Synonyms
meniscus tear, meniscus tear, meniscus rupture, meniscus damage
Definition
The term meniscus lesion (also: meniscus tear, meniscus rupture, meniscus injury) describes a damage of the inner or outer meniscus of the knee. The inner meniscus is affected by lesions far more frequently than the outer meniscus because it is attached to both the joint capsule and the inner ligament and is therefore less mobile. Most often, such lesions are caused by direct exposure to violence, for example during sports, or by signs of wear and tear (degeneration), usually due to age.
Excursus meniscus: The meniscus consists of two crescent-shaped fibrocartilage discs, which are positioned between the upper and lower leg in order to compensate for the incongruity (inequality) of the articulating bones, as mentioned above, and thus to transfer impacts evenly to the cartilage of the lower leg. In addition, the meniscus distributes the synovial fluid, which is particularly responsible for protecting the cartilage tissue, since it causes cartilage discs to slide over each other without friction. It also supplies the cartilage tissue with nutrients and is responsible for the removal of waste products from the joint space.
The diagram on the right shows the anatomical structure of both menisci. In the middle, the two menisci are separated by the cruciate ligaments. To the left of the cruciate ligament is the outer meniscus (light blue coloring), to the right of the cruciate ligaments is the inner meniscus (grayish coloring). and the posterior cruciate ligament. As you can easily see in the diagram, the volume of the outer meniscus is much larger than the volume of the inner meniscus.
Forms
There are different degrees of severity and different forms of meniscus lesions. If the meniscus is only bruised, this is called a contusion (see: Meniscus contusion). But if it is actually torn, one distinguishes between three types of tear: In the case of a radial or flap tear, the line runs from the inner edge of the meniscus to the outside, in the case of a horizontal tear, the tear runs horizontally, and in the case of a tear in the basket handle, the tear runs longitudinally through the meniscus. A torn basket handle carries the risk that a free edge slips into the joint space and thus leads to worse complaints. The posterior horn is particularly often affected by the tear, among other things because it has the worst blood supply.
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