[Acetabular convexity--a specific addition to total endoprosthetic hip replacement].

Between 1. 1. 1977 and 30. 6. 1988, 1470 total hip prostheses were implanted at the 1st Orthopedic Clinic in Bad Abbach/Regensburg. In 101 cases (82 patients, average age 54.8 years) the acetabular convexity was built up at the same time. This is considered indicated if the acetabulum is too shallow and thus provides insufficient lateral or dorsolateral countersupport. The main area of indication is dysplasia-coxarthrosis and congenital dislocation of the hip, destructive coxitis in chronic polyarthritis or juvenile chronic arthritis, and loosened prostheses. The material used for building up the convexity is a block of corticocancellous bone, which is fixed ventrolaterally to dorsolaterally to the ilium by osteosynthesis. Autologous material was used in 88 cases and homologous material in 13. Sixty-one patients with a total of 77 built-up convexities were followed up. In 92.2% a bony bridge between the corticocancellous block and the rising branch of the ilium was fund. The method described is a valuable addition to replacements in case of extreme hip joint changes and replacement operations. In the authors' opinion it has considerable advantages over supporting shells and similar materials.