Could larger diameter of 4th generation ceramic bearing increase the rate of squeaking after THA?: A retrospective study

The present study aimed to evaluate the clinical outcomes and bearing-specific complications in a single center of 135 delta ceramic-on-ceramic (COC) total hip arthroplasties (THAs) and explore the occurrence rate of squeaking in 4th generation COC THAs and collate the risk factors for squeaking. We retrospectively analyzed consecutive cohorts of 127 patients (135 hips) who had primary THA with delta COC bearings in our hospital between April 2010 and April 2012. Preoperative Harris hip score (HHS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, and University of California Los Angeles (UCLA) activity score were evaluated preoperatively and postoperatively. We also evaluated ceramic fracture, squeak, mid-term results, and survival. In our study, the final patient final follow-up date was July 31, 2016. The mean preoperative HHS improved from 39.5 to 93.1 points. Mean preoperative UCLA score was 3.2 points, improving to 8.2 points. The mean preoperative total WOMAC score was 55.5 points and the mean total WOMAC score was 13.3 points at the final follow-up. The Kaplan–Meier survival plot of revision for any reason as the end point was 98.5% and survival with ceramic fracture as the end point was 99.2% at a mean of 70 months’ follow-up. One post-operative ceramic liner rim fracture occurred at 50 months after surgery. Thirteen of the 135 hips produced a squeaking sound. There were no significant differences in gender (P = .56), age (P = .20), body mass index (BMI) (P = .11), diagnosis (P = .46), cup inclination (P = .36), or cup anteversion (P = 1.0) between the squeaking and non-squeaking groups. However, the incidence of squeaking in the 36 mm COC femoral head bearings was higher than in the 28 mm size (13.6% vs 2.1%, P = .033). The 4th generation COC bearing performed well and provides an encouraging rate of survival with no osteolysis or loosening. However, we found that a squeaking sound associated with use of the delta ceramic occurred at a rate of 9.6%, with the larger-diameter heads having significantly higher incidence.