[Murata-Chiba (MC) support ring for acetabular defect in rheumatoid hip].

Acetabular protrusion presents a particular challenge in rheumatoid arthritis. Our surgical plan is (1) to use autologous bone grafts for reconstruction of the acetabulum (2) to locate the correct anatomic position of the acetabulum, (3) to use a uncemented porous socket with rigid screw fixation. From 1991 we began to use MC (Murata-Chiba) support ring which was assembled with Harris-Galante porous socket for highly deformed hip such as acetabular protrusion. We evaluated the clinical and radiographic results of 10 cases. All cases had excellent or good results at follow-up with improved overall function in terms of standing, transfer activities and relief of pain. No apparent complications related to the device was noted. MC support ring is an useful device in rheumatoid hip with severe acetabular protrusion.