A Dynamic Method of Measuring the Length of the Patellar Tendon Using Cine Magnetic Resonance Imaging

抄録

The purpose of this study was to propose a method of measuring the dynamic characteristics of the quadriceps muscle-loaded patellar tendon using cine magnetic resonance imaging (MRI). Five knees were imaged with 3D T1-weighted scans at rest and multi-slice 2D cine T1-weighted scans during knee flexion and extension. 2D cine images were acquired for 2 minutes, about every 1 second during active knee motion. Image registration based on 2D cine images was done with 3D reconstruction images using the transformation matrix from 3D images for the femur, tibia, and patella. The inverse matrix was defined as a transformation matrix that represented the motions of each bone. It was confirmed that the patellar tendon was in tension in 2D cine images, and the length of the patellar tendon was defined as the direct distance between each insertion site using 3D images. The length of the patellar tendon increased with knee extension, although previous studies during standing and prone positions had a tendency to stretch along with knee flexion. This difference in the length pattern of the patellar tendon was caused by the tensional force of the quadriceps muscle.