The meniscus is a pair of crescent-shaped cartilaginous discs that connect the thigh and lower leg. Injuries as well as joint wear can cause damage to the meniscus, such as a meniscal tear or a meniscal crush. Typical symptoms suggestive of acute meniscal injury are severe knee pain. If a meniscal tear occurs, it must always be treated to avoid long-term damage to the knee. An operation is not always necessary.
Meniscus: Cartilage disc in the knee
The two menisci in the knee play an important role in the transmission of force and pressure from the thigh to the tibia. They adjust the rounded thigh bone to the straight lower leg and thus increase the contact surface between the two bones.
Since the menisci have a great elasticity, they can also bounce shocks from the upper leg to the lower leg well - so they have a shock absorber-like function. In addition, the menisci are probably also important for the distribution of synovial fluid. Together with the ligaments they additionally contribute to the stabilization of the knee joint.
Degenerative changes in the knee
As with other cartilage surfaces, degenerative changes over time also occur on the meniscus over time. Since the meniscal tissue is not directly supplied with nutrients, but is only indirectly fed via the synovial fluid, the ability to regenerate the meniscus is limited.
In old age, the cartilaginous tissue becomes brittle due to the lack of regenerability and fine cracks may form. These cracks can then result in a meniscal tear even at low stress. The more the meniscus is stressed, the sooner such signs of wear can occur - sometimes they can be observed even in younger people who put heavy strain on their knees. About half of all meniscal lesions are triggered by degenerative changes.
Causes of a meniscal injury
Injuries to the meniscus primarily affect athletes as well as persons whose occupational activity puts a heavy strain on the knee. In sports, a meniscus injury can occur either during a quick turn or during rapid bending and stretching of the knee joint. Typical is the occurrence of a meniscus injury after a rotational fall motion. It can happen that the meniscus edge gets between the joint body and tears.
The sports that are particularly frequent include menial injuries such as football, handball and basketball, but also tennis, skiing, karate and cycling. Often in the sport of a meniscal injury, a meniscus disc is expected to wear out - in rare cases, however, trauma may also result in injury to a fully intact meniscus. Often, injuries to the meniscus occur along with other knee injuries, such as a cruciate ligament tear.
Meniscal tear: symptoms
Above all, meniscal tears that are caused by an accident and are not degeneratively caused are perceived as very painful. If the torn meniscus parts between the articular surfaces, this leads to severe pain in the knee. On the other hand, if the cause is a degenerative change on the meniscus, increasing pain in the knee joint, which primarily occurs under exercise, is a typical symptom.
In the case of meniscal damage, the affected knee joint usually can not be properly moved and loaded. It is particularly common to observe that the knee can no longer be fully stretched. If a piece of the meniscus is torn off, the affected patient has the feeling of having a foreign body in his knee. In addition, a crackling sound in the knee is often another symptom that indicates meniscal damage.
The injured meniscus can cause damage to the articular cartilage, as it is now more heavily loaded. The substances that are released in the degradation of the articular cartilage, an inflammation in the knee can be caused - a so-called joint effusion. This is characterized by a strong swelling and overheating of the knee.
Diagnosis of a meniscal tear
If pain suddenly occurs in the knee, you should immediately cool the injured knee to prevent excessive swelling of the joint. In addition, raise your leg and move it as little as possible. If there is any suspicion of meniscal damage, seek medical advice immediately.
The treatment of a meniscal tear is unavoidable because it can not heal by itself due to the lack of blood flow to the meniscus. The attending physician can make a first diagnosis through various manual tests. Subsequently, this is supported by an X-ray examination or a magnetic resonance tomography.
In meniscus damage one differentiates between a violation of the inner meniscus and the outer meniscus. Injuries of the inner meniscus occur much more frequently, because the inner meniscus fused firmly with the inner band and the joint capsule and therefore is not very flexible.
If a rupture develops in the meniscus, a distinction can be made between different types of rupture:
- Bucket-handle tear
- Complex crack
Magnetic resonance imaging can diagnose about 90 percent of all meniscal tears. Nevertheless, there are some cases where no clear diagnosis can be made in this way. In case of persistent symptoms then a knee arthroscopy is performed in which in the event of damage this can be corrected directly.