Revision Total Hip Arthroplasty Using an Acetabular Reinforcement Ring With a Hook: A Precise Follow-Up, at Average 11.4 Years, of a Previous Report

BACKGROUND: This study aims at determining the average long-term result of revision total hip arthroplasty (THA) using the acetabular reinforcement ring with a hook (ARRH) and bone grafting in severe acetabular bony defect. Expected 15-year survival of ARRH in revision THA is included in the study.

METHODS: Retrospective review of 48 patients (48 hips) with follow-up duration of average 11.4 years (range, 6.1-21.4 years) was conducted. At each follow-up, Harris hip score was used to assess functional outcome, and radiographic acetabular component osteolysis was measured by DeLee and Charnley classification. Bone defects were assessed preoperatively and intraoperatively using American academy of orthopedic surgeons and Paprosky classification. The common modes of ARRH failures were evaluated. Bone consolidation, presence of heterotopic ossification, and complications such as infection and dislocation were recorded.

RESULTS: The bone defects were varied and included cavitary, segmental, and combined defects without any pelvic discontinuity. Mean Harris hip score improved from 52.6 points preoperatively to 82.0 points postoperatively. Nine acetabular revisions and 3 stem revisions (2 concurrent with acetabular revisions and 1 isolated stem revision) were performed. There were 5 infected cases and 1 patient with recurrent dislocation. The 11.4-year survival of revision THA with ARRH was 71% as the end point for acetabular revision surgery for any reason. The expected 15-year survival of revision THA with ARRH was 60%. The most common failure mode of ARRH was superomedial migration followed by lateral migration.

CONCLUSION: ARRH combined with bone grafting produces relatively good average long-term clinical results.