System for three-dimensional biomechanical analysis of joints

Abstract

We developed 3D MR based image processing methods for biomechanical analysis of joints. These methods provide quantitative data on the morphological distribution of the joint cartilage as well as biomechanical analysis of relative translation and rotation of joints. After image data acquisition in an open MR system, the segmentation of the different joint structures was performed by a semi automatic technique based on a gray value oriented region growing algorithm. After segmentation 3D reconstructions of cartilage and bone surfaces were performed. Principal axis decomposition is used to calculate a reproducible tibia plateau based coordinate system that allows the determination of relative rotation and translation of the condyles and menisci in relation to the tibia plateau. The analysis of the femoral movement is based on a reproducible, semi automatic calculated epicondylar axis. The analysis showed a posterior translation of the meniscus and even more of the femur condyles in healthy knees and in knees with an insufficiency of the anterior cruciate ligament (ACL).