Cartilage tear (torn meniscus)

What is it?

The meniscus is an important structure within the knee joint commonly known as the cartilage. There are two cartilages within the knee, one on each side (medial and lateral). They are crescent shaped and made of tough fibrous cartilage slightly different to the joint surface (articular) cartilage lining the bone ends. Their job is to increase the area over which load is passed from the thighbone to shin bone, act as shock absorbers and lubricators and to a minor extent to stabilise the knee. A tear is a disruption through any part of the cartilage.

When does it occur?

The cartilages are vulnerable to injury due to the rolling, twisting and gliding movements of the knee joint.

In general tears can be caused in two main ways:

A significant single often sporting injury can cause a tear to a previously healthy cartilage, or more commonly a slightly worn cartilage is torn during normal routine daily activity. Although this may be a twist or a deep squat, often no specific event can be identified.

What are the symptoms?

The symptoms of a torn cartilage may include pain, swelling and catching. Occasionally with a large tear the knee will intermittently fail to fully straighten. Symptoms are often worsened by activity and the knee will tolerate impact activity less well. The symptoms may worsen over time as further damage occurs.

What is the treatment?

Some tears will settle with a period of rest and reduced activity. If there is no pain or swelling after a period of six to eight weeks then a short period of rehabilitation with the optional supervision of a physiotherapist will suffice.

Knee arthroscopy:
Symptomatic tears are treated with keyhole surgery (arthroscopy). As the cartilage has no blood supply, the majority of symptomatic tears are treated by removal of the torn fragment. Keyhole surgery allows accurate removal of only the damaged portion.

Meniscal repair:
Occasionally a very large tear or a detached cartilage can be treated by repair again with keyhole surgery.

Meniscal replacement:
For patients with an absent cartilage following previous extensive surgery it is possible to replace the cartilage with a synthetic implant or transplant a donor cartilage into the knee.