NEOPLASTIC TRANSFORMATION OF CELLS BY SOLUBLE BUT NOT PARTICULATE FORMS OF METALS USED IN ORTHOPEDIC IMPLANTS

Recent developments in cell culture techniques have made it possible t o study the cellular mechanisms involved in carcinogenesis and to appl y these methods as screening tools in vitro. This study investigated a nd compared the ability of the metals most commonly used in orthopedic implants to induce toxicity and neoplastic transformation in the C3H1 0T1/2 mouse fibroblast cell line. Eight metals (cobalt, chromium, nick el, iron, molybdenum, aluminium, vanadium and titanium) and their allo ys (stainless steel, cobalt-chrome alloy and titanium alloy) were test ed, both as soluble salts and as solid particles. There were marked di fferences between the various metals in terms of both toxicity and tra nsforming ability. Significant increases in the incidence of cell tran sformation were seen with soluble forms of cobalt, chromium, nickel an d molybdenum but not with iron, aluminium, vanadium or titanium. For m ost of the metals, transforming ability was directly related to toxici ty, although this correlation did not hold for either molybdenum or va nadium. The physical form of the metal was critically important in det ermining its effects, and transformation occurred only with soluble me tal salts. (C) 1998 Elsevier Science Ltd. All rights reserved.