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How accurately can subject-specific finite element models predict strains and strength of human femora? Investigation using full-field measurements

Grassi, Lorenzo LU ; Väänänen, Sami P.; Ristinmaa, Matti LU ; Jurvelin, Jukka S. and Isaksson, Hanna LU (2016) In Journal of Biomechanics 49(5). p.802-806
Abstract
Subject-specific finite element models have been proposed as a tool to improve fracture risk assessment in individuals. A thorough laboratory validation against experimental data is required before introducing such models in clinical practice. Results from digital image correlation can provide full-field strain distribution over the specimen surface during in vitro test, instead of at a few pre-defined locations as with strain gauges. The aim of this study was to validate finite element models of human femora against experimental data from three cadaver femora, both in terms of femoral strength and of the full-field strain distribution collected with digital image correlation. The results showed a high accuracy between predicted and... (More)
Subject-specific finite element models have been proposed as a tool to improve fracture risk assessment in individuals. A thorough laboratory validation against experimental data is required before introducing such models in clinical practice. Results from digital image correlation can provide full-field strain distribution over the specimen surface during in vitro test, instead of at a few pre-defined locations as with strain gauges. The aim of this study was to validate finite element models of human femora against experimental data from three cadaver femora, both in terms of femoral strength and of the full-field strain distribution collected with digital image correlation. The results showed a high accuracy between predicted and measured principal strains (R2=0.93, RMSE=10%, 1600 validated data points per specimen). Femoral strength was predicted using a rate dependent material model with specific strain limit values for yield and failure. This provided an accurate prediction (<2% error) for two out of three specimens. In the third specimen, an accidental change in the boundary conditions occurred during the experiment, which compromised the femoral strength validation. The achieved strain accuracy was comparable to that obtained in state-of-the-art studies which validated their prediction accuracy against 10–16 strain gauge measurements. Fracture force was accurately predicted, with the predicted failure location being very close to the experimental fracture rim. Despite the low sample size and the single loading condition tested, the present combined numerical-experimental method showed that finite element models can predict femoral strength by providing a thorough description of the local bone mechanical response. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Finite element, Human femur, Experimental validation, Bone strength
in
Journal of Biomechanics
volume
49
issue
5
pages
802 - 806
publisher
Elsevier
external identifiers
  • pmid:26944687
  • scopus:84960489840
  • wos:000374071100025
ISSN
1873-2380
DOI
10.1016/j.jbiomech.2016.02.032
language
English
LU publication?
yes
id
aabdb086-4a83-40d2-97ce-4117ead4bc76 (old id 8726552)
date added to LUP
2016-02-19 11:10:57
date last changed
2017-10-22 03:10:08
@article{aabdb086-4a83-40d2-97ce-4117ead4bc76,
  abstract     = {Subject-specific finite element models have been proposed as a tool to improve fracture risk assessment in individuals. A thorough laboratory validation against experimental data is required before introducing such models in clinical practice. Results from digital image correlation can provide full-field strain distribution over the specimen surface during in vitro test, instead of at a few pre-defined locations as with strain gauges. The aim of this study was to validate finite element models of human femora against experimental data from three cadaver femora, both in terms of femoral strength and of the full-field strain distribution collected with digital image correlation. The results showed a high accuracy between predicted and measured principal strains (R2=0.93, RMSE=10%, 1600 validated data points per specimen). Femoral strength was predicted using a rate dependent material model with specific strain limit values for yield and failure. This provided an accurate prediction (&lt;2% error) for two out of three specimens. In the third specimen, an accidental change in the boundary conditions occurred during the experiment, which compromised the femoral strength validation. The achieved strain accuracy was comparable to that obtained in state-of-the-art studies which validated their prediction accuracy against 10–16 strain gauge measurements. Fracture force was accurately predicted, with the predicted failure location being very close to the experimental fracture rim. Despite the low sample size and the single loading condition tested, the present combined numerical-experimental method showed that finite element models can predict femoral strength by providing a thorough description of the local bone mechanical response.},
  author       = {Grassi, Lorenzo and Väänänen, Sami P. and Ristinmaa, Matti and Jurvelin, Jukka S. and Isaksson, Hanna},
  issn         = {1873-2380},
  keyword      = {Finite element,Human femur,Experimental validation,Bone strength},
  language     = {eng},
  number       = {5},
  pages        = {802--806},
  publisher    = {Elsevier},
  series       = {Journal of Biomechanics},
  title        = {How accurately can subject-specific finite element models predict strains and strength of human femora? Investigation using full-field measurements},
  url          = {http://dx.doi.org/10.1016/j.jbiomech.2016.02.032},
  volume       = {49},
  year         = {2016},
}