The third degree of meniscus injury is degree III, and its clinical manifestations are mainly pain, activity limitation, joint effusion, swelling and so on. 1. Pain: The most important manifestation of meniscus injury of the third degree is severe pain, and the pain is aggravated when walking, rotating or twisting the joints, and the pain will not stop when the joints are at rest. 2. Restriction of activities: Due to the large meniscus damage, patients may feel obvious pain when walking, so there are symptoms of walking, walking up and down the stairs and other activities are obviously restricted; in addition, there may also be joint interlocking performance, that is, the leg is suddenly fixed when walking, unable to straighten or flexion. 3. Joint effusion and swelling: because of the stimulation of the injury, the knee joint may also have intracavitary fluid accumulation, local muscle and fascia swelling, etc. If there is fluid accumulation, the patient’s main manifestation is the stiffness of the knee joint. Meniscus Ⅲ degree damage, it is recommended to go to the regular hospital in time, timely treatment, so as not to delay the condition.