Success in treating the contralateral hip in cerebral palsy patients with unilateral hip subluxation

Abstract

Introduction: The role of non-operative treatment in the non-subluxed hip in cerebral palsy patients undergoing surgery for the subluxed hip remains unclear. We investigated the outcome of contralateral hips in patients who received surgery for unilateral hip subluxation. Methods: We reviewed all cases of patients with cerebral palsy who had hip surgery between 1990 and 2014 in our institute. Hip subluxation was defined as Reimer’s Migration Index (RMI) of >30%. We included only patients with unilateral hip subluxation and excluded those with follow-up of <5 years. Failure (defined as latest RMI >40% or requiring subsequent surgery) rate and baseline characteristics were compared between operated and non-operated groups Results: Twenty-six patients met our study criteria (mean follow-up, 10 years) with 12 non-operated and 14 operated cases. The failure rate in the non-operated group was 1/12 (8%) versus 1/14 (7%) in the operated group, but this was not statistically significant. The two groups were similar in age, Gross Motor Function Classification System, preoperative RMI and acetabular index. The only difference is the preoperative abduction range — the non-operated group has a better mean abduction (56° vs 37°, p<0.05). Conclusion: Our study suggests that patients with cerebral palsy with unilateral hip subluxations do not have higher rates of failure in the contralateral, non-operated hip, provided that they have good abduction range (>50° in our study). This suggests that abduction range should be a key factor in considering non-operative treatment on the contralateral hip.