The difference between meniscal injury and synovitis is obvious, in terms of etiology, pathological changes and symptoms. Meniscal injury is caused by degeneration of the meniscus due to chronic strain, or acute meniscal injury due to acute violence, resulting in swelling and pain in the knee joint, which can worsen during activity, especially when walking up hills or up and down stairs, and in severe cases can lead to interlocking and seizure of the knee joint, affecting the function of the knee joint. Synovitis is mainly caused by immune factors that lead to synovial hyperplasia, hypertrophy, vascularization, and increased inflammatory exudation of the synovial membrane resulting in effusion of the knee joint, resulting in redness, swelling, and pain in the knee joint. Patients with synovitis may experience soreness and swelling in the knee joint at rest, and the symptoms may worsen after activity. If the treatment of synovitis is not systematic and regular, the inflammation may cause damage to the entire knee joint over time. The late stage of meniscal injury and synovitis can cause deformation, hyperplasia, and cartilage wear in the knee joint, resulting in traumatic arthritis or osteoarthritis, which is relatively difficult to distinguish.