Biomechanical analysis of the effect of medial meniscus degenerative and traumatic lesions on the knee joint.

The purpose of this study was to determine the effect of the degenerative medial meniscus and traumatic lesions on the biomechanical behavior of the knee. An elaborate three-dimensional (3D) finite element model of the total knee joint containing bones, articular cartilages, main ligaments, and menisci was developed from a combination of magnetic resonance images and computed tomography. Three types of meniscus tears were employed to represent the degenerative and traumatic lesions. The stress and meniscus extrusion of healthy and injured knees were investigated under the posture of static stance. The traumatic longitudinal tear demonstrated the highest stress and the largest meniscus extrusion displacement. The degenerative horizontal and peripheral tears also showed an irregular biomechanical balance in the knee joint. Despite the damaged hemijoint, the stress on the healthy lateral hemijoint was increased. Although the biomechanics was deteriorated in all meniscus tear models, the variation degree was diverse. The transfixion damage could potentially cause future injury in the knee joint and accelerate the progress of osteoarthritis. Moreover, the meniscus injury may cause high-stress concentration on the contralateral side of the joint. The current results revealed the cause of different clinical manifestation after meniscus tears and the risk of knee osteoarthritis through biomechanical aspects.