Subcapital Femoral Fracture with Cephalomedullary Nail Lag Screw Failure after Healed Intertrochanteric Fracture: A Case Report.

Introduction: Intertrochanteric fractures are very common injuries in the elderly population and are typically managed with cephalomedullary nailing. Even though this approach generally has successful outcomes, complications like implant failure or peri-implant fractures could still occur, especially in osteoporotic patients. Case Presentation: An 87-year-old female with a previously operated intertrochanteric femoral fracture presented with a subcapital femoral neck fracture combined with breakage of the cephalic lag screw. Imaging showed no signs of non-union or malalignment in the pertrochanteric region. Management: The patient underwent cemented dual mobility total hip arthroplasty after removal of the broken lag screw and cephalomedullary nail. Intraoperatively, a distal femoral spiral fracture occurred. This was stabilized with lag screws and a locking plate. The patient recovered uneventfully and returned to full weight-bearing 3 months postoperatively. Conclusion: This case highlights a rare complication and presents a therapeutic approach in the context of contemporary literature.