gms | German Medical Science

Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2018)

23.10. - 26.10.2018, Berlin

Young’s modulus and Poisson’s ratio of equine cancellous bone of the proximal humerus for numerical evaluation of biomechanical testing setups

Meeting Abstract

  • presenting/speaker Jan J. Lang - Technische Universität München, Klinikum rechts der Isar, Klinik für Unfallchirurgie, Klinik für Orthopädie und Sportorthopädie, München, Germany
  • Peter Föhr - Technische Universität München, Klinikum rechts der Isar, Klinik für Orthopädie und Sportorthopädie, München, Germany
  • Constantin von Deimling - Technische Universität München, Klinikum rechts der Isar, Klinik für Orthopädie und Sportorthopädie, München, Germany
  • Steven Deile - Königsee Implantate GmbH, Allendorf, Germany
  • Rüdiger von Eisenhart-Rothe - Technische Universität München, Klinikum rechts der Isar, Klinik für Orthopädie und Sportorthopädie, München, Germany
  • Martijn van Griensven - Technische Universität München, Klinikum rechts der Isar, Experimentelle Unfallchirurgie, München, Germany
  • Dirk Barnewitz - Tierärztliche Klinik der fzmb GmbH, Forschungszentrum für Medizintechnik und Biotechnologie, Bad Langensalza, Germany
  • Rainer Burgkart - Technische Universität München, Klinikum rechts der Isar, Klinik für Orthopädie und Sportorthopädie, München, Germany

Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2018). Berlin, 23.-26.10.2018. Düsseldorf: German Medical Science GMS Publishing House; 2018. DocPT16-363

doi: 10.3205/18dkou656, urn:nbn:de:0183-18dkou6568

Veröffentlicht: 6. November 2018

© 2018 Lang 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 http://creativecommons.org/licenses/by/4.0/.


Gliederung

Text

Objectives: Biomechanical investigations often need a suitable testing setup to create generic results. Generally, experimental setups are not only designed for human bone but also for a range of animal models that are used in preclinical biomechanical studies. Numerical methods can be used during the design phase to validate the applicability and functionality of the setups before final assembly. To assure that all kinds of long bone animal models can be tested, horse is used as a representative to test on the large and sturdy end. This study focuses on the determination of material parameters of equine cancellous bone, which are lacking in literature, in order to be able to numerically validate a torsional test device for different bone models.

Methods: 47 bone cubes (edge length: 12mm) were examined with a total number of 141 compression tests on a uniaxial loading device (Zwick/Roell, ZwickiLine Z2.5). The samples were obtained by embedding a proximal equine humerus in a polyurethane (PU) block and then cutting a transversal grit into the block with a bandsaw. After that, all samples were marked to preserve the original orientation. A disk (thickness: 12 mm) was axially cut from the bone to obtain the single cubes. All cubes were optically examined and only the ones with full cancellous bone material were tested. The compression tests were performed non-destructively for all orientations to determine anisotropic features.

129 compression tests were used to determine the Young's modulus and 12 tests in combination with an optical observation setup were used for the determination of the Poisson's ratio (Figure 1 [Fig. 1]).

Results and conclusion: All three orientations of the bone cubes were successfully evaluated. For the Young's modulus a one-way ANOVA followed by Tukey's post hoc test showed that the results for the anterior-posterior direction (121±49 MPa) were significantly higher (p=0.032) than for the proximal-distal orientation (96±42 MPa). For the medial-lateral direction (102±45 MPa) no significant difference to the other orientations was found. The Poisson's ratio was determined to 0.15±0.08. No significant dependency of orientation was observed. We conclude that the orientation dependence of the Young's modulus points out the anisotropic structure of equine cancellous bone. It also confirms the applicability of the method for the determination of orientation dependent material parameters. This method can also be transferred to investigate the anisotropy of human bone. To obtain the best possible outcome for the finite element analysis of the torsional test device an anisotropic material model is strongly recommended.