[Review of the results of the ARO multicenter study].

The ARO multicenter study intended to show clinical and radiological differences with regard to different systems of fixation and designs of the prothesis in total hip replacement in patients with hip dysplasia, osteoarthritis and rheumatoid arthritis. In 1987 and 1988 5255 total hip prothesis were implanted by the 24 hospitals which took part in the study. 3133 prothesis (95.6%) were clinically and radiologically examined. The follow-up period averaged 6.9 years. The results of the Aro multicenter-study showed that despite difficult preoperative conditions especially in cases of rheumatoid arthritis the satisfaction rate improved remarkably. During the operation less complications arose in comparison to patients with hip dysplasia and osteoarthritis. Regarding the rate of infection after operation there were no differences between the 3 groups. Only the rate of post-operative luxation concerning rheumatoid patients turned out to be twice the number of the others. In our opinion this is due to the fact that these rheumatics were operated by posterior approach. Patients with rheumatoid arthritis were satisfied most with their surgeries. Results of rheumatic patients according to Harris hip score were slightly worse than the results of the two other groups. This was due to systemic involvement and bad preoperative function of the hip. As a result of the study there were no differences in using cemented or cementless techniques for rheumatic hip replacement. The decision for the method of fixation should depend on the patient's ability to relief the prothesis after operation. The study has shown that cementless implantation can also be used for young rheumatics provided that a suitable design of prothesis will be selected.