Meniscus tear

The healthy meniscus

The meniscus is a disc-shaped structure in between the upper leg (femur) and lower leg (tibia). The structure is made from a special type of cartilage called fibrocartilage.

Each knee has two menisci: one on the inner side (C shaped) and one on the outside (O shaped).

One of the most important functions of the meniscus is shock absorption. This protects the cartilage from premature wear and tear and prevents arthritis. A large percentage of our weight and the force generated by walking, running and jumping is absorbed by the menisci. The meniscus also ensures that the knee is stable. Its shape allows the upper leg (round shape) to fit better with the lower leg (flat shape). The meniscus also has a role in nourishing the cartilage that covers the joint surfaces.

An intact meniscus between the cartilage of the upper leg (femur) and lower leg (tibia)

The torn meniscus

A tear in the meniscus can be caused by a sudden and abrupt movement while doing activities like sports. This is called a 'traumatic tear'. A classic ‘crack’ is heard as the meniscus tears. The injury can happen when someone stands up from a crouching position. It is not necessary to put a lot of force on the knee to cause a tear.

In addition, a tear in one of the menisci can also develop over a slow and long-lasting process, without any acute incident. This is what is called a degenerative tear or tear due to ‘wear and tear'. As we age, not only does the quality of the cartilage (progress towards wear and tear or arthrosis) go down, so does the quality of the meniscus. This can lead to spontaneous tears, even without trauma. The meniscus can have a frayed appearance and can show a tear due to so-called ‘wear and tear'.

Torn meniscus between the upper leg and lower leg

Different types of meniscus tears

Symptoms and complaints

The following symptoms are the most common when there is a meniscus tear. They can be different for each individual patient and are not necessarily present.

• Pain: this happens mostly when bending and stretching the knee. The pain is initially severe but can decrease in intensity.
• Swelling: the result of an outpouring of fluid or bleeding in the knee.
• Giving out: the knee feels ‘weak’ and feels like it is going to 'give out'.
• Click: there is a palpable or audible click in the knee.
• Blockage: in very pronounced cases, there is a true blockage, and the knee can no longer bend or stretch.

The symptoms of a meniscus tear can be similar to those of other knee conditions.

Diagnosis

In addition to an in-depth discussion with the patient (medical history) and a thorough clinical examination, sometimes technical tests are performed to arrive at a definitive diagnosis.

• X-ray imaging: especially to rule out wear and tear, fractures or other knee injuries.
• NMR scan: a diagnostic procedure that uses a combination of magnetic waves and computer processing to create detailed images of the knee joint.
• CT scan (without contrast): performed in combination with radiation and computer processing to visualise cross-sections of the knee.
• Bone scan: very small quantities of radioactive-marked sugar molecules are injected intravenously. These then fasten to the places in the body where there is increased bone cell activity.

NMR imaging of the torn meniscus

Treatment

The meniscus has poor circulation. This means that only tears in the outer third have a chance of spontaneously healing. Tears in the middle third can heal if they are sutured. Tears in the inner third will never heal sufficiently and must often be removed.

The surgeon will decide on a specific treatment of the meniscus tear. The following will be considered:

• Your age, overall health condition and medical history
• The extensiveness and location of the injury
• Expectations for further progression of the injury

Possible treatments are:

Muscle strengthening exercises: for some people - especially for older people - the symptoms can be reduced progressively.

A knee injection of a low dose of cortisone, a cartilage-supportive gel or a blood patch (PRP or platelet rich plasma).

A surgery. Surgeries on the meniscus are usually performed using a keyhole surgery (arthroscopy). The type of treatment chosen depends on your age and the nature and severity of the meniscus tear.

Latest publication date: 22/06/2023
Supervising author: Dr. Desmyter Stefan