The meniscus is an articular surface located on the medial and lateral side of the tibial plateau, which plays an important role in the human body, effectively protecting the cartilage and human joints to maintain normal knee motion. Meniscus injuries are mostly caused by torsional external forces, when a leg load-bearing, calf fixed in semi-flexion, external booth, the body and the femur violently rotated internally, the medial meniscus in the femoral condyle and tibial bone, by the rotational pressure, which led to meniscus tear. The greater the degree of knee flexion during sprain, the more backward the tear site, lateral meniscus injury mechanism is the same, but the direction of the force is opposite, rupture of the meniscus such as part of the slide into the joints between the joints, so that the mechanical obstacles to joint activity, preventing joint extension and flexion activities, the formation of “interlocking”. Meniscus injury can occur in the anterior horn, posterior horn, middle or edge of the meniscus. The shape of the injury can be transverse, longitudinal, horizontal or irregular, or even broken into intra-articular free body. Classifications include: marginal tears, transverse tears, longitudinal tears, horizontal tears, and anterior and posterior horn tears. In severe trauma cases, the meniscus, cruciate ligament and lateral collateral ligaments can be damaged at the same time. After meniscus injury, there is severe pain in the knee joint, inability to straighten automatically, and swelling of the joint. Pressure pain at the knee joint space is an important basis for meniscus injury. Meniscus injury should be treated in time, broken meniscus in the joint space to make the joint flexion and extension activities, and will cause damage to the articular cartilage surface, if the articular surface damage, the consequences will be irrecoverable, resulting in arthritis, if this time, then treatment, the effect will be much worse, so if the meniscus injury occurs, please consult a doctor in time.