In the knee, the menisci act as shock absorbers between the femur and the tibia. They prevent the bones from wearing out with every movement. That is why, when they crack, they must be taken care of.

The femur is placed on the tibia. But the two protuberances of its lower end are not directly in contact with the articular surface of the tibia. They are based on two menisci: the medial meniscus (on the inner side of the knee) and the lateral meniscus (on the outer side). These play the role:

• shock absorbers: their fibro-cartilaginous tissue is slightly elastic, which allows them to act as a buffer between the femur and the tibia, therefore to avoid the premature wear of these bones when strong mechanical stresses weigh on them;
• stabilizers: because they are thicker on their outer edges than on their central edges, the menisci form “wedges” around the femur. They thus help to keep it firmly in place on the tibia;
• lubricators: by their smooth and flexible material, the menisci facilitate sliding between the femur and the tibia, preventing the latter from rubbing against each other and wearing out.
  

Meniscus fissure in a young person, who is not yet prone to osteoarthritis, most often results from trauma. A sprained knee during a skiing accident, for example. But it can also occur more sneakily, by dint of always repeating the same sudden movement (repeated squats, etc.).

The tear may be inconspicuous or allow a piece to come off. We can then have a “tongue” of the meniscus that protrudes, or a fragment in a “jump handle”, only holding two ends.

In all cases, the injury is revealed by:

• severe pain in the knee, like stabbing. Particularly acute on the side or behind the joint, it can extend into the thigh;
• swelling of the joint, with episodic edema;
• crunches and a feeling of hooking the knee, which makes walking, climbing stairs and squatting very difficult;
• blockage of the joint, sometimes, if the detached meniscus fragment gets stuck between the bones.

Faced with such symptoms, it is absolutely necessary to stop the physical activity in progress, so as not to aggravate the lesion. You have to put your knee at rest, avoiding any support on the painful leg, and make an appointment with your doctor. While waiting for the consultation, pain and inflammation can be relieved by cooling the knee with an ice pack (wrapped in a cloth). It is also possible to take pain medication, such as paracetamol, or low dose nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen or aspirin.

Meniscus injury does not necessarily mean surgery. The treatment differs depending on the type of crack, its location, its extent, the patient’s age, sports practice, the general condition of the bones and cartilage, as well as any associated lesions (rupture of the anterior cruciate ligament, osteoarthritis, etc.).

Medical treatment, without surgery

If the patient is elderly or not very active, it is not always interesting to operate, at least not immediately. Rehabilitation sessions can be offered to strengthen the role of muscles in stabilizing the joint. A medical treatment based on analgesics or anti-inflammatory drugs, supplemented if necessary by a infiltration corticosteroids, can also relieve pain, at least temporarily. This makes it possible to delay or even avoid the intervention.

Meniscal repair, by suture

On the other hand, if the person is young and very active, the pain may increase and become unbearable on a daily basis. Surgery is welcome.

Surgeons try to preserve the meniscus as much as possible. This is why they favor its repair when they can, that is to say when the following conditions are met:

• the joint must be stable, with an intact or reconstructed anterior cruciate ligament (ACL);
• the fissure must be located on the periphery of the lateral (external) meniscus, because the area to be treated must be both accessible and sufficiently vascularized to allow good healing; 
• the rest of the meniscus must be healthy, without arthritis;
• the crack must be less than 6 weeks old to be able to repair itself;

The intervention is performed on an outpatient basis or as part of a short-term hospitalization (2 or 3 days). It is performed arthroscopically, that is to say using a mini-camera and mini-instruments introduced through two small incisions in the knee. It consists of suturing the crack using threads and small absorbable anchors.

Partial meniscectomy

If the meniscus cannot be repaired but the pain is still very present, meniscectomy may be considered. Provided that there is no functional instability.

Here again, the operation is performed on an outpatient basis or as part of a short-term hospitalization, under arthroscopy. This involves removing the damaged part of the meniscus, so that its roughness no longer grates on the femur with each movement.

After the operation, whether there has been a suture or meniscectomy, it is important to follow the surgeon’s instructions regarding downtime, rehabilitation and resumption of activities. Even if it may seem long, this program avoids complications: weakening of the sutures, stiffness afterwards, loss of muscle strength, etc.

The diagnosis is based on a clinical examination of the knee and imaging tests (x-rays and MRI). It is performed by the attending physician, an emergency physician, a rheumatologist or an orthopedic surgeon.