Meniscus tear

The meniscus is a thick pad of smooth cartilage in your knee that sits between the ends of your shinbone and thigh bone. There are two pads in each knee joint and their main functions are to:

• Act as a shock absorber
• Help your knee glide smoothly
• Keep your knee stable

Meniscus cartilage is tough and elastic but can be torn or damaged through trauma or because it’s weakened with wear and tear as you age. It is one of the most common knee injuries. A tear will almost always affect the function of your knee and your ability to continue with many activities until it recovers or is repaired.

There are two main causes:

• Any sudden or forceful rotation or flexing of your knee eg when playing contact sports such as rugby and non-contact sports such as football and volleyball — this is why meniscus tears are common in younger people and athletes who are more active, and often occur with other knee injuries such as anterior cruciate ligament (ACL) sprains or tears 
• Wear and tear and the natural ageing of the cartilage — this is common in people aged over 40, including older athletes, and more than four in 10 people aged over 65 have experienced a meniscus tear

A meniscus tear can also be caused by deep squatting, kneeling or lifting something heavy.

Your symptoms may be mild at first, allowing you to continue with your activity. However, as inflammation increases, your knee will hurt more and stop you from continuing. 

The most common symptoms are:

• Crepitus
• Difficulty fully straightening your leg
• Knee pain — particularly when twisting your knee or squatting, although it may stop when resting; it may be across the middle of your knee or your whole knee
• Popping sensation
• Stiffness or restricted movement
• Swelling

Other symptoms include:

• Feeling that your knee is giving way
• Osteoarthritis — a meniscus tear can lead to this over time
• Your knee ‘locking’ in place  — locking up can be caused by a shredded piece of cartilage getting caught in your knee joint

Risk factors for a meniscus tear

Risk factors include: 

• Age — wear and tear over time increases your risk of a meniscus tear
• Being an athlete — especially in sports such as basketball, tennis or football where you have to suddenly change direction while running
• Obesity — this puts more strain on your knees
• Performing activities involving aggressive pivoting or twisting of your knee 

Complications of a meniscus tear

A meniscus tear can make you feel that your knee is giving way and restrict the movement of your knee. It can lead to persistent knee pain and increase your risk of osteoarthritis in the affected knee.

See your GP if your knee is: 

• Not able to move normally 
• Painful 
• Swollen

Your GP should be able to give you a diagnosis from a simple examination. They'll ask you if there's anything you may have done to cause a meniscus tear, such as a sports injury, and make a physical assessment of your knee. This involves gently moving your knee and leg into different positions and watching you walk and squat if you can.

They may also recommend that you go for an X-ray or MRI scan to rule out other conditions. An X-ray can’t detect a meniscus tear as the meniscus is made of cartilage, not bone, but it can rule out other knee problems with similar symptoms. An MRI scan uses radio waves and a strong magnetic field to create detailed images of both soft and hard tissues in your knee and will detect a meniscus tear.

Treatment of your meniscus tear depends on:

• Its location — tears in the outer part of the meniscus often heal on their own as this area has a good blood supply, which helps healing, while tears in the inner part of the meniscus do not heal on their own as this area has a poor blood supply
• Its size 
• Other related injuries
• Your activity level
• Your age

In most cases, a torn meniscus will recover on its own, particularly in younger people. To allow this to happen you should:

• Rest your knee — avoid activities that involve pivoting, rotating or twisting your knee or activities that worsen your knee pain; if you have severe knee pain, using crutches can relieve some of the pressure on your knee to aid healing
• Use anti-inflammatory painkillers
• Use ice packs to reduce swelling — try applying a bag of frozen vegetables, a cold pack or a towel filled with ice cubes for 15 minutes while keeping your knee elevated; repeat this every four to six hours for the first one to two days and then as often as you need

If your meniscus tear is associated with arthritis, treatment for your arthritis will often help you recover from your meniscus tear over time. If your meniscus tear is not associated with poor knee movement or locking of your knee, it will also often improve over time without any intervention. Surgery is therefore not usually needed. 

Where a meniscus tear is caused by ageing, symptoms often come and go and your GP will usually advise you to rest your knee and use painkillers at these times. Physical therapy can also help by strengthening the muscles in your legs and around your knee, which helps stabilise and support your knee joint. 

Cartilage is a tough, protective material that is designed to protect bones for a lifetime. It doesn’t repair or regenerate itself easily so treatment is often about managing symptoms.

Surgery

Your doctor may recommend surgery if your knee is ‘locked’. This will be performed by arthroscopy, where your consultant uses telescopic instruments to look inside the knee and remove any meniscus cartilage that's preventing movement of your knee joint.

Sometimes, torn meniscus cartilage can be repaired using sutures or stitches to hold it together. Surgeons are also developing new techniques to transplant cartilage.

After your surgery, you will need to perform exercises to strengthen the muscles in and around your knee, which will help stabilise it. In 85-90% of people who have meniscus tear surgery, the short-term results are very good. 

However, if you have a large meniscus tear, in the long term you will have a greater risk of developing arthritis in your affected knee. If you have advanced arthritis, your doctor may recommend knee replacement surgery. If you are younger and experience symptoms of arthritis in your knee but do not have advanced arthritis, your doctor may recommend a meniscus transplant surgery. 

Preventing a meniscus tear

Meniscus tears often occur by accident, which makes them hard to prevent but you can take precautions to reduce your risk, including: 

• Avoiding sudden changes in the intensity of your workout
• Performing regular exercises to strengthen your thigh muscles and stay flexible
• Resting between workouts — tired muscles increase your risk of injury
• Warming up properly before rigorous activities
• Wearing shoes that fit properly and provide enough support