One of the most commonly injured parts of the knee, the meniscus, is a wedge-like rubbery cushion where the major bones of your leg connect. Meniscal cartilage curves like the letter ‘C’ at the inside and outside of each knee. A strong stabilising tissue, the meniscus helps the knee joint carry weight, glide and turn in many directions. It also keeps your femur (thighbone) and tibia (shinbone) from grinding against each other.
Football players and others involved in contact sports may tear the meniscus by twisting the knee, pivoting, cutting or decelerating. In athletes, meniscal tears often happen in combination with other injuries such as a torn ACL (anterior cruciate ligament). Older people can injure the meniscus without any trauma as the cartilage weakens and wears thin over time, increasing the likelihood of a degenerative tear occurring.
Signs and symptoms
You might experience a "popping" sensation when you tear the meniscus. Most people can still walk on the injured knee and many athletes keep playing. When symptoms of inflammation set in, your knee feels painful and tight. For several days you will have:
- Stiffness and swelling
- Tenderness in the joint line
- Collection of fluid (‘water on the knee’)
Without treatment, a fragment of the meniscus may loosen and drift into the joint, causing it to slip, pop or lock - the knee then gets stuck, often at a 45-degree angle, until it is manually moved or otherwise manipulated. If you think you have a meniscal tear, see your doctor right away for diagnosis and individualised treatment.
It is important that you describe to your doctor exactly what happened and when. He or she may conduct physical testing to evaluate the extent of your meniscal tear, although you may first need X-rays to rule out osteoarthritis or other possible causes of your knee pain. Sometimes your doctor may use an MRI (magnetic resonance imaging) scan to get a better look at the soft tissues of your knee joint. Your doctor may also use a miniature telescope (arthroscope) to see into your knee joint, especially if your knee locks.
Menisci tear in a number of different ways:
- Young athletes often get longitudinal or ‘bucket handle’ tears if the femur and tibia trap the meniscus when the knee turns.
- Less commonly, young athletes get a combination of injuries called radial or ‘parrot beak’ tears in which the meniscus splits in two directions due to repetitive stress activities such as running.
- In older people, cartilage degeneration that starts at the inner edge causes a horizontal tear as it works its way back.
Initial treatment of a meniscal tear follows the basic RICE formula (rest, ice, compression and elevation) combined with non-steroidal anti-inflammatory medications for pain. If your knee is stable and does not lock, this conservative treatment may be all you need. Blood vessels feed the outer edges of the meniscus, giving that part the potential to heal on its own. Small tears on the outer edges often heal themselves with rest.
If your meniscal tear does not heal on its own and your knee becomes painful, stiff or locked, you may need surgical repair. Depending upon the type of tear, whether you also have an injured ACL, your age and other factors, your doctor may use an arthroscope to trim off damaged pieces of cartilage.
A cast or brace is used to immobilise your knee after surgery. You must complete a course of rehabilitation exercises before gradually resuming your activity.