Beschreibung:
<jats:sec><jats:title>Purpose</jats:title><jats:p> To determine whether gender, femoral head size, acetabular inclination, and time since surgery predicted high blood metal ion concentrations following Birmingham Hip Resurfacing (BHR). </jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p> BHR patients with unilateral bearings at one specialist centre with blood cobalt and chromium concentrations measured up to May 2013 were included. This comprised a mixed (at-risk) group including symptomatic patients and asymptomatic individuals with specific clinical and/or radiological findings. Blood sampling was at a mean of 7.5 years (range 1-15.4 years) postoperatively. </jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p> Of 319 patients (mean age 49.3 years; 53% male), blood metal ions greater than 7 µg/l were observed in 9% (n = 28). Blood metal ions were significantly higher in females (p<0.001), femoral head sizes ≤48 mm (p<0.01), and cup inclinations >55° (p<0.001). Linear regression demonstrated femoral head size was responsible for the highest proportion of variance in blood metal ions (cobalt p<0.001, R<jats:sup>2</jats:sup> = 8%; chromium p<0.001, R<jats:sup>2</jats:sup> = 11%). Analysis of femoral head size and inclination together demonstrated 36% of BHRs with head sizes of 38-44 mm and inclination >55° had blood metal ions >7 µg/l. BHR 10-year survival for this at-risk group was 91% (95% confidence intervals 86.0%-95.0%) with 30 hips revised. </jats:p></jats:sec><jats:sec><jats:title>Conclusions</jats:title><jats:p> If blood metal ions are used to screen hip resurfacing patients for adverse reactions to metal debris it is recommended those with small femoral head sizes (38-44 mm) and high acetabular inclinations (>55°) are targeted. These findings require validation in other cohorts as they may not be applicable to all hip resurfacing devices given the differences in radial clearance, coverage arc, and metallurgy. </jats:p></jats:sec>