gms | German Medical Science

Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2016)

25.10. - 28.10.2016, Berlin

Comparison of the tear-out behavior in acetabular components of human coxal bones

Meeting Abstract

  • presenting/speaker Robert Möbius - Institut für Anatomie, Universität Leipzig, Leipzig, Germany
  • Stefan Schleifenbaum - KOUP, Universitätsklinikum Leipzig, Leipzig, Germany
  • Ronny Grunert - Fraunhofer-Institut IWU, Dresden, Germany
  • Sabine Löffler - Institut für Anatomie, Universität Leipzig, Leipzig, Germany
  • Michael Werner - Fraunhofer-Institut IWU, Dresden, Germany
  • Torsten Prietzel - HELIOS Klinik Blankenhain, KOUP, Universitätsklinikum Leipzig, Blankenhain, Germany
  • Niels Hammer - Department of Anatomy, University of Otago, Dunedin, New Zealand

Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2016). Berlin, 25.-28.10.2016. Düsseldorf: German Medical Science GMS Publishing House; 2016. DocPO15-1051

doi: 10.3205/16dkou578, urn:nbn:de:0183-16dkou5784

Veröffentlicht: 10. Oktober 2016

© 2016 Möbius et al.
Dieser Artikel ist ein Open-Access-Artikel und steht unter den Lizenzbedingungen der Creative Commons Attribution 4.0 License (Namensnennung). Lizenz-Angaben siehe



Objectives: The removal of well-fixed acetabular components following THA (total hip arthroplasty) is a difficult operation and often accompanied by the loss of acetabular bone stock. The optimal method for fixation is still under discussion. The aim of this study was to compare the mechanical properties and failure characteristics in the bone-implant-interface between osseo-integrated and non-integrated sockets and various types of THA acetabular components.

Methods: Eleven human coxal bones from seven body donors (Institute of Anatomy, University Leipzig) with lifetime implanted acetabular components were used for a mechanical tear-out testing setup. The body donors had the following types of implants: screw sockets (n=4), cemented polyethylene cups (n=3) and press-fit system (n=1). Additionally, three native coxal bones were used for post-mortem implantion of three size matched screw sockets. The coxal bones containing the different types of sockets were mounted to the mechanical testing machine and a uniaxial tensile test until failure was performed for each socket. The (parameters) axial failure load and mechanical work for tear-out were introduced as measures to determine the stability of acetabular components following THA.

Results and Conclusion: The mean axial failure load was 1.61 ± 0.26 kN for the osseo-integrated screw sockets and 1.18 ± 0.24 kN for the cemented polyethylene cups. The axial failure load for the osseo-integrated press-fit system was 2.06 kN. There were no significant differences (p=0.874). In the non-integrated screw sockets the mean failure load was 1.23 ± 0.39 kN. Comparison of the mean axial failure load between the osseo-integrated and the post-mortem implanted screw sockets yielded no significant differences (p=0.253). Osseous failure patterns differed especially for the screw sockets compared to the cemented polyethylene cups.

The different implant types yielded similar tear-out resistance and related mechanical work with the only exception of a press-fit implant. Osseo-integrated and non-integrated screw sockets also yielded quite similar tear-out resistance and related mechanical work. Therefore, osseo-integration did not greatly influence the strength of the bone-implant-interface in cementless screw sockets. However, given the high failure load, the mechanical load as well as the related bone failure patterns, removal should not be performed by means of tear out in favor of osteotomes or other cutting devices to preserve the acetabular bone stock.