A NEW TECHNIQUE FOR QUANTITATION OF METAL PARTICULATES AND METAL REACTION-PRODUCTS IN TISSUES NEAR IMPLANTS

Tissue specimens retrieved from four regions adjacent to hip implants during revision surgery were subjected to a novel treatment to make po ssible the quantitative separation of residual metal particulates and metal reaction products (metal ions and metal-protein complexes). The tissues were exposed to sodium hypochlorite solution that degraded and solubilized them, liberating metal reaction products and leaving behi nd metal wear particles, which were separated by centrifugation. Atomi c absorption spectrophotometry was used to analyze the concentrations of the separated metal ions and wear particles. Co ion concentrations were 0.05 to 0.9 mM, Cr ion concentrations were 0.04 to 2.1 mM, and Ti ion concentrations were 0.30 to 0.60 mM. The weight of Co metal parti cles was 0.1 to 4.9 mg/100 mg tissue, of Cr metal particles 0.07 to 2. 2 mg/100 mg tissue, and of Ti particles 0.09 to 5.2 mg/100 mg tissue; one black tissue sample contained 3333 mg Ti/100 mg tissue. No correla tion was found between the concentrations of these two entities in the samples examined, probably due to the complex and varied processes cr eating them. The procedures discussed here will result in data that ca n help elucidate the separate contributions of metal reaction products and metal particulates to implant loosening. (C) 1994 John Wiley & So ns,Inc.