The metal-on-metal large-diameter-head (MoM-LDH) hip replacements increased in popularity during the start of the 21st century. Subsequently reports raised concerns regarding adverse reactions due to elevated chromium (Cr) and cobalt (Co) concentrations as well as high rates of other complications and revisions.~This was a single center parallel-group randomized controlled trial. The primary outcome was to compare Cr and Co concentrations at 5-years follow up following MoM-LDH total hip arthroplasty (MoM-LDH-THA) or MoM-LDH hip resurfacing (MoM-LDH-HR).~Secondary outcomes were radiological findings, patient reported outcome measures and revision rate at 5-years follow up.~The study was prematurely terminated in 2012 due to alerts and safety communications from the Danish national regulatory agency regarding early failure rates and high incidence of ARMD in patients with MoM hip implants [13]. At that time the study population consisted of 75 patients out of 200 planned for inclusion.
The investigators aimed to investigate the possible differences in metal ion concentrations in patients following one of two types of metal-on-metal articulating hip prosthesis regarding chromium and cobalt concentration, radiological findings, patient reported outcome measures and rate of revision at 5-years follow up.