Can Over-containment Prevent Recurrence in Children With Cerebral Palsy and Hip Dysplasia Undergoing Hip Reconstruction?

Abstract

Introduction: Hip reconstruction is often necessary in children with cerebral palsy (CP) but is associated with high failure rates. Over-containment deeply seats the hip within the acetabulum at the time surgical reconstruction. The goal of this study is to evaluate the effect of over-containment on radiographic outcomes and failure rates in children with CP undergoing hip reconstruction. Methods: This study is a retrospective chart review of children with CP that underwent hip reconstruction between 2010 and 2019 with at least 2 years of radiographic follow-up. Migration percentage (MP), acetabular index (AI), and neck shaft angle (NSA) were recorded preoperatively, postoperatively and throughout follow-up. Failures were defined as a MP at latest follow-up ≥30% or need for revision hip reconstruction. Hips were divided into groups based on postoperative MP—group 1 (over-containment group) had a MP≤0% and group 2 had an MP>0%. Radiographic parameters and failure rates were compared across Gross Motor Functional Classification Score (GMFCS) level, age at the time of surgery, and degree of preoperative subluxation. Results: A cohort of 108 patients (197 hips) with an average age of 7.3±3.2 years met inclusion criteria with an average follow-up of 49.6 months (range: 24 to 118 mo). There were 147 hips in group 1 and 50 hips in group 2. At latest follow-up, group 1 demonstrated lower MP, AI, and NSA in comparison to group 2. The overall failure rate in our cohort was 8.1% (16 hips). Failure rates trended lowest in hips that were over-contained (6.1% v. 14.0%) although not statistically significant. Over-containment resulted in significantly lower failure rates in GMFCS IV/V hips, children under age 6 at the time of surgery and those with a higher degree of preoperative hip displacement (MP>50%). Conclusions: Over-containment at the time of hip reconstruction can positively affect radiographic outcomes and failure rates in children with CP. Over-containment should be considered in hips at high risk of failure, especially non ambulatory children with significant hip subluxation at an early age. Level of Evidence: Level III—retrospective comparative study.

Femoral Head Deformity Associated With Hip Displacement in Nonambulatory Cerebral Palsy: Results at Skeletal Maturity

“…By corollary, protection of the femoral head by overcontainment (MP ≤ 0%) may prevent progressive femoral head deformity by shielding it from external pressure, allowing for better force distribution across the epiphysis. Zakrzewski 19 reported lower failure rates and better radiographic parameters for hips that underwent overcontainment versus those with an MP > 0%, although FHS was not assessed in their study.…”

What’s New in Pediatric Orthopaedics

“…A review of hip reconstructions in patients with cerebral palsy found a failure rate of 13% and found that a patient age of <6 years or MP >70% was associated with a higher risk of failure, whereas performing a pelvic osteotomy for an acetabular index of >25° was protective against failure 48 . A separate study found that over-containment can decrease the risk of failure, especially in nonambulatory children with substantial hip subluxation at an early age 49 .…”

Children’s orthopaedics

“…A group from Cincinnati (Ohio, USA) sought to evaluate their clinical and radiological experience of over-containment in a single institutional retrospective study. 3 The recorded CP patients undergoing hip reconstruction over a nine-year period, with at least two years of follow-up, were examined. Migration percentage (MP), acetabular index (AI), and neck-shaft angle (NSA) were recorded pre- and postoperatively, and through follow-up, with a MP at latest follow-up ≥ 30%, or the need for revision surgery, defined as a failure of treatment.…”