Publication:

Stem-retaining conversion to total hip arthroplasty after dissociation of a cemented fixed bipolar hemiarthroplasty following failed closed reduction

Dislocation after bipolar hemiarthroplasty is a known complication, but dissociation of a fixed (non-modular) cemented bipolar prosthesis during attempted closed reduction is extremely rare. Standard management usually requires stem removal and revision total hip arthroplasty (THA), often necessitating extended trochanteric osteotomy (ETO), which increases morbidity in elderly patients. A 78-year-old male underwent cemented bipolar hemiarthroplasty for fracture neck of femur. Following a fall, he presented with painful hip deformity and inability to bear weight. Closed reduction attempted elsewhere failed and resulted in dissociation of the bipolar prosthesis, with separation of the outer cup from the femoral head. Radiographs confirmed dissociation with the stem well fixed in cement mantle. Considering advanced age and stable cemented stem, a stem-retaining conversion THA was planned. Previous operative records revealed a 32-mm head on a 10–12 mm taper. The acetabulum was prepared and a cemented polyethylene acetabular component implanted. Without removing the cemented stem or performing extended trochanteric osteotomy, the hip was reduced using a compatible femoral head. Stable reduction and satisfactory range of motion were achieved intraoperatively. Post-operative radiographs showed well-positioned acetabular component and stable hip joint. The patient was mobilized with walker support. At follow-up, the patient was ambulatory, pain significantly reduced, and no redislocation occurred. Stem-retaining conversion THA is a viable and less invasive salvage option in selected elderly patients with dissociated bipolar hemiarthroplasty when the cemented femoral stem is stable. This technique avoids extended trochanteric osteotomy and reduces surgical morbidity.