The meniscus is two fibrous cartilages shaped like a crescent moon, located in the gap between the femur and the tibia in the human body. Meniscus shape: from above, the lateral meniscus like “O”, the medial meniscus like “C”; from front to back, both meniscus like a triangle. Functions of meniscus: Conducting pressure; absorbing shock; stabilizing the knee joint; limiting excessive flexion and extension of the knee; lubricating the knee joint. Mobility of the meniscus: the lateral meniscus has a high degree of mobility and is relatively easy to injure; the medial meniscus is more fixed and is relatively less likely to be injured. Distribution of blood flow in meniscus: outer 1/3 is red zone, covered by blood flow, which needs to be preserved as much as possible during surgery middle 1/3 is red and white zone, part of blood flow exists, which can be removed if ruptured inner 1/3 is white zone, not covered by blood flow, which can be removed if ruptured. Meniscal rupture usually starts from the white zone, if not treated in time, the rupture can be extended to the red and white zones or even the red zone, if the rupture is extended to the red zone, it will be more difficult to deal with. Meniscus injury causes: 1, acute traumatic tear: mostly seen in young people’s sports injuries, when the knee joint fast twisting, vigorously kicking the ball kicking empty, squatting walking, running tripped easily produce meniscus injuries; 2, chronic degenerative tear: meniscus degenerative degeneration and age growth, repeated knee activities caused by the chronic injury related to the injury is commonly found in the posterior corner of the medial meniscus injury. Types of meniscus rupture: typical symptoms of meniscus injury: pain, knee interlocking (i.e., stuck feeling), flexion, extension range of motion is reduced, and there is a popping sound in the knee joint. Physical examination for meniscus injury: McKnight’s test, grind test, squat walk test. Examination of meniscus injury: magnetic resonance examination (non-invasive, commonly used in clinical practice); arthrography (invasive, less commonly used nowadays); arthroscopy (invasive, but treatment can be carried out at the same time as the examination); Treatment of meniscus injury: 90% of meniscus rupture needs to be treated by surgery. Meniscal injuries that show less than grade III on MRI can be treated conservatively for the time being. Conservative treatment: braking, reducing walking, standing and squatting, etc. Regular review is needed, and surgery is needed if the degree of rupture worsens. Surgery is recommended for meniscus injuries of degree III or above on MRI. Surgical treatment: 1, incision surgery: more traumatic, has been less used. 2, arthroscopic surgery: less traumatic, has been less used. 2, arthroscopic surgery: less traumatic, good efficacy, fast recovery, is currently the first choice of clinical treatment of meniscus injury. Surgery: partial resection, most of the meniscus, total resection, meniscus suture, meniscus transplantation. Consequences of meniscus injury: The biggest danger of meniscus injury is that when walking and exercising, it will lead to wear and tear of the cartilage of the knee joint and damage, resulting in permanent cartilage damage of the knee joint. When cartilage damage reaches a certain level, it is often difficult to achieve a satisfactory outcome, even if the meniscus injury is managed surgically! If symptoms, physical examination and MRI agree that a meniscus injury exists and requires surgical treatment, it is recommended that you seek treatment as soon as possible. The optimal time for treatment is usually within three months of definitive meniscus injury. Walking and moving around for a long period of time with a meniscus injury will cause irreversible wear and tear on the knee cartilage!