In the distal femur and proximal tibia, and the lower surface of the patella is covered with a layer of smooth tissue called articular cartilage, so that they can move freely and smoothly, and there are two cartilage pads (menisci) between the femoral condyle and the tibial plateau, namely the lateral meniscus and the medial meniscus, which are like “buffers” that protect the joint surfaces of both, absorbing downward-conducted shock, especially during excessive flexion and extension. They act as a “cushion”, protecting both joint surfaces and absorbing downward transmitted shock, especially during hyperflexion and extension. When jumping from a height, the knee is subjected to considerable force from the body’s gravity, but the cartilage of the femur and fetal plateau is not damaged because of the presence of the meniscus. Simply put, the meniscus has three important functions: 1. stabilize the knee joint. 2.Transmitting load to the knee joint. 3. Promote intra-articular nutrition. It is the meniscus that plays the role of load stabilization, which ensures that the knee joint does not get damaged after years of weight-bearing exercise. However, due to long-term wear and extrusion, degenerative changes in the elderly, this cumulative damage exceeds the capacity of the meniscus, resulting in meniscal injury. The clinical manifestations are: localized pain in the knee joint, pressure pain and swelling are obvious, inability to fully straighten the knee joint, ringing sound in the knee joint when moving, knee joint playing soft leg, pain is aggravated when going up and down stairs, the patient feels tearing and crunching sound in the joint, when checking the body, make the patient straighten 130. a 140. when it can be accompanied by interlocking symptoms of joint injury, positive McDonald’s sign. Imaging tests: can help to confirm the diagnosis. In particular, CTMRl has a high diagnostic rate. Meniscal injury is extremely difficult to heal because the blood supply is extremely poor, mostly avascular, and only 25-30% of the lateral side near the joint capsule has blood supply, so it is difficult to repair. At present, conservative treatment is generally used first. Manipulation therapy is performed by rotating the calf internally and externally to straighten the calf after flexion, which can relieve the symptoms of knee interlocking, or immobilization therapy by braking, fluid extraction, bandaging with elastic bandages, etc. Arthroscopic surgery is feasible for those whose conservative treatment is ineffective. Microscopic trimming, partial resection and suturing are beneficial to the knee joint and avoid premature hyperplastic degeneration of the knee joint due to total removal of the meniscus injury. Therefore, the introduction of arthroscopic technology is a great boon to patients with meniscal injuries.