title: HR-pQCT-based homogenised finite element models provide quantitative predictions of experimental vertebral body stiffness and strength with the same accuracy as μFE models.
abstract: This study validated two different high-resolution peripheral quantitative computer tomography (HR-pQCT)-based finite element (FE) approaches, enhanced homogenised continuum-level (hFE) and micro-finite element (μFE) models, by comparing them with compression test results of vertebral body sections. Thirty-five vertebral body sections were prepared by removing endplates and posterior elements, scanned with HR-pQCT and tested in compression up to failure. Linear hFE and μFE models were created from segmented and grey-level CT images, and apparent model stiffness values were compared with experimental stiffness as well as strength results. Experimental and numerical apparent elastic properties based on grey-level/segmented CT images (N=35) correlated well for μFE (r2=0.748/0.842) and hFE models (r2=0.741/0.864). Vertebral section stiffness values from the linear μFE/hFE models estimated experimental ultimate apparent strength very well (r2=0.920/0.927). Calibrated hFE models were able to predict quantitatively apparent stiffness with the same accuracy as μFE models. However, hFE models needed no back-calculation of a tissue modulus or any kind of fitting and were computationally much cheaper.
authors.affiliation: Institute of Lightweight Design and Structural Biomechanics, Gusshausstrasse 27-29, 1040, Vienna, Austria. pahr@ilsb.tuwien.ac.at
authors.forename: Dieter H
authors.initials: DH
authors.lastname: Pahr
authors.forename: Enrico
authors.initials: E
authors.lastname: Dall'Ara
authors.forename: Peter
authors.initials: P
authors.lastname: Varga
authors.forename: Philippe K
authors.initials: PK
authors.lastname: Zysset
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D015519:Bone Density; D002102:Cadaver; D019245:Compressive Strength / Q000502:physiology; D004548:Elasticity / Q000502:physiology; D005260:Female; D020342:Finite Element Analysis; D006801:Humans; D066298:In Vitro Techniques; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D013131:Spine / Q000000981:diagnostic imaging / Q000502:physiology*; D014057:Tomography, X-Ray Computed