Acetabular roof reinforcement rings.

A series of 30 total hip arthroplasties was performed in 29 patients with the use of the Mueller roof reinforcement ring (RRR). The mean follow-up observation time was 30 months (standard deviation [SD] = 7.6). The clinical and radiologic results were evaluated according to the Mayo Clinic scoring system. The overall preoperative clinical score of 21.963 (SD = 18.776) points improved to a follow-up examination score of 69.533 (SD = 11.599), a correction of 68.41%. The authors' goal in this series was to implant the ring together with the polyethylene socket as close to the anatomic position of the acetabulum as possible. There was no loosening of the RRR or the polyethylene sockets, nor was there material failure in the last evaluation of the hips. No statistically significant difference was found when the differences between the follow-up scores of the primary versus the revisionary procedures were compared. The roof replacement ring has been helpful for primary and revision arthroplasties of acetabular deficiencies occurring within five years after operation.