Metal release from hip prostheses: biological monitoring of cobalt and chromium in patients with metal-on-metal hip arthroplasty

The introduction of metal-on-metal implant components for hip replacement has the risk of heavy metals absorption and an increase in blood levels of metal ions, which may potentially lead to systemic toxicity. In the present study the concentration of Co and Cr were determined in the serum of patients with MoM arthroplasty in comparison with healthy subjects. This study assessed serum concentrations of Co and Cr in 134 patients having metal-on-metal (MoM) hip prosthesis. Control group consisted of 30 healthy individuals without MoM arthroplasty. Concentrations of Cr and Co were measured using an atomic absorption spectrophotometer. Data was statistically analyzed by ANOVA and multiple comparison tests were used to identify significant differences between groups (p < 0.05). Mean serum metal levels for patients were 4.6 mu g/L +/- 7.8 mu g/L for cobalt and 6.8 mu g/L +/- 9.4 mu g/L for chromium. In comparison with the control age matched group, we observed statistically significant differences p < 0.005. Mean serum levels for the control group were 0.77 +/- 0.19 mu g/L for cobalt and 0.51 +/- 0.23 mu g/L for chromium. No significant differences were observed based on gender or unilateral prostheses vs bilateral implants, although an upward trend was observed. The results suggests that the use of MoM hip prostheses led to an increase in the serum concentrations of Co and Cr, a potential indicator of ongoing Co and Cr exposure.