Meniscal cartilage injury is caused by the sudden and violent twisting action of the knee joint, the femur and tibia crush the meniscus and cause injury. Meniscal cartilage injury of the knee joint is mostly seen when playing soccer, basketball or violent twisting of the joint. Clinical manifestations Most patients have an unknown history of injury; individual patients have a sudden tearing sensation in the knee joint at the time of rupture, with severe pain and inability to straighten voluntarily. 3 to 4 weeks later, the symptoms may gradually ease, while the affected knee still feels weak. The unique symptoms of meniscal injury are “interlocking” and popping, i.e., during flexion and extension, the knee suddenly feels as if something is stuck in the knee and cannot be moved. It is like the process of “locking” and “unlocking”. It is easy to diagnose with these typical symptoms, but not every patient has this condition. Some patients complain of knee pain and weakness, especially when walking on uneven surfaces or going up and down stairs. This should be examined in detail at the hospital to prevent misdiagnosis. Modern testing of the meniscal cartilage varies from anterior, posterior, and body angles to marginal and horizontal forms, and MRI of the knee is usually required. This is because the meniscal cartilage does not show up on plain X-rays. A knee arthroscope can also be inserted into the joint cavity to directly observe the meniscus for damage.