engleski

Analysis of cobalt and chromium in blood fractions of patients with hip implants

In some patients with metal-on-metal hip implant systems, particularly when cast molded Cr-Co alloys were used, the joints wear increase debris formation to a significant level. Increased circulating metal ions could reach high levels in blood and serum and therefore adversely affect patient's health. We assessed Co and Cr status in 20 patients after hip arthroplasty (aged 63±11.4 years ; >1 year after operation). To estimate the most appropriate biomarker of Co and Cr status, we analyzed levels of Co and Cr in different blood fractions (whole blood, serum and erythrocytes) using ICP-MS. Median and range blood, serum and erythrocyte Co levels were 1.38 (0.21-134) ; 1.53 (0.21-113, and 0.46 (0.09-50.9) mug/L of blood, while Cr levels were 2.05 (0.74-42.1), 2.64 (0.76-68.6), and 0.55 (0.33-1.34) mug/l of blood. Concentrations of the metal between blood fractions were highly correlated (r=0.83-0.99 ; p<0.001). The results have shown that Co is distributed equally between plasma and red blood cells, while Cr ions are in very low concentrations in red blood cells. As only highly toxic Cr(IV) form crosses cell membranes easily, our results suggest rather Cr(III) than Cr(VI) exposure in patients with Cr-alloy hip implants. Both serum and whole blood could be used for assessment of Co and Cr status and metal wear debris rate formation in patients with metal-on-metal hip implants. However, because of dominant Cr distribution in serum and easier measurements using simpler matrix, serum might serve as a better indicator of the true metal status and implant failure.

erythrocytes; ICP-MS; levels of Co and Cr; metal-on-metal hip implants; serum; whole blood

Poster presentation P-19