Hip Fusion Takedown with Dislocation and Cup Dislodgement Requiring Revision Arthroplasty: A Case Report

Introduction: Spontaneous hip fusion is a multifactorial condition that can cause drastic functional limitations. Total hip arthroplasty (THA) can provide symptomatic improvement but leads to high rates of instability, dislocation, and revision. Case Report: A 66-year-old woman with a long-standing history of dysplastic and spontaneously fused left hip received a fusion takedown to primary THA. She subsequently dislocated with catastrophic acetabular cup failure necessitating revision THA. She reports no pain or dislocations at 12 months post-revision. Conclusion: Deciding to perform THA for spontaneous hip fusion should consider clinical benefit alongside increased risks of dislocation and revision. Patients with acetabular dysplasia and longer durations of fusion are at an increased risk, due to skewed anatomic landmarks, weak abductors, and altered spinopelvic parameters. However, in the case of primary THA failure, revision surgery can provide satisfactory benefits. Keywords:Hip fusion, hip arthrodesis, hip fusion takedown, total hip arthroplasty, hip dislocation.