Extensive osteolysis around an aseptic, stable, uncemented total knee replacement.

Extensive osteolysis occurred around an aseptic, well-fixed, stable, uncemented total knee prosthesis. At the time of revision, tibial polyethylene wear and minimal metal-on-metal contact were present. A hypertrophic synovium-like membrane abutted bone in regions of osteolysis. Examination of this membrane revealed polyethylene-wear debris and significant levels of chromium, cobalt, and titanium. Wear debris--polyethylene, metal, or a combination of both--may be responsible for the osteolytic process in this case.