Rotational activities are the main cause of meniscus rupture. Meniscus injury is a kind of sports injury often seen in sports, often due to the uncoordinated joint activities, such as when kicking a soccer ball in the air, against the foot, or tripping during running and other states, the knee is in a semi-flexed position, when gravity passes through the joint, grinding and splitting forces occur, the meniscus is stuck between the femoral condyle and the tibial plateau, and the sudden extension and rotation causes injury, resulting in a tear. Medial meniscal injuries are caused when the knee is in semi-flexion and external booth, the meniscus is displaced toward the center and posterior side of the knee, and the lower end of the femur is injured between the weight-bearing surfaces due to sudden internal rotation of the femoral condyle and the tibial plateau by pulling the meniscus in between the femoral condyle and the tibial plateau due to external forces. Rupture of the lateral meniscus is mainly seen in the semi-flexed and inversion position of the knee, caused by abrupt external rotation and extension of the lower femur. If other conditions exist at the same time, such as long-term squatting labor, original had ligament injury, original had disc meniscus, etc., it is more likely to cause tears, the elderly due to degenerative aging of the meniscus, also easy to cause tears, and these tears can be caused even without obvious trauma. The site of meniscus injury. It can occur in the anterior horn, posterior horn, middle or marginal part of the meniscus. The shape of the injury can be transverse, longitudinal, horizontal or irregular, or even broken into intra-articular free bodies. In severe trauma cases, the meniscus, cruciate ligament and collateral ligament can be injured simultaneously. The most common symptom following a meniscus tear is pain during walking or exercise. The pain can be on one side of the joint, or posteriorly, or it can occur when the joint is moved into a certain position of extension and flexion. Many patients may experience a popping sound in the joint when squatting up and down or walking, often at a relatively constant angle. Sometimes there is also a sudden jamming of the joint that prevents movement or sudden weakness of the joint, which affects the quality of life. More seriously, the torn meniscus will also pull the synovial tissue during joint activities, wear out the joint tissue, cause chronic synovitis that is extremely difficult to cure, and accelerate joint degeneration, making arthritis appear earlier. Therefore, early diagnosis and treatment of meniscus tears is necessary.