title: A new software tool (VA-BATTS) to calculate bending, axial, torsional and transverse shear stresses within bone cross sections having inhomogeneous material properties.
abstract: BACKGROUND
  This study introduces, validates and demonstrates a new automated software tool (VA-BATTS) to calculate bone stresses within a bone cross section subjected to bending, axial, torsional and transverse shear far-field loading conditions, using quantitative computed tomography (QCT) data.
  
  
  METHODS
  A QCT image is imported and processed to generate a 2D finite element (FE) mesh of the bone with inhomogeneous (CT-based) transversely isotropic material properties. Bending and axial stresses are determined using inhomogeneous beam theory; torsional and transverse shear stresses are calculated using a new 2D FE formulation.
  
  
  RESULTS
  Validation studies show excellent agreement between results obtained using VA-BATTS and results obtained using analytical 2D models and inhomogeneous 3D FE models.
  
  
  CONCLUSIONS
  Out-of-plane bone stresses can be accurately calculated using a 2D analysis. Material inhomogeneity can have a marked effect on predicted stresses. In three-point bending experiments, transverse shear may present important contributions to the failure potential. The software is available at https://simtk.org/home/va-batts.
authors.affiliation: Bone and Joint Center of Excellence, VA Palo Alto Health Care System, Palo Alto, CA 94304, USA. kourtis@stanford.edu
authors.forename: Lampros C
authors.initials: LC
authors.lastname: Kourtis
authors.forename: Dennis R
authors.initials: DR
authors.lastname: Carter
authors.forename: Haneesh
authors.initials: H
authors.lastname: Kesari
authors.forename: Gary S
authors.initials: GS
authors.lastname: Beaupre
mesh_terms: D016880:Anisotropy; D001696:Biomechanical Phenomena; D001842:Bone and Bones / Q000502:physiology*; D019245:Compressive Strength / Q000502:physiology*; D003198:Computer Simulation; D004548:Elasticity; D020342:Finite Element Analysis; D033081:Shear Strength / Q000502:physiology*; D012984:Software; D013314:Stress, Mechanical; D013718:Tensile Strength / Q000502:physiology*