The Infection Rate of Metal-on-Metal Total Hip Replacement Is Higher When Compared to Other Bearing Surfaces as Documented by the Australian Orthopaedic Association National Joint Replacement Registry.

backgroundDespite the well-documented decline in the use of metal-on-metal (MoM) implants over the last decade, there are still controversies regarding whether all MoM implants are created equally. Complications such as elevated serum metal ion levels, aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL) and pseudotumours have all been well documented, but recent studies suggest increased risk of infection with MoM bearing surfaces. Most of these studies however have small patient numbers. QUESTIONS/PURPOSES: The purpose of this study was to examine the cumulative incidence of revision for infection of MoM bearing surfaces in primary hip arthroplasty at a national and single-surgeon level.

methodsData was collected from the Australian Orthopaedic Association National Joint Replacement Registry, which contains over 98% of all arthroplasties performed in Australia since 2001. The cumulative incidence of revision for infection was extracted at a national level and single-surgeon level.

resultsTwo hundred seventy-six thousand eight hundred seventy-eight subjects were documented in the Australian registry. The 10-year cumulative percent revision for infection of MoM bearing surfaces in primary total hip replacement (THR) was 2.5% at a national level, compared to 0.8% for other bearing surfaces. The senior author contributed 1755 subjects with 7-year follow-up and a cumulative percent revision for infection of MoM bearing surfaces in primary THR of 36.9%, compared to 2.0% for other bearing surfaces. The cumulative percent of revision of MoM bearing surfaces is higher compared to other bearing surfaces; this is especially pronounced in cumulative percent of revision for infection.

conclusionThere was a higher cumulative percent of revision for infection in MoM bearings surfaces (in particular, large-head MoM) compared to other bearing surfaces at both the national and individual-surgeon level.