Favorable outcome of total hip arthroplasty with insufficient bone coverage of the roof reinforcement ring: a case report

A 59-year-old male patient underwent a total hip arthroplasty for the treatment of end-stage dysplastic osteoarthritis. A roof reinforcement ring, a cemented polyethylene cup, and a cementless stem were used. Extensive superolateral portion of the ring was uncovered by host bone. Morsellized autogenous femoral-head graft was impacted to fill the space between superolateral border of the ring and superior part of the dysplastic acetabulum. At the follow-up after 4-years, the patient had no complaints and was very satisfied with the operation result. The hip radiograph revealed no signs of instability of the acetabular component, and no bone graft resorption. Despite the suboptimal implantation of the ring compromising, apparently, mechanical stability of the prosthesis, the outcome was favorable. This result can be supported by the fixation of the metal ring with screws, the adequate orientation of the prosthesis, the position of hip´s center of rotation, and bone graft incorporation