基于3D打印的胫骨骨折外固定生物力学研究

Biomechanical study on external fixation of tibial fractures based on 3D printing

利用逆向工程与3D打印技术定制了患者的胫骨干骨折模型,对Orthofix单边外固定器固定胫骨干骨折方式的生物力学进行了研究。通过设计正交试验方案,采用XTDIC三维全场变形测量系统对Schanz钉在针夹上的分布、最外侧Schanz钉到骨折断端的距离、胫骨到外固定器的距离三种因素对Schanz钉的变形进行了测量。实验结果表明:当Schanz钉数量较少时,在压力载荷作用下会造成Schanz钉的弯曲变形增大,增加了外固定器塑性变形及疲劳断裂的可能性。根据综合九种方案的力学分析结果,外固定器到胫骨的距离对Schanz钉的变形影响最显著。当在针夹上安装6根Schanz钉,外侧Schanz钉到骨折断端的距离为120 mm和外固定器到胫骨的距离为30 mm时的方案综合性能最优。

The tibial shaft fracture model was customized by reverse engineering and 3D printing technology,and the biomechanics of the Orthofix Unilateral External Fixator for tibial shaft fracture was studied.Through the design of an orthogonal experiment scheme,the distribution of the Schanz’s nails on the clamp,the distance from the lateral the Schanz’s nails to the fracture end,and the distance from the tibia to the external fixture were measured by the XTDIC-CONST 3D Full-Field Strain Measurement and Analysis System.The experimental results show that when the number of the Schanz’s nails decreased,the bending deformation of the Schanz’s nails will increase from pressure load,which increases the possibility of plastic deformation and fatigue fracture of the external fixator.Ac-cording to the mechanical analysis results of the nine schemes,the distance from the external fixture to the tibia has the most significant effect on the deformation of the Schanz nail.When installing six Schanz pins in the clip,the distance from the lateral Schanz’s nail to the fracture end is 120 mm,and the distance from the external fixture to the tibia is 30 mm.The comprehensive performance of the scheme is the best.