Duprey Sonia, Bruyere Karine, Verriest Jean-Pierre
LBMC-Biomechanics and Impact Mechanics Laboratory (UMR-T 9406 INRETS/UCBL), Case 24, 25 av. F Mitterrand, 69675 Bron, France.
J Biomech. 2008;41(1):200-7. doi: 10.1016/j.jbiomech.2007.06.020. Epub 2007 Aug 13.
Finite element body models enable the evaluation of car occupant protection. In general, these models represent average males and inter-individual geometry variability is not taken into account. As the most frequent shoulder injury during car lateral accidents is a clavicle fracture, the purpose of this study is to investigate whether clavicle geometry has an influence on bone response until failure, and whether geometrical personalization of clavicle models is required. Eighteen clavicles from 9 subjects (5 males and 4 females, mean age: 76 +/- 12 years) were harvested. Six clavicles were scanned, enabling the development of subject-specific models and the quantification of geometrical features defining shape and cortical thickness. Bone mineral densities (BMD) were measured through double X-ray absorptiometry. Then, the general clavicle responses to dynamic compression until failure were studied. Simulations of the compression tests were carried out with the subject-specific models to assess the sensitivity of force-deflection clavicle responses to geometrical features. Clavicle fractures occurred at an average velocity of 1.41 +/- 0.4 ms(-1), with a fracture force of 1.48 +/- 0.46 kN and a deflection of 5.4 +/- 1.1 mm. A significant difference was found between male and female clavicle force values at rupture although their BMDs were not significantly different. Simulations with subject-specific models led to the conclusion that cortical bone thickness and bone shape have large effects on bone responses until failure and on fracture location. This study highlights the need for a geometrical personalization of clavicle models in order to take into account both gender discrepancies concerning clavicle shape and aging effects affecting cortical thickness.
有限元人体模型有助于评估汽车乘员保护情况。一般来说，这些模型代表的是平均体型的男性，并未考虑个体间的几何形状差异。由于汽车侧面碰撞事故中最常见的肩部损伤是锁骨骨折，本研究的目的是调查锁骨几何形状是否会对骨折前的骨骼反应产生影响，以及是否需要对锁骨模型进行几何形状个性化处理。从9名受试者（5名男性和4名女性，平均年龄：76±12岁）身上采集了18根锁骨。对6根锁骨进行了扫描，从而能够开发出针对个体的模型，并对定义形状和皮质厚度的几何特征进行量化。通过双能X线吸收法测量骨密度（BMD）。然后，研究了一般锁骨在动态压缩直至骨折时的反应。使用针对个体的模型对压缩试验进行模拟，以评估力-位移锁骨反应对几何特征的敏感性。锁骨骨折发生时的平均速度为1.41±0.4米/秒，骨折力为1.48±0.46千牛，位移为5.4±1.1毫米。尽管男性和女性的骨密度没有显著差异，但在断裂时锁骨的受力值存在显著差异。使用针对个体的模型进行模拟得出的结论是，皮质骨厚度和骨骼形状对骨折前的骨骼反应以及骨折位置有很大影响。本研究强调了对锁骨模型进行几何形状个性化处理的必要性，以便考虑到锁骨形状方面的性别差异以及影响皮质厚度的老化效应。
