Serum cobalt and chromium elevations following hip resurfacing with the Cormet 2000 device

This study was designed to monitor serum cobalt (Co) and chromium (Cr) levels at multiple time points following hip resurfacing with the Cormet 2000 device. Serum samples were obtained preoperatively, at 6 months, 1, 2, and 3 years after surgery. Co/Cr levels (micro g/L) were determined by high-resolution inductively coupled plasma mass spectrometry. Thirty-five subjects were followed. Median preoperative Co/Cr levels were 0.21 and 0.22, respectively. Serum levels following device implantation were increased at all follow-up time points when compared to preoperative controls. Peak levels were observed at 1 year (Co, 3.34; Cr, 4.67) and levels at 3 years were trending down (Co, 2.08; Cr, 3.55), but this decrease was not statistically significant. This study is the first to report significant elevations in serum Co/Cr levels at multiple time points up to 3 years following hip resurfacing with the Cormet 2000 device. Future studies are needed to determine what serum Co/Cr levels are of clinical concern, particularly in outlier cases.