Influence of head size and sex on the five- year survival of ceramic-on-ceramic hip resurfacing
Aims
Ceramic- on- ceramic hip resurfacing (CoCHR) has been introduced to mitigate the risk of adverse tissue reactions associated with metal-on-metal hip resurfacing (MoMHR), particularly in females and smaller component sizes. This study evaluated: the survival of the ReCerf hybrid CoCHR up to five years; the impact of sex and component size on revision; and improvement in functional outcomes as measured by the Oxford Hip Score (OHS) and the University of California, Los Angeles Activity Scale (UCLA).
Methods
An international retrospective study included 604 consecutive patients (336 males, 268 females; mean age 50.1 years (20 to 80)) who underwent CoCHR from September 2018 to January 2023. Kaplan-Meier analysis assessed up to five-year survival, with log-rank tests comparing outcomes by sex and femoral head size. Cox proportional hazards regression quantified revision risk.
Results
Mean follow-up was 4.04 years (1.44 to 6.35). Survival in 128 hips which had five-year follow-up was 98.0% (95% CI 96.3 to 99.0): 97.6% for males (95% CI 94.7 to 98.9), 98.5% for females (95% CI 96.0 to 99.4), 98.5% for femoral head sizes < 50 mm (95% CI 96.1 to 99.4), and 97.5% for head sizes ≥ 50 mm (95% CI 94.6 to 98.8). Females had a revision hazard ratio (HR) of 0.79 (95% CI 0.14 to 4.26; p = 0.780) and an increase in head diameter by 1 mm of 1.01 (95% CI 0.83 to 1.23; p = 0.890), demonstrating no significant impact of sex or head size on revision incidence. Significant improvements in OHS and UCLA scores were observed for all patients (preoperative OHS 22.3 (SD 8.4) and postoperative OHS 45.0 (SD 4.1); preoperative UCLA 4.96 (SD 2.2) and postoperative UCLA 7.97 (SD 1.7)).
Conclusion
CoCHR demonstrated excellent patient-reported outcome improvement and survival up to five years, irrespective of sex or implant size, comparing favourably to MoMHR. Longer- term follow-up is required to confirm these outcomes.