The prognostic value of the head-shaft angle on hip displacement in children with cerebral palsy

BackgroundHip displacement is the second most common deformity in cerebral palsy (CP). The risk for hip displacement is related to the Gross Motor Function Classification System (GMFCS). Recently, the head-shaft angle (HSA) has been identified as a predictor for hip displacement and the aim of this study is to assess the predictive value of the HSA for hip displacement in CP.MethodsIn this retrospective cohort, we performed radiological measurements in 50 children on both hips. In children with GMFCS level II (30 hips), III (30 hips), IV (20 hips) and V (20 hips), we measured the HSA and migration percentage (MP) in three age intervals: age two years (T1), age four years (T2) and age seven years (T3).ResultsAt T1, the HSA was larger (more valgus) in hips that will displace than in hips that will not displace (174° vs. 166°; p = 0.001) and was also larger in higher GMFCS levels (IV–V vs. II–III) (172° vs. 165°; p < 0.001). At T1, GMFCS [odds ratio (OR) 14.7; p = 0.001] and HSA (OR 1.102; p = 0.043) were predictors for hip displacement at T3, but at T2, MP (OR 1.071; p = 0.010) was the only predictor for hip displacement at T3.ConclusionsThe HSA at two years is larger in hips that will displace and larger in children with higher GMFCS levels (IV–V). At age two years, GMFCS and HSA are valuable predictors for hip displacement, but at the age of four years, only MP should be used in the prediction of hip displacement.

Level of evidence

Prognostic study, level II.     

Primary surgery to prevent hip dislocation in children with cerebral palsy in Sweden: a minimum 5-year follow-up by the national surveillance program (CPUP)

Background and purpose — Children with cerebral palsy (CP) have an increased risk of hip dislocation. Outcome studies after surgery to prevent hip dislocation in children with CP are usually retrospective series from single tertiary referral centers. According to the national CP surveillance program in Sweden (CPUP), hip surgery should preferably be performed at an early age to prevent hip dislocation. Preventive operations are performed in 12 different Swedish hospitals. We compared the outcomes between soft tissue release and femoral osteotomy in children with CP treated in these hospitals.

Patients and methods — 186 children with CP underwent either adductor–iliopsoas tenotomy (APT) or femoral osteotomy (FO) as the primary, preventive surgery because of hip displacement. They were followed for a minimum of 5 years (mean 8 years) regarding revision surgery and hip migration. A good outcome was defined as the absence of revision surgery and a migration percentage (MP) < 50% at the latest follow-up. Logistic and Cox regression analysis were used to investigate the influence of age, sex, preoperative MP, Gross Motor Function Classification System (GMFCS) level, and CP subtype.

Results — APT was performed in 129 (69%) children. After 5 years, the reoperation rate was 43%, and 2 children (2%) had an MP > 50%. For the 57 children who underwent FO, the corresponding figures were 39% and 9%. Of the potential risk factors studied, the outcome was statistically significantly associated with preoperative MP only in children who underwent APT, but not in those who underwent FO. None of the other factors were significantly associated with the outcome in the 2 procedure groups.

Interpretation — Reoperation rates after preventive surgery are high and indicate the importance of continued postoperative follow-up. Age, sex, GMFCS level, and CP subtype did not influence the outcome significantly.     

Hip displacement in relation to age and gross motor function in children with cerebral palsy

Purpose

Hip dislocation in cerebral palsy (CP) is a serious complication. By radiographic screening and prophylactic surgery of children at risk most dislocations can be prevented. CPUP, the Swedish CP registry and follow-up program, includes annual radiographic examinations of children at Gross Motor Function Classification System (GMFCS) levels III–V. Data from CPUP were analysed to assess the risk of hip displacement in relation to GMFCS levels and age.

Methods

All children at GMFCS levels III–V (N = 353) whose first radiographic screening occurred before 3 years of age were followed between the ages 2–7 years. Migration percentages (MPs) were recorded annually (1,664 pelvic radiographs) and analysed using discrete time survival analysis.

Results

The risk of hip displacement between 2 years and 7 years of age was significantly (p < 0.05) higher for children at GMFCS level V during the entire study period. The risk was highest at 2–3 years of age and decreased significantly (p < 0.001) with each year of age (OR = 0.71, 95 % CI 0.60–0.83). The cumulative risk at age 7 years for those at GMFCS V for MP ≥ 40 % was 47 % (95 % CI 37–58). The corresponding risk at GMFCS IV was 24 % (16–34) and at GMFCS III 23 % (12–42).

Conclusions

Children at GMFCS V have a significantly higher risk of hip displacement compared with children at GMFCS III–IV. The risk is highest at 2–3 years of age. The results support a surveillance program including radiographic hip examinations as soon as the diagnosis of severe CP is suspected.     

To what extent can soft-tissue releases improve hip displacement in cerebral palsy?

Background and purpose — Hip displacement is frequent in nonambulatory children with cerebral palsy (CP) and treatment is controversial. This prospective study assesses the effectiveness of soft-tissue releases to treat hip subluxation, analyses prognostic factors for outcome, and identifies time to failure in hips with poor outcome.

Patients and methods — 37 children (16 girls) with hip subluxation were recruited from the population-based screening program for children with CP in Norway. They had consecutively undergone soft-tissue releases (bilateral tenotomies of adductors and iliopsoas) at a mean age of 5.0 (2.8–7.2) years. Functional classification was Gross Motor Function Classification System (GMFCS) level III in 9 children, level IV in 10, and level V in 18 children. The outcome was termed good if the patient had not undergone further hip surgery and if the migration percentage (MP) of the worst hip at the latest follow-up was <50%. The mean follow-up time was 7.3 (5.1–9.8) years.

Results — The outcome was good in all the ambulatory children and in 17 of 28 of the nonambulatory children. The only independent preoperative risk factor for poor outcome was MP ≥50%. The mean time to failure was 2.2 (1–5) years postoperatively and the reasons for failure were insufficient initial correction and later deterioration of displacement.

Interpretation — Bilateral soft-tissue release is recommended in both ambulatory and nonambulatory children with hip sub­luxation. The operation should be performed before the hip displacement reaches 50%.     

Hip Displacement in Cerebral Palsy: The Role of Surveillance

IntroductionHip displacement is common in cerebral palsy (CP) and is related to the severity of neurological and functional impairment. It is a silent, but progressive disease, and can result in significant morbidity and decreased quality of life, if left untreated. The pathophysiology of hip displacement in CP is a combination of hip flexor-adductor muscle spasticity, abductor muscle weakness, and delayed weight-bearing, resulting in proximal femoral deformities and progressive acetabular dysplasia. Due to a lack of symptoms in the early stages of hip displacement, the diagnosis is easily missed. Awareness of this condition and regular surveillance by clinical examination and serial radiographs of the hips are the key to early diagnosis and treatment.Hip surveillance programmesSeveral population-based studies from around the world have demonstrated that universal hip surveillance in children with CP allows early detection of hip displacement and appropriate early intervention, with a resultant decrease in painful dislocations. Global hip surveillance models are based upon the patients’ age, functional level determined by the Gross Motor Function Classification system (GMFCS), gait classification, standardized clinical exam, and radiographic indices such as the migration percentage (MP), as critical indicators of progressive hip displacement.ConclusionDespite 25 years of evidence showing the efficacy of established hip surveillance programmes, there is poor awareness among healthcare professionals in India about the importance of regular hip surveillance in children with CP. There is a need for professional organizations to develop evidence-based guidelines for hip surveillance which are relevant to the Indian context.     

Deformities of proximal femur in spastic hip displacement: A reconstructed three-dimensional computed tomography model approach

Background/PurposeSpastic hip displacement is a common musculoskeletal problem in cerebral palsy (CP), leading to further complications in daily life. Deformities of the proximal femur were regarded as a factor in hip displacement, and therefore, femoral osteotomy is often recommended. This study aims to identify the relationship between hip displacement and femoral deformities.MethodsWe retrospectively collected preoperative radiography and three-dimensional computed tomography (3D-CT) images from 19 nonambulatory CP children with unilateral hip displacement (average age: 8.4 years; range: 4.4–13.6). The 3D image of femur was reconstructed for measuring the femur anteversion angle (FAA) and true femoral neck-shaft angle (NSA). The association among migration percentage (MP), acetabular index (AI), FAA, and NSA between nondisplaced and displaced hips was analyzed by paired t test and its correlations were identified.ResultsThe FAA and AI are significantly greater in displaced hips (42.7° vs. 36.3° and 32.8° vs. 22.7°, respectively, p < 0.001). However, the NSA is similar between displaced and nondisplaced hips. The AI and FAA have significantly positive correlations with MP between nondisplaced hips and displaced hips (0.69 and 0.57, respectively).ConclusionUsing reconstructed 3D-CT images we can directly measure and prove these femoral deformities. We found that AI has a positive correlation with MP (0.69), which is consistent with the results of previous studies. The displaced side has greater femur anteversion (42.7° vs. 36.3°), and coxa valga is common in these nonambulatory patients, irrespective of whether or not these patients underwent hip displacement. In addition, the severity of AI and anteversion angle will be affected by the MP.     

Development of the hip joints in unoperated children with cerebral palsy: A radiographic study of 76 patients

Background?The aims of the present study were to assess the development of hip dysplasia in children with bilateral spastic cerebral palsy and to evaluate the factors that influence the progression.

Patients and methods?76 children, 42 with spastic quadriplegia and 34 with diplegia, were included in the study. Their mean age at the first radiographic examination was 3.5 (1–11) years. The patients were followed up until operative treatment (54 subjects) or until the most recent radiograph in those who did not undergo hip surgery. The mean length of follow-up was 4.8 (1–13) years. On the initial and most recent radiographs, the migration percentage (MP) was measured, which is the percentage of the femoral head lateral to the acetabular rim.

Results?The mean MP of the side with the largest displacement was 25% (-18–66) at the initial radiographic examination and 51% (9–100) at the last follow-up. The mean increase in MP was 7% (-2–33) per year. Linear multiple regression revealed that gait function and age were the most important variables that influenced the rate of MP progression. Children who could not walk had significantly greater MP progression per year (12%) than those who walked with or without support (2%). In the quadriplegics, the maximal yearly increase in MP was 13% under 5 years of age and 7% in older children. This difference was statistically significant, whereas no significant difference in relation to patient age was seen in the diplegics.

Interpretation?There is a pronounced trend towards displacement of the hips in quadriplegic CP patients who are under 5 years of age and cannot walk. Because hip dislocation may lead to severe problems, close follow-up is important in finding the appropriate time for hip surgery in order to avoid progression towards dislocation. The risk of severe hip dysplasia is considerably less in spastic diplegia.??     

Unilateral varus osteotomy of the proximal femur in children with cerebral palsy: a five-year follow-up of the development of both hips

Background  

Varus osteotomy of the proximal femur (VOPF) is one treatment option to prevent hip dislocation in children with cerebral palsy (CP). It is questioned whether the osteotomy should be performed in the displaced hip only, or if it should be performed bilaterally to prevent later displacement of the contralateral hip. CPUP is a register and healthcare programme for children with CP that was initiated in 1994 in southern Sweden. In the programme, range-of-motion and radiographic examination of the hips is performed regularly. These data have been analysed preoperatively and for 5 years postoperatively in children treated with unilateral VOPF.     

Recurrent hip instability after hip reconstruction in cerebral palsy children with spastic hip disease

BackgroundMigration percentage (MP) is widely used to evaluate hip stability in children with spastic cerebral palsy (CP). Orthopedic surgeons need more objective information to make a proper hip reconstruction surgical plan and predict the outcome.MethodsMedical records and plain radiographs of children with CP who underwent the hip reconstruction procedure for dysplasia were reviewed retrospectively.ResultsIn total, 253 operated hips (140 patients; 11.7 ± 3.3 years old) were included in this study. MP at pre-operative (T_pre) was 35.3 ± 22.5%; at immediate follow-up (T_post) was 5.9 ± 9.5%; at last follow-up (T_final) was 9.8 ± 10.8% (4.5 ± 2.3 years post-operative at age 16.3 ± 2.8 years). In hips with Melbourne Cerebral Palsy Hip Classification Scale (MCPHCS) grade 3 (n = 78), around 30–45% had an unsatisfactory outcome at T_post and T_final. However, hips categorized as other grades showed only 2.1–9.1% of unsatisfactory outcome. In less affected hips (pre-operative MP<30%, n = 122), 109 hips (89.3%) had varus derotation osteotomy only, the other 13 hips (10.7%) were combined with a pelvic osteotomy. In more severely affected hips (pre-operative MP ≥ 30%, n = 131), 26 hips (19.8%) had varus derotation osteotomy only, the other 105 hips (80.2%) were combined with a pelvic osteotomy.ConclusionsHips with pre-operative MP between 15 and 29% (MCPHCS grades 3) can be a higher risk group of recurrent hip instability after hip reconstruction surgery. Multiple indications beyond MP should be considered when indicating pelvic osteotomy or hip muscle release as combined procedures with varus femoral osteotomy for hip reconstruction in this milder group to achieve a consistent long-term satisfactory outcome.     

Severe hip displacement reduces health-related quality of life in children with cerebral palsy

Background and purpose — Hip displacement is common in children with severe cerebral palsy (CP) and can cause problems such as pain, contractures, and nursing difficulties. Caregiver priorities and child health index of life with disabilities (CPCHILD) is a recently developed measure of health-related quality of life (HRQL) in children with severe CP. The associations between CPCHILD scores and hip displacement have not been investigated. We explored the effect of hip displacement on HRQL.

Patients and methods — 67 children were recruited from the population-based Norwegian CP register. Mean age was 9 (7–12) years. There were 40 boys. Gross motor function classification system (GMFCS) distribution was 12 level III, 17 level IV, and 38 level V. Hip displacement was assessed by radiographic migration percentage (MP). The criterion for hip displacement was MP of the worst hip of ≥40%. Primary caregivers responded to 5 of the 6 domains of the CPCHILD questionnaire.

Results — Hip displacement was found in 18 children and it was significantly associated with lower scores on the CPCHILD domains 3 (Comfort and Emotions) and 5 (Health), but not with domains 1 (Activities of Daily Living/Personal Care), 2 (Positioning, Transfer, and Mobility), and 6 (Overall Quality of Life). GMFCS level V was a significant predictor of low scores in all the domains.

Interpretation — For the assessment of HRQL in children with severe CP and hip problems, we propose a modified and simplified version of the CPCHILD consisting of 14 of 37 questions. This would reduce the responders’ burden and probably increase the response rate in clinical studies without losing important information.     

Utility of combined hip abduction angle for hip surveillance in children with cerebral palsy

Background:

Spontaneous hip lateralization complicates the management of non-ambulatory children with cerebral palsy (CP). It can be diagnosed early using radiographs, but it involves standardization of positioning and exposure to radiation. Hence, the aim of this study was to assess the utility of Combined hip abduction angle (CHAA) in the clinical setting to identify those children with CP who were at greater risk to develop spontaneous progressive hip lateralization.

Materials and Methods:

One hundred and three children (206 hips) with CP formed our study population. There were 48 boys and 55 girls aged 2–11 years (mean 5.03 years). 61 children were Gross Motor Function Classification System (GMFCS) level 5, while 42 were GMFCS level 4. Clinical measurements of CHAA were statistically correlated with radiographic measurements of Reimer''s migration percentage (MP) for bivariate associations using χ² and t tests.

Results:

CHAA is evaluated against MP which is considered as a reliable measure of hip subluxation. Thus, for CHAA, sensitivity was 74.07% and specificity was 67.35%. False-positive rate was 32.65% and false-negative rate was 25.93%.

Conclusions:

Our study shows that correlation exists between CHAA and MP, which has been proved to be useful for hip screening in CP children at risk of hip dislocation. CHAA is an easy, rapid, cost-effective clinical test which can be performed by paraclinical health practitioners (physiotherapists) and orthopedic surgeons.     

Radiographic threshold values for hip screening in cerebral palsy

Purpose To analyse the consequences of using different radiographic measurements and different threshold values for hip screening in children with cerebral palsy (CP). Methods In a total sample of children with CP a standardised radiological follow-up of the hips was carried out as a part of a hip prevention programme. Acetabular index (AI) and migration percentage (MP) were measured on all radiographs. In this study, 1,067 radiographs of 272 children born 1992–1998 were analysed. Results Lateral displacement of the femoral head was common without acetabular dysplasia, and acetabular dysplasia occurred at a later stage than femoral head lateralisation. Hip dysplasia without lateral displacement of the femoral head was rare. In 16 of the 56 hips (29%) with AI ≥ 27° and in 23 of the 71 (32%) hips with MP ≥ 33% the values decreased below the threshold value without operative treatment. In hips with AI ≥ 30° only 2 of 31 hips (6%) and in hips with MP ≥ 40% only 5 of 44 hips (11%) decreased below the threshold values without operative treatment. Conclusions Radiographic follow-up with only measurement of the MP seems sufficient in screening for dislocation in children with CP. MP ≥ 33% is recommended as threshold for reaction or intensified observation. In children with MP ≥ 40%, the lateral displacement increased over time in most hips, thus indicating the need for operative intervention. In children with MP 33–40%, treatment should be based on other clinical signs and the progression of MP over time.     

Hip surveillance and management of the displaced hip in cerebral palsy

Introduction

This article provides an overview of the management of a displaced hip in children with cerebral palsy and considers surveillance programmes, principles of surgical reconstruction and options for the salvage of an unreconstructable hip in these children.

Conclusion

Hip dislocation in CP is potentially preventable if children are included from an early age in a surveillance programme that includes repeat radiographic and clinical examinations, and preventive treatment for hips that are displacing. A surveillance programme should be based on the child’s age, GMFCS level and migration percentage (MP), and surgical prevention may be considered in children with a MP exceeding 33 %.     

3D打印技术辅助髋臼成形术治疗脑瘫儿童髋关节脱位

目的:探讨通过3D打印技术明确髋臼发育不良类型选择最合适的髋臼成形术治疗脑瘫儿童髋关节脱位的适应证和临床疗效。方法:自2019年7月至2019年12月,采用3D打印技术辅助髋臼成形术治疗7例脑瘫儿童髋关节脱位,其中男3例,女4例;年龄3~8岁;左侧3例,右侧2例,双侧2例;2例髋关节半脱位,5例髋关节脱位。患儿术前均行骨盆-双股骨全长CT扫描。通过3D打印重建技术,判断髋臼发育不良类型:前侧2髋,前外2髋,外上1髋,后侧2髋,后外1髋,无发育不良1髋(未做髋臼成形术)。对8髋分别进行Pemberton,Dega和San Diego手术模拟,寻找最合适的手术方式并手术。比较术前和末次随访外移比例(migration percentage,MP),髋臼指数(acetabular index,AI),中心边缘角(center-edge angle,CEA),Shenton线和粗大运动功能分级(gross motor function classification system,GMFCS)的变化,并记录其并发症情况。结果:术后患者伤口愈合良好,无并发症发生。7例患者获随访,时间18~24个月。8髋Ⅰ期行软组织松解+股骨近端内翻去旋转短缩截骨+髋关节复位+髋臼成形术;1髋Ⅰ期行软组织松解+股骨近端内翻去旋转短缩截骨+髋关节复位术。MP由术前的58%~100%降至末次随访时的0~17.9%。AI由术前的25.0°~47.6°降至末次随访时的11.1°~25.3°。CEA由术前的0°改善至末次随访时的21.1°~48.5°。Shenton''线均由中断变为连续。其中5例GMFCS分级下降1级,2例无变化。结论:脑瘫儿童髋关节脱位中髋臼发育不良的类型多样,髋臼成形术适用范围也有差异,借助3D打印技术计算机模拟手术可选择最合适的手术方式并判断治疗效果,对脑瘫儿童髋关节脱位做到个体化、精准化治疗。     

Characteristics of children with hip displacement in cerebral palsy

Background  

Hip dislocation in children with cerebral palsy (CP) is a common and severe problem. The dislocation can be avoided, by screening and preventive treatment of children with hips at risk. The aim of this study was to analyse the characteristics of children with CP who develop hip displacement, in order to optimise a hip surveillance programme.     

A balanced approach for stable hips in children with cerebral palsy: a combination of moderate VDRO and pelvic osteotomy

Background

Hip reconstructive surgery in cerebral palsy (CP) patients necessitates either femoral varus derotational osteotomy (VDRO) or pelvic osteotomy, or both. The purpose of this study is to review the results of a moderate varisation [planned neck shaft angle (NSA) of 130°] in combination with pelvic osteotomy for a consecutive series of patients.

Methods

Patients with CP who had been treated at our institution for hip dysplasia, subluxation or dislocation with VDRO in combination with pelvic osteotomy between 2005 and 2010 were reviewed.

Results

Forty patients with a mean follow-up of 5.4 years were included. The mean age at the time of operation was 8.9 years. The majority were non-ambulant children [GMFCS I–III: n = 11 (27.5 %); GMFCS IV–V: n = 29 (72.5 %)]. In total, 57 hips were treated with both femoral and pelvic osteotomy. The mean pre-operative NSA angle of 152.3° was reduced to 132.6° post-operatively. Additional adductor tenotomy was performed in nine hips (16 %) at initial operation. Reimers’ migration percentage (MP) was improved from 63.6 % pre-operatively to 2.7 % post-operatively and showed a mean of 9.7 % at the final review. The results were good in 96.5 % (n = 55) with centred, stable hips (MP <33 %), fair in one with a subluxated hip (MP 42 %) and poor in one requiring revision pelvic osteotomy for ventral instability.

Conclusions

This approach maintains good hip abduction and reduces soft-tissue surgery. Moderate varisation in VDRO in combination with pelvic osteotomy leads to good mid-term results with stable, pain-free hips, even in patients with severe spastic quadriplegia.

     

The unstable hip in children with cerebral palsy: does an acetabuloplasty add midterm stability?

PurposeThis study addresses whether an additional pelvic procedure is superior to a varus derotation osteotomy femur (VDRO) alone in unstable hips in children with cerebral palsy (CP).MethodsAll patients had unstable hips utilising the Melbourne Cerebral Palsy Hip Classification System (MCPHCS). We compared one group that underwent VDRO alone with one that had a combination of VDRO and Dega osteotomy (VDRO+). Measurements were taken before surgery, postoperatively, two years after surgery and at latest follow-up. Generalised estimating equations were used to account for known and unknown correlations between hips from bilateral cases.ResultsIn total, 74 hips in 57 children fulfilled the inclusion criteria. There was no outcome difference between Gross Motor Function Classification System levels III, IV and V. Age at time of operation ranged from three to 16 years (mean 9.8 years). Mean follow-up was 49.1 months. In the VDRO group (28 hips) migration percentage (MP) changed from 61% preoperative to a final value of 35.7%. In the VDRO+ group (46 hips) the MP changed from 64.4% to 19.3%. At final follow-up 15 hips (54%) were stable in the VDRO group, 37 hips (83%) in the VDRO+ group. The odds ratio (OR) of hip stability at final follow-up was 3.5-times higher in the VDRO+ group versus the VDRO group (OR = 3.9; 95% confidence interval = 1.5 to 9.7; p = 0.004).ConclusionReconstruction of unstable hips via VDRO + Dega in children with CP provides a higher likelihood of long-term stability than an isolated VDRO.Level of EvidenceLevel III, retrospective comparative study     

Adverse reaction to metal debris after Birmingham hip resurfacing arthroplasty

Background and purpose — Concern has emerged about local soft-tissue reactions after hip resurfacing arthroplasty (HRA). The Birmingham Hip Resurfacing (BHR) was the most commonly used HRA device at our institution. We assessed the prevalence and risk factors for adverse reaction to metal debris (ARMD) with this device.

Patients and methods — From 2003 to 2011, BHR was the most commonly used HRA device at our institution, with 249 implantations. We included 32 patients (24 of them men) who were operated with a BHR HRA during the period April 2004 to March 2007 (42 hips; 31 in men). The mean age of the patients was 59 (26–77) years. These patients underwent magnetic resonance imaging (MRI), serum metal ion measurements, the Oxford hip score questionnaire, and physical examination. The prevalence of ARMD was recorded, and risk factors for ARMD were assessed using logistic regression models. The mean follow-up time was 6.7 (2.4–8.8) years.

Results — 6 patients had a definite ARMD (involving 9 of the 42 hips). 8 other patients (8 hips) had a probable ARMD. Thus, there was definite or probable ARMD in 17 of the 42 hips. 4 of 42 hips were revised for ARMD. Gender, bilateral metal-on-metal hip replacement and head size were not factors associated with ARMD.

Interpretation — We found that HRA with the Birmingham Hip Resurfacing may be more dangerous than previously believed. We advise systematic follow-up of these patients using metal ion levels, MRI/ultrasound, and patient-reported outcome measures.     

Hip displacement in cerebral palsy

BACKGROUND: Hip displacement is considered to be common in children with cerebral palsy but the reported incidence and the proposed risk factors vary widely. Knowledge regarding its overall incidence and associated risk factors can facilitate treatment of these children. METHODS: An inception cohort was generated from the Victorian Cerebral Palsy Register for the birth years 1990 through 1992, inclusive, and multiple data sources pertaining to the cohort were reviewed during 2004. Gross motor function was assessed for each child and was graded according to the Gross Motor Function Classification System (GMFCS), which is a valid, reliable, five-level ordinal grading system. Hip displacement, defined as a migration percentage of >30%, was measured on an anteroposterior radiograph of the pelvis with use of a reliable technique. RESULTS: A full data set was obtained for 323 (86%) of 374 children in the Register for the birth years 1990 through 1992. The mean duration of follow-up was eleven years and eight months. The incidence of hip displacement for the entire birth cohort was 35%, and it showed a linear relationship with the level of gross motor function. The incidence of hip displacement was 0% for children with GMFCS level I and 90% for those with GMFCS level V. Compared with children with GMFCS level II, those with levels III, IV, and V had significantly higher relative risks of hip displacement (2.7, 4.6, and 5.9, respectively). CONCLUSIONS: Hip displacement is common in children with cerebral palsy, with an overall incidence of 35% found in this study. The risk of hip displacement is directly related to gross motor function as graded with the Gross Motor Function Classification System. This information may be important when assessing the risk of hip displacement for an individual child who has cerebral palsy, for counseling parents, and in the design of screening programs and resource allocation.     

Results and complications of percutaneous pelvic osteotomy and intertrochanteric varus shortening osteotomy in 54 consecutively operated GMFCS level IV and V cerebral palsy patients

Purpose

This retrospective study evaluated mid-to-long-term outcome of a minimally invasive percutaneous pelvic osteotomy (PPO) approach combined with varus derotational shortening osteotomy (VDRSO) and soft tissue release in children with severe CP.

Methods

A retrospective review was performed of all patients presenting with a diagnosis of CP with hip subluxation or dislocation treated surgically by simultaneous soft tissue release, VDRSO, and PPO between 2002 and 2015. Eligible patients included those with a diagnosis of spastic quadriplegia or CP GMFCS level IV or V with unilateral or bilateral hip subluxation or dislocation and surgical treatment of the deformity by simultaneous soft tissue release, VDRSO and PPO. All anterior–posterior (AP) radiographs of the pelvis were reviewed and Reimers migration percentage (MP) and acetabular angle (AA) were measured.

Results

In total, 54 children and adolescents (34 boys, 20 girls) with CP GMFCS level IV and V were treated during study period: 38 (70.4%) classified GMFCS level IV and 16 (29.6%) classified GMFCS level V. A total of 64 consecutive hips underwent simultaneous PPO associated with VDRSO. Overall, at the time of chart and radiograph review, mean age was 9.1 ± 3.3 years (range 4–16.5) and mean follow-up was 43.9 ± 19.5 months (range 3–72). Mean migration percentage improved from 66.8 ± 19.8% (range 33–100) preoperatively to 8.1 ± 16.5% (range 0–70) at last follow-up. Mean acetabular angle improved from 32.7° ± 7.1° (range 20–50) preoperatively to 14° ± 6.7° (range 0–27) at last follow-up. Only one case of bone graft dislodgment was observed. We did not observe any cases of avascular necrosis of the femoral head. All operated hips were pain free at the time of last follow-up.

Conclusion

PPO through a less invasive surgical approach offers a valuable alternative to standard techniques as it gives similar outcome but with less muscle stripping and less time in surgery.

Level of evidence

III.