ABSTRACT
Metals are used as biomaterials because of their excellent electrical and thermal conductivity and mechanical properties. Some metallic alloys are used for more active roles in devices such as vascular stents, catheter guide wires, orthodontic archwires, and cochlea implants. Most metals such as iron, chromium, cobalt, nickel, titanium, tantalum, niobium, molybdenum, and tungsten that were used to make alloys for manufacturing implants can only be tolerated by the body in minute amounts. Since the metallic bond is essentially nondirectional, the position of the metal ions can be altered without destroying the crystal structure resulting in a plastically deformable solid. Histological examination of the stained so tissue showed “brin necrotic debris” and collagenous, fibrous tissue containing a histiocytic and foreign body giant cell infiltrate. The metallosis, black staining of the periprosthetic tissues, has been implicated in knee implant.
