result from an kle in version an d dorsiflexion with axial loading. Posterior process fractures occur from avulsion or direction compression. With inversion of the ankle, th e PTFL can avulse the process; however, direct compression of the process between th e calcaneus and tibia is the m ore com m on m echanism .

Presentation Wh en resultin g from h igh -en ergy traum a, patien ts will h ave swellin g and deform ity if a dislocation is presen t. Lowen ergy m ech an ism s m ay presen t sim ilar to an kle fractures or sprain s.

Physical Examination A th orough n eurovascular an d skin exam in ation is imperative. It is importan t to rule out other injuries that require em ergen t treatm en t. Imaging AP, lateral, an d m ortise views of th e an kle provide good visualization of the talar body, n eck, and processes. Additional inform ation con cern ing the m edial talar n eck can be obtain ed by position in g th e an kle in plan tarflexion , th e foot in 15 degrees of pronation , and directing the beam 75 degrees to the perpen dicular (Fig. 19.17). This view is especially h elpful in th e operatin g room to con firm adequate reduction . CT can h elp to furth er defin e th e fracture pattern an d plan surgical reduction . MRI is less useful acutely but is a sen sitive test for avascular n ecrosis. Differential Diagnosis Low-energy in juries such as lateral process fractures can resem ble an kle sprain s an d fractures due to th eir sim ilar m echanism of injury. The swelling and ecchym osis of

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75°

15°

Figure 19.17 The Canale and Kelly view for evaluation of the

talar neck. (Reproduced with permission from Rockwood CA, Green DP, Bucholz RW. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

high-energy m ech anism s can resem ble calcan eus an d pilon fractures.

Treatment Talar neck and body fractures are true orthopaedic em ergen cies. Displaced fractures an d join t dislocation s require im m ediate reduction to decrease th e risk of osteon ecrosis an d protect th e overlyin g soft tissue. Th e goal of defin itive treatm en t is to m ain tain an atom ic reduction wh ile m in im izin g posttraum atic arth rosis, osteon ecrosis, an d varus m alalign m en t. Varus m alalign m en t greater th an 5 degrees an d displacem en t m ore th an 5 m m h ave adverse effects on the kinem atics of the h indfoot. All displaced talar neck fractures require reduction and surgical fixation . Nondisplaced fractures can be treated successfully closed but m ust be m on itored closely with serial im aging. Non –weight-bearin g is m aintained for at least 6 weeks or un til th ere is eviden ce of revascularization . Surgical fixation can be perform ed eith er percutan eously through a posterolateral approach or open via an anterom edial approach . In th e an terom edial approach , th e in terval of dissection is between th e tibialis an terior ten don an d th e tibialis posterior ten don . Th is allows for adequate visualization of th e m edial aspect of th e n eck an d can be exten ded by a m edial m alleolar osteotomy. Fixation con structs are usually screws supplem ented with sm all plates if com m in ution is presen t. Postoperatively, th e patien t is im m obilized an d m ade n on –weigh t-bearin g for at least 6 weeks. To avoid stiffn ess early range of m otion can be initiated. Sign s of osteon ecrosis typically m an ifest by 8 to 10 weeks. The Hawkins, or crescent, sign seen on AP an d m ortise radiograph s is an in dication of a viable talar body. With sufficien t vascularity th e talar body will be relatively os-

teoporotic compared with th e surroun din g bon e because of disuse an d revascularization . Th is is differen tiated from den se, sclerotic bon e seen with osteon ecrosis. MRI is useful to evaluate for osteonecrosis. Other m ajor complication s include skin necrosis, infection, m alunion, n onunion, an d posttraum atic arth ritis. Varus m alun ion h as a lockin g effect on th e m idfoot an d m ay occur in up to 50% of type II, III, and IV fractures. Posttraum atic arthritis of the ankle and subtalar join ts can result from avascular necrosis, articular dam age, m alun ion , an d prolon ged im m obilization . Sim ilar to talar n eck fractures, talar body fractures with associated joint dislocation require em ergent reduction. Surgical fixation is recom m ended for nearly all body fractures an d is usually accomplished with cortical screws. Non displaced h ead fractures are treated con servatively in a sh ort-leg, non –weight-bearing cast. Sm all, displaced fractures can be excised or rigidly fixed with headless screws coun tersun k below th e articular surface. Head fractures often result in talon avicular arth ritis. Th e treatm en t of lateral process fractures m ain ly depen ds on th e size of th e fragm en t an d degree of com m in ution. Non displaced or fractures with sm all fragm ents are treated with cast im m obilization and progressive weightbearin g. Larger fragm en ts th at are displaced are treated with ORIF. Posterior process fractures are treated with a non – weigh t-bearin g cast for 4 weeks followed by a walkin g cast for 2 weeks. Excision of symptom atic fragm ents is recom m ended for persistent pain in the retrom alleolar area especially with forced plan tarflexion .

Osteochondral Lesions of the Talus Osteochondral lesions of th e talus are a relatively com m on cause of ankle pain and are m ost often related to ankle traum a and chronic an kle instability. Although com m only used for all lesion s of th e talus, th e term osteochondritis dissecans (O CD) refers specifically to the nontraum atic spontan eous n ecrosis of bon e. Osteochondral lesion is probably m ore encompassing and appropriate term for the m ajority of talus articular injuries. The workup and treatm ent of th ese lesion s h ave ch an ged with th e adven t of an kle arthroscopy an d the advances m ade in the treatm ent of cartilage lesion s in the knee.

Pathophysiology and Classification Osteochondral lesions of the talus are best broken down into traum atic and atraum atic causes. Injury to the talus can occur with an ankle injury or with chronic ankle in stability. Nontraum atic causes include ossification defects, abn orm al vasculature, em boli, and endocrin e disorders. Lesions are typically seen posterom edially an d an terolaterally. Lateral lesions are alm ost universally related to traum a resulting from inversion an d dorsiflexion. Traum a is also the cause of m ost m edial lesions; h owever, there is a sign ificant in ciden ce of n ontraum atic lesion s of the m edial side. Traum atic lesions on the m edial aspect of the talus


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occur with in version , plan tarflexion , an d extern al rotation forces. Berndt and Harty described the classification referen ced m ost frequently on the basis of radiograph s. Stage I den otes a lesion with a sm all area of subch on dral compression . In stage II lesions, there is an osteochon dral fracture th at is on ly partially displaced. If th e osteoch on dral fragm en t is completely detach ed but rem ain s in the bed, it is considered stage III. Stage IVlesions are com pletely displaced from th e bed. Num erous classification s h ave sin ce been described on th e basis of CT an d MRI accoun tin g for th e presen ce of sclerosis an d subch on dral cyst form ation . However, in traoperative findings during arthroscopy are probably th e m ost reproducible and prognostic.

Presentation Th e h igh est in ciden ce occurs in th e th ird decade of life. Complaints of chronic ankle pain with or without interm ittent swelling an d instability after an episode of m inor traum a such as an inversion ankle sprain is com m on. Locking can occur if the lesion becom es displaced. Physical Examination Th e an kle sh ould be exam in ed for sign s of join t laxity. An terolateral lesion s can be ten der to palpation with th e an kle in m axim um plantarflexion. Tenderness behind the m edial m alleolus with the foot in m axim um dorsiflexion can be a sign of a posterom edial lesion . Radiographic Findings Stan dard an kle radiograph s are sufficien t to diagn ose lesions with evidence of a subch on dral fracture (Fig. 19.18), subch on dral cysts, or localized sclerosis.

Figure 19.18 A posteromedial osteochondral lesion is seen

on a standard radiograph. (Reproduced with permission from Kitaoka HB. The Foot and Ankle. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2002.)

Figure 19.19 A coronal magnetic resonance image showing a

posteromedial lesion of the talar dome. (Reproduced with permission from Kitaoka HB. The Foot and Ankle. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2002.)

Special Tests MRI is highly sensitive for iden tifyin g lesions before changes are apparent on radiographs (Fig. 19.19). MRI has th e added ben efit of providin g in sigh t in to th e stability an d viability of the fragm ent. A CT scan can be useful for surgical planning and accurately iden tifyin g the location and exten t of th e bon e lesion . Treatment Stage I and II lesions are treated with im m obilization in a n on –weigh t-bearin g sh ort-leg cast for 6 to 12 weeks. Non operative treatm en t is effective in less th an 50% of cases overall. Stage III an d IV lesion s an d stage I an d II lesion s th at do n ot respon d to n on operative treatm en t sh ould be treated operatively either arthroscopically or through an open approach . Treatm en t option s in clude ch on droplasty, debridem en t an d in tern al fixation , an terograde or retrograde drillin g, excision with m arrow stim ulation , excision with osteoch on dral tran splan tation , or excision alon e. Th e stability of the lesion , size of the lesion , an d condition of th e cartilage determ in e outcom e. Ch ondroplasty is the simplest intervention . The goal is to restore a stable edge to the lesion . Drilling of the subch ondral lesion to stim ulate healing can be perform ed usin g eith er an an terograde or retrograde tech n ique. Retrograde drillin g tech n iques avoid in jury to th e cartilage. If th e fragm en t is n ot salvageable, it sh ould be excised an d th e lesion debrided. The resulting defect is treated with a m icrofracture tech n ique to stim ulate fibrocartilage form ation . Altern ative option s in clude th e tran splan t of osteoch on dral autograft plugs taken from th e n on –weigh t-bearin g portion of th e kn ee in to th e defect or th e use of autologous chon drocyte transplantation.

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There have been no good studies comparing the outcom es of the various treatm en t m ethods; however, th ere does appear to good sh ort-term results regardless of th e treatm en t tech n ique.

Calcaneus Fractures Th e calcan eus is th e m ost com m on ly fractured tarsal bon e usually resultin g from axial loadin g durin g falls or m otor veh icle crash es. Seven ty-five percen t of th ese fractures are in traarticular an d com m in uted, m akin g th em ch allen gin g to treat. Th e severity of th ese in juries is h igh ligh ted by th e fact th at 25% of patien ts will have an associated lower extrem ity fracture an d 10% a spin e fracture. Un fortun ately, even appropriate treatm en t can result in lon g-term disability.

Classification Fractures were h istorically classified accordin g to radiograph s but are n ow m ore com m on ly classified by in form ation obtain ed with a CT scan . Fractures are divided in to extraarticular or in traarticular types. Extraarticular fractures in volve th e an terior process, th e tuberosity, th e body, th e m edial process, an d th e lateral process. In traarticular fractures based on radiograph s are divided in to ton gue-type an d join t-depression -type fractures. With th e ton gue-type fractures, th e posterior facet rem ains attach ed to th e tuberosity fragm en t, wh ereas in th e join t-depression -type, th e fragm ents are separate. Th e m ost com m only used classification for intraarticular fractures is the San ders classification based on coron al CT im ages taken th rough th e widest aspect of th e posterior facet (Fig. 19.20). Th e location an d num ber of fragm en ts determ in es the type. The posterior facet is divided in to th ree colum n s—th e lateral, cen tral an d m edial—or A, B, an d C, respectively. Non displaced fractures regardless of th e n um ber of fracture lin es are type I. Type II, III, an d IV fractures h ave two, th ree, an d four fracture lin es, respectively. Each type is th en am en ded on th e basis of wh ere th e in dividual fracture lin es en ter th e join t with the letters A, B, and C. Mechanism of Injury High-energy injures includin g falls from h eights and m otor veh icle crash es are th e usual cause of calcan eal fractures. Because of the force involved, th ey are often associated with spin e fractures. The position of the foot determ in es th e exact fracture pattern . As th e lateral talar process is driven in to the superior calcaneal surface, a prim ary fracture line runs from th e posterior facet in a lateral to posterom edial direction , creatin g an terom edial an d posterolateral fragm en ts. Th e an terom edial fragm en t usually con tain s th e susten taculum tali, wh ich is n on displaced because of its attach m en ts to th e talus via th e in terosseous ligam en t, an d is often called the “constant’’ fragm ent. Secondary fracture lines m ay

occur an d exten d th rough th e calcan eocuboid join t an d lateral calcaneal wall. Extraarticular fractures of th e calcan eus are typically lower-en ergy and occur by different m echanism s. Forced dorsiflexion from a fall can result in avulsion of th e tuberosity via the pull of the Achilles tendon. In version and plan tarflexion in juries can result in in jury to th e an terior process of th e calcan eus. Body fractures of th e calcan eus with out exten sion in to th e subtalar join t are also possible.

Presentation Pain and swelling m ay be the only presenting complaints for low-energy injuries such as those of the anterior process and tuberosity. Patients with h igh-en ergy, intraarticular fractures are often in significant pain and have obvious deform ities. In addition , th ese patien ts often h ave oth er injuries. Physical Examination Determ in in g th e appropriate tim in g an d treatm en t for calcaneus fractures requires adequate assessm ent of th e soft tissues. Fracture blisters, open wounds, an d compartm ent syn drom e effect h ow th ese injuries are approached. It is essential to respect th e soft tissue envelope, as failure to do so h as devastatin g consequen ces. Patien ts sh ould be evaluated for lower extrem ity fractures. The entire spine, especially the lum bar spine, should be inspected and palpated. Imaging AP, lateral, the Harris h eel, and Broden views should be initially taken for diagnosis. In addition, radiographs of the pelvis and thoracolum bar spine m ay be indicated to rule out associated fractures. Helpful radiographic angles, the tuber angle of Bö h ler, an d th e crucial an gle of Gissan e are m easured on the lateral view (Fig. 19.21). The tuber angle of Bö h ler is form ed by th e m ost posterosuperior aspect of th e calcan eal tuberosity, th e posterior facet, an d th e anterior process and is norm ally 20 to 40 degrees. With fracture and collapse of the posterior facet, this angle decreases. The crucial an gle of Gissane is form ed by lateral m argin of the posterior facet and a strut of bone leading to the beak of the calcaneus and usually m easures about 100 degrees. With fracture of the posterior facet and collapse the angle increases. The Harris heel view assesses the loss of height, increase in width , and m alalignm en t of the calcaneal tuberosity, usually into varus (Fig. 19.22). The Broden view h elps to assess th e status of th e posterior facet. Th e view is sim ilar to a m ortise view of th e an kle with th e foot in internal rotation, an d by changing the angle x-ray beam , differen t aspects of th e posterior facet are visualized (Fig. 19.23). With th e wide availability of CT scans, they are n ow becom in g a stan dard radiograph ic study. Th ese scans provide fast an d accurate views of th e fracture pattern an d am ount of displacem ent of the posterior facet that is critical in directin g surgical interven tion.


A

Ce ntral Med. Su st .

Lateral

A B C

B

Typ e IIA

A B

C

Typ e IIB

A

C

Typ e III AB

Typ e IIC

BC

Typ e III AC

Typ e III BC

A B C

Type IV

Figure 19.20 The Sanders classification of calcaneus fractures. This is based on coronal computed tomography images taken through the widest aspect of the posterior facet, which is divided into three columns (A–C). The number of displaced fractures determines the subtype. (Reproduced with permission from Rockwood CA, Green DP, Bucholz RW. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

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776


B

A

Figure 19.21 The crucial angle of Gissane (A) and the tuber angle of Bohler ¨ (B) help to identify

calcaneus fractures and to evaluate adequacy of reduction. (Reproduced with permission from Rockwood CA, Green DP, Bucholz RW. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Differential Diagnosis High-energy in juries are usually obvious. Anterior process fractures can be m istaken for ankle sprains. Treatment Calcan eus fractures are ch allen gin g to treat, an d th is is m ade m ore complicated by a lack of con sen sus on acceptable treatm ent. Nonoperative treatm ent is typically reserved for n ondisplaced fractures. However, recen t studies have shown better functional outcom es with nonoperative treatm en t for sm okers, laborers, patien ts in volved in workers’ com pen sation suits, bilateral in juries, an d fractures with significan t com m in ution of th e posterior facet. Cast im m obilization for approxim ately 3 m on th s is required

Figure 19.22 A Harris heel view showing a loss of height, in-

crease in width, and varus alignment of the calcaneus. (Reproduced with permission from Rockwood CA, Green DP, Bucholz RW. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

before weigh t-bearin g is in itiated. Displaced fractures treated n onoperatively usually result in m alunions, which can lead to tibiotalar impingem ent with loss of ankle dorsiflexion an d calcaneofibular abutm ent with peroneal tendon en trapm en t or dislocation . Varus m alun ion alters th e an kle and hindfoot kinem atics, resulting in a locked forefoot and am bulating on the outer border of the foot. Plan tarflexion stren gth is also lost because of th e altered m ech anics of the Achilles tendon. Th e goal of operative in terven tion is to restore th e articular con gruity an d avoid th e com plication s of m alun ion . Surgery sh ould be perform ed with in 3 weeks but delayed long enough to allow th e soft tissue envelope to calm down, usually about 7 to 10 days. Un til surgery, th e leg is m ain tain ed in a Jon es dressin g an d elevated. Wh en wrin klin g of the skin over the lateral hindfoot returns, it is usually safe

Figure 19.23 Broden view is similar to the mortise view of the

ankle and helps in assessment of the posterior facet. An intraarticular fracture is denoted with arrows. (Reproduced with permission from Rockwood CA, Green DP, Bucholz RW. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)


to proceed. Surgical dissection is carried laterally usin g an L-shaped incision with a full-thickness subperiosteal flap including the peron eal tendons, sural nerve, an d CFL. Fixation involves initially reducin g an d stabilizing the posterior facet an d th en attach in g th e lam in ate portion of th e calcaneus to the m ain tuberosity and an terior process. Intraoperative im agin g is useful to ensure restoration of radiographic landm arks and angles. Fixation is typically achieved with a low-profile locking plate designed for the lateral wall of the calcaneus. The use of bone graft is controversial. Non –weigh t-bearing is m aintained for 10 to 12 weeks un til fracture un ion , an d early ran ge of m otion is in itiated once the wound has safely healed. Complications include soft tissue breakdown, in fection, subtalar and calcaneocuboid arth ritis, m alun ion, ch ron ic regional pain syn drom e, an d sural n erve injury. Given th e m inim al am ount of soft tissue available, rotational or free flaps m ay be n ecessary for coverage if woun d breakdown occurs. Th is sh ould be perform ed quickly to avoid deep in fection and osteomyelitis. Arth ritis can develop rapidly especially if adequate reduction is n ot ach ieved. Patien ts with significant com m inution of the posterior facet or delam in ation of th e articular cartilage are can didates for ORIF with prim ary subtalar fusion . Th is avoids the potential complications of arthritis and m ay allow for earlier return to work. For an terior process fractures in volvin g m ore th an 25% of th e calcan eocuboid join t, O RIF is recom m en ded. Non displaced tuberosity avulsion fractures can be treated closed with im m obilization in plantarflexion for 3 weeks followed by an additional 3 to 6 weeks in neutral. Displaced pattern s require ORIF. Close m on itorin g of th e soft tissues is necessary.

Navicular Fractures Th e tarsal n avicular bon e is an importan t structure of th e m edial colum n involved in both hindfoot m otion through its articulation with the talus and m ain ten ance of the longitudin al arch via the cuneiform s. Navicular fractures are classified as dorsal lip, tuberosity, body, and stress fractures. AP, lateral, and m edial oblique radiographs of the foot are usually adequate for diagn osis. Dorsal lip fractures are th e m ost com m on , occurrin g from an eversion m echan ism , resulting in talonavicular join t capsule an d deltoid ligam en t avulsin g a fragm en t of bon e. Th e fracture fragm en t is best iden tified with a lateral radiograph . Th e differen tial diagn osis in cludes an accessory ossicle of the navicular and talus. The m ajority of cases are treated with a short-leg walking cast for 4 to 6 weeks. With sign ifican t articular surface in volvem en t, O RIF sh ould be perform ed. Persistent displacem en t can generate a painful prom inence and is treated with excision. Tuberosity fractures result from an eversion m ech an ism an d eccentric contraction of the posterior tibial tendon. Local tenderness is elicited, and there is pain on resisted

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in version . Displacem en t is often m in im al because of th e broad attach m en t of th e posterior tibial ten don . AP an d m edial oblique radiograph s best dem on strate th e fracture. If an accessory navicular is suspected, wh ich is present in 12% of th e population an d bilateral in 64% of cases, radiograph s of th e con tralateral foot can be obtain ed. Treatm en t for n on displaced or m in im ally displaced fractures is im m obilization for 4 to 6 weeks in a sh ort-leg cast. Fractures displaced 1 cm or m ore sh ould be open ed an d reduced to preclude dysfun ction of th e posterior tibial ten don . Sym ptom atic n on un ion s m ay be treated by excision of th e fragm en t, advan cem en t of th e ten don to th e rem ain in g tuberosity, an d im m obilization for 4 to 6 weeks. Proper function of the posterior tibial tendon is the m ost importan t factor in determ in in g appropriate treatm en t. Navicular body fractures can occur in isolation but frequently occur with other foot injuries. Typically, they in volve both th e talon avicular an d n avicular cun eiform join ts. Body fractures are classified on th e basis of th e location an d orien tation of th e fracture lin e. Type I fractures are tran sverse in th e coron al plan e with out associated an gulation of th e forefoot. Type II fractures are oblique, runnin g dorsolateral to plantar m edial. The forefoot is displaced m edially with a large dorsom edial fragm en t. Type III fractures h ave cen tral or lateral com m in ution with lateral displacem en t of th e forefoot. Atten tion sh ould be paid to associated fractures an d dislocation s of th e m idfoot an d m etatarsals on th e radiograph s. A CT is useful for defin in g the fracture pattern and determ ining the am ount of com m in ution of th e articular surface. Th e goal of surgery is to an atom ically reduce th e articular surface of all join ts an d restore len gth to th e m edial colum n . Option s for fixation in clude screws an d m in i-fragm en t plates for reducible pattern s, wh ereas tran sarticular fixation or temporary bridge platin g m ay be n ecessary for h igh ly com m in ution pattern s. weight-bearing should be delayed for 3 m onths. Stress fractures occur in the avascular central th ird of the n avicular bon e and are typically seen in youn g m ale athletes perform in g repetitive h igh -in ten sity activities. Clin ically, the pain is localized to the dorsolateral aspect and is worse with activity. Frequen tly, th e fracture is n ot visible on plain radiographs. Bone scan , CT, and MRI are useful to confirm diagn osis wh en radiograph s are n egative. Treatm en t of in complete stress fractures requires 6 to 8 weeks of cast im m obilization . Displaced fractures an d n on un ion s exh ibitin g sclerosis require ORIF with bon e graftin g. Chronic un treated con dition s m ay result in debilitatin g pain caused by talon avicular arthrosis, which m ay ultim ately require arth rodesis.

Cuboid Fractures Cuboid fractures are typically associated with other injuries of th e m idfoot an d rarely occur in isolation . Th e two com m on pattern s are the avulsion type and compression injuries to th e cuboid. Th e avulsion -type in jury results from

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an in version m ech an ism . A “fleck’’ sign m ay be visible on radiographs. These are treated with short-term im m obilization . Compression , or n utcracker, fractures of th e cuboid occur as the forefoot displaces laterally with a Lisfranc in jury. Th is results in loss of axial len gth of th e lateral colum n an d creates an asym m etrical flatfoot pattern . Th e goal of treatm en t is to restore th e articular surfaces, len gth of th e lateral colum n , an d kin em atics of th e foot. Len gth is restored by external fixation or plating. Bone graft m ay be necessary to fill defects of the cuboid. The foot is im m obilized in a sh ort-leg, n on –weigh t-bearin g cast for up to 12 weeks. Late arth rodesis m ay be n ecessary if arth rosis of the calcaneocuboid joint develops.

Lisfranc Injuries In juries to th e tarsom etatarsal join t, or Lisfran c join t, in clude a spectrum from subtle sprains to fran k dislocation s. Un fortun ately, even wh en appropriately diagn osed an d treated with an atom ic reduction of th e join t, fun ction al outcom es can be poor, especially with h igh -en ergy in juries. Th e tarsom etatarsal join t complex is composed of th e th ree cuneiform s, the cuboid, and the five m etatarsal bases. The bony arch itecture is sim ilar to th at of a Rom an arch in design and stability. The keystone of the arch is the second m etatarsal, wh ich h as a wedge-sh aped base recessed between th e m edial an d lateral cun eiform s. Th e stron g plan tar in terosseous ligam en ts an d tran sverse in term etatarsal ligam en ts furth er support th e stable bon e con figuration . Th e in term etatarsal ligam en ts con n ect th e four lesser m etatarsal; h owever, th ere is n o such ligam en t between th e first an d secon d m etatarsal. Th e Lisfran c ligam en t span s th e plan tar–lateral aspect of the m edial cun eiform to the m edial base of th e secon d m etatarsal an d fun ction s to resist lateral tran slation of th e lesser m etatarsals (Fig. 19.24). Th e first m etatarsal–m edial cun eiform join t is stabilized by th e join t capsule an d by th e in sertion s of th e an terior tibialis an d peron eus lon gus ten don s. Th e lack of ligam en tous support between th e first an d secon d m etatarsal ren ders it susceptible to injury and is the weak link of th e tarsom etatarsal join t complex. Successful treatm en t is m ost depen den t on restorin g an d m ain tain in g th is an atomy.

Classification A num ber of classification system s have been proposed; however, not a single classification system provides an algorith m for treatm en t or progn ostic value. Quen u an d Kuss described th ree types based on th e pattern of displacem en t of th e m etatarsals—isolated, h om olateral, an d divergen t (Fig. 19.25). In isolated type, on e or two of th e m etatarsals displaces relative to th e oth ers. Hom olateral refers to all of th e m etatarsals displacin g eith er m edially or laterally. In th e divergen t type, th e first ray is displaced m edially while the lesser ones laterally. It is probably m ost h elpful to divide th ese in juries in to purely ligam en tous an d th ose in -

Figure 19.24 The Lisfranc ligament spans from the medial cuneiform to the base of the second metatarsal. (Reproduced with permission from Johnson D, Pedowitz RA. Practical Orthopaedic Sports Medicine and Arthroscopy. Philadelphia, PA: Lippincott Williams & Wilkins, 2007.)

volving a fracture as these two patterns heal differently and sh ould poten tially be approach ed differently for treatm ent.

Mechanism of Injury Both direct an d in direct m ech an ism s h ave been described (Fig. 19.26). The direct m echan ism is a crush injury to the dorsum of th e foot, resultin g in plan tar displacem en t of the m etatarsals. High-energy traum a and heavy crush injuries produce sign ifican t in jury to th e soft tissue, vascular injuries, compartm ent syndrom es and open wounds. Axial an d rotational loading on a plantarflexed foot can injury th e Lisfranc joint in directly. This pattern is seen in m otor vehicle crashes, equestrian in juries, falls, and during sports participation . Th e m etatarsals are usually displaced laterally and dorsally. With abduction of the forefoot, the cuboid can be fractured. Presentation Patients with low-energy injuries usually complain of pain in th e m idfoot and inability to bear weight after a twisting injury to the foot. Crush m echanism s are m ore obvious, an d th ese patients m ay also have other injuries. Physical Examination Up to 20% of th ese injuries are m issed on initial evaluation because of th eir broad spectrum of presen tation . Gross deform ity of th e m idfoot m ay n ot be apparen t if there was spontaneous reduction. Tendern ess, ecchym osis, and swellin g over th e tarsom etatarsal join ts are typical. Pron ation -abduction stress m ay recreate th e pain an d deform ity. Incon gruity an d crepitus of the m idfoot is n oted on severely un stable in juries. Careful in spection of th e soft tissues an d a thorough neurovascular exam in ation is


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Figure 19.25 Quenu and Kuss classified Lisfranc injuries as homolateral, isolated, or divergent. (Reproduced with permission from Rockwood CA, Green DP, Bucholz RW. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

necessary. Signs and sym ptom s of compartm ent syndrom e sh ould be investigated.

Imaging AP, lateral, and 30-degree m edial oblique radiographs are obtain ed to evaluate the in jury. On the AP, the first m etatarsal should line up with the m edial cuneiform an d the m edial border of th e second m etatarsal base should line up with the m edial aspect of the m iddle cuneiform . An avulsion fracture from the base of the second m etatarsal, from the pull of the Lisfranc ligam ent, is diagnostic for the injury occurring in m ore than 90% of cases. On the oblique view, the lateral border of the third m etatarsal sh ould line up with th e lateral edge of the lateral cuneiform and the m edial aspect of the fourth m etatarsal should align with the m edial aspect of th e cuboid. On the lateral view, the dorsal borders of th e first an d secon d m etatarsals sh ould lin e up with th eir respective cun eiform s with out eviden ce of stepoff. Because th ese in juries m ay spon tan eously reduce, it is best to obtain weigh t-bearin g, sim ulated weigh t-bearin g, or stress views to iden tify in stability of th e tarsom etatarsal join t com plex if n on –weight-bearin g radiographs are norm al (Fig. 19.27). Comparison views or CT scans are helpful wh en th e in jury is subtle. Differential Diagnosis Th e differen tial diagn osis in cludes n avicular fracture, cuboid fracture, second m etatarsal base fracture, stress fracture, and rupture of the posterior tibialis tendon.

Treatment Th e m an agem en t of tarsom etatarsal join t in juries in volves obtain in g a stable, pain less plan tigrade foot by m ean s of anatom ic restoration of articular congruency. Treatm ent option s ran ge from closed reduction an d cast im m obilization for nondisplaced in juries to ORIF for displaced injuries. Given th at K-wire fixation frequen tly fails, th ese are best stabilized with screw fixation . All fracture-dislocation s sh ould be reduced an d im m obilized urgently to m inim ize th e risk of vascular an d soft tissue com prom ise. In cision s are m ade over the first an d third interm etatarsal spaces on th e dorsum of th e foot. Care sh ould be taken to m ain tain th e soft tissue bridge between . Reduction an d prelim inary fixation starts m edially and proceeds laterally. After con firm in g an atom ic reduction with appropriate im agin g, defin itive screw fixation follows. If th ere is in stability of th e fourth an d fifth tarsom etatarsal join ts, th ese sh ould be reduced an d h eld with K-wires (Fig. 19.28). Th e lateral side of th e foot is rath er m obile; th erefore, screw fixation is too rigid. If a nutcracker injury to the cuboid is presen t, restoration of th e lateral colum n len gth is n ecessary. An external fixator m ay be needed to m ain tain len gth of th e lateral colum n . Postoperatively, th e patien t is placed in a non –weigh t-bearing cast for 6 to 8 weeks, followed by progressive weigh t-bearin g in a cast for an addition al 4 to 6 weeks. If K-wires are used for the fourth and fifth tarsom etatarsal join ts, th ey should be rem oved at 8 weeks. Screws are rem oved 6 to 9 m onths after treatm en t. Com plication s in clude posttraum atic arth rosis, ch ron ic pain , m alunion, and deform ity. Secon dary arthrosis develops in

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21


A

Brake pedal

B C

Figure 19.26 Lisfranc injuries occur from axial loads to the foot during athletics (A), direct forces related to motor vehicle crashes (B), and axial loads due to a fall from height (C). (Reproduced with permission from Rockwood CA, Green DP, Bucholz RW. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

up to 70% of cases an d can be treated with m edial colum n arth rodesis. There is increasin g evidence that patien ts with purely ligam en tous in juries m ay ben efit from prim ary arth rodesis of the m edial colum n, because of the poor healin g poten tial of th e join t capsules an d ligam en ts. Given th e poten tial for improved outcom es, fusion should be considered for patien ts with th ese in juries.

Metatarsal Fractures Metatarsal fractures are th e m ost com m on fracture of th e foot and usually occur from a direct blow. For high-energy in juries such as th ose sustain ed in m otor veh icle crash es or by h eavy objects, in jury to th e soft tissue can be significant. AP, lateral, an d oblique radiographs are usually adequate for diagn osis an d treatm en t. Low-en ergy in juries with m inim al displacem en t are treated conservatively with

n on –weigh t-bearin g im m obilization for 3 to 4 weeks. Fractures with significant deform ity are best treated surgically with an atom ic reduction . Residual deform ity can result in chronic pain an d transfer m etatarsalgia. Distal fractures are m ore likely to displace due to lack of soft tissue attachm ents providin g stability to th e m etatarsal n eck an d h ead. ORIF with plate an d screw con structs are gen erally used for th e first m etatarsal, whereas K-wire fixation m ay be adequate for the lesser m etatarsals. For intraarticular fractures, the articular congruity should be restored. The goals of surgery are to restore the length, rotation, and angulation to ensure proper weigh t distribution am on g th e m etatarsals. Fractures of th e base of th e fifth m etatarsal are divided in to three zon es (Fig. 19.29). Zon e 1 fractures, the m ost com m on type, are avulsion fractures of th e peroneal brevis or lateral plan tar fascia caused by a plan tarflexion and inversion force. The fracture line travels into the tarsom etatarsal join t th rough cancellous bone, giving these

B

A Figure 19.27 Stress views are important in the evaluation of Lisfranc injuries. A normal-appearing

radiograph (A) taken without stress. A weight-bearing view of the same foot indicates gross instability (B). (Reproduced with permission from Rockwood CA, Green DP, Bucholz RW. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

Wire fixation

Screw fixation

B

A Figure 19.28 A typical construct for fixation of tarsometatarsal injuries. (Reproduced with permission from Rockwood CA, Green DP, Bucholz RW. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

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II

III

I Figure 19.29 Fractures of the base of the fifth metatarsal

are divided into three zones. Zone 1 fractures enter the tarsometatarsal articulation. Zone 2, or Jones, fractures enter the intermetatarsal joint. Zone 3 fractures occur distal to the diaphyseal– metaphyseal junction (Reproduced with permission from Rockwood CA, Green DP, Bucholz RW. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006.)

an excellen t ch an ce of h ealin g. Zon e 1 in juries are treated with a hard sole sh oe. Patien ts are allowed to bear weight as tolerated. Zon e 2 in juries, or Jon es fractures, occur th rough the interm etatarsal articulation. These fractures occur as a result of a n utcracker effect, in wh ich th e fifth m etatarsal is levered again st th e stable base of th e fourth m etatarsal. An avascular watersh ed zone between the n on overlapping in tram edullary an d extraosseous blood supply con tributes to th e h igh rate of n on un ion . Zon e 2 fractures are treated with a n on –weigh t-bearin g cast for 6 weeks followed by progressive weigh t-bearin g for an addition al 4 to 6 weeks un til un ion . Closed reduction an d percutan eous screw fixation usin g an in tram edullary screw is an option for h igh perform an ce ath letes an d th ose wh o n eed an early return to work. Delayed un ion s an d n on un ion s are treated with open bon e graftin g an d in tram edullary screw fixation . Th e postoperative regim en is sim ilar to acutely treated fractures. Zon e 3 fractures occur in th e distal m etaphyseal– diaphyseal jun ction an d are m ost com m on ly stress fractures. Acute fractures can be m an aged with a sh ort-leg non –weight-bearing cast for 6 weeks. In tram edullary screw fixation is reserved for ch ron ic fractures with m edullary sclerosis.

Sesamoid Fractures Fractures of th e sesam oid bon es occur as a result of direct traum a, fran k overuse, or avulsion in juries associated with hyperdorsiflexion (“turf toe’’). Disruption of the soft tissue surroun din g th e sesam oid com plex an d dislocation causing diastasis of the in tersesam oid ligam ent can occur. Radiographic evaluation includes AP, lateral, and axial views. It is importan t to distin guish fractures from a bipartite sesam oid, wh ich occur in approxim ately 25% of in dividuals. Wh ile fractures h ave irregular edges, a bipartite sesam oid h as sm ooth , sclerotic edges. Con tralateral radiographs or bone scan can assist in diagnosis. Acute fractures are treated with a cast or hard-soled shoe for 3 to 6 weeks. Pain associated with a n on un ion m ay require partial or total excision . Com plication s in clude h allux val-

gus and hallux varus with excision of the tibial an d fibular sesam oid bone, respectively. Transfer sesam oiditis of th e rem ain in g sesam oid is com m on . As an altern ative, bon e graftin g h as been successfully perform ed for sym ptom atic n onun ion s.

Phalangeal Fractures In jury to th e toes caused by stubbin g, axial loads, or a dropped object m ay result in join t dislocation or ph alangeal fracture. The proxim al phalanx of the fifth toe is the m ost com m only involved. Phalangeal fractures m ay either be displaced or nondisplaced, but there is frequen tly an gulation. The fracture sh ould be reduced and “buddytaped’’ to th e adjacen t toe, an d th e patien t sh ould wear a stiff-soled shoe or san dal. A fracture that extends into the join t sh ould be reduced an d stabilized with eith er K-wires or screw fixation . Sequela of th ese in juries in cludes join t instability, in congruence, and arthrosis.

ATRAUMATIC CONDITIONS OF THE FOOT AND ANKLE The Rheumatoid Foot Rheum atoid arthritis is a system ic autoim m une disease that com m only afflicts the foot, and its extent is related to the duration of system ic illn ess. Th e disease affects both th e syn ovial linin g of th e joints and the tendon s of the foot an d ankle. The forefoot and hindfoot are m ost com m only affected.

Pathophysiology and Classification Th e un derlyin g cause of rh eum atoid arth ritis is n ot en tirely un derstood. En viron m en tal, gen etic, an d even in fectious factors are th ough t to be in volved. Th e syn ovium becom es a target of th e im m un e system , resultin g in th e infiltration with inflam m atory cells an d synovial hyperplasia. The inflam ed syn ovium , referred to as pannus, ultim ately covers th e articular cartilage an d releases proteolytic en zym es, leading to the breakdown of cartilage and bone. The disease also affects the vascular system , which complicates surgical in terventions of th e foot and an kle. Neuropathy from en trapm en t, vasculitis, an d drug toxicity is com m on but is usually subclin ical. Clin ically, th e forefoot is th e m ost com m on ly affected area, followed by the hin dfoot. Ch ronic synovitis of the lesser MTP join ts leads to destruction of the articular cartilage, collateral ligam ents, and joint capsule. With disease progression , th e MTP join ts sublux dorsally as a result of groun d reaction forces. Th e destabilization of th e MTP joints pulls the plantar weight-bearing pad and plan tar plate distally, un coverin g th e m etatarsal h ead an d creatin g severe m etatarsalgia. Th e PIP an d DIP joints typically develop fixed flexion contractures due to im balance between


A

783

B Figure 19.30 A typical appearance of the rheumatoid forefoot. (Reproduced with permission from Kitaoka HB. The Foot and Ankle. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2002.)

the intrinsic and extrinsic m usculature. Painful callosities can develop over the dorsal aspects of these prom inent an d rigid joints. Hallux valgus, an an gular deform ity of the great toe at th e MTP join t, develops secon dary to abduction forces with am bulation and the loss of the secon d toe buttress from th e claw toe deform ity (Fig. 19.30). Th e h in dfoot falls in to valgus as destruction of th e articular cartilage, the ligam ents, the posterior tibial ten don , an d joint capsules of the subtalar and ankle join ts progresses. Depen din g on th e severity, th e deform ity can be flexible or fixed. An increasing valgus deform ity can result in calcaneofibular abutm ent and sinus tarsi impin gem en t. Midfoot degen eration is n ot as com m on as forefoot an d hin dfoot degeneration in rheum atoid arth ritis. Syn ovitis results in capsular atten uation an d join t subluxation with collapse of the longitudinal arch, and eventually a painful flatfoot. When a planovalgus foot deform ity develops with progressive failure of th e posterior tibial ten don , th e h igh ly m obile fourth and fifth m etatarsal cuboid joints are often spared. This results in forefoot abduction relative to th e hin dfoot, shorten ing of th e peroneal tendons, an d contracture of the gastrocnem ius–soleus complex.

Presentation Nearly 95% of patien ts with rh eum atoid arth ritis develop foot and ankle pain. It is th e initial m an ifestation of the disease in 15% of cases. Pain , swellin g, an d stiffn ess in the affected joints are early complaints. Pain in the ball of th e foot, m etatarsalgia, is due to th e prom in en ce of th e plan tar m etatarsal h eads. Sh oe wear leads to callosities an d pain over th e PIP join ts of th e lesser toes. Wh en th e h in dfoot is involved, patients m ost often complain of vague an kle pain or lateral pain secondary to peroneal ten don or fibular im pin gem en t. With progression of th e disease, th e ch aracteristic deform ities described earlier develop.

Physical Examination Th e physical exam in ation sh ould be system atic wh ile focusin g on th e m ost com m on ly in volved areas of th e ankle an d foot. The relative flexibility or rigidity of th e deform ity should be determ ined. The forefoot will typically sh ow claw toe deform ities of the lesser toes, with calluses un der th e m etatarsal h eads an d over th e PIP join ts. Eviden ce of a sym ptom atic h allux valgus deform ity is n oted. Th e an kle an d subtalar join ts are in spected to determ in e th e join t respon sible for a h in dfoot valgus deform ity. Laxity of th e deltoid ligam en t an d resultan t an kle in stability will often m asquerade as h in dfoot valgus. An AP weigh t-bearin g radiograph of th e an kle assists in m akin g th e distin ction . In th e m idfoot, m an ual stress m ay reveal hyperm obility of th e m idtarsal join ts in both th e sagittal an d tran sverse plan es an d detect th e presen ce of m ild warm th an d edem a. Discom fort is elicited with ran ge of m otion of th e cen tral th ree tarsom etatarsal join ts. Patien ts ten d to walk with a prolon ged stan ce ph ase, sh ort strides, an d a slow velocity to decrease stresses through a painful forefoot. Radiographic Findings weigh t-bearin g radiograph s are h elpful to docum en t th e progression of disease an d for surgical plan n in g. Juxtaarticular osteopenia, subchon dral cyst form ation, narrowing of th e join t space, bon e destruction , an d soft tissue swellin g are com m on findin gs on plain radiograph s. Radiographic changes usually precede clinical symptom s and the developm en t of gross deform ity. Th e severity of lesser digit MTP subluxation an d h allux valgus is noted. Th e cause of hindfoot valgus is assessed and attributed to either the ankle or subtalar join t. The m idfoot is in spected for subluxation of the first tarsom etatarsal join t. An in creased talar-first m etatarsal an gle is con sisten t with an acquired flatfoot an d forefoot abduction deform ity.

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Treatment Ph arm acological treatm en ts for rh eum atoid arth ritis in clude nonsteroidal an ti-inflam m atory drugs (NSAIDs), corticosteroids, and disease-m odifying antirh eum atic drugs (DMARDs). A rh eum atologist typically m an ages these m edications; however, it is important for th e orthopaedic surgeon to verify that patients receive appropriate treatm en t. In the forefoot, nonoperative m anagem ent seeks to decrease peak pressures on th e m etatarsal heads an d dorsal aspects of th e PIP join ts. Soft trilam in ate full-len gth orthotics and stiff-soled rocker sh oes offload the MTP joints an d m in im ize deform in g stresses. Th ese m easures relieve symptom s but do n ot restore norm al gait. Toe spacers, toe sleeves, and toe crests pad painful callosities, an d parin g of calluses provide sh ort-term pain relief. Physical th erapy aim ed at in creasin g m obility m ay also improve fun ction . When n on operative m an agem en t fails to provide relief, surgery is indicated. Operative in tervention aim s to reduce pain , im prove am bulatory status, sim plify sh oe-wear alteration s, an d en h an ce cosm esis. Surgery in volves th e stabilization of th e first ray, th e reduction of th e lesser MTP join ts, an d th e relocation of th e fat pads so as to provide a suitable weight-bearin g structure. It includes arth rodesis of the first MTP joint to provide perm anent stability to the m edial colum n alon g with PIP an d m etatarsal h ead resection al arth roplasty to align th e lesser toes. Complication s in clude problem s with woun d h ealin g, in fection , n on un ion , m alunion, recurrence of deform ities of the lesser toes, and recurrent m etatarsalgia. Non operative treatm en t of h in dfoot arth rosis in cludes the use of a soft University of California Biom echanics Laboratory (UCBL) orth osis with a rocker sole, a sm all h eel lift, an d m edial or lateral flarin g on th e outer sole to add stability. With early hindfoot collapse (increased valgus), an off-th e-sh elf ath letic an kle brace is h elpful for stabilization but an an kle–foot orthosis is necessary for advanced deform ities. Operative treatm en t of rh eum atic disorders of the hin dfoot includes arthrodesis of the subtalar joint, the talon avicular join t, an d th e calcan eocuboid join t (triple arth rodesis). A ten doach illes len gth en in g is n orm ally a part of th is procedure. Hin dfoot surgery, in th e presen ce of oth er m ajor in volvem en t of th e lower extrem ity, requires that the hip or knee be aligned initially so as to determ ine overall align m en t an d th us position th e h in dfoot properly. Th e goal of h in dfoot arth rodesis in a rh eum atoid patien t is to provide pain relief, improve fun ction an d align m en t, an d provide a stable platform for am bulation . Man agem en t of a rh eum atoid an kle arth rosis in cludes activity m odification , in term itten t corticosteroid in jection s, th e use of an an kle–foot orth osis and sh oe m odification s. Surgical option s in clude syn ovectomy, an kle arth rodesis, an d total an kle arth roplasty. Syn ovitis in th e an kle can be treated with an open or arth roscopic syn ovectomy. Irrigation procedures m ay decrease th e syn ovitic load on th e an kle join t but are temporizin g m easures at best.

Arth rodesis rem ain s th e on ly reliable an d durable procedure to treat a pain ful rh eum atoid an kle. In dication s in clude in tractable pain , sign ifican t deform ity, loss of ran ge of m otion , an d failed total arth roplasty. Tech n iques are sim ilar to those described for osteoarthritis of the an kle, but th ere is th e n eed for addition al fixation due to th e poor bon e quality. In th e presen ce of subtalar join t in volvem en t, as seen in cases of global talar avascular necrosis resulting from steroid use, a tibiotalar calcaneal arth rodesis m ay be required. It can be perform ed by in tern al fixation usin g can n ulated screws, specialized plates, or a retrograde in tram edullary rod. Total an kle arth roplasty h as h istorically been plagued by dism al long-term results; however, newer system s appear to yield better results. Its advan tage over arth rodesis in th e rh eum atoid patien t is th e m in im ization of stress tran sference to adjacen t joints as occurs following an isolated ankle fusion. In addition , m aintaining a m obile segm ent between th e MTP an d kn ee join ts avoids a severely stiff gait if th ere is bilateral involvem ent. Total ankle arthroplasty is con train dicated with severe coron al plan e deform ity. Man agem en t of m idfoot arth ritis con sists of arrestin g pain ful syn ovitis by m ean s of a sh ort-leg, weigh t-bearin g cast for 4 weeks followed by an orth osis with a m edial h eel wedge or, in advan ced cases, an an kle–foot orthosis. Stretchin g the Ach illes tendon helps relieve m idfoot stresses. Cortison e in jections are norm ally lim ited to the first tarsom etatarsal joint in conjunction with a short period of im m obilization . Surgery is reserved for patien ts with greater fun ction al dem an ds wh o can n ot tolerate bracing. The technique involves stabilizing th e m edial arch with arth rodesis. Typically, th e first, secon d, an d th ird tarsom etatarsal join ts are fused; rarely, th e fourth and fifth m etatarsal cuboid joints are included.

The Diabetic Foot Diabetes m ellitus is a devastatin g disease causin g m ultiple problem s in various organ system s th rough out th e body. Manifestation in the foot is com m on and can lead to serious con sequen ces. It is estim ated that 20% of diabetic patients h ave at least on e serious foot in fection durin g their lifetim e. Prevention of ulceration an d infection is important. However, on ce these occur, treatm en t m ust be aggressive.

Pathophysiology and Classification Diabetes m ellitus affects th e periph eral n erves an d th e vascular system , placin g patients at risk for ulcers, infections, and potentially amputation. Diabetic neuropathy is the m ost com m on foot and an kle m anifestation of the disease affectin g sen sory, m otor, an d auton om ic n erves. Light-touch and proprioceptive sen sory neuropathy typically occur first, progressing from distal to proxim al in a stocking and glove distribution, an d placing patients at risk for ulceration . Wh ile diabetic patien ts ten d to h ave a loss of sensation, th ey can also suffer from neuropathic


paresth esias, wh ich presen t as con tact hypersen sitivity, burn in g pain , an d ach in g. Th is m ay be treated with gabapentin . Motor changes can lead to an im balance between th e in trinsic and extrinsic m uscles of th e foot and the developm ent of claw toes. In addition equinus contracture is com m on. Together these deform ities produce areas of high stress under the m etatarsal heads and the dorsal aspect of th e PIP join ts with sh oe wear. With th e loss of autonom ic control of blood vessels, sweat glands, an d lubricating glands, the skin becom es dry and less pliable. With repetitive traum a the skin can fissure providing access for infection . Arthrosclerosis affects both large and sm all vessels, resulting in poor circulation , especially in th e feet. Most com m only the anterior tibialis, posterior tibialis, and peron eal arteries are affected just below th e trifurcation of th e popliteal artery. Lack of appropriate blood flow lim its h ealing potential of ulcers and infection. Foot ulcers are classified accordin g to th e system described by Wagner. Grade 0 lesions still h ave intact skin . Grade 1 lesion s are superficial ulcers. Grade 2 lesion s are deep with full-th ickn ess ulceration s. Grade 3 sign ifies th e developm en t of an abscess or osteom yelitis. Forefoot gan gren e is con sidered grade 4. Exten sive gan gren e is con sidered grade 5.

Presentation Diabetic patien ts are often un aware of th e sen sory an d vascular changes occurring in their feet placing them at risk for areas of breakdown and infection. Patien ts can experience neuropathic symptom s such as burning, deep ach es, and hypersen sitivity. However, even with th ese sym ptom s, th ey often lack protective sen sation . Patien ts m ay also presen t for evaluation of a worsen ing foot deform ity. Physical Examination Routine foot exam in ations are essential for diabetic patients. While a yearly comprehensive exam in ation by a physician is recom m en ded, patien ts sh ould be proactive in their own care, inspecting their feet on a regular basis for callosities an d areas of skin breakdown. Light touch, pin -prick, two-poin t discrim in ation , an d proprioception sh ould be evaluated. Most typically, the sensation loss follows a stocking and glove distribution. Sem m es–Wein stein m on ofilam ent testing is helpful to determ ine a patien t’s threshold of sensation , and the ability to feel a 5.07 m on ofilam ent indicates protective sensation . Chronic vascular in sufficiency can m anifest as hair loss and thin, sh iny skin. Th e presence or absence of the dorsalis pedis an d posterior tibial pulses sh ould be n oted. Diabetic patien ts often presen t for th e evaluation of a red, swollen foot, an d it is imperative to distin guish in fection from Charcot arthropathy of the foot. O n physical exam in ation , th e lim b sh ould be elevated above th e level of th e h eart. Any eryth em a an d swellin g related to Ch arcot

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arth ropathy will resolve, wh ereas it often does n ot wh en caused by infection. All deform ities of th e foot an d associated areas of plan tar prom in en ce (rocker-bottom deform ity) sh ould be evaluated an d n oted, as th ese m ay require preven tative treatm en t to avoid future skin breakdown .

Radiographic Findings Standard radiographs of the foot and ankle should be obtain ed if th ere is suspicion of traum a, Ch arcot arth ropathy, or osteomyelitis. Special Tests If th e diagn osis of in fection is in question , MRI is h elpful for establish ing the diagn osis, determ ining th e exten t of disease, an d distin guish in g it from Ch arcot arth ropathy. Tech n etium -99m an d in dium -111 –labeled leukocyte scan s are altern atives but are used less frequently with the widespread availability an d speed of MRI. Vascular evaluations are important to determ ine th e h ealin g potential of chron ic ulcers an d in fection s. Th e arterial pressure at differen t levels in th e leg can be m easured with Doppler ultrasoun d. Toe pressures greater than 45 m m Hg are th ough t to be n ecessary for h ealin g. Tran scutan eous oxygen m easurem en t is th e m ost accurate m easure of h ealin g poten tial. A level greater th an 30 m m Hg in dicates adequate circulation for h ealin g. Treatment Ideally th e treatm en t of th e diabetic foot sh ould focus on preven tion of ulcers an d in fection . Tigh t glycem ic con trol is an essential. The orthopaedist should always inquire how well patien ts are m an agin g th eir glucose levels an d en sure physician s are overseeing their m edication s. Patients sh ould in spect their feet daily and keep their skin well m oisturized. Areas of pressure should be relieved with shoe m odifications and the use of inserts. Extradepth shoes with a wide toe box are recom m ended. Rigid insoles should be avoided as th ese can h asten skin breakdown . Orth otics an d bracin g m ay h elp un load areas of h igh pressure, especially wh en deform ity is presen t. Surgery m ay be n ecessary to address bone deform ities causing areas of h igh pressure. On ce ulceration occurs, early and aggressive treatm ent m ust be initiated to prevent a deep infection . Necrotic tissue and areas of hyperkeratosis should be debrided, and local woun d care is essen tial. If th ere is n o eviden ce of in fection , patien ts are treated with total con tact castin g to un load th e area of breakdown to allow healing. Casts are placed with little padding to allow appropriate m olding and, therefore, m ust be placed by an individual experienced in their application . Un fortun ately, it is n ecessary to ch an ge th em frequen tly to m on itor h ealin g an d en sure th e correct fit of th e cast. In fection s require a com bin ation of surgery an d an tibiotic treatm en t. Th e vascular workup is critical to operative plan n in g to assess h ealin g poten tial. Serial debridem en ts

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are perform ed un til th e in fection is con trolled. Diabetic foot in fections are m ost often polym icrobial and involve gram -n egative organ ism s. Staphylococcus aureus is th e m ost com m only found organ ism , followed by Streptococcus, Enterococcus, Proteus mirabilis, Staphylococcus epidermidis, Peptostreptococcus, diphtheroids, and Pseudomonas aeruginosa. Unfortunately, m any patien ts ultim ately require amputation to con trol th e in fection , especially in th e settin g of in adequate tissue perfusion. Th ere are a num ber of amputation option s depen din g on th e exten t of in fection , h ealin g poten tial, an d quality of th e soft tissue. Th e sam e prin ciples apply to all am putation s—resection s th rough viable bon e outside th e zon e of soft tissue in fection an d with a ten sion -free woun d closure. Th e m ost com m on amputation s are digital, ray, tran sm etatarsal, an d below-kn ee am putation s. Patien ts m ust often decide between lim b salvage requiring m ultiple surgeries and amputation , which often provides a faster recovery an d a superior fun ction al result.

Charcot Arthropathy Ch arcot, or n europath ic, arth ropathy is a progressive destruction of joints, resulting in deform ity, ulceration, and poten tially am putation . Wh ile un derlyin g causes in clude syrin gomyelia, myelom enin gocele, alcoholism , syphilis, heavy m etal in toxication , con genital in sensitivity to pain , an d leprosy, th e m ost com m on cause in th e Un ited States is diabetes m ellitus.

Pathophysiology and Classification While m ultiple th eories exist to explain Charcot arth ropathy, th e com m on clinical fin dings are loss of proprioception an d vasom otor in stability. Min or repetitive traum a is not perceived by patients and th erefore not treated, resultin g in join t in stability, dislocation s, osteophyte form ation an d subch on dral fracture. In addition , th ere is a loss of auton om ic con trol, leadin g to a local hyperem ia of bon e an d relative osteopen ia. Th e exact in ciden ce of arth ropathy am on g diabetic patients is unknown , but the incidence is approxim ately 3%, with 6% to 40% of patien ts bein g affected bilaterally. Eichenholtz developed the classic classification system of Ch arcot arth ropathy. Stage I, or th e fragm en tation stage, is th e acute ph ase of th e disease process ch aracterized by subch ondral fragm entation , periarticular fracture, subluxation , an d dislocation . Stage II, or th e coalescen ce stage, is the beginn ing of the reparative process. Th is is best identified with serial im agin g—th e resorption of bon e debris, the form ation of new bone, an d sclerosis of bones. Stage III, or th e con solidation ph ase, is a period of rem odelin g an d h ealin g. Deform ity an d th e an kylosis of join ts m ay be th e en d result of th e Ch arcot process. Auth ors subsequen tly added a Stage 0, or in flam m atory stage. Radiograph s are n orm al; h owever, MRI an d bon e scan studies sh ow ch an ges. Th is stage m ay last up to 1 year before stage I ch an ges occur.

Th e m idfoot is affected in approxim ately 60% to 70% of cases, with th e m ost severe deform ity occurrin g at th e tarsom etatarsal articulation s. Th e an kle an d subtalar join ts accoun t for approxim ately 30% of cases.

Presentation Patients with stage 0 and I disease present with erythem a, swellin g, hyperem ia, and warm th. Th ese stages are com m on ly confused with infection. Fevers are not typical with Ch arcot an d support th e diagn osis of in fection wh en presen t. Th e swellin g m ay be severe en ough th at ordin ary sh oe wear is difficult. In stage II, th e symptom s of erythem a, swellin g, an d warm th dim in ish, and by stage III, these usually resolve. Even th ough m any patients have sign ifican t neuropathy, up to 75% h ave discom fort in th e foot an d ankle associated with this pathology. Only approxim ately 20% recall a traum atic event before developin g the sym ptom s related to Charcot. Physical Examination As noted earlier, patients in the early stage have erythem a, swellin g, an d warm th of the foot and ankle. The swelling an d erythem a related to Ch arcot often respon d to elevation above the level of th e heart as opposed to infection, wh ich does n ot. Patien ts typically exh ibit a den se n europathy. Good vascular perfusion m ay be present. Th e lim b sh ould be th oroughly in spected for ulceration and areas of skin breakdown . Radiographic Findings Radiograph s of th e foot an d an kle sh ould be obtain ed on all diabetic patien ts presenting with a red, swollen foot. First, radiograph s m ay aid in rulin g out osteomyelitis. Secon d, th e radiograph s h elp to determ in e th e stage of th e disease process an d th e appropriate treatm en t. Th e radiograph ic fin din gs for each stage h ave been discussed earlier. Third, characterizing the deform ity is necessary to plan surgical intervention . Ideally these radiographs should be weigh t-bearin g to iden tify subtle in stability pattern s. Special Tests MRI is becom ing m ore popular, especially in diagnosing early stages of disease. Stress reaction s an d bon e m arrow edem a are eviden t in th e periarticular an d subch on dral region s of m ultiple bon es. Th ese fin din gs differ from osteomyelitis, wh ich m ost often is diffuse with in on e bon e. Bon e scan s can also be used, but th ey h ave low specificity. Th ey are m ore useful to rule out osteom yelitis wh en n egative. Differential Diagnosis Clearly, it is m ost important to distinguish Charcot arthropathy from osteomyelitis in its early stages. Patien ts with in fection often h ave fevers, open woun ds, hyperglycem ia above th eir norm al blood sugar levels, nondepen dan t rubor, an d associated MRI fin din gs. Ch arcot can also be m isdiagnosed as gout, rheum atoid arthritis, ankle


sprain, an d deep venous throm bosis. A th orough history an d physical exam in ation in conjunction with appropriate im aging usually resolves any question in diagnosis.

Treatment Th e treatm en t goal is to establish a stable, plan tigrade foot with out deform ity. Treatm en ts vary depen din g on th e stage of disease, th e presen ce of open woun ds, an d th e join ts affected. For patients who presen t early in th e disease course, nonoperative m anagem en t should be attempted. Total con tact castin g is in itiated after a few days of elevation to decrease the swelling. Total contact casting allows for the even distribution of th e forces across th e plan tar aspect of th e foot. Every 2 to 4 weeks, the cast is chan ged until the process has entered the coalescence phase when the foot is no longer warm , erythem atous, and swollen and radiograph s sh ow sign s of stability. Approxim ately 4 m on th s of casting is expected; afterwards, patients are transition ed to custom -m ade shoes with orthotics. Historically, patients were told to rem ain n on –weigh t-bearin g; h owever, som e specialists n ow allow m odified weight-bearin g. There is no defin itive eviden ce th at n on –weight-bearing increases the risk of developin g Ch arcot in th e oth er lim b due to th e in creases in forces. Deep ulcers complicate the n onoperative m anagem ent of Charcot arthropathy because of th e risk of osteomyelitis. Wh en associated with in fection , ulcers require debridem en t an d eviden ce of local con trol prior to initiation of total contact castin g. Altern atives to total contact castin g in clude rem ovable casts an d Ch arcot restrain t orth otic walker (CROW) devices. Th ese fun ction in a m an ner sim ilar to total con tact casts by distributing forces on the plantar aspect of the foot. Their advantages over total con tact castin gs is that soft tissue can be m ore closely m on itored and they do not require specialized trainin g in th eir application. With sign ifican t deform ity, recurren t ulceration , an d join t in stability surgical in terven tion m ay be n ecessary for the treatm ent of Charcot arthropathy an d its residual deform ity. Tradition ally, surgery was not perform ed during the fragm entation phase of the disease because of the risk of n on un ion , m alun ion , an d in fection . It was typically delayed un til the consolidation ph ase. More recently, this h as been question ed, especially with tech n iques usin g external fixation. There is no consen sus on the optim al tim ing of surgical in terven tion . Surgical in terven tion s ran ge from exostectomy to com plex recon struction s an d arth rodesis. Im m obilization is con tin ued un til th e eryth em a, swellin g, an d warm th resolve. Patients are then placed into custom m olded orthotics.

Achilles Tendon Pathology Th e term s referrin g to ten don con dition s can be con fusing and are often used inaccurately. Even th ough one m ay be able to distinguish ten dinosis versus tendonitis based on h istory an d physical exam in ation , it is best to use ten din opathy wh en m akin g a clin ical diagn osis.

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Ten din opathy is a broad term th at en com passes both ten din itis an d ten din osis, wh ich are con firm ed with path ological evaluation . Ten din itis h as an acute in flam m atory compon ent, whereas tendin osis is m ore of a chronic degenerative n oninflam m atory condition. Path ology of th e Ach illes ten don m ust be divided in to in sertion al an d n on in sertion al as well as acute an d ch ron ic. Non in sertion al path ology occurs approxim ately 4 to 6 cm proxim al to th e in sertion site in an area of relative poor vascularity. Symptom s can result from acute in flam m ation of th e paraten on (paraten on itis) or from a m ore ch ron ic degen eration of th e ten don itself (ten din osis). In sertion al path ology causes posterior h eel pain an d is com m on ly associated with retrocalcan eal bursitis an d a Haglun d deform ity.

Pathophysiology and Classification Tendinosis is the result of the repetitive stress of lengthening and shortening of the Achilles tendon during am bulation. Without appropriate rest to allow for norm al tendon repair, con tin ued overuse can result in th e degen eration of th e collagen structure of th e ten don 4 to 6 cm proxim al to th e insertion. Th is form of non insertion al Achilles ten din opathy is typically seen in lon g-distan ce run n ers. Collagen is not produced norm ally, neovascularization occurs, fibroblasts proliferate, an d m ucoid m aterial is deposited, wh ich m an ifests as a palpable n odule an d th icken ing of the tendon. The pathological tendon h as less tensile stren gth and elasticity. Tendin osis typically lacks an inflam m atory component. In flam m atory con dition s of th e paraten on an d ten don can occur at th e in sertion an d proxim ally. In sertion al path ology is m ost com m on ly related to retrocalcan eal bursitis an d irritation of th e Achilles ten don itself. The retrocalcan eal bursa is located between th e posterior an gle of th e os calcis an d th e Ach illes ten don . Th is can becom e in flam ed and thicken ed, often due to sh oe wear. An en larged posterosuperior calcan eal process, com m on ly referred to as a Haglund deformity, predisposes a person to retrocalcaneal bursitis. Calcification of th e in sertion site can also develop with ch ron ic in flam m ation . Presentation Non in sertion al Ach illes ten din osis occurs m ost com m on ly in runn ers with a history of altered training or shoe wear. Pain is presen t alon g th e Ach illes ten don approxim ately 4 to 6 cm proxim al to its in sertion. The pain is aggravated by activity and relieved with rest. Uphill runn ing or walking is especially pain ful. In sertion al ten din itis an d retrocalcan eal bursitis com m only presen ts in m iddle-aged to elderly wom en with posterior h eel pain . Examination A ten der fusiform n odule is presen t with in th e substan ce of th e Ach illes with ten din osis. With periten din itis, th e

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m ass is typically m obile an d is associated with com m on signs of in flam m ation, in cludin g pain, stiffn ess, swellin g, an d diffuse ten dern ess. Ten dern ess m edial an d lateral to the Ach illes tendon at the insertion site is typical of retrocalcaneal bursitis. With in sertional inflam m ation of the Ach illes, there is tenderness directly at the point of posterior in sertion . In both in sertion al an d n on in sertion al path ology, th ere is n o loss in con tin uity of th e Ach illes ten don , so patien ts can perform a h eel rise test, an d th e Th ompson test is n egative. Con tracture of th e Ach illes is usually a con stan t fin din g in both form s of ten din opathy.

Imaging Studies Stan dard radiograph s are n ot usually n ecessary for n on in sertion al path ology but m ay sh ow calcification s related to th e ten din osis. More distally, radiograph s can sh ow a Haglund deform ity or calcification of the tendon . MRI is m ore useful to evaluate th e un derlyin g path ology both proxim ally an d at th e in sertion site. Th is can easily distin guish between periten din itis, th icken in g of th e outer sh eath , tendinosis, and in traten din ous degeneration . Differential Diagnosis System ic disorders such as gout an d spon dyloarth ropath ies sh ould be ruled out. Posterior in sertion al h eel pain m ust also be distin guish ed from plan tar fasciitis an d calcan eal stress fractures. Reiter syndrom e m ay present with in sertion al Ach illes ten don pain an d retrocalcan eal bursitis. Th ere is also a kn own association of Ach illes ten don path ology an d fluoroquin olon e use. Treatment Th e goal of treatm en t for n on in sertion al Ach illes ten dinosis is to reverse th e degenerative process an d allow n orm al h ealin g of th e ten don . Non operative m an agem en t is recom m en ded in itially; h owever, it ten ds to be less effective when the condition is m ore chronic. Treatm en t typically in cludes NSAIDs, rest, sh oe m odification , an d physical th erapy. In correct th erapy regim en s such as con centric strengthening can often worsen symptom s. Eccentric stren gth en in g is recom m en ded. A h eel lift an d th e use of open -backed sh oes m ay be h elpful in reducin g sym ptom s durin g daily activities. Altern ative m odalities in cludin g ultrasoun d an d extracorporeal sh ock wave th erapy h ave sh own good results. Use of local steroid injection s is n ot recom m en ded because of th e poten tial for ten don rupture an d subcutan eous atrophy. If nonoperative m anagem ent h as failed to provide relief of sym ptom s after 4 to 6 m on th s, surgery m ay be in dicated. Th e ten don is split lon gitudin ally an d all path ological tissue is excised. The rem aining ten don is repaired side-toside. In cases of severe, exten sive tendin osis, augm en tation with the adjacent FHL ten don is recom m ended. The treatm ent of isolated retrocalcan eal bursitis is n onoperative. Heel lifts h elp to m ove th e bursal prom in en ce

forward an d away for the Achilles tendon. NSAIDs and occasion al im m obilization can be ben eficial. Wh en a Haglund deform ity is present, surgical interven tion m ay be required to rem ove th e posterosuperior process of th e calcan eus. Atten tion is also directed toward debridem en t and repair of the Achilles tendon insertion and resection of any calcific deposition or osteophytes.

Tarsal Tunnel Syndrome En trapm en t of th e posterior tibial n erve with in th e fibroosseus tun n el posterior an d distal to th e m edial m alleolus is referred to as tarsal tunnel syndrome. The tarsal tunnel is the distal extension of the deep fascia of the posterior com partm en t, form ed by m edially by th e talus, susten taculum tali, an d calcan eus, an d laterally by th e flexor retin aculum (laciniate ligam ent). Th e posterior tibialis, FDL, an d the FHL ten don s traverse th e can al with in in dividual sh eath s, with th e posterior tibial n erve an d artery lyin g between sh eath s.

Pathophysiology and Classification Compression the posterior tibial nerve can occur from with in or outside th e tun n el. Space occupyin g lesion s such as varicosities, lipom as, ganglia, perin eural fibrosis, bony exostoses, flexor retin aculum hypertrophy, rh eum atoid syn ovitis, an d an om alous m uscles m ay create compression . Foot deform ities such as hindfoot varus with forefoot pronation and hindfoot valgus with forefoot abduction are associated with th is con dition . Traum a in cluding displaced fractures of the distal tibial and hindfoot as well as an kle sprain s h ave led to tarsal tun n el sym ptom s. In reality, an etiology is iden tifiable in on ly approxim ately 50% of cases. Presentation Patients characteristically complain of burning pain in the arch, vague n um bness in the toes, night pain, and pain that is accentuated by am bulation. Extrem es of dorsiflexion place th e n erve un der ten sion an d m ay exacerbate sym ptom s. Pain m ay radiate proxim ally in to th e m idcalf. Motor deficits an d in trin sic paralysis are late fin din gs. Som e patients report a m inor traum a precedin g the symptom s. Physical Examination Physical fin din gs in approxim ately h alf of patien ts in clude a positive percussion test (Tin el sign ) over th e posterior tibial nerve reproducing the symptom s. Two-point discrim in ation on the plan tar aspect of th e foot sh ould be tested, sin ce th is is th e first sensory abnorm ality seen in the condition . Motor weakn ess is un com m on but can affect th e in trin sic toe flexors, the abductor hallucis, and the abductor digiti m in i. If th e con dition is caused by an accessory m uscle or hypertrophy of th e abductor hallucis longus, fulln ess in the area m ay be appreciable.


Given th e association with certain deform ities, th e position of the hindfoot sh ould be noted.

Radiographic Findings Wh ile th e overall yield of radiograph s m ay be low, th ese help to evaluate the an atomy of th e foot an d rule out certain space-occupyin g lesion s such as exostoses, accessory ossicles, an d fractures. Special Tests Electromyograph ic n erve con duction studies are h elpful in ruling out lum bar disk disease as the source of sym ptom s. Diagn ostic fin din gs for m edial plan tar n erve in volvem en t include term inal latency in the abductor hallucis of m ore than 6.32 m illiseconds. Sim ilarly, a prolonged latency of m ore than 7 m illisecon ds in th e abductor digiti m ini is consistent with lateral plantar nerve involvem ent. Sensory laten cies are th e m ost sen sitive tests because th ese are th e first fibers affected. MRI is useful to delin eate space-occupyin g lesions. Differential Diagnosis Radicular lum bar path ology, plan tar fasciitis, periph eral neuropathy, stress fractures, an d in flam m atory arth ropath ies can presen t with sim ilar sym ptom s. Treatment Treatm ent includes NSAIDs to control pain and orthotics to con trol hindfoot valgus and decrease the ten sion across the tun nel. Cortisone injections to decrease inflam m ation an d bracin g to rest th e n erve m ay be h elpful. Surgery in volves decom pressin g from th e proxim al aspect of th e flexor retinaculum to th e bifurcation of the tibial n erve. This sh ould be exten ded to release th e superficial calcan eal bran ch of the tibial nerve and trace the plantar branches distally through the abductor hallucis m uscle. Resection of any space-occupying lesion should be perform ed, in cluding an om alous m uscles. Internal neurolysis is indicated if there is evidence of n erve fibrosis. Good results are expected in up to 95% of patien ts wh en a space-occupyin g lesion is iden tified. When there is not, approxim ately 75% of patients improve after tarsal tun nel release.

Peroneal Tendon Pathology Th e peron eal ten don complex con sists of th e peron eus brevis an d longus, which course behind the lateral m alleolus. Above the level of th e an kle joint, the two tendons travel in a com m on syn ovial sheath. The peroneus longus lays posterolateral to th e peron eus brevis as th ey pass beh in d the lateral m alleolus in th e retrom alleolar groove. The superior retin acular ligam en t, th e prim ary lateral restrain t to dislocation of th e ten don s, form s th e roof of th e groove. More distally, the sh eath diverges such that each tendon travels in its own sheath separated by the peroneal tubercle as th ey pass under the inferior peroneal retin aculum

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2 cm distal to th e tip of the fibula. The peron eus brevis then inserts on the base of the fifth m etatarsal while th e peron eus lon gus travels un der th e cuboid to in sert on to the base of the first m etatarsal. A sm all pisiform bone is contained within the peroneus longus as it passes around the cuboid. This flat disc can appear as an avulsion fracture on oblique foot radiograph s. Conditions affecting th e peroneal tendon complex fall into three categories—tendonitis/tenosynovitis, tendon tears/ ruptures, an d subluxation / dislocation . Th ese ten don path ologies are un com m on an d un fortun ately often m issed.

Pathophysiology and Classification Tendinitis/ tenosyn ovitis is com m only related to an increase in repetitive activity such as running after a period of in activity and is caused by a m echan ical irritation. Varus hindfoot alignm ent is a risk factor for developing tendinitis. In version in juries, ch ron ic ten osyn ovitis, an kle sprain s, an kle fractures, chronic ankle instability, and stenosis of the retrofibular groove can all cause ruptures an d tears of th e peron eal ten don s. Peron eal ten don subluxation or dislocation is usually a sports-related injury. An inversion in jury to a dorsiflexed foot with eccentric loading is the m ost com m on m ech anism for peroneal tendon subluxation . Presentation Lateral ankle pain and swelling are the m ost com m on presenting com plain ts. Wh en patien ts present acutely, an isolated injury is often identifiable. In chronic in juries with a h istory of m ultiple an kle sprain s, th ere are often associated pathologies present. Peroneal tendon pathology com m only accompanies lateral an kle in stability. Examination Th e an atomy an d align m en t of th e foot sh ould be in spected given the association between a cavovarus foot and peron eal ten don path ology. Swellin g an d ten dern ess m ay be appreciable along the peroneal tendons. Passive inversion of th e h in dfoot an d resisted eversion with dorsiflexion can reproduce peron eal ten don pain . Eversion stren gth is n ot usually affected. Sn appin g of th e ten don s beh in d th e fibula can be associated with ten don subluxation or fran k in stability. It is im portan t to test th e stability of th e an kle ligam ents and rule out oth er causes of lateral ankle pain, such as an osteochon dral defect. Radiographs AP an d lateral radiograph s of th e foot an d an kle sh ould be obtain ed to evaluate for os peron eum , fibular im pin gem ent, and arthrosis. Avulsion fractures of th e calcaneus and base of the fifth m etatarsal can be ruled out. A fleck sign m ay be visible on an AP im age, which is a sm all piece of bon e avulsed off th e fibula by th e superior peron eal retin aculum . MRI is th e stan dard for evaluatin g path ology of th e ten don s. Ultrasoun d is poten tially a relatively

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in expen sive but h igh ly sen sitive an d specific altern ative if perform ed by appropriately train ed tech n ician s.

Treatment First-lin e treatm en t of peron eal complex path ology is n on operative an d in cludes activity m odification , brief im m obilization , an d NSAIDs. After th e acute ph ase, physical therapy can be initiated. Wh en this fails and surgery is plan n ed, it is essen tial to address th e un derlyin g con dition an d an atom ic variation respon sible. Th e m ost im portan t an d probably m ost com m on is lateral an kle in stability. Th is m ust be addressed to improve th e ch an ces of successful treatm ent. Ten din itis an d ten osyn ovitis are treated with syn ovectomy an d debridem en t. Ten don tears less th an 50% of th e cross-sectional area are treated with debridem ent and tubularization . If th e tear is complete, a ten odesis is perform ed between th e peron eus lon gus an d peron eus brevis. For a tear or rupture of both ten don s, a ten don tran sfer or ten don graft m ay be n ecessary. Tran sfer option s in clude FDL to peron eus brevis an d plan taris to peron eus lon gus. Surgical treatm en t option s for peroneal tendon subluxation or dislocation in clude an atom ic repair of th e superior retin aculum , tissue tran sfers for recon struction , groove-deepen in g procedures, an d ten don reroutin g un der th e CFL.

Acquired Adult Flatfoot Deformity Dysfun ction of th e posterior tibial ten don can ran ge from m ild ten din itis to complete rupture an d an asym m etrical flatfoot deform ity. Underlying causes include traum a, in flam m atory arth ropath ies, an d attrition al degen erative conditions.

Pathophysiology and Classification Th e posterior tibial ten don is in volved with m ain ten an ce of the lon gitudinal arch and bringing the hin dfoot into varus for push-off. Wh en the posterior tibial m uscle contracts, it provides a varus force to th e h in dfoot, causin g tran sverse tarsal join t to lock an d creatin g a rigid foot to tran sm it th e force of the gastrocsoleus complex. With attenuation an d degen eration , th e h in dfoot falls in to valgus, th e forefoot in to m ore abduction , an d effective push -off is n ot possible. Wh ile posterior tibial ten don dysfun ction in acquired adult flatfoot deform ity is usually th e cause of pain an d swelling, it is n ot the only pathological structure in th e disease process. With h in dfoot valgus an d abduction of th e forefoot, th e Achilles tendon and deltoid ligam ent also becom e dysfunction al over tim e. The classification system proposed by John son an d m odified by Meyerson focuses on th e flexibility of th e flatfoot deform ity. Stage I describes pain and swelling with m in or weakn ess of th e posterior tibialis m uscle an d th e absen ce of deform ity. Stage II in volves posterior tibial ten don disruption with m edial colum n collapse an d a flexible flatfoot deform ity. Stage III is reserved for a rigid flatfoot

and potentially arthrosis. Asym m etry of the tibiotalar join t associated with a rigid flatfoot is con sidered stage IV.

Presentation Patients present with pain , swelling, and fullness localized to th e posterior m edial h in dfoot an d n ote difficulty with am bulation. Only approxim ately 50% of patients report a traum atic even t. With progressive deterioration of the tendon an d in com peten t fun ction , a progressive asym m etrical flatfoot deform ity develops. Late symptom s include progression of deform ity, difficulty with sh oe wear, an d lateral calcaneal-fibular impingem ent. Examination Clinical exam ination in the early stages reveals tender, boggy edem a at th e level of th e m edial m alleolus, a secon dary Ach illes con tracture, an d weakn ess of isolated posterior tibial ten don stren gth testin g (resisted in version with the foot in a plantarflexed and abducted in a non –weigh tbearin g position ). Patien ts are un able to perform a sin gleleg heel rise and often there is no inversion of th e hindfoot on double-stance toe rise (Fig. 19.31). Flexibility of the subtalar and transverse tarsal joint is evaluated, as this alters treatm ent. The Jack test consists of passively dorsiflexing the h allux, which results in restoration of the m edial longitudinal arch in flexible con ditions. With advanced forefoot abduction an d collapse, th e “too m any toes’’ sign occurs wh en observin g a patien t from beh in d in restin g stan ce (Fig. 19.32). With advanced collapse, th ere is eviden ce of loss of m edial lon gitudin al arch , an d th ere are varyin g degrees of rigidity. Because of the association with Achilles tendon con tracture, the range of th e m otion of the an kle sh ould be noted. Wh en doin g so, th e talonavicular join t sh ould be reduced to avoid m isin terpretin g m otion through the m idfoot as dorsiflexion. Th e lateral side of th e an kle sh ould be exam in ed as sign ifican t valgus deform ity can result in impin gem en t of th e fibula on to th e calcan eus. Ten dern ess in th is area m ay be appreciated. Radiographs Diagn ostic studies con sist of weigh t-bearin g AP an d lateral radiograph s of th e foot, as th e deform ity m ay n ot be appreciated on n on –weigh t-bearin g film s (Fig. 19.33). O n th e AP view, the coverage of the talus is evaluated for talon avicular subluxation . This is estim ated by calculatin g the an gle between th e m edial articular edge of th e talus an d th e n avicular. A coverage an gle greater th an 10 degrees is con sidered an abn orm al am oun t of forefoot abduction. On the lateral radiograph , Meary an gle is form ed between th e axis of th e talus an d th e first m etatarsal ray. Norm ally, th ese two axes are parallel; however, they becom e divergent with collapse of th e m idfoot. weigh t-bearin g radiograph s of th e an kle sh ould be evaluated for asym m etry and arthrosis.

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B

A Figure 19.31 (A) Posterior photograph demonstrating the flatfoot deformity associated with

posterior tibial tendon dysfunction. (B) When the patient attempts to perform a single heel rise the heel does not leave the ground. (Reproduced with permission from Kitaoka HB. The Foot and Ankle. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2002.)

Treatment Th e stage of th e disease dictates th e treatm en t. Stage I disease with m in im al deform ity is treated with NSAIDs, orthotics, and physical therapy. In fulm inate ten osynovitis,

Figure 19.32 The “too many toes” sign due to advanced forefoot abduction. (Reproduced with permission from Kitaoka HB. The Foot and Ankle. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2002.)

cast im m obilization or a m odified an kle–foot orthosis is used to decrease ten don strain . An orth osis such as th e UCBL sem i-rigid orth osis supports th e m edial arch wh ile m aintaining the hindfoot in neutral position. If refractory to nonoperative m easures, a tenosynovectomy m ay relieve pain an d h alt th e form ation of ten din osis. Th e treatm en t of stage II disease is con troversial. Historically, it has been treated sim ilarly to stage I, with n on operative m an agem en t an d triple arth rodesis if that failed. Curren tly, stage II disease is treated with a com bin ation of soft tissue recon struction an d various osteotom ies to m ain tain m otion . FDL an d FHL tran sfers for augm entation of the posterior tibial tendon are options for surgical reconstruction . Lengthening of the Achilles ten don or gastrocn em ius is often n ecessary. Bony procedures in clude calcan eal m edial displacem en t osteotom y, lateral colum n lengthening, and m edial cuneiform osteotomy. For severe stage II an d stage III deform ities, arth rodesis is th e m ain stay of treatm en t. Isolated arth rodesis th at in clude th e subtalar join t, talon avicular join t, or calcan eocuboid join t h ave been proposed. In severe rigid deform ities, an d th ose associated with forefoot varus, a triple arth rodesis is recom m en ded.

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A

Figure 19.33 weight-bearing radiographs taken

B

Plantar Fasciitis Heel pain is one of the m ost com m on and potentially disablin g con dition s to affect th e foot. Th ere are a m ultitude of poten tial causes for h eel pain , in cludin g tum ors, in fection, stress fractures, inflam m atory arthropathies, and compressive or m etabolic neuropathies. The m ost com m on plan tar h eel pain is associated with a ch ron ic in juryreparative process th at leads to m icrotears, n ecrosis, an d ch on droid m etaplasia at th e origin of th e plan tar fascia on th e m edial calcan eal tuberosity. Th e con dition is m ore of a ch ron ic degen erative on e th an a true in flam m atory process an d is m ore appropriately referred to as plantar fasciosis.

Pathophysiology Th e plan tar fascia origin ates on th e m edial aspect of th e calcan eal tuberosity and inserts on th e base of the proxim al ph alan x of each toe after dividin g in to five ban ds. With

in a patient with posterior tibial tendon dysfunction and flatfoot. On the lateral, there is collapse of the midfoot with loss of parallelism between the talus and the axis of the first metatarsal (Meary angle) and a decrease in calcaneal pitch (A). Anteroposterior radiographs of both feet clearly show the typical deformities in the left foot when compared with the normal right foot (B). The peritalar subluxation is evident by the increase in the talocalcaneal angle, seen as a separation between the lateral margin of the talar head and medial margin of the anterior calcaneus (arrows). Abduction of the forefoot, represented by the second metatarsal axis, is seen. The talar head is uncovered medially. (Reproduced with permission from Kitaoka HB. The Foot and Ankle. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2002.)

dorsiflexion of th e MTP join ts durin g toe-off, sign ifican t ten sile forces act th rough th e plan tar fascia to elevate th e arch and lock th e transverse tarsal joints creating what has been described as the “windlass m echan ism .’’ Repetitive m icrotraum a to the fascia results in necrosis and degeneration at the origin of the plantar fascia.

Presentation Th e on set is in sidious an d is often preceded by overuse in wom en aged 40 to 65 years old. Sym ptom s in clude m orn ing stiffness and pain that resolves durin g the day with walkin g. Classically, pain is m ost severe when arising in the m orning or gettin g up after sitting and takin g the first step. Jum ping and run nin g can exacerbate the pain . Nigh t pain is n ot com m on , an d its presen ce sh ould warn th e physician to rule out m ore serious con dition s. High -h eeled sh oes typically alleviate symptom s, whereas going barefoot an d wearin g flat shoes worsens symptom s.


Examination Physical exam in ation reveals a poin t of ten dern ess at th e plan tar m edial origin of th e plan tar fascia on th e os calcis. Th ere is often a m oderate to severely tigh t Ach illes ten don complex and restricted an kle dorsiflexion. There m ay be som e fullness and warm th in th e area of th e plan tar m edial h eel an d, occasion ally, h eel pad atrophy. Th e cen tral ban d in th e m idfoot is typically n ot ten der, but passive dorsiflexion of th e toes resultin g in ten sion on th e plan tar fascia m ay elicit pain . Radiographs Diagn osis of plan tar fasciitis is based on h istory an d physical exam in ation. While radiographs m ay reveal specific fin din gs, th ey are reserved for patien ts wh o do n ot respon d to treatm en t to rule out oth er causes of h eel pain . Lateral weigh t-bearin g views m ay dem on strate a plan tar spur at th e origin of th e FDB in approxim ately 50% of patien ts, wh ich signifies chronicity of the con dition. It is thought th at the spur is a result of th e disease process an d not a cause of it. A spur does n ot usually develop at th e origin of th e plan tar fascia. A bon e scan is positive in alm ost all cases, but th is fin din g is n ot specific an d is of little value. MRI an d ultrasound can also help to confirm diagn osis when n eeded. Differential Diagnosis Th e differen tial diagn osis for h eel pain is a lon g procedure but can be easily separated in to n eurological, bony, an d soft tissue causes. Neurological causes include tarsal tunn el syn drom e, en trapm en t of th e first bran ch of th e lateral plan tar (Baxter) or m edial calcaneal nerves, peripheral n europathy, or S1 radiculopathy. Atrophy of th e h eel pad, ten din itis of the Achilles, FHL, or posterior tibial tendons, and plantar fibrom atosis can all cause h eel pain . Bon e sources in clude stress fractures, infections, con tusions, tum or, and arth ritis. Treatment In alm ost all cases of h eel pain , m an agem en t is prim arily nonoperative. Treatm ent usually consists of rest, cold therapy, NSAIDs, Ach illes stretching, and orthotic devices; however, there is little evidence to support these m odalities individually. Studies have sh own that an inexpensive, overthe-coun ter heel cushion is as effective as a custom -m ade orth osis wh en com bin ed with a stretch in g regim en . Various stretch in g program s h ave been described an d usually are plantar fascia –specific or focus on th e Achilles tendon . Nigh t splin tin g h elps to keep th e posterior calf m uscles an d plan tar fascia on stretch wh ile sleepin g. For patien ts wh o have failed to show progress with in 2 m on th s, a cortisone injection at the m edial calcaneal tuberosity can be given. Regardless of the regim en chosen, it is important to stress to patien ts th at patien ce an d dedication to stretch in g is required. Relief from pain m ay take 6 m on th s to 1 year. An alternative therapy receiving m ore attention is extracorporeal shock wave therapy for refractory cases of plan tar fasciitis treated with at least th ree oth er n on opera-

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tive m odalities for 6 m on th s. Th e exact m ech an ism is n ot kn own, but it is though t to stim ulate revascularization of the tissue to prom ote appropriate healing. Surgery is relegated to chronic conditions that do not respon d to n on operative m easures an d is n ecessary in less than 10% of cases. Interventions include partial and com plete plan tar fasciotomy perform ed eith er open or en doscopically. Care should be taken, as releasing the plantar fascia does have consequences on the biom echan ics of the foot. The lon gitudinal arch can collapse, and increased stresses are transferred to the ligam ents an d bones of the m idfoot an d m etatarsals. For patien ts with h eel cord con tracture, a partial release of th e Ach illes or gastrocn em ius m ay alleviate th e pain .

Hallux Valgus Hallux valgus is a disorder of the first ray that involves m etatarsus prim us varus, lateral deviation of the great toe, and a m edial prom inence of the first MTP join t. This prom in en ce is th e m ost visible aspect of th e con dition an d is com m only referred to as a bunion (Fig. 19.34). Wh ile gen etics and certain anatom ic factors such as a planovalgus foot deform ity, heel cord contracture, and ligam entous laxity predispose patien ts to developin g th e con dition , it is alm ost exclusively related to sh oe wear.

Pathophysiology and Classification Th e path ophysiology of h allux valgus in volves a deran gem ent of the intrinsic m usculature of th e foot, resulting in

Figure 19.34 A clinical picture of a typical bunion showing the

prominent medial eminence. (Reproduced with permission from Kitaoka HB. The Foot and Ankle. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2002.)

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lateral deviation of th e great toe an d m edial displacem en t of th e first ray. Th e abductor h allucis usually balan ces th e adductor h allucis; h owever, with th e developm en t of h allux valgus, the abductor hallucis displaces plantarward. With the loss of balance, th e adductor h allucis becom es a deform ing force pulling the toe further in to valgus and pronation due to its in sertion on th e plan tar aspect of th e lateral base of th e proxim al ph alan x. As th e deform ity worsen s, the abductor h allucis, adductor hallucis, FHB, FHL, and even th e EHL becom e deform in g forces, leavin g th e th in dorsal capsule as th e on ly m edial restrain t. Ultim ately, th e sesam oids can displace laterally from under the m etatarsal head. Hallux valgus is usually classified as m ild, m oderate, an d severe on th e basis of th e radiograph ic param eters discussed later.

Presentation Sym ptom s associated with h allux valgus deform ity in clude pain , swellin g, an d in flam m ation over th e m edial em inence caused by shoe wear as well as secon dary hypertrophy of th e overlyin g bursa. Patien ts often com plain th at they are unable to fin d com fortable shoes, while being able to am bulate barefoot with out difficulty. By con trast pain in th e h allux MTP join t wh ile am bulatin g barefoot is a sign of first MTP join t arth ritis. Physical Examination Evaluation of the foot should be perform ed while sitting an d weigh t-bearin g, as th is m ay m ake th e deform ity m ore obvious. Th e foot sh ould be assessed for a pes plan ovalgus deform ity, Ach illes ten don con tracture, ligam en tous laxity, an d sign s of a n eurom uscular disorder. Associated lesser toe deform ities, in cludin g subluxation or dislocation of th e lesser MTP join ts (especially th e secon d digit com m on ly referred to as a crossover toe), tran sfer callosities under th e m etatarsal h eads, bun ion ette deform ity, corn s, an d ham m ertoes are noted. The degree of pron ation and the correctibility of the deform ity should be judged. Range of m otion of th e MTP join t sh ould be m easured, keepin g in m in d th at 70 degrees of dorsiflexion is n ecessary for norm al gait. Th e presence of crepitus is a sign of osteoarth ritic ch an ge with in th e join t. Fin ally, th e first m etatarsocun eiform join t sh ould be assessed for hyperm obility by com parin g m otion of th is articulation to th at of the fifth m etatarsal with the cuboid. Radiographic Findings weigh t-bearing AP and lateral radiographs are essen tial for proper diagn osis of th e deform ity an d surgical plan n in g, as not all bunions are treated th e sam e. The degree of h allux valgus and m etatarsus prim us varus deform ity, first MTP join t con gruity, degen erative ch an ges of th e MTP join t, an d eviden ce of sesam oid subluxation determ in e th e optim al treatm en t approach an d are assessed on radiograph s (Fig. 19.35).

Figure 19.35 The angles and degree of sesamoid subluxation

used to assess severity of hallux valgus. (Reproduced with permission from Johnson D, Pedowitz RA. Practical Orthopaedic Sports Medicine and Arthroscopy. Philadelphia, PA: Lippincott Williams & Wilkins, 2007.)

Th e h allux valgus an gle, subten ded by a lin e bisectin g th e first m etatarsal an d th e proxim al ph alan x, is n orm ally less than 15 degrees. The interm etatarsal angle of the first and second m etatarsals is determ ined by bisecting th e longitudinal axis of each , an d an an gle of 9 degrees or less is n orm al. A hallux valgus an gle of less th an 20 degrees with an interm etatarsal an gle less than 11 degrees and sesam oid subluxation of less than 50% are con sidered a m ild deform ity. A h allux valgus angle of 20 to 40 degrees, an interm etatarsal angle less than 16 degrees, and sesam oid subluxation 50% to 75% are considered m oderate. Hallux valgus angles greater than 40 degrees, interm etatarsal angles greater than 16 degrees, an d sesam oid subluxation m ore th an 75% are con sidered severe. Severe h allux valgus is usually associated with first MTP joint incongruity. Th e distal m etatarsal articular an gle describes th e orien tation of th e articular surface in relation to th e lon gitudin al axis of the ray. A line con nectin g the m edial an d lateral articular m argins of the h allux m etatarsal head an d a line


bisectin g th e lon gitudin al axis of th e first m etatarsal form the angle. Th is angle can impact the surgical treatm en t plan.

Differential Diagnosis Hallux valgus interphalan geus is a deform ity of th e in terph alan geal join t of th e great toe. Th e an gle between th e proxim al an d distal ph alan x on an AP radiograph n orm ally m easures 10 degrees. This deform ity can resem ble h allux valgus. Treatment Treatm ent of hallux valgus in the early stage is non operative and includes selection of appropriate sh oes with a high , wide toe box. If an associated plan ovalgus deform ity exists, orth otic devices m ay be h elpful. Surgical in terven tion is in dicated wh en con servative m easures fail, an d th ere is progression of th e deform ity, in creasin g difficulty with sh oe wear, an d in volvem en t of th e secon d MTP join t m an ifested as a crossover deform ity. Contraindication s in clude spasticity, ligam en tous laxity from Marfan or Ehlers–Dan los syn drom e, an d vascular or skin in sufficien cy. Th e prin ciple of surgical treatm en t is to correct all deform ities while m ain taining a functional foot. A num ber of surgical option s exist, ran gin g from soft tissue procedures to m ultiple osteotom ies an d fusion s. Th ere is n o clear-cut con sensus on optim al treatm ent (Fig. 19.36). Decisions are

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based on th e age an d activity level of th e patien t, th e presen ce of arth rosis, hyperm obility of th e first ray, con gruen cy of th e MTP join t, physical sh ape of th e m etatarsal h ead, an d th e h allux valgus an d in term etatarsal an gles. A distal m etatarsal osteotomy is th e preferred treatm ent for a m ild hallux valgus deform ity, with the Mitchell and ch evron osteotom ies being m ost com m on. In m ost bun ion ectom ies, a distal soft tissue procedure to realign th e MTP join t is perform ed. The m odified McBride procedure achieves this by correcting all soft tissue components of the MTP joint deform ity. A m oderate hallux valgus is treated in a sim ilar fash ion but m ay require a proxim al osteotomy, rath er th an a distal osteotom y. For severe h allux valgus, a proxim al m etatarsal osteotomy is com m on ly perform ed in con jun ction with a distal soft tissue procedure. Proxim al m etatarsal osteotom y provides powerful correction of m etatarsus prim us varus greater th an 15 degrees. Tech n iques in clude crescen tic, open in g an d closin g wedge osteotom ies, as well as a proxim al chevron osteotomy. When hyperm obility of th e first ray is presen t, a m etatarsocun eiform fusion m ay be required with a distal soft tissue procedure. Arthrosis of the first MTP joint associated with h allux valgus can be aggravated by surgery. In th is situation , a resection arthroplasty or arthrodesis of the first MTP joint is indicated. A resection arthroplasty, or Keller procedure, involves excising a segm ent of the proxim al phalanx an d th e m edial em in en ce. Th is decom presses th e MTP join t, resultin g in relaxation of th e con tracted lateral structures. Alth ough it was a popular procedure in th e past, curren t prim ary in dication s for its use in clude im pen din g m edial skin breakdown and patients who walk only m inim ally. Occasionally, it is used as a salvage procedure in failed bun ion surgery. Arth rodesis of th e first MTP join t h as been a reliable and durable procedure that is indicated for m anagem ent of severe deform ities associated with degen erative join t disease, n eurom uscular con dition s, an d salvage procedures. Th e toe sh ould be fused in 10 to 15 degrees of dorsiflexion an d 15 to 20 degrees of valgus.

Hallux Rigidus Hallux rigidus is a pain ful loss of m otion of the first MTP join t due to arth rosis. Degen erative ch an ges result in a dorsal m etatarsal osteophyte an d loss of dorsiflexion . Alth ough it m ay occur bilaterally, often on e side is usually m ore advanced. It generally occurs in m iddle-aged and older person s but m ay also occur in active youn g people.

Figure 19.36 An algorithm for the treatment of hallux val-

gus (HV). IM, intermetatarsal; MC, metatarsal cuneiform; MTPJ, metatarsophalangeal joint; STP, soft tissue procedure. (Reproduced with permission from Johnson D, Pedowitz RA. Practical Orthopaedic Sports Medicine and Arthroscopy. Philadelphia, PA: Lippincott Williams & Wilkins, 2007.)

Pathophysiology and Classification Hallux rigidus is a m anifestation of arthrosis of the first MTP join t and is caused by traum a, OCD of the m etatarsal h ead, con gen ital deform ity, an d system ic arth ritides. Mechanical blocks from osteophytes on the dorsal aspect of th e proxim al ph alan x an d th e m etatarsal h ead reduce th e available range of motion, especially dorsiflexion (Fig. 19.37).

796


Figure 19.37 Dorsal osteophytes result in

loss of range of motion and pain with dorsiflexion. (Reproduced with permission from Kitaoka HB. The Foot and Ankle. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2002.)

Presentation Patien ts com m only complain of pain, swelling, and loss of m otion in th e great toe. Symptom s are worse in th e m orn in g an d are aggravated by prolon ged walkin g or stan din g. Sh oes with elevated h eel lifts exacerbate pain by furth er lim itin g th e am oun t of dorsiflexion .

Examination Th e first MTP join t ten ds to be en larged, warm , an d swollen with decreased dorsiflexion . If th e pain is severe, patien ts m ay limp in to th e office. Adorsal prom in en ce is m ost often palpable at th e dorsom edial m etatarsal h ead, an d sign ifican t join t line tenderness m ay be present. With tim e an d severity, a m ediolateral exostosis m ay develop. Radiographs Radiograph s sh ow a decrease in th e join t space, sclerotic join t m argin s, flatten in g of th e first m etatarsal h ead, an d subch ondral cyst form ation consistent with progressive arth rosis.

Treatment In itial treatm en t is n on operative m an agem en t with NSAIDs an d sh oe an d activity m odification . NSAIDS h elp to reduce th e in flam m ation an d pain related to syn ovitis about th e first MTP joint. High-impact activities can be substituted with low-impact activities such as swim m ing and bikin g. Modification s to sh oe wear in clude a stiff sole with a steel sh an k or carbon fiber footplate, or a rocker-bottom attachm ent to m inim ize stress and m otion across the MTP join t durin g th e toe-off ph ase of gait. In traarticular steroid injections should be used sparingly. Wh en n on operative m an agem en t fails, surgical options include ch eilectomy, interpositional arthroplasty, joint replacem en t, MTP join t fusion , an d resection al arth roplasty. A cheilectomy is indicated for patien ts with m ild to m oderate disease, wh ose sym ptom s are related to th e dorsal impingem ent during toe-off. Approxim ately 20% to 30% of th e dorsal aspect of th e m etatarsal h ead is rem oved alon g with th e dorsal exostosis an d osteophytes on th e proxim al ph alan x to ach ieve 60 degrees to 80 degrees of dorsiflexion (Fig. 19.38). If arthrosis of th e joint is severe an d m ore diffuse, a first MTP fusion is a reliable operation to relieve

Figure 19.38 A cheilectomy removes approximately

20% to 30% of the dorsal metatarsal head and the dorsal osteophyte to regain motion at the first metatarsophalangeal joint. (Reproduced with permission from Kitaoka HB. The Foot and Ankle. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2002.)


pain . Th is provides a stable join t for patien ts wh o wish to rem ain active. Som e auth ors h ave advocated resurfacing the join t with eith er biologic m aterials or implants. For lower-dem and patients with severe arthrosis of th e joint, a Keller resectional arthroplasty can also provide pain relief. Th is sh ould n ot be perform ed if th ere is sign ifican t tran sfer m etatarsalgia. A downside to th e procedure is a loss of push -off stren gth at th e MTP join t.

Morton Neuroma Morton neurom a is a compression neuropathy of the plantar in terdigital n erves th at is a com m on cause of forefoot pain .

Pathophysiology and Classification Th e plan tar digital n erves, wh ich are th e term in al bran ch es of th e m edial an d lateral plan tar n erves, are compressed by the distal edge of the transverse interm etatarsal ligam ent at the level of th e m etatarsal heads as they pass inferiorly (Fig. 19.39). Th e repetitive traum a with toe flexion an d exten sion results in perin eural fibrosis, dem yelin ization, degeneration of th e n erve, an d en don eural edem a. Because th ere is n o axonal proliferation and overgrowth, this condition

797

is n ot truly a neurom a but rather an interdigital neuritis. Tigh t an d h igh -h eeled sh oes are th ough t to con tribute to th e developm en t. Activities th at result in excessive exten sion of toes, such as running, liftin g, and ballet dancing m ay increase th e risk of Morton neurom a. Th e secon d an d th ird in terdigital n erves are m ost com m only affected—with approxim ately 85% of cases in volving the third web space and 15% involving the second. The th ird in terdigital n erve is at h igh er risk because of its un ique anatomy receiving contributions from both the lateral and m edial plantar n erves. Neurom as of the first and fourth web spaces are rare.

Presentation Patien ts presen t with vague, in term itten t, burn in g pain in th e area of th e m etatarsal h eads th at in creases in in ten sity and duration durin g weigh t-bearing. Th e adjacent toes m ay h ave n um bn ess. Wearin g wide sh oes an d rubbin g the feet typically helps. Physical Examination Deep palpation between th e m etatarsal h eads or passive exten sion of th e toes m ay reproduce th e pain . Sen sation m ay be dim in ish ed in th e th ird an d fourth toes. Compression of th e m etatarsal h eads m ay result in a palpable Mulder click as the n eurom a pops out between th e m etatarsal heads. Diagn osis is con firm ed by in jectin g a local an esth etic in to th e webspace with relief of sym ptom s. Special Tests CT, MRI, and ultrasoun d have all been used to diagn ose Morton neurom a; however, these are seldom necessary an d sh ould not be obtain ed routinely. Differential Diagnosis Other causes of forefoot pain include m etatarsalgia, osteon ecrosis of th e m etatarsal h ead, stress fractures, in flam m atory arthropathy, and ganglion cysts.

Figure 19.39 In Morton neuroma, the digital nerves are com-

pressed by the intermetatarsal ligament. (Reproduced with permission from Kitaoka HB. The Foot and Ankle. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2002.)

Treatment Treatm ent consists of m odifying shoes and placing m etatarsal pads proxim al to the third and fourth m etatarsal h eads to h elp spread th e tran sverse m etatarsal ligam en t and un load th e impingem ent on th e nerve. External shoe m odifications, in cluding a m etatarsal bar, m ay also h elp to un load th e forefoot. Physical th erapy, cryoth erapy, an d ultrasound are alternatives. Steroid and/ or alcohol injections h ave also been advocated. Operative intervention is reserved for refractory cases. Options include neurectomy with or without n erve burial into m uscle, transverse interm etatarsal ligam ent release, and en doscopic decompression. Morton neurom a is m ost com m on ly approach ed dorsally but can exposed via a plan tar in cision . Surgical in terven tion h as excellen t results in up to 85% of cases. Complications in clude symptom atic endstum p n eurom a an d recurrence. With recurrence, a plantar

798


approach sh ould be used because it is exten sile, allowin g a m ore proxim al excision of th e n erve.

RECOMMEND READINGS Herscovici D Jr, An glen JO, Arch deacon M, Can n ada L, Scaduto JM. Avoidin g com plication s in th e treatm en t of pron ation -extern al

rotation ankle fractures, syndesm otic injuries, and talar neck fractures. J Bone Joint Surg Am. 2008;90:898 –908. Mann RA. Disorders of the first m etatarsophalangeal joint. J Am Acad Orthop Surg. 1995;3:34 –43. Rech t MP, Don ley BG. Magn etic reson an ce im agin g of th e foot an d ankle. J Am Acad Orthop Surg. 2001;9:187 –199. Robin son HN, Pasapula C, Brodsky JW. Surgical aspects of th e diabetic foot. J Bone Joint Surg Br. 2009;91:1 –7.

Index Note: Page n um bers followed by f an d t in dicates figure an d table respectively.

A

Abduction orth osis, 327, 327f Abductor digiti m in im i (ADM), 590, 758, 759 Abductor pollicis brevis (APB), 589 Abductor pollicis lon gus (APL), 588 Abrasive wear, 27 Abscesses differen tial diagn osis of, 649 path ophysiology of, 649 presen tation / physical exam in ation of, 649 radiograph ic fin din gs/ special studies of, 649 treatm en t of, 649 Accessory deep peron eal n erve, 66 Acclim atization , 186 –187 Acetabular fracture assessm ent of CT study, 223 physical exam in ation , 220 plain -radiograph ic assessm en t, 220, 221f, 223 classification of, 222f, 223 non operative treatm ent, 223 –224 posterior wall fractures, 224 –225, 225f, 226f surgical exposures for acetabular fixation , 224t surgical m an agem en t, 224 Acetam in oph en , 139, 189 Ach illes ten don , 701, 757 path ology differen tial diagn osis of, 788 exam in ation of, 787 –788 im agin g studies in , 788 path ophysiology an d classification of, 787 presen tation of, 787 reiter syn drom e, 788 treatm en t of, 788 ruptures ch ron ic ruptures in , 770 Matles test in , 769 path ophysiology an d classification , 769, 769f physical exam in ation of, 769 presen tation of, 769 radiograph ic fin din gs of, 770 special tests for, 770 Th ompson test in, 769, 769f treatm en t of, 770

Ach on droplasia, 270 differen tial diagn osis, 272 history and physical exam in ation, 270 –271 acrom elic shortening, 270 –271 m esom elic shortening, 270 rh izom elic sh orten in g, 270 path ophysiology, 270 presen tation , 271, 271f radiograph s, 271, 272f tests for, 271 –272 treatm en t, 272, 273f, 274 Acid-fast bacillus (AFB), 558 Acquired adult flatfoot deform ity exam ination of, 790 flatfoot deform ity, 791f Jack test in , 790 path ophysiology an d classification of, 790 presen tation of, 790 radiograph s of, 790 treatm en t of, 791 Acrom iale, defin ition of, 537 Acrom ioclavicular (AC) join t, 501, 502f, 504 arthritis of differen tial diagn osis, 542 osteophyte form ation , 542, 542f path ophysiology, 541 physical exam in ation , 541 –542 presen tation , 541 radiograph ic fin din gs, 542 special tests, 542 treatm en t of, 542 sprains, in sh oulder, 525 classification of, 526 –527 differen tial diagn osis, 527 m echanism of injury, 527, 527f patien ts presen tation , 527 physical exam in ation , 527 radiograph ic exam in ation , 527 special tests, 527 treatm en t of, 527 –528 stabilization of, 506f Acrom ion , role of, 502 Active biceps compression test, 534 Acute gout attacks, treatm en t of, 640 Acute m oun tain sickn ess, 187 Acute respiratory distress syn drom e (ARDS), 205 Adam s forward ben din g test, 360, 361f Adductor pollicis (AP) m uscle, 590

Adh esive capsulitis, 501 in shoulder differen tial diagn osis, 547 path ophysiology an d classification , 546 physical exam in ation , 546 –547 presen tation , 546 radiograph ic fin din gs, 547 special tests, 547 Adh esive wear, 27 Adolescen t idiopath ic scoliosis (AIS), 359. See also Idiopathic scoliosis Len ke classification for, 360f Adult scoliosis, 484 –486, 486f defin ition of, 484 evaluation of patien t, 485 patien t presen tation of, 485 surgery for, 486 treatm en t of, 485 –486 Advan ced Traum a an d Life Support System (ATLS), 193, 436, 674 Aggrecan , 12, 13f Aging, effect on articular cartilage, 14 Allis reduction tech n ique, for posterior h ip dislocation s, 668, 668f Allograft h am strin g ten don , usage of, 528 Altitude illn ess, 187 Am erican Academy of Pediatrics, 167 Am erican Heart Association , 167, 184 Am erican Rh eum atism Association , 126, 127t Am erican Spin al In jury Association (ASIA), 436 Am in ogylcosides, 80, 81t Am itriptylin e (Elavil), 130 Amyoplasia. See Arth rogryposis An abolic steroids, 190 An alysis of varian ce (ANOVA) test, 30, 36 An drosten edion e, 190 An eurysm al bon e cyst (ABC), 151, 152f, 488 An kle –brach ial in dices (ABIs), 719 An kle foot orth osis (AFO), 770 An kle fractures classification of, 763 –766 differen tial diagnosis of, 766 im aging of, 766 Lauge–Hansen classification system of, 763, 764f–765f m aison neuve fracture, 766 m echanism of in jury, 766 pediatric, 431

800

Index

An kle fractures (Contd.) Salter–Harris classification system , 431 Tillaux fractures, 431, 432f tran sition al fractures, 431 treatm en t for, 431, 432f triplan e fractures, 432, 433f physical exam in ation of, 766 presen tation of, 766 radiograph ic m arkers for, 767f supin ation in juries in, 766 treatm en t of, 766 –767 Weber classification system of, 763, 763f An kle join t, an atomy of, 754 –756 An kle sprain s an d syn desm osis in juries, 767 brostrum procedure in , 768 classification of, 768 differen tial diagn osis of, 768 fibular squeeze test, 768 im aging of, 768 m echanism of in jury, 768 physical exam in ation of, 768 presen tation of, 768 treatm en t of, 768 –769 An kylosin g spon dylitis, 130 –132, 131t An n ular pulleys, 587 An terior atlan toden ts in terval (aADI), 469 An terior ban d of th e in ferior glen oh um eral ligam en t (AIGHL), 529 An terior cervical discectomy an d fusion (ACDF), 466 An terior cord syn drom e, 200 –201, 202f, 436. See also Spin al cord in jury (SCI) An terior cruciate ligam en t (ACL), 25, 699 anterior drawer test for, 706 of kn ee, 706 Lach m an test for, 706, 707f pivot sh ift test for, 706 sprain s, 737 classification of, 721 complication s of, 723 differen tial diagn osis of, 722 Lach m an test in , 722 m echanism of in jury, 721 –722 occurren ce of, 721 patien ts presen tation of, 722 physical exam in ation of, 722 radiograph ic exam in ation of, 722 relevant anatomy of, 722 Segun d sign in , 722, 722f special tests for, 722 treatm en t of, 722 –723 two bun dles of, 699f An terior in ferior glen oh um eral ligam en t (AIGHL), 503 An terior in ferior iliac spin e (AIIS), 653 An terior in ferior tibiofibular (AITFL), 756f An terior in terosseous n erve (AIN), 410, 629 An terior in terosseous syn drom e differen tial diagn osis of, 629 path ophysiology of, 629 physical exam in ation of, 629 presen tation of, 629

special studies in , 629 treatm en t of, 629 An terior superior iliac spin e (ASIS), 653, 701 An terior talofibular ligam en t (ATFL), 755, 756f an terior draw test of, 761f An terolateral bowin g an d CPT of tibia, 337 classification system s, 337 –338 Crawford classification, 338f differen tial diagn osis, 338 im agin g, 338 path ophysiology, 337, 337f presen tation an d physical exam in ation , 338, 338f treatm en t, 338 –339, 339f An terom edial facet, role of, 568 An tibiotic th erapy adult osteomyelitis, 83 –85 m usculoskeletal infections, 80 –81, 81t necrotizin g fasciitis, 95 pediatric osteomyelitis, 89 septic arth ritis in ch ildren, 90 An tigen -presen tin g cells (APCs), 118 Antim etabolites, 80, 81t An tin uclear an tibodies (ANAs), 119 Arcuate artery, 759 Arth ritis of AC join t, 541 –542 of GH join t, 542 –546 Arth ritis m utilan s, 639 Arth ritis patien t, evaluation of diagn ostic testin g, 124 –125 history, 122 m onoarticular arthritis, 122, 122t physical exam in ation , 124 polyarticular arth ritis, 122, 123t synovial fluid an alysis, 125 Arth rography con ven tion al, 45 –46 in frozen shoulder, 547 in shoulder, 520 Arth rogryposis, 258 classification , 259 differen tial diagn osis, 259 –260 distal arth rogryposis, 259, 259f history and physical exam in ation , 259 incidence of, 258 path ophysiology, 258 –259 presen tation , 259, 259f treatm en t, 260 –261, 260f Arth roscopy, of kn ee, 742 Articular cartilage, 11, 214 com position of, 13t histologic zon es, 11, 12f calcified zon e, 11 lam ina splendens, 11 radial zone, 11 tangen tial zon e, 11 tidem ark, 11 tran sition al zon e, 11 m echanical properties of, 24 –25 m orphology and physiology aggrecan, 12 –13 biom ech an ical role, 14, 14f

cartilage m atrix, 12 cartilage n utrition , 13 ch on drocytes, 11 collagen , 12 extracellular m atrix, 13 m etabolism , 13 path ologic ch an ges aging, 14 osteoarth ritis, 14, 15f traum a to articular surface, 14 Articular fractures, 214, 215f Asth m a, 184 –185 Atasoy–Klein ert V-Y advan cem en t flap, 613f. See also Skin an d n ail traum a Atlan ta Scottish Rite brace, 327 Atlan toaxial in juries, 394f, 395 Atlan toaxial rotatory displacem en t, 382, 383f Atlan toaxial rotatory subluxation , radiographic findings, 383f Atlan toden s in terval (ADI), 441 Atlas fractures, 393, 394f, 395 Atraum atic m ultidirection al bilateral reh abilitation in ferior capsular sh ift (AMBRI), 528 Atypical lipom as, 160 Autoan tibodies, 119 Autologous ch on drocyte implan tation (ACI), 718 Avascular n ecrosis (AVN), 502, 666, 668 Aviator astragalus, 770 Axillary radiograph , usage of, 545 Axon otm esis, 71 –72, 72f

B

Baby Ben n ett, 600 Back pain , in ch ildren , 387 –388 differen tial diagn osis an d treatm en t, 388 –391 physical exam in ation , 388 presen tation , 388 special tests for, 388 Baclofen , 244 Baker cyst, 702 differen tial diagn osis of, 730 patien ts presen tation of, 730 physical exam in ation of, 730 radiograph ic exam in ation of, 730 relevant anatomy of, 730 special tests for, 730 treatm en t of, 730 –731 Ballottem en t test, kn ee, 705. See also Kn ee an d leg in juries Ban kart lesion , of h um eral h ead, 529, 529f Barlow test, 301, 302f Baum an n an gle, 408, 409f B cell, 119 Becker m uscular dystrophy, 257 Belly press test, usage of, 517 Ben din g, 23 Ben n ett fracture, 600, 600f Bern ese periacetabular osteotomy, 310, 310f Bicipital apon eurosis, 552 Bicipital groove, usage of, 502

Index Biom aterials and implan ts im plan t failure, 26 –27 corrosion , 27 fatigue, 27 wear, 27, 27f m etals, 25 –26 polym ers, 26 study of, importan ce of, 20, 25 Biom ech an ics elasticity, 21 force, 20 –21 loadin g, 23 m echan ical properties of tissues articular cartilage, 24 –25 bon e, 24 collagen ous tissues, 25 stress an d strain , 21 –22 stress con cen tration effects, 23 stress–strain curve, 22 –23, 22f study of, importan ce of, 20 viscoelasticity, 24 Biostatistics, definition of, 29 Bipartite patella, in anterior knee pain, 728 Birth day syn drom e, 244 Bisph osph on ates in osteoporosis treatm en t, 106 –107, 107t adverse effects of, 106, 107f for Paget’s disease, 114 Bite woun ds path ophysiology of, 650 presen tation / physical exam in ation of, 650 radiograph ic fin din gs/ special studies of, 650 treatm en t of, 650 β -lactam an tibiotics, 80, 81t Blockin g, 70 Bloun t disease (tibia vara), 334 differen tial diagn osis, 335 –336 Lan gen skiö old classification , 334, 334f path ophysiology, 334 presen tation an d physical exam in ation , 334, 334f, 335f radiograph ic evaluation , 335, 335f treatm en t, 336, 336f Bon e, 15 cells, 16 –17 osteoblast, 16, 18f osteoclast, 17, 18f osteocytes, 16 –17 circulation , 16, 17f composition of, 18t fun ction s, 207 m aterial properties of, 101 m atrix and form ation, 17 –18, 18f bon e collagen , 18, 19f h ole zon es, 18 m echan ical properties of, 24 m ineral phase of, 19 calcium in , 54 m orph ology and physiology, 15 –16 can aliculi, 15 can cellous (trabecular) bon e, 15, 16f, 24 cortical (compact) bon e, 15, 24 Haversian system , 15

in terstitial lam ellae, 16 lam ellar bone, 15 norm al bon e, 15 osteon al system s, 16 outer circum feren tial lam ellae, 16 woven bon e, 15 rem odelling, 20, 99 resorption, 19 –20, 100 structural properties of, 101 –102 Bon e densitom etry, 58 Bon e m in eral den sity (BMD), 99 Bon e tum ors anatom ic location of, 148t biopsy of, 147 guidelines for, 147t classification of, 148t differen tial diagn osis, 148, 148t im aging m odalities, 146 bon e scan s, 147 CT, 146 MRI, 146 –147 PET im agin g, 147 radiograph ic fin din gs, 146t patien t evaluation , 145 –146 radiograph ic differen tial diagn oses of, 148t stagin g studies, 147 En n ekin g Surgical Stagin g System , 147t Bon e turnover, 99 assessm en t of, 99 bioch em ical m arkers of, 99 –100, 100t osteoclast-m ediated bon e resorption , 100 –101, 101f Bony m allet fin ger, 597 Borrelia burgdorferi, lym e disease by, 291 Both bone forearm fractures, 608, 609f. See also Uln ar an d radial sh aft fractures Botulinum toxin, 244 Bouchard n odes, 633 Boutonierre deform ity, Elson test for detection of, 623f Brachialgia, 473 Brachial plexus palsy, 347 –348, 348f Brittle bon e disease. See Osteogenesis imperfecta (OI) Brown -Sequard syndrom e, 200, 201f, 436. See also Spin al cord in jury (SCI) Bulbocavernosus reflex, in SCI, 435 –436 Bun ion , 793. See also Hallux valgus Burning pain , 513. See also Sh oulder Burst fractures, 449, 450f, 454 –456, 455f. See also Thoracolum bar traum a treatm en t of, 449, 456

C

Caffeine, 189 –190 Calcaneal lengthening osteotomy, 248, 248f Calcaneofibular ligam en t (CFL), 754, 756f Calcaneovalgus foot deform ity, 340 –341, 341f Calcaneus fractures Bö h ler, tuber an gle of, 776f classification of, 774 con stan t fragm en t, 774

801

differential diagnosis of, 776 extraarticular fractures, 774 Gissane, crucial angle of, 776f im agin g of, 774 intraarticular fractures, 774 intraoperative im agin g of, 777 m echanism of injury, 774 physical exam in ation of, 774 presen tation of, 774 San ders classification of, 774, 775f treatm ent of, 776 –777 Calcific ten donitis, in sh oulder differen tial diagn osis, 541 path ophysiology an d classification of, 540 physical exam in ation , 541 presen tation of, 540 radiographic findings, 541, 541f special tests, 541 treatm en t of, 541 Calcitonin, 99 for Paget’s disease, 114 in treatm ent of osteoporosis, 106 Calcium hydroxyapatite, 17, 19 Calcium pyrophosphate deposition disease (CPPD), 135, 639 Camper ch iasm a, 586 Cancellous bone, 15, 24, 207 Cancellous bone grafting, role of, 603 Candida albicans, 647 Cantu an d Am erican Academy of Neurology gradin g system , for con cussion , 173t Capitate fractures. See also Hand an d wrist classification of, 605 m echanism of injury, 605 presen tation an d physical exam in ation , 605 radiographic findings, 605 treatm en t of, 605 C-arm , 59 C-arm fluoroscopy, 46 Carpal and ulnar tun nels, 627f Carpal instability. See also Han d an d wrist classification of, 610 –611 Mayfield stages of, 610, 611f m echanism of injury, 611 physical exam in ation , 611 presentation, 611 radiographic findings, 611 –612 Terry-Thom as sign for, 610, 610f treatm en t of, 612 Carpal instability com bined (CIC), 610 Carpal instability dissociative (CID), 610 Carpal instability nondissociative (CIND), 610 Carpal tunn el compression test, in CTS, 626 Carpal tunn el syndrom e (CTS), 607 carpal tun n el compression test in , 626 corticosteroid in jection s in , 626 path ophysiology of, 626 ph alen test in , 626 physical exam in ation of, 626 presen tation / m ech an ism of in jury, 626 special studies in , 626 tests for, 628t

802

Index

Carpal tunnel syndrom e (CTS) (Contd.) tin el test in , 626 treatm en t of, 626 Carpom etacarpal (CMC) joint, 588 Carpus, 583 –584, 585f. See also Han d and wrist Cartilage, 11 types of, 11 composition of, 12t elastic cartilage, 11 fibrocartilage, 11 hyalin e cartilage, 11 Case-control study, 33 –34 Case series, 33, 34 Cathepsins, 14 Cauda equina syndrom e, 436, 480. See also Spin al cord in jury (SCI) sign s an d symptom s of, 480 Cauliflower ear, 175, 175f, 274 Causalgia, 641. See also Complex regional pain syn drom e (CRPS) Ceftriaxone, 650 Cen tral cord syndrom e, 200, 201f, 436. See also Spin al cord in jury (SCI) Cephalom edullary device, in intertrochanteric hip fractures, 679, 680f Cerebral contusion, 173 Cerebral palsy (CP) classification , 241, 242f history an d physical exam ination, 241 –242, 243f ankle dorsiflexion, m easurem en t of, 242, 243f h am strin g tigh tn ess, assessm ent of, 242, 243f h ip flexion con tracture, assessm ent of, 242, 243f m anagem ent, 244 path ophysiology, 241 presen tation , 241 radiograph s, 242 –243, 244f special studies for, 243 treatm en t of region al deform ities ankle, 246 –248, 246f, 247f h ip, 244 –245, 244f, 245f kn ee, 245, 245f, 246f upper extrem ity, 248 –249, 248f Cervical degenerative disk disease, 467 Cervical myelopathy, 463 –465, 464f Cervical radiculopathy, 462t CT scan of, 462 diagn ostic studies of, 462 electromyography, 462 –463 history of, 461 MRI of, 462 natural h istory, 463 physical exam in ation of, 461 –462 plain radiograph s of, 462 Spurlin g’s sign , 461 Cervical spine, 460 –461 anatomy, 439 –441 CT scan of, 441 lateral cervical spine radiographic lines, 441f radiographs of, 441 –443 wacken h eim ’s lin e, 441

arm pain predom inance, 473 cervical myelopathy, 463 –465, 464f cervical radiculopathy, 461 –463 cervical spin e algorith m , 470, 471f cervical spin e clin ical con dition s, 465 –467 cervical spon dylosis, 467 –468, 468f con servative treatm en t, 470 –472 history an d physical exam in ation , 461 neck pain predom in an ce, 472 –473 rheum atoid arthritis, 468 –470, 469f Cervical spine algorithm , 470, 471f Cervical spine injury severity score (CSISS), 438 Cervical spondylosis, 467 –468, 468f treatm en t of, 467 Chance fractures, 397, 398f Chance injuries, 456 –458. See also Thoracolum bar traum a radiographic characteristics of, 457f Charcot arthropathy, 785. See also Diabetic foot differen tial diagn osis of, 786 –787 MRI in, 786 path ophysiology an d classification of, 786 physical exam in ation of, 786 presen tation of, 786 radiographic fin din gs of, 786 special tests for, 786 treatm en t of, 787 Charcot –Marie –Tooth (CMT) disease, 253 differen tial diagn osis, 255 –256 gen etic testin g, 255 path ophysiology an d classification , 253 physical exam in ation , 254 –255, 255f presen tation , 254, 254f radiographs, 255, 255f treatm en t, 256, 256f Charcot restraint orthotic walker (CROW), 787 Cheiralgia paresth etica. See Wartenberg syndrom e Cherub dwarf, 274 Chiari osteotomy, 311, 311f Children, general and regional problem s in, 235 ach ondroplasia, 270 –274 anterolateral bowing and CPT of tibia, 337 –339 arth ritis juvenile rh eum atoid disease, 292 –296 Lym e disease, 291 –292 tran sien t syn ovitis, 291 arth rogryposis, 258 –261 Blount disease (tibia vara), 334 –336 Charcot –Marie –Tooth disease, 253 –256 ch rom osom al an d in h erited syn drom es Down syn drom e, 280 –282 Marfan syndrom e, 282 –284 diastroph ic dysplasia, 274 –275 foot an d an kle calcan eovalgus foot, 340 –341 clubfoot, 344 –346 con gen ital deform ities of toes, 346 con gen ital vertical talus, 341 –342 flexible flatfoot, 342 –343

juven ile h allux valgus, 346 m etatarsus adductus, 340 osteoch on droses, 346 tarsal coalition , 343 –344 h an d an d wrist con gen ital trigger th um b, 350 –351 Madelung deform ity, 349, 350f polydactyly, 349 –350, 351f syn dactyly, 349, 350f h ip, 297 con gen ital coxa vara, 329 –330 developm en tal dysplasia of th e h ip, 299 –312 em bryon ic h ip, 297f Legg–Calve–Perth es disease, 321 –328 n orm al developm en t, 297, 297f, 298f slipped capital fem oral epiphysis, 312 –321 un treated dislocation of, 298f vascular an atomy, 298, 299f idiopathic toe-walking, 339 –340 kn ee an d leg discoid m en iscus, 332 –334 Osgood –Sch latter disease, 331 osteoch on dritis dissecan s, 331 –332 popliteal cysts, 332 lim b deficiencies fibular h em im elia, 288 –289 proxim al fem oral focal deficien cy, 284 –288 radial clubhan d, 289 –291 tibial h em im elia, 289 lim b length discrepancy, 351 –356 limping child, 356 –358 m etabolic and endocrine disorders rickets, 261 –265 m ucopolysacch aridoses, 276 –280 m ultiple epiphyseal dysplasia, 275 –276 m uscular dystrophy, 256 –258 n eurom uscular disease, 240 –241 cerebral palsy, 241 –249 myelodysplasia (spin a bifida), 249 –253 osteogen esis imperfecta, 265 –268 osteopetrosis, 268, 269f scurvy, 268, 270 sh ort stature an d skeletal dysplasias, 270 sh oulder an d elbow brach ial plexus palsy, 347 –348 con gen ital dislocation of radial h ead, 348, 349f con gen ital pseudarth rosis of clavicle, 347 con gen ital radiouln ar syn ostosis, 349, 349f Spren gel deform ity, 346 –347 spondyloepiphyseal dysplasia, 276 torsional and angular variations, 235 –240 Children , orthopaedic in juries in , 398. See also Pediatric m usculoskeletal traum a an d adults in juries, differen ce between , 399t Child skeleton, characteristics of, 399 –401 Chi-square test, 36 Ch on droblastom a, 151, 151f

Index Chondrocytes, 11 Chondroectoderm al dysplasia, 272 Chondrom alacia, 727. See also Patellofem oral pain syn drom e Chondrosarcom as, 156, 158f Chopart joint. See Tran sverse tarsal join t Chordom a, 158, 161f, 490 –491. See also Spin e MRI in, 490, 490f Cierny–Mader staging system , for adult osteomyelitis, 83t Cinacalcet hydrochloride, 112 Circum ferential binder, 217 Clavicle fractures and dislocations, 404, 405f Clavicle fractures, in shoulder classification of, 520, 521f differen tial diagn osis, 522 m echan ism of injury, 520 patien ts presen tation , 520 physical fin din gs, 520 –521 radiograph ic evaluation , 521, 522f special tests, 522 treatm en t of, 522 –523, 523f Clavicle, role of, 502f Clin damycin , 80, 81t Closed reduction and percutaneous pin n in g (CRPP), 410, 411, 413 Clubfoot (talipes equinovarus), 344 –346, 345f Cobb angle, m easurem en t of, 362, 363f Cohen’s kappa, 36 Cold illn ess, 187 Colem an block test, 255, 255f Collagen, 12 Collagenase, 13 –14, 19 Com m inuted fractures, 213 Com m otio cordis, 179 Compartm en t syn drom e, 181 –182, 202 –205, 203f, 204f, 731. See also Midsh aft tibia an d fibula fractures occurrence of, 570 Complem ent activation pathways, 120 –121, 120f Complex regional pain syndrom e (CRPS) classification of, 641 differen tial diagn osis of, 641 path ophysiology of, 641 presen tation / physical exam in ation of, 641 radiograph ic fin din gs/ special studies of, 641 treatm en t of, 641 Complex repetitive ischarges (CRDs), 67 Compound m uscle action potential (CMAP), 62, 62f Compression fractures, x-ray of a stable, 449f. See also Upper cervical spin e traum a Compressive neuropathies, 625 –626 Computed tom ography (CT), 46 –47 and calcaneal fractures, 46, 48f of cervical radiculopathy, 462 of cervical spin e, 441 of coron oid fractures, 568, 569f of distal h um eral fractures, 563, 563f

of fem oral h ead fractures, 671, 671f of fem oral n eck fractures, 675 helical CT, 46 of h ip an d fem ur, 663 of in tra-articular fracture, 46, 47f of kn ee an d leg in juries, 710 of m etastatic disease, 492 of olecran on fractures, 567 in oncologic settings, 46 –47 for orth opaedic in fection , 81 of radial h ead fractures, 565 of sh oulder, 519 soft-tissue exten sion by, 47 of th oracolum bar traum a, 453 in traum a settings, 46 Concussion, 171, 172f, 173 Conduction block, 70, 70f, 71 location and stim ulation site, 71f Congenital coronary artery abnorm alities, 183 Congenital coxa vara differen tial diagn osis, 329 incidence, 329 path ophysiology, 329 physical exam in ation , 329 presen tation , 329 radiograph s, 329 treatm en t, 329 –330, 330f Congenital dislocation of radial head, 348, 349f Congenital hand disorders classification of, 651 duplication , 652 em bryology of, 651 failure of differen tiation , 652 failure of form ation , 651 –652 in ciden ce an d etiology of, 651 treatm en t of, 651 Congenital m uscular torticollis (CMT), 382 –383, 383f Congenital myotonic dystrophy, 258 Congenital pseudarthrosis of clavicle, 347, 347f Congenital pseudarthrosis of tibia (CPT), 240, 337 Congenital radioulnar synostosis, 349 Congenital spinal anom alies, 371 differen tial diagn osis, 374 history and physical exam in ation, 372 incidence, 372 path ophysiology an d classification , 371 –372, 373f presen tation , 372 radiograph s, 374, 374f special tests for, 374 MRI for intraspinal anom aly, 374, 375f treatm en t of, 374, 376 –377 h em ivertebra excision , 376, 377f risk of progression , 374, 376t surgery, 376 –377 Congenital trigger thum b, 350 –351 Congenital vertical talus (CVT), 341 –342, 341f, 342f Continuous passive m otion (CPM) m achine, usage of, 746 Coracoacrom ial (CA) ligam ent, 502

803

Coracoclavicular (CC) ligam ents, 504 Coracoid, role of, 502 Corneal abrasion, 174 –175, 175f Coron ary artery disease, 183 –184 Coron ary ligam ents, 697 Coron oid fractures, 567 –568, 571. See also Elbow classification , 568 differen tial diagn osis, 568 injury, m echan ism of, 568 O’Driscoll classification of, 568f patien ts presen tation , 568 physical fin din gs, 568 radiograph ic evaluation , 568 Regan an d Morrey classification of, 568f special studies, 568 treatm en t, 568 –569 Corrosion, 27 Cortical bone, 15, 24, 207 Corticosteroids, 143 for Duch en n e m uscular dystrophy, 258 role of, 580 Costoclavicular ligam ent, 505 Cramps, 68 Craniocervical dissociation, 443 Crankshaft phenom enon, 366 C-reactive protein (CRP), 82, 125, 494, 558 Creatine, 189 Creeping substitution, 695 Crepitus, definition of, 705. See also Kn ee and leg injuries Crista supinatorum , 550 Cross-finger flap, usage of, 613, 615f Cross-section al study, 33, 34 Cruciate anastom osis, 657 –658. See also Hip and fem ur Cruciate ligam ents, 699 Cruciate pulleys, 587 Crystal-induced arthropathies, 133 calcium pyroph osph ate deposition disease (CPDD), 135 gout, 133 –135 hydroxyapatite deposition disease (HADD), 135 Crystalline arthropathy differen tial diagn osis of, 640 path ophysiology/ classification of, 639 presen tation / physical exam in ation of, 640 radiograph ic fin din gs/ special studies of, 640 treatm en t of, 640 Cubital tunnel syn drom e, 572, 630 differen tial diagnosis of, 581, 630 pathophysiology/ classification of, 581, 629 –630 physical exam ination in, 581 physical exam in ation of, 630 presentation of, 581, 630 radiographic fin din gs of, 581 special studies in , 630 special tests in, 581 treatm ent of, 581 –582, 630 –631 ulnar nerve transposition, 581 –582, 582f Cubitus varus, 557f

804

Index

Cuboid fractures, 777 –778 Cuff tear arth ropathy, 543, 544. See also Glen oh um eral (GH) join t glen oid replacem en t in , 546 Curly toe, 346 Cyclist’s knee. See Run ner’s knee Cyclobenzaprine (Flexeril), 130 Cyclooxygenase-2 inh ibitors, 687

D

Dash board in juries, 666. See also Hip dislocation s Data, 29 distribution , 30 n onparam etric data, 30 n orm al distribution, 30, 30f param etric data, 30 types of, 29, 30 bin ary variable, 30 categorical variables, 30 con tin uous variables, 30 ordin al variables, 30 Deep ven ous throm bosis (DVT), 661, 747 Dega osteotomy, 308 Dega / San Diego pelvic osteotomy, 245, 245f Degen erative arth ritis differen tial diagn osis of, 633 occurren ce of, 633 path ophysiology of, 633 presen tation / physical exam in ation of, 633 radiograph ic fin din gs of, 633 special studies in , 633 treatm en t of, 633 Degen erative join t disease (DJD), 576 osteoarth ritis, 577 –578 posttraum atic arth ritis, 578 –579 rh eum atoid arth ritis, 576 –577 Dehydroepian drosteron e, 190 Delpach law, 9 Delta, 36 Deltoid m uscle, 509 atrophy of, 514 Den is classification of sacral fractures, 218, 219f de Quervain ten osyn ovitis anatomy pertinent to, 645, 645f differen tial diagn osis of, 645 path ophysiology of, 644 physical exam in ation of, 644 presen tation of, 644 radiograph ic fin din gs of, 645 treatm en t of, 645 Desm oid tum ors, 160 –161 Developm en tal dysplasia of h ip (DDH), 299, 653 classification , 300, 301f diagn ostic studies, 303 –306 acetabular index, 305 arthrography, 305 –306, 305f, 306f cen ter–edge an gle, 305, 305f MRI, 305 radiograph ic lin es, 303f, 304 ultrason ography, 303 –304, 303f differen tial diagn osis, 306 incidence, 299

path ophysiology, 299 –300, 300f physical exam in ation , 300 –303 presen tation , 300 treatm en t, 306 birth to 12 m on th s, 306 –307, 306f, 307f residual an d late-presenting dysplasia, 309 –312, 309f, 310f, 311f, 312f walkin g age, 307 –309, 309f Diabetic foot ch arcot arth ropathy of, 785 path ophysiology an d classification of, 784 –785 physical exam in ation of, 785 presen tation of, 785 radiographic fin din gs of, 785 Sem m es–Wein stein m on ofilam en t testing for, 785 special tests for, 785 treatm en t of, 785 –786 Diaphyseal cortex, of lon g bon e, 15f Diaphyseal fem ur fractures, 424 –425 treatm en t for ch ildren between ages of 1 an d 6 years, 425 for ch ildren less th an 1 year, 425 extern al fixation , 425 flexible in tram edullary n ailin g, 425, 426f for older adolescen ts, 425, 427, 427f for sch ool-aged ch ild, 425 Diaphyseal forearm fractures, 420 com plete fractures, 420 green stick fractures, 420 plastic deform ation , 420 treatm en t m eth od, 420, 421f Diaphyseal fractures, 212 –213 fixation m eth ods bridge platin g, 214, 214f extern al fixation , 213 –214 internal fixation, 214 skeletal traction , 213 splinting an d castin g, 213 Diarth rodial join t, 501, 700 degen erative arth ritis in , 633 Diastroph ic dysplasia, 274 –275, 274f, 275f 1,25-dihydroxy-vitam in D, 97, 98 Diplegia, 241 Direct deoxyribon ucleic acid an alysis, 271 Discoid m en iscus, 332 –334, 333f Disease-m odifyin g an tirh eum atic drugs (DMARDs), 639, 784 Distal biceps ten don rupture, 574 classification of, 575 differen tial diagn osis, 575 injury, m echanism of, 575 m agn etic reson an ce im age of, 576f physical fin din gs, 575 presen tation , 575 radiographic evaluation, 575 special studies, 575 treatm en t of, 575 –576 Distal fem oral physeal fractures, 427, 428f Distal fem ur fractures classification of, 710 com plication of, 712 differen tial diagn osis of, 711

m echanism of injury, 711 physical exam in ation of, 711 presen tation of, 711 radiographic exam ination of, 711 relevan t an atomy of, 711 special tests for, 711 treatm en t of, 711 –712, 711f Distal forearm fractures. See also Han d an d wrist classification of, 608 m echanism of injury, 608 presen tation an d physical exam in ation , 608 radiographic findings, 608 treatm en t of, 608 Distal h um eral physeal fracture, 415 –416, 416f Distal h um erus, 549 fractures (See also Elbow) classification , 561 differen tial diagn osis, 563 injury, m echanism of, 561 Orthopaedic Traum a Association classification of, 561, 562f patients presentation, 561 physical fin din gs, 561 –563 radiographic evaluation, 563 special studies, 563 treatm en t of, 563, 564f Distal in terph alan geal (DIP) join ts, 586, 587f, 633, 757 radiograph and schem atic of, 634f Distal ph alan geal fractures classification of, 596 exten sion block pin n in g tech n ique in , 597f m echanism of injury, 596 presen tation an d physical exam in ation , 596 radiographic findings, 596 treatm en t of, 596 –597, 596f Distal radiouln ar join t (DRUJ), 584, 609 arthritis differen tial diagn osis of, 638 path ophysiology/ classification of, 638 physical exam in ation of, 638 presen tation of, 638 radiographic findings of, 638 Sauve –Kapan dji procedure in , 638 treatm en t of, 638 compon en ts of, 586f Distal radius fractures, 420, 422. See also Han d an d wrist bicortical fractures, 420, 422f buckle (torus) fractures, 420 classification of, 606 –607 m echanism of injury, 607 Melone classification of, 606, 606f presen tation an d physical exam in ation , 607 radiographic findings, 607 treatm en t of, 607 –608 volvar, 607, 607f Doppler sign alin g device, 200 Dorsal in tercalated segm en t in stability (DISI), 610

Index Dorsalis pedis artery, 759 Dorsal lip fractures, 777. See also Navicular fractures Dorsal radiocarpal ligam en ts, 585f Down syn drom e (trisomy 21) in ch ildren , 383 –384 path ophysiology, 280 presen tation an d physical exam in ation , 280 –281, 281f radiograph s, 281 screen in g tests for, 281 treatm en t, 281 –282 h ip disorders, m anagem ent of, 282, 282f Dual en ergy x-ray absorptiom etry (DEXA), 58, 101 for diagn osis of osteoporosis, 103 –104 Duch en n e m uscular dystrophy, 2, 256 diagn ostic studies, 257 differen tial diagn osis, 257 –258 history an d physical exam ination, 256 –257 path ophysiology, 256 presen tation an d n atural h istory, 256 treatm en t, 258 Dull ach e, 546. See also Adh esive capsulitis Duloxetin e, 130 Dupuytren disease ch aracterization of, 641 Grayson ligam ent, 642, 642f palm ar an d digital fascia in , 643f path ophysiology of, 641 –642 physical exam in ation of, 642 presen tation of, 642 radiograph ic fin din gs of, 642 treatm en t of, 642 –643 Dyn am ic compression plate, 212 Dyn am ic tech n ique, ultrason ograph ic m ethod in DDH, 304 Dyskin esia, 241 Dystroph in , 256

E

Ecchym oses, 514 Eh lers–Dan los syn drom e, 284 Eikenella corrodens, 650 Elastic cartilage, 11 Elastic m aterials, 21, 22f Elbow arteries an d nerves of, 555f dislocation , 569 –571 fun ction al an atomy of lateral uln ar collateral ligam en t complex, 552f ligam en ts, 550 –551, 551f m uscles, 551 –552, 553f n eurovascular structures, 552 –558, 555f osteology, 549 –550, 550f syn ovial fluid/ laboratory studies, 558 fun ction of, 549 traum atic in juries to fractures, 558 –569 in stability, 569 –571 ligam en t an d ten don in jury, 571 –582 Electrodiagn ostic m edicin e, 61

Electrodiagn ostic testin g, 61 clin ical application s, 73, 76 m onon europathies, 73 –74 plexopath ies, 76 polyn europathy, 74 –75 radiculopath ies, 75 –76 electromyography (EMG), 66 con cen tric n eedle, use of, 66 insertional activity, 66 m onopolar needle, use of, 66 MUAP, evaluation of, 68 –69 m uscle at rest, 66 –68 needle EMG steps, 66 patien t preparation , 66 single-fiber EMG, 69 –70 nerve con duction studies (NCS), 61 late responses, 63 –64, 63f, 64f m otor NCS, 62 –63, 62f patien t preparation for, 62 pitfalls of, 64 –66 repetitive nerve stim ulation , 64 sensory NCS, 62, 62f nerve reaction to injury, 70 –73 Electromyogram , 560, 669 usage of, 522 Electromyography (EMG), 200, 462 –463, 626 Elson test, role of, 619 Em bryology, orth opaedic intram em branous and enchondral ossification , 2 –3 joints, developm ent of, 4 m esoderm al differentiation, 4 neurom uscular developm en t, 3 –4 En ch on dral ossification , process of, 3 En ch on drom a, 150 –151, 150f En dobon e, 268 En dplate spikes, 66 –67 En n ekin g Surgical Stagin g System , for bon e sarcom as, 147t En teropath ic arth ritis, 133 Eosin oph ilic gran ulom a, 152, 153f Eosin oph ils, 120 Eph edrin e, 190 Epidem iology an d biostatistics, in orth opaedic surgery causality, 33 data, 29 distribution , 30 types of, 30 defin ition s of, 29 health outcom es research, 38 hypoth esis testin g, 35 –37 inference, 31 errors in , 31 –32 selection bias, 31 con trollin g of, m eth ods for, 32 study design an d eviden ce-based m edicine, 33 –34 study types, 34 –35 test ch aracteristics, 37 –38 variables, 29 Epidural h em atom a, 173, 174f Epiphyseal vessels, 9 Epiphysis, 3 Equin ovarus foot, 246, 246f

805

Erb palsy, 348 Eryth em a ch ron icum m igran s (ECM) rash , 292, 292f Eryth rocyte sedim en tation rate (ESR), 82, 494, 558 Eryth ropoietin (EPO), 190 Essex–Lopresti lesion , 565 Estrogen , in treatm en t of osteoporosis, 106 Etan ercept, 132 Evan s’classification , of in tertroch an teric h ip fractures, 678, 678f Eviden ce-based m edicin e defin ition of, 29, 33 levels of evidence, 33t Ewin g sarcom a, 156 –157, 159f, 489 –490. See also Spin e Excursion distan ce, defin ition of, 692. See also Total h ip arth roplasty (THA) Exercise-in duced bron ch ospasm , 184 –185 Exertion al com partm en t syn drom e com plication s of, 734 differen tial diagn osis of, 734 m echanism of in jury, 734 physical exam in ation of, 734 presen tation of, 734 radiograph ic exam in ation of, 734 special tests for, 734 treatm en t of, 734 Exten sor carpi radialis brevis (ECRB), 552, 587, 588 Exten sor carpi radialis lon gus (ECRL), 587, 588 Exten sor carpi uln aris (ECU), 552, 584 Exten sor digiti m in im i (EDM), 587 Exten sor digitorum brevis (EDB), 66, 758 Exten sor digitorum com m un is (EDC), 552, 587 Exten sor digitorum lon gus (EDL), 758 Exten sor h allucis brevis, 758 Exten sor h allucis lon gus (EHL), 758 Exten sor h ood, defin ition of, 588 Exten sor in dicis proprius (EIP), 587 Exten sor pollicis brevis (EPB), 588 Exten sor pollicis lon gus (EPL), 588 Exten sor ten don in juries classification of, 617 –618 m allet fingers, 617, 620f m echanism of in jury, 618 physical exam ination, 618 –619 radiographic fin din gs, 619 special studies, 619 treatm en t of, 620 zon es of, 620f

F

Facet subluxation an d dislocation , 451 –452. See also Upper cervical spin e traum a bilateral facet subluxation , 452f MRI in, 451 Facioscapuloh um eral dystrophy, 258 Fam ilial hypoph osph atem ic rickets, 261 Fasciculation s, 67 Fat em bolism syn drom e, 205 Fatigue of implan t, 27

806

Index

Felon path ophysiology of, 647 presen tation / physical exam in ation of, 647 radiograph ic fin din gs of, 647 treatm en t of, 647 Fem ale ath letic triad, 188 Fem oral h ead fractures, 669 classification of, 670 complication s of, 672 CT scan for, 671 differen tial diagn osis of, 672 m echanism of in jury, 670 –671 patien ts presen tation in , 671 physical exam in ation of, 671 Pipkin ’s classification of, 670, 670f radiograph ic exam in ation of, 671, 671f special tests in , 671 –672 treatm en t of, 672 vascular supply of, 658 –659, 659f (See also Hip an d fem ur) Fem oral n eck fractures anteroposterior radiograph of, 676f, 677f classification of, 672 –673 complication s of, 677, 677t CT scans of, 675 differen tial diagn osis of, 675 –676 fem oral h ead –n eck jun ction, 675, 675f garden align m en t index in, 675, 676f Garden classification of, 672, 673f m echanism of in jury, 673 MRI of, 675 patien ts presen tation in , 673 –674 Pauwels’classification of, 672, 674f, 675f physical exam in ation of, 674 –675 radiograph ic exam in ation of, 675 special tests in , 675 treatm en t of, 676 –677 Fem oral sh aft fractures classification of, 683 –685 differen tial diagn osis of, 685 intram edullary nails usage in, 686 m echanism of in jury, 685 physical exam in ation of, 685 presen tation of, 685 radiograph ic exam in ation of, 685, 685f special tests for, 685 treatm en t of, 685 –687, 686 Win quist –Han sen ’s classification for, 684, 684f Fem oroacetabular impin gem en t, 662 Fibrillation poten tials, 67, 67f Fibrillin , 282 Fibroblast growth factor receptor-3 (FGFR-3), 270 Fibrocartilage, 11 Fibromyalgia, 130 Fibromyxosarcom a, 162 Fibrosarcom a, 161 Fibrous dysplasia, 155, 155f

Fibular h em im elia, 288 Ach term an –Kalam ch i classification system , 288, 288f differen tial diagn osis, 289 path ophysiology, 288 presen tation an d physical exam in ation , 288 –289, 288f radiographs, 289 treatm en t, 289 Fieldin g’s classification , of subtroch an teric fem ur fractures, 681 Figh t bite, 650. See also Bite woun ds Fin ger extensor m ech anism of, 590f pulley system of, 588f Fin ger replan tation , in dication s an d con train dication s for, 624t Fish er’s exact test, 30, 36 Fixed-an gle plates, 212 Flexible flatfoot (pes plan us), 342 –343, 342f, 343f Flexion –distraction in juries, cause of, 456 Flexor carpi radialis (FCR), 552, 584 Flexor carpi uln aris (FCU) ten don , 583, 585 Flexor digiti m in im i brevis (FDMB), 590 Flexor digitorum accessorius, 758 Flexor digitorum brevis (FDB), 758 Flexor digitorum lon gus (FDL), 757 Flexor digitorum profun dus (FDP), 584 Flexor digitorum profun dus ten don , repair of, 619f Flexor digitorum superficialis (FDS), 552, 584 Flexor h allucis brevis (FHB) ten don , 754 Flexor h allucis lon gus (FHL), 753 Flexor pollicis brevis (FPB), 589 Flexor pollicis lon gus (FPL), 584 Flexor sh eath s, 587 Flexor ten don in juries, 613 –614 classification an d m ech an ism of in jury, 615 –616 differen tial diagn osis, 616 jersey fin ger, 615, 616f path ophysiology, 614 –615 presen tation an d physical exam in ation , 616 quadregia effect, 617 radiograph ic fin din gs, 616 special studies, 616 treatm en t of, 616 –617 Fluorin e-18-fluorodeoxyglucose PET (FDG-PET), 58 in periprosthetic in fections diagnosis, 92 Fluoroquin olon es, 80, 81t Focal demyelin ation , 71 Folic acid, 128 Foot an d an kle anterior drawer test of, 760 atraum atic conditions of ach illes ten don pathology, 787 –788 acquired adult flatfoot deform ity, 790 –791 ch arcot arth ropathy, 786 –787 diabetic foot, 784 –786 hallux rigidus, 795 –797

h allux valgus, 793 –795 m orton neurom a, 797 –798 peron eal ten don path ology, 789 –790 plan tar fasciitis, 792 –793 rheum atoid foot, 782 –784 tarsal tun n el syn drom e, 788 –789 CT scans in, 761 fun ction al an atomy of ankle join t, 754 –756 foot, extrin sic m uscles of, 757 –758 foot, in trin sic m uscles of, 758 –759 gait an alysis, 759 –760 interphalan geal joints, 757 m etatarsophalangeal join ts, 757 m idfoot join ts, 756 –757 n eurovascular structures, 759 osteology, 753 –754 subtalar join t, 756 tarsom etatarsal join ts, 757 tran sverse tarsal join t, 756 in version stress tests of, 760 m edial deltoid ligam ent complex, 755f MRI in, 761 os calcis in , 753 os tibiale extern um in , 754 os trigon um in , 753 problem s, evaluation of h istory, 760 im aging, 760 –761 physical exam ination, 760 susten taculum tali in , 753 traum atic in juries to achilles tendon ruptures, 769 –770 ankle fractures, 763 –767 ankle sprains and syndesm osis injuries, 767 –769 calcan eus fractures, 774 –777 cuboid fractures, 777 –778 lisfranc injuries, 778 –780 m etatarsal fractures, 780 –782 n avicular fractures, 777 osteoch on dral lesion s of talus, 772 –774 ph alan geal fractures, 782 pilon fractures, 761 –763 sesam oid fractures, 782 talus fractures, 770 –772 Foot fractures, in ch ildren , 433 Foot progression an gle, n orm ative values for, 237f Foram in al sten osis, 467 Force defin ition of, 20 form ula for, 21 and m om ent, 20 –21 types of compressive force, 20 sh earin g force, 20 tensile force, 20 un it of, 21 vector analysis technique, 20, 20f Force couple, 21 defin ition of, 509 (See also Sh oulder) Forearm deep m usculature of, 591 and han d, m uscles of, 589f Forest plots, 35

Index Fourier tran sform ed in frared spectroscopy (FTIR), 101 Fracture classification system s, 206 –207 AO/ O TA system , 206, 206f Garden classification, for fem oral n eck fractures, 206 Hawkin s classification , for talus fractures, 206 Sch atzker classification , for tibial plateau fractures, 206 utility of, 206 Fracture-dislocation s, 201, 203f Fracture fixation in dication s for, 210 m ethods external fixation, 210, 212f in tern al fixation , 210, 212, 213f splin tin g an d casting, 210 traction , 210 Fracture In terven tion Trial, 106 Fracture Risk Assessm en t Tool (FRAX), 104 –105 Fran kel gradin g system , in SCI, 436 Freiberg in fraction , 346 Frostbite, 187 Frozen sh oulder, 546 diagn osis of, 547 Fun nel plots, 35

G

Gait analysis, of hip, 659. See also Hip and fem ur Galeazzi fracture, 608 Galeazzi test, 302, 302f Galleazi test, 242 Gallium -67 citrate, 56 Gallium scann ing, in spine in fections, 494 Galveston technique for pelvic fixation, 370, 372f Gam ekeeper’s thum b, 54 m echan ism of injury, 601 presen tation an d physical exam in ation , 601 radiograph ic fin din gs, 601 special studies, 601 sten er lesion in , 601, 601f treatm en t of, 601 Gam m a cam eras, 55 Ganz periacetabular osteotomy, 310, 310f Garden alignm ent index, in fem oral neck fractures, 675, 676f Garden classification, of fem oral neck fractures, 672, 673f Gardn er-Wells tongs, usage of, 437 Gastrocnem ius recession, 247, 247f Gaussian (norm al) distribution, 30, 30f con fiden ce in terval, 30 kurtosis, 30, 31f m ean, 30 m edian, 30 m ode, 30 skewn ess, 30, 31f Genetics, and m usculoskeletal anom alies, 1 categories of gen etic diseases, 1 ch rom osom al abn orm alities, 2 gen etic defects, 1

Mendelian inheritance, pattern s of, 1 autosom al dom inant, 1, 2f autosom al recessive, 1, 2f X-lin ked dom in an t con dition s, 1 X-lin ked recessive con dition s, 1 –2, 2f polygen ic in h eritan ce, 2 Gaussian curve, 2, 2f Genu varum , in children, 235, 236f, 237f Giant cell tum ors, 154 –155, 154f Gilula lin es, 611, 612f. See also Carpal instability GLA proteins, 19 Glasgow com a scale, 401 Glen ohum eral (GH) joint, 501, 502f, 503 –504, 509 –511 arthritis, in shoulder cause of, 543 differen tial diagn osis, 545 path ophysiology an d classification , 542 –544, 543f, 544f patien t presen tation , 544 physical exam in ation , 544 radiograph ic fin din gs, 544 –545 special tests, 545 treatm en t of, 545 –546, 545f, 546f glen oid labrum role in , 505f instability, in sh oulder classification , 528 –529 differen tial diagn osis, 532 laxity of, 531, 531f m echanism of injury, 529 patien ts presen tation , 529 physical exam in ation , 529 –531 positive sulcus sign , 531f radiograph ic exam in ation , 531 –532 special studies, 532 supine test, 530 treatm en t of, 532 –533, 532f velpeau view, 532, 532f Glen ohum eral rotation, m easurem ent of, 515 Glen oid bone loss, 546 Glucocorticoids, 10 Godfrey test, for PCL, 707 Gout, 133 –135 Gowers sign, 257, 257f Gray, 59 Grayson and Clelan d ligam ents, relationsh ip of, 595f Gross Motor Function Classification System (GMFCS), of CP, 241, 242f Growth horm one, 10 Growth plate, 4 –5 biom ech an ics of, 10 blood supply of, 9 closure of, 10 con trol of, 9 –10 hypertroph ic zon e, 7 –8 m etaphysis, 8 –9 pattern s of growth , 9 physis, 5 –7, 8f proliferatin g zon e, 7 resting (reserve) zone, 7 structure an d blood supply of, 8f zone of provision al calcification , 8 Gunstock deform ity, 412, 412f

807

Gustilo an d Anderson classification , of open fractures, 199 Guttm ann’s guidelines, SCI treatm ent, 438 Guyon canal, 591

H

Haglund deform ity, 787 Hallux rigidus exam in ation of, 796 NSAIDs in , 796 path ophysiology an d classification of, 795, 796f presen tation of, 796 radiographs of, 796 treatm en t of, 796 –797, 796f Hallux valgus differen tial diagn osis of, 795 path ophysiology an d classification of, 793 –794 physical exam in ation of, 794 presen tation of, 794 radiographic fin din gs of, 794 –795 sesam oid subluxation in , 794f treatm en t of, 795, 795f Halo brace im m obilization, in SCI, 437 Ham ate fractures, 605f. See also Han d and wrist classification of, 605 m echanism of injury, 605, 605f presen tation an d physical exam in ation , 606 radiographic fin din gs, 606 treatm en t of, 606 Ham ulus, definition of, 583 Han d and wrist anatomy of, 583 bon e an d ligam en t carpus, 583 –584, 584f, 585f carpus, 601 –612 con gen ital h an d deform ities, 651 –652 fractures an d dislocation s, 596 –601 han d in fection s, 646 –651 inflam m atory arthritis, 638 –643 intrinsic hand m uscles, 588 –590 m etacarpal and phalangeal structures, 584 m uscles and tendons extrin sic exten sors, 587 –588 extrin sic flexors, 584 –587 nerve an atomy of, 594 –595 non traum atic in juries to, 625 –638 patien t evaluation of, 595 –596 soft tissue in juries, 612 –625 tendinopath ies, 644 –646 traum atic in juries to, 596 vascular, 591 –594 Han d dyn am om eters, 255 Han d infections differen tial diagn osis of, 646 history/ physical exam in ation of, 646 path ophysiology of, 646 presen tation of, 646 radiographic fin din gs of, 646 special studies in , 646 treatm en t of, 646 –647 Han d injuries, in children, 422

808

Index

Hand stiffness classification of, 640 intrinsic tightness test in, 640, 640f presen tation / physical exam in ation of, 640 –641 radiograph ic fin din gs/ special studies of, 641 treatm en t of, 641 Hangm an ’s fracture, 395, 396f, 446 –448 incidence of, 446 Levin e an d Edwards classification of, 447, 447f treatm en t of, 447 –448 Type IIa traum atic spondylolisthesis, 448f Hawkin s im pin gem en t sign, 537, 538f. See also Sh oulder Heat illn ess, 185 –186 fluid replacem en t guidelin es, 186t heat cramps, 186 heat exh austion , 186 heat rash , 186 heatstroke, 186 heat syn cope, 186 and hydration , 186 preven tion of, 186 Hem an giom as, 155, 488 –489 jail house vertebra of, 156f Hem iarthroplasty, 546 in proxim al hum erus fractures treatm en t, 525 Hem iarthroplasty for displaced fem oral n eck fracture, 212, 213f Hem iplegia, 241 Hem oph ilia, 2 Herniated disk, defin ition of, 465, 474. See also Cervical spine; Lum bar spine Herpetic whitlow differen tial diagn osis of, 648 infection, 648f path ophysiology of, 647 presen tation / physical exam in ation of, 647 radiograph ic fin din gs/ special studies of, 648 treatm en t of, 648 Heterotopic ossification (HO) form ation , 563 Heulter-Volkm an n law, 9 Hibb angle, 255 High ankle sprain s, 767 High tibial osteotomy (HTO), 742 Hilgenreiner epiphyseal angle (HEA), 329, 330f Hilgenreiner lin e, 304 Hill-Sachs lesion , of hum eral head, 529, 530f Hip and fem ur, 656f, 657f anatomy of em bryology of h ip, 653 pelvis an d proxim al fem ur, osteology of, 653 –655 soft tissue an d m usculature in hip joint, 655 arterial supply, 658f assistive device usage, 660 atraum atic hip condition s

hip arth ritis, 687 –688 hip arth ritis, treatm ent of, 688 osteon ecrosis, 695 –696 total hip arth roplasty, 688 –695 com pon en ts of, 654f fem oral h ead an d n eck, vascular anatomy of, 660f hip, biom echan ics of gait analysis, 659 joint reaction force, 659 hip joint, role of, 653 neurovascular anatomy of h ip cruciate an astom osis, 657 –658 fem oral h ead, vascular supply of, 658 –659 greater an d lesser sciatic foram en , 655 –657 sciatic n erve, 657 patien t evaluation anteroinferior impingem ent test in, 662 clin ical h istory, 659 –661 CT scan im aging in, 663 Ober’s test in, 662 pelvis an d acetabulum , 663, 664f, 665f physical exam in ation , 661 –662 radiographic evaluation, 662 –666, 663f Thom as test in, 662, 662f traum atic in juries to fem oral h ead fractures, 669 –672 fem oral n eck fractures, 672 –677 fem oral sh aft fractures, 683 –687 hip dislocation s, 666 –669 intertrochanteric h ip fractures, 677 –680 subtroch anteric fem ur fractures, 680 –683 Hip arth ritis, 687 –688 cyclooxygen ase-2 in h ibitors in , 687 intra-articular glucocorticoid injection s, usage of, 687 treatm en t, n on arth roplasty altern atives for, 688 hip arth rodesis, 688 hip arth roscopy, 688, 688f osteotom ies, 688 Hip arth rodesis, usage of, 688 Hip arth roscopy, usage of, 688, 688f Hip dislocation s, 669f Allis reduction tech n ique for posterior, 668, 668f classification of, 666 classification sch em es for posterior, 666t com plication s of, 669, 669t com puted tom ography scan of, 667 –668, 668f differen tial diagn osis of, 668 Levin ’s classification of posterior an d anterior, 666t m echanism of injury, 666 –667 MRI in, 668 orth opedic in juries in , 667t patien ts presen tation in , 667 physical exam in ation of, 667

radiographic evaluation of, 667 –668 sciatic n erve in juries in , 667 special tests, 668 treatm en t of, 668 –669 Hip fractures, pediatric, 423 complication of, 424, 425f Delbet classification for, 423, 423f type I fractures, 423 –424 type II fractures, 424 type III fractures, 424, 424f type IV fractures, 424 Hip osteotom ies, 688 Hip rotation , m easurem en t of, 237, 238f Hitch h iker th um b, 274 Hom ocystin uria, 284 Hooke’s law, 21 Hook of th e h am ate, 583 Horn blower sign , 517 Horsesh oe abscess, 648 Howard Steel, 314 Hum an growth h orm on e (HGH), 190 Hum eral sh aft fractures, 405, 407f. See also Elbow classification , 558 differen tial diagn osis, 560 m echanism of, 558 –559 patien ts presen tation , 559 physical fin din gs, 560 and radial nerve injuries, 405 radiographic evaluation, 560, 560f special studies, 560 treatm en t, 560 –561, 562f Hyalin e cartilage, 11, 549 Hyaluron ic acid, usage of, 741. See also Osteoarth ritis (OA), of knee Hydroxyapatite deposition disease, 135 Hydroxych loroquin e, 128 25-hydroxy-vitam in D, 98 Hypertrophic cardiomyopathy, 183, 184f Hypotherm ia, 187 Hypoth esis testin g clin ical sign ifican ce, 36 and m easures of effect, 36 –37 h azard ratio, 36 odds, 36 odds ratio, 36 probability, 36 relative risk, 36 power an alysis, 36 p value, 35 statistical sign ifican ce, 35 –36

I

Iatrogenic injury, 573 Ice m assage, in m edial tibial stress syn drom e, 734 Idiopathic adhesive capsulitis, phases of, 546 Idiopathic scoliosis adolescen t idiopath ic scoliosis, 359, 360f classification , 358 –359 differen tial diagn osis, 363 h istory an d physical exam in ation , 360 –361, 361f n atural h istory, 363 –364 path ophysiology, 358, 359f

Index presen tation , 359 –360, 361f radiograph ic evaluation , 361 –362, 362f, 363f special tests for, 363 treatm en t, 364 –367 anterior fusion with anterior instrum entation, 366, 368f bracin g, 365 –366, 366f posterior spin al in strum en tation an d fusion , 366, 367f serial castin g, 364, 364f surgery, 366 use of growin g in strum en tation , 364, 365f Idiopath ic toe-walkin g, 339 –340 Iliotibial (IT) ban d, 662, 700 Im agin g, in orth opaedic surgery bon e den sitom etry, 58 com puted tom ography, 46 –47 con ven tion al arth rography, 45 –46 m agnetic resonance im agin g, 47 –53 n uclear scin tigraphy, 54 –58 plain radiography, 39 cervical spin e, 39 –, 39 –40 foot an d an kle, 43 –45 h an d an d wrist, 41 –42 kn ee, 43 pelvis an d h ip, 42 –43 sh oulder, 40 –41 and radiation exposure considerations, 58 –59 ultrason ography, 53 –54 Im m un e system , 117 com pon en ts of, 117 –118 antigen -presenting cells, 118 B cells, 119 com plem en t system , 120 –121 im m un oglobulin s, 119 –120, 119t m onocyte/ m acrophages, 120 n eutroph ils, 120 T cells, 118 –119 im m un oregulation and im m un opathology, 121 type I, 121 type II, 121 type III, 121 type IV, 121 n on specific im m un e respon se, 117 specific im m un e response, 117 Im m un e toleran ce, 118 Im m un oglobulin s, 119 –120, 119t Impin gem en t syn drom e, 513, 540 IM rod, 212 In dium -111-labeled leukocyte scannin g, in spin e in fections, 494 In dom eth acin , 132 In fectious arth ritis bacterial agen ts, 137 –138 n on bacterial agen ts, 138 viral agents, 138 In feren ce, 31 defin ition of, 29 errors in, 31 bias, 31 ch an ce, 32, 32t con foun ders, 31 –32, 32t m easurem en t bias, 31

m issing data, 31 publication bias, 31, 32f recall bias, 31 sampling bias, 31 selection bias, 31 random error, 31 system atic error, 31 Inferior transverse ligam en t (ITL), 756f Inflixim ab, 132 Infraspinatus m uscle, role of, 508 Intercalary segm en t, 583 Interlukin-6 (IL-6), 91 Interm alleolar distan ce, m easurem en t of, 237, 238f Internal tibial torsion , in ch ildren , 235, 236f Internation al Com m ission on Radiological Protection (ICRP), 59 Internation al n orm alized ratio (INR), 747 Internation al Society for Clin ical Den sitom etry (ISCD), 104 Interosseous m em bran e (IOM), 756f Interosseus m uscles, in h an d and wrist, 588 Interphalan geal join ts, 757 Intersection syn drom e, 646f differen tial diagn osis of, 646 path ophysiology of, 645 presen tation / physical exam in ation of, 645 radiographic findings of, 646 treatm en t of, 646 Intertrochan teric h ip fractures, 677 –678, 679, 680f ceph alom edullary device usage in , 679, 680f classification of, 678 clin ical presen tation of, 678 complication s of, 680 differen tial diagn osis of, 679 Evans’classification of, 678, 678f m echanism of injury, 678 physical exam in ation of, 678 –679 radiographic findings of, 679 sliding screw plate device usage in , 679, 679f special tests in , 679 treatm en t of, 679 –680 Intra-articular corticosteroid injections, usage of, 741. See also Osteoarth ritis (OA), of knee Intram edullary (IM) n ailin g, 561 Intram em bran ous bone form ation, 2 –3 Intrinsic han d m uscles, 588 –590. See also Han d an d wrist superficial an d deep, 592f Involucrum , 88 Isthm ic spondylolisthesis, 477 IT band syn drom e, 702 differen tial diagn osis of, 729 m echanism of injury, 729 Ober test in, 729 patien ts presen tation of, 729 physical exam in ation of, 729 radiographic exam ination of, 729

809

relevant anatomy of, 729 special tests for, 729 treatm en t of, 729

J

Jacoud arth ropathy, 136 Jah ss m an euver, 599 Jersey fin ger, 615, 616f. See also Flexor tendon injuries Jobe test, 516, 516f Join t effusion , detection of, 705. See also Kn ee an d leg in juries Join t reaction forces, in h ip, 659. See also Hip and fem ur Jon es fractures, occurren ce of, 782 Juven ile h allux valgus, 346 Juven ile rh eum atoid arth ritis (JRA), 292 classification an d presen tation , 293, 294f history an d physical exam in ation , 293 –295, 294f laboratory studies, 295 path ophysiology, 292 –293, 293f radiographs, 295, 295f, 296f treatm en t, 295 –296

K

Kien bock disease, 604 Kirsch n er wires, 210, 213f Klein lin e, 314 Klippel–Feil syn drom e, 380 –381, 381f Klisic test, 302 –303 Kn ee, 702f anatomy of, 735 arth rodesis, 744 m odular intram edullary n ail in, 744f biom ech an ics of, 735 –736 dislocation classification of, 718, 719f com plication s of, 720 differen tial diagn osis of, 720 m echanism of injury, 718 –719 patien ts presen tation of, 719 physical exam in ation of, 719 radiographic exam ination of, 719 relevan t anatomy of, 719 special tests for, 719, 720f treatm en t of, 720 injury determ ination , 706 join t, 697 join t with patella, 736f ligam ent evaluation, 706 –708 m echanical an d anatom ic axes of, 737f non traum atic in juries of baker cyst, 730 –731 IT ban d syn drom e, 729 m eniscus tears, 725 –727 osteoch on dritis dissecan s, 729 –730 patellofem oral pain syn drom e, 727 –729 posteroan terior flexion weigh t-bearin g radiograph of, 740f pseudogout, 741f rheum atoid arthritis of, 740f structures of lateral side of, 701f structures of m edial side of, 700f

810

Index

Kn ee (Contd.) traum atic in juries of distal fem ur fractures, 710 –712 patella dislocation, 716 –717 patella fractures, 713 –714 patella ten don ruptures, 715 –716 quadriceps ten don rupture, 714 –715 tibial plateau fractures, 712 –713 Kn ee an d leg in juries ballottem en t test in , 705 ch ron ic patellar in stability, 717 –718 ACL sprain s, 721 –723 kn ee dislocation , 718 –720 LCL sprain, 724 –725 MCL sprains, 720 –721 PCL sprain , 723 –724 evaluation of arthroscopy, 710 CT scans for, 710 h istory, 703 –704 physical exam in ation of, 704 –709 radiograph ic an alysis of, 709 –710 fluid wave test in , 705 fun ction al an atomy of, 697 –703 initial dislocation of, 717 joint effusion, detection of, 705 m edial and lateral condyles, 698f patella articulation , 698f superior surface of tibia, 699f Kn ee–ankle –foot orth oses (KAFOs), 253 Kn ee, osteoarth ritis of causes of, 737 crystallin e arth ropath ies in , 739 –741 hyaluron ic acid usage in , 741 inflam m atory arthritides, 739 intra-articular corticosteroid injections, usage of, 741 lum bar disc disease in, 738 m en iscectomy, 737 non operative treatm ent of, 741 –742 osteoch on dritis dissecan s, 737 path ophysiology of, 737 –738 patien t evaluation clin ical presen tation of, 738 differen tial diagn osis, 739 –741 im aging of, 738 –739 physical exam in ation of, 738, 738f risk factors of, 736 –737 surgical treatm en t of arthroscopy, 742 kn ee arth rodesis, 744 osteotomy, 742 –743 UKA, 743 –744 total knee arthroplasty complication s of, 746 –747 indications, 744 –745 infection, 747 –748 instability, 749 loosening/ wear, 748 –749 outcom es of, 746 periprosth etic fracture, 749 –751 postoperative pain , 747 postoperative recovery, 746 stiffn ess/ arth rofibrosis, 749 surgical procedure, 745 –746 th rom boem bolic disease, 747 varus deform ity in , 742

Kn ock-kn ees, 236, 237f Kruskal–Wallis test, 30

L

The Laboratory Risk In dicator for Necrotizin g Fasciitis (LRINEC), 94 Labrum fun ction of, 654 and tran sverse acetabular ligam ent, 655f Lacertus fibrosis, 552 Lach m an test, for ACL, 706, 707f Lag screws, 210, 212, 213f Lam in a splen den s, 11 Lan gerh an ’s cell h istiocytosis (LCH), 389, 389f. See also Eosin oph ilic gran ulom a Lateral an d m edial epicon dylitis differen tial diagn osis of, 580 Mill test for, 579, 579f path ophysiology an d classification of, 579 physical exam in ation in , 579 –580 presen tation of, 579 radiographic findings of, 580 special studies in, 580 treatm en t of, 580 Lateral circum flex artery (LCA), 298 Lateral collateral ligam en t (LCL), 697, 738 sprain classification of, 724 complication s of, 725 differen tial diagn osis of, 725 m echanism of injury, 724 patien ts presen tation of, 724 physical exam in ation of, 724 radiographic exam ination of, 724 relevan t an atomy of, 724 special tests for, 724 treatm en t of, 725 Lateral con dyle fractures, 412 assessm ent of, 413, 413f complication s, 414 driftin g lateral con dyle fracture, 413, 414f Milch classification of, 412 –413, 412f treatm en t of, 413 Lateral uln ar collateral ligam en t (LUCL), 550 injury classification of, 573 differen tial diagn osis, 573 injury, m echanism of, 573, 573f physical fin din gs, 573 pivot sh ift m an euver for evaluation of, 574f presen tation , 573 radiographic evaluation, 573 treatm en t of, 573 –574 Late respon ses, 63 F-waves, 63, 63f H-reflexes, 63 –64, 64f Lauge–Han sen classification system , of an kle fractures, 763, 764f–765f Laxity, defin ition of, 528. See also Glen oh um eral (GH) join t Leflun om ide, 128

Leg four com partm en ts of, 703f n on traum atic in juries of exertion al compartm en t syn drom e, 734 m edial tibial stress syndrom e, 733 –734 tibial stress fractures, 732 –733 traum atic in juries of m idshaft tibia and fibula fractures, 731 –732 Legg-Calve-Perth es’disease (LCPD), 321, 695 classification system s, 321 Catterall classification, 321, 323f lateral pillar classification, 322, 324f Salter–Th ompson classification , 321 –322 differen tial diagn osis, 325 –326 long-term progn osis, 328 path ophysiology, 321, 322f physical exam in ation , 322 –323 presen tation , 322 radiographs for, 323, 324f, 325f special studies, 324 –325, 326f treatm en t, 326 –328, 327f, 328f Letourn el classification , of acetabular fractures, 222f, 223 Leukocyte scan s, 82 Levator scapula, role of, 511 Levin e an d Edwards classification , of Han gm an ’s fracture, 447, 447f Levin ’s classification , of posterior an d anterior hip dislocations, 666t Lich tm an classification system , 604 Lift-off test, 517, 518f Ligam en t, 25 Ligam en t recon struction ten don interposition (LRTI), 636 postoperative radiograph of, 636f Lim b girdle m uscular dystrophy, 257 –258 Lim b len gth discrepan cy, 351 etiology, 351 evaluation, 351 –353, 352f, 353f treatm en t, 353 –356 extern al fixator, use of, 355, 356f growth-rem ain ing m ethod, 353, 354f guidelines for, 353t Moseley straight-line m ethod, 353, 355f percutan eous epiphysiodesis, 354, 355f rule-of-th um b m eth od, 353 Lim b rotation , n orm al, 3f Limpin g ch ild, 356 diagn osis, 357 –358 diagn ostic studies, 357 differen tial diagn osis, 357t h istory an d physical exam in ation , 356 –357 Lipom as, 160 Lisfran c in juries avulsion fracture, 779 classification of, 778 differen tial diagn osis of, 779 im aging of, 779 lisfranc ligam ent span s, 778f

Index m echanism of injury, 778 physical exam in ation of, 778 –779 presen tation of, 778 Quenu and Kuss classification of, 779f treatm en t of, 779 –780 Loadin g, 23 com pressive, 23 tensile, 23 Lon g h ead of th e biceps ten don (LHBT), 509 Looser’s lin e, 109 –110, 110f Lower Extrem ity Assessm en t Program (LEAP) study, 226 –227 Lum bar disc disease, 738 Lum bar spin e algorithm , 480 –482, 481f adult scoliosis, 484 –486, 486f con servative treatm en t, 482 epidural steroids, 483 radicular pain , causes of, 484 refractory patients with anterior thigh pain , 484 refractory patients with low-back pain , 482 –483 refractory patients with posterior th igh pain , 484 refractory patients with sciatica, 483 –484 h ern iation -clin ical features, 475t h istory of, 473 lum bar spine-clinical entities, 474 –480 physical exam in ation of, 473 –474 referred pain , 473 Lum bar strain , 179 Lun ate, 583 fractures (See also Hand and wrist) classification of, 604 com plication s, 604 m echanism of injury, 604 presen tation an d physical exam in ation, 604 radiograph ic fin din gs, 604 special studies, 604 treatm en t of, 604 types an d fun ction of, 583 Lun atotriquetral sh ear test, 611 Lym e disease, 138 in ch ildren diagn ostic studies, 292 differen tial diagn osis, 292 h istory an d physical exam ination , 292 path ophysiology, 291 –292 presen tation , 292 treatm en t, 292 Lymph om a of bon e, 158, 160f

M

Macrolide antibiotics, 80, 81t Madelung deform ity, 349, 350f Magnetic resonan ce im aging (MRI), 47 –49 Ach illes ten don tear, 54f acute ligam entous injuries, evaluation of, 49 –50 bon e bruises or stress reaction s by, 51 –52, 55f bon e con dition s by, 51, 54f

of ch ordom a, 490, 490f con trast m aterial en h an cem en t, 49 evaluation of soft tissues by, 49 joint surface, evaluation of, 49, 50f kn ee an d leg injuries, 710 kn ee m en iscal deran gem en t on, 49, 51f labral evaluation by, 49, 52f lum bar disc protrusion, 53f m etastatic an d prim ary tum ors of bone, 52, 57f MRI arthrography, 49 m uscle sprains and tears, detection of, 50 –51 open MRI design s, 49 for orth opaedic in fection , 81 –82 for osteomyelitis, 52, 56f of pyogen ic in fection , 494, 495f of scaph oid fractures, 603f of SCI, 437 of sh oulder, 519 for soft-tissue tum ors, 52 –53, 57f spine, evaluation of, 50 for ten don disruption s, 50 Malignant fibrous histiocytom a (MFH), 163 Mallet fingers, 617, 620f. See also Exten sor tendon injuries Malunions, 228, 228f Mam m illary processes, 10 Man gled Extrem ity Severity Score (MESS), 225, 227t Man n –Whitn ey U test, 30, 36 Marfan syn drom e, 183, 282 differen tial diagn osis, 284, 284t path ophysiology, 282 presen tation an d physical exam in ation , 282 –283, 283f radiograph s, 283, 283f, 284f studies for, 284 treatm en t, 284 Martin-Gruber anastom osis, 65 Mason classification, of radial head fractures, 563, 565f. See also Radial head fractures Matrix vesicles, 19 Mayo classification, of olecranon fractures, 565, 566f McCune–Albrigh t syn drom e, 155 McMurray test, in m eniscus tears, 726 Meary angle, 255, 255f Medial circum flex artery (MCA), 298 Medial collateral ligam ent (MCL), 697, 745 composition of, 700 of kn ee, 706 sprains classification of, 720 complication s of, 721 differen tial diagn osis of, 721 m echanism of injury, 720 patien ts presen tation of, 720 Pellegrin i–Stieda sign , 721 physical exam in ation of, 721 radiograph ic exam in ation of, 721 relevant an atomy of, 720 –721 special tests for, 721

811

treatm en t of, 721 valgus stress testin g in , 721 Medial epicondyle, 579 fractures, 414 –415, 415f, 572 Medial epicondylitis, 572 Medial neurovascular structures, anatomy of, 757f Medial patellofem oral ligam ent (MPFL), 717 Medial tibial stress syn drom e differen tial diagn osis of, 734 h eel cord stretch in g in , 734 ice m assage in, 734 m echanism of in jury, 733 physical exam in ation of, 733 presen tation of, 733 radiograph ic exam in ation of, 733 relevant anatomy of, 733 special tests for, 733 treatm en t of, 734 Medial uln ar collateral ligam ent (MUCL), 550 injury classification of, 571 differen tial diagn osis, 572 injury, m echan ism of, 571 m ilking m aneuver for evaluation of, 571, 571f physical fin din gs, 571 –572 presen tation , 571 radiograph ic evaluation , 572 reconstruction , 572, 572f special studies, 572 treatm en t of, 572 –573 Median nerve, 195 role of, 594 Melone classification, of distal radius fractures, 606, 606f Men ingitis, 185 Men iscotibial, 697. See also Kn ee an d leg injuries Men iscus tears blood supply of, 725, 725f classification of, 725 com plication s of, 727 differen tial diagn osis of, 726 McMurray test in, 726 m echanism of in jury, 725 patien ts presen tation of, 726 physical exam in ation of, 726 radiograph ic exam in ation of, 726 relevant anatomy of, 726 special tests for, 726 tear configurations of, 725 treatm en t of, 726 –727 types of, 725, 725f Mesoderm , 3 form ation in h um an em bryo, 5f Meta-analysis, 34, 35 Metabolic bone disease, 97 bon e stren gth , 99, 100f BMD, 99 bon e quality, 99 bon e turn over, 99 –101, 100t, 101f m aterial property of bone, 101 structural properties of bon e, 101 –102

812

Index

Metabolic bone disease (Contd.) calcium –ph osph ate h om eostasis, regulation of, 98 calciton in , 99 parathyroid h orm on e, 98 vitam in D, 98 –99 m in eral hom eostasis and endocrine fun ction in bon e calcium , 97 –98 calcium –ph osph ate h om eostasis, 98 ph osph orus, 98 osteoporosis, 102 –107 Paget’s disease, 112 –114 renal osteodystrophy, 110 –112 rickets an d osteom alacia, 107 –110 Metacarpal and phalangeal structures, of h an d an d wrist, 584 Metacarpal heads, cam shape of, 586f Metacarpal (MC) fractures, 598 ben n ett fracture, 600, 600f classification of, 599 jahss m aneuver for reducing, 600f m echanism of in jury, 599 oblique fracture of, 599f presen tation an d physical exam in ation , 599 radiograph ic fin din gs, 599 rin g an d sm all fin ger, 600f rolando fracture, 600, 600f treatm en t of, 599 –601 Metacarpoph alangeal (MCP) joints, 584, 598 Metals, for implant fabrication ch rom e–cobalt alloy, 25, 26f stain less steel, 25, 25f titan ium -based alloys, 25, 26f Metaphyseal vessels, 9 Metastatic disease, of spine, 491 –493, 491f bracin g, 492 CT scan of, 492 surgery in , 492 Metatarsal fractures, 780 –782 fractures of th e base of fifth , 782f Jon es fractures, occurren ce of, 782 Metatarsophalangeal (MTP) joints, 754, 757 Metatarsus adductus, 340, 340f Meth icillin -resistant Staphylococcus aureus (MRSA), 80 Meth otrexate, 128 Methylprednisolone, in SCI, 438 Metronidazole, 80 –81, 81t Midcarpal in stability, 610 Middle glenohum eral ligam en t (MGHL), 503 Midfoot joints, 756 –757 Midshaft tibia and fibula fractures classification of, 731 compartm en t syn drom e, 731 complication s of, 732 differen tial diagn osis of, 731 m echanism of in jury, 731 patien ts presen tation of, 731 physical exam in ation of, 731 radiograph ic exam in ation of, 731 relevant anatomy of, 731

special tests for, 731 treatm en t of, 732 Mill test, for lateral and m edial epicon dylitis, 579, 579f Milnacipran (Savella), 130 Milwaukee brace, 379 Mineralization, 19 process of in itiation , 19 proliferation ph ase, 19 Miniature endplate potentials (MEPPs), 66 –67 Moberg advan cem en t flap, 613, 614f Modified injury severity scale (MISS), 401, 403t Mom ent, bending m om ent on com pression h ip screw, 20, 21f Monocytes, 120 Mononeuropathies, diagnosis of, 73 m edian neuropathy at wrist, 73 peron eal n europathy at fibular h ead, 74 radial n europathy at hum erus, 74 uln ar n europathy at elbow, 73 –74 Mon on ucleosis, 185 Monteggia fracture–dislocation s, 418 Bado classification , 418, 419f diagn osis of, 418, 419f Monteggia injury, 419, 419f and congenital radial head dislocation , 420, 420f treatm en t of, 418 –419 Morel-Lavallee lesion, 220 Morton neurom a differen tial diagn osis of, 797 path ophysiology an d classification of, 797, 797f physical exam in ation of, 797 presen tation of, 797 special tests for, 797 treatm en t of, 797 –798 Motor unit action potentials (MUAPs), 66, 68 param eters, 68f amplitude, 68 duration , 68 ph ases, 68 recruitm ent, 68 increased, 69, 69f norm al, 68 –69, 69f reduced, 69 Motor units, 68 Motor veh icle accidents (MVAs), 435 Mouth guards, 175 MP joint arthritis, 634 Mucopolysaccharidoses (MPSs), 276 classification , 278, 278t differen tial diagn osis, 280 path ophysiology, 277 presen tation an d physical exam in ation , 278, 278f radiographs, 278 –279, 279f tests for, 279 –280 treatm en t, 280, 280f Multiple epiphyseal dysplasia (MED), 275 –276, 276f Multiple pterygium syndrom e, 260, 260f Multi-variate an alysis, 37, 37f Muscles and tendons, of h and and wrist

extrin sic exten sors, 587 –588 extrin sic flexors, 584 –587 Muscular dystrophy, 256. See also Duch en n e m uscular dystrophy Muscular strain, 182 Musculoskeletal infections, 79 adult infections osteomyelitis, 82 –85 septic arth ritis, 85 –87 antibiotics and m echanism of action, 80 –81, 81t diagnosis of, 81 im aging for detection of bon e scin tigraphy, 82 CT, 81 MRI, 81 –82 PET, 82 radiographs, 81 ultrasoun d, 82 laboratory studies for, 82 n ecrotizin g fasciitis, 93 –95 path ogen esis of, 79 –80 pediatric in fection s osteomyelitis, 87 –89 septic arth ritis, 89 –90 periprosth etic in fection s, 91 –93 Musculoskeletal outcom es in strum ents, 38 Musculoskeletal Tum or Society, 147 Mycophenolate m ofetil, 137 Myelodysplasia (spina bifida), 249 classification , 249 –250 h igh lum bar level ch ildren , 249, 250f low lum bar level (L5) myelodysplasia, 250, 250f m idlum bar myelodysplasia, 249, 250f sacral level in volvem en t, 250 thoracic level patients, 249, 249f h istory an d physical exam in ation , 250 –251 m anagem en t, 251 –252, 251f path ophysiology, 249, 249f presen tation , 250 spin a bifida cystica, 249, 249f spin a bifida occulta, 249, 249f treatm en t of region al deform ities foot an d an kle, 253 h ip, 252 –253, 253f kn ee, 253 spin e, 252, 252f Myelopathy, occurrence of, 467 Myokym ic discharges, 67 Myositis ossifican s, 182 Myotonic discharges, 67 Myxom as, 161 –162

N

Nation al Acute Spin al Cord In jury Study (NASCIS), 438 Nation al Collegiate Ath letic Association , 171, 172f Nation al Coun cil on Radiation Protection an d Measurem en ts (NCRP), 59 Nation al In stitutes of Health , 741 Nation al Spin al Cord In jury Statistical Cen ter, 175

Index Navicular fractures, 777 CT scan in, 777 dorsal lip fractures, 777 navicular body fractures, 777 Neck Ach e, 465. See also Cervical spin e Neck pain , predom in an ce of, 472 –473 Neck Sprain , 465. See also Cervical spine Necrotizin g fasciitis, 93 –94, 233 classification type 1 in fection s, 94 type 2 in fection s, 94 type 3 in fection s, 94 diagn ostic studies, 94 differen tial diagn osis, 94 –95, 651 history an d physical exam ination, 94 path ophysiology of, 650 presen tation , 94, 650 radiograph ic fin din gs/ special studies of, 650 treatm en t, 95, 651 Neer classification , of proxim al h um erus fractures, 523, 524f Neer impin gem en t sign , 537, 538f. See also Sh oulder Neisseria gonorrhoeae, 650 septic arth ritis by, 85 Nerve an atomy, of h an d an d wrist, 594 –595. See also Han d and wrist Nerve con duction study (NCS), 533, 626 Nerve con duction velocity (NCV), 560 Nerve in jury, in h an d an d wrist comparison of sun derlan d an d seddon classification of, 621t differen tial diagn osis, 622 path ophysiology/ classification of, 620 presen tation / physical exam in ation , 620 radiograph ic fin din gs, 622 ten odesis effect, 622 treatm en t of, 622 Nerve in jury, respon ses to, 70 –73 Neural crest cells, 3 Neural tube, 4 closin g of, 5f form ation , 4f Neurapraxic lesion s, 71 Neurofibrom a, 162 Neurom uscular scoliosis, 367 differen tial diagn osis, 370 history an d physical exam ination, 368 –369, 369f path ophysiology an d classification , 367 –368 presen tation , 368 radiograph s, 369, 370f, 371f special tests for, 369 –370 treatm en t n on operative, 370, 371f surgical, 370 –371, 372f Neuropath ic arth ropathy, cause of, 544 Neurotm esis, 71, 72, 72f Neurovascular structures, of elbow, 552 –554, 555f elbow disorders, evaluation of h istory, 554 –556 physical exam in ation , 556 –557 im agin g, 558 neurovascular assessm ent, 557 –558

palpation , 557 physical exam in ation , 557, 557f radiography, 558 ran ge of m otion , 557 stability, 557 Neutroph ils, 120 Nigh tstick fractures, 608 Nodular ten osyn ovitis, causes of, 644 No m an ’s lan d, 616. See also Flexor ten don injuries Non ossifyin g fibrom a, 152, 153f, 154 Non steroidal an ti-in flam m atory drugs (NSAIDs), 139, 527, 629, 687, 704, 741 ch aracteristics of, 140 –142t in hallux rigidus treatm ent, 796 side effects of, 143 for sports in juries, 189 in tarsal tunn el syndrom e treatm ent, 789 Non un ion s, 228 –229 atrophic, 229, 229f and host factors, 230 hypertroph ic n on un ion , 229, 229f infection and, 230 oligotroph ic, 230, 230f Nuclear scin tigraphy, 54 –56, 58 gam m a cam eras, use of, 55 skeletal scin tigraphy (bone scan ), 55 –56 wh ite blood cell scan , 58 Nutrition al rickets, 261. See also Rickets

O

Ober test, in IT ban d syn drom e, 729 Oblique retinacular ligam ent, 588 O’Brien test, in SLAP lesions, 534, 535f. See also Sh oulder Occipitocervical dissociations, 393, 393f Odontoid fractures, 395, 395f, 444 –446 An derson an d D’Alon zo classification of, 445, 445f anterior odontoid screw, 446, 446f incidence of, 444 O’Driscoll classification, of coron oid fractures, 568, 568f Olecranon bursitis differen tial diagn osis of, 580 path ophysiology an d classification of, 580 physical exam in ation in , 580 presen tation of, 580 radiograph ic fin din gs of, 580 special studies in , 580 treatm en t of, 580 –581 Olecranon fossae, 549 Olecran on fractures, 416, 418f. See also Elbow classification , 565 differen tial diagn osis, 567 injury, m ech an ism of, 565 –567 Mayo classification of, 565, 566f patien ts presen tation , 567 physical fin din gs, 567 radiograph ic evaluation , 567 special studies, 567 tension band wiring of, 567f treatm en t, 567

813

Open fractures classification of, 199, 199f type III in jures, 199 type II in jures, 199 type I in jures, 199 defin ition of, 197 diagn osis of, 197 –198 incidence of infection in, 199 as surgical em ergency, 198 –199 tetanus prophylaxis, indications for, 198, 199t treatm en t, 199 –200 Open pelvic fractures, 220 Open reduction and internal fixation (ORIF), 523, 563, 599, 713, 750, 761 Open reduction of hip, 308 –309 Open section defect, 23 Opponens digiti m inim i (ODM), 590 Opponens pollicis (OP), 589 Th e Orth opaedic Traum a Association , 670, 672 Orthopaedic Traum a Association classification , of distal h um erus fractures, 561, 562f Orthopaedic traum a, m anagem ent of acetabular fractures, 220 –224 posterior wall fractures, 224 –225 amputation, traum atic, 225 –227 articular fracture, 214 com partm en t syn drom e, 202 –205, 203f, 204f diagn osis in un con scious patien t an d pediatric population , 203 –204 m anagem ent schem e for patient with, 204f physical exam in ation , 203 pressure m easurem en t, 204 surgical release of fascial com partm en ts, 204 com plication s an d m alun ion s, 228 necrotizin g fasciitis, 233 non un ion s, 228 –230 osteomyelitis, 230 –231 septic arth ritis, 231 –233 diaphyseal fracture, 212 –214 fracture classification system s, 206 –207 fracture-dislocation s, 201, 203f fracture m an agem en t, 207 bon e biology an d physiology, 207 fixation m eth ods, 210, 212 fracture h ealin g, 207, 208f, 209f, 210f preoperative plan n in g, 207, 210, 211f, 212f fractures with n eurovascular com prom ise, 200, 200f open fractures, 197 –200 open pelvic fractures, 220 pelvic rin g in juries, 214 –220 polytraum a patien t, 205 –206 spin al cord in jury, 200 –201, 201f, 202f traum a patien t, evaluation of, 193 blood loss in acute fractures, 194t lower extrem ity, sensory distribution of, 196f physical exam in ation , 193 –196

814

Index

Orthopaedic traum a, m anagem ent of (Contd.) spin al cord in jury, 196 –197 tertiary exam ination, 197 upper extrem ity, sen sory distribution of, 195f vascular in juries with fracture, 197 Ortolani test, 301, 301f Osgood Schlatter syndrom e, 331, 709, 728 Os odon toideum , 381 –382, 382f Ossification groove of Ranvier, 9 Ossification of secon dary cen ters of distal h um erus, 407f Osteitis deform ans. See Paget’s disease of bon e Osteoarthritis (OA), 128 –130, 542, 576, 687 articular cartilage and, 14, 15f diagn osis of, 129 differen tial diagn osis of, 578 of h ip ch aracteristics of, 687 and inflam m atory arthritis, radiograph ic criteria for, 687t prevalen ce of, 687 im aging studies, 129 path ologic m ech an ism s, 129 path ophysiology an d classification of, 577 physical exam in ation in , 578 presen tation of, 577 radiograph ic fin din gs of, 578 risk factor for, 128 special tests in , 578 treatm en t, 129 –130, 578 Osteoarthritis (OA), of kn ee causes of, 737 crystallin e arth ropath ies in , 739 –741 hyaluron ic acid usage in , 741 inflam m atory arthritides, 739 intra-articular corticosteroid injections, usage of, 741 lum bar disc disease in, 738 m en iscectomy, 737 non operative treatm ent of, 741 –742 osteoch on dritis dissecan s, 737 path ophysiology of, 737 –738 patien t evaluation clin ical presen tation of, 738 differen tial diagn osis, 739 –741 im aging of, 738 –739 physical exam in ation of, 738, 738f risk factors of, 736 –737 surgical treatm en t of arthroscopy, 742 kn ee arth rodesis, 744 osteotomy, 742 –743 UKA, 743 –744 total knee arthroplasty complication s of, 746 –747 indications, 744 –745 infection, 747 –748 instability, 749 loosening/ wear, 748 –749 outcom es of, 746 periprosth etic fracture, 749 –751 postoperative pain , 747

postoperative recovery, 746 stiffness/ arthrofibrosis, 749 surgical procedure, 745 –746 th rom boem bolic disease, 747 varus deform ity in , 742 Osteoblast, 16, 18f Osteoblastom a, 149 Osteoblasts, 100 Osteocalcin, 19 Osteochondral autograft tran sport system (OATS), 718 Osteochondral fracture, occurrence of, 717 Osteochondral lesions of talus ch on droplasty in , 773 coron al m agn etic reson an ce im age of, 773f MRI of, 773 path ophysiology an d classification of, 772 –773 physical exam in ation of, 773 posterom edial osteoch on dral lesion , 773f presen tation of, 773 radiographic fin din gs of, 773 special tests for, 773 treatm en t of, 773 –774 Osteochondritis dissecans (O CD), 331 –332, 331f, 332f, 710, 772 classification of, 729 com plication s of, 730 m echanism of injury, 729 patien ts presen tation of, 729 physical exam in ation of, 729 radiographic exam ination of, 730 special tests for, 730 treatm en t of, 730 T2-weigh ted MRI im ages of, 730, 730f Osteochondrom a (Exostosis), 149 –150, 150f Osteochondroses, 346 Osteoclast, 17, 18f Osteocytes, 16 –17 Osteocytic osteolysis, 17 Osteogenesis imperfecta (OI), 265 differen tial diagn osis, 267 path ophysiology, 265 presen tation an d physical exam in ation , 265 –266 radiographs, 266, 266f Sillen ce classification system , 265, 265t special tests for, 266 –267 treatm en t, 267 –268, 267f Osteoid osteom a, 149, 149f and osteoblastom a, 488f (See also Spin e) occurren ce of, 488 Osteomyelitis, 82 in adult population causative organ ism , 82 classification , 82, 83t clin ical presen tation , 83 diagn ostic studies, 83 differen tial diagn osis, 83 history and physical exam in ation , 83 treatm en t, 83 –85, 84f differen tial diagn osis of, 650 path ophysiology of, 650 in pediatric population

causative organ ism , 88 classification , 88 diagn ostic studies, 89 h istory an d physical exam in ation , 88 –89 path ogen esis, 87 –88, 87f presen tation , 88 treatm en t, 89 presen tation / physical exam in ation of, 650 radiographic findings/ special studies of, 649 in traum a patients, 230 –231 anatom ic classification system for, 231, 231f im aging m odalities for, 231 treatm en t for, 231, 232f treatm en t of, 650 Osteonecrosis, 695 –696 defin ition of, 695 inciden ce of, 695 treatm en t for, 696 Osteopetrosis, 268 classification , 268 presen tation an d physical exam in ation , 268 radiographs, 268, 269f, 270f tests for, 268 treatm en t, 268 Osteoporosis, 102 classification , 102 –103 h igh -turn over osteoporosis, 103 low-turnover osteoporosis, 103 prim ary, 102 –103 secon dary, 103, 103t, 105t DEXA screen in g for, 58 diagn osis, 103 –104 epidem iology, 102 evaluation for, 104 laboratory investigations, 104 n onph arm acologic treatm en t, 105 ph arm acologic treatm en t, 105 –106 bisph osph on ates, 106 –107, 107t calciton in , 106 estrogen , 106 selective estrogen receptor m odulators (SERMs), 106 teriparatide, 107 risk of falls and fracture risk, assessm ent of, 104 –105 Osteosarcom a, 156, 157f, 489. See also Spin e subtypes of, 157t Ottawa Ankle Rules, 766

P

Paget’s disease of bon e, 112 clin ical presen tation , 113 –114 diagn ostic evaluation , 114, 114f epidem iology and etiology, 112 –113 path ology, 113 treatm en t, 114 Pain scale, 30 Paired t test, 30 Palm ar forearm an d h an d, blood supply to, 593f Palm aris brevis (PB), 590

Index Palm aris lon gus (PL), 584 Pan n us, 782. See also Rheum atoid foot Paraten on , 587. See also Muscles and ten dons, of hand and wrist Parathyroid h orm on e (PTH), 98, 261 Paraxial m esoderm , 4 Park–Harris growth lines, 400, 401f Paronych ia ch ron ic, surgical m an agem en t of, 647, 647f differen tial diagn osis of, 647 path ophysiology of, 647 presen tation / physical exam in ation of, 647 radiograph ic fin din gs of, 647 treatm en t of, 647 Passivation layer, 27 Patella dislocation classification of, 716 differen tial diagn osis of, 717 m echan ism of injury, 716 –717 patien ts presen tation of, 717 physical exam in ation of, 717 radiograph ic exam in ation of, 717 relevant anatomy of, 717 special tests for, 717 treatm en t of, 717 Patella fractures classification of, 713, 713f complication of, 714 differen tial diagn osis of, 714 m echan ism of injury, 714 patien ts presen tation of, 714 physical exam in ation of, 714 radiograph ic exam in ation of, 714 relevant anatomy of, 714 special tests for, 714 treatm en t of, 714, 714f Patella glide test, role of, 709 Patellar ten don itis, 728 Patellar tilt sign , 728 Patellar tilt test, for patellofem oral join t assessm en t, 709, 709f Patella ten don ruptures, 715 classification of, 716 complication of, 716 differen tial diagn osis of, 716 m echan ism of injury, 716 patien ts presen tation of, 716 physical exam in ation of, 716 radiograph ic exam ination of, 716, 716f relevant anatomy of, 716 special tests for, 716 treatm en t of, 716 Patellofem oral join t, 14 Patellofem oral join t assessm en t, 708 –709, 708f patella glide test for, 709 patellar tilt test for, 709, 709f Patellofem oral pain syn drom e, 708 classification of, 727 complication s of, 729 differen tial diagn osis of, 728 Fulkerson procedure in, 729 m echan ism of injury, 727 patien ts presen tation of, 727 physical exam in ation of, 727 –728

Q angle, 727, 727f radiograph ic exam in ation of, 728, 728f relevant an atomy of, 727 special tests for, 728 surgical treatm en t of, 728 treatm en t of, 728 –729 Pauwels’classification , of fem oral n eck fractures, 672, 674f, 675f Pavlik h arn ess, 306 –307, 306f Pearson ’s ch i-square test, 30 Pearson ’s r, 36 Pediatric m usculoskeletal traum a ch ild abuse an d, 433 –434 ch ild skeleton , ch aracteristics of, 399 –401, 400f, 401f, 402f elbow injuries, 405, 407, 407f fractures of distal h um eral physis, 415 –416 lateral condyle fractures, 412 –414 m edial epicondyle fractures, 414 –415 olecran on fractures, 416 radial n eck fractures, 416 –418 supracon dylar fractures, 407 –412 T-con dylar fractures, 416 forearm an d wrist in juries diaphyseal fractures, 420 distal radius fractures, 420, 422 hand injuries, 422 Monteggia fracture–dislocation s, 418 –420 hip and th igh fractures diaphyseal fem ur fractures, 424 –427 hip fractures, 423 –424 kn ee fractures distal fem oral physeal fractures, 427 proxim al tibial fractures, 429 tibial em in en ce fractures, 427 –428 tibial tubercle avulsion s, 428 –429 leg an d ankle injuries ankle fractures, 431 –433 foot fractures, 433 tibial diaphyseal fractures, 429 –431 pediatric polytraum a, 401 –404 pelvic fractures, 422 –423 shoulder and arm in juries clavicle fractures an d dislocation s, 404 hum eral sh aft fractures, 405, 407f proxim al h um erus fractures, 404 –405, 406f treatm en t for ch ildren ’s fractures, 401 Pediatric pelvic fractures, 422 –423 Pediatric polytraum a, 401, 403, 403t, 404t Pediatric spin e, 358 back pain , 387 –391 cervical spin e disorders atlan toaxial rotatory displacem ent, 382 con gen ital m uscular torticollis, 382 –383 Down syn drom e, 383 –384 Klippel–Feil syn drom e, 380 –381 os odon toideum , 381 –382 con gen ital spin al an om alies, 371 –377 idiopathic scoliosis, 358 –367 neurom uscular scoliosis, 367 –371 Sch euerm an n kyph osis, 377 –380

815

specific in juries atlantoaxial injuries, 395 atlas fractures, 393, 394f, 395 Hangm an fractures, 395 occipitocervical in juries, 393 odon toid fractures, 395 SCIWORA, 398 subaxial cervical spin e in juries, 395 –397 th oracolum bar fractures, 397 –398 spin e traum a, 391 –393 spon dylolysis an d spon dylolisth esis, 384 –387 Pediatric Traum a Score, 401, 404t Pelvic rin g in juries, 214 –216 bleedin g, m an agem en t of, 217 –218 classification system s for, 218, 219f com plication s related to, 219 –220 m anagem ent of, based on varying h em odyn am ics, 216f, 217 and m obilization, 218 –219 open in juries, 220 radiograph ic assessm en t, 218 Pem berton osteotomy, 308 Pen icillin s, 80 Periarticular fractures, 201 Perich on dral vessels, 9 Perich on drial rin g of La Croix, 9 Periorbital con tusion , 175 Periosteum , in ch ild, 399 Periph eral myelin protein (PMP) gene, 254 Periph eral n erve repair, tech n iques of, 624f Periprosth etic in fection , 91 classification , 91 diagn ostic studies, 91 –92, 92f differen tial diagn osis, 92 h istory an d physical exam in ation , 91 incidence, 91 presentation , 91 spread of, 91 treatm en t, 92 –93 Peron eal artery, 759 Peron eal n erve, 195 –196 Peron eal ten don path ology exam in ation of, 789 path ophysiology an d classification of, 789 presen tation of, 789 radiograph s of, 789 –790 treatm en t of, 790 Peron eus lon gus, 758 Ph alan geal dislocation s classification of, 597 m echanism of in jury, 597 presen tation an d physical exam in ation , 597 radiograph ic fin din gs, 597 treatm en t of, 597 –598, 598f Ph alan geal fractures, 782 Ph alen test, in CTS, 626 Ph ocom elia, 651 Physeal fractures, 399 –401 Salter–Harris classification of, 400f Pigm en ted villon odular syn ovitis ( PVNS), 162

816

Index

Pilon fractures classification of, 761, 762f im aging of, 762 –763 m echanism of in jury, 761 physical exam in ation of, 762 presen tation of, 761 rotational and axially loadin g fractures, ch aracteristics of, 762t treatm en t of, 763 Pipkin ’s classification , of fem oral h ead fractures, 670, 670f Piriform is m uscle, role of, 655 Pisiform fractures. See also Han d an d wrist classification of, 606 m echanism of in jury, 606 presen tation an d physical exam in ation , 606 radiograph ic fin din gs, 606 treatm en t of, 606 Pivot sh ift test, for ACL, 706 Plan ovalgus, 246, 247f Plan tar fasciitis differen tial diagn osis of, 793 exam ination of, 793 heel pain , 792 nigh t splin tin g in , 793 path ophysiology of, 792 presen tation of, 792 radiograph s of, 793 treatm en t of, 793 Plasm a cell tum or, 158 Plexopathy, diagn osis of, 76 Pn eum atic an tish ock garm en ts, 217 –218 Pn eum oth orax, 180 Poisson ’s ratio, 23 Polar m om en t of in ertia, 23, 23f Polydactyly, 349 –350, 351f. See Preaxial duplication Polym erase ch ain reaction (PCR), 82 Polym ethyl m eth acrylate (PMM), 26 Polym ethylm eth acrylate (PMMA), 84 Polymyalgia rh eum atica (PMR), 137 Polyn europathy, diagn osis of, 74 –75 Polytraum a patien t, 205 m anagem ent of dam age con trol orth opaedics, 205, 205f early total care, 205 Popliteal cysts, 332 Positive sh arp waves, 67, 67f Positron em ission tom ography (PET) im aging, 58 Postcon cussive syn drom e, 171 Posterior atlan toden tal in terval (pADI), 469 Posterior cord syn drom e, 436. See also Spin al cord in jury (SCI) Posterior cruciate ligam en t (PCL), 699, 745 godfrey test for, 707 posterior drawer test, 708f quadriceps active test for, 707 sprain classification of, 723 complication s of, 724

differen tial diagn osis of, 724 m echanism of injury, 723 patien ts presen tation of, 723 physical exam in ation of, 723 radiographic exam ination of, 724 relevan t anatomy of, 723 special tests for, 724 treatm en t of, 724 two bun dles of, 700f Posterior in ferior glen oh um eral ligam en t (PIGHL), 503 Posterior in ferior tibiofibular (PITFL), 756f Posterior in terosseous n erve (PIN), 410, 554 Posterior in terosseous syn drom e differen tial diagn osis of, 631 path ophysiology of, 631 presen tation / physical exam in ation of, 631 special studies in , 631 treatm en t of, 631 Posterior lon gitudin al ligam en t (PLL), 438 Posterior rotator cuff m uscles, evaluation of, 516, 517f. See also Sh oulder Posterior superior iliac spin e (PSIS), 653 Posterior talofibular ligam en t (PTFL), 754, 756f Posterolateral rotatory in stability (PLRI), 551 Postm en opausal osteoporosis, 102 Postreduction radiograph s, role of, 570 Posttraum atic arth ritis differen tial diagn osis of, 579 path ophysiology an d classification of, 577 physical exam in ation in , 578 presen tation of, 577 radiographic fin din gs of, 578 special tests in , 579 treatm en t of, 579 Pott’s paraplegia, 493 Power an alysis, 36 Preaxial duplication , 652 Pregabalin , 130 Prim ary ossification cen ter, 3 Prim itive streak, 3 Prin ceps pollicis, fun ction of, 593 Prolon ged QT syn drom e, 183 Pron ator syn drom e differen tial diagn osis of, 626 path ophysiology of, 626 physical exam in ation of, 626 presen tation of, 626 special studies in , 626 treatm en t of, 629 Pron ator teres (PT), 552 Protein ases, 13 Proteus mirabilis, 786 Proxim al an d m iddle ph alan geal fractures classification of, 597, 598f m echanism of injury, 597 presen tation an d physical exam in ation , 597 radiographic fin din gs, 597 treatm en t of, 597

Proxim al fem oral focal deficien cy (PFFD), 284 classification Aitken classification , 285, 285f Gillespie classification, 285 differen tial diagn osis, 286 path ophysiology, 284 –285 presen tation an d physical exam in ation , 285 –286, 286f radiographs, 286, 286f treatm en t, 286 –288 Proxim al h um erus, 503f blood supply of, 502, 503f fracture, 502 fractures, in sh oulder classification of, 523 differen tial diagn osis, 525 m echanism of injury, 523 patien ts presen tation , 523 physical exam in ation , 523 –524 radiographic evaluation, 524 special tests, 524 –525 treatm en t of, 525, 525f Proxim al h um erus fractures, 404 –405, 406f Proxim al in terph alan geal (PIP) join ts, 585, 633 –634, 757 Proxim al radiouln ar join ts, fun ction of, 549 Proxim al row carpectomy (PRC), 604 Proxim al tibial physeal fractures, 429, 430f Proxim al tibiofibular join t, of kn ee, 700 Proxim al uln a, 549 Pseudogout, causes of, 741, 741f Pseudohypertrophy, 257 Pseudolockin g, defin ition of, 704. See also Kn ee an d leg in juries Pseudomonas aeruginosa, 786 Pseudosubluxation , 392, 392f 31P solid-state NMR im aging, 101 Psoriatic arth ritis, 133 differen tial diagn osis of, 639 path ophysiology of, 639 presen tation / physical exam in ation of, 639 radiographic findings of, 639 treatm en t of, 639 Pulm onary contusion, 180, 180f Pulm on ary em boli (PE), 694, 747 Pulvin ar, 300 P values, 35 Pyogen ic flexor ten osyn ovitis differen tial diagn osis of, 649 path ophysiology of, 648 presen tation / physical exam in ation of, 649 treatm en t of, 649

Q

Q tests, 35 Quadriceps active test, for PCL, 707 Quadriceps strain s, 715 Quadriceps tendon rupture, 714 classification of, 715 complication of, 715 differen tial diagn osis of, 715 m echanism of injury, 715

Index patien ts presen tation of, 715 physical exam in ation of, 715 relevan t anatomy of, 715 special tests for, 715 treatm en t of, 715, 715f Quadriplegia, 241

R

Radial clubhand, 289 –291, 290f Radial head fractures. See also Elbow classification , 563, 565f differen tial diagn osis, 565 in jury, m ech an ism of, 563 patien ts presen tation , 563 physical fin din gs, 564 –565 radiograph ic evaluation , 565 radiograph s of open reduction an d in tern al fixation of, 566f special studies, 565 treatm en t of, 565 Radial neck fractures, 416 –418, 418f Radial nerve, 194, 594 –595 Radial shaft fractures. See also Hand and wrist classification of, 608 m echan ism of injury, 608 presen tation an d physical exam in ation , 608 radiograph ic fin din gs, 608 treatm en t of, 608 Radial tunnel syndrom e differen tial diagn osis of, 631 path ophysiology of, 631 physical exam in ation of, 631 presen tation of, 631 radial n erve compression in , 632f special studies in , 631 treatm en t of, 631 Radiation exposure, to orthopaedic surgeon , 58 –59 Radiculopathies, diagnosis of, 75 electrodiagnostic testing, pitfalls in , 75 –76 m otor NCS in , 75 needle EMG for, 75 sen sory NCS in , 75 Radiocapitellar, function of, 549 Radiocapitellar joint, 579 Radiocarpal instability, 610 Radiocarpal joint, 583 Radiographic exam in ation, of sh oulder, 518 –519. See also Sh oulder Radiography, plain, 39 cervical spin e lateral view, 39, 40 oblique views, 40 pillar view, 40 swim m er’s view, 39 –40 foot an d an kle Broden view, 44 Canale and Kelly view, 44, 46f Cobey view, 44 –45 Harris-Beath view, 44 m ortise view, 43 –44 stan dard projections of foot, 44 han d an d wrist, 41 carpal tun n el view, 42

clen ch ed fist view, 42 lateral view, 41 –42 kn ee AP view, 43, 45f Merchant view, 43 patellofem oral view, 43 sunrise view, 43 tun n el view, 43 pelvis an d h ip Ferguson view, 43 frog leg lateral view, 43 groin lateral view, 43 iliac oblique x-ray, 42 –43, 43f inlet view, 43 Judet views, 42, 42f outlet view, 43, 44f standard AP view, 42 shoulder anteroposterior (AP) of, 40 –41, 40f axillary view, 41 scapular Y view, 41, 41f serendipity view, 41 Stryker/ n otch view, 41, 41f West Poin t view, 41 Zan ca (apical oblique) view, 41, 42f Random ized clin ical trials (RCTs), 35 Range-of-m otion exercises, 188, 188f Ran ge of m otion (ROM), 501, 503, 514, 544 evaluation of, 515 Reactive arthritis, 132 –133 Receiver operator curve, 37, 37f Reconstructive osteotom ies, 309 –310 Rectus fem oris m uscle, 700 Referred pain, definition of, 473. See also Lum bar spine Reflex sympathetic dystrophy (RSD), 641 Regan and Morrey classification , of coron oid fractures, 568, 568f Regression coefficien t, 36 Reim er m igration percentage, 243, 244f Rem , 59 Ren al con tusion , 181 Renal osteodystrophy, 110, 263, 263f clin ical presen tation , 111 path ophysiology of, 110 –111, 111f radiograph ic features, 111 –112, 111f, 112f rugger jersey spin e, 113f treatm en t, 112 Repetitive nerve stim ulation (RNS) studies, 61, 64, 64f decrem en t, 64 facilitation , 64 postexercise exh austion , 64, 65f Replantation classification of, 622 m echanism of injury, 622 physical exam in ation , 622 radiograph ic fin din gs, 622 treatm en t of, 622 –625 Rest, ice, compression, elevation, (RICE), 768 Reverse shoulder arth roplasty, in cuff tear arthropathy treatm ent, 546, 546f Rheum atic disorders, 125 crystal-in duced arth ropath ies, 133 –135

817

fibromyalgia, 130 infectious arthritis, 137 –138 osteoarth ritis, 128 –130 ph arm acologic th erapy for, 138 –139 analgesics, 139 corticosteroids, 143 NSAIDs, 139 –143 SAARDs an d cytotoxic drugs, 144, 144t polymyalgia rh eum atica, 137 rh eum atoid arth ritis, 125 –128 seron egative spon dyloarth ropath ies, 130 –133 system ic lupus eryth em atosus, 135 –137 Rheum atoid arthritis (RA), 125 –128, 468 –470, 469f atlantoaxial instability, 469 classification of, 126, 127t in elbow, 543, 549 differen tial diagn osis of, 576 –577 Mayo classification of, 576 path ophysiology an d classification of, 576 physical exam in ation in , 576 presentation of, 576 radiograph ic fin din gs of, 576 special tests in, 576 treatm en t of, 577 extraarticular m an ifestation s of, 128 h allm ark of, 126 in hand and wrist classification of, 638 differen tial diagn osis of, 639 Mannerfelt lesion, 638 path ophysiology of, 638 presen tation / physical exam in ation of, 638 –639 radiograph ic fin din gs/ special studies of, 639 treatm en t of, 639 Vaugh n –Jackson lesion, 638 h an d in volvem en t in , 127 –128 join ts in volved in , 126, 127f laboratory and radiographic testing, 126 –127 treatm en t, 128 treatm en t of, 470 Rheum atoid factor (RF), 119, 120 Rheum atoid foot appearance of, 783f h in dfoot surgery in , 784 path ophysiology an d classification of, 782 –783 physical exam in ation of, 783 presen tation of, 783 radiograph ic fin din gs of, 783 treatm en t of, 784 weigh t-bearin g radiograph s for, 783 Rib fractures, 179 Rib vertebral angle difference (RVAD), m easurem en t of, 362, 364f Riche –Cann ieu anom aly, 66 Rickets, 261 classification , 261 diagn ostic tests, 263 differen tial diagn osis, 263 –264 etiology of, 263, 263t

818

Index

Rickets (Contd.) and osteom alacia bioch em ical ch an ges in , 109t causes of, 108t clin ical presen tation , 108 –109 defin ition s of, 107 –108 etiology of, 108 laboratory investigation s, 109 prevalen ce, 108 radiograph ic features, 109 –110 treatm en t, 110 path ophysiology, 261 calcium m etabolism , 261, 262f presen tation an d physical exam in ation , 261 –263 radiograph ic fin din gs in , 263, 264f treatm en t, 264 –265 Rifampin , 80, 81t Risser sign, 364f Rituxim ab, 128 Rockwood classification, of injuries to AC joints, 526, 526f. See also Sh oulder Rolando fracture, 600, 600f Rotator cuff disease, 543 Rotator cuff m uscles, 508 –509 defin ition of, 508 role of, 508 Rotator cuff pathology, of shoulder pain. See also Sh oulder differen tial diagn osis, 538 –539 Hawkins im pin gem ent sign, 537, 538f Neer impin gem en t sign , 537, 538f path ophysiology an d classification , 536 –537 patien ts presen tation , 537 physical exam in ation , 537 radiograph ic fin din gs, 537 special tests, 537 –538 th eories in , 536 treatm en t of, 539 –540 Rotator interval, definition of, 509 Rugger jersey appearan ce, of spin e, 268, 270f Run ner’s knee, 701, 729 Russell–Taylor’s classification, of subtroch an teric fem ur fractures, 681, 683f

S

Salter Harris type I fractures, 522 Salter osteotomy, 308, 310, 310f Salvage osteotom ies, 310 –311 San ders’classification , of calcan eal fractures, 46, 48f, 774, 775f Saph en ous n erve, 759 Scaph ocapitate (SC), 612 Scaph ocapitate syn drom e, 605 Scaph oid fractures. See also Han d and wrist classification of, 601, 602f m agnetic resonance im aging of, 603f m echanism of injury, 601 presen tation an d physical exam in ation , 601 radiographic findings, 601, 602f special studies, 602 –603, 602f treatm en t of, 603 –604, 603f

Scaph oid sh ift test, 611, 611f Scaph olun ate advan ced collapse (SLAC)/ Scaphoid nonunion advance collapse (SNAC) wrist classification of, 636 differen tial diagn osis of, 637 path ophysiology of, 636 physical exam in ation of, 637 presen tation of, 637 radiographic findings of, 637 treatm en t of, 637 –638 Scaph o-trapezial-trapezoidal (STT) join t, 612, 636 Scapula anterior and posterior view of, 504f m uscular attachm en ts to, 504t role of, 502 Scapular m overs, 511 –512, 512f Scapuloth oracic articulation , 501, 502f, 505 –507 Scapuloth oracic bursa, location of, 507f Sch atzker classification , of tibial plateau fractures, 712, 712f Sch euerm an n kyph osis, 377 differen tial diagn osis, 378 –379 MRI for, 378 n orm al sagittal align m en t of spin e, 378f path ophysiology, 377 physical exam in ation , 377 –378, 378f, 379f presen tation , 377 radiographs, 378 treatm en t n on operative, 379 surgical, 379 –380, 380f Sch wan n om as, 162 Sciatic n erve, 196, 220 injuries, in hip dislocations, 667 role of, 657 Scoliosis, 484. See also Adult scoliosis Scurvy, 268, 270 Secon dary adh esive capsulitis, defin ition of, 546. See also Adh esive capsulitis Secon dary impin gem en t syn drom e, 547 Secon d-impact syn drom e, 171, 173 Seddon classification , for periph eral injuries, 70 axonotm esis, 71 n eurapraxia, 70 –71 n eurotm esis, 71 Sein sh eim er’s classification , of subtrochan teric fem ur fractures, 681, 682f Selection bias, 31 analysis phase, con trol in m ultivariate analysis, 31 simple adjustm en t, 31 stratification, 31 design ph ase, con trol in m atching, 31 ran dom ization, 31 restriction , 31 Selective dorsal rh izotomy, 244 Selective Estrogen Receptor Modulators (SERMs), 106

Sem m es–Wein stein testin g in compressive n europath ies, 626 in diabetic foot, 785 Sen ile osteoporosis, 102 Sen sory n erve action poten tial (SNAP), 62, 62f Septic arth ritis in adult population , 85 causative path ogen , 85 classification , 85 clin ical presen tation , 85 diagn ostic studies, 86 history an d physical exam in ation , 85 –86 treatm en t, 86 –87 in ch ildren classification , 90 clin ical presen tation , 90 diagn ostic studies, 90 differen tial diagn osis, 90 history an d physical exam in ation , 90 path ogen esis, 89 treatm en t, 90 differen tial diagn osis of, 650 path ophysiology of, 649 presen tation / physical exam in ation of, 649 radiograph ic fin din gs/ special studies of, 649 in traum a patien ts, 231 –233 treatm en t of, 650 Sequestra, 650. See also Osteomyelitis Seron egative spon dyloarth ropath ies, 130 an kylosin g spon dylitis, 130 –132 enteropathic arthritis, 133 psoriatic arth ritis, 133 reactive arthritis, 132 –133 Serratus anterior m uscle, role of, 511 Sesam oid fractures, 782 Sever disease, 346 Seym our fractures, 596 Sh in splin ts. See Medial tibial stress syn drom e Sh oulder anterior capsular structures of a left, 505f articulation s of, 502f atraum atic con dition s acrom ioclavicular join t arth ritis, 541 –542 adh esive capsulitis, 546 –547 calcific ten don itis, 540 –541 glen oh um eral arth ritis, 542 –546 rotator cuff path ology, 536 –540 complex, 501 external rotation assessm ent of, 515f forward elevation assessm en t of, 515f fun ction al an atomy acrom ioclavicular join t, 504 glen oh um eral join t, 503 –504 glen oh um eral m overs, 509 –511 neurovascular structures, 512 osteology, 501 –503 rotator cuff m uscles, 508 –509 scapular m overs, 511 –512 scapuloth oracic articulation , 505 –507 stern oclavicular join t, 504 –505 subacrom ial space, 507

Index fun ction of, 501 inspection of, 514 instability classification, 528t internal rotation assessm ent of, 515f n eurovascular assessm ent of, 517 –518 pain , source of, 507 palpation of, 514 problem s, evaluation of h istory, 512 –514 m ultiple im agin g m odalities, 518 –520 physical exam in ation , 514 –518 ran ge of m otion in , 514 –516 stren gth testin g of, 516 –517 tests for exam in ation of, 514t traum atic in juries to acrom ioclavicular joint sprains, 525 –528 clavicle fractures, 520 –523 glen oh um eral in stability, 528 –533 proxim al h um erus fractures, 523 –525 SLAP lesion s, 533 –536 zan ca view of, 518, 521, 522f, 527 Shoulder separation , 525 Simple bon e cyst, 152, 153f Sin gle-even t m ultilevel surgery (SEMLS), 244 Sin gle-fiber EMG (SFEMG), 69 –70 fiber den sity, an alysis of, 69 jitter, an alysis of, 69 –70 myasth en ia gravis (MG), diagnosis of, 70 Skier’s th um b, 601 Skin an d n ail traum a Atasoy–Klein ert V-Y advan cem en t flap, 613f classification of, 612, 613f cross-fin ger flap, usage of, 613, 615f Moberg advan cem ent flap, 613, 614f presen tation an d physical exam in ation , 612 radiograph ic fin din gs, 612 –613 th en ar flap in , 613, 615f treatm en t of, 613 Slidin g screw plate device, in intertrochanteric h ip fractures, 679, 679f Slipped capital fem oral epiphysis (SCFE), 263, 263f, 312, 312f classification , 312 –313 com plication s, 316, 320f avascular n ecrosis (AVN) of fem oral h ead, 318, 321f joint space n arrowing with ch on drolysis, 316, 318, 320f im aging studies, 315, 315f, 316f path ophysiology, 312 physical exam in ation , 313 –314, 314f presen tation , 313, 313f radiograph s, 314 –315, 314f, 315f treatm en t, 316, 317f, 318f, 319f Slow-actin g an tirh eum atic drug (SAARD), 132, 144, 144t Sm all-fiber polyn europathy, 75 Sm ith –Peterson ’s approach , in THA, 688, 689f

Soft-tissue tum ors clin ical presen tation s, 158 differen tial diagn osis, 159 radiographic evaluation, 158 –159 Som ites, 4 Space available for th e cord (SAC), 441 Spastic CP, 241 Spear tackler’s spin e, 177, 177f SPECT (sin gle ph oton em ission com puted tom ography) im aging, 55 Spin al cord in jury (SCI), 435 –438 anterior cord syn drom e in, 436 Brown -Sequard syn drom e in , 436 bulbocavern osus reflex in , 435 –436 cauda equin a syn drom e in , 436 cen tral cord syn drom e in , 436 decom pression , role of, 437 evaluation of, 436 –437 Fran kel gradin g system , 436 Gardn er-Wells ton gs, usage of, 437 h alo brace im m obilization , 437 inciden ce of, 435 m anagem ent of, 437 –438 m ethylprednisolon e usage in, 438 MRI of, 437 posterior cord syn drom e in , 436 radiographic assessm ent of, 437 treatm en t, Guttm an n ’s guidelin es, 438 Spin al cord in jury with out radiograph ic abn orm ality (SCIWORA), 391, 398 Spin al stability, 438 –439 defin ition of, 438 th ree-colum n th eory, 439f Spinal sten osis, 476 –477, 478f defin ition of, 476 form of, 476 occurren ce of, 477 Spin e degen erative disorders of, 460 infections epidural abscess, 496 –497 gallium scanning, 494 indium -111-labeled leukocyte scan n in g, 494 MRI in, 494, 495f pyogenic in fection, 493 –496 tech netium -99 m bon e scan, 494 treatm en t of, 495 tuberculosis of, 497 –498 traum a SCI, 435 –438 tum ors of, 486 –488 aneurysm bone cyst, 488 giant cell tum or, 489 h em an giom a, 488 –489 osteoid osteom a an d osteoblastom a, 488 prim ary ben ign tum ors, 488 prim ary m align an t n eoplasm s, 489 –493 Spine fractures, pediatric, 391 m echanism s of injury, 391 physical exam in ation , 391 radiographs, 391 –392 special tests for, 391 –392

819

treatm en t, 392 –393, 393f un ique factors in, 391 Spin olam in ar lin e (Swisch uk’s lin e), align m en t of, 392, 392f Splen ic injury, 181 Spon dyloepiphyseal dysplasia (SED), 276, 277f Spon dylolisth esis, 179, 477 –480 causes of, 477 defin ition of, 477 degen erative, 479 Spon dylolysis, 179, 179f Spon dylolysis an d spon dylolisth esis, 384 differen tial diagn osis, 386 path ophysiology an d classification , 384, 384f physical exam in ation , 385 presen tation , 384 radiograph ic fin din gs, 385 Meyerdin g classification , 385, 385f Scotty dog, 385f slip an gle, m easurem en t of, 385, 385f special tests for, 386 treatm en t, 386, 387f Spon dylosis, 460. See also Spin e Sports m edicine, 165 abdom in al in jury, 180 –181, 180f h epatic injury, 181 pancreatic injury, 181 renal contusion, 181 splenic injury, 181 ath letic n utrition , 190 –191 com m on ath letic in juries, 170 –171 ethics in, 166 facial in jury, 174 –175 cauliflower ear, 175, 175f den tal in jury, 175 eye in juries, 174 –175, 175f facial laceration s, 174 n asal fractures, 174 vascularity of nasal cavity, 174f fem ale athlete, care of, 187 –188 gam e coverage face m ask rem oval tool, 171f in jured ath lete, approach to, 170 logroll tech n ique, in spin e in jury, 170f m edical bag, con tents of, 169t on -field em ergen cies, poten tial causes of, 169t on -site m edical supplies, 169t preparedn ess, 169 h ead in juries, sports-related, 171 con cussion , 171, 172f, 173 in tracran ial h em orrh age, 173 –174, 174f m edical conditions, effecting athletes asth m a/ exercise-in duced bronchospasm , 184 –185 cardiovascular disease, 183 –184 environm ental illness, 185 –187 in fectious disease, 185 m usculoskeletal injury, 181 compartm ent syndrom e, 181 –182 ligam en tous in jury, 182 m uscular injury, 182

820

Index

Sports m edicin e (Contd.) orth opaedic em ergencies, 181 stress fractures, 182 –183, 183f ph arm acology of sports anti-inflam m atories and analgesics, 189 supplem en ts, vitam ins, and drugs, 189 –190 preparticipation evaluation , 166 –167 classification of sports by con tact, 168t clearan ce to play, 167 h ealth question n aire, 167 m usculoskeletal screening exam in ation , 168t physical exam in ation , 167 rehabilitation , prin ciples of, 188 –189 spin al cord in juries, 175 cervical spin e, 175, 177 guidelin es for ath letes with cervical spin e abn orm alities, 178t instability, 176f, 177 lateral cervical spine radiograph, 176f n eck in juries, 177 –178 Spear tackler’s spin e, 177, 177f stin gers an d tran sient quadriplegia, 178 –179 th oracolum bar spin e, 179 team physician, role of, 165 –166 ability, 166 affability, 166 availability, 166 th oracic in jury, 179 –180 com m otio cordis, 179 pn eum oth orax, 180 pulm on ary con tusion , 180, 180f rib fractures, 179 tension pneum othorax, 180 Spren gel deform ity, 346 –347, 347f Spurlin g’s sign , 461. See also Cervical radiculopathy Stah eli sh elf procedure, 311, 312f Staphylococcus aureus, 493, 646, 647, 650, 747, 786 m usculoskeletal infection s by, 80 Staphylococcus epidermidis, 493, 747, 786 Staphylococcus in fection , in ath letes, 185 Static tech n ique, ultrason ograph ic m eth od in DDH, 304 Statistical tests, 36, 36f Stein berg sign , 282, 283f Sten er lesion , in gam ekeeper’s th um b, 601, 601f Sten osin g ten osyn ovitis. See Trigger fin ger Stern oclavicular (SC) join t, 501, 502f, 504 –505 stabilization of, 506f Steroid h orm on es, 10 Stickler syn drom e, 284 Still disease. See Juvenile rheum atoid arthritis (JRA) Stin ger/ burn er, 178 –179, 178f Straigh t leg raisin g test (SLRT), 388, 390, 473, 474

Strain defin ition of, 22 norm al strain, 22 shear strain, 22 Streptococcus, 646 Stress, 21 –22 defin ition of, 21 –22 norm al stress, 22 shear stress, 22 Stress con cen tration effect, 23 Stress fractures, 182 –183, 183f Stress radiograph s, usage of, 542 Stress–strain curve, 22, 22f elastic region , 22 m odulus of elasticity, 22 –23 plastic region , 22 ultim ate ten sile stren gth (UTS), 22 yield point, 22 Stron g capsular ligam en t (SC ligam en t), 505 Struth ers, arcade of, 630f Studen t’s t test, 30, 36 Study design analytic observational studies, 33 case-con trol studies, 33 –34 case series, 33, 34 case studies, 33 coh ort studies, 34 cross-section al studies, 33, 34 descriptive observation al studies, 33 experim ental study, 34 m eta-analysis, 34 prospective coh orts, 35 prospective studies, 34, 34f random ized clinical trial, 34, 35 retrospective studies, 34 reviews, 35 Subacrom ial bursa, role of, 507 Subacrom ial space, 501, 502f, 507 Subaxial cervical spin e in juries, 395 burst fractures, 395, 397 com pression fractures, 395 facet dislocation s, 395 ligam entous disruptions, 395, 396f Subaxial cervical spin e traum a, 448. See also Upper cervical spin e traum a classification of, 448 Subdural h em atom a, 173 –174, 174f Subluxation , defin ition of, 528. See also Glen oh um eral (GH) join t Subscapularis m uscle, role of, 509 Subtalar join t, an atomy of, 756 Subtroch an teric fem ur fractures, 680 –681 classification of, 681 deform in g forces on , 681f differen tial diagn osis of, 682 Fieldin g’s classification of, 681 m echanism of in jury, 681 patients presen tation of, 681 physical exam in ation of, 681 radiograph ic exam in ation of, 681 –682 Russell–Taylor’s classification of, 681, 683f Sein sheim er’s classification of, 681, 682f special tests for, 682 treatm en t of, 682 –683, 684f

Sulfasalazin e, 132 Superior glen oh um eral ligam en t (SGHL), 503 Superior labrum an terior to posterior (SLAP) lesions, in shoulder bucket-h an dle tear, 533 classification of, 533, 534f differen tial diagn osis for, 535 Mayo sheer test, 535 m echanism of injury, 533 MRI of, 535, 535f O’Brien test, 534, 535f patien ts presen tation , 534 physical exam in ation , 534 –535 radiographic findings, 535 special studies, 535 treatm en t, 535 –536 Superior labrum an terior to posterior (SLAP) tears, 519 Supination-external rotation (SER), 763 Supracon dylar h um erus fractures, 407 complication s of, 410 deform ity resultin g from , 412, 412f exten sion -type, 407, 408f flexion -type, 407, 408f Gartland classification, 407 –408, 409f hyperexten sion loadin g an d, 407 inciden ce of, 407 m echanically vulnerable area, 407, 408f and physical an d neurologic exam in ation , 410 radiographic m easurem ents for, 408, 409f, 410 treatm en t of, 410 vascular in juries associated with , 410, 412f volkm ann ischem ic contracture by, 411 –412, 412f Supraspin atus cuff m uscle, role of, 508 Supraspin atus dysfunction, 516 Surgical n eck, 501 Syn dactyly, 346, 349, 350f Syn ovial ch on drom atosis, 162 Syn ovial fluid, 501 Syn ovial fluid an alysis, 86 Syn ovial sarcom a, 163, 163f System atic reviews, 35 System ic lupus eryth em atosus (SLE), 135 –137, 136t ACR diagn ostic criteria for, 137t clin ical symptom s, 136t

T

Talus fractures Can ale an d Kelly view for, 772f classification of, 770 differen tial diagn osis of, 771 –772 Hawkins classification of, 771f im agin g of, 771 m echanism of injury, 770 –771 MRI in , 772 physical exam in ation of, 771 presen tation of, 771 treatm en t of, 772 Tarsal coalition , 343 –344, 344f Tarsal tun n el syn drom e cortison e in jection s in , 789

Index differen tial diagn osis of, 789 NSAID in , 789 path ophysiology an d classification of, 788 physical exam in ation of, 788 –789 presen tation of, 788 radiograph ic fin din gs of, 789 special tests for, 789 treatm en t of, 789 Tarsom etatarsal joint, 757 injuries, m an agem ent of, 779 Tartrate-resistant acid ph osphatase (TRAP), 100 T cells, 118 –119 99m Tc-m ethylen e diph osph on ate (MDP), 55 T-con dylar fractures, 416, 417f Techn etium bon e scan s, usage of, 710 Teleoroen tgen ogram , 352, 352f Tendin opath ies, in h an d an d wrist, 644 –646. See also Hand and wrist Tendo calcan eus, 757 Tendon , 25 Tenn is an d golfer’s elbow. See Lateral and m edial epicondylitis Teriparatide, in osteoporosis treatm en t, 107 Terrible triad, defin ition of, 571 Test ch aracteristics, 37 negative predictive value, 37 positive predictive value, 37 sen sitivity, 37 specificity, 37 Testosteron e, 190 Tethered cord, sign s of, 251, 251f Tetracyclin es, 80, 81t Th en ar flap, 613, 615f Thigh –foot an gle, n orm ative values for, 237f Third-body wear, 27 Thoracic outlet syndrom e adson test in , 633 differen tial diagn osis of, 633 path ophysiology/ classification of, 632 physical exam in ation of, 633 presen tation/ m ech anism of in jury, 632 radiograph ic fin din gs of, 633 roos test in, 633 special studies in , 633 treatm en t of, 632 Thoracolum bar fractures, 397 –398 Thoracolum bar spine, fracture dislocation of, 458 –460, 459f–460f. See also Upper cervical spine traum a Thoracolum bar traum a, 452 –458. See also Upper cervical spine traum a burst fractures, 454 –456, 455f chan ce in juries, 456 –458, 457f radiograph ic ch aracteristics of, 457f classification of, 453 compression fractures, 453 –454 stable L3, 454f CT scan in , 453 Thoracolum bosacral orthosis (TLSO), 486 un derarm brace, 365 –366, 366f, 379 Throm boem bolic disease, 747

Thum b carpom etacarpal arthritis, stages I–IV of, 635f Thum b m etacarpal (TM), 583 Thurston –Hollan d fragm en t, 399 Thyroid h orm on e, 10 Tibial em in en ce fractures, 427 –428 classification of, 428, 428f Tibial h em im elia, 289, 290f Tibial n erve, 196 Tibial plateau fractures bum per in juries in , 712 classification of, 712 complication of, 713 differen tial diagn osis of, 713 m ech an ism of injury, 712 patien ts presen tation of, 712 physical exam in ation of, 713 radiograph ic exam in ation of, 713 relevant anatomy of, 713 Sch atzker classification of, 712, 712f special tests for, 713 treatm en t of, 713 Tibial sh aft fractures, 429, 430f, 431 Tibial stress fractures complication s of, 733 differen tial diagn osis of, 732 dreaded black lin e, occurren ce of, 732 m ech an ism of injury, 732 patien ts presen tation of, 732 physical exam in ation of, 732 radiograph ic exam in ation of, 732, 733f relevant anatomy of, 732 special tests for, 732 treatm en t of, 733 Tibial tubercle avulsion s, 428 –429, 429f Tibiofem oral join t, 697 Tidem ark, 11 Tin el test, in CTS, 626 Toron to brace, 327 Torque, 21 Torsion al loadin g, 23 Torsion al or an gular variation , in ch ildren , 235 CT for, 239 differen tial diagn osis, 239 –240 history and physical exam in ation, 236 –237 foot progression an gle, 237, 237f hip rotation , 237, 238f in term alleolar/ in tercon dylar distan ce, 237, 238f patellas poin t an teriorly, 237, 239f th igh –foot an gle, 237, 237f physiology, 235 presen tation , 235 –236, 236f, 237f radiograph s, 239, 239f treatm en t, 240, 240f, 241f Total elbow arth roplasty (TEA), 563 Total h ip arth roplasty (THA), 688 acetabular cup position, 693t cem en ted fem oral fixation , 692, 692f cem en tless implan t fixation , 690 complication s of, 692 –695 excursion distance in, 692 Gluteus Maxim us approach in, 689 Gluteus Medius approach in, 688 –689 head-to-neck ratio, 692

821

h ip implan t design an d m eth ods of fixation , 689 –692 m inim ization of risk for infection in, 694f Moore’s approach in, 689 periprosth etic fracture in , 694f porous tan talum usage in , 690 prin ciples an d h ip stability, 692 screw placem en t, acetabular quadran t system for, 691f Sm ith –Peterson ’s approach in , 688, 689f surgical approach es for, 688 –689 Watson –Jon es’approach in , 688 Total kn ee arth roplasty (TKA), 735, 748f aspirin in, 747 complication s of, 746 –747 coum adin in , 747 CPM m achine, usage of, 746 depuy PFC sigm a, 746f indication s, 744 –745 infection , 747 –748 instability, 749 lateral radiograph of, 749f loosening/ wear, 748 –749 n otch in g of, 750f open reduction in ternal fixation, 751f outcom es of, 746 periprosth etic fracture, 749 –751, 750f polyethylen e compon en t in , 748, 748f postoperative pain , 747 postoperative radiograph of, 745f postoperative recovery, 746 stiffn ess/ arth rofibrosis, 749 surgical procedure, 745 –746 th rom boem bolic disease, 747 tibial sh aft fractures, 751f Total sh oulder arth roplasty (TSA), 545 Tran scutan eous electrical n erve stim ulation (TENS), 486, 641 Tran sien t quadriplegia, 179 Tran sien t syn ovitis, 291 diagn ostic studies, 291, 291f differen tial diagn osis, 291 h istory an d physical exam in ation , 291 path ophysiology, 291 presen tation, 291 treatm en t, 291 Tran sverse atlan tal ligam en t (TAL), 443 Tran sverse carpal ligam en t (TCL), 590 Tran sverse retin acular ligam en t, 588 Tran sverse tarsal join t, 756 Trapeziom etacarpal (TM) arthrodesis, 636 join t classification of, 634 –636 differen tial diagn osis of, 636 presen tation / physical exam in ation of, 636 radiograph ic fin din gs of, 636 treatm en t of, 636 Trapezium fractures. See also Hand an d wrist classification of, 604 m echanism of injury, 604 presen tation an d physical exam in ation , 605

822

Index

Trapezium fractures. See also Hand and wrist (Contd.) radiograph ic fin din gs, 605 treatm en t of, 605 Trapezius, role of, 511 Traum atic amputation , 225 –227 Traum atic un idirection al Ban kart surgery (TUBS), 528 Trem or, 68 Tren delen burg gait, 661. See also Hip and fem ur Trian gular fibrocartilage complex (TFCC), 584 tears of classification of, 609 differen tial diagn osis, 609 m echanism of in jury, 609 presen tation an d physical exam in ation , 609 radiograph ic fin din gs, 609 treatm en t of, 609 Triceps m uscle, 551, 553f Triceps surae, 757 Trigger fin ger differen tial diagn osis of, 644 injection, 644, 644f path ophysiology/ classification of, 644 physical exam in ation of, 644 presen tation of, 644 radiograph ic fin din gs of, 644 treatm en t of, 644 Trim eth oprim -sulfam eth oxazole, 80, 81t Triple in n om in ate osteotomy, 310, 310f Triquetral fractures. See also Hand and wrist classification of, 604 m echanism of in jury, 604 presen tation an d physical exam in ation , 604 radiograph ic fin din gs, 604 treatm en t of, 604 Troch lear groove, 697 Tropocollagen m olecule, 12 Tuberculosis, of spine, 497 –498, 498f m edical m anagem en t of, 498 occurren ce of, 497 Tuberosities, separation of, 502 Tum ors of m usculoskeletal system , 145 ben ign bon e lesion s, 149 –156 ben ign syn ovial proliferative disorders, 162 bon e tum ors, 145 –149 fatty tum ors, 160 fibrous, 160 –161 m alignant bone lesions, 156 –158 myxoid, 161 –162 neural, 162 oth er tum ors, 163 soft-tissue tum ors, 158 –160 treatm en t of, 163 –164, 163t Two-h it th eory, polytraum a, 205 Two-stage exch an ge arth roplasty, 93, 93f Type 1-dependent rickets, 108 Type 2-dependent rickets, 108 Type I collagen, 100

Type I error, 32, 32t Type II collagen, 12 Type II error, 32, 32t

U

Ulnar and radial shaft fractures. See also Han d an d wrist classification of, 608 m echanism of injury, 608 presen tation an d physical exam in ation , 608 radiographic findings, 608 treatm en t of, 608 –609 Ulnar n erve, 194 –195, 410, 415, 594 Ulnar pole, 584. See also Han d an d wrist Ulnar seat, 584. See also Han d an d wrist Uln ar tran slation , 610 Ulnar tunnel syndrom e differen tial diagn osis of, 630 path ophysiology of, 631 presen tation / physical exam in ation of, 631 special studies in, 631 treatm en t of, 630 –631 Ulnocarpal abutm ent syndrom e, 609 Ulnohum eral join t, function of, 549 Ultra high m olecular weight polyethylene (UHMWPE), 26, 26f Ultrasound, 53 clin ical application of, 53 drawback of, 53 ligam entous structures, evaluation of, 53 –54 for pediatric patien ts, 54 soft-tissue m ass lesion s and, 54 Ultrasound evaluation , of shoulder, 519 –520. See also Sh oulder Un icompartm en tal kn ee arth roplasty (UKA), 743 –744 advantage of, 743 of th e m edial com partm en t, 744f Un iversity of Californ ia Biom ech an ics Laboratory (UCBL), 784 Un iversity of Pen n sylvan ia System for Stagin g Avascular Necrosis, 695t, 696 Upper cervical spin e traum a atlas, C1 rin g injury-fractures of, 443 –444 axis, traum atic spondylolisthesis of, 446 –448 cran iocervical dissociation , 443 facet subluxation an d dislocation , 451 –452 Jefferson fracture, 444, 444f odon toid fractures, 444 –446 subaxial cervical spine traum a, 448 th oracolum bar spin e, fracture dislocation of, 458 –460, 459f–460f th oracolum bar traum a, 452 –458 vertebral body fractures, 448 –451 U.S. Food and Drug Adm in istration (USFDA), 59

V

Valgus osteotomy, of proxim al fem ur, 330, 330f Valgus stress test, 571 –572 Valvular disease, 183 Van comycin , 80, 81t Van couver’s classification , of periprosth etic fem oral fractures, 694t Van Nes rotationplasty, 287, 287f Variables, 29 con foun ders, 30 depen den t variables, 30 in depen den t variables, 29 –30 Vastus m edialis obliquis (VMO), 708 Vertebral body fractures, 448 –451. See also Upper cervical spine traum a burst fractures, 449 compression fractures, 449 Vertebral colum n , progressive differen tiation of, 6f Vertebral osteomyelitis, 496 Vertebra plan a, 152 Virulen ce, 79 Viscoelastic m aterial, 24 creep, 24 dampin g, 24 relaxation, 24 Visual an alog scales, 38 Vitam in D, 98 –99 m etabolism , 99f Vitam in D –depen den t rickets, 261. See also Rickets Volar in tercalated segm en t in stability (VISI), 610 Volar plates, fun ction of, 584 Volar radiocarpal ligam en ts, 585f Von Recklin gh ausen ’s disease, 162

W

Wackenh eim ’s line, 441. See also Cervical spin e Wartenberg syndrom e path ophysiology of, 632 physical exam in ation of, 632 presen tation of, 632 special studies in , 632 treatm en t of, 632 Wear, 27, 27f Weber classification system , of an kle fractures, 763, 763f Weigh t, 21 White blood cell (WBC), 494, 558 coun t, 82 Wilcoxin Sign ed-Ran k test, 30 Wolfe’s law, 15 Woven bon e, 15 Wrist, exten sor compartm ents of, 587t Wrist fusion , radiographs of healed, 637, 637f

Z

Z-len gthening of Ach illes tendon, 247, 247f

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