surgical treatment of subluxation and dislocation of the hips in ...

C.T. Wu, S.C. Huang, and C.H. ChangSURGICAL TREATMENT OFSUBLUXATION AND DISLOCATION OF THE HIPS INCEREBRAL PALSY PATIENTSChung-Ting Wu, Shier-Chieg Huang, 1 and Chia-Hsieh Chang 2Background and Purpose: Progressive subluxation and dislocation of the hip are majorcomplications in patients with cerebral palsy (CP), causing functional deteriorationand difficulties in personal hygiene. Treatment of these problems is difficult andcomplicated. The purpose of this study was to describe the surgical results and longtermfollow-up in a group of CP patients.Methods: Twenty-three CP patients with subluxated (15 hips) or dislocated hips (12hips) underwent corrective surgery between 1985 and 1993. This included 11quadriplegic, eight diplegic, and four hemiplegic patients. Before surgery, fourpatients were bed-ridden, eight were sitters, six were house-ambulators, and five werecommunity-ambulators. The average age at surgery was 8 years and 5 months. Thesurgical procedures consisted of femoral varus derotational osteotomy in 21 patients(25 hips), selected soft tissue release in 18 patients (22 hips), and pelvic osteotomyin 18 patients (20 hips). The center–edge angle, acetabular index, and neck–shaftangle were used as parameters to evaluate preoperative and postoperative radiographicchanges.Results: After an average follow-up of 4.8 years, 19 patients (22 hips) had gainedhip stability, and also had improved functional status. The four bed-ridden patientsall became sitters; six of the eight sitters became house-ambulators and one becamea community-ambulator; all six house-ambulators became community-ambulators,and the five community-ambulators had functional improvement. Complicationsincluded nonunion at the femoral osteotomy site in one hip, redislocation in twohips, and resubluxation in one hip.Conclusions: We conclude that subluxated or dislocated hips in patients with CP canbe effectively treated with aggressive correction, which may include soft tissue release,femoral derotational osteotomy, and pelvic osteotomy for improvement of hip rangeof motion and functional status.(J Formos Med Assoc2001;100:250–6)Key words:cerebral palsysubluxationdislocationhipsurgeryHip deformity is the second most common deformityin cerebral palsy (CP) patients, following equinus deformityof the foot. Usually, CP patients have normalhip anatomy at birth, then spastic adductors and iliopsoasbegin to be noted at about 6 to 18 months of age.Spastic muscle imbalance fosters retention of fetalskeletal anatomy, and the absence of normal motionand weight bearing contribute to acetabular deficiency.Spastic hip flexors, adductors, and internal rotatorsoverpower their antagonists and eventually cause muscleshortening and a fixed flexion-adduction contractureof the hip joint [1]. In general, hip subluxation in CPpatients develops at about 3 years of age, and dislocationat about 7 to 8 years of age [2]. For neurologicallyimmature, spastic, quadriplegic children, the prevalenceof hip dislocation approaches 50% [3]. If leftuntreated, this situation can adversely influence thepatient’s sitting balance or decrease sitting tolerance.Department of Orthopedic Surgery, En Chu Kong Hospital, Taipei, 1 Department of Orthopedic Surgery, National TaiwanUniversity Hospital, Taipei, 2 Department of Orthopedic Surgery, Chang Gung Memorial Hospital, Taoyuan.Received: 19 June 2000. Revised: 27 October 2000. Accepted: 6 February 2001.Reprint requests and correspondence to: Dr. Shier-Chieg Huang, Department of Orthopedic Surgery, Taipei Hospital,Department of Health, The Executive Yuan, ROC, 127 Su-Yuan Road, Hsin-Chuang City, Taipei County, Taiwan.250J Formos Med Assoc 2001 • Vol 100 • No 4

Surgery for Hip Dislocation in Cerebral PalsyAn unbalanced trunk can further compromise thepatient’s upright posture and decrease the ability touse the upper extremities, necessitating custom seatingmodifications. Windblown posture might be acquiredin severe cases. Pain is also a major issue in upto 50% of untreated hip dislocations [4]. Perinealhygiene is difficult, and pressure sores may appear, addingto the patient’s misery and the cost of care [1, 5].Prophylactic treatment aimed at normal developmentof the acetabulum should be performed as soonas the deformity is diagnosed. Various kinds of surgicalprocedures, including soft tissue release and boneprocedures [6, 7], have been advocated. Since CPpatients have a wide variety of clinical manifestationsdepending on causative factors and timing, many proceduresmay be combined according to the adaptivechanges that have occurred around the hip joints. Thepurpose of this study was to describe the results ofaggressive, comprehensive treatment of subluxationand dislocation of the hips in a series of CP patients.Materials and MethodsA total of 23 CP patients underwent surgery for correctionof subluxated or dislocated hips at National TaiwanUniversity Hospital during the period from 1985to 1993. There were nine boys and 14 girls. Twenty-twopatients had spastic CP, and one had mixed spasticathetoidCP (Case 23). Eleven patients were quadriplegic,eight diplegic, and four hemiplegic. The righthip was involved in 10 patients, left in nine, and both infour. There were 15 subluxated and 12 dislocated hips.Walking ability, range of motion (ROM), and painlevel were recorded preoperatively and postoperatively.Before surgery, five patients were communityambulators, six patients house-ambulators, eight patientssitters, and four patients were bed-ridden. Allpatients had decreased abduction and extension of thehips. Five patients had hip pain.The preoperative and final radiographic evaluationwas based on the center–edge angle (CEA), acetabularindex (AI), and neck–shaft angle (NSA). For the 15subluxated hips, the CEA was –4° on average (range,–40°–30°), the AI was 28° (range, 19°–38°), and theNSA was 156° (range, 114°–140°). For the 12 dislocatedhips, the CEA was –78° on average (range, –150°to–35°), the AI was 33° (range, 25°–43°), and the NSA was170° (range, 150°–197°).Surgery was suggested when the adductor musclecontracture prohibited 30° of hip abduction, or when45° flexion contracture of the hip was present, or bothoccurred together. The goal of the operation was toimprove the hip ROM, increase abduction to at least45°, and decrease flexion contracture to no more than30°. The mean age of patients at the time of surgery was7 years 5 months (range, 1 yr 8 mo–14 yr 5 mo). Releaseof soft tissue including adductors, iliopsoas, andhamstrings, was only used in combination with otherprocedures. Varus derotational osteotomy (VDO) wasperformed in all but two patients with deformity of theproximal femur. This procedure was indicated when amarked break in the Shenoton line, a CEA of 10° orless, and increased coxa valga and anteversion werepresent, as advocated by Mubarak et al for three-leveltreatment for CP hips [8]. Open reduction was alsoperformed for hips in which concentric reductioncould not be obtained by closed means. In cases withhigh dislocation or severe joint contracture, femoralshortening was performed. The subtrochanteric osteotomywas fixed with a 90° blade plate. Pelvic osteotomywas performed in all patients with acetabulardysplasia (AI > 30°). All but five patients underwent thisprocedure. The Dega procedure was used in five patients(Fig. 1), Salter osteotomy in five, Pembertonosteotomy in four (Fig. 2), and triple osteotomy in four.The choice of pelvic osteotomy was based on the age ofthe patient and the severity of hip deficiency; Salterosteotomy was indicated for children aged between 18months and 6 years old, and Pemberton osteotomy orSteel osteotomy for children aged 18 months to 10years old with more than 10–15° correction of AI. Degaosteotomy was indicated for older patients.Student’s t-test was used to compare radiographicvalues before and after surgery.ResultsThe average follow-up period was 4.8 years (range, 2.1–8.5 yr). Both clinical and radiologic results werefavorable. ROM of the hip joints improved in all patients.Pain disappeared in all five patients. Walking abilityimproved in 10 patients. The four bed-ridden patientscould all sit postoperatively. Of the eight sitters, onlyone did not improve; six became house-ambulators,and one became a community-ambulator. All six houseambulatorsbecame community-ambulators. The fivecommunity-ambulators retained their good functionalstatus after surgery.Radiographically, in the 15 subluxated hips, the meanCEA was 32° (range, 5°–50°), the AI was 19.0° (range, 5°–30°), and the NSA was 137° (range, 130°–160°); the CEAand AI were significantly improved compared with preoperativevalues (p < 0.005). For the 12 dislocated hips, theCEA was 21° (range, 0°–65°), the AI was 21° (range, 10°–J Formos Med Assoc 2001 • Vol 100 • No 4 251

C.T. Wu, S.C. Huang, and C.H. ChangFig. 1. A) Case 19: a 13-year-old boywith left hip subluxation with erosionof the femoral head. B) Varusderotational osteotomy and Degaosteotomy were performed. C) Six yearslater, remodeling of the acetabulumand femoral head is evident, and theboy felt no hip pain.A B CABC35°), and the NSA was 130° (range, 100°–152°). Thesechanges were also all statistically significant (p < 0.001).Complications developed in five patients. Case 4had nonunion at the varus osteotomy site, which resolvedafter replating and bone grafting. Her right hip,initially normal, progressively developed dislocation 2years later. Varus derotational osteotomy was performedto stabilize the hip. A similar situation occurred in Case11. Redislocation of the hip developed in two patients(two hips) and resubluxation in one (one hip).Redislocation of the hip in Case 6 (Fig. 3), whichhappened after removal of the spica, was treated byopen reduction, spica casting for 6 weeks, and anabduction brace for 3 months. Redislocation of theright hip in Case 22, which developed progressively3 months after surgery, was treated by closed reduction,Staheli slotted acetabular augmentation, spica castfor 6 weeks, and abduction brace for 3 months. Resubluxationof the hip in Case 12 was treated by VDO,Chiari osteotomy with shelf augmentation, and spicacast for 6 weeks. All of the patients still had residualsubluxation at the final follow-up.The Table summarizes the clinical characteristics,surgical procedures, and outcomes in all patients.DiscussionFig. 2. A) Case 20: an 8-year-old boy with bilateral hip subluxation.B) Bilateral hamstring release, open reduction, varus derotationalosteotomy, and Pemberton ostotomy were performed. C) Three yearslater, a good result is seen in both hips.252The natural course of untreated subluxated or dislocatedhips in CP patients often leads to pain, decreasein walking ability, severe limitation in sitting, andincreased difficulty in perineal care [4, 9, 10]. Theetiology of pain is believed to be excessive pressure onJ Formos Med Assoc 2001 • Vol 100 • No 4

Surgery for Hip Dislocation in Cerebral PalsyA B C DFig. 3. A) Case 6: an 8-year-oldgirl with left hip dislocation.B) Soft tissue release, openreduction, varus derotationalosteotomy, and Pembertonosteotomy were performed. C)Progressive hip subluxation isnoted 2 months after operation; asecond operation was performedwith open reduction, hip spica,and prolonged abduction brace.D) Eight years later, a satisfactoryresult was observed. The platewas then removed.the femoral head as well as the loss of articular cartilageand deformity of the head. Patients with painful dislocatedor subluxated hips have previously been shown tobenefit from surgical treatment [11, 12], and thisfinding is supported by the results of our series.The pathologic factors leading to hip deformityinclude spastic muscle imbalance, non-ambulation,coxa valga, femoral head anteversion, and acetabulardysplasia [1]. If the hip subluxation is left untreated,there is a 10% to 18% annual lateral migration of thefemoral head [13]. Bagg et al reported that, if leftuntreated, two-thirds of their CP patients remained hipsubluxated, and one-sixth of the hips became dislocated[14]. Rapid deterioration of the deformity wasnoted, especially when the CEA was less than 0°. Cookeet al reported that, in the radiographic evaluation of462 CP patients, AI was the most powerful single predictorof hip dislocation [15]. They suggested thatradiographic screening for CP hip dislocation shouldbe performed by measurement of the AI at 2 and 4 yearsof age.Deformity of the hip joint has been studied bycomputerized tomography (CT). Using three-dimensional(3-D) images, Abel et al found that acetabularroof development is the factor most strongly associatedwith the degree of hip subluxation [16]. They demonstratedthat the majority of CP hips, especially amongnon-ambulatory quadriparetic patients, weresubluxating in a posterosuperior direction in associationwith flexion and adduction contracture of thefemur. They recommended that acetabular reconstructionsdesigned to obtain anterior coverage (eg, Salteror double osteotomy) should not be employed.However, some authors found otherwise. Gugenheimet al reported that an anterior deficiency in the acetabulumin congenital and paralytic hip instability wasdemonstrated by transpelvic CT [17]. Kim and Wengerfound, using a 3-D CT technique, that the location ofacetabular deficiency in patients with neuromusculardisease was posterior (37%), anterior (29%),midsuperior (15%), and mixed (19%) (anterosuperior,posterosuperior, and global) [18]. They concludedthat the choice of pelvic osteotomy depended on thenature of the acetabular deficiency, which should beconfirmed by 3-D CT or arthrographic methods. Salterosteotomy did not cause any complication in any of ourfive patients. This procedure is contraindicated onlywhen the acetabular deficiency is in a posterosuperiordirection, because it was designed to obtain betteranterior coverage. As mentioned earlier, Pembertonosteotomy is being increasingly used in our hospital;although its technical demand is equivalent to that ofSalter osteotomy, more angular correction can beachieved, and k-wire fixation is not needed, whichmeans fewer pin-related problems.In this series, mild subluxation of the hip joints wastreated by combined soft tissue release and VDO. Softtissue release alone was not used because it leads torecurrence of dislocation or subluxation in manypatients, especially in quadriplegic patients [12, 19].Better results are obtained when corrective surgery isdone before the development of acetabular dysplasia.Sharrard et al reported that, of 49 patients withsubluxated hips, 12 remained subluxated after a softtissue procedure, and only 13 were normal. Moreover,three of four dislocated hips remained subluxated[12]. Samilson et al reported that 25% of patients whohad adductor release later experienced hip dislocation[5]. However, when the hip was already dislocatedprior to soft tissue release, they found the results wereconsistently unfavorable, as did Sherk et al [19].For our patients, severe hip instability was stabilizedby aggressive, combined procedures that included softtissue release, VDO, and pelvic osteotomy. Houkom etal found that hip dislocation in children younger than6 years old is best treated with combined soft tissueJ Formos Med Assoc 2001 • Vol 100 • No 4 253

C.T. Wu, S.C. Huang, and C.H. ChangTable. Clinical characteristics, surgical procedures, and outcomesSex Age Side Type Hip Walking Pain Ad Fle Ham OR VDO Pelvic Duration Complication Subsequent Walking Pain(yrs + status ability operation abilitymos)1 M 5+6 R, L Quad D, S Sit N B B N N B N 7+2 N N Sit N2 F 3+7 R Quad D Lie N B N N R R N 26+1 N Sit N3 F 4+10 R Quad S Sit N R R N N R Salter 6+7 N N House ambul N4 F 6+2 R Di D Sit N B L L N 5+4 Nonunion Osteosynthesis House, NR dislocation VDO (80.05) Ambul5 F 1+8 L Quad D Lie N N N N L N Salter 5+3 N N Sit N6 F 8+3 L Di D Sit N B B B L L Pemberton 8+6 Redislocation Open reduction Comm N(76.04) ambul7 M 3+5 R Quad S Lie N N N N R R Salter 5+2 N N Sit N8 F 9+3 R Quad S Sit N B N N N R Pemberton 5+1 N N House ambul N9 M 4+9 L Quad S Lie N B N B N L N 5+10 N N Sit N10 F 3+4 L Quad D Sit N N N N L L Salter 4+2 N N House ambul N11 F 9+3 L Di D Comm N N N N L L Triple 7+10 R dislocation Open, VDO, Comm Nambul triple (83.07) ambul12 M 7+5 L Quad D House N N N N L L Triple 4+1 Subluxation VDO, Chiari, Comm Nambul shelf (80.07) ambul13 F 7+1 R Quad D Sit N R N N R R Triple 4+1 N N House ambul N14 M 7+3 L Di S Comm N B B B N N Pemberton 4+2 N N Comm Nambul ambul15 M 7+6 R, L Di S, S Sit N B B B N B N 4+1 N N House ambul N16 F 9+1 R Hemi S Comm N R R N N R Dega 4+1 N N Comm Nambul ambul17 M 14+5 R Di S House Y R N N N R Dega 3+1 N N Comm Nambul ambul18 F 8+9 R Hemi D Comm N N N R R R Dega 3+10 N N Comm ambul Nambul19 M 13+10 L Hemi S House Y L N N N L Dega 4+7 N N Comm ambul Nambul20 M 8+6 R, L Di S, S House Y N N B B B Pemberton 3+10 N N Comm ambul Nambul21 F 6+10 R Hemi S Comm N R R B N R Salter 2+3 N N Comm ambul Nambul22 F 13+10 R, L Quad D, D House Y B B N B B Dega 2+1 R redislocation Closed reduction, Comm ambul Nambul Staheli (82.12)23 F 11+8 L Di S House Y L L N N L Triple 2+2 N N Comm ambul NambulAd = adductor release; Fle = flexor release; Ham = hamstring release; OR = open reduction;VDO = varus derotational osteotomy; M = male; R = right; L = left; Quad = quadriplegia;D = dislocation; S = subluxation; N = no; B = bilateral; F = female; ambul = ambulatory; Di = diplegia; Comm = community; Hemi = hemiplegia.254J Formos Med Assoc 2001 • Vol 100 • No 4

elease and bone reconstruction [20]. Based on thestudy of the anatomy of hip deformity in CP patients,Bleck advocated a combined approach consisting ofbilateral adductor release, obturator neurectomy, iliopsoasrelease, open reduction, VDO (with femoralshortening as necessary), and iliac osteotomy [11]. Hecautioned that the articular cartilage of the femoralhead must appear satisfactory at the time of capsulotomyin order to proceed with relocation of the femoralhead. For patients younger than 10 years old, he recommendeda Pemberton osteotomy; for older patients, aChiari osteotomy. Samilson et al also found the Chiariosteotomy to be beneficial for older patients withacetabular dysplasia [5], but Sherk et al warned thathip extension contracture or knee flexion contracturemust be corrected or the results could be compromised[19]. Hips with severe, globally insufficient acetabulummay be better treated with a shelf augmentation ora combined Chiari and shelf procedure because of thegreater flexibility in covering the femoral head [21].Song and Carroll suggested that the incidence ofresubluxation or redislocation is related to the preoperativelack of coverage of the femoral head, and theunstable hip with a lack of coverage of greater than70% needs a combined VDO and acetabular procedure[22]. The Staheli acetabular augmentation is notintended to be used as a prophylactic procedure, nor isit for the hip-at-risk or mildly subluxated hip in veryyoung patients [23]. Pelvic osteotomy must be selectedin accordance with the deformity and dysplasia of theacetabulum [18, 24].Because of asymmetric involvement or muscleimbalance, dislocation of the contralateral hip maydevelop, as was the case in two of our patients. Anotherinteresting finding of Carr and Gage was that unilateralsoft tissue release should be avoided due to the deleteriouseffect on the contralateral hip [9]. However, inour series, soft tissue release was performed when thejoint contracture became the major concern, so contralateralsoft tissue release was not routinely performed,and further investigation of its effect on the contralateralhip is needed. We believe that redislocation andresidual subluxation are due to inadequate correctionand existing dysplasia. Reviewing the possible reasonsfor postoperative complications in our series, we foundthat in Case 22, inadequate VDO and more severeacetabular dysplasia of the right hip was noted whencompared with the left side. A fluoroscopic examinationduring surgery would have enabled us to avoid thiscomplication. We think that the development of postoperativehip subluxation in one patient was mainlydue to inadequate postoperative protection, becausethe immediate postoperative radiographic evaluationwas satisfactory. In short, overcorrection or hypercontainmentmay be beneficial. However, there is stillSurgery for Hip Dislocation in Cerebral Palsycontroversy about the efficacy of prolonged bracing orcasting. Miller et al found a much lower incidence ofpostoperative fracture if patients were mobilized byphysical therapy immediately after surgery [25]. Inconclusion, when hip subluxation or dislocation isconfirmed, early adequate soft tissue release and combinedbone reconstruction procedures are necessaryto maintain hip stability, which helps to improve thefunctional status of CP patients.References1. Gamble JG, Rinsky LA, Bleck EE: Established hip dislocationsin children with cerebral palsy. Clin Orthop 1990;253:90–9.2. Pritcheff JW: The untreated unstable hip in severe cerebralpalsy. Clin Orthop 1983;173:169–72.3. Rang M, Douglas G, Bennet GC, et al: Seating forchildren with cerebral palsy. J Pediatr Orthop 1981;1:279–87.4. Cooperman DR, Bartucci E, Dietrick E, et al: Hip dislocationin spastic cerebral palsy: long-term consequences.J Pediatr Orthop 1987;7:268–76.5. Samilson RL, Tsou P, Aamoth G, et al: Dislocation andsubluxation of the hip in cerebral palsy: pathogenesis,natural history and management. J Bone Joint Surg Am1972;54:863–73.6. Hoffer MM, Stein GA, Koffman M, et al: Femoral varusderotationosteotomy in spastic cerebral palsy. J Bone JointSurg Am 1985;67:1229–35.7. Ko JY, Shih CH, Mubarak SJ, et al: Combined osteotomyand soft tissue release for spastic dislocated hip. J OrthopSurg ROC 1996;13:50–8.8. Mubarak SJ, Valencia FG, Wenger DR: One-stage correctionof the spastic dislocated hip: use of pericapsularacetabuloplasty to improve coverage. J Bone Joint Surg Am1992;74:1347–57.9. Carr C, Gage JR: The fate of the nonoperated hip incerebral palsy. J Pediatr Orthop 1987;7:262–7.10. Lonstein JE, Beck K: Hip dislocation and subluxation incerebral palsy. J Pediatr Orthop 1986;6:521–6.11. Bleck EE: The hip in cerebral palsy. Orthop Clin North Am1980;11:79–104.12. Sharrard WJ, Allen JM, Heaney SH: Surgical prophylaxisof subluxation and dislocation of the hip in cerebralpalsy. J Bone Joint Surg Br 1975;57:160–6.13. Onimus M, Allamel G, Manzone P, et al: Prevention ofhip dislocation in cerebral palsy by early psoasand adductors tenotomies. J Pediatr Orthop 1991;11:432–5.14. Bagg MR, Farber J, Miller F: Long-term follow-up of hipsubluxation in cerebral palsy patients. J Pediatr Orthop1993;13:32–6.15. Cooke PH, Cole WG, Carey RP: Dislocation of the hip incerebral palsy: natural history and predictability. J BoneJoint Surg Br 1989;71:441–6.J Formos Med Assoc 2001 • Vol 100 • No 4 255

C.T. Wu, S.C. Huang, and C.H. Chang16. Abel MF, Wenger DR, Mubarak SJ, et al: Quantitativeanalysis of hip dysplasia in cerebral palsy: a study ofradiographs and 3-D reformatted images. J Pediatr Orthop1994;14:283–9.17. Gugenheim JJ, Gerson LP, Sadler C, et al: Pathologicmorphology of the acetabulum in paralytic and congenitalhip instability. J Pediatr Orthop 1982;2:397–400.18. Kim HT, Wenger DR: Location of acetabular deficiencyand associated hip dislocation in neuromuscular hipdysplasia: three-dimensional computed tomographicanalysis. J Pediatr Orthop 1997;17:143–51.19. Sherk HH, Pasquariello PD, Doherty J: Hip dislocation incerebral palsy: selection for treatment. Dev Med ChildNeurol 1983;25:738–46.20. Houkom JA, Roach JW, Wenger DR, et al: Treatment ofacquired hip subluxation in cerebral palsy. J Pediatr Orthop1986;6:285–90.21. Roye DP Jr, Chorney GS, Deutsch LE, et al: Femoral varusand acetabular osteotomies in cerebral palsy. Orthopedics1990;13:1239–43.22. Song HR, Carroll NC: Femoral varus derotation osteotomywith or without acetabuloplasty for unstable hips incerebral palsy. J Pediatr Orthop 1998;18:62–8.23. Zuckerman JD, Staheli LT, McLaughlin JF: Acetabularaugmentation for progressive hip subluxation in cerebralpalsy. J Pediatr Orthop 1984;4:436–42.24. Gordon JE, Capelli AM, Strecker WB, et al: Pembertonpelvic osteotomy and varus rotational osteotomy in thetreatment of acetabular dysplasia in patients who have staticencephalopathy. J Bone Joint Surg Am 1996;78:1863–71.25. Miller F, Girardi H, Lipton G, et al: Reconstruction of thedysplastic spastic hip with peri-ilial pelvic and femoralosteotomy followed by immediate mobilization. J PediatrOrthop 1997;17:592–602.256J Formos Med Assoc 2001 • Vol 100 • No 4