Load distribution in the healthy and osteoporotic human proximal femur during a fall to the side
Load distribution in the healthy and osteoporotic human proximal femur during a fall to the side
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DOI：
10.1016/j.bone.2007.08.039
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发表时间：
2008-01-01
期刊：
影响因子：
4.1
通讯作者：
Huiskes, R.
中科院分区：
文献类型：
--
作者：
Verhulp, E.;van Rietbergen, B.;Huiskes, R.
由于骨结构的重塑，创造了一个最佳的结构，使骨量最小化，强度最大化。然而，在骨质疏松的椎体中，这个过程会产生过度适应，使它们容易受到非习惯性负荷的影响。在最近的一项研究中，对健康和骨质疏松的人股骨近端进行了站立阶段步态的微有限元模型分析。在本研究中，用相同的股骨近端微有限元模型计算了组织应力和应变，以模拟向侧面跌落到大转子上。我们的具体目的是确定小梁骨对这种非习惯性负荷下股骨近端强度的贡献。此外，我们验证了骨质疏松症骨的小梁结构过度适应习惯性负荷的假设。为此，我们计算了荷载分布，并从线性分析中估计了表观屈服和极限荷载。为此目的使用了两种不同的方法，结果非常相似，都在一个现实的范围内。最大主应变和有效应变在整个模型中的分布表明，骨小梁和骨皮质结构对骨强度的贡献是相似的。然而，厚的皮质壳优于致密的股骨颈小梁核心。当施加在骨质疏松股骨上的负荷减少到原始值的约61%时，所产生的应变分布与健康股骨的应变分布相似。由于在习惯性负荷病例中发现了可比的减少因子，因此得出结论，骨质疏松的股骨并没有“过度适应”。(C) 2007爱思唯尔公司版权所有。
Due to remodeling of bone architecture, an optimal structure is created that minimizes bone mass and maximizes strength. In the case of osteoporotic vertebral bodies, however, this process can create over-adaptation, making them vulnerable for non-habitual loads. In a recent study, micro-finite element models of a healthy and an osteoporotic human proximal femur were analyzed for the stance phase of gait. In the present study, tissue stresses and strains were calculated with the same proximal femur micro-finite element models for a simulated fall to the side onto the greater trochanter. Our specific objectives were to determine the contribution of trabecular bone to the strength of the proximal femurs for this non-habitual load. Further, we tested the hypothesis that the trabecular structure of osteoporotic bone is over-adapted to habitual loads. For that purpose, we calculated the load distributions and estimated the apparent yield and ultimate loads from linear analyses. Two different methods were used for this purpose, which resulted in very similar values, all in a realistic range. Distributions of maximal principal strain and effective strain in the entire model suggest that the contributions to bone strength of the trabecular and cortical structures are similar. However, a thick cortical shell is preferred over a dense trabecular core in the femoral neck. When the load applied to the osteoporotic femur was reduced to approximately 61% of the original value, strain distributions were created similar in value to those obtained for the healthy femur. Since a comparable reduction factor was found for habitual load cases, it was concluded that the osteoporotic femur was not 'over-adapted'. (C) 2007 Elsevier Inc. All rights reserved.