<div class="csl-bib-body">
<div class="csl-entry">Stefanek, P., Silva Henao, J. D., Reisinger, A., Pahr, D., & Synek, A. (2024, July 1). <i>Screw pull-out force prediction in porcine radII using computationally efficient nonlinear µFE models</i> [Conference Presentation]. 29th Congress of the European Society of Biomechanics, Edinburgh, United Kingdom of Great Britain and Northern Ireland (the). http://hdl.handle.net/20.500.12708/205278</div>
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dc.identifier.uri
http://hdl.handle.net/20.500.12708/205278
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dc.description.abstract
SCREW PULL-OUT FORCE PREDICTION IN PORCINE RADII USING
COMPUTATIONALLY EFFICIENT NONLINEAR µFE MODELS
Pia Stefanek (1), Juan Diego Silva-Henao (2), Andreas Reisinger (2), Dieter H. Pahr (1,2), Alexander
Synek (1)
1.Institute of Lightweight Design and Structural Biomechanics, TU Wien, Austria;
2.Division Biomechanics, Karl Landsteiner University of Health Sciences, Austria
Introduction
In mechanical simulations of bone-implant systems,
modelling the screw-bone contact interface and the pre-
damage due to screw-insertion are major challenges. To
maintain computational efficiency, the contact interface
can be simplified using a fully-bonded interface or by
applying a method developed by Steiner et al. [1], which
is based on the deletion of interface elements under
tension. Pre-damage is either not considered [2] or
included in a simplified way by reducing the elastic
modulus in proximity to the screw [1]. In this study, we
test if a highly efficient materially nonlinear µFE solver
(ParOSol-NL [3]) can predict the maximum screw pull-
out force in porcine radii. Four different µFE simulation
types were performed to test if accurate predictions were
required including the simplified screw-bone contact
interface and/or the pre-damage.
Methods
Ten cylindrical specimens (diameter and height
~20mm), were derived from porcine distal radii. A
central pilot hole was drilled, and a 2.5mm locking
screw was implanted. Using a custom-designed testing
apparatus, cyclic tensile loading with increasing
amplitude was applied until failure. Segmented µCT
images were acquired from the unloaded, pre-drilled
specimens. Images were cut in cuboids and resampled
to a resolution of 36µm. Virtual screw insertion was
done to obtain voxel-based µFE models (Fig. 1a).
Linear-elastic material properties were assigned to the
screw and a nonlinear damaged-based material model
was used for the bone [3]. Material parameters were
adapted for porcine bone according to [4]. Different
simulations were performed using ParOSol-NL and
compared (Fig. 1b): A fully-bonded bone-screw
interface (FB), interfacial tensionally-strained element
deletion (TED, see Steiner et al. [1]), TED with
inclusion of a pre-damaged region around the screw
(TED-P) and FB using adapted material parameters
(FB-A). For TED-P a small cylindrical region around
the screw was selected where the pre-damage was
initialized with 0.9. The material parameters for FB-A
were found by calculating the mean scaling factor for
the FB results to match the experiments. Experimental
and simulated maximum pull-out forces were compared.
Results
Simulations and experiments showed high correlations
(R2 ≥0.84, Fig. 2). The root mean squared error was
highest for FB (239N), lower with TED (143N), and
lowest for TED-P (43N) and TED-A (44N). 1:1
agreements was reached for TED-P and FB-A models.
Conclusion
Experimental pull-out forces could be predicted with
high correlations using ParOSol-NL. The FB model led
to an overestimation of the maximum forces. Using a
simplified contact model alone (TED) slightly improved
the predictions, whereas adding pre-damage finally led
to a good 1:1 agreement. FB-A revealed that a similar
“tuned” prediction of maximum force could also be
attained through the adaptation of the elastic modulus
alone. However, this study is based on only one loading
scenario and a rather small sample size. Further research
is needed to fully determine the relevance of contact and
pre-damage implementations for accurate pull-out force
predictions in bone-screw simulations.
References
1. Steiner et al, J Orthop Res 35:2415-2424, 2017.
2. Ovesy et al, J Mech Behav Biomed Mater 126: 105002,
2022.
3. Stipsitz et al, Biomech Model Mechano 19:861-874, 2019.
4. Chen et al, J Mech Behav Biomed Mater 65:644-651, 2017.
en
dc.language.iso
en
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dc.subject
orthopaedic implant
en
dc.subject
bone
en
dc.subject
finite element
en
dc.title
Screw pull-out force prediction in porcine radII using computationally efficient nonlinear µFE models
en
dc.type
Presentation
en
dc.type
Vortrag
de
dc.contributor.affiliation
Karl Landsteiner University of Health Sciences, Austria
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dc.contributor.affiliation
Karl Landsteiner University of Health Sciences, Austria
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dc.type.category
Conference Presentation
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tuw.researchTopic.id
M6
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tuw.researchTopic.id
C6
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tuw.researchTopic.name
Biological and Bioactive Materials
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tuw.researchTopic.name
Modeling and Simulation
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tuw.researchTopic.value
30
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tuw.researchTopic.value
70
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tuw.publication.orgunit
E317 - Institut für Leichtbau und Struktur-Biomechanik
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tuw.author.orcid
0000-0002-9679-8226
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tuw.author.orcid
0000-0002-6160-0259
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tuw.author.orcid
0000-0002-5822-2082
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tuw.author.orcid
0000-0002-5253-7403
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tuw.event.name
29th Congress of the European Society of Biomechanics
