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Knee injuries

Key points

  • Knee injuries can cause pain, swelling, bruising and instability.
  • If you injure your knee, use PRICE (protect, rest, ice, compression, elevation) for the first two to three days.
  • See your GP within a day if your knee is very painful and you can't put your weight on it.
  • A physiotherapist can give you exercises to help your knee recover or you may need surgery.

Group of people jogging in the park - knee ligament injury information

Knee injuries are common, especially when taking part in sport. Injuries to soft tissues, such as ligaments, cartilage and tendons are the most common. You can also damage the bones that make up your knee joint.

About knee injuries

There are many different structures inside and outside your knee. These include:

  • ligaments, which connect your bones together
  • articular cartilage, which covers the ends of your shin bone and thigh bone
  • two crescent-shaped cartilage discs called menisci, which act as 'shock absorbers' and helps to stabilise your knee
  • tendons, which connect your muscles to your bone

Injury to your knee can damage any one or more of these structures.

Illustration of the different parts of the knee

Knee ligament injuries

Your knee ligaments help to keep your knee stable.

The medial collateral (MCL) and lateral collateral ligaments (LCL) are found on either side of your knee joint. They limit the amount your knee can move from side to side. You can sprain or tear your MCL if your lower leg gets forced outwards. For example this can happen when being tackled in rugby or when skiing. Your LCL is less commonly injured, and this is more likely to happen when you have also damaged other ligaments.

Your anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) form a cross (cruciate) inside your knee. They help to keep your knee stable. ACL injuries are one of the most serious types of knee injury.

If you have injured your MCL or LCL, your GP may grade your injury according to how severe the damage is.

  • Grade 1 is a stretch of the ligament without tearing.
  • Grade 2 is a partial tear of the ligament.
  • Grade 3 is a complete tear through the ligament.

Other soft tissue injuries

There are other soft tissues around your knee that can be injured. Soft tissue means any tissue in your body that isn't bone.

Tearing the meniscus in your knee is one of the most common knee injuries. You can damage it if you play a sport that involves twisting your upper leg while your foot is planted on the ground. As you get older, your meniscus may become worn. This makes it more likely to tear after a minor injury or just getting out of a chair awkwardly.

If you’re a regular runner or take part in sports where you jump a lot, you may hurt your knee. You can irritate or tear the tendon that connects your kneecap (patella) to your thigh muscle. This tendon is called the quadriceps tendon. Or you may irritate soft tissue around your kneecap, including the patellar tendon, which is just below your knee cap (Jumper’s Knee).

Symptoms of knee injuries

You may feel or hear a popping or snapping when the injury happens. You may also find that you can't put your full weight on the injured leg.

The symptoms for most ligament injuries will be similar. These include:

  • pain
  • swelling
  • instability – you may feel like your knee is giving way

If you injure the meniscus in your knee, you may feel a locking sensation and severe pain. Pain may develop towards the inside or outside of your knee joint and you may see some swelling.

If you have injured your knee and you think it’s more than a simple sprain, visit your GP or physiotherapist. Seek advice if it’s tender to the touch, very stiff, swollen, giving way, clicking painfully, locking or you can’t put your full weight on it.

Causes of knee injuries

You may injure your knee if:

  • an impact moves your knee beyond its usual range of movement, for example, if you have a fall or land awkwardly
  • you play a sport that combines running, jumping and stopping with quick changes of direction, such as football
  • you have a condition such as arthritis or gout, which can affect your joints, or are very overweight, which can put pressure on your knees
  • your knees hit the dashboard in a car accident – this is one way to damage the posterior cruciate ligament
  • your footwear is not right for your feet, your running style or the sport, or you have poor training methods or flexibility

Diagnosis of knee injuries

Your GP or physiotherapist will ask about your symptoms and examine you. This may include feeling for fluid in your knee joint by pressing gently around your kneecap. He or she will also ask you to describe how your injury happened, where your pain is and what type of pain it is.

Your GP or physiotherapist may ask you to walk, sit or lie down. This is so he or she can test for injury to your knee ligaments or soft tissues. He or she will bend and straighten your knee and move your leg into different positions.

Your doctor may refer you for other tests in a hospital or clinic, which may include:

  • an X-ray or CT scan – this may be used to check for a fracture or arthritis
  • an ultrasound - this may be used to look at the tendons in your knee
  • an MRI scan – this is the best all round test for injuries inside a joint to the cartilage or ligaments, and can also be used to identify stress fractures

Treatment of knee injuries

There are different types of treatment that your doctor or physiotherapist may suggest, depending on the type and severity of the damage to your knee. It’s important to be patient when recovering from a knee injury. Your injury may take time to fully repair itself, so you may not be able to do all the things you’re used to doing for some time. Different injuries require different rehabilitation, so it’s best to talk to your GP or physiotherapist.

Self help

You should follow the PRICE procedure for any soft tissue injury to your knee. PRICE stands for the following.

  • Protect your knee from further harm.
  • Rest your knee for the first two to three days, possibly using crutches. Then reintroduce movement so that it doesn’t become stiff and you don't lose muscle strength.
  • Ice the painful area with a cold compress such as ice or a bag of frozen peas wrapped in a towel. This will help reduce swelling and bruising. Do this for 15 to 20 minutes every two to three hours. Don't apply ice directly to your skin as it can damage it.
  • Compress the joint with an elastic bandage or Tubigrip to support the knee and help decrease swelling. Don’t leave the bandage on while you sleep.
  • Elevate your knee by resting it above the level of your heart and keep it supported.

There are certain things you shouldn’t do in the first three days after your injury so you don’t damage your knee further. You can remember these as HARM.

  • Heat. Don’t take hot baths, showers or saunas, or use a heat pack.
  • Alcohol. Drinking alcohol can increase bleeding and swelling in the affected area.
  • Running or other forms of exercise, which may cause further damage.
  • Massaging the injured knee. This can cause more swelling or bleeding.


You can buy over-the-counter painkillers such as paracetamol to treat mild and moderate pain. Over-the-counter non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen can help to reduce inflammation and swelling, as well as relieve pain. NSAIDs are available as gels, creams and sprays that you can put directly onto your skin, as well as tablets that you take by mouth.

Your GP may prescribe stronger painkillers if your pain is severe. Always read the patient information that comes with your medicine and if you have questions, ask your pharmacist or doctor for advice.


If your injury is more severe or complex, your GP may refer you to a physiotherapist (a health professional who specialises in movement and mobility). You can also choose to see a physiotherapist privately. He or she will develop a programme of rehabilitation exercises to gradually strengthen your knee and stretch your muscles. These exercises will vary depending on the type of injury you have and how severe it is.

Some people have braces or strapping to support the knee during rehabilitation, usually when an injury has been severe.


For some types of knee injury, your GP or physiotherapist may recommend that you have surgery to repair the damage to your knee – especially if other forms of treatment haven’t worked. Your GP will refer you to an orthopaedic surgeon for assessment.

The surgeon is more likely to suggest surgery if you have one of the following injuries.

  • You have torn your ACL and you do a lot of sport or have also torn the meniscus. ACL reconstruction involves taking a piece of tendon (usually from your hamstring) to replace the damaged ligament.
  • Your knee remains painful or locks after an injury to your meniscus.

You may be able to have a type of keyhole surgery called knee arthroscopy to access the damaged area of your knee. Rarely, surgery may involve opening up your knee joint to repair it.

Prevention of knee injuries

There are some precautions you can take to try to reduce the risk of damaging your knee ligaments.

  • Exercise regularly to maintain a good level of fitness, and include some resistance training (training with weights). This will mean your muscles are stronger and better able to support your joints, including your knees. If you haven't been active for a while, start gently and gradually increase the intensity.
  • Spend five to 10 minutes warming up before doing any exercise to increase blood flow to your muscles and reduce the chance of an injury. Most sports professionals advise stretching your muscles after warming up and again after cooling down. There is little evidence to show that stretching before or after exercise reduces injuries, but staying flexible is important for everybody.
  • Wear the right footwear. There are many different models of trainers available and it’s important to find some that fit well and offer the support and cushioning you need. If you’re not sure, it’s a good idea to go along to a specialist sports shop and ask for advice.


 Reviewed by Natalie Heaton, Bupa Health Information Team, 30 August 2013.

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  • This information was published by Bupa's Health Information Team and is based on reputable sources of medical evidence. It has been reviewed by appropriate medical or clinical professionals. Photos are only for illustrative purposes and do not reflect every presentation of a condition. The content is intended only for general information and does not replace the need for personal advice from a qualified health professional. For more details on how we produce our content and its sources, visit the about our health information page.

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