Atarod Mohammad, Rosvold Joshua M, Frank Cyril B, Shrive Nigel G
McCaig Institute for Bone and Joint Health, Faculty of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada,
Ann Biomed Eng. 2014 May;42(5):1121-32. doi: 10.1007/s10439-014-0985-9. Epub 2014 Feb 12.
Assessing joint function following trauma and its inter-relation with degenerative changes requires an understanding of the normal state of structural loading in the joint. Very few studies have attempted to reproduce joint specific in vivo motions in vitro to quantify the actual loads carried by different tissues within the knee joint. The most significant challenge in this area is the very high sensitivity of the loads in joint structures to motion reproduction accuracy. A novel testing platform for assessing knee joint mechanics is described, comprised of a highly accurate (0.3 ± 0.1 mm, 0.3 ± 0.1°) six-degree-of-freedom (6-DOF) instrumented spatial linkage (ISL) for in vivo joint kinematic assessments and a unique 6-DOF parallel robotic manipulator. A position feedback system (ISL and position controller) is used for accurate reproduction of in vivo joint motions and estimation of "in situ" joint/tissue loads. The parallel robotic manipulator provides excellent stiffness and repeatability in reproducing physiological motions in 6-DOF, compared to the commonly used serial robots. The position feedback system provides real-time feedback data to the robot to reproduce in vivo motions and significantly enhances motion reproduction accuracy by adjusting for robot end-effector movements. Using this combined robot-ISL system, in vivo motions can be reproduced in vitro with very high accuracy (0.1 mm, 0.1°). Our results indicate that this level of accuracy is essential for meaningful estimation of tissue loads during gait. Using this novel testing platform, we have determined the normal load-carrying characteristics of different tissues within the ovine knee joint. The application of this testing system will continue to increase our understanding of normal and pathological joint states.
评估创伤后的关节功能及其与退行性变化的相互关系，需要了解关节结构负荷的正常状态。很少有研究试图在体外重现特定关节的体内运动，以量化膝关节内不同组织所承受的实际负荷。该领域最重大的挑战在于关节结构中的负荷对运动再现精度非常敏感。本文描述了一种用于评估膝关节力学的新型测试平台，它由一个用于体内关节运动学评估的高精度（0.3±0.1毫米，0.3±0.1°）六自由度（6-DOF）仪器化空间连杆机构（ISL）和一个独特的6-DOF并联机器人操纵器组成。位置反馈系统（ISL和位置控制器）用于精确再现体内关节运动并估计“原位”关节/组织负荷。与常用的串联机器人相比，并联机器人操纵器在再现6-DOF生理运动时具有出色的刚度和重复性。位置反馈系统向机器人提供实时反馈数据，以再现体内运动，并通过调整机器人末端执行器的运动显著提高运动再现精度。使用这种机器人-ISL组合系统，可以在体外以非常高的精度（0.1毫米，0.1°）再现体内运动。我们的结果表明，这种精度水平对于在步态期间有意义地估计组织负荷至关重要。使用这个新型测试平台，我们已经确定了绵羊膝关节内不同组织的正常负荷承载特性。该测试系统的应用将不断增进我们对正常和病理关节状态的理解。
