The press-fit acetabular component: Fixation and bearing surfaces

In press-fit total hip arthroplasty (THA) the stability of the implant and wear are the main important factors for survival, in which the bearing is assumed to play an important role. The objectives of this thesis are: 1) to gain insight in the use of measurement tools to ease the estimate of the obtained press-fit by the definitive cup during implantation, and their influence on primary stability; 2) to determine if ceramic-on-polyethylene (CoPE), ceramic-on highly cross-linked polyethylene (CoHXLPE) or ceramic-on-ceramic (CoC) shows better outcomes, and 3) to investigate the influence of these bearings on short-term revision, specifically focusing on primary cup stability. In this thesis we found that dynamic trial fitting can help to achieve sufficient press-fit for the definitive implant by more precise assessment of the reamed acetabulum, without affecting the primary stability, holding the potential to prevent early and long-term revision. Focused on bearing choice, CoC outstands CoHXLPE, and CoHXLPE outstands CoPE on wear rates, conventional PE should therefore be avoided whenever possible. Finally, CoC is thought to be a potential key factor for the multifactorial problem of early migration and potential resulting aseptic loosening. CoC should be restricted to cases in which no impaired bone quality is expected and gaining primary stability intraoperatively is not troublesome. For younger patients, CoC and CoHXLPE are both a feasible option in press-fit THA, but CoC could considered more often due to the wear advantages, without the fear for ceramic fractures. For older patients HXLPE is considered the option of choice.