Dr.Harry Sunaryo SpOT
Legg-Calve-Perthes disease was originally described independentlyin 1910 by Legg of the UnitedStates, Calve of France, and Perthesof Germany. The condition is a diseaseof children in which the essentiallesion is not simply ischemia,but also includes the resultingprocess of resorption, collapse, andrepair, which may result in apainful, poorly functioning hip.The majority of patients do wellinto their fifth decade; however, inone long-term study of untreatedpatients, 50% had disabling arthritisby age 55.1 Treatment is largelya matter of the physicianÕs personalpreference, as the literature offers little scientific evidence to suggestsuperiority of one treatment over another or even to conclusivelyestablish the efficacy of any treatment over the natural history of thedisease.PathogenesisBiopsy studies have established thatvarious stages of bone necrosis andrepair are present in the femoralhead in Legg-CalvŽ-Perthes disease.However, numerous experiments inwhich the blood supply to thefemoral head was interrupted in asingle event failed to produce thecharacteristic lesion of Legg-CalvŽ-Perthes disease. Other researchershave found that recurrent injury tothe circumflex arteries in dogs mimicsthe appearance of the disease,suggesting that Legg-CalvŽ-Perthesdisease occurs over time with repetitiveinjury. The dependence of theblood supply to the femoral head onretinacular vessels that coursethrough a nondistensible intracapsularspace makes the theory ofischemia secondary to tamponadepersuasive. Nevertheless, althoughartificially elevated intracapsularhip pressure and increased intraosseousvenous pressure have beenshown to produce femoral headischemia in animals experimentally,they have not been directly linked toLegg-CalvŽ-Perthes disease inhumans. Furthermore, ultrasoundevaluation of 4- to 8-year-old boyswith early Legg-CalvŽ-Perthes diseasemanifested by groin pain andlimited hip motion also failed to confirmthe presence of capsular distention.2More recently, clotting factorsand increased blood viscosity havebeen implicated as potential causes.Gregosiewicz et al2 examined theserum of 26 boys with early Legg-CalvŽ-Perthes disease and found asignificantly greater level of a1-antitrypsinthan in control subjects, indicatinga decrease in fibrinolyticactivity and enhanced intravascularclotting.A possible relationship betweenendocrine abnormalities, especiallythyroid disorders, and Legg-CalvŽ-
AbstractLegg-CalvŽ-Perthes disease is a self-limited disease of the femoral head that presentsin the first decade. The pathogenesis is thought to involve bone necrosis,collapse, and repair. The presenting complaint is often a painless limp or hippain, with decreased abduction and internal rotation of the hip. Factors that arebelieved to correlate with a poor prognosis are onset of symptoms after age 8years, lateral head subluxation, involvement of over 50% of the femoral head withcollapse of the lateral pillar, and the combination of an aspherical femoral headand an incongruent joint. The current cornerstones of treatment are maintenanceof hip motion, relief of symptoms, and containment. Containment may beachieved by bracing or surgical means. The literature remains inconclusive onthe indications for and effects of treatment. A long-term study has suggested thatdisabling arthritis of the hip develops in the sixth decade of life in 50% ofuntreated patients.J Am Acad Orthop Surg 1996;4:9-16Perthes disease has also been studied.In a large recent study,3 it wasfound that although children withLegg-CalvŽ-Perthes disease areeuthyroid, they have significantlyhigher levels of free thyroxine andfree triiodothyronine than controlsubjects. In addition, there was a statisticallysignificant increase in freethyroxine levels with an increasingdegree of femoral-head involvement.Earlier work by the sameinvestigators had shown that plasmalevels of insulin-like growth factor Iwere reduced early in Legg-CalvŽ-Perthes disease.Histologic evaluation of femoralheadspecimens from patients withLegg-CalvŽ-Perthes disease showsnecrosis at different stages of repair.In specimens from 11 children,Catterall et al4 found three stages ofthe disease process. In the initialstage, bone necrosis predominatesfrom the physis to the subchondralcartilage-bone interface. Femoralheadossification is stopped, whilethe articular cartilage, nourished bysynovial fluid, continues to grow,resulting in the radiographicappearance of a small ossific nucleuswith a widened cartilage space. Inthe second stage, resorption ofnecrotic bone and creeping substitutionof the necrotic bone by vascularconnective tissue occur slowly overa 1- to 3-year period. The third stageis characterized by the appearance ofosteoblasts, followed by new-boneformation and healing. This stage isprobably concurrent with revascularization.Collapse of the necrotic subchondralbone leads to loss of femoralheadheight, as well as hip pain andsynovitis. After collapse, a renewedcycle of bone resorption and repairbegins. Some authors believe thereare no symptoms until a subchondralpathologic fracture occurs andthat, without collapse, ÒsilentÓinfarcts may result in nothing morethan a growth-arrest line or a Òheadwithin-a-headÓ radiographic appearance.However, in their study,Salter and Thompson5 found that77% of children with Legg-CalvŽ-Perthes disease did not have evidenceof subchondral fractures onradiographs obtained at the time ofdiagnosis.The collapse of a subchondral fracturecan lead to flattening of the ossificregion of the femoral head. The articularcartilage remains intact initially.Healing usually results, with coxamagna. Growth disturbances willoccasionally occur if isolated areas ofthe physis are affected. Physealinvolvement is variable, but the anteriorportion of the physis is most commonlyaffected. As the disease issecondary to multiple infarcts of varyingage, multiple stages of infarctionor repair may be present at any onetime. It is interesting that Catterall etal4 also found that the unaffected hipdemonstrates thickening of the articularcartilage with irregular staining, aswell as thinner physeal cartilage withirregular cell columns, suggestingthat some preexisting condition contributesto susceptibility to Legg-CalvŽ-Perthes disease.We do not recommend routinelaboratory tests for endocrine orhematopoietic disorders in otherwisehealthy children with Legg-CalvŽ-Perthes disease.Clinical PresentationThe usual age at presentation is 4 to10 years. The condition is more frequentin boys than in girls, andaffected children are often small fortheir age. The child usually haslimped for a few weeks or months.There is often no pain; when present,pain is usually mild and can affectthe knee. Because the hip is innervatedby three nerves, the pain maybe referred to the suprapatellarregion (femoral nerve), the medialthigh (obturator nerve), or the buttock(sciatic nerve). In many cases,diagnosis is delayed due to failure toexamine the hip when the patientcomplains of knee pain. Somepatients report having sufferedacute trauma when the pain started.Limited internal rotation andabduction of the hip are the most consistentfindings. Limitation of internalrotation is best tested with the hipin extension. Limited hip motionearly in the disease is due to musclespasm and synovitis; late in the disease,it may be due to bone impingementof the femoral head on theacetabulum. Gait may be antalgicand may exhibit a gluteus mediuslurch. The Trendelenburg test isoften positive, and quadriceps atrophyin the affected leg is common.The affected leg may appear significantlyshorter due to an adductioncontracture; however, significantshortening is not common unlesssevere coxa plana has developed.Radiologic Evaluation andStagingThe diagnosis is generally made andthe course of the disease is followedwith anteroposterior and frog-leglateral radiographs of the pelvis.The child often has a delayed boneage. When the condition is bilateral,which occurs in 10% to 20% of cases,the hips may be at different stages.The first radiograph should beobtained without the use of a shield,to exclude the presence of pelvicabnormalities.The radiographic appearance ofLegg-CalvŽ-Perthes disease may bemimicked by other conditions,including multiple epiphyseal dysplasia,spondyloepiphyseal dysplasia,thyroid disease, GaucherÕsdisease, and trichorhinophalangealsyndrome, as well as by corticosteroidusage. Numerous radiologicsigns and classification systems havebeen described.10 Journal of the American Academy of Orthopaedic SurgeonsLegg-Calvé-Perthes DiseaseWaldenstrom classified radiologicfindings on the basis of the evolutionaryphase of the disease. Initially, thefemoral head is radiodense andsmaller, while the cartilage space ofthe hip is wider. The increased radiodensityoccurs because the surroundingbone has a normal blood supply,thus appearing osteopenic comparedwith the avascular segment. After asubchondral fracture, the fragmentationstage follows. The radiographicappearance of lateral fragmentationof the femoral epiphysis is caused byongoing necrotic bone resorption andnew-bone formation. This leads intothe healing phase, when furtherreossification occurs and radiodensitybecomes normal. The residualdeformity may be coxa magna, coxaplana, or coxa breva. TheWaldenstrom classification demonstrateswhich stage of the disease ispresent, but has no predictive valuefor long-term outcome or treatment.The Catterall classification ,which is the most commonly used,defines four groups, primarily on thebasis of the amount of involvementof the femoral head and the presenceof radiographic Òat riskÓ signs.6Group I shows anterior centralinvolvement of the head and nometaphyseal reaction. Group II shows about 50% involvementanterolaterally, with the medial andlateral-pillar portions of the femoralhead intact, plus anterolateral metaphyseallesions. In group III, about75% of the head is involved, includingthe lateral column, with diffusemetaphyseal reaction. In group IV, 1 The Catterall classification of Legg-CalvŽ-Perthes disease. In group I there is involvement (hatched areas) of the anterior head only,no sequestrum, and no collapse of the epiphysis. In group II, only the anterior head is involved, and there is a sequestrum with a clear junction.In group III only a small part of the epiphysis is not involved. In group IV there is total head involvement.the entire head is involved, with diffuseor central metaphyseal reaction.Catterall suggested that groups I andII have favorable outcomes withouttreatment, while groups III and IVhave a poorer prognosis and requiretreatment. Initially established froma retrospective review, the Catterallclassification has the disadvantagethat the appropriate group designationmay appear to change as the diseaseproceeds.After reviewing the radiographs of1,264 children with Legg-CalvŽ-Perthes disease, Salter and Thompson5concluded that the extent of the subchondralfracture correlated preciselywith the subsequent extent of maximumresorption, potentially providingan early means of predicting theeventual extent of femoral-headinvolvement. The subchondral fracture,or Òcrescent sign,Ó is a transientphenomenon in the early stages of thedisease, lasting 2 to 9 months.Radiographic visualization of such afracture may herald the onset of symptomsin a previously asymptomaticprocess.The Salter-Thompson classificationis based on the extent of subchondralfracture. In group A, less than half ofthe femoral head is involved; in groupB, more than half of the femoral headis involved. The advantages of thisclassification system are early applicabilityand simplicity. The major disadvantageof the Salter-Thompsonclassification is that 77% of the patientsin their series did not have radiographsshowing a subchondral fracture.As the study was retrospective,it was not possible to obtain replacementsfor poor-quality radiographs,which might have been more likely toshow a crescent sign. Despite theirdrawbacks, both the Catterall andSalter-Thompson classifications seemto have prognostic value.7A relatively new classification hasbeen proposed by Herring et al8(Fig. 2). On an anteroposteriorradiograph of the pelvis obtained inthe early fragmentation phase, theheight of the lateral epiphyseal pillaris compared with the height of thenormal contralateral epiphysis. Ingroup A, there is no collapse of thelateral pillar. In group B, the lateralpillar maintains at least 50% of itsoriginal height. In group C, there iscollapse of the lateral pillar, withloss of more than 50% of its originalheight. In a retrospective analysis,no hip in group A had progressivefemoral-head flattening, while onlythe oldest patients in group B (meanage at onset of disease, 10 years) hada flattened femoral head. Patients ingroup C were most likely to exhibitprogressive flattening during reossification(incidence, 17%). This studyalso showed that, contrary to previousbelief, the femoral head maycontinue to deform during the 3- to4-year period of reossification.Ritterbusch et al9 compared theHerring lateral-pillar classificationand the Catterall classification andfound that the lateral-pillar classificationwas a better predictor of longtermoutcome and had greaterinterobserver reliability. We currentlyfavor the lateral-pillar classification.Other Imaging StudiesThe initial radiographic changes ofLegg-CalvŽ-Perthes disease may beabsent at the onset of symptoms.Technetium-99m bone scanningwith use of a pin-hole collimatormay allow earlier diagnosis thanradiography. Early in the course ofthe disease, a bone scan displaysÒcold spots,Ó representing avascularareas that involve a significant partof the femoral head, while thefemoral physis and acetabular rimshow normal radioisotope uptake.During revascularization, thefemoral head demonstrates increasedisotope uptake.Revascularization of bone can occurby recanalization of existing vesselsor by neovascularization throughthe development of new vessels.Recanalization occurs rapidly (minutesto weeks), whereas neovascularizationis a prolonged process(months to years). The bone-scan12 Journal of the American Academy of Orthopaedic SurgeonsLegg-Calvé-Perthes DiseaseGroup A Group B Group CFig. 2 The Herring classification of Legg-CalvŽ-Perthes disease. In group A, the lateral pillarretains its original height and shows slight radiographic changes. In group B, the lateralpillar may show density changes and height loss, but retains at least 50% of its originalheight. In group C, the lateral pillar is characterized by radiolucencies and collapse to lessthan 50% of its original height.pattern of revascularization thatbegins with visualization of the lateralepiphyseal column appears torepresent recanalization of themedial circumflex artery. Thisprocess occurs relatively rapidly andcarries a good prognosis. A scintigraphicappearance of base filling,indicating extension of radioactivitythrough the growth plate into thebase of the epiphysis by new vessels,represents neovascularization,which carries a poorer prognosis.10Magnetic resonance (MR) imagingmay depict bone infarctionbefore radiography does. In addition,MR imaging provides directvisualization of articular and physealcartilage and can be used to estimatefemoral-head sphericity betterthan radiography. However, MRimaging has not proved advantageousover radiography for seriallyfollowing the disease process and iscertainly more expensive. As allstudies to date are based on radiographiccriteria, it is unclear at thistime whether bone-scan or MRchanges warrant treatment.Arthrography is an excellentdynamic study in that it allows visualizationof femoral-head shape andhip-joint congruency through thefull range of motion of the hip.Arthrography can demonstrate thebest position for containment if thefemoral head is congruent and candepict the presence of hinge abductionif the femoral head is deformed.Natural HistoryMost reviews of patients with Legg-CalvŽ-Perthes disease have theinherent problems of retrospectivereviews, including grouping of varioustreatments and degrees of diseaseseverity. However, in follow-upstudies into late middle age ofpatients with Catterall group II, III,or IV disease, 70% to 90% wereactive and free of significant pain,with good range of motion, althoughtheir radiographs were often abnormal.Typical of these studies is thatby Gower and Johnston.11 Theyevaluated 36 patients (average age,45 years) 36 years after the onset ofsymptoms of Legg-CalvŽ-Perthesdisease. Of the 30 patients who weretreated nonoperatively, 86% hadscores on the Iowa Hip Rating Scaleof more than 80 points, and 8% hadbeen treated with arthroplasty.This same group of patients waslater reexamined by McAndrew andWeinstein,1 when the patients had anaverage age of 55 years. The numberof patients with Iowa hip scores over80 points had fallen to 40%. Forty percentof the patients had undergonetotal hip arthroplasty, and an additional10% had disabling osteoarthritis.A strong correlation between lossin width of the joint space (as seenradiographically) and the change inthe Iowa hip score was noted. Othermeasurements of femoral-head andacetabular deformity and congruencyhad not changed over this follow-upperiod. It was concluded that theobserved deterioration in functioncould be attributed solely to the onsetof osteoarthritis.It should be noted that these twostudies evaluated the results of noncontainmenttreatment. No similarlong-term studies after containmenttreatment have been published.PrognosisA number of radiographic at-risksigns that have been discusseddeserve brief mention. Catterall proposedthat patients are at risk for apoor prognosis if the followingradiographic findings are present:GageÕs sign (a radiolucent ÒVÓ onthe lateral side of the epiphysis), calcificationlateral to the epiphysis, lateralsubluxation of the femoral head,a horizontal physis, and metaphysealcysts. Some authors have consideredÒmetaphysealÓ cysts to beepiphyseal changes superimposedon the metaphysis by three-dimensionalradiographic distortion.12While these authors also argue thatthere has never been clinical oranatomic confirmation of metaphysealcysts, Catterall6 found metaphyseallesions consisting of nonossifiedcartilage in autopsy studies.While Òhead at riskÓ signs havebeen thought to be prognostic indicators,two recent reports, eachinvolving 100 patients, concludedthat no head-at-risk sign other thanlateral subluxation was important asa prognostic indicator.7,13 In a longtermfollow-up study, McAndrewand Weinstein1 found that three radiologicmeasurements correlated witha poor clinical outcome: two or moreCatterall head-at-risk signs, coxamagna (in which the femoral head islarger than normal by 10% or more,as described by Stulberg et al14), anda decrease in joint space in later life.1Coxa magna, coxa breva resultingfrom growth arrest, coxa plana, andacetabular deformities are associatedwith healed Legg-CalvŽ-Perthes disease. Stulberg et al14correlated the radiographic deformityof the femoral head at skeletalmaturity with the eventual functionaloutcome. Femoral heads thatwere flat yet congruent with theacetabulum were at risk for arthritisin the sixth decade of life. As thenormal ball-and-socket joint deformsto a flattened cylinder, the hiploses abduction and rotation capability,while retaining flexion andextension potential. If the femoralhead is flat and is not concentric withthe acetabulum, early severe arthritisoccurs. Hinge abduction andanterior impingement are knownsequelae of a flat, incongruentfemoral head.One of the most important prognosticindicators is limitation of hipmotion. In the initial stages of thedisease, synovitis is responsible loss of hip motion. If the hip remainsstiff for a prolonged period, deformationof the hip joint may develop.Long-term studies have shown thatthe earlier the onset of the disease,the better the long-term prognosis.The age of 6 to 8 years appears to bethe dividing line,1,14 perhaps becausethe acetabulum and femoral headlose some remodeling potential asthe child ages.Salter and Thompson5 found nosignificant difference in outcomebetween Catterall groups I and II(satisfactory outcomes in 100% and93% of patients, respectively) butnoted worse results in group III hips(60% to 76% satisfactory) and groupIV hips (41% to 61% satisfactory).This study appears to support thetreatment of Catterall group III andIV hips but only observation ofgroup I and II hips.Another prognostic indicatorinvolves the lateral pillar. Becausethe intact lateral column protects theepiphysis, it has been shown to be afavorable prognostic indicator.5,8,9TreatmentEarly treatment of Legg-CalvŽ-Perthes disease focused on relieffrom weight-bearing until thefemoral head had reossified.Prolonged bed rest, traction, spicacasts, and special frames and slingswere used, but the results of treatmentwere difficult to assess accurately.The results of current Legg-CalvŽ-Perthes treatment are difficultto evaluate. It is still uncertain whoneeds treatment and who does not.The most commonly used classificationsystem, that of Catterall, mayhave high interobserver variation.In the studies published to date,there is a lack of uniformity of criteriafor selection, treatment, and evaluation,and, more important, thereare few control studies.15 In addition,no studies reported to datehave been prospective or randomized,although a multicenter prospectivestudy is currently ongoing.In a recently published in-depthreview of the literature on Legg-CalvŽ-Perthes management,Herring15 cited the inconclusivenessof the findings.Today, maintenance of hip motionand containment of the involvedfemoral head form the bases for treatmentof Legg-CalvŽ-Perthes disease.However, the 80% good results in a22-year follow-up at an institutionwhere noncontainment treatmentwith a weight-relieving sling or harnesswas used16 have been as good asany reported.The initial goal of treatment is torestore hip mobility and relievepain. The next step is to decide whatpercentage of the femoral head isinvolved and whether active treatmentwill be needed. Containmenttreatment should not begin untilabduction and internal rotation havebeen restored to a near-normal state.Several days of bed rest at home or inthe hospital may be needed toreduce the symptoms. Traction maybe used to help keep the child off hisor her feet. Physical therapy often isuseful to help maintain hip motion.Adductor tenotomy or serial Petrieabduction casts may be necessary inmore resistant cases.Once hip mobility has improved,containment treatment can be considered.The theory behind containmentis that development of a congruentjoint is dependent on maximal contactbetween the immature femoral headand acetabulum. This theory hasbeen proved clinically and in the laboratoryin developmental dysplasiaof the hips, although the results forLegg-CalvŽ-Perthes disease remainsomewhat difficult to interpret.Before beginning any form of containmenttreatment, it is essential to makecertain that the hips can be containedcongruently and that there is no hingeabduction due to femoral-head flattening.Arthrography is particularlyuseful if abduction radiographs takenin the position of proposed containmentare equivocal.For the purpose of discussion, wewill divide Legg-CalvŽ-Perthes diseasepatients into two categories onthe basis of the extent of involvementof the femoral head. Childrenwith less femoral-head involvementare those with Catterall group I or II,Salter-Thompson group A, orHerring type A or B disease. Themajority of these patients have excellentresults regardless of the type oftreatment or lack thereof. Childrenwith more femoral-head involvement(i.e., those with Catterall groupIII or IV, Salter-Thompson group B,or Herring type C disease) oftenhave later disability if untreated.Maintenance of hip range of motionis probably all the treatmentrequired for patients with lessinvolvement, especially those under6 years of age. No containmenttreatment is indicated unless thereare poor prognostic indicators, suchas persistent or recurrent synovitis,lateral subluxation, involvement ofthe lateral pillar, or involvement ofnearly 50% of the femoral head. Werecommend some form of containmenttreatment for most childrenaged 6 years or older in whom thereare more than two poor prognosticindicators. Children with moreinvolvement should receive containmenttreatment. Our preference is touse bracing for children under 7years and surgical containment forthose over 7 years.Nonoperative ContainmentContainment methods that prohibithip motion, such as the use ofspica casts, are not recommended.Motion is a prerequisite for containmenttreatment and cannot beoveremphasized during the courseof treatment. Petrie casts (two longlegcasts separated by an abduction14 Journal of the American Academy of Orthopaedic SurgeonsLegg-Calvé-Perthes Diseasebar) have been used as a means ofcontainment, although medialfemoral condyle flattening has beendescribed with prolonged use.These and other long-leg orthosespromote abduction while allowingmotion at the hip and ambulation.Petrie casts have been largelysuperseded by shorter orthoses. Themost popular of these is the Scottish-Rite Hospital orthosis, which consistsof two thigh cuffs connected byan abduction bar, with joints toallow motion at the hips and knees,promote ambulation, and containthe femoral head. It is generally welltolerated by patients under 7 yearsand well accepted by their parents.Deciding when to remove the braceis a problem, as there is no clear evidenceshowing when containmentceases to be beneficial. The patient isgenerally weaned off use of theorthosis when radiographs showthat the disease is in the reparativestage, as shown by reossification ofthe lateral epiphysis.15 Althoughtwo recent reviews of the use of theScottish-Rite Hospital orthosis inpatients with Catterall group III orIV disease (mean age at diagnosis, 6and 7 years) failed to show anyadvantage over either no treatmentor other means of treatment,17,18 thepossibility of avoiding surgery hasled many pediatric orthopaedists tocontinue to use this device inyounger children with Legg-CalvŽ-Perthes disease.Operative ContainmentThe relative advantages of operativeover nonoperative treatment arealso unclear. Many have reportedthat operative treatment provides animproved outcome compared withthe natural history in children withmore extensive femoral-headinvolvement, although rigorouscontrols have been lacking. A comparativestudy of varus-derotationosteotomy and ambulation-abductionbracing in children over 6 yearsrevealed no difference in results.19Surgical containment can beachieved by proximal femoral varusosteotomy, innominate osteotomy,an acetabular-shelf procedure, orsome combination of femoral andpelvic procedures. However, itmust be remembered that in a normalhip the femoral head is only 63%Òcontained,Ó as the femoral head is120% of a hemisphere while theacetabulum is 75% of a hemisphere.20 Furthermore, which 63%of the femoral head is in contact withthe acetabulum is a function of thephase of gait as the joint changesposition. One review of 72 patientstreated with a femoral or innominateosteotomy disclosed no difference inresults at follow-up.21 There are theusual risks of surgery, and a secondoperation is often necessary toremove hardware. The advantagesof surgery include definitive treatment,a short period of limited activity,and the avoidance of psychosocialissues arising from prolonged bracewearing.Salter22 recommends the innominateosteotomy for children 6 yearsor older with Salter-Thompsongroup B involvement and subluxationof the femoral head in a weightbearingposition. His recommendedcriteria for surgery are pain-free fullrange of motion of the hip and nodeformation of the femoral head.While studies of the innominateosteotomy may have slightly betterresults than other surgical series, it islikely due to the above-mentionedselection criteria. The Salter innominateosteotomy provides a practicallimit of 25 degrees of anterior coverageand a range in lateral coverage of5 degrees at heel strike to 15 degreesat midstance, with an increase inanterior coverage at the expense ofless posterior coverage.20 To ensurepreservation of motion, a psoas andpartial-adductor tenotomy shouldaccompany the procedure, a postoperativehip spica cast should beavoided, and physical therapyshould be begun early.Varus-derotation osteotomy ofthe proximal femur may providecontainment if an abduction-internalrotation radiograph of the hip showscontainment. A dynamic arthrogramis recommended to find thebest position, as the osteotomy cancorrect for rotation, varus/valgus,and flexion/extension as needed.Varus correction should be limited to20 degrees, because complicationssuch as a short leg and abductorlurch are more pronounced withgreater varus angulation, althoughboth usually improve with time.One may expect 15 to 20 degrees ofincreased lateral coverage and about10 degrees of improved anterior coveragefrom a 15-degree-varus, 15-degree-derotation osteotomy of theproximal femur. While this osteotomytheoretically doubles theshear force across the proximalfemoral physis,19 adverse clinicaleffects have not been reported.As there are limitations to theamount of femoral-head coveragethat can be obtained with bothinnominate and intertrochantericosteotomies, a combined proceduremay be indicated in severe subluxation.Theoretically, the potentiallengthening and increased joint pressureresulting from an innominateosteotomy may be avoided by performingan intertrochanteric osteotomy,which provides both shorteningand a decrease in joint-surface pressure.Both osteotomies may be performedthrough a single ilioinguinalapproach or through separate incisions.Use of this combination hasbeen reported in patients withCatterall group III or IV involvement;seven of nine patients had clinicallygood results after a mean follow-upperiod of 50 months.23Shelf arthroplasty has been recommendedfor children over the ageof 8 years who have Catterall II, III, or IV disease, to prevent subluxationand increase acetabularcoverage. Compared with an agematchedcontrol group treated nonoperatively,patients who underwenta shelf arthroplasty had better hipmotion and coverage 2 years aftersurgery.24 Hardware removal is notneeded with this procedure.Hinge abduction occurs laterwhen an enlarged femoral head is laterallyextruded and impinges againstthe lateral acetabular rim on abduction,causing pain. A medial dye poolis seen on arthrography. A valgusosteotomy is indicated if arthrographyshows congruence of the medialfemoral head with the acetabulum asthe hip is adducted, provided a functionalamount of adduction wouldremain after the osteotomy. Chiariosteotomies performed as salvageprocedures in the older child with littleremodeling potential serve toincrease the load-bearing area, whichmay offer several years of pain-freehip function before further reconstructivesurgery is needed.SummaryAlthough the literature is inconclusiveon indications for treatment andwhat type of treatment to use, somerecommendations seem warranted.Regaining and preserving hipmotion cannot be overstressed andis certainly indicated before any containmenttreatment. Poor prognosticfactors include the onset ofsymptoms after age 8 years, lateralhip subluxation, involvement ofmore than 50% of the femoral headwith collapse of the lateral pillar,and an aspherical femoral head withan incongruent joint. In the presenceof any of these factors, it is unlikelythat containment treatment willharm the patient, and it certainlymay help. As long-term studieshave shown that in 50% of untreatedpatients disabling arthritis of the hipdevelops in the sixth decade of life, Legg-Calvé-Perthes Disease
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