Meniscus

Cartilage disc, anterior horn, pars intermedia, posterior horn, inner meniscus, outer meniscus.

Definition

The meniscus is a cartilaginous structure in the knee joint that helps to transfer force from the thigh bone (femur) to the lower leg bone (tibia-tibia). The meniscus adjusts the round thigh bone (femoral condyle) to the straight lower leg (tibial plateau). Damage to the meniscus, such as torn menisci, leads to increased cartilage stress.

The result is premature wear and tear of the knee joint cartilage. As a result, knee joint arthrosis can develop. Therefore the meniscus plays an important role in our knee joint.

Anatomy

The meniscus is located in the knee joint. For each knee joint there is one inner and one outer meniscus. The meniscus is located on the side of the knee joint between the upper and lower leg. It consists of elastic fibrous cartilage, which can adapt to the movements of the knee joint. The meniscus is divided into 3 parts:

  • Meniscus anterior horn
  • Pars intremedia
  • Meniscus horn

The most common site of damage to the inner meniscus is the inner meniscus posterior horn.

Inner meniscus

The inner meniscus is, together with the outer meniscus, part of the knee joint. It is a c-shaped fibrous cartilage located between the two joint surfaces of the femur and tibia. The meniscus enlarges the joint surface and ensures even pressure distribution.

The menisci serve as “shock absorbers” and stabilize the joint. On the medial (inner) side, the inner meniscus is firmly fused with the joint capsule and the inner collateral ligament (inner ligament) and is therefore not very displaceable. Due to this anatomy, the inner meniscus is more frequently affected in sports injuries than the outer meniscus.

In normal movement, the inner meniscus is under tension during external rotation and is less stressed during internal rotation. Various sports such as tennis, handball, soccer or skiing can place a great deal of stress on the meniscus. But also with increasing age the meniscus loses thickness and wear and tear occurs.

So even normal movements or only a slight force may be sufficient to cause a tear in the meniscus and cause pain. Especially an injury of the inner meniscus can also occur in combination with a rupture of the cruciate ligament and a rupture of the inner ligament together, this combination of injuries is also called “Unhappy Triad”. Depending on the occurrence of the meniscus injury, the symptoms are different.

If it is a traumatic injury, such as can occur during a twisting and falling movement, the affected person suddenly feels pain in the joint space when walking or during twisting movements. In the case of an injury, part of the meniscus can also become trapped and the affected person has limited ability to stretch and bend the knee joint. If the injury is a sign of wear and tear that is degenerative, smpytomas are more common.

The affected person experiences increasing stress pain in the knee joint and possibly additional instability. The diagnosis is based on the patient’s medical history as well as different meniscus signs. Checking the pain during internal and external rotation, palpation (palpation) of the knee joint and the mobility of the knee joint can help in the diagnosis.

In addition, MRIs of the knee and X-rays are ordered to assess the bony structures as well. Therapeutically, attempts are made to suture meniscal tears, especially in young patients, and to preserve the cartilage. Depending on the prognosis, certain sports activities should be avoided in cases of severe injury. This should be discussed in detail with the doctor. In addition, there is a risk of earlier arthrosis in the knee joint as opposed to uninjured knees.