1. Joint swelling: Mostly seen in the acute injury stage. If the injury is prolonged, the joint swelling is not obvious. 2. Joint pain: Pain occurs when the knee is in a certain position, and disappears when the position is changed. 3. Joint interlocking and popping: Mostly occurs during walking. The ruptured and displaced meniscus is free in the joint space, preventing the normal activities of the knee joint, as if a lock is suddenly locked and cannot move, called joint “interlocking”, the sound it makes is “joint popping”; 4, muscle atrophy and weakness: the femur The quadriceps muscle is the main cause. The more severe the muscle atrophy, the more pronounced the weakness of the lower extremities; 5, a feeling of joint instability: when walking, there is often a feeling of knee instability, especially when walking on uneven roads or up and down stairs. Note: Clinical manifestations cannot be used independently as a basis for diagnosis, but must be analyzed in conjunction with medical history, comprehensive physical examination and imaging examinations to help make the diagnosis.