Between 1978 to 1994, 110 osteotomies were performed in 94 patients. Fifty hips (40 patients) were included in this study. Six hips were in stage II avascular necrosis (Arlet-Ficat staging) and 44 hips were in stage III. In 14 patients an etiologic association was discovered, the remaining 26 were considered idiopathic. The postoperative assessment (Harris score) showed that there is no statistic differences between sexes. Results strongly depend on the amplitude of the necrotic (Kerboul) angle (p < 0.01), the preoperative mobility of the hip (p < 0.01), and age. The best postoperative results are usually obtained in young, active, patients with unilateral involvement, a necrotic angle of less than 200 degrees, a good preoperative range of hip motion, and in which the osteotomy is performed before the collapse of sequestrum.