1. A patient with a Vitallium hinged knee prosthesis studied at autopsy forty-two months after implantation was presented.
2. Clinically, the patient had no complications or clinical evidence of tissue reaction while receiving good, pain-free service from the prosthesis.
3. Pathologically, a massive amount of Prussian blue positive staining material was found in the capsule and lining the canals formed by the stems of the prosthesis.
4. Mechanical wear (corrosion) was evident at the areas of contact and on the central axis of the hinge.
5. The importance of mechanical design and composition is seen to be a significant consideration of reconstructive surgery.