Bessho Masahiko, Ohnishi Isao, Matsuyama Juntaro, Matsumoto Takuya, Imai Kazuhiro, Nakamura Kozo
The Department of Orthopaedic Surgery, Faculty of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
J Biomech. 2007;40(8):1745-53. doi: 10.1016/j.jbiomech.2006.08.003. Epub 2006 Oct 10.
Hip fractures are the most serious complication of osteoporosis and have been recognized as a major public health problem. In elderly persons, hip fractures occur as a result of increased fragility of the proximal femur due to osteoporosis. It is essential to precisely quantify the strength of the proximal femur in order to estimate the fracture risk and plan preventive interventions. CT-based finite element analysis could possibly achieve precise assessment of the strength of the proximal femur. The purpose of this study was to create a simulation model that could accurately predict the strength and surface strains of the proximal femur using a CT-based finite element method and to verify the accuracy of our model by load testing using fresh frozen cadaver specimens. Eleven right femora were collected. The axial CT scans of the proximal femora were obtained with a calibration phantom, from which the 3D finite element models were constructed. Materially nonlinear finite element analyses were performed. The yield and fracture loads were calculated, while the sites where elements failed and the distributions of the principal strains were determined. The strain gauges were attached to the proximal femoral surfaces. A quasi-static compression test of each femur was conducted. The yield loads, fracture loads and principal strains of the prediction significantly correlated with those measured (r=0.941, 0.979, 0.963). Finite element analysis showed that the solid elements and shell elements in undergoing compressive failure were at the same subcapital region as the experimental fracture site.
髋部骨折是骨质疏松症最严重的并发症，已被公认为一个重大的公共卫生问题。在老年人中，髋部骨折是由于骨质疏松导致股骨近端脆性增加所致。精确量化股骨近端的强度对于评估骨折风险和制定预防干预措施至关重要。基于CT的有限元分析可能实现对股骨近端强度的精确评估。本研究的目的是使用基于CT的有限元方法创建一个能够准确预测股骨近端强度和表面应变的模拟模型，并通过使用新鲜冷冻尸体标本进行载荷测试来验证我们模型的准确性。收集了11根右侧股骨。使用校准体模获得股骨近端的轴向CT扫描图像，从中构建三维有限元模型。进行了材料非线性有限元分析。计算屈服载荷和断裂载荷，同时确定单元失效的部位和主应变的分布。将应变片粘贴在股骨近端表面。对每根股骨进行准静态压缩试验。预测的屈服载荷、断裂载荷和主应变与测量值显著相关（r=0.941、0.979、0.963）。有限元分析表明，受压失效的实体单元和壳单元与实验性骨折部位位于相同的股骨颈下区域。
