Low dislocation rate following revision total hip arthroplasty (THA) with dual mobility cup with minimum 2-year follow-up.

Abstract

Dislocation is the second most common indication for revision total hip arthroplasty (THA). In revision cases the dislocation rate can be as high as 5-30%. The aim of this study was to assess the outcome, specifically the dislocation rate in revision THA where a dual mobility cup was used. We retrospectively reviewed all the revision THAs where a dual mobility cup (G7) was used. The pre-operative and post-operative oxford hip scores were recorded. Patients' electronic records and radiographs were studied for the indications, approaches used, post-operative complications, re-operation rates, and re-revision surgery. Between 2016 and 2020, we performed 59 revision total hip replacements where a dual mobility cup (G7) was used. There were 23 males and 36 females. The average age was 74 years (range, 64-89). Acetabular components were revised in 47 (80%) cases and both the femoral and the acetabular components were revised in 12 (20%) cases. The average follow-up time was 4 years (range, 2-6 years). Average pre-operative and post-operative oxford hip scores were 17 and 36 respectively. The improvement was significant with P value of <.001. Complications were noted in 5 (8%) patients. One patient had dislocation. This patient required re-revision with constrained liner. One patient had intraoperative fracture of the femur and was treated with plate and cables. We conclude that the dual mobility cup can significantly reduce the risk of dislocation when used in revision THA.