The outcome of treatment of nonmetastatic high-grade osteosarcoma in the distal part of the femur was studied in 227 patients from twenty-six institutions. Eight of the seventy-three patients who had had a limb-salvage procedure and nine of the 115 patients who had had an above-the-knee amputation had a local recurrence, but there was no local recurrence in the thirty-nine patients who had had a disarticulation at the hip. There were no significant differences in the rate of survival or in the duration of the postoperative disease-free period between the three groups. One hundred and nine patients (48 per cent) were alive at an average of eleven years after the operation, and ninety patients (40 per cent) remained continuously disease-free. An additional operation on the limb was necessary more often for patients who had had a limb-salvage procedure than for those who had had an amputation. Function in seventy-eight living patients was assessed with the system of the Musculoskeletal Tumor Society for evaluation of function and by the functional assessment portion of the 1989 scoring system of the Knee Society; the scores were higher for the patients who had had a limb-salvage procedure than for the two groups of patients who had had an amputation. No difference was identified between the groups with regard to the patient's acceptance of the postoperative state, the ability to walk, or the amount of pain. The quality of life was evaluated for twenty-nine patients with a series of complex questionnaires.(ABSTRACT TRUNCATED AT 250 WORDS)