Carcinogenicity and metallic implants.

The literature related to the carcinogenetic potential of metallic implants was reviewed. There were 20 cases described in which tumors were identified in proximity to metallic implants. These cases occurred over a 34-year period. Investigators have identified a 70% increased incidence of lymphomas and hematopoietic tumors over that in the general population in patients who had received total hip arthroplasties. Carcinogenicity theories include the potential direct toxicity of materials, the effects of surface properties, the electromotive potential created by dissimilar metals in contact, the immunologic response to implants, and finally, the sustained presence of low-grade infection. Corrosion is a well-documented phenomenon and occurs with any type of metal. The rate of formation of corrosion products and their toxicity varies with the implant composition. Toxic effects of metals, such as malignant potential and other adverse effects, have been demonstrated in animal models. The published information on this controversial and very poignant issue of metallic carcinogenesis is useful for all orthopedic surgeons.