Prognostic factors for trochanteric overgrowth after containment treatment in Legg–Calvé–Perthes disease

Trochanteric overgrowth is one of the major residual deformities after the treatment of Legg-Calvé-Perthes disease. The present study was designed to determine the predictive factors for trochanteric overgrowth at skeletal maturity in patients with the disease. Medical records and radiographs of 45 Legg-Calvé-Perthes disease patients who were treated with containment therapy at our institution were reviewed retrospectively. Univariate analysis was carried out to determine the predictors for trochanteric overgrowth using the Mann-Whitney U-test for continuous variables and the Pearson test for categorical variables. Independent multivariate predictors were identified using logistic regression analysis. Trochanteric overgrowth, defined as articulotrochanteric distance less than +5 mm, was observed in 10 patients (22%). There was a strong correlation between the final Stulberg outcome and trochanteric overgrowth (P=0.0003). Lateral pillar height was the only statistically significant predictor for trochanteric overgrowth at skeletal maturity in univariate and multivariate analyses. The risk for the development of trochanteric overgrowth was much greater in the lateral pillar C hip (44%) than in the lateral pillar B or B/C hip (10%). For the patients with decreased lateral pillar height, a careful follow-up is necessary to make an early decision of prophylactic epiphyseodesis of the greater trochanter.