Hip fusion takedown to a total hip arthroplasty—is it worth it? A systematic review

Introduction Patients with surgically or spontaneously fused hips are often dissatisfied with their overall function and the debilitating effect on adjacent joints. Therefore, in properly selected patients, hip fusion-takedown and conversion to total hip arthroplasty (THA) can result in improved function and decreased pain. We aimed to (1) evaluate the indications for conversion, (2) evaluate the clinical outcomes, (3) analyze the overall complications, and (4) identify the overall satisfaction following the procedure. Methods A systematic and comprehensive literature search was performed to analyze studies evaluating conversion of hip fusion to THA. After reviewing 3,882 studies, 27 total studies (1,104 hips) met our inclusion/exclusion criteria and were included in our final analysis. A weighted mean of rates was determined for each complication, including infection, instability, loosening, nerve-related, abductor-related, venous thrombotic event, and revision. Results The study population consisted of 53.2% male and 46.8% female subjects. The mean age at time of conversion was 52 years (range 36–65 years), the mean time until follow-up was 9.2 years (range 2.5–17.3), and the mean duration of arthrodesis was 27.7 years (range 11–40.2). As measured by Harris Hip Score, overall clinical outcomes improved from 58.1 points (range 42.4–70 points) pre-operatively to 80.0 (range 62–93.5) post-operatively. The specific complication rates were 5.3% (range 0–43.6%) for infection, 2.6% (range 0–15.4%) for instability, 6.2% (range 0–17.2%) for loosening, 4.7% (range 0–13%) for nerve-related complications, 13.1% (range 0–87%) for abductor-related complications, and 1.2% (range 0–13%) for venous thrombotic events. The revision rate was 12.0% (range 0–43.6%). Conclusion Takedown of a fused-hip can be a challenging procedure. Although patients can benefit functionally, both patients and surgeons need to be aware of the complications and increased risk of further revision procedures, which should be an important part of the pre-operative discussion.