How screw connections influence the primary stability of acetabular cups under consideration of different bone models.

Abstract Introduction Good osteointegration of implants requires sufficient primary stability. Aim of this study was to examine the influence of screw fixation on the primary stability of press-fit cups. Methods Two press-fit acetabular cups were tested with regard to the influence and number of screws and their primary stability. Results For the relatively thin-walled Allofit®-S cup, an influence of the number of screws on the different forms of movement could be demonstrated. Conclusions We see a clear influence of the cup wall thickness on the elastic deformability and accordingly on the primary stability of the examined cups.