The meniscus is one of the important structures that make up the knee joint. From the shape and location of the meniscus, it lies between the femoral condyles and the tibial plateau, acting as a cushion to protect the joint surfaces of both, absorbing the downward shock. It is the stabilizing effect of the meniscus that keeps the knee joint from being damaged by years of weight-bearing exercise. The meniscus is so important to the knee joint, so what can damage it? 1, do a sharp turn sharp stop action This kind of situation is common in sports, such as playing basketball, soccer, sharp turn sharp stop to “shake” off the opponent, if the warm-up is not sufficient, the action is not standardized, it is easy to damage the meniscus. In daily life, such as lifting heavy objects, unstable standing when rushing off the bike, may also lead to this situation. 2.Impact For example: collision between the leg and the opponent when playing soccer, or a car accident where the leg hits the car, can also cause damage to the meniscus. 3, chronic injury Many people may not have suffered obvious trauma before, but the usual work, household chores are too heavy, especially the need to squat often, which will also cause the meniscus slowly appear symptoms of strain. Initial self-judgment 1, the joint appears “don’t stuck” feeling Many patients with meniscus injury, when walking or doing a certain action, will suddenly feel that the leg can not move, the joint inside like “stuck” like. If you move the joint slowly, this “stuck” feeling may disappear. This is medically known as the “crossover phenomenon” of the joint. This occurs when a torn meniscus becomes stuck in the joint, causing a restriction in joint movement. However, it is not always the case that the meniscus is damaged. If there are small free bones in the joint, they may also get stuck in the joint and cause the phenomenon of interlocking. 2, over-extension, overflexion with pain When there is a suspicion of meniscus injury, you can lie on the bed, try to let the knee joint in full extension, and then gently extend the lower leg upward, this action will lead to the front of the joint pressure becomes large, if there is damage to the meniscus, in doing this action, the squeezed and strained meniscus will produce pain; conversely, we will be the maximum degree of knee flexion, will let the back of the knee joint If this time produces pain, it means that the posterior horn of the meniscus may be ruptured. 3, squatting and walking pain This action is to check whether there is damage to the posterior horn of the meniscus, by squatting and walking, and changing direction from time to time, either left or right. If there is pain or ringing in the knee when doing these movements, or if the knee cannot be flexed at all, this indicates that there may be damage to the posterior horn of the meniscus. Tip: The above two examinations should be done in moderation to avoid aggravating the damage to the meniscus by repeated examinations. X-rays X-rays cannot directly diagnose meniscal injuries because cartilage does not appear well on X-rays. The reason why X-ray is performed on patients suspected of having meniscal injury is for the purpose of differential diagnosis. For example, to rule out intra-articular free bodies, bone tumors and other problems, in addition to the overall degeneration of the joint can also be an understanding of the situation. 2, CT CT is to scan the bone layer by layer, but its diagnosis of meniscal injury is relatively limited, and the accuracy rate is not high, currently in the diagnosis of meniscal injury has been replaced by MRI. 3, MRI MRI is by far the most accurate adjunct to non-invasive testing for the diagnosis of meniscal injuries, with an accuracy rate of 90%. According to the degree of abnormal signal changes within the meniscus in relation to pathological changes, MRI images of meniscal degeneration and tears of different degrees and morphological abnormalities can be classified into three levels of signals. Usually tertiary signal changes are seen pathologically as fibrocartilage fractures, so a meniscal tear can be diagnosed when tertiary signal is seen on a slice of the meniscus with morphologic irregularities. 4. Arthroscopy Arthroscopy can provide a definitive diagnosis for patients who have symptoms of meniscal injury and are suspected of having meniscal injury but cannot be detected by MRI, but because arthroscopy is an invasive test, it needs to be chosen with caution.