title: Trabecular plates and rods determine elastic modulus and yield strength of human trabecular bone.
abstract: The microstructure of trabecular bone is usually perceived as a collection of plate-like and rod-like trabeculae, which can be determined from the emerging high-resolution skeletal imaging modalities such as micro-computed tomography (μCT) or clinical high-resolution peripheral quantitative CT (HR-pQCT) using the individual trabecula segmentation (ITS) technique. It has been shown that the ITS-based plate and rod parameters are highly correlated with elastic modulus and yield strength of human trabecular bone. In the current study, plate-rod (PR) finite element (FE) models were constructed completely based on ITS-identified individual trabecular plates and rods. We hypothesized that PR FE can accurately and efficiently predict elastic modulus and yield strength of human trabecular bone. Human trabecular bone cores from proximal tibia (PT), femoral neck (FN) and greater trochanter (GT) were scanned by μCT. Specimen-specific ITS-based PR FE models were generated for each μCT image and corresponding voxel-based FE models were also generated in comparison. Both types of specimen-specific models were subjected to nonlinear FE analysis to predict the apparent elastic modulus and yield strength using the same trabecular bone tissue properties. Then, mechanical tests were performed to experimentally measure the apparent modulus and yield strength. Strong linear correlations for both elastic modulus (r(2) = 0.97) and yield strength (r(2) = 0.96) were found between the PR FE model predictions and experimental measures, suggesting that trabecular plate and rod morphology adequately captures three-dimensional (3D) microarchitecture of human trabecular bone. In addition, the PR FE model predictions in both elastic modulus and yield strength were highly correlated with the voxel-based FE models (r(2) = 0.99, r(2) = 0.98, respectively), resulted from the original 3D images without the PR segmentation. In conclusion, the ITS-based PR models predicted accurately both elastic modulus and yield strength determined experimentally across three distinct anatomic sites. Trabecular plates and rods accurately determine elastic modulus and yield strength of human trabecular bone.
authors.affiliation: Bone Bioengineering Laboratory, Department of Biomedical Engineering, Columbia University, New York, NY, USA. Electronic address: jw2857@columbia.edu.
authors.forename: Ji
authors.initials: J
authors.lastname: Wang
authors.affiliation: Bone Bioengineering Laboratory, Department of Biomedical Engineering, Columbia University, New York, NY, USA. Electronic address: bz2159@columbia.edu.
authors.forename: Bin
authors.initials: B
authors.lastname: Zhou
authors.affiliation: Bone Bioengineering Laboratory, Department of Biomedical Engineering, Columbia University, New York, NY, USA; McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA. Electronic address: xiaoweil@mail.med.upenn.edu.
authors.forename: X Sherry
authors.initials: XS
authors.lastname: Liu
authors.affiliation: Department of Orthopaedic Surgery, University of California San Francisco, San Francisco, CA, USA; Department of Mechanical Engineering, University of California Berkeley, Berkeley, CA, USA. Electronic address: FieldsA@orthosurg.ucsf.edu.
authors.forename: Aaron J
authors.initials: AJ
authors.lastname: Fields
authors.affiliation: Department of Mechanical Engineering, University of California Berkeley, Berkeley, CA, USA. Electronic address: arnavsanyal@berkeley.edu.
authors.forename: Arnav
authors.initials: A
authors.lastname: Sanyal
authors.affiliation: Bone Bioengineering Laboratory, Department of Biomedical Engineering, Columbia University, New York, NY, USA. Electronic address: xs2163@columbia.edu.
authors.forename: Xiutao
authors.initials: X
authors.lastname: Shi
authors.affiliation: Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY, USA. Electronic address: mark.adams@columbia.edu.
authors.forename: Mark
authors.initials: M
authors.lastname: Adams
authors.affiliation: Department of Mechanical Engineering, University of California Berkeley, Berkeley, CA, USA. Electronic address: tmk@me.berkeley.edu.
authors.forename: Tony M
authors.initials: TM
authors.lastname: Keaveny
authors.affiliation: Bone Bioengineering Laboratory, Department of Biomedical Engineering, Columbia University, New York, NY, USA. Electronic address: exg1@columbia.edu.
authors.forename: X Edward
authors.initials: XE
authors.lastname: Guo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density; D001842:Bone and Bones / Q000000981:diagnostic imaging / Q000473:pathology*; D055119:Elastic Modulus; D005260:Female; D005272:Femur Neck / Q000000981:diagnostic imaging; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D011312:Pressure; D012016:Reference Values; D013314:Stress, Mechanical; D055114:X-Ray Microtomography
keywords: Elastic modulus; Finite element; Individual trabecula segmentation; Microarchitecture; Plate and rod; Yield strength