Ceramic-on-ceramic bearings: can we avoid the complications? Long-term outcomes of big head CoC bearings in primary total hip arthroplasty.

Background: Ceramic-on-ceramic (CoC) bearings offer superior wear characteristics and a low coefficient of friction, yet their use is limited due to reported risks of ceramic fractures in the literature. We assessed our series of patients undergoing total hip arthroplasty (THA) with 36 mm CoC bearings.

Methods: A Retrospective cohort study of 385 patients (442 hips) who underwent primary THA between 2008 and 2018 was conducted. Twenty-three patients died and 36 patients (38 hips) were lost to follow-up. Data were prospectively collected for 326 patients (381 hips) who had uncemented THA with 36 mm-CoC bearings. Kaplan-Meier analysis was used to assess survival with ceramic fracture or revision due to squeaking as endpoints. Clinical evaluation was done using EQ-5D and Oxford Hip Score (OHS). Incidence of squeaking and ceramic-related complications, dislocation, and infection were recorded.

Results: Survival of CoC bearings was 100% (95% CI 96.7-100%) at 14 years with ceramic fracture, failure, or revision due to squeaking as the endpoint. Mean OHS was 44.5 (30-48). Occasional squeaking was reported by 28 patients (7.3%), without pain or revision surgery due to squeaking. Squeaking correlated significantly with younger age (< 60 years; P = 0.002). Dislocations occurred in 2 cases (0.5%) and prosthetic joint infection in 1 (0.3%).

Conclusions: THA with CoC bearings using 4th generation BIOLOX delta ceramic heads yielded excellent results at 14 years with a mean follow-up duration of 9.39 years, with no ceramic fractures or squeaking-related revisions. The optimal position of the bearing surface is crucial to mitigate fracture risk, while larger heads reduce dislocation risk. The observed low infection rate may be attributed to reduced biofilm formation on ceramic surfaces.