[Results of cementless implantation of 150 "Erlangen Model" hip prostheses of titanium alloy Ti Al5 Fe2.5].

Between March 17, 1984 and August 20, 1987, 142 patients with osteoarthritis of one or both hips were treated by joint replacement with the uncemented "Erlangen" hip prosthesis (Prof. H. Beck/P. Brehm Chirurgie-Mechanik GmbH). The causes of the osteoarthritis varied. Hip replacement was carried out for the following conditions: rheumatoid arthritis including ankylosing spondylitis, aseptic necrosis of the femoral head, including posttraumatic and idiopathic forms, osteoarthritis of unknown origin, osteoarthritis following dysplasia or subluxation of the hips, and loosened cemented hip prostheses (131 primary implantations and 19 revisions). Full weight-bearing was not permitted for 50 days postoperatively, but mobilization and isometric exercises were started 2 days after operation and isotonic exercises were introduced later. Complications included fracture of the femoral shaft during operation and aseptic loosening. Our results in the 142 patients (150 joints) at 32-65 months (average 44 months) after surgery are encouraging. Good results based on patient satisfaction were obtained in 92.7% (81.3% after revision) and poor results in 7.3% (18.7% after revision). Most (90.2%) of the patients can walk without a stick (50.0% after revision), and 90.2% of the patients can walk more than 1000 m (68.8% after revision).