In-situ Forces in Human Knee Ligaments During an Instability Test (Measurement using Robotics)

Abstract

In-situ forces in knee ligaments during anterior and posterior drawer tests were determined under the priciple of superposition. Sequential section of ligaments of two amputated knees was performed, while the three-dimensional path of intact knee motion was reproduced using a robotic system. Under 100 N of anterior force, the in-situ force in the anterior cruciate ligament (ACL) was 88 N at 0° of flexion and decreased to 54 N at 90° of flexion; however the in-situ force in the medial collateral ligament increased with increasing flexion angle. The posterior quarter of the anter-omedial portion of the ACL and posterolateral portion of the ACL were loaded under anterior force. Under 100 N of posterior force, the in-situ force in the posterior cruciate ligament (PCD was 30 N at 0° of flexion, and increased to 105 N at 90° of flexion. The anterolateral portion of the PCL was loaded under posterior force. All data were important for a better understanding of the mechanism of the knee instability test and for improvement of the diagnosis of the ligament injury. © 1995, The Japan Society of Mechanical Engineers. All rights reserved.