The common symptoms of third-degree meniscus injury are as follows: 1. There is obvious pain in the knee joint, and the pain is further intensified when the knee joint is flexed and extended. After meniscal injury, peripheral nerve damage occurs at the injury location, and the inflammatory lesion gradually forms, which will stimulate the surrounding tissues and lead to further strengthening of the pain, and the joint is prone to blood and fluid accumulation, which will stimulate the joint capsule and cause significant pain. 2. The knee joint is obviously swollen, because meniscal injury of third degree will lead to rupture of small blood vessels, and a large amount of blood leakage, and local After the formation of inflammatory symptoms, there will be inflammatory metabolic products exuded, resulting in a gradual increase in joint fluid, which will lead to significant swelling of the knee joint. 3, adverse knee movement, due to pain and swelling of the joint after the injury, it will lead to significant restrictions in the knee joint flexion and extension activities, after the cast or brace fixed for about a month, the symptoms are significantly reduced, swelling is significantly eliminated, after the removal of the cast and brace to walk This is mainly because the meniscus is not completely healed and the joint surface is not flat, so when walking or moving around, the meniscus is squeezed and there will be The pain and weakness of the leg are caused by the possibility of dislodgement after the injury, resulting in the sudden jamming of the free body in the joint, which causes significant pain and inflexibility of the joint, and requires shaking before the flexion and extension of the bent knee joint can be performed.