A meniscal injury of the knee is a rupture of the semilunar fibrocartilage within the knee joint. The meniscus is located between the femoral condyle and the tibial plateau, one on the medial and one on the lateral side. In daily life, when the knee joint performs extension, flexion and rotation activities, the meniscus also appears to move accordingly. In terms of appearance, it serves as a wedge-shaped filling to accommodate the spherical surface of the femoral condyle; in terms of function, it plays an important role in conducting load, maintaining stability, and distributing synovial fluid. Once the meniscus ruptures due to long-term wear and tear or acute injury, it partially or completely loses its original function and even forms interference within the joint, affecting the normal movement of the knee joint, which can lead to osteoarthritis over time. When the knee is sprained for various reasons, the meniscus itself will tear when the tension on the fibrocartilage or the fibrous tissue around its periphery exceeds its own endurance. After an injury, the pain often occurs in a particular position and disappears when the position is changed. In some patients, the torn meniscus may form a block, resulting in temporary interlocking of the joint and immobility. There will be blood accumulation in the joint cavity and pressure points in the medial or lateral joint space plane, the latter being an important basis for meniscal injury. If the diagnosis is clear, meniscal injuries often require arthroscopic surgery, which is a minimally invasive treatment that requires only two incisions a few millimeters long and does not require sutures or stitch removal, and does not affect the aesthetics. Because of the important physiological function of the meniscus, arthroscopic surgery is performed to preserve and suture the healing meniscus as much as possible, rather than completely removing it; of course, for free, poorly supplied blood, the injury site cannot heal even with suturing and is usually partially removed.