个性化3D打印钛合金舟骨部分置换术后有限元模型的建立及生物力学分析

Establishment and biomechanical analysis of finite element model after partial replacement prosthesis of titanium alloy scaphoid with personalized 3D printing

目的建立腕关节三维有限元模型,研究个性化3D打印舟骨部分置换术后腕关节及假体在不同角度运动中的应力分布和形变,为假体设计与优化提供依据,为临床应用提供生物力学支持。方法导入1例左腕舟骨骨折伴骨缺失患者的腕关节CT数据及个性化3D打印钛合金舟骨部分置换假体数据,建立有限元模型,分析不同运动方向腕关节整体形变、应力分布及假体与螺钉应力分布。结果随运动角度增加,腕关节整体形变与应力均有所增大,但无明显应力集中区、应力遮蔽等问题。假体应力集中在舟骨连接处,极度掌屈时最大(264.45 MPa);螺钉应力集中在腰部,极度尺偏时最大(116.13MPa),均未超材料强度。结论个性化3D打印钛合金舟骨部分置换术后,腕关节整体形变小、应力分布合理,无过度集中或遮蔽问题,最大应力远低于材料屈服强度。该手术方式可匹配患者解剖特征,具有良好生物力学性能,是治疗腕舟骨骨不连伴骨坏死的合适选择。

Objective To establish a three-dimensional finite element model of the wrist joint and investigate the stress distribution and deformation of the wrist joint and prosthesis at different angles of motion after partial replacement prosthesis of scaphoid with personalized 3D printing,so as to provide basis for design and optimization of prosthesis for clinical application.Methods The CT data of the wrist joint of a patient with left scaphoid fracture and bone defect and the data of a personalized 3D-printed titanium alloy scaphoid prosthesis were imported into finite element analysis software.Relevant material properties were assigned.The overall deformation,stress distribution of the wrist joint,and stress distribution of the prosthesis and screws under different motion directions were analyzed.Results With the increasing of motion angle,the overall deformation and stress of the wrist joint increased correspondingly,but there were no obvious stress concentration and shielding.The stress of the prosthesis was concentrated at the scaphoid junction,reaching a maximum value during extreme palmar flexion(264.45 MPa),the stress of the screw was concentrated in the waist,reaching a maximum value during extreme ulnar deviation(116.13 MPa),but did not exceed the material strength.Conclusions After the partial replacement of the personalized 3D-printed titanium alloy scaphoid prosthesis,the overall deformation of the wrist joint was small,and the stress distribution was reasonable,without excessive concentration or shielding.The maximum stress was much lower than the yield strength of the prosthesis material.This surgical method can match the anatomical characteristics of the patient,has good biomechanical properties,and is a suitable choice for the treatment of scaphoid nonunion with osteonecrosis of the wrist.