Does the placenta inhibit the passage of chromium and cobalt after metal-on-metal total hip arthroplasty?

Umbilical cord serum and corresponding maternal serum of 3 women with uncemented metal-on-metal total hip arthroplasties were analyzed for cobalt and chromium. The women were an average 3.8 (range, 2–5) years after hip surgery. At the time of delivery, the maternal chromium concentrations were 1.6 μg/l, 0.5 μg/l, and 0.9 μg/l, respectively, and the maternal cobalt concentration was 1 μg/l in the first woman and below the detection limit in the other 2 women. Cobalt and chromium concentrations of the 3 umbilical cord sera also were below the detection limit. This indicates that—with regard to the detection limit of our laboratory—we were unable to observe a passage of cobalt and chromium ions from metal-on-metal articulations across the placenta at the time of delivery.