Premature failure of a hip hemiarthroplasty secondary to osteolysis and aseptic loosening.

摘要

Bipolar hemiarthroplasty and unipolar hemiarthroplasty have been widely used, especially in cases of femoral neck fracture in elderly patients. In this article, we report on a single case of premature loosening of a bipolar endoprosthesis secondary to presence of titanium and polyethylene debris from wear. We removed the patient's prosthesis and performed a total hip arthroplasty. With use of improved surgical and cementing techniques, state-of-the-art biomaterials, and better patient selection, hemiarthroplasties recently became as long-lived a stotal hip arthroplasties. However, our patient's case of premature loosening points up some basic principles regarding the tribology of implant failure: First, the surface of titanium is poor for articulation; second, polyethylene wear, especially in cases of bipolar hemiarthroplasty with a thin liner and in the presence of titanium prostheses, may hasten failure; third, meticulous third-generation cementing techniques minimize the risk for premature failure; and fourth, hemiarthroplasties performed in patients with previous surgery have higher rates of premature failure.