Legg-Calvé-Perthes disease and slipped capital femoral epiphysis: major developmental causes of femoroacetabular impingement.

Problematic femoroacetabular impingement frequently is seen following Legg-Calvé-Perthes disease (LCPD) in young children and following slipped capital femoral epiphysis (SCFE) in older children and adolescents. Although symptoms may be mild in adolescents and young adults, chondral damage following LCPD and SCFE deformity is cumulative and irreversible, which has led to a recent emphasis on the consideration of early treatment. The surgical dislocation approach and improved MRI and three-dimensional CT have revealed common patterns of deformity and structural damage. The surgical dislocation approach is a superb diagnostic tool unmatched in assessing complex dynamic impingement patterns, and it allows direct treatment of deformity through recontouring of the head and neck and, in unhealed SCFE, epiphyseal realignment. The contemporary hip-preserving management of deformity following LCPD and SCFE is changing rapidly, necessitating careful evaluation of new treatment methods.