Staged total hip arthroplasty in a patient with hip dysplasia and a large pertrochanteric bone cyst.

Hip arthroplasty in young patients requires thoughtful preoperative planning. Patients with proximal femoral bone loss complicate this planning and may require a staged procedure to optimize implant insertion. We report on a case of a 26-year-old woman with secondary hip arthritis from developmental dysplasia of the hip and a large pertrochanteric bone cyst that was treated with staged total hip arthroplasty. The cyst was decompressed and filled with an osteoconductive and osteoinductive bone graft substitute called EquivaBone. One year later, the patient underwent a successful primary total hip arthroplasty. Fifteen-month follow-up after her hip replacement revealed resolution of postoperative pain and significant functional improvement.