gms | German Medical Science

Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2019)

22. - 25.10.2019, Berlin

Establishing a 3D printed artificial human bone sample for biomechanical testing

Meeting Abstract

  • presenting/speaker Felix Wunderlich - Universitätsmedizin Mainz, Zentrum für Orthopädie und Unfallchirurgie, Mainz, Germany
  • Dorothea Mehler - Universitätsmedizin Mainz, Zentrum für Orthopädie und Unfallchirurgie, Mainz, Germany
  • Katharina Degner - Hochschule Rhein Main, Wiesbaden, Germany
  • Christian Glockner - Hochschule Rhein Main, Wiesbaden, Germany
  • Pol Maria Rommens - Universitätsmedizin Mainz, Zentrum für Orthopädie und Unfallchirurgie, Mainz, Germany
  • Dominik Gruszka - Universitätsmedizin Mainz, Zentrum für Orthopädie und Unfallchirurgie, Mainz, Germany

Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2019). Berlin, 22.-25.10.2019. Düsseldorf: German Medical Science GMS Publishing House; 2019. DocAB35-1422

doi: 10.3205/19dkou242, urn:nbn:de:0183-19dkou2424

Veröffentlicht: 22. Oktober 2019

© 2019 Wunderlich 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: Currently used composite bone models (e.g. Sawbones) for biomechanical testing are expensive, do not represent the interindividual anatomical differences and their mechanical characteristics are barely comparable to human bone. We therefore aimed for creating a new 3D printed artificial bone sample (ABS) produced on the basis of clinical CT scans with biomechanical attributes closer to human bone and eligible for biomechanical testing.

Methods: Based on CT-Scan data of a fresh-frozen macroscopically intact cadaveric ulna we created a digital template via 3-layer Standard Tesselation Language (STL) Net using computer software, matching the 3D printing requirements. The cortical and cancellous bone areas were developed in different techniques. Several samples were printed to find the appropriate material thickness, porosity and trabecular grid structure. Grid structure was set to 0.8mm and 1.2mm in different samples. We used Polyamid 12 (PA12) as raw material, which is a thermoplastic linear built plastic material. The bone templates were augmented with mounting brackets located on both ends for following biomechanical testing. The sawbone and cadaveric ulna were embedded in Polymethylmetacrylat (PMMA) for mounting purposes. Thereafter biomechanical testing via tension and bending force was conducted in a universal testing machine. We tested two 3D printed ABS with different porosity of the cancellous bone versus fresh-frozen cadaveric ulna and a sawbone ulna. Tension and bending force were applied over 5mm/min. All samples were loaded to failure in both tension and bending.

We hypothesized that both 3D printed ABS matched human bone characteristics better than sawbone.

Results: In total four different samples (ABS PA12-0.8; ABS PA12-1.2; sawbone ulna; cadaveric ulna) were biomechanically tested for both tension and bending force. All samples were similar in material thickness (diameters 11mm for PA12-0.8, PA12-1.2 and cadaveric ulna, 12mm for sawbone) as well as in length and anatomical shape (i.e. Ulna bone). Testing for tension force showed a maximum load of 3361,3 Newton (N) for the sawbone sample. The cadaveric ulna did withstand 825N of tensional strength whereas the PA12-1.2 sample withstand 856,3N and the PA12-0.8 sample 1026,3N. For bending force testing a strength of 1670,5N could be applied to the sawbone sample. Maximum load for cadaveric ulna bone was 532,9N, 490,3N for PA12-0.8 and 385,8N for PA 12-1.2, respectively.

Conclusion: Our testing of a pair of 3D printed ABS versus a composite bone model and a cadaveric bone showed better similarity to human bone mechanical characteristics in tension and bending load for 3D printed ABS. Especially the ABS PA 12 1.2 showed very close results to those reached by the cadaveric specimen. Further research covering shearing and rotational forces and further 3D printed ABS with different porosity or materials is needed.