1. Meniscus: It is 2 crescent-shaped fibrocartilage located at the edge of the knee joint surface. Main functions: 1, improve joint stability. 2, joint lubrication and nutrition. 3, Limit knee hyperextension and hyperflexion (locking mechanism). 4, regulate intra-articular pressure. 2, the old and young differ: young and strong meniscus of the knee joint is more elastic, cushioning shock force, trauma caused more meniscal tears; the elderly meniscus is less elastic, trauma caused more wear and tear of the meniscus. 3, the source of pain: The meniscus of the knee joint has no sensory nerve endings, the pain symptoms come from the stimulation of the joint capsule of the meniscus tear; meniscus tear instability in the process of knee joint activities produce abnormal activities, pulling stimulation synovial membrane. 4, meniscus injury symptoms: typical performance for joint locking (joint in the process of activity suddenly stuck, can not extend and flex the situation, when there is usually a sudden pain, usually rest, their own light activity can resume activities, called “unlocking”) In addition, there are joint swelling and pain, popping, playing soft leg, restricted activity, unstable step The pain is more pronounced when walking down stairs. If the disease is prolonged, quadriceps atrophy may occur. 5, post-injury precautions: can not walk with pain – aggravate the meniscus tear; strenuous activity, repeated flexion and extension of the joint – cause cartilage damage; with joint locking, immediate hospital consultation, MRI. 6, the purpose of surgery: conservative treatment is ineffective, with obvious clinical symptoms of meniscal injury need surgery to restore the stability of the meniscus in the process of knee activities, remove pain-causing factors, to avoid damage to the meniscus on the The meniscus should be operated to restore the stability of the meniscus during knee movement, remove the pain-causing factors, avoid the wear and tear of the meniscus on the femoral condyles and tibial plateau cartilage, and restore the physiological function of the meniscus to the maximum. 7. Surgery: In recent years, arthroscopy has become the gold standard for surgical treatment of meniscal injuries. Meniscus surgery is less invasive and more effective. Specific methods: meniscectomy, meniscus suture, allograft meniscus transplantation. As long as the meniscus injury can be correctly diagnosed and actively treated, most patients are satisfied with the results and can work and live normally.