Functional assessment for the natural knee joints in squat activity by simulation of 2D X-ray images based on 3D CT images

Abstract

In biomechanics of the knee joints,the definition of the cruciate ligament adhesion areasis discussed for the cruciate ligament reconstruction. Effectiveinformation can be expected to be fed back to the cruciate ligament reconstruction if accurate movement of the natural knee jointscan be analyzed.Therefore, this study performed in vivo six-degree-of-freedom(6-DOF) motion analysis for the natural knee jointswith high precision using an image matching technique. Theimage matchingtechnique was performed determining the strength of correlation betweenthe X-ray images from asingle-planeflat panel detector (FPD) and the computationalsimulatedimagefrom three-dimensional gray-scale model reconstructed using computed tomography (CT). Average root mean square errors of this techniquewere 0.84 mm for the in-plane translation, 0.17 mm for the out-of-plane translation, and 0.29 degrees for the rotation.We report analysis resultsfor the natural knee joints insquat activityusing this technique.Subjects werethe natural knee joints offourhealthy men.Weassessed the four items for the motion pattern and the functionality of cruciate ligament.The roll-back motion of subluxation in high-flexion, and the importance of anteromedial(AM)bundle and posterolateral(PL)bundle in the anterior cruciate ligament(ACL)could be confirmed from the results.From these, this highly accurate techniquecanbeexpected to becomeavaluable tool for the medical device development and the diagnostic in field of orthopedics. © 2011 The Japan Society of Mechanical Engineers.