To determine the developmental patterns of 4 major deformities of femoral head commonly observed in Legg-Calve-Perthes disease (LCPD): coxa plana, coxa magna, coxa vara, subluxation.

We reviewed the clinical records and radiographs of 85 unilateral LCPD children who were followed up from the early stage of disease to full skeletal maturity. Four major deformities were measured and observed during 3 periods: the active disease stages of avascular necrosis and fragmentation, the healing stage, and skeletal maturity.

All four deformities were first observed at early stages of the disease, avascular or fragmentation stage. Appearance rates were 79% in coxa plana, 28% in coxa magna, 35% in coxa vara, and 27% in subluxation. The gradual progression of deformities with time which was demonstrated at the healing stage and at skeletal maturity were observed in all except subluxation. And this gradual increase was supposed to be dependent on the normal bony growth with aging.

We determined the developmental pattern of major deformities of the femoral head. And this determination will help to understand the natural course of deformity which is clinically important in terms of late osteoarthritis.