Department of Mechanical Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK, S7N 5A9, Canada.
College of Kinesiology, University of Saskatchewan, 87 Campus Drive, Saskatoon, SK, S7N 0W6, Canada.
Sci Rep. 2024 Mar 25;14(1):7029. doi: 10.1038/s41598-024-57768-7.
Proximal femoral fractures are a serious life-threatening injury with high morbidity and mortality. Magnetic resonance (MR) imaging has potential to non-invasively assess proximal femoral bone strength in vivo through usage of finite element (FE) modelling (a technique referred to as MR-FE). To precisely assess bone strength, knowledge of measurement error associated with different MR-FE outcomes is needed. The objective of this study was to characterize the short-term in vivo precision errors of MR-FE outcomes (e.g., stress, strain, failure loads) of the proximal femur for fall and stance loading configurations using 13 participants (5 males and 8 females; median age: 27 years, range: 21-68), each scanned 3 times. MR-FE models were generated, and mean von Mises stress and strain as well as principal stress and strain were calculated for 3 regions of interest. Similarly, we calculated the failure loads to cause 5% of contiguous elements to fail according to the von Mises yield, Brittle Coulomb-Mohr, normal principal, and Hoffman stress and strain criteria. Precision (root-mean squared coefficient of variation) of the MR-FE outcomes ranged from 3.3% to 11.8% for stress and strain-based mechanical outcomes, and 5.8% to 9.0% for failure loads. These results provide evidence that MR-FE outcomes are a promising non-invasive technique for monitoring femoral strength in vivo.
股骨近端骨折是一种严重的危及生命的损伤，发病率和死亡率都很高。磁共振（MR）成像具有通过使用有限元（FE）建模（称为 MR-FE）无创评估体内股骨近端骨强度的潜力。为了准确评估骨强度，需要了解与不同 MR-FE 结果相关的测量误差。本研究的目的是使用 13 名参与者（5 名男性和 8 名女性；中位年龄：27 岁，范围：21-68 岁），每次扫描 3 次，对跌倒和站立加载配置下股骨近端的 MR-FE 结果（例如，应力、应变、失效载荷）的短期体内精密度误差进行特征描述。生成了 MR-FE 模型，并计算了 3 个感兴趣区域的平均 von Mises 应力和应变以及主应力和应变。同样，我们根据 von Mises 屈服、脆性库仑-摩尔、法向主应力和霍夫曼应力和应变准则计算了导致 5%连续元素失效的失效载荷。基于应力和应变的力学结果的 MR-FE 结果的精度（均方根变异系数）范围为 3.3%至 11.8%，失效载荷的精度范围为 5.8%至 9.0%。这些结果表明，MR-FE 结果是一种有前途的非侵入性技术，可用于监测体内股骨强度。
