Effect of cortical bone micro-structure in fragility fracture patients on lamellar stress
Effect of cortical bone micro-structure in fragility fracture patients on lamellar stress
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DOI：
10.1016/j.jbiomech.2019.109596
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发表时间：
2020-02-13
影响因子：
2.4
通讯作者：
Keyak, Joyce H.
中科院分区：
文献类型：
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作者：
Ascenzi, Maria-Grazia;Zonca, Andrea;Keyak, Joyce H.
这项工作研究了皮质骨微结构的变化如何改变脆性骨折的风险。非骨质疏松（DXA）女性脆性骨折的继发性骨单位在横切面上具有减少的板层宽度和更大的双折射亮度区域，这是一种病理状态。我们使用分层有限元（FE）模型的股骨近端的两名妇女，年龄分别为67岁和88岁（年轻和老年）在单腿站立。在前下颈部（ROI）的特定位置，我们分析了包含骨单位的微模型，骨单位由交替的双折射消光和亮板组成。板层各向同性平面（XY）横向于骨单位纵轴（Z），骨单位纵轴平行于股骨颈轴。为了评估断裂风险随微观结构变化的变化，我们研究了主应力和冯米塞斯应力，以及占横向各向同性的平面应力措施。对于年轻和老年股骨，48%至100%的应力措施是更大的模型与健康的架构比模型与病理结构，同时控制类型的板层和骨单位。这些发现表明，骨适应减少应力在大多数病理板层网站。然而，在明亮的薄层的年轻股骨，病理拉伸，压缩和扭曲应力在横向平面和扭曲应力在纵向平面大于不可忽略的相应的应力在6/28骨模型与健康的建筑，在5/7的位置。因此，少数具有病理结构的部位存在更大的应力，因此，更大的骨折风险。(C)2019爱思唯尔有限公司版权所有。
This work investigates how changes in cortical bone microstructure alter the risk of fragility fractures. The secondary osteons of non-osteoporotic (by DXA) women with fragility fractures have reduced lamellar width and greater areas of birefringent brightness in transverse sections, a pathological condition. We used hierarchical finite element (FE) models of the proximal femur of two women aged 67 and 88 (younger and older) during one-legged stance. At specific locations of the anterior-inferior neck (ROI), we analyzed micro-models containing osteons comprised of alternating birefringent extinct and bright lamellae. The plane of lamellar isotropy (XY) was transverse to the osteon longitudinal axis (Z) which was parallel to the femoral neck axis. To evaluate changes in fracture risk with changes in microstructure, we investigated principal and von Mises stresses, and planar stress measures that accounted for transverse isotropy. For both younger and older femurs, 48% to 100% of stress measures were larger in models with healthy architecture than in models with pathological architecture, while controlling for type of lamella and osteon. These findings suggest that bone adaptation reduces stress at most pathological lamellar sites. However, in the bright lamellae of the younger femur, the pathological tensile, compressive and distortional stresses in the transverse plane and distortional stress in the longitudinal planes were larger than the non-negligible corresponding stresses in 6 of the 28 osteon models with healthy architecture, in 5 of the 7 locations. Therefore, a minority of sites with pathological architecture present greater stress, and therefore, greater fracture risk. (C) 2019 Elsevier Ltd. All rights reserved.