Accuracy Of 6dof Kinematics Of Tibiofemoral Joint Using High-speed Dfis Combined With 3d Mri Model

Abstract

Cui Zhang1,2,3,Yu Liu2* and Shaobai Wang21Biomechanics Laboratory, College of Sports and Health, Shandong Sport University, Jinan, China. 2School of Kinesiology, Shanghai University of Sport, Shanghai, China. 3Sports Biomehanics Laboratory, Shandong Institute of Sport Science, Jinan, China.*Yu Liu, (Corresponding author) PURPOSE: To validate the precision, accuracy and consistency of 6DOF movement of Tibiofemoral Joint via a custom high-speed Dual plane Fluoroscopic Imaging System(DFIS) combined with 3D MRI model registration. METHODS: 5 copper beads were embed in tibial and femur of one fresh pig hind leg separately. 3D beads rigid model and 3D skeleton model were reconstructed based on CT and MRI images of the beads and the tibia and femur of the pig hind leg separately. Flexion and extension movement of pig leg were recorded by high-speed DFIS. The registration results of 3D beads rigid model was set as gold standard. Bias, SD of bias, Bland-Altman analysis and Pearson correlation analysis were used to test the precision, accuracy and consistency of 6DOF results of MRI bone model, compare with gold standard. RESULTS: The 6DOF kinematic results of tibiofemoral joint obtained by high speed DFIS combined with MRI 3D bone model registration method was highly correlated to the results obtained by gold standard (r > 0.917). The bias and SD of bias of the anterior-posterior, medial-lateral, superior-inferior transitions, and flexion-extension, varus-valgus, internal-external rotations of tibiofemoral joint were in sub-millimeter and sub-degree level. The mean D-value of 3D MRI bone model registration and gold standard results were uniformly distributed within the consistency interval. CONCLUSION: Combined high-speed DFIS with MRI images to reconstruct 3D skeleton model for registration is a method with high accuracy, precision and consistency, which can be used to measure clinical 6DOF movement and soft tissue contact characteristics of the tibiofemoral joint. Funding was provided by the National Nature Science Foundation of China 81702211; the Movement Science Research Innovation Team(2019-183).