A nonlinear finite element model validation study based on a novel experimental technique for inducing anterior wedge-shape fractures in human vertebral bodies in vitro

E. Dall'Ara*, R. Schmidt, D. Pahr, P. Varga, Y. Chevalier, J. Patsch, F. Kainberger, P. Zysset

*Corresponding author for this work

Research output: Journal article (peer-reviewed)Journal article

94 Citations (Scopus)

Abstract

Vertebral compression fracture is a common medical problem in osteoporotic individuals. The quantitative computed tomography (QCT)-based finite element (FE) method may be used to predict vertebral strength in vivo, but needs to be validated with experimental tests. The aim of this study was to validate a nonlinear anatomy specific QCT-based FE model by using a novel testing setup. Thirty-seven human thoracolumbar vertebral bone slices were prepared by removing cortical endplates and posterior elements. The slices were scanned with QCT and the volumetric bone mineral density (vBMD) was computed with the standard clinical approach. A novel experimental setup was designed to induce a realistic failure in the vertebral slices in vitro. Rotation of the loading plate was allowed by means of a ball joint. To minimize device compliance, the specimen deformation was measured directly on the loading plate with three sensors. A nonlinear FE model was generated from the calibrated QCT images and computed vertebral stiffness and strength were compared to those measured during the experiments. In agreement with clinical observations, most of the vertebrae underwent an anterior wedge-shape fracture. As expected, the FE method predicted both stiffness and strength better than vBMD (R2 improved from 0.27 to 0.49 and from 0.34 to 0.79, respectively). Despite the lack of fitting parameters, the linear regression of the FE prediction for strength was close to the 1:1 relation (slope and intercept close to one (0.86kN) and to zero (0.72kN), respectively). In conclusion, a nonlinear FE model was successfully validated through a novel experimental technique for generating wedge-shape fractures in human thoracolumbar vertebrae.

Original languageEnglish
Pages (from-to)2374-2380
Number of pages7
JournalJournal of Biomechanics
Volume43
Issue number12
DOIs
Publication statusPublished - 26 Aug 2010
Externally publishedYes

Keywords

  • Bone mineral density
  • Bone strength
  • Finite element modeling
  • Mechanical testing
  • Osteoporosis
  • Humans
  • Middle Aged
  • Male
  • Tomography, X-Ray Computed
  • Osteoporosis/complications
  • Spinal Fractures/diagnostic imaging
  • Aged, 80 and over
  • Adult
  • Female
  • Finite Element Analysis
  • Thoracic Vertebrae/diagnostic imaging
  • Bone Density
  • Lumbar Vertebrae/diagnostic imaging
  • Risk Factors
  • Biomechanical Phenomena
  • Models, Biological
  • Fractures, Compression/etiology
  • Aged
  • In Vitro Techniques
  • Nonlinear Dynamics

ASJC Scopus subject areas

  • Biophysics
  • Orthopedics and Sports Medicine
  • Biomedical Engineering
  • Rehabilitation

Fingerprint

Dive into the research topics of 'A nonlinear finite element model validation study based on a novel experimental technique for inducing anterior wedge-shape fractures in human vertebral bodies in vitro'. Together they form a unique fingerprint.

Cite this