In this paper a review is given first on the various techniques in the operative treatment of the idiopathic necrosis of the femoral head in the adult. Because of the high rate of pseudarthrosis (50%) arthrodesis is rarely done today. Decompression of the medullary space is highly successful in 80-90%, but only in stage I and II. For stage III of the disease different osteotomies of the proximal femur are recommended. Artificial joint replacement is usually done in stage IV. Our case material consists of 46 operations in 37 patients (27 endoprostheses, 16 osteotomies of the proximal femur, 3 fillings with spongiosa), artificial joint replacement was always done in stage IV, the other operations in stage III of the disease. The clinical results are better than the radiological ones; in 50% of the intertrochanteric osteotomies necrosis was progressive within 4 years after operation, in 1/3 of the endoprostheses radiological loosening and periarticular calcification developed within the same period. In consideration of the unfavorable radiological findings in our case material we are going to initiate functional examination of the femoral head, because this might lead to earlier diagnosis and because central decompression of the medullary space - which is combined with this procedure - brings about a healing quotient of 80-90% in stage I and II (Arlet und Ficat, 1968; Ficat, 1983).