A perfect technic of implantation is the fundamental factor to guarantee a postoperative course free of complications. The position of the prosthesis and a high initial stability are important factors, too. In the OHH 1 561 patients were given 1 973 cemented total endoprostheses from 1968 to 1978. From 1975 to 1980, an additional number of 212 total endoprostheses without cement (ceramic prostheses) were implanted. The following aseptic complications were most common: (1) loosening, (2) luxation, (3) fractures of the shaft of the prosthesis, (4) bursting of the femur-shaft, (5) protrusio acetabuli, and (6) periarticular deposition of calcium. The rate of complications in cemented total endoprostheses was 2.7%, in cement-free endoprostheses 5.7%. In 10.3% of the cemented endoprostheses early complications were observed; among the patients with cement-free endoprostheses there occurred one luxation and one fatal case (pulmonary embolism). Late complications of the cemented endoprostheses were seen in 8%; among the cement-free endoprostheses 4 loosenings of the acetabulum, 3 loosenings of the shaft, 1 protrusio acetabuli and 1 fracture of the ceramic neck were found. 77.5% of the patients, with cemented prostheses judged their ability to walk as much improved, compared to the previous state. In 15.7% the results were unchanged, in 6.7% the state had deteriorated. Among the patients with cement-free endoprostheses 61% considered their walking ability to be much better, 29% moderately improved and 8.5% unchanged. 1% felt worse than before surgical treatment.