1.Meniscal repair: It is suitable for those who have tears within 5mm of the attachment around the meniscus with the anterior and posterior angles intact, and most ideally for those with acute marginal meniscal tears combined with anterior cruciate ligament rupture. There are four types of repair: open, arthroscopic fully closed, arthroscopic from the outside in and arthroscopic from the inside out. The sutures are vertical decubitus, vertical layered, horizontal decubitus, knotted, etc. 2.Partial meniscectomy: It is applied to barrel stem rupture, longitudinal rupture or transverse rupture. Only the central part of the tear is removed, leaving a more stable surrounding meniscus sleeve or edge, which plays an obvious stabilizing role for the tibiofemoral joint. If the central part of the meniscus ruptures into the intercondylar fossa, the connection between the central part and the surrounding part in front is firstly severed transversely, then the front of the central part is clamped and pulled towards the intercondylar fossa, and the connection between the central part and the posterior corner of the meniscus is severed under direct vision. 3.Total meniscectomy: In view of the very important function of meniscus, try not to remove meniscus completely, because the result after complete removal is often satisfactory in early stage, and the satisfaction rate gradually decreases after several years due to degenerative joint disease, instability of knee joint and chronic bursitis. Complete meniscectomy is only indicated for those who have severe injuries to the parenchyma of the meniscus that cannot be healed, and whose fragmentation is severe enough to cause serious dysfunction of the knee joint. For total meniscectomy, there are various incisions that can be used, the commonly used anterolateral or anteromedial oblique incision, for narrow medial space, when it is difficult to remove the complete medial meniscus, a longitudinal incision should be added to the posterior edge of the medial collateral ligament, so that it is easier to separate the posterior horn of the meniscus. Care should be taken to protect the lateral meniscus from injury to the N tendon. After meniscectomy, the cartilaginous articular surface and cruciate ligament should be checked in turn to see if they are normal and if there is any free tissue debris, if there is, they should be repeatedly flushed and completely removed. Other special therapies 1, unlocking: when the patient has interlocking, it should be unlocked by early manipulation, that is, using mild external rotation plus rotation to move the knee joint, often can be unlocked, if the manipulation is ineffective, apply small weight of skin traction or stocking traction, when the muscle spasm is relieved, the pain decreases, slightly move the affected knee, most can be unlocked by themselves. 2. Braking rehabilitation: For meniscus edge tears, apply a long-leg cast or knee immobilizer to fix the knee in extension for 4-6 weeks. During the fixation period, the patient is asked to do more quadriceps exercises to help the patient recover and promote the absorption of joint effusion. 3, let the meniscus restore regeneration: this method is the most ideal method to treat meniscus injury. after the 80s, the use of pure natural sawtooth shark (i.e. big green shark) cartilage powder to achieve meniscus regeneration, from the inside to completely achieve the rehabilitation of the meniscus, has become a new attempt of advanced countries, has been vigorously promoted in Europe, America and Japan, and has been popularized to the clinical. 4, synovitis: damage to the synovial membrane by factors such as trauma or overexertion will produce a large amount of fluid, which will increase the pressure in the joint, and if not eliminated in time, it will easily cause joint adhesions and affect normal activities. Patients will feel knee pain, swelling, pressure pain, synovial membrane with friction astringent sound. 5, chondromalacia patella: mainly knee pain, the beginning is mainly pain when force, jumping pain, up and down stairs pain, squatting difficulties, often feel weak, playing soft, joint activities can have a loud, frictional feeling. Continued development may result in pain when walking on flat surfaces and joint swelling. There may be no abnormality in the radiograph, or there may be mild degeneration. 6. Knee ligament injury: The stability of the knee joint is relatively poor when it is slightly flexed, and if it is suddenly subjected to external forces that cause valgus or inversion at this time, it may cause medial or lateral collateral ligament injury. Patients will experience pain and pressure on the medial side of the knee joint, and the pain will increase when the lower leg is passively abducted. Knee movement will be limited.