Abstract: Background　The changes of the knee joint deformation，activity limitation，and gait abnormalities in knee osteoarthritis（ KOA ） indicates that KOA is a disease closely related to the biomechanical factors such as kinematics and kinematic mechanics.At present，there is no clinical quantitative index for evaluating these parameters of kinematics and kinematic mechanics.Objective　To analyze the condition of KOA patients by using the three-dimensional motion capture system in order to provide a new important reference for the development and implementation of the treatment and rehabilitation plan for clinicians.Methods　Ten bilateral KOA patients and 10 healthy people without KOA were recruited from Ruijin Hospital，Shanghai Jiaotong University School of Medicine during October 2010 to June 2017.The KOA patients and the healthy people were tested for walking using the British VICON 3D motion capture system and the walking situation and the biomechanical characteristics（ kinematics，dynamics ） of the knee joint were analyzed.Results　Compared with the healthy people，the KOA patients had the obvious gait and biomechanical characteristics，which showed the cadence，limp index，step length，stride length，and walking speed were shortened significantly，and the double support，single support，step time，and stride time were extended significantly（ P<0.05 ）.The knee flexion angle peak，the initial angle of the coronal knee joint，and the maximum range of motion of the knee joint in all three directions were decreased significantly（ P<0.05 ） ；the peak and average of knee joint angular velocity and knee joint angular acceleration were decreased significantly（ P<0.05 ） ；the knee joint extension torque peak were decreased significantly（ P<0.05 ）.The peak value of the floor reaction force in the Y-axis and Z-axis directions were decreased significantly（ P<0.05 ）.Conclusion　The biomechanical environment in and around the joints of KOA patients has changed significantly，and abnormal lower limb movements have occurred at the same time.The three-dimensional gait analysis of KOA patients and normal people using VICON motion capture system is helpful to better understand the parameters of knee joint kinematics and kinematic mechanics，which provides an important reference for the diagnosis，treatment and research of KOA.

Key words: Osteoarthritis, Three-dimensional motion analysis, Knee osteoarthritis, Gait analysis, Kinematics, Motion mechanics

摘要： 背景　膝骨关节炎（KOA）患者发生膝关节变形、活动受限、步态异常等改变，预示KOA是与运动学、动力学等生物力学因素关系密切的一种疾病。而目前临床上缺乏对这些运动学、动力学指标的客观定量评定指标。目的　应用VICON三维运动捕捉系统解析KOA患者的病情，为临床医生治疗、康复计划的制定和实施提供新的重要参考依据。方法　2010年10月—2017年6月，选择上海交通大学医学院附属瑞金医院门诊及住院的双KOA患者10例作为KOA组，另外招募无膝关节疼痛的健康中老年人10例作为对照组。采用英国VICON三维运动捕捉系统对两组受试者进行行走测试，并分析受试者的步行情况和膝关节的生物力学（运动学、动力学）特征。结果　与正常人比较，KOA患者存在明显的步态和生物力学特征：步频、跛行指数、步长、步幅、步速均缩短，双足支撑期、单足支撑期、一步时间、步行周期均延长（P<0.05）；膝关节屈曲角峰值，冠状面最初角度，矢状面、冠状面、水平面膝关节最大活动范围均减小（P<0.05）；膝关节角速度、膝关节角加速度峰值和平均值均减小（P<0.05）；膝关节伸展力矩峰值减小（P<0.05）；Y轴和Z轴方向地板反作用力峰值减小（P<0.05）。结论　KOA患者关节内及其周围生物力学环境发生了明显变化，同时下肢运动出现了异常。而采用VICON运动捕捉系统对KOA患者和正常人进行三维步态分析，有助于更好地了解膝关节运动学和动力学等指标，为KOA诊断、治疗及研究提供重要的参考依据。

关键词: 骨关节炎, 三维运动解析, 膝骨关节炎, 步态分析, 运动学, 动力学