股骨头内松质骨空间分布和力学性能变化有限元分析

Finite element study on spatial distribution and mechanical properties of cancellous bone from femoral head

目的应用有限元方法研究不同加载强度和偏轴角对股骨头内松质骨空间分布和力学性能变化的影响。方法基于断层磨削后扫描、计算机三维重建的方法建立得到股骨近端骨结构三维模型,按照与主压力小梁方向成0°、15°、45°分别选取相同大小的松质骨试件。计算试件的三维空间结构参数,应用有限元分析方法模拟单轴压缩试验,观察松质骨试件应力、应变分布,探讨不同加载强度和离轴角度对松质骨生物力学性质的影响。结果基于建立的人股骨头内松质骨三维有限元模型,模拟了松质骨试件单轴压缩试验,发现不同加载强度和偏轴角度在松质骨试件中≥5 000με(微应变)的松质骨比例存在统计学差异(P<0.05)。结论股骨头内松质骨小梁空间分布与力学适应性密切相关。结构与功能的不相适应降低了股骨头内部松质骨的生物力学性能,反复不良刺激引起的骨重塑、改建可能在股骨头坏死中起着重要的作用。

Objective To study the effect of different loading intensity and off-axis angle on changes in spatial dis-tribution and mechanical properties of cancellous bone from femoral head by using three-dimensional（3D） finite element method.Method The same size cancellous bone specimens were selected in accordance with the main pressure trabecular direction at 0°,15°and 45° off-axis angle from 3D model of proximal femoral bone struc-ture based on primary study.The 3D structure parameters of the specimen were calculated,then the finite ele-ment analysis was used to simulate the uniaxial compression test,and the stress and strain distribution in different model was observed.The influences of different loading intensity and off-axis angle on biomechanical properties of proximal femoral cancellous bone were investigated.Results Based on the established finite element model of cancellous bone of human femoral head,the uniaxial compression test was simulated.It was found that there were significant differences in the proportion of cancellous bone with ≥5 000μ strain in different mechanical strength or off-axis angle on cancellous bone specimens（P 0.05）.Conclusions Distribution of femoral head cancellous bone is closely related with the mechanical adaptability.The incompatibility between structure and function decreased the biomechanical properties of femoral head cancellous bone and the subsequent bone re-modeling caused by repeated negative stimulus may play an important role in femoral head necrosis.