Meniscus injury, first of all, is related to the important function of the meniscus in the knee joint. The meniscus is an important fibrous tissue cushion in the knee joint, which has the role of cushioning the femoral surface and tibial surface from frictional impact and avoiding damage to the cartilage during movement. Secondly, it is related to the following predisposing factors: 1. In young and middle-aged patients, during strenuous exercise, the knee joint is semi-flexed due to single-leg weight-bearing exercise, and if twisting occurs, it is easy to cause extrusion of the meniscus and acute sprain. 2. In middle-aged and old-aged patients, due to long-term chronic strain on the knee joint, the meniscus degenerates and becomes brittle, and during repeated knee flexion activities such as mountain climbing and stair climbing, it is easy to occur 3. Due to congenital developmental deformities, the disc-shaped meniscus is prone to wear and tear degeneration during knee flexion and extension and rotation activities, resulting in injury.