Removal of the posterior horn of the medial meniscus has an effect on the function of the knee joint. Removal of the posterior horn of the medial meniscus can cause traumatic arthritis, osteoarthritis and other diseases. 1. Traumatic arthritis: meniscus injury can lead to cartilage fracture, exfoliation and damage of the knee joint, causing traumatic arthritis. 2. Osteoarthritis: After meniscectomy, there will be gaps and defects between the femur and tibia, and the friction between the cartilage can lead to early damage to the cartilage and degeneration of the joints, causing osteoarthritis, which can cause joint pain and affect the flexion and extension of the knee joint and weight bearing. When the free body appears inside the knee joint, it can be stuck inside the knee joint when doing flexion and extension movements, and it can also cause limp leg or knee joint strangulation. Meniscus injury should actively go to the hospital, under the guidance of the doctor for standardized treatment, the specific surgery should be based on the degree of injury and personal circumstances, a comprehensive judgment to determine the development of the best surgical program.