[Hypersensitivity to metals in patients with orthopedic implants]

All metals in contact with biological systems suffer corrosion, which is an electrochemical process that causes metallic ions formation, known as haptens, which link with endogenous or exogenous proteins, therefore inducing an immune response. A hypersensitivity response to an implanted material should be suspected when cutaneous lesions or inflammatory reactions occur proximal to or surrounding the site of the metallic orthopedic implant. At present there is no a reliable diagnostic test for the determination of hypersensitivity to implanted metallic devices. It has been shown that the products of corrosive degradation are associated with dermatitis, urticaria and vasculitis. Cutaneous lesions in patients with unsuccessful metallic implants are more frequent than in non-rejected implants or the general population. Although the cellular and humoral hypersensitivity response in metallic orthopedic implants has been clearly identified, the risk is very low. Nowadays the importance of hypersensitivity to metals as a contributing factor in the failure of implants is unknown.