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

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.