Malignant neoplasms associated with orthopedic implant materials in rats

The carcinogenic potential of 22 orthopedic prosthetic materials was studied by implantation in bone in Sprague-Dawley rats and evaluated by complete autopsy examination performed at the time of death or at the end of the 30 month experimental period. When the number of malignancies in these rats was compared with control and sham-operated animals, a small increase in sarcomata was observed in animals bearing metal alloy implants containing high contents of cobalt, chromium, or nickel. An increased incidence of lymphomata with bone involvement was also observed in rats bearing metal implants when compared with control and sham-operated animals.