Radiographic evaluation of midterm failure rates following metal-on-metal hip resurfacing.

This prospective study examined patient characteristics and radiographic findings for 89 subjects undergoing total hip resurfacing. Thirteen (14.6%) of 89 hips have required revision. Female sex, smaller implant size, and diagnosis of osteonecrosis were associated with lower device survival. No significant differences in acetabular cup angle and stem angle were observed between revised and nonrevised hips. Revision rates for the first 25 hips were 24% and 8% for the last 64 hips. Females accounted for 56% of subjects 1 to 25 and 23% of subjects 26 to 89. Despite representing only 33% of included subjects, females accounted for 62% of revision procedures. The lower device survival proportion in subjects 1 to 25 could not be attributed to acetabular or femoral component malpositioning and can likely be explained by a significantly higher proportion of females enrolled early in the study.