Effect of Pelvic Osteotomy in the Skeletally Immature on Acetabular Coverage

BACKGROUND: Although pelvic osteotomy in children has been effective in re-establishing containment of the hip joint, its impact on hip joint development with respect to acetabular coverage is ill defined. PURPOSE: The purpose of this study is to determine the prevalence of acetabular overcoverage in patients who had pelvic osteotomy during childhood and its impact on patient function. PATIENTS AND METHODS: Between 1980 and 2008, all patients who had a pelvic osteotomy done at our institution for non-neuropathic hip dysplasia (DDH) or secondary to Legg-Calvé-Perthes disease (LCP) prior to skeletal maturity were reviewed. A clinical assessment and the WOMAC, UCLA Activity Score, Marx activity score, and SF-36 quality-of-life questionnaires were completed. A standardized AP pelvic X-ray was performed to determine the acetabular coverage, signs of retroversion, and degenerative changes. RESULTS: Twenty-eight patients (32 hips) were identified, of which 14 (9 DDH, 5 LCP) agreed to participate. Impingement sign was positive in eight patients (six DDH, two LCP). Crossover and ischial spine signs were each present in ten hips. Tonnis grades were: 0 in 1 hip, 1 in 10 hips, 2 in 2 hips, and 3 in 1 hip. The mean Tonnis angle was 11.6 ± 8.6°. The mean CE angle was 24.0 ± 15.9° with six hips having a CE angle <20° and one hip with a CE angle >40°. There was no correlation between crossover sign or ischial sign and Tonnis grade (p = 0.739), hip pain (p = 0.520), or impingement sign (p = 1.00). CONCLUSIONS: Acetabular overcoverage is common in patients who underwent pelvic osteotomy during childhood. No correlation was identified between retroversion and hip pain in our patient cohort.