人体膝关节股胫关节运动特性分析

目的　分析人体正常膝关节和人工膝关节高屈曲活动下股胫关节的运动，为膝关节运动特性研究、假体设计提供参考。 方法　选取健康志愿者，利用CT和MRI扫描数据建立正常全膝关节三维有限元模型以及TKA术后有限元模型，采取三束股四头肌肌力非同步变力加载，模拟人体下蹲运动，以分析股胫关节的相对运动特性，并检索相关研究结果以便对比分析。 结果　获得正常膝关节以及TKA术后人体下蹲过程中股骨相对胫骨的三维相对运动数据，结果表明，TKA术前、后股胫关节相对运动的总体趋势相近，同时在前后位移、远近位移、内外位移、内收外展和内外旋等最大值方面存在差异；同时通过对比分析TKA前后股胫关节相对运动以及相关文献数据，发现结果存在不同程度差异。 结论　究其原因,正常膝关节相对运动差异主要在于股胫关节各个运动方向上和不同屈曲度时约束程度的改变；人工膝关节相对运动差异主要来源于膝关节型面和结构的改变；同时与坐标系的定义、在体和离体的差异、负荷加载的差异相关。本研究针对人体正常膝关节和TKA术后膝关节股胫关节运动进行有限元仿真分析，对膝关节运动特性研究具有一定的参考价值。

The high flexion kinematic characteristics research of Human tibiofemoral joint

Objective 　Analyzing the femorotibial (FT) joint kinematics of natural and artificial knees under high flexion behaviors provides a reference for the study of kinematic characteristics of knees and the prosthesis design.　Method　On the basis of the CT and MRI scanning data of healthy volunteers， dynamic finite element models (FEMs) of the human knee joint and total knee arthroplasty (TKA) were established. Through the loaded three-dimensional quadriceps asynchronous variable forces to simulation of the squatting exercise, our study analyzed the relative kinematic characteristics of FT articulation. Data in the relevant literature were retrieved and compared with our study for analyses. Result Three-dimensional kinematicsdata of the femur relative to the tibia of human’s natural and TKA knees were obtained during the squatting.The results showed that the overall trends of the relative kinematics of the femorotibial articulation before and after TKA were similar. However, the maximums of the kinetic aspects in the anterior or posterior translation,proximal or distal translation, medial or lateral translation, adduction or abduction rotation,and internal or external rotation were different. Our study found varying degrees of differences in the results through analyzing the relative kinematics of intact and TKA knees’ FT articulation and the existing relevant literature data.　Conclusions 　The main differences for nature knee relative kinematics are the changes in the level of restraints on the directions and the shifted flexion degrees of the knees’ FT joints.The differences for the TKA knee derive mainly from the knee-surface and structural changes; andboth of these differences are related to the definition of the coordinate system, in vitro or in vivo, and the various loads. This study has performed finite element simulation analyses for the kinematics of intact and TKA knees’ FT articulations , offering certain valuable references on the study of the knee kinematics.