The action of cobalt, nickel and chromium on phagocytosis and bacterial killing by human polymorphonuclear leucocytes; its relevance to infection after total joint arthroplasty.

Infection after total joint arthroplasty is a serious clinical complication. The accumulation of metallic wear and corrosion products may cause a localized reduction in the defense process, which may be particularly relevant in the cause of late infections. This hypothesis has been tested by exposing human polymorphonuclear leucocytes (PMN) in vitro to cobalt, nickel and chromium at various concentrations. The ability of PMNs to phagocytose and kill Staphylococcus epidermidis was measured. Nickel and cobalt reduced the number of bacteria phagocytosed by about 50% at a concentration of 0.05 and 0.01 mumol ml-1 respectively over an 18 h incubation period. Neither metal affected the rate at which S. epidermidis was killed. Chromium had no effect. All metals were used at sub-toxic levels.