Third- and fourth- generation ceramic-on-ceramic total hip arthroplasty: a ten- to sixteen year follow-up study

Third-generation alumina is being replaced with fourth-generation alumina matrix composite (AMC) in ceramic-on-ceramic total hip arthroplasty (THA), however, comparative clinical studies at a long-term are lacking. We aimed to compare third- and fourth-generation ceramic-on-ceramic THA at a minimum follow-up of ten years.

A total of 332 third-generation ceramic-on-ceramic THAs (302 patients) performed between 2010 and 2015 were compared with 185 fourth-generation (165 patients) during the same time period. Changes in the Harris Hip Score (HHS), Euro Qol-5D (EQ-5D), Visual Analogue Scale (VAS) satisfaction instruments, complications, survival rates for reoperation and the radiographic results were compared.

At the latest follow-up, the mean HHS, EQ-5D and VAS scores were similar between the groups. There were four dislocations (1.2%) in the alumina group (one with a 28-mm and three with a 32-mm femoral head), and two (1.1%) in the AMC group (all with a 36-mm). Four (1.2%) patients in the alumina group and eight (2.1%) in the AMC group reported occasional noises but no squeaking. One 28-mm femoral head fractured in the alumina group. The 15-year survival rate for any reoperation was 95.8% (95% confidence interval [CI]: 93.6% to 97.9%) for alumina-on-alumina THAs, and 96.3% (95% CI: 93.5-99.0) for the AMC group (p = 0.8).

Both third- and fourth-generation ceramic-on-ceramic THA can provide excellent results in most patients. Although no ceramic-related complications occurred in the AMC group, fourth-generation bearings were not found to be superior to third-generation alumina bearings overall. A thorough understanding of implant characteristics and surgical technique is essential for an accurate clinical interpretation when assessing different brands in THA.