Lainiala O, et al. - This study investigated the association between glomerular filtration rate (GFR) and blood cobalt (Co) and chromium (Cr) levels in patients with metal-on-metal (MoM) hip arthroplasty. No link was observed between GFR and blood metal ion levels. Consequently, the accumulation of Co and Cr in blood due to renal insufficiency did not appear to be a major risk in patients with mild or moderate renal insufficiency.