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

Ahmed GA 1, 2 , Auge L 1 , Loke J 1 , Fonseca Ulloa CA 1 , Fölsch C 1 ,2 , Rickert M 1, 2 , Ishaque BA 1 ,2 , Jahnke A 1

J Orthop. 2020 Jun 6:21:302-308. doi: 10.1016/j.jor.2020.05.020 . eCollection 2020 Sep-Oct.

  1. Laboratory of Biomechanics, Justus-Liebig-University Giessen, Klinikstrasse 29, 35392, Giessen, Germany.
  2. Department of Orthopaedics and Orthopaedic Surgery, University Hospital Giessen and Marburg (UKGM), Klinikstraße 33, 35392, Giessen, Germany.


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.

Keywords: Cementless; Cup component; Hip endoprosthetics; Primary stability; Screw connection.