Department of Mechanical Engineering, Villanova University, 800 Lancaster Avenue, Villanova, PA, USA.
J Biomech. 2013 Apr 26;46(7):1305-11. doi: 10.1016/j.jbiomech.2013.02.009. Epub 2013 Mar 13.
A new fracture assessment approach that combines HR-pQCT imaging with fracture mechanics-based finite element modeling was developed to evaluate distal radius fracture load. Twenty distal radius images obtained from postmenopausal women (fracture, n=10; nonfracture, n=10) were processed to obtain a cortical and a whole bone model for each subject. The geometrical properties of each model were evaluated and the corresponding fracture load was determined under realistic fall conditions using cohesive finite element modeling. The results showed that the whole bone fracture load can be estimated based on the cortical fracture load for nonfracture (R(2)=0.58, p=0.01) and pooled data (R(2)=0.48, p<0.001) but not for the fracture group. The portion of the whole bone fracture load carried by the cortical bone increased with increasing cortical fracture load (R(2)≥0.5, p<0.05) indicating that a more robust cortical bone carries a larger percentage of whole bone fracture load. Cortical thickness was found to be the best predictor of both cortical and whole bone fracture load for all groups (R(2) range: 0.49-0.96, p<0.02) with the exception of fracture group whole bone fracture load showing the predictive capability of cortical geometrical properties in determining whole bone fracture load. Fracture group whole bone fracture load was correlated with trabecular thickness (R(2)=0.4, p<0.05) whereas the nonfracture and the pooled group did not show any correlation with the trabecular parameters. In summary, this study introduced a new modeling approach that coupled HR-pQCT imaging with fracture mechanics-based finite element simulations, incorporated fracture toughness and realistic fall loading conditions in the models, and showed the significant contribution of the cortical compartment to the overall fracture load of bone. Our results provide more insight into the fracture process in bone and may lead to improved fracture load predictions.
一种新的骨折评估方法,结合高分辨率 CT 成像和基于断裂力学的有限元建模,用于评估桡骨远端骨折负荷。从绝经后妇女中获得 20 个桡骨远端图像(骨折,n=10;非骨折,n=10),对每个受试者的皮质骨和整个骨模型进行处理。评估每个模型的几何特性,并使用内聚有限元建模在现实的跌倒条件下确定相应的骨折负荷。结果表明,对于非骨折(R(2)=0.58,p=0.01)和汇总数据(R(2)=0.48,p<0.001),可以根据皮质骨折负荷估计整个骨骨折负荷,但不能用于骨折组。随着皮质骨折负荷的增加,整个骨骨折负荷由皮质骨承担的部分增加(R(2)≥0.5,p<0.05),这表明更坚固的皮质骨承载更大比例的整个骨骨折负荷。皮质厚度被发现是所有组的皮质和整个骨骨折负荷的最佳预测因子(R(2)范围:0.49-0.96,p<0.02),除了骨折组整个骨骨折负荷,皮质几何特性在确定整个骨骨折负荷方面具有预测能力。骨折组整个骨骨折负荷与骨小梁厚度相关(R(2)=0.4,p<0.05),而非骨折组和汇总组与骨小梁参数均无相关性。总之,本研究引入了一种新的建模方法,该方法将 HR-pQCT 成像与基于断裂力学的有限元模拟相结合,在模型中纳入了断裂韧性和现实的跌倒加载条件,并显示了皮质区室对骨整体骨折负荷的重要贡献。我们的结果提供了对骨骨折过程的更深入了解,可能会导致骨折负荷预测的改善。