Paraneoplastic Clostridium septicum infection of a total knee arthroplasty.

We describe a case of a well-functioning total knee arthroplasty acutely infected with Clostridium septicum. This is the first reported infection of a prosthetic joint with this organism. A search for the source of this infection uncovered a colonic malignancy. This organism is highly associated with gastrointestinal malignancy, and appropriate investigation should be carried out when it is discovered. The importance of full anaerobic bacterial identification by the microbiology laboratory is underscored by this case.

Posterior condyle surface damage on retrieved femoral knee components.

Twenty-two retrieved femoral knee components were identified with posterior condyle surface damage on average at 99° flexion (range, 43°-135° flexion). Titanium alloy material transfer and abrasive surface damage were evident on cobalt-chromium alloy femoral components that were in contact with titanium alloy tibial trays. Surface damage on the retrieved Oxinium femoral components (Smith and Nephew, Inc, Memphis, Tenn) that were in contact with titanium alloy tibial trays showed gouging, associated with the removal and cracking of the oxide and exposure of the zirconium-niobium alloy substrate. Cobalt-chromium alloy femoral components that were in contact with cobalt-chromium alloy tibial trays showed abrasive wear. Contact between the femoral component and tibial tray should be avoided to prevent surface damage to the femoral condyles, which could potentially accelerate polyethylene wear in vivo.