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).