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 sub-luxation. The operation should be performed before the hip displacement reaches 50%.