Finite element analysis of the mouse tibia: Estimating endocortical strain during three-point bending in SAMP6 osteoporotic mice
Finite element analysis of the mouse tibia: Estimating endocortical strain during three-point bending in SAMP6 osteoporotic mice
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DOI：
10.1002/ar.a.20171
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发表时间：
2005-04-01
期刊：
影响因子：
--
通讯作者：
Hucker, WJ
中科院分区：
文献类型：
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作者：
Silva, MJ;Brodt, MD;Hucker, WJ
为了支持老年性骨质疏松症(SAMP6)小鼠模型胫骨弯曲的未来研究，我们试图确定SAMP6和对照SAMR1小鼠胫骨施加的外部弯曲力与最大皮质内应变之间的关系。在支撑长度为10 mm的外侧-内侧平面上以三点弯曲的方式加载小鼠的后肢。力-骨膜应变关系首先用标准应变计方法测定。基于微型计算机断层扫描图像，建立了胫腓骨的有限元分析模型。在选择适当的边界条件后，骨膜应变的有限元预测值在实测值的15%以内。有限元分析显示胫骨中部有一个狭窄(3-4 mm)的区域，弯曲应变非常发达(内侧拉伸，外侧压缩)；在这个区域之外，我们观察到高剪切应变。应变片数据和有限元模拟都表明，SAMP6小鼠的胫骨比SAMR1小鼠的胫骨僵硬20%-25%，这与更大的惯性矩和更高的皮质骨弹性系数一致。因此，需要更高水平的力才能在SAMP6胫骨中产生相同的应变目标值。两个品系的小鼠感兴趣区域的骨膜与皮质内应变的比率相似(1.5-1.6)。基于这些比率，我们对应变计数据进行了缩放，以估计两个小鼠品系的力-皮质内应变关系。总而言之，有限元分析结合应变计测量，提供了关于小鼠三点弯曲时整个胫骨的应变环境的独特见解。(C)2005年Wiley-Liss，Inc.
To support future studies of tibial bending in a murine model of senile osteoporosis (SAMP6), we sought to determine the relationship between applied external bending force and peak endocortical strain in the tibiae of SAMP6 and control SAMR1 mice. The lower hindlimbs of mice were loaded by three-point bending in the lateral-medial plane with a support length of 10 mm. Force-periosteal strain relations were first determined using standard strain gauge methods. Finite-element analysis (FEA) models of the tibia-fibula were generated based on microcomputed tomography images. After choosing appropriate boundary conditions, FEA predictions of periosteal strains were within 15% of measured values. FEA revealed a narrow (3-4 mm) region of the central tibia with well-developed bending strains (tension medially, compression laterally); outside this region, we observed high shear strains. Both the strain gauge data and the finite-element simulations indicated that the tibia of the SAMP6 mouse was 20-25% stiffer than the SAMR1 tibia, consistent with a larger moment of inertia and higher cortical bone modulus. Thus, higher levels of force are required to produce the same target values of strain in the SAMP6 tibia. The ratio of periosteal to endocortical strain in the region of interest was similar for the two mouse strains (1.5-1.6). Based on these ratios, we scaled the strain gauge data to estimate the force-endocortical strain relations for the two mouse strains. In conclusion, FEA, with supporting strain gauge measurements, has provided unique insight regarding the strain environment throughout the tibia during three-point bending in mice. (c) 2005 Wiley-Liss, Inc.