The common clinical manifestations after meniscus injury include limited pain, joint swelling, popping and cross-locking, quadriceps atrophy, tenderness and definite tenderness in the knee joint space or meniscus area. 1, pressure pain The common sign is limited pressure pain along the medial and lateral knee joint space or around the meniscus. 2.McMurray test: The patient lies on his back, the examiner uses one hand to hold the medial edge of the joint, control the medial meniscus, the other hand holds the foot, make the knee joint fully flexed, the calf rotates externally and internally, and then slowly stretch the knee joint, and the popping or bouncing can be heard or felt; and then the hand is held against the lateral edge of the joint, the lateral meniscus is controlled, and the calf rotates internally and externally, and then the knee is slowly stretched out and popping or bouncing can be heard or felt, that is the positive test. If you hear or feel a popping or bouncing sound, the test is positive. McMurray test popping or sudden pain described by the patient during the examination, often has a certain significance for the localization of meniscus tear: popping between full flexion of the knee to 90 °, more suggestive of posterior meniscus tear; when the knee in the larger position of straightening popping suggests that the meniscus in the middle or anterior tear. 3, Apley grinding test, the patient prone position, flexion of the knee 90 °, the front of the thigh is fixed on the examination table, lifting the foot and calf, so that the joint separation and rotary action, the rotation of the force of tension in the ligament, if the ligament is torn, there is significant pain during the test. Thereafter, the knee joint in the same position, the foot and calf downward pressure and rotate the joint, slow flexion and extension, meniscus tear, the knee joint gap can have obvious popping and pain. 4, the classification of meniscus injury The classification of meniscus tear is of guiding significance for diagnosis and for the selection of reasonable surgical treatment methods and so on. There are many different classification methods for meniscus tear, the more common one is to classify it into edge type, center type, longitudinal rupture (i.e. “bucket handle type” rupture), anterior or posterior horn flap rupture and rare transverse rupture in the middle of meniscus. History of trauma, localized limited pain, joint swelling, popping and cross-locking, and atrophy of the medial head of the quadriceps. Localized compression pain, McMurray’s test (+), Apley’s grinding test (+). x-ray examination except other bone disorders, MRI examination, can clarify the diagnosis.