Grade 1 – 4 of the meniscus lesion

A meniscus lesion, i.e. a tear, crack or degenerative alteration of a meniscus can be caused on the one hand by an injury (trauma) and on the other hand by signs of wear. Depending on the severity of the lesion, the meniscus lesion is divided into 4 degrees of severity. Grades 1-3 are due to wear and tear, grade 4 and above is called a meniscus tear.

If there is a meniscus lesion of grade 1, the damage to the meniscus is centrally located, small and punctiform. The patient usually notices nothing or very little of this.
A meniscus lesion of the 2nd degree runs horizontally in the meniscus, but does not reach its margins.
The meniscus damage of the 3rd degree differs from the 2nd degree mainly by the length, respectively the size of the lesion.
In the 4th degree, the injury extends to the edge of the meniscus, so that a deep tear is created. These tears can be divided into different subclasses.
The most common are the radial tear and the basket handle tear. The radial crack “divides” the meniscus into two halves, in the case of a crack in the basket handle, the inner parts crack, so that a “handle-shaped” space is created that is closed off from the outside. Such patterns of injury can be easily recognized by diagnostic imaging procedures such as magnetic resonance imaging (MRI) in the case of a torn meniscus. Patients with a meniscus lesion of grade 4 usually show clear symptoms, such as pain and restricted movement.

Causes of a meniscus lesion

In principle everyone can suffer from a meniscus lesion, but on the one hand athletes and on the other hand older people are predisposed to it. Among the patients there are about twice as many men as women. The movement that causes most meniscus lesions is a combination of a rotational movement combined with a pressure load.

Such movement can occur in certain sports, such as soccer or skiing. Younger people are particularly affected by this form of meniscus injury.In older people, however, often no direct trigger of a meniscus tear is recognizable. This is due to the fact that the cartilage tissue of the menisci becomes heavily and partially overstressed over the course of time, resulting in the formation of ever more small tears.

These remain unnoticed for a long time, until at some point a slight strain causes the meniscus to tear permanently. This form of meniscus damage mainly affects people over the age of 40. The symptoms described by a patient with a meniscus tear differ depending on the severity and location of the meniscus lesion.

Frequently, when trauma has caused the tear, the first thing that is noticed is a crack or snap across the joint space. In addition, the affected person suddenly feels pain (depending on the torn meniscus either on the outside or inside of the knee), which increases when bending or stretching, i.e. especially when walking. The meniscus itself is not responsible for the pain, since the cartilage tissue is not supplied with nerves at all, but torn fragments can irritate the joint capsule.

In some cases, this results in a joint effusion, i.e. an accumulation of fluid in the knee joint, which can become noticeable as swelling. In some cases, a part of the meniscus slides into the joint space and thus “blocks” the knee joint. The consequence is that neither extension nor flexion is possible in the joint. Sometimes, an injury to the inner meniscus is associated with a rupture of the anterior cruciate ligament and the inner collateral ligament, which is then referred to as “unhappy triad”. In addition, this injury usually results in bleeding into the joint and the signs of cruciate and collateral ligament damage are positive.