Inferior outcome after hip resurfacing arthroplasty than after conventional arthroplasty

Methods The risk of non-septic revision within 2 years was analyzed in 1,638 HRAs and compared to that for 172,554 conventional total hip arthroplasties (THAs), using Cox regression models. We calculated relative risk (RR) of revision and 95% confidence interval. Results HRA had an almost 3-fold increased revision risk compared to THA (RR = 2.7, 95% CI: 1.9-3.7). The difference was even greater when HRA was compared to the THA subgroup of cemented THAs (RR = 3.8, CI: 2.7-5.3). For men below 50 years of age, this difference was less pronounced (HRA vs. THA: RR = 1.9, CI: 1.0-3.9; HRA vs. cemented THA: RR = 2.4, CI: 1.1-5.3), but it was even more pronounced in women of the same age group (HRA vs. THA: RR = 4.7, CI: 2.6-8.5; HRA vs. cemented THA: RR = 7.4, CI: 3.7-15). Within the HRA group, risk of non-septic revision was reduced in hospitals performing >= 70 HRAs annually (RR = 0.3, CI: 0.1-0.7) and with use of Birmingham hip resurfacing (BHR) rather than the other designs as a group (RR = 0.3, CI: 0.1-0.7). Risk of early revision was also reduced in males (RR = 0.5, CI: 0.2-0.9). The femoral head diameter alone had no statistically significant influence on the early revision rate, but it eliminated the significance of male sex in a combined analysis. Interpretation In general, our results do not support continued use of hip resurfacing arthroplasty. Men had a lower early revision rate, which was still higher than observed for all-cemented hips. Further follow-up is necessary to determine whether HRA might be useful as an alternative in males.