Modular femoral stem-sleeve junction failure after primary total hip arthroplasty

The total hip prosthesis has evolved from the initial monoblock system developed by Charnley. Modularity of both the femoral and acetabular components, which allows the surgeon to assemble the prostheses just before or during the course of implantation, has now become standard. Modularity increases the number of implant parameter variables, allowing semicustom devices to be constructed. Component interfaces, however, are subject to significant stresses, micromotion manifesting as fretting, may produce wear debris, and at times may experience macromotion leading to catastrophic failure. We report 3 cases of stem-sleeve junction failure in otherwise uncomplicated primary total hip arthroplasties. Two of the failures occurred in the S-ROM (Joint Medical Products, Stamford, Conn) femoral stem design and the other in an Apex stem (Omni Life Science, Raynham, Mass). To our knowledge, there have been no previous reports of clinical failures at femoral stem-sleeve junction.