CORR Insights®: Squeaking Is Common and Increases Over Time Among Patients With Long-term Follow-up After Ceramic-on-ceramic THA

Taniguchi et al. [⁷] retrospectively studied a small series of young patients who were treated with ceramic-on-ceramic (CoC) THA implants. The implanted ceramic was a third-generation material known as Biolox® Forte (CeramTec, Plochingen, Germany). and the follow-up period was long (11-16 years) compared with the follow-up of many other reported series. The authors’ primary purposes were to analyze the frequency of squeaking noises arising from the prosthetic hip bearing and to determine whether it becomes more common over time. About one-third of their patients reported that squeaking developed more than 5 years after implantation, suggesting that squeaking increases with the service life of the implant. The authors also found that the femoral component’s design may play an important role in squeaking. They noted that squeaking was more common with the Accolade titanium-molybdenum-zirconium-iron (TMZF) stem (Stryker, Mahwah NJ, USA) than with the SecurFit (Stryker, Mahwah, NJ, USA).

As pointed out by the authors [⁷], interest in CoC implants primarily arises from the low wear rate and low biologic reactivity associated with this bearing surface. In fact, most reported series highlighted the excellent long-term survivorship and low incidence of osteolysis of CoC implants in young, active patients [^1-3]. These studies also noted squeaking in 10% to 30% of patients and reported that squeaking is an important cause of revision. The source of squeaking of CoC THA implants is still being investigated, but it appears to be associated with issues unique to ceramic bearings, such as microseparation, edge loading, and stripe wear associated with the CoC bearing [^{4, 6}]. Simulator studies and retrievals of explanted components indicate the problem of micro-separation between the head and acetabulum during gait, causing edge loading that induces wear [^{4, 6}]. This is associated with stripe wear, but stripe wear is also associated with metal transfer to the femoral head [⁴]. Surface roughness is increased in places where there is stripe wear, and this increased roughness may result in vibrations that cause squeaking [⁶]. Much of our understanding of the CoC bearing comes from simulator studies, and long-term clinical follow-up is lacking to date.

Taniguchi et al.’s paper [⁷] is important because it provides long-term clinical data and highlights the possible influence of the femoral component in squeaking. In this series [⁷], the Accolade TMZF stem (Stryker) was associated with a higher incidence of squeaking than the SecurFit stem (Stryker) was. This titanium alloy is associated with substantial trunnion corrosion and has been recalled from clinical use, suggesting that corrosion plays a role in generating stripe wear and squeaking.