Preoperative Migration Percentage Research Articles

Treatment of Hip Displacement in Children With Cerebral Palsy: A 5-year Comparison of Proximal Femoral Osteotomy and Combined Femoral-Pelvic Osteotomy in 163 Children.

This study compared the 5-year outcomes of isolated proximal femoral varus osteotomy (FO) and combined proximal femoral varus and pelvic osteotomy (FPO) for the treatment of hip displacement in children with cerebral palsy (CP) in Sweden, focusing on the number of reoperations and residual hip displacement. The study included 163 children with a 5-year follow-up after FO or FPO in the national Swedish CP surveillance program, CPUP. Descriptive statistics and univariate and multivariate Cox regression analyses were used to identify whether the age at surgery, sex, Gross Motor Function Classification System level, CP dominant symptom, hip migration percentage (MP), type of surgery (unilateral/bilateral), and history of soft tissue hip surgery were related to the 5-year outcomes after surgery. Failure after hip surgery was defined as a skeletal reoperation involving the hip and/or MP >50%. During the period 2001 to 2017, 163 children (65 girls) underwent 246 femoral and/or pelvic osteotomies (154 FO, 47 bilaterally; 92 FPO, 16 bilaterally) and had a 5-year follow-up; 95 and 74 children had ≥1 FO or FPO as the primary skeletal surgery, respectively. The mean preoperative MP (51%±18% for FO and 59%±17% for FPO, P =0.001) and age at surgery (6.2±2.5 years for FO and 7.3±2.8 years for FPO, P =0.014) differed between procedures. At the 5-year follow-up, 5 hips (5%) had reoperations and 5 hips (5%) had radiological failure among the 92 FPOs, and 33 (21%) had reoperations and 14 (9%) radiological failure among the 154 FOs. The difference in outcome failure rate was significant ( P <0.001). Multivariate Cox regression analysis showed a lower risk for failure with FPO [hazard ratio (HR)=0.32, 95% CI: 0.15-0.68] compared with FO. A higher preoperative MP increased the risk for outcome failure (HR=1.21, 95% CI: 1.15-1.36 for each 5% increment). FPO had a higher mean preoperative MP but a lower 5-year outcome failure rate compared with FO. A higher preoperative MP was associated with an increased risk of failure. Level II-prospective comparative study.

Timely Surgical Intervention Leads to Better Sustained Coverage after Reconstructive Hip Surgery in Patients with Cerebral Palsy.

In up to 45-90% of non-ambulatory patients with cerebral palsy (CP), progressive hip migration can be observed. The goal of this study was to determine whether the implementation of a national hip surveillance guideline affected the outcome of hip reconstructions. We reviewed 48 primary hip reconstructions at a median follow-up of 4.4 years. Surgical outcome was evaluated based on complication rates and radiographic evaluation postoperatively and at follow-up. Radiographic measurements included the migration percentage (MP), head-shaft angle and acetabular index. The impact of preoperative MP, postoperative MP, tone management, Gross Motor Function Classification System (GMFCS) classification and age on MP at follow-up were examined using a mixed model analysis. A decrease in preoperative MP was noted, from a median of 75.0% (2014) to 39.0% (2020). Lower preoperative MP showed a significant correlation to lower MP postoperatively (p = 0.012). Postoperative MP was a significant independent predictor of a lower MP at follow-up (p = 0.002). This study shows an improvement in the timing of hip reconstruction in patients with CP after implementation of the hip surveillance guideline. A reduction in preoperative MP resulted in improved postoperative outcomes. A lower postoperative MP was the most important predictor for sustained containment of the hip.

Outcome Prediction Model Following Proximal Femoral Osteotomy in Legg-Calvé-Perthes Disease Using Machine Learning Algorithms.

The purpose of the current study was (1) to analyze various factors that may be associated with the outcomes of Legg-Calvé-Perthes disease (LCPD), and (2) to develop and internally validate machine learning algorithms capable of providing patient-specific predictions of which patients with LCPD will achieve relevant improvement in radiologic outcomes after proximal femoral varus osteotomy (PFVO). We examined several variables, previously identified as factors, that may influence the outcome of LCPD and developed a machine learning algorithm based on them. In this retrospective study, we analyzed patients aged older than 6 years at the time of LCPD diagnosis who underwent PFVO at our institution between 1979 and 2015. Univariate and multivariate logistic regression analyses were used to examine the effects of variables on the sphericity of the femoral head at skeletal maturity, including age at onset, sex, stage at operation, extent of epiphyseal involvement and collapse, presence of specific epiphyseal, metaphyseal, and acetabular changes, and postoperative neck shaft angle (NSA). Recursive feature selection was used to identify the combination of variables from an initial pool of 13 features that optimized the model performance. Five machine learning algorithms [extreme gradient boosting (XGBoost), multilayer perception, support vector machine, elastic-net penalized logistic regression, and random forest) were trained using 5-fold cross-validation 3 times and applied to an independent testing set of patients. Ninety patients with LCPD who underwent PFVO were included in this study. The mean age at diagnosis was 7.93 (range, 6.0 to 12.33) years. The average follow-up period was 10.11 (range, 5.25 to 22.92) years. A combination of 8 variables, optimized algorithm performance, and specific cutoffs were found to decrease the likelihood of achieving the 1 or 2 Stulberg classification: age at onset ≤ 8.06, lateral classification ≤ B, 12.40 < preoperative migration percentage (MP) ≤ 22.85, Catterall classification ≤ 2, 117.4 < postoperative NSA ≤ 122.90, -10.8 < postoperative MP ≤ 6.5, 139.65 < preoperative NSA ≤ 144.67, and operation at stage 1. The XGBoost model demonstrated the best performance (F1 score: 0.78; area under the curve: 0.84). The XGBoost machine learning algorithm achieved the best performance in predicting the postoperative radiologic outcomes in patients with LCPD who underwent PFVO. In our population, age at onset ≤ 8.06, lateral classification ≤ B, 12.40 < preoperative MP ≤ 22.85, Catterall classification ≤ 2, 117.4 < postoperative NSA ≤ 122.90, -10.8 < postoperative MP ≤ 6.5, 139.65 < preoperative NSA ≤ 144.67, and operation at an early stage had the likelihood of achieving the spherical femoral head for the patients with LCPD that underwent PFVO. After external validation, the online application of this model may enhance shared decision-making. Level III-retrospective cohort study.

The Effect of Selective Dorsal Rhizotomy on Hip Displacement in Children With Cerebral Palsy: A Long-term Follow-up Study.

Hip displacement is common in children with cerebral palsy (CP). Spasticity in the hip adductor muscles, hip flexors, and medial hamstrings has been identified as a possible cause of progressive hip displacement. Selective dorsal rhizotomy (SDR) aims to reduce lower extremity spasticity in children with CP. Here, we investigate the influence of SDR on hip displacement in children with CP at long-term follow-up, a minimum of 5 years post-SDR. A retrospective review of children undergoing SDR at a Canadian pediatric hospital was completed. Migration percentage (MP) was measured on pelvis radiographs taken in the 6 months before SDR and minimum 5 years post-SDR or before hip surgery. The number of hips with displacement, defined as MP >30%, and the number of children with at least 1 hip displaced were determined. A linear mixed-effects model was used to assess potential risk factors for poor outcome post-SDR, defined as having MP >40% or surgical intervention for hip displacement. Ninety children [50 males, 40 females, Gross Motor Function Classification System (GMFCS) levels I to V: 1/13/24/43/9] with a mean follow-up of 8.5 years (SD 5.1) were included. The mean age at SDR was 4.9 years (SD 1.5); more than half of children (52%) had hip displacement at the time of SDR. Post-SDR, MP exceeded 30% in 0 (0%) of children at GMFCS level I, 1 (8%) at II, 11 (46%) at III, 31 (72%) at IV, and 7 (78%) at V. A poor outcome was associated with preoperative MP, age, and GMFCS level. The incidence of hip displacement post-SDR was consistent with population-based studies when evaluated by GMFCS. Our findings suggest that SDR has neither a positive nor negative effect on hip displacement when assessed at least 5 years postintervention. Level IV.

Does intrathecal baclofen therapy decrease the progression of hip displacement in young patients with cerebral palsy?

To evaluate the effects of intrathecal baclofen pump (ITBP) therapy on hip dysplasia in young patients with cerebral palsy (CP). This was a retrospective cohort series of prospectively collected data. Inclusion criteria were all patients with CP in Gross Motor Function Classification System (GMFCS) levels IV or V who underwent ITBP placement under 8 years old with at least 5 years of follow-up. Thirty-four patients were matched to a control group of 71 patients based on GMFCS level, motor type, medical comorbidities, worst hip migration percentage at ITBP placement, age, and Modified Ashworth scale scores. Patients were followed for at least 5 years or until they had hip reconstructive surgery. The primary outcome was the development of hip displacement as measured by the migration percentage at the latest follow-up or the preoperative migration percentage before hip reconstruction. The migration percentage at last follow-up was not statistically different between groups (ITBP: 36.2%, non-ITBP: 44.4%, p=0.14). The rates of future preventative, reconstructive, and recurrent hip surgery were not different between groups. The use of ITBP as an early treatment of spasticity did not alter the natural history of progressive hip displacement in non-ambulatory patients with CP and hip displacement is likely multifactorial, not solely due to spasticity.

Fate of hips complicated by avascular necrosis of the femoral head following reconstructive surgery in nonambulatory patients with cerebral palsy

The purpose of this study was to evaluate the influence of avascular necrosis of the femoral head (AVN) following hip reconstructions on the future hip development of cerebral palsy (CP) patients. A retrospective study of 394 hips in 205 nonambulatory patients with spastic CP who underwent reconstructive hip surgery was performed. The mean age at surgery was 7.3 ± 2.4 years. The mean follow-up duration was 5.6 ± 2.7 years, and the mean age at the latest follow-up was 12.8 ± 3.4 years. AVN was classified in terms of its severity and location. Femoral head remodelling was assessed by the spherical index and the Mose circle. An unsatisfactory radiological outcome was defined as having a migration percentage of more than 30% at the final follow-up. AVN was observed in 169 (42.9%) hips. Older age at the time of surgery, higher preoperative migration percentage, and open reduction procedures were predictors for the development of AVN. Hips with AVN confined to the lateral epiphysis, and AVN involving the entire epiphysis with preserved height experienced successful remodelling. 27 (65.9%) of the 41 hips with unsatisfactory outcomes experienced AVN. Younger age, higher postoperative migration percentage, and occurrence of AVN were related to unsatisfactory outcomes. The highest incidence of failed remodelling and unsatisfactory outcomes were observed in hips with entire epiphyseal involvement and more than 50% loss of its height. AVN following hip reconstructions is not necessarily associated with poor hip development, however, depending on the severity and location, it is a prognostic factor for unsatisfactory radiological outcomes.

Failure of Hip Reconstruction in Children With Cerebral Palsy: What Are the Risk Factors?

The rates and risk factors contributing to failure after hip reconstruction among patients with cerebral palsy (CP) are not well established. In analyzing a large cohort of children with CP who underwent hip reconstruction, the objectives of this study are to establish (1) the failure rates and (2) associated risk factors. This retrospective study included chart and radiographic review of patients between the ages of 1 to 18, with a diagnosis of CP, who underwent a hip reconstructive procedure at a single children's hospital over a 9-year period (2010 to 2018). Patients without at least 2 years of follow-up were excluded. Age at time of surgery, sex, Gross Motor Function Classification System (GMFCS), procedure(s) performed, preoperative migration percentage (MP), neck-shaft angle, and acetabular index (AI) were recorded. Failure was defined as need for revision surgery or a MP >50% on follow-up radiographs. Logistic regression and multiple-variable regression-type models were used to test for significance of risk factors. Of the 291 hips in 179 patients (102 males, 77 females) that met inclusion criteria, 38 hips (13%) failed. Significant differences in the failure group were seen in age at time of surgery (6.2±3.2 vs. 8.1±3.2; P<0.001), preoperative MP (62.3±28.7 vs. 39.9±24.1%; P<0.001) and preoperative neck-shaft angle (164.9±8.2 vs. 157.3±15.6 degrees; P<0.001). Age below 6 at time of surgery significantly increased failure rate (26% vs. 6.3%, P<0.001) as did preoperative MP >70% (28.9% vs. 9.9%, P<0.001). Receiving an acetabular osteotomy was protective against failure (9.1% vs. 16.9%, P=0.048), particularly in patients with a preoperative AI >25° (odds ratio=0.236; confidence interval: 0.090-0.549). In this case series, failure after hip reconstruction for children with CP was determined to be 13.1%. There was a higher risk associated with age under 6 at time of surgery or a preoperative MP >70%. Correction of acetabular dysplasia when AI is more than 25 degrees with acetabular osteotomy at time of hip reconstruction, exerted a protective effect against subsequent failure. Level III-retrospective case series.

Hip development after surgery to prevent hip dislocation in cerebral palsy: a longitudinal register study of 252 children

Background and purpose — Operative treatment of hip displacement in cerebral palsy (CP) includes adductor–psoas lengthening (APL) or varus derotation osteotomy (VDRO) of the proximal femur, sometimes combined with pelvic osteotomy. After both operations, there is a significant risk of relapse and need for reoperation. We used the migration percentage (MP) to compare the development of hip displacement after APL and VDRO. Patients and methods — All reported MP measurements for children treated with APL (n = 158) or VDRO (n = 94) and followed ≥ 3 years were obtained from the Swedish Surveillance Programme for CP. In children treated with bilateral surgery, the hip with the highest preoperative MP was analyzed. A mixed-effects model was used to estimate the development of MP with age for each child and the population mean. Results — The 104 hips that underwent APL without reoperation showed a gradually reduced MP postoperatively. The 54 hips that underwent a 2nd surgery with APL or VDRO because of redisplacement had a higher displacement rate preoperatively and continued displacement postoperatively but at a slower rate. The 94 hips that underwent VDRO showed an instantaneous decrease in MP postoperatively followed by a rate of increasing displacement. The 15 hips that underwent a 2nd VDRO had a higher rate of displacement both pre- and postoperatively. Interpretation — After APL, hip displacement either decreases or continues to increase but at a slower rate. After VDRO, the MP decreases momentarily but then gradually increases. The risk of reoperation is higher in children with a high preoperative displacement velocity and a high preoperative MP.

The impact of asymmetry on the radiographical outcomes following hip reconstruction in patients with cerebral palsy.

Purpose:The purpose of this study was to evaluate the impact of asymmetric hip dysplasia on the outcome of hip reconstruction in patients with cerebral palsy according to preoperative migration percentage (MP).Methods:This study was institutional review board-approved for retrospective cohort review. From 2008 to 2018, 65 patients met inclusion criteria: Gross Motor Function Scale Classification (GMFSC) III to V with spastic hips (MP > 30%) who underwent bilateral hip reconstruction, with a follow-up > 24 months. Main exclusion criteria: children with associated syndromes or chromosomal disorders. The cohort was subdivided into three groups according to preoperative MP difference between hips: Group A > 50%, group B 20% to 50% and Group C < 20%. Subsequently, the groups were analyzed individually and then compared. The asymmetry of extended abduction of the hip was also evaluated and separated into three groups: no asymmetry (< 20° difference), mild asymmetry (20° to 50° difference) and severe (> 50° difference).Results:In total, 65 patients underwent bilateral bony reconstructive surgery (130 hips). Mean age at surgery was 10.1 years (sd 3.6; 3.6 to 18.4). Mean age at follow-up was 14.7 years (sd 3.8; 8 to 21). Preoperative GMFSC distribution was grade III (four, 6%), IV (15, 23%) and V (46, 71%). In all, 21 symmetric hips (< 20% MP difference) had a preoperative MP difference of 9% and a follow-up MP difference of 18% (p > 0.05); 32 had a preoperative MP difference of 34% and a follow-up MP difference of 16% (p < 0.0001); 12 had a preoperative MP difference of 80% and a follow-up difference of 6% (p < 0.0001). According to pre- and postoperative abduction values, the mean high hip abduction preoperatively was 34° (sd 17°), whereas low hip abduction was 23° (sd 17°).Conclusion:Hips with asymmetrical dysplasia and/or abduction undergoing bilateral reconstructive surgery focused on symmetric abduction, and corrected dysplasia in patients with cerebral palsy has improved symmetry in hip abduction and MP. Obtaining this goal immediately postoperatively is maintained to medium-term follow-up.Level of Evidence:IV

The effectiveness of adding guided growth to soft tissue release in treating spastic hip displacement

BackgroundGuided growth at the proximal femur using one transphyseal screw corrects coxa valga and improves hip displacement in cerebral palsy. This study aimed to validate the effects of adding guided growth (GG) to soft tissue release (STR), in terms of decreasing the migration percentage (MP), compared to those with soft tissue alone. MethodsThis retrospective study comprised patients with cerebral palsy who underwent soft tissue release alone (Group STR) or soft tissue release plus guided growth (Group GG) for hip displacement (mean age, 8.1 years; mean follow-up, 4.9 years). Difference in the MP and rate of controlling MP <40% at 2 years postoperatively and rate of revision surgeries at 5 years postoperatively were compared between the groups. ResultsThe two groups were comparable in age, side, and gross motor function level, but Group GG (n = 24) had more severe hip displacement preoperatively than did Group STR (n = 64). Group GG had a significantly greater 2-year decrease in the MP (−14.8% vs. −11.8%, p < 0.05) than did Group STR. Among patients with a pre-operative MP >50%, the rate of MP <40% was greater in Group GG (73%) than in Group STR (41%). Revision surgeries, mainly repeated guided growth and soft tissue release, were comparable between the groups. ConclusionsThis is the first comparative study to support adding guided growth to soft tissue release, as it results in greater improvements in hip displacement than that with soft tissue release alone. Non-ambulatory patients or severe hip displacement with MP 50%–70% could benefit from this less aggressive surgery by controlling the MP under 40% without femoral osteotomy.

Remodelling of femoral head deformity after hip reconstructive surgery in patients with cerebral palsy.

AimsHip displacement, common in patients with cerebral palsy (CP), causes pain and hinders adequate care. Hip reconstructive surgery (HRS) is performed to treat hip displacement; however, only a few studies have quantitatively assessed femoral head sphericity after HRS. The aim of this study was to quantitatively assess improvement in hip sphericity after HRS in patients with CP.MethodsWe retrospectively analyzed hip radiographs of patients who had undergone HRS because of CP-associated hip displacement. The pre- and postoperative migration percentage (MP), femoral neck-shaft angle (NSA), and sphericity, as determined by the Mose hip ratio (MHR), age at surgery, Gross Motor Function Classification System level, surgical history including Dega pelvic osteotomy, and triradiate cartilage status were studied. Regression analyses using linear mixed model were performed to identify factors affecting hip sphericity improvement.ResultsA total of 108 patients were enrolled. The mean preoperative MP was 58.3% (SD 31.7%), which improved to 9.1% (SD 15.6%) at the last follow-up. NSA and MHR improved from 156.5° (SD 11.5°) and 82.3% (SD 8.6%) to 126.0° (SD 18.5°) and 89.1% (SD 9.0%), respectively. Factors affecting the postoperative MHR were preoperative MP (p = 0.005), immediate postoperative MP (p = 0.032), and history of Dega osteotomy (p = 0.046).ConclusionWe found that hip sphericity improves with HRS. Preoperative MP, reduction quality, and acetabular coverage influence femoral head remodelling. We recommend that surgeons should consider intervention early before hip displacement progresses and that during HRS, definite reduction and coverage of the femoral head should be obtained.Cite this article: Bone Joint J 2021;103-B(1):198–203.

Reconstructive hip surgery in children with cerebral palsy: factors influencing risk of femoral head avascular necrosis.

Femoral head avascular necrosis (AVN) is a complication of hip reconstruction in children with cerebral palsy (CP) with uncertain incidence. The purpose of this study was to establish the rate of AVN in children undergoing hip reconstruction and to identify the factors associated with AVN. Medical records and radiographs of patients aged 1-18 with a diagnosis of CP who have undergone hip reconstruction over a 9-year period (2010-2018) with at least 1-year follow-up were reviewed. Age at time of surgery, sex, Gross Motor Function Classification System (GMFCS), procedure(s), preoperative migration percentage (MP), and signs of AVN on anterioposterior pelvis radiographs at routine follow-up visits (3 months, 6 months, and years 1-9, annually) according to the Bucholz-Ogden (BO) and Kalamchi-MacEwen (KM) classification systems were recorded. Univariate analysis was used to test for significance. Three hundred forty-nine hips in 209 patients met our inclusion criteria. Eleven hips (rate; 3%), in 11 patients, developed AVN. Classification of AVN was found to consist of: class I-4 (36%), class II-1 (9%), class III-[BO: 4 (36%)] [KM: 3 (27%)], and Class IV-[BO: 2 (18%)] [KM: 3 (27%)]. Average follow-up was of 3.5 years. The AVN cohort displayed older age (11.0 ± 2.8 vs. 8.1 ± 3.4; P = 0.005). Open reduction was associated with increased AVN, occurring in 9% of the hips (P = 0.004). No significant association was found between preoperative MP, GMFCS, or acetabular osteotomy. The method of open reduction (anterior vs. medial) was not significantly associated with AVN (P = 0.4471). In this large series, the observed rate of AVN was 3%, associated with open reductions at time of hip reconstruction. If possible, closed reduction would be preferred at time of hip reconstruction in children with CP to lower the risk of AVN. Level of evidence: III.

Outcome of Femoral Varus Derotational Osteotomy for the Spastic Hip Displacement: Implication for the Indication of Concomitant Pelvic Osteotomy.

No previous studies have suggested a reliable criterion for determining the addition of a concomitant pelvic osteotomy by using a large patient cohort with quadriplegic cerebral palsy and a homogenous treatment entity of femoral varus derotational osteotomies (VDRO). In this retrospective study, we examined our results of hip reconstructions conducted without a concomitant pericapsular acetabuloplasty in patients with varying degrees of hip displacement. We wished to investigate potential predictors for re-subluxation or re-dislocation after the index operation, and to suggest the indications for a simultaneous pelvic osteotomy. We reviewed the results of 144 VDROs, with or without open reduction, in 72 patients, at a mean follow-up of 7.0 (2.0 to 16.0) years. Various radiographic parameters were measured, and surgical outcomes were assessed based on the final migration percentage (MP) and the Melbourne Cerebral Palsy Hip Classification Scale (MCPHCS) grades. The effects of potential predictive factors on the surgical outcome was assessed by multivariate regression analysis. A receiver operating characteristic (ROC) curve analysis was also performed to determine whether a threshold of each risk factor existed above which the rate of unsatisfactory outcomes was significantly increased. In total, 113 hips (78.5%) showed satisfactory results, classified as MCPHCS grades I, II, and III. Thirty-one hips (21.5%) showed unsatisfactory results, including six hip dislocations. Age at surgery and preoperative acetabular index had no effects on the results. Lower pre- and postoperative MP were found to be the influential predictors of successful outcomes. The inflection point of the ROC curve for unsatisfactory outcomes corresponded to the preoperative MP of 61.8% and the postoperative MP of 5.1%, respectively; these thresholds of the pre- and postoperative MP may serve as a guideline in the indication for a concomitant pelvic osteotomy. Our results also indicate that the severely subluxated or dislocated hip, as well as the hip in which the femoral head is successfully reduced by VDRO but is still contained within the dysplastic acetabulum, may benefit from concomitant pelvic osteotomy.

Soft tissue surgery as an initial treatment for hip displacement in spastic cerebral palsy.

Objective: To use the measurement of migration percentage (MP) to evaluate the long-term radiographic results of soft tissue surgery as the first treatment for hip displacement in spastic bilateral cerebral palsy. A secondary objective was to identify predictive factors of stability (i.e., less than 30% of MP in the long term), after surgical correction. Methods: In this longitudinal cohort study, we reviewed the electronic medical records and radiographs of all consecutive patients with cerebral palsy operated for the correction of hip displacement between 1984 and 2013 in a referral orthopedic public hospital in Brazil. Patients were included if they had received, as the first surgical procedure, soft-tissue release. All surgeries were bilateral and symmetrical. We used the available radiographs to evaluate the migration percentage (MP), acetabular index (AI), pelvic obliquity (PO) angle, head-shaft angle (HSA), congruence and femoral head sphericity, and function using the GMFCS (Gross Motor Function Classification System). Results: we included 93 patients, all operated before being 12 years old, with follow-up of 10 years in average, 73 (78%) of them with good results (MP < 30%). We found association between preoperative MP ≤ 40%, AI ≤ 25°, and postoperative symmetry with good results, with a cut-off value of 38% of MP and 27° of acetabular index being predictive. Discussion: The role of soft tissue releases remains controversial owing to small sample sizes, heterogeneity, variety range of ages, definitions used for outcome, and lack of statistical quality. Our results were better in combined tenotomies, in diparetic patients aged more than six years, and in patients with lower initial values of MP and AI. Radiographic variables had good correlation with each other and association with results, with cut-off values for MP and AI PRE.

Femoral and pelvic osteotomies for severe hip displacement in nonambulatory children with cerebral palsy: a prospective population-based study of 31 patients with 7 years’ follow-up

Background and purpose — There is no consensus regarding the optimal treatment of hip displacement in children with cerebral palsy (CP). This prospective study assessed the outcome of femoral and pelvic osteotomies for severe hip displacement in nonambulatory children and analyzed prognostic factors for outcome.Patients and methods — 31 nonambulatory children (20 boys), recruited from a population-based screening program, consecutively underwent unilateral (23) or bilateral (8) osteotomies and bilateral soft-tissue releases at a mean age of 6.1 years (2.2–9.9). The procedures were femoral varus osteotomy alone (20 hips) and combined Dega-type pelvic osteotomy and femoral osteotomy (19 hips). Final outcome was termed good if the patient had not undergone further bony surgery and migration percentage (MP) was < 50%. The mean follow-up time was 7.1 years (3.8–11).Results — The mean preoperative MP was 69% (36–100). The outcome was good in 22 patients (29 hips) and poor in 9 patients (10 hips). Mean time to failure was 3.6 years (1.0–6.0). GMFCS level V and high MP 1-year postoperatively were statistically significant risk factors for poor final outcome. There was a higher rate of good outcome after combined osteotomies compared with isolated femoral osteotomy, but the difference was not statistically significant (p = 0.2).Interpretation — Better primary correction was obtained after combined femoral and pelvic osteotomies than after isolated femoral osteotomy, indicating that combined osteotomies are the preferred method in hips with the most severe degrees of displacement. Prophylactic femoral osteotomy of the contralateral non-subluxated hip is hardly indicated.

Guided Growth Improves Coxa Valga and Hip Subluxation in Children with Cerebral Palsy.

Spastic hip subluxation or dislocation that is associated with an excessive coxa valga deformity is a common pathologic condition in children with cerebral palsy (CP) that is often treated with large bone reconstructive procedures. Guided growth techniques (such as stapling, plate, or transphyseal screw) have been widely used to alter the growth axis in patients with a lower-limb deformity but only a few reports have described their use in patients with coxa valga deformities. (1) Does guided growth surgery using a transphyseal screw combined with adductor tenotomy prevent progressive coxa valga deformity and lateral hip subluxation in children with CP? (2) What factors influence the correction of coxa valga deformity and the success of hip stabilization? (3) What complications were associated with this operation and how often did children treated with it undergo reoperation? From 2012 to 2016, at our institution, three authors (H-CH, KNK, K-WW) retrospectively studied data on children with CP who underwent guided growth of the hip for progressive bilateral hip subluxation associated with coxa valga deformities. A single percutaneous screw was inserted across the inferomedial portion of proximal femoral physis in an AP view and centered along femoral neck in lateral view under fluoroscopy guidance. During the period, we treated 25 consecutive children with CP who had progressive hip subluxation with coxa valga deformities. The indications for surgery were migration percentage > 30% and head-shaft angle > 155° with at least 2 years growth remaining. Of those, 13 patients underwent guided growth alone, and 48% (12) underwent a combination of guided growth and adductor tenotomy. Of the 25 patients treated with this approach, 96% (24) were available for follow-up with complete data at a minimum of 2 years follow-up (mean 50 months; range 25 to 72). All children (17 boys and seven girls; 48 hips) underwent surgery at a mean age of 8 years (range 5 to 12). With regard to the gross motor function classification system, three patients were Level 1, four patients were Level II, seven patients were Level III, seven were Level IV, and three were Level V. Radiographic parameters including the head-shaft angle, Hilgenreiner's epiphyseal angle, acetabular index, and Reimer's migration percentage were assessed before surgery and at the latest follow-up examination by one author (H-CH). Complications and reoperations were assessed by chart review. During the period in question, we generally offered secondary reconstructive surgery to patients who underwent a guided growth procedure once their subluxation progressed. With the data available, the coxa valga and lateral hip subluxation improved in terms of the reduction of head-shaft angle by a mean of 13° ± 7° (95% CI 11 to 15; p < 0.001) and the reduction of the migration percentage by 10% ± 11% (95% CI 7 to 13; p < 0.001). After controlling for potentially confounding variables like gender, gross motor function classification system, Hilgenreiner's epiphyseal angle and acetabular index, we found that longer follow-up duration (r = 0.234; p < 0.001) and a smaller preoperative migration percentage (r = -0.258; p = 0.004) were associated with larger changes in the head-shaft angle. In terms of complications, we found that the proximal femoral physis grew off the screw tip in 44% (21 of 48 hips) at a mean of 28 months. Among these, 31% of hips (15 of 48) in 33% of patients (eight of 24) underwent replacement with a longer screw. Among the 17% of hips (eight of 48) in 21% of patients (five of 24) who had progressive lateral subluxation and underwent secondary reconstructive surgery, we found that their preoperative acetabular index was higher (mean 29° versus 21°; p < 0.001), as was their head-shaft angle (mean 166° versus 162°; p = 0.045), and migration percentage (mean 54% versus 36 %; p < 0.001). Although guided growth with single transphyseal screw did not create as large a degree of varus as proximal femoral osteotomy, it did stabilize the hip in children with cerebral palsy with migration percentage less than 50% in our series. It is a simple procedure that can be of benefit to children with cerebral palsy with unstable hip. Reoperation in patients where the physis has grown off the screw tip can be a problem; fortunately, it is a rather minor procedure to replace with a longer screw. Level III, therapeutic study.

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.

Minimally invasive Dega acetabuloplasty for the treatment of neuromuscular hip dysplasia

Background: Dega acetabuloplasty is used in the management of neuromuscular hip dysplasia. A minimally invasive technique may decrease perioperative morbidity while allowing for adequate reduction and ensuring stability. We sought to determine the impact of a minimally invasive Dega acetabuloplasty (MID) on hip stability after neuromuscular hip reconstructions. Methods: A retrospective review was performed of consecutive patients with cerebral palsy (GMFCS IV/V) and neuromuscular hip dysplasia undergoing bony reconstruction including a varus derotational osteotomy (VDRO) of the femur and a Dega acetabuloplasty. Clinical records were reviewed to evaluate preoperative comordibities and clinical complications. Review of pelvic radiographs preoperatively and at follow-up evaluated correction of acetabular index, migration percentage, and the presence of an intact Shenton’s arc. Results: Forty-two patients (45 hips) underwent MID surgery as part of a reconstructive approach for neuromuscular hip subluxation or dislocation. Preoperative migration percentage averaged 61.1±4.0% (range, 39-100%). In addition to bony reconstructions, 91.4% of hips had soft-tissue balancing. Patients had an average estimated blood loss of 102±69.9 cc, mean operative time of 165±44 min, and an average length of stay of 3.2±1.3 days. No patient required reoperation. Operative intervention resulted in a mean migration percentage of 12.1%±2.5 and residual acetabular index of 16.0±8.7 degrees with 84.4% (38 of 45) of hips having an intact Shenton’s arc at 1-year of follow-up. Conclusions: The MID provides acceptable rates of postoperative hip stability at 1 yr with low blood loss, surgical time, length of stay, and postoperative medical complications. Level of Evidence: Level IV.

Outcomes of Isolated Varus Derotational Osteotomy in Children With Cerebral Palsy Hip Dysplasia and Predictors of Resubluxation.

The appropriate intervention for hip subluxation or dislocation in children affected by cerebral palsy (CP) remains controversial. The purpose of this retrospective study was to report radiographic and clinical outcomes following isolated femoral varus derotational osteotomy (VDRO) in children with CP hip dysplasia. Risk factors for resubluxation and avascular necrosis (AVN) were also examined. A cohort of 100 patients (199 hips) with CP treated with isolated VDRO between 2003 and 2009 was reviewed. All but 1 patient received bilateral surgery. Patients were followed for an average of 5.4 years (range, 1.03 to 10.20 y). Anteroposterior pelvic radiographs were used to assess migration percentage (MP), Shenton's line, and presence of AVN. Resubluxation was defined as a postoperative break in Shenton's line. Radiographic outcomes and risk analysis was performed in the 91 subjects (179 hips) with radiographic follow-up >1 year. Significant improvement was observed in MP, and all hips had a reconstituted Shenton's line following surgery. Over the course of follow-up, 16% of hips were noted to have a repeat break in Shenton's line. Univariate risk analysis showed preoperative MP, Gross Motor Function Classification System (GMFCS) level, and age at surgery were risk factors for a recurrent line break. Preoperative MP and GMFCS level were found to be predictors of resubluxation in multivariate analysis. AVN was detected in 10 hips (5.7%). GMFCS level V patients were more at risk for resubluxation, but less at risk for AVN when compared with ambulatory (GMFCS I/II/II) patients and GMFCS level IV patients. Performing a VDRO without additional procedures provided a stable and concentrically reduced hip joint in this population of children with CP. Attention should be paid to initial ambulatory status during the postoperative period. Concomitant procedures such as pelvic osteotomy should be considered for patients of GMFCS level IV and V, as these patients were more at risk for recurrent subluxation. Level III-retrospective comparative study.

Surgical reconstruction of hip subluxation and dislocation in children with cerebral palsy.

This study aims to review the efficacy of femoral varus derotation osteotomy (VDRO) and Dega transiliac osteotomy in the treatment of hip subluxation and dislocation of cerebral palsy (CP) patients. This retrospective study included 25 hips of 22 CP patients (9 males, 13 females; mean age 8.7 years; range 4 to 18 years) who were operated due to hip subluxation and dislocation between July 2010 and December 2015. The mean follow-up period was 36.1±10.4 months (range, 20 to 65.6 months). Femoral VDRO and Dega transiliac osteotomy were performed in all cases. None of the patients were administered cast immobilization postoperatively. Patients were evaluated clinically with gross motor function classification system preoperatively and at the follow-up period. Acetabular index (AI), migration percentage (MP), and neck-shaft angle (NSA) were measured and documented by pelvic radiographs taken pre- and postoperatively and at the follow-up period. Intra- and postoperative complications were recorded. Gross motor function classification system scores improved in 16 patients. Mean AI was 33.2° preoperatively and 20.4° postoperatively. In preoperative period, MP and NSA were 72.7% and 160°, respectively, which improved to 24.3% and 130°, respectively, postoperatively. The postoperative improvement in AI, NSA and MP were statistically significant (p<0.001). We performed revision surgery due to implant failure in two patients and detected hip subluxation due to increased pelvic obliquity in one patient who had thoracolumbar scoliosis. In CP patients, reconstruction of hip subluxation and dislocation with femoral VDRO and Dega transiliac osteotomy establish femoroacetabular congruency. Without any cast immobilization, early physical therapy is encouraged for immediate recovery.