Birmingham Hip Resurfacing for osteoarthritis - a Canadian retrospective cohort study with a minimum 10-year follow-up

Background: Young men with osteoarthritis of the hip are a growing segment of the population requiring arthroplasty, and there is compelling evidence that the Birmingham Hip Resurfacing (BHR) system provides good functional outcomes and durability in young, active men. We reviewed the survivorship and clinical outcomes of patients who underwent BHR with a minimum follow-up of 10 years. Methods: We analyzed survivorship using the Kaplan-Meier method. Functional scoring was performed using the Harris Hip Score (HHS), the University of California, Los Angeles (UCLA) Activity Score, and a visual analogue scale (VAS). Results: In total, 211 patients (243 hips) were included in the study. Of these, 107 patients (127 hips) were available for long-term clinical follow-up, with a mean duration of 12.4 +/- 1.4 years. The proportion of male participants with BHRs surviving past 13 years was 93.8% (95% confidence interval [CI] 87.9%-100%) compared with 87% (95% CI 77.8%-97.3%) of female patients. Eleven patients (11 hips) underwent BHR revision. Upon final follow-up, the median HHS was 93.9 in males and 93.6 in females (p = 0.27); median UCLA Activity Score was 8.2 in males and 7.2 in females (p < 0.001), and the median VAS score was 81.9 in males and 81.3 in females (p = 0.35). The median acetabular component inclination was 45.5 degrees +/- 6.0 degrees (range 34.6 degrees 57.2 degrees) in males and 44.6 degrees +/- 5.9 degrees (range 29 degrees-58.9 degrees) in females. The most common femoral head size was 50 mm with a 56 mm or 58 mm cup (36.3%). Conclusion: This study confirms that BHR provides good to excellent functional outcomes, lasting functional improvements, and acceptable durability beyond 10 years in men. Survivorship following BHR is inferior in women; however, HHS and VAS scores were similar in women and men.