不同力学激励对骨重建数值模拟的影响

The effect of different mechanical stimuli on numerical simulation of bone remodeling

目的研究采用应变能密度、等效应力、等效应变3种不同力学激励对骨重建数值模拟结果的影响。方法建立股骨近端的二维有限元模型,基于力学稳态理论的重建控制方程并结合有限元法,分别用3种不同力学激励模拟股骨近端的内部结构及密度分布,并与CT数据计算得到的骨密度值进行定量分析比较。结果 3种力学激励模拟得到的重建结果均能反映出股骨近端的主要特征结构,但采用等效应力作为激励时得到的股骨密度曲线图的趋势和数值都与CT图像数据更为一致。结论在骨重建力学调控机制中,应力可能起主导作用。准确预测和模拟骨重建过程将对矫形外科、骨伤治疗、人工假体的优化和个体化设计等临床实践提供理论依据。

Objective To study the effect of three different kinds of mechanical stimuli （i. e. strain energy density, equivalent stress and equivalent strain） on numerical simulation of bone remodeling. Methods A two-dimension- al finite element model of the proximal femur was constructed. Based on the mechanostat theory and finite ele- ment method, the inner structure of the proximal femur and its density distributions under the three different stimu- li were predicted. Then the simulation results were compared quantitatively with calculation results obtained from CT images. Results The predicted density distributions on the proximal femur under different stimuli were all well matched with the real structure of the proximal femur. By comparing the values and shapes of the calculated bone density curves, the predictions from the model using equivalent stress as mechanical stimuli were mostly consist- ent with the CT images. Conclusions The equivalent stress might play a leading role in mechano-regulation algo- rithms of bone remodeling. The accurate prediction of bone remodeling process will provide a theoretical basis for clinical practices such as orthopedic surgery, treatment of bone diseases and personalized design and optimiza- tion of prosthesis.