背景：残肢-接受腔界面生物力学特性不仅对假肢的适配性有着直接影响，而且也是对接受腔结构进行优化设计的基础。将数字化设计技术与康复工程结合在一起，将有效地提髙假肢接受腔的制作效率和质量。

目的：采用逆正向结合的建模方法，对小腿截肢患者进行定制式的接受腔模型设计，评估残肢与接受腔的界面应力，对接受腔进行迭代设计，优化后的模型采用3D打印制作，以改善传统手工制作接受腔方法。

方法：选择2例内蒙古自治区荣誉军人肢残康复中心的小腿截肢志愿者，根据患者残肢的CT扫描图像，采用Mimics进行图像处理，然后经过Geomagic和UG逆向得到残肢的几何模型。通过使用计算机辅助设计软件Fusion360，根据残肢各个部位的组织结构不同的承受能力作为修型原理对接受腔进行正向建模设计。选用Mooney-Revlin超弹性模型定义软组织的材料特性，对残肢-接受腔界面应力进行有限元分析，并根据结果反馈指导对接受腔进行迭代设计，对再次修型后的接受腔模型进行评估。3D打印制作出接受腔，并进行实验测量。

结果与结论：①对迭代设计后的接受腔与残肢界面的应力进行分析，得到残肢各区域的应力值均低于疼痛阈值，符合设计标准，能较好实现功能传递性和安全舒适性；②此2例患者穿戴3D打印制作的接受腔适配性、稳定性良好，步行对称性相比手工制作接受腔均有显著改善，满足残肢生物力学要求；③试验建立了完整的假肢接受腔的设计、评估及制造系统。

BACKGROUND:Biomechanical properties of the residual limb-socket interface not only have a direct impact on the fit of the prosthesis,but also the basis for optimal design of the socket digital design technology with rehabilitation medical engineering will effectively improve the efficiency and quality of the prosthesis socket.

OBJECTIVE:The reverse-positive combined modeling method was used to design a custom-made socket model for patients with calf amputation to evaluate the interfacial stress between the residual limb and the socket was iteratively optimized model was produced by three-dimensional printing to improve traditional hand-made socket methods.

METHODS:Two patients with calf amputation were selected(Volunteers of the Inner Mongolia Honorary Military Rehabilitation Center).According to the CT scan image of the patient’s residual limb,Mimics was used for image processing,and then Geomagic and UG were used to obtain the geometric model of the residual the use of the computer-aided design software Fusion360,the socket was forward modeled according to the different tolerances of the tissue structure of the various parts of the residual limb.The Mooney-Revlin superelastic model was used to define the material properties of the soft tissue,and the finite element analysis of the residual limb-socket interface stress was iterative design of the socket was carried out according to the feedback of the results,and the acceptance socket model after re-modification was printing produced a socket,which received experimental measurements.

RESULTS AND CONCLUSION:(1)The stress of the interface between the socket and the residual limb after iterative design was analyzed,and the stress values of the residual limbs were lower than the pain threshold,which met the design standard and could achieve functional transferability and safety comfort.(2)Two patients wearing three-dimensional printing made the socket adaptability and stability,and the walking symmetry was significantly improved compared with the hand-made socket,meeting the biomechanical requirements of the residual limb.(3)A complete design,evaluation and manufacturing system for the prosthetic lumen was established.

0 引言 Introduction

通过计算机辅助设计及有限元分析可以在制作接受腔之前分析残肢与接受腔的界面应力，进而对接受腔进行评估，并改善设计[1-2]。对于如何加快假肢接受腔的设计制造速度，提高接受腔的质量，定量评价假肢的舒适度等方面，主要的研究方法可分为实验测量和有限元仿真[3-8]。

ZACHARIAH等[9]提出了一种自动接触方法，通过自动检测界面节点的所有重叠区域，并对重叠节点施加非穿透条件约束来模拟接触。然而，这项研究没有模拟残肢穿戴修型后的接受腔过程中产生的预应力。

一些研究证明了通过计算机集成CAD和FEA设计接受腔的可行性[10]。PENG等[11]将经过有限元分析验证的接受腔模型导入到3D打印机制作得到假肢接受腔，然后涂上一层树脂以增强抗弯强度，并测量了患者穿上假肢并在力平台上行走时的界面压力分布，将这种新型接受腔和传统接受腔之间的界面压力的结果进行了比较，发现这种新型接受腔在髌韧带处可以承受更高的压力。该研究证明了在不使用石膏的情况下制造RP接受腔的可行性，并且可以存储接受腔的相关信息以供进一步使用。