In the last 5 years the authors have installed Wagner hip joint cup prostheses in 260 patients. Of these, 211 were implanted with an iliofemoral approach after Smith-Petersen, severing the pelvitrochanterian musculature, and 49 with a lateral approach after Watson-Jones, modified after Harris, with temporary ablation of the trochanter major. Altogether, 160 of the patients thus treated were followed up 3, 6, 18, 24, 30 and 36 months after surgery. The most common postoperative complication, found in 36% of those examined, was periarticular calcification, which was rated as severe in 5%, moderate in 15% and slight in 16%. Even though the periarticular ossifications did not necessarily lead to severe restrictions of movement, the patients with severe and moderate calcifications who were examined after 3 years were found to have a reduction of function of approx. 24% in flexion and extension, approx. 50% in abduction and adduction and approx. 57% in internal and external rotation compared with preoperative findings. In contrast, patients with no significant periarticular ossifications were found to have a definite improvement in motility 3 years after surgery as compared to their preoperative conditions. Further important complications were 2 infections, 3 fractures of the neck of the femur, 3 slipped prostheses and 23 cases of loosening of the prosthesis. The number of loosened prostheses (9% of those examined) represents a marked increase as compared to the loosening rate with conventional total hip replacements.(ABSTRACT TRUNCATED AT 250 WORDS)