STP859: Biological Effects of Corrosion Products from Metals

    Merritt, K
    Associate professors of Biomedical Engineering, Case Western Reserve University, Cleveland, OH

    Brown, SA
    Associate professors of Biomedical Engineering, Case Western Reserve University, Cleveland, OH

    Pages: 13    Published: Jan 1985


    Abstract

    Metallic implants inserted into the body will eventually undergo some degradation by a variety of mechanisms including abrasion and corrosion. The biological effects of the material released into the tissue is a subject of much concern and investigation. We have been investigating the ability of the metallic implants upon degradation to stimulate metal sensitivity reactions, and studies have been undertaken in humans and animals to investigate the tissue response to metallic implants in the presence of metal sensitivity. It is apparent that many patients have a sensitivity to the metals in the implants and that the presence of metals in a sensitive animal or human will elicit inflammatory responses and sometimes the formation of foreign body giant cells. This may have an adverse effect on the performance of the implant with pain, swelling, and tissue necrosis at the site and, in some cases, loosening of the implant. Studies on implant site infections revealed that infection rates are altered by the presence of this tissue response.

    Metal sensitivity reactions are not to the small metal ions but to a complex of metal ions and host tissue. The nature of the binding of the metal ion to tissue or cells, the distribution of the metal ion or metal complexes in the body, and the biological responses to these complexes are of concern. We have undertaken in vitro and in vivo studies on the binding of metal ions as metal salts or as corrosion products, and it is evident that metals bind mostly to albumin. The ability of these different metals to bind to red cells and white cells varies with chromium with a valence of 6+ binding most strongly to cells. The chrome from corrosion products binds strongly to cells and thus appears to be a chromium 6+.

    Metal salts or corrosion products injected intramuscularly are rapidly distributed in the body with cell binding again being seen mostly with chromium 6+. Cobalt is not distributed as rapidly in the body and apparently binds to the tissue at the site of the intramuscular injection. The interaction of serum and cells with chromium on the surface of the implant may markedly effect its corrosion and the biological activity of the complexes formed. Some of the tissue and protein binding may be altered by shifts in the pH in the tissue during inflammatory responses or in infection.

    Keywords:

    stainless steels, metal sensitivity, metal-protein complexes, metal-cell complexes, sensitivity, infection, corrosion, implant materials, biological degradation


    Paper ID: STP33253S

    Committee/Subcommittee: F04.19

    DOI: 10.1520/STP33253S


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