The menisci are cartilaginous structures of the knee joint. They are located between the articulating bones, i.e. between the thigh bone (femur) and the lower leg bone (tibia). The menisci serve to establish better contact between the two bones and compensate for the incongruity due to their different shape and curvature.
In addition, they increase the force-absorbing surface in the knee joint and thus ensure a better distribution of joint pressure. In summary, the task of the menisci is to ensure stability and guidance of the knee joint and to transmit and distribute pressure. It should be mentioned at the beginning that there is an inner and an outer meniscus.
Both are anchored on the tibial plateau in a specific region, the so-called “area intercondylaris anterior and posterior” (bone surface between the condyles) on the bone. The inner meniscus is also connected to the outer ligament (collateral ligament) of the knee joint, making it much less mobile than the outer meniscus. Both have a crescent-shaped form (the outer meniscus even represents an almost closed ring) and can be divided into 3 areas each (anterior, middle and posterior area).
Meniscus lesion
The type and nature of meniscal lesions can vary in their severity and causes. The meniscus tear is considered the most common injury. This is understood to be an interruption of the continuity of the cartilaginous structure.
The causes are usually traumatic events or degenerative processes. Characteristic for degenerative injuries is the increasing pain, especially under stress. Strong shear forces, twisting or dislocation of the knee, falls and an abrupt stop of movement can lead to a torn meniscus.
Particularly in old age, but possibly also in younger age, signs of wear and tear and overstrain make a meniscus tear more likely. In principle, however, a meniscus can tear for injury and degenerative reasons. In both cases, the inner meniscus is more frequently affected than the outer meniscus.
The reason for this is the anatomical fact that the inner meniscus is less mobile, because it grows together with both the medial collateral ligament and the joint capsule. Therefore, in case of a meniscus lesion, one must always keep in mind that other structures are injured, such as the collateral ligaments or the cruciate ligaments. These ligament lesions can also be risk factors for meniscus injury: if the damage to the ligaments is not treated properly and there is still instability in the knee joint, it is much more likely that the menisci can be damaged as a result.
Torn menisci usually result in a rupture in the posterior third. In addition to the localization of a meniscus tear, different types of tears can be classified (transverse, longitudinal and handle-basket-like meniscus tear). In addition to the meniscus rupture, the cartilage discs may also detach from their bone surface.
