膝关节假体约束度的影响因素分析  

Analysis of Influencing Factors of Knee Joint Prostheses Constraint

作　　者：张家振 翟豹 杨抒 孙嘉怿 郭亚娟 史新立 ZHANG Jiazhen;ZHAI Bao;YANG Shu;SUN Jiayi;GUO Yajuan;SHI Xinli(Center for Medical Device Evaluation,NMPA,Beijing 100076,China;GBA Center for Medical Device Evaluation and Inspection,NMPA,Guangdong Shenzhen 518045,China)

机构地区：[1]国家药品监督管理局医疗器械技术审评中心,北京100076 [2]国家药品监督管理局医疗器械技术审评检查大湾区分中心,广东深圳518045

出　　处：《中国医药导刊》2024年第12期1184-1191,共8页Chinese Journal of Medicinal Guide

摘　　要：人工膝关节假体设计需要在松弛性(低约束)和形合度之间取得平衡,既要减少关节面磨损,又要实现自然的关节运动模式。膝关节的股骨-胫骨关节面几何形状决定了在超高分子量聚乙烯衬垫表面产生的应力大小(进而影响关节面磨损)及其在活动周期中的滑动模式。增加股骨和胫骨关节面的形合度能够增加接触面积,减小接触应力,从而降低关节面磨损。但高形合度的关节面设计可能限制关节面相对运动,无法使股骨和胫骨组件以与自然膝关节相同的方式相对运动,导致假体与截骨面的固定界面承受较高的载荷从而引发假体松动。约束(constraint)是描述膝关节假体稳定性的术语,指当对全膝关节假体施加力和力矩时,股骨和胫骨部件关节面之间发生相对位移和旋转所受到的阻力。ASTM F1223标准描述了确定膝关节假体的前后剪切、内外侧剪切、内外轴向旋转、内外翻旋转约束度的测试方法,也可用于关节脱离约束度测试。本研究基于简化模型条件下的关节面运动约束受力分析,描述了力-位移曲线的形成过程,有利于理解某一特定关节面设计的约束度曲线特征,并进一步探讨了关节面设计(如曲率半径、形合度)、凸轮立柱机制设计、活动平台胫骨假体、关节面材料、关节面的表面粗糙度和润滑条件、加载条件等影响约束度曲线特征的因素,从而为假体设计改进以及临床医生选择合适约束度的假体提供参考。The design of artificial knee prostheses requires a balance between relaxation(low constraint)and conformity,in order to reduce joint surface wear and achieve natural joint movement patterns.The geometry of the femur-tibia joint surface determines the magnitude of the stresses generated on the ultra-high molecular weight polyethylene liner surface(and hence affect the joint surface wear)and its sliding pattern during the activity cycle.Increasing the conformity of the femur and tibia joint surfaces can increase the contact area and reduce contact stress,thereby reducing joint surface wear.However,a high degree of joint surface conformity may limit the relative motion of the joint surfaces,preventing the femur and tibia components from moving relative to each other in the same way as a natural knee joint and causing the interface between the prosthesis and the resection plane to bear higher loads and lead to prosthesis loosening.Constraint is a term used to describe the stability of knee joint prostheses,referring to the resistance to relative displacement and rotation of the femoral and tibial components joint surfaces when a full knee prosthesis is subjected to forces and moments.The ASTM F1223 standard describes the testing methods for determining the anterior-posterior shear,medial-lateral shear,internal-external rotation,and medial-lateral flexion-extension constraint of knee prostheses,and can also be used for testing the constraint of joint release.This article aims to describe the process of forming force-displacement curves based on joint surface motion constraint force analysis under simplified model conditions,which is helpful to understand the constraint curve features of a specific joint surface design,and further explored the factors that influencing the features of constraint curve,such as joint surface design(such as curvature radius,conformity),cam column mechanism design,mobilebearing tibial prosthesis,surface material,surface roughness,lubrication,and loading conditions,etc.,in order to provide

关 键 词：约束 关节面 测试标准 形合度 

分 类 号：R318.1[医药卫生—生物医学工程]