ABSTRACT
BACKGROUND: Triple pelvic osteotomy (TPO) is a treatment option in children and adolescents with residual acetabular dysplasia after developmental dislocation of the hip (DDH). However, TPO to redirect the acetabulum is often blamed for anterior and lateral overcoverage of the femoral head. The main objectives of this study were to assess the potential clinical impact, frequency, and radiological features of acetabular overcorrection. Evidence of post-operative remodelling and associations linking younger age at surgery and/or dysplasia severity to the existence and magnitude of overcorrection were sought. HYPOTHESIS: Acetabular overcorrection has little or no clinical impact. PATIENTS AND METHODS: TPO was performed on 41 hips in 31 patients at a mean age of 6.3 years (range, 3.0-15.2 years). Mean follow-up was 13.8 years (range, 5.4-28.7 years) and mean age at last re-evaluation was 22.1 years (range, 13-39 years). Clinical outcomes were assessed based on the Harris Hip Score (HHS) and Postel-Merle d'Aubigné (PMA) score. Radiographs were used to look for a cross-over sign (CO+) and to measure the vertical-centre edge (VCE) and vertical-centre anterior (VCA) angles and the acetabular index (AI). Overcorrection was defined as AI≤0° and/or VCE≥35° and/or VCA≥40° and/or CO+. RESULTS: The HHS and PMA score values were good or excellent for 39 (94%) hips. One or more parameters indicated overcorrection of 33 (80.5%) hips. No significant differences were found between the overcorrected hips and the hips with normal parameters. DISCUSSION: TPO effectively corrects residual acetabular dysplasia. Overcorrection is common in all three planes but has little clinical impact in young adults. The high frequency of overcorrection mandates a careful pre- and intra-operative evaluation of acetabular version. LEVEL OF EVIDENCE: IV, retrospective study.
