Valgus Femoral Osteotomy for Noncontainable Perthes Hips: Prognostic Factors of Remodeling

Abstract

Background: The authors have performed valgus femoral osteotomy (VFO) with rotational and sagittal components for Legg-Calve-Perthes disease hips with hinge abduction. We analyzed skeletally mature patients to determine: (1) whether VFO improved hip function; (2) whether favorable radiographic remodeling of the hip occurred; and (3) whether any clinical or radiographic factors were associated with remodeling of femoral head deformity. Methods: Thirty-one patients (31 hips, 25 boys and 6 girls) who underwent VFO between 1986 and 2007, and subsequently followed until skeletal maturity constituted the study cohort. The mean age at surgery was 9.4 years (range, 3.5 to 15 y) and the mean age at the most recent follow-up was 20.2 years (range, 14.6 to 28.3 y). Clinical outcomes were evaluated using Iowa Hip Scores and ranges of hip motion. Radiographic outcomes were assessed with respect to the radiographic indices for femoral head deformity and subluxation. Clinical and radiographic parameters were analyzed to find correlations with the femoral head remodeling (preoperative to final follow-up changes in deformity index). Results: Iowa Hip Score improved from 71 (30 to 91) to 92 (76 to 100). Ranges of hip abduction, internal rotation, and external rotation increased. At last follow-up evaluations, mean Mose sphericity index of the femoral head was 4.2mm (range, 0 to 13 mm) and femoral heads had 4 Stulberg type II, 21 type III, and 6 type IV deformity. Overall radiographic indices for femoral head deformity and subluxation did not change during follow-up period except decreased medial joint space, but greater amount of preoperative to final follow-up changes in deformity index was associated with younger age (< 10 y) and earlier disease stages (fragmentation and early reossification stage) at time of surgery. Conclusions: VFO modified to accommodate the various hinging patterns of Legg-Calve-Perthes disease hips was found to beneficially improve hip function at skeletal maturity. Although overall radiographic remodeling was not definite, favorable remodeling of the femoral head can be expected when younger patients undergo this procedure at the fragmentation or early reossification stage.