Validation of composite finite elements efficiently simulating elasticity of trabecular bone

Lars Ole Schwen, Uwe Wolfram

Research output: Contribution to journalArticle

Abstract

Patient-specific analyses of the mechanical properties of bones become increasingly important for the management of patients with osteoporosis. The potential of composite finite elements (CFEs), a novel FE technique, to assess the apparent stiffness of vertebral trabecular bone is investigated in this study. Segmented volumes of cylindrical specimens of trabecular bone are compared to measured volumes. Elasticity under uniaxial loading conditions is simulated; apparent stiffnesses are compared to experimentally determined values. Computational efficiency is assessed and recommendations for simulation parameters are given. Validating apparent uniaxial stiffnesses results in concordance correlation coefficients 0.69r(?)0.92 for resolutions finer than 168m, and an average error of 5.8% between experimental and numerical results at 24m resolution. As an application, the code was used to compute local, macroscopic stiffness tensors for the trabecular structure of a lumbar vertebra. The presented technique allows for computing stiffness using smooth FE meshes at resolutions that are well achievable in peripheral high resolution quantitative CT. Therefore, CFEs could be a valuable tool for the patient-specific assessment of bone stiffness.

Original languageEnglish
Pages (from-to)652-660
Number of pages9
JournalComputer Methods in Biomechanics and Biomedical Engineering
Volume17
Issue number6
Early online date1 Oct 2012
DOIs
Publication statusPublished - 2014

Keywords

  • apparent stiffness
  • composite finite elements
  • linearised elasticity
  • nanoindentation
  • trabecular bone
  • validation
  • IMAGE SEGMENTATION
  • MESH GENERATION
  • MODULUS
  • ALGORITHMS
  • MODEL
  • NANOINDENTATION
  • RESOLUTION
  • STRENGTH
  • FAILURE
  • LOAD

Cite this

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abstract = "Patient-specific analyses of the mechanical properties of bones become increasingly important for the management of patients with osteoporosis. The potential of composite finite elements (CFEs), a novel FE technique, to assess the apparent stiffness of vertebral trabecular bone is investigated in this study. Segmented volumes of cylindrical specimens of trabecular bone are compared to measured volumes. Elasticity under uniaxial loading conditions is simulated; apparent stiffnesses are compared to experimentally determined values. Computational efficiency is assessed and recommendations for simulation parameters are given. Validating apparent uniaxial stiffnesses results in concordance correlation coefficients 0.69r(?)0.92 for resolutions finer than 168m, and an average error of 5.8{\%} between experimental and numerical results at 24m resolution. As an application, the code was used to compute local, macroscopic stiffness tensors for the trabecular structure of a lumbar vertebra. The presented technique allows for computing stiffness using smooth FE meshes at resolutions that are well achievable in peripheral high resolution quantitative CT. Therefore, CFEs could be a valuable tool for the patient-specific assessment of bone stiffness.",
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Validation of composite finite elements efficiently simulating elasticity of trabecular bone. / Schwen, Lars Ole; Wolfram, Uwe.

In: Computer Methods in Biomechanics and Biomedical Engineering, Vol. 17, No. 6, 2014, p. 652-660.

Research output: Contribution to journalArticle

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