A Multinational Assessment of Metal-on-Metal Bearings in Hip Replacement
Stephen Graves, Alastair Rothwell, Keith Tucker, Joshua Jacobs, Art Sedrakyan
Abstract: There is emerging evidence that many metal-on-metal
(MoM) bearings, when used with large femoral heads
in conventional hip replacement and some resurfacing
prostheses, are associated with increased rates of revision
Registries are the main sources of data on MoM prostheses. At the recent International Consortium of Orthopaedic Registries (ICOR) meeting, data were presented from the Australian, England and Wales, and New Zealand registries. All
registries reported an increased rate of revision for large femoral head MoM prostheses when prostheses were aggregated compared with the aggregated data of hip prostheses with other bearing surfaces. There was also evidence, however, that the outcome varied, depending on the type of prostheses used, in both large femoral head MoM conventional hip replacement as well as resurfacing hip replacement.
The relevance of the recent isolated case reports on systemic metal toxicity was also discussed at the ICOR meeting.
Although systemicmetal toxicity appears to be a rare occurrence, there is a need to undertake appropriately designed studies to define the true prevalence of this phenomenon. There may be advantages in nesting these studies within registries. The ICOR meeting highlighted the implications of the MoM experience for the orthopaedic industry, regulators, and surgeons.