title: Change of mechanical vertebrae properties due to progressive osteoporosis: combined biomechanical and finite-element analysis within a rat model.
abstract: For assessing mechanical properties of osteoporotic bone, biomechanical testing combined with in silico modeling plays a key role. The present study focuses on microscopic mechanical bone properties in a rat model of postmenopausal osteoporosis. Female Sprague-Dawley rats were (1) euthanized without prior interventions, (2) sham-operated, and (3) subjected to ovariectomy combined with a multi-deficiencies diet. Rat vertebrae (corpora vertebrae) were imaged by micro-CT, their stiffness was determined by compression tests, and load-induced stress states as well as property changes due to the treatment were analyzed by finite-element modeling. By comparing vertebra stiffness measurements with finite-element calculations of stiffness, an overall microscopic Young's modulus of the bone was determined. Macroscopic vertebra stiffness as well as the microscopic modulus diminish with progression of osteoporosis by about 70 %. After strong initial changes of bone morphology, further decrease in macroscopic stiffness is largely due to decreasing microscopic Young's modulus. The micromechanical stress calculations reveal particularly loaded vertebra regions prone to failure. Osteoporosis-induced changes of the microscopic Young's modulus alter the fracture behavior of bone, may influence bone remodeling, and should be considered in the design of implant materials.
authors: Institute for Materials Science and Max Bergmann Center of Biomaterials, Dresden University of Technology, 01062, Dresden, Germany, robert.mueller@tu-dresden.de.
authors: Robert
authors: R
authors: Müller
authors: Marian
authors: M
authors: Kampschulte
authors: Thaqif El
authors: TE
authors: Khassawna
authors: Gudrun
authors: G
authors: Schlewitz
authors: Britta
authors: B
authors: Hürter
authors: Wolfgang
authors: W
authors: Böcker
authors: Manfred
authors: M
authors: Bobeth
authors: Alexander C
authors: AC
authors: Langheinrich
authors: Christian
authors: C
authors: Heiss
authors: Andreas
authors: A
authors: Deutsch
authors: Gianaurelio
authors: G
authors: Cuniberti
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena / Q000502:physiology*; D019245:Compressive Strength; D055119:Elastic Modulus; D005260:Female; D020342:Finite Element Analysis; D010024:Osteoporosis / Q000000981:diagnostic imaging / Q000503:physiopathology*; D010052:Ovariectomy; D011859:Radiography; D051381:Rats; D017207:Rats, Sprague-Dawley; D013131:Spine / Q000000981:diagnostic imaging / Q000503:physiopathology*