抄録
The objective of this study is to measure the change in shape and strain distribution over the entire surface of the Anterior Cruciate Ligament when its attachments are moved in three-dimensions, corresponding to knee flexion. An elaborate instrument (Knee Motion Simulator) was developed for measuring changes in shape and non-uniform distribution of strain in a Pseudo Ligament (crude rubber plate) when a three-dimensional displacement of the attachment was done.
Three-dimensional positions of 213 points, drawn in an uniform array at regular intervals on the pseudo ligament, were measured by the Stereo-photogrammetric method. Components of the Green-Lagrangian strain tensor were computed from squares made of four points each. Strain distribution on the ligament was arranged as a function of the knee angle, from 0° to 120° at intervals of 15°.
The experimental results demonstrated that; Strain distribution varied, even along the fiber direction, and large strain gradients were observed in the regions near the bone attachments.
On the anterior side, the region near the femoral bone attachment stretched noticeably at 60° of flexion, and almost the entire region along the fiber-direction stretched at 90° of flexion. The region near the tibial bone attachment stretched noticeably at 120° of flexion. On the posterior side, the strain in the region near the. femoral bone attachment was noticeable but not near the tibial bone attachment.
