Age-related changes in trabecular bone microdamage initiation
Age-related changes in trabecular bone microdamage initiation
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DOI：
10.1016/j.bone.2006.10.028
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发表时间：
2007-04-01
期刊：
影响因子：
4.1
通讯作者：
Guldberg, Robert E.
中科院分区：
文献类型：
--
作者：
Nagaraja, Srinidhi;Lin, Angela S. P.;Guldberg, Robert E.
随着年龄的增长，骨质量、数量和微结构的改变影响骨小梁对局部失效的抵抗力。观察到骨折发生率随年龄呈指数增加，这些变化的临床意义显而易见。尽管骨骼脆性的年龄相关性发展已得到很好的证实，但骨的局部失效特性如何随年龄变化尚不清楚。我们以前曾报道过一种特定的技术来评估微结构应力和应变与微损伤的启动，但没有评估年龄相关的变化。在这项研究中，我们比较了年轻（平均年龄2岁）和老年（平均年龄10岁）牛骨小梁，以评估牛骨数量和质量随年龄的变化如何影响与微损伤形成相关的局部机械环境。结果表明，年轻和老年牛骨小梁的微损伤和局部应力和应变之间的强正相关性。通过将基于矿物密度的非均匀局部材料特性纳入有限元模型，某些参数的相关强度略有提高（< 8%）。在个体骨小梁内，与随机选择的未受损骨小梁相比，微损伤骨小梁的平均应力和应变显著更高，与年龄无关。然而，发现老年骨中受损的骨小梁比年轻骨中的骨小梁具有更高的应力和更低的应变。两组之间也观察到相应的矿物密度，微结构和有限元确定的局部材料特性的差异。总之，这些数据表明，在小梁水平的微损伤启动力学显着的年龄相关的变化。本研究中使用的实验、计算和组织化学相结合的方法提供了对微损伤启动和骨质量的更好理解。(c)2006年爱思唯尔公司All rights reserved.
With age, alterations occurring in bone quality, quantity, and microarchitecture affect the resistance of trabecular bone to local failure. The clinical implications of these changes are evident by the observed exponential increase in fracture incidence with age. Although age-related development of skeletal fragility is well established, it is unclear how the local failure properties of bone change with age. We previously reported a specimen-specific technique to assess microstructural stresses and strains associated with microdamage initiation but did not assess age-related changes. In this study, we compared younger (average age 2 years) and older (average age 10 years) bovine trabecular bone to evaluate how alterations in bovine bone quantity and quality with age affect the local mechanical environment associated with microdamage formation. The results show strong positive correlations between microdamage and local stresses and strains for both younger and older bovine trabecular bone. Correlation strength was slightly improved (< 8%) for some parameters by incorporating heterogeneous local material properties based on mineral density into the finite element models. Within individual trabeculae, average stresses and strains were significantly higher in microdamaged trabeculae compared to randomly selected undamaged trabeculae, regardless of age. However, damaged trabeculae in older bone were found to have higher stresses and lower strains than those from younger bone. Corresponding differences in mineral density, microarchitecture, and FEM-determined local material properties were also observed between the two groups. Taken together, these data suggest marked age-related changes in the mechanics of microdamage initiation at the trabecular level. The combined experimental, computational, and histochemical approaches used in this study provide an improved understanding of microdamage initiation and bone quality. (c) 2006 Elsevier Inc. All rights reserved.