Sister chromatid exchanges and ion release in patients wearing fracture fixation devices

The quantification of sister chromatid exchange (SCE) during mitosis is a u seful index for evaluating genotoxic effects in subjects occupationally or incidentally exposed to potentially toxic substances. The authors investiga ted the hypothesis that ions released by corrosion from prosthetic componen ts of fracture fixation devices are associated with change in SCE incidence . In the present study, ten patients with implants were examined, and fifte en subjects with no implants were used as controls. SCE and high frequency cell (HFC) numbers were evaluated in circulating lymphocytes. Ln addition, nickel (Ni) and chromium (Cr) ion values in the serum were measured because , after iron, these metals are major components of stainless steel. A signi ficant increase in SCE numbers was observed in patients compared to the con trol population (4.9 +/- 1.3 vs. 3.5 +/- 1.4). Ni concentration was 1.71 +/ - 1.49 ng/mL in patients and 0.72 +/- 0.52 ng/mL in control subjects; Cr co ncentration was, respectively, 1.01 +/- 0.77 ng/mL and 0.19 +/- 0.27 ng/mL. The increase of serum Cr and Ni was statistically significant. No correlat ion was found between the increased Cr concentrations and SCE number while Cr ion levels were found to be significantly correlated to HFC. An inverse correlation between Ni level and SCE numbers was observed. Our findings sug gest that Cr release by stainless steel implants could have a genotoxic eff ect; thus it would be useful to carefully monitor implanted subjects with r egard to serum ion dosage, SCE analysis, and HFC evaluation. In any case, i t would be appropriate to remove the implant when fracture fixation is reac hed. (C) 2000 John Wiley & Sons, Inc.