Department of Kinesiology, Shanghai University of Sport, Shanghai, China.
Department of Orthopaedics, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, 510000, Guangdong, China.
J Orthop Surg Res. 2021 Jul 3;16(1):425. doi: 10.1186/s13018-021-02576-2.
The Opti_Knee system, a marker-based motion capture system, tracks and analyzes the 6 degrees of freedom (6DOF) motion of the knee joint. However, the validation of the accuracy of this gait system had not been previously reported. The objective of this study was to validate and the system. Two healthy subjects were recruited for the study.
The 6DOF kinematics of the knee during flexion-extension and level walking cycles of the knee were recorded by Opti_Knee and compared to those from a biplanar fluoroscopy system. The root mean square error (RMSE) of knee kinematics in flexion-extension cycles were compared between the two systems to validate the accuracy at which they detect basic knee motions. The RMSE of kinematics at key events of gait cycles (level walking) were compared to validate the accuracy at which the systems detect functional knee motion. Pearson correlation tests were conducted to assess similarities in knee kinematic trends between the two systems.
In flexion-extension cycles, the average translational accuracy (RMSE) was between 2.7 and 3.7 mm and the average rotational accuracy was between 1.7 and 3.8°. The Pearson correlation of coefficients for flexion-extension cycles was between 0.858 and 0.994 for translation and 0.995-0.999 for angles. In gait cycles, the RMSEs of angular knee kinematics were 2.3° for adduction/abduction, 3.2° for internal/external rotation, and 1.4° for flexion/extension. The RMSEs of translational kinematics were 4.2 mm for anterior/posterior translation, 3.3 mm for distal/proximal translation, and 3.2 mm for medial/lateral translation. The Pearson correlation of coefficients values was between 0.964 and 0.999 for angular kinematics and 0.883 and 0.938 for translational kinematics.
The Opti_Knee gait system exhibited acceptable accuracy and strong correlation strength compared to biplanar fluoroscopy. The Opti _Knee may serve as a promising portable clinical system for dynamic functional assessments of the knee.
Opti_Knee 系统是一种基于标记的运动捕捉系统，可跟踪和分析膝关节的 6 自由度（6DOF）运动。然而，该步态系统的准确性尚未得到验证。本研究的目的是验证该系统。招募了两名健康受试者进行研究。
通过 Opti_Knee 记录膝关节屈伸和水平步行周期的 6DOF 运动学，并与双平面荧光透视系统进行比较。比较两种系统在屈伸循环中检测基本膝关节运动的准确性，以比较膝关节运动学的均方根误差（RMSE）。比较步态周期关键事件（水平行走）的运动学 RMSE，以验证系统检测功能膝关节运动的准确性。进行 Pearson 相关测试，以评估两种系统之间膝关节运动学趋势的相似性。
在屈伸循环中，平均平移精度（RMSE）在 2.7 到 3.7mm 之间，平均旋转精度在 1.7 到 3.8°之间。屈伸循环的 Pearson 相关系数在 0.858 到 0.994 之间，用于平移，在 0.995 到 0.999 之间用于角度。在步态周期中，角运动学的 RMSE 为内收/外展 2.3°，内旋/外旋 3.2°，屈伸 1.4°。运动学的 RMSE 为前/后平移 4.2mm，远/近平移 3.3mm，内/外平移 3.2mm。角运动学的 Pearson 相关系数值在 0.964 到 0.999 之间，平移运动学的 Pearson 相关系数值在 0.883 到 0.938 之间。
与双平面荧光透视相比，Opti_Knee 步态系统具有可接受的准确性和较强的相关性。Opti_Knee 可能成为一种有前途的便携式临床系统，用于动态评估膝关节功能。
