Meniscus Tear

What is the meniscus? General information

Three bones meet at the knee: the tibia, the femur and the patella. The meniscus sits between the femur and the tibia and is made of fibrocartilage, which protects the articular cartilage and helps stabilise the knee and lubricate it properly. In short, the meniscus is a cartilage whose role is to cushion, stabilise and protect the knee.

Each knee has two menisci: the lateral meniscus and the medial meniscus. The lateral meniscus is shaped like the letter "O", while the medial meniscus is shaped like the letter "C"; both attach to the tibia through their anterior and posterior horns. The medial meniscus is less flexible than the lateral one, which is why tears of the medial meniscus are far more common.

What causes a meniscus tear, and the associated types of injury

Meniscus tears can occur from the following causes:

• forceful twisting of the knee
• sudden stopping or twisting of the knee
• a rotational movement with the foot planted on the ground and the knee partially flexed (when lifting weights, or in tennis players)
• awkward pivoting of the knee when standing up abruptly from a chair or from a squatting position
• advancing age, as the meniscus wears down and can be injured more easily
• other knee injuries, such as a ligament tear, which can occur at the same time as a meniscus tear

When the meniscus is injured, the knee becomes much more sensitive to pressure. Meniscal injuries fall into two types:

• non-traumatic injuries – with advancing age the meniscus wears down and becomes thinner and more fragile. This can lead to degenerative meniscus tears, caused by something as simple as pivoting the knee incorrectly while getting up from a chair. Meniscus tears are not common in children
• traumatic injuries – these can occur in people who play a lot of sport (football, tennis, skiing, rugby) and in cases of direct contact (tackling). Here the knee is overloaded, and injuries can result from standing up abruptly out of a squat.

What are the symptoms of a meniscus tear?

The most common symptoms of a meniscus tear are:

• pain in the knee
• inflammation and swelling of the knee
• stiffness and locking of the knee
• difficulty bending and straightening the leg
• a feeling that the knee is unstable

When a meniscus tear happens, people may feel a pop in the knee but can often carry on with their activity as normal. At first the pain may not be troublesome, but after two or three days the knee starts to swell.

If it is not treated properly, a fragment of the meniscus can detach and move within the joint. The knee then locks, gives way, or makes noises while walking. The pain intensifies and walking becomes difficult.

How a meniscus tear is diagnosed

Patients who have suffered a meniscus tear should see an orthopaedic surgeon. A meniscus tear is diagnosed using the following methods:

• clinical examination – palpating the knee and testing the knee pain the patient reports. A few knee movements are then performed to pinpoint the affected area; the most commonly used are the McMurray and Apley tests. The orthopaedic surgeon bends the patient's knee, rotates it and brings it back into extension so as to put pressure on the meniscus. If this movement produces pain and the knee clicks when the test is repeated, a meniscus tear is present.
• imaging tests – following the clinical examination, knee X-rays and an MRI scan may be performed to confirm the diagnosis of a meniscus tear. X-rays can establish whether there are other causes of knee pain, while MRI gives a clearer picture of the soft tissues and of the knee joint.

Types of treatment for a meniscus tear

Treatment for a meniscus tear is prescribed by the orthopaedic surgeon and depends on the type, size and location of the tear. Other factors taken into account are the patient's age and the type of activity they do.

The outer third of the meniscus has a rich blood supply and is known as the "red zone". This area can heal on its own, although surgery is sometimes necessary.

Non-surgical (conservative) treatment

If the meniscus tear is small and the symptoms do not persist, conservative treatment alone is sufficient, without surgery. This treatment is known as the RICE protocol (Rest, Ice, Compression, Elevation) and consists of:

• rest – a break from the activity that caused the meniscal injury. The doctor may recommend using a crutch to avoid putting pressure on the affected knee
• ice – applying an ice pack for 20 minutes, several times a day. Ice should not be applied directly to the skin
• compression – applying an elastic bandage around the knee to prevent further swelling
• elevation – while the patient lies on their back during rest, the knee should be raised above heart level to reduce swelling

There are also non-steroidal anti-inflammatory medicines that can reduce pain and inflammation in the knee. These should be taken on the orthopaedic surgeon's recommendation.

Surgical treatment

If the meniscal injury is severe and the symptoms do not resolve after conservative treatment, surgery is required to heal the meniscus tear.

This is one of the most common arthroscopic procedures. It involves making an incision of about 1 cm and inserting a miniature camera. With this camera the orthopaedic surgeon can see clearly inside the knee while, through another incision, inserting the arthroscopic instruments used to repair or excise the torn portion of the meniscus.

Meniscal repair (suture)

Given how important the meniscus is to the function of the knee, it should be saved by suturing it whenever possible. The earlier the stage at which the meniscus tear is treated, the greater the chances of healing through repair.

Studies show that the risk of the meniscus failing to heal after repair is up to 20%. Even so, the long-term benefit of preserving the meniscus makes meniscal repair the best choice when dealing with a meniscus tear, particularly in children and adolescents.

Meniscectomy

This may be partial (removing the torn portion of the meniscus), subtotal or total (removing the entire meniscus). If one of the cruciate ligaments is also affected, the ligament must be treated as well, in order to prevent the possible onset of osteoarthritis.

Artificial meniscus implant and meniscus transplant

If a portion of the meniscus is removed and cartilage damage develops, the missing portion can be replaced with an artificial meniscus implant. The ACTIFIT artificial meniscus implant is recommended when the patient has an intact meniscal rim, with the anterior and posterior horns present.

What recovery after a meniscus tear involves

After meniscus surgery, the orthopaedic surgeon or a physiotherapist may recommend a set of rehabilitation exercises. The exercises should be performed regularly to restore mobility to the knee and, subsequently, to build muscle strength.

Depending on the orthopaedic surgeon's recommendations, the exercises can be done at home or at a specialist rehabilitation centre. The recovery and healing period varies according to the type of injury and the type of surgery.

Return to sport after these procedures depends on the type of surgery performed (meniscectomy or meniscal repair) and on the time patients devote to rehabilitation. There is a set of tests patients must pass in order to return to sport safely.