gms | German Medical Science

German Congress of Orthopaedics and Traumatology (DKOU 2023)

24. - 27.10.2023, Berlin

Load stable posterior column acetabulum fracture fixation: A biomechanical comparability study

Meeting Abstract

  • presenting/speaker Ivan Zderic - AO Research Institute Davos, Davos, Switzerland
  • Till Berk - AO Research Institute Davos, Davos, Switzerland; University Hospital Zurich, Zurich, Switzerland
  • Peter Schwarzenberg - AO Research Institute Davos, Davos, Switzerland
  • Torsten Pastor - AO Research Institute Davos, Davos, Switzerland; Cantonal Hospital Lucerne, Lucerne, Switzerland
  • Roman Pfeifer - Universitätsspital Zürich, Klinik für Traumatologie, Zürich, Switzerland
  • Sascha Halvachizadeh - University Hospital Zurich, University of Zurich, Zurich, Switzerland
  • R. Geoff Richards - AO Research Institute Davos, Davos, Switzerland
  • Boyko Gueorguiev - AO Research Institute Davos, Davos, Switzerland
  • Hans-Christoph Pape - Klinik für Traumatologie, Universitätsspital Zürich, Zurich, Switzerland

Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2023). Berlin, 24.-27.10.2023. Düsseldorf: German Medical Science GMS Publishing House; 2023. DocIN37-3428

doi: 10.3205/23dkou697, urn:nbn:de:0183-23dkou6971

Published: October 23, 2023

© 2023 Zderic et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License. See license information at



Objectives: The rate of acetabular fractures (AF) are increasing in all industrial nations with posterior column fractures (PCF) accounting for 18.5−22% of these fractures. Treating displaced AFs in elderly patients is a known challenge. The optimal surgical strategy using open reduction and internal fixation (ORIF) or total hip arthroplasty (THA), or both methods in combination, remains debated. Additionally, with either method, post-operative weight bearing protocols are also ambiguous. The aim of this study was to evaluate construct stiffness and load to failure following a PCF stabilization with standard plate osteosynthesis, screw fixation, and THA with a screwable cup under full weight being conditions.

Methods: Twelve anatomical composite osteoporotic pelvises were used in this study. A posterior column fracture according to the Letournel classification was created in 24 hemi-pelvises constructs that were stratified into three groups (N = 8) as follows:

  • Group PCPF: Posterior column fracture with plate fixation
  • Group PCSC: Posterior column fracture with screwable cup fixation
  • Group PCSF: Posterior column fracture with screw fixation

Figure 1 [Fig. 1]

Biomechanical testing was performed on a servohydraulic material testing system. The samples were loading cyclically at a rate of 2 Hz with a valley load of 20 N and a peak load starting at 200 N that was increased at a rate of 0.05 N/cycle until failure. Relative displacements of the bone fragments were measured using a stereographic camera system and outcome parameters were calculated.

Results and conclusion: Initial construct stiffness was 133.3 ± 27.5 N/mm, 154.8 ± 68.3 N/mm, and 107.3 ± 41.0 N/mm for the screw fixation, plate fixation, and cup fixation respectively, with no significant differences between the groups, p = 0.173. Furthermore, the number of cycles to 1 mm of total anterior displacement were 7,822 ± 2,281 cycles, 5,989 ± 3,440 cycles, and 3,662 ± 1,664 cycles, for the plate fixation, cup fixation, and screw fixation respectively, with a significant difference between the plate and screw fixation, p = 0.012.

Standard ORIF with plate osteosynthesis as well as primary THA with a screwable cup of PCF demonstrated encouraging results for a post-surgical-treatment concept with a full weight-bearing approach. Further biomechanical studies should be initiated using cadaver bones and larger sample sizes for a better understanding of AF treatment and full weight bearing and there potential as a treatment concept for PCF fixation.