Kadaba M P, Ramakrishnan H K, Wootten M E
Orthopaedic Engineering and Research Center, Helen Hayes Hospital, West Haverstraw, NY 10993.
J Orthop Res. 1990 May;8(3):383-92. doi: 10.1002/jor.1100080310.
A simple external marker system and algorithms for computing lower extremity joint angle motion during level walking were developed and implemented on a computer-aided video motion analysis system (VICON). The concept of embedded axes and Euler rotation angles was used to define the three-dimensional joint angle motion based on a set of body surface markers. Gait analysis was performed on 40 normal young adults three times on three different test days at least 1 week apart using the marker system. Angular motion of the hip, knee, and ankle joints and of the pelvis were obtained throughout a gait cycle utilizing the three-dimensional trajectories of markers. The effect of uncertainties in defining the embedded axis on joint angles was demonstrated using sensitivity analysis. The errors in the estimation of joint angle motion were quantified with respect to the degree of error in the construction of embedded axes. The limitations of the model and the marker system in evaluating pathologic gait are discussed. The relatively small number of body surface markers used in the system render it easy to implement for use in routine clinical gait evaluations. Additionally, data presented in this paper should be a useful reference for describing and comparing pathologic gait patterns.
开发了一种简单的外部标记系统和算法，用于在水平行走过程中计算下肢关节角度运动，并在计算机辅助视频运动分析系统（VICON）上实现。基于一组体表标记，利用嵌入轴和欧拉旋转角的概念来定义三维关节角度运动。使用该标记系统，在至少相隔1周的三个不同测试日，对40名正常年轻成年人进行了三次步态分析。利用标记的三维轨迹，在整个步态周期中获取髋关节、膝关节、踝关节和骨盆的角运动。通过敏感性分析，证明了定义嵌入轴时的不确定性对关节角度的影响。根据嵌入轴构建中的误差程度，对关节角度运动估计中的误差进行了量化。讨论了该模型和标记系统在评估病理性步态方面的局限性。该系统使用的体表标记数量相对较少，便于在常规临床步态评估中实施。此外，本文提供的数据对于描述和比较病理性步态模式应是一个有用的参考。
