In a multi-center study in 14 trauma hospitals 328 patients with fractures and osteosyntheses of the femoral neck were investigated with reference to time between accident and operation implants used, early and late complications, and results in the years from 1974 to 1987. A follow-up examination was possible in 266 patients a mean of 46.7 months after their accidents. General postoperative complications were recorded in 12.2% and local complications in 11.6%. In 9.8% pseudarthrosis was observed, in 26% an aseptic femoral head necrosis and in 2.4% deep infections. Functional results were excellent to fair in 75%. The best results (significantly better than in other groups) were obtained in patients who were operated on early (< 24 h after trauma) (P < 0.05) and those in whom dynamic hip screws (DHS) were used (P < 0.01). Of all cases of aseptic necrosis 70% were seen within 3 years and 86% within 6 years after trauma. The rate was dependent on the degree of dislocation of the fracture (Garden III and IV), the time from trauma to operation, and the implant used (130 degrees blade plate 30.5%, DHS 9.2%).