Effects of Bony Structure Simplification Methods on Biomechanics of Knee's Cartilage, Ligaments and Menisci in Series of Flexion Angles

To investigate the effects of bony structure simplification methods on the biomechanics of knee's cartilage and menisci under compression and torsion effects in series of flexion angles, the MRI images of the normal human knee at flexion angles of 0°/25°/60°/80° were developed through SONATA MAESTRO 1.5T, then through the technology of threshold segmentation and registration assembly, bone tissue distinguished models and single material models were built based on these images. The results show that: (1) Under three kinds of loads, the effects of bony structure simplification methods on the maximum equivalent stress of the cartilage in series of flexion angles were significant. At 0¡ãand 80¡ã, the maximum equivalent stresses of bone tissue distinguished models were much bigger than single material models. (2) The bearing load on cruciate ligaments of bone tissue distinguished models reduced. At 0°~60°, the maximum equivalent stress on ACL decreased with the more detailed bony structure. (3) The maximum equivalent stress of bone tissue distinguished models were chiefly bigger than single material models in series of flexion angles. The menisci of bone tissue distinguished models will bear more loads than single material models. (4) The stresses on soft tissue of two kinds of models all elevated with the increase of flexion angle, so bony structure simplification methods did not affect the stress trends with the change of flexion angle. But at 0° and 80°, the effects of bony structure simplification methods on biomechanics of knee's cartilage, ligaments and menisci were significant. The study provided techniques and data for definition of tibiofemoral joint material properties during the mechanical analysis of knee motion.