Metal presence in hair after metal‐on‐metal resurfacing arthroplasty

The elevation of metal levels in serum and urine during post‐operative follow‐up is a frequent find following the implantation of certain models of metal‐on‐metal hip prostheses. Among 45 patients with the same resurfacing prostheses, chromium (Cr) and cobalt (Co) levels in serum and urine were determined at 3, 4, 5, and 6 years after surgery. In the same period, levels of Cr, Co and molibdene (Mo) in scalp hair were also measured. Mean Cr and Co levels in serum were 8.29 µg/L (SD 17.97) and 8.38 µg/L (SD 21.97), respectively, whereas in urine levels were 16.20 µg/L (SD SD 32.55) and 75.40 µg/L (SD 190.86), respectively. In hair, mean Cr level were 163.27 µg/g (SD 300.62), mean Co level 61.98 µg/g (SD 126.48), and Mo 31.36 µg/g (SD 37.86). A high concordance was observed between chromium‐urine and chromium‐serum and between cobalt‐urine and cobalt‐hair. A moderate concordance was present between cobalt‐urine and cobalt‐serum, and between cobalt‐hair and cobalt‐serum. Eleven patients required revision surgery, five of them due to metallosis and periarticular cyst. At 1 year after reintervention, analytics were performed again and the following decrease rates were found: 42.8% in Cr levels, 51.1% in Mo levels, and 90.3% in Co levels.