In Vivo Wear Rate of the Birmingham Hip Resurfacing Arthroplasty: A Review of 10 Retrieved Components

The wear of 8 femoral and 2 acetabular components of the Birmingham Hip Resurfacing (Midland Medical Technologies Ltd, Birmingham, UK) was measured using a coordinate measuring machine (CMM5; SIP, Geneva, Switzerland). After a median in situ time of 13 months, measurements of the Birmingham Hip Resurfacing femoral heads revealed a median volumetric wear of 2.9 mm³. In one case with a cup abduction angle of 70°, a significantly higher wear of 17.8 mm³ was found. The 2 acetabular components showed volumetric wear of 5.4 and 27.6 mm³ after 14 and 15 months in vivo. The wear rates of the investigated femoral components were somewhat, but not significantly, higher than the previously investigated 28-mm Metasul heads (median, 0.8 mm³; Zimmer GmbH, Winterthur, Switzerland).