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首页> 外文期刊>Journal of Biomechanics >The roles of architecture and estrogen depletion in microdamage risk in trabecular bone
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The roles of architecture and estrogen depletion in microdamage risk in trabecular bone

机译：结构和雌激素耗竭在小梁骨微损伤风险中的作用

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Bone quantity, or density, has insufficient power to discriminate fracture risk in individuals. Additional measures of bone quality, such as microarchitectural characteristics and bone tissue properties, including the presence of damage, may improve the diagnosis of fracture risk. Microdamage and microarchitecture are two aspects of trabecular bone quality that are interdependent, with several microarchitectural changes strongly correlated to damage risk after compensating for bone density. This study aimed to delineate the effects of microarchitecture and estrogen depletion on microdamage susceptibility in trabecular bone using an ovariectomized sheep model to mimic post-menopausal osteoporosis. The propensity for microdamage formation in trabecular bone of the distal femur was studied using a sequence of compressive and torsional overloads. Ovariectomy had only minor effects on the micro architecture at this anatomic site. Microdamage was correlated to bone volume fraction and structure model index (SMI), and ovariectomy increased the sensitivity to these parameters. The latter may be due to either increased resorption cavities acting as stress concentrations or to altered bone tissue properties. Pre-existing damage was also correlated to new damage formation. However, sequential loading primarily generated new cracks as opposed to propagating existing cracks, suggesting that pre-existing microdamage contributes to further damage of bone by shifting load bearing to previously undamaged trabeculae, which are subsequently damaged. The transition from plate-like to rod-like trabeculae, indicated by SMI, dictates this shift, and may be a hallmark of bone that is already predisposed to accruing greater levels of damage through compromised microarchitecture. (C) 2016 Elsevier Ltd. All rights reserved.
机译：骨量或密度不足以区分个体的骨折风险。额外的骨质测量指标，例如微结构特征和骨组织特性，包括损伤的存在，可以改善骨折风险的诊断。微损伤和微体系结构是小梁骨质量的两个相互依存的方面，在补偿骨密度后，一些微体系结构的变化与损伤风险密切相关。这项研究旨在使用去卵巢绵羊模型模拟绝经后骨质疏松症，描述微结构和雌激素耗竭对小梁骨微损伤敏感性的影响。使用一系列压缩和扭转过载研究了股骨远端小梁骨中微损伤形成的倾向。卵巢切除术对该解剖部位的微结构影响很小。微损伤与骨体积分数和结构模型指数（SMI）相关，卵巢切除术增加了对这些参数的敏感性。后者可能是由于增加的吸收腔起到了应力集中的作用，或者是由于改变了骨组织的特性。预先存在的损害也与新的损害形成有关。但是，顺序载荷主要产生新的裂纹，而不是扩展现有的裂纹，这表明预先存在的微损伤通过将承重转移到先前未损坏的小梁而进一步破坏了骨骼，随后这些小梁被破坏了。由SMI指示的从板状小梁到杆状小梁的过渡决定了这种转变，并且可能是骨骼的标志，骨骼已经倾向于通过受损的微结构而遭受更大程度的损伤。 （C）2016 Elsevier Ltd.保留所有权利。

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