Medial collateral ligament (MCL) injury

Expert reviewer, Mr Damian McClelland, Trauma and Orthopaedic Consultant, and Clinical Director for Musculoskeletal Services at Bupa
Next review due December 2023

The medial collateral ligament (MCL) is one of the ligaments inside your knee. The MCL lies on the inner side of your knee joint, and connects your thigh bone (femur) to your shin bone (tibia). An MCL injury can be a partial or a complete tear, a stretched ligament or a detachment of the ligament from your bone.

An image showing the different parts of the knee

About medial collateral ligament (MCL) injury

Along with the other ligaments in your knee, your MCL keeps your knee stable. Your MCL and your lateral collateral ligament control the sideways movement of your knee.

When the knee ligaments are stretched but not torn, this is called a sprain. Sprains are given different grades depending on how severe they are. The MCL is the most commonly injured knee ligament, often during sports such as rugby. It’s common to injure one of your cruciate ligaments, or your meniscus, at the same time as your MCL.

Causes of medial collateral ligament (MCL) injury

An MCL injury is usually caused by your knee being pushed inwards (towards your other knee). This may happen if you have a direct blow to the outside of your leg, which can happen during sports such as rugby. You can also injure your MCL by twisting your knee; for instance, in skiing, or from repeated stress on your knee – such as in breast stroke when swimming. You can also injure the MCL if you fall.

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Symptoms of medial collateral ligament injury

If you’ve injured your MCL, you’ll probably have some pain on the inside of your knee. This area may be tender to the touch too. If your injury isn’t too severe, you’ll probably still be able to walk on it. You may have some swelling, but you don’t always get this with an MCL injury. Depending on how severe your injury is, your knee may also feel a little unstable and feel like it may give way. You may get some bruising in the first few days after your injury.

Self-help for medial collateral ligament injury

If you injure your knee, you should follow the POLICE procedure to manage any type of soft tissue injury to your knee. POLICE stands for protect, optimal loading, ice, compression and elevation.

Additionally, there are certain things you should avoid in the first three days after your injury so you don’t damage your knee further. These can be remembered as HARM, which stands for heat, alcohol, running and massage.

To find out more about POLICE and HARM, you can visit our page on what to do if you injure your knee.

If you’re having difficulty bearing weight on your knee, you may need to use crutches or wear a brace to support you for a while. It’s common to wear a leg brace for several weeks after an MCL injury, particularly if your injury is severe. Your doctor or physio will explain how long you’ll need to use this for.

Treatments for medial collateral ligament (MCL) injury

You’ll usually need to go to A&E with this kind of injury, where they’ll examine you and take some X-rays of your knee. They may then refer you to an acute knee clinic, which will organise any investigations and treatment you need.

The treatment you’ll be offered for your MCL injury will depend on how severe the damage is. The initial treatment will be to control your pain and swelling using the POLICE and HARM self-help measures (see above). Further treatments may include knee bracing, physiotherapy, medicines and occasionally, surgery.

You may see an orthopaedic surgeon (a doctor who specialises in bone surgery) or a sports medicine professional, such as a sports doctor or a physiotherapist. There are different treatments that your doctor or physiotherapist may suggest, and a lot that you can do yourself to help your recovery.

Medicines for medial collateral ligament injury

You can take over-the-counter painkillers, such as paracetamol or ibuprofen, to help relieve your pain. Your doctor may prescribe stronger painkillers if your pain is really bad. As well as easing your pain, non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen may help to reduce any inflammation and swelling. Always read the patient information that comes with your medicine, and if you have questions, ask your pharmacist or GP for advice.

Physiotherapy for medial collateral ligament injury

Your physiotherapist will carefully assess your knee and then plan a programme of rehabilitation exercises to suit your individual needs. The aim of physiotherapy is to help your knee recover its full range of movement, and its strength and stability. This should help you get full function back in your knee and return to your usual sports and activities. Make sure you do the exercises as they will be an important part of your recovery. Often, knee bracing and treatment with physiotherapy will be all you need if you have an MCL injury.

Surgery for medial collateral ligament injury

Most people recover from an MCL injury without needing to have surgery. But sometimes, surgery is the best option to repair an injury to the medial collateral ligament. This is most likely if:

  • more than one ligament or tissue in your knee is damaged
  • your knee remains unstable after physiotherapy

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Related information

    • Knee ligament injuries. PatientPro., last edited 15 February 2017
    • Acute knee injuries. Brukner & Khan’s Clinical Sports Medicine: Injuries, Volume 1, 5th ed (online). McGraw-Hill Medical., published 2017
    • Medial collateral knee ligament injury. Medscape., updated 31 May 2017
    • Medial collateral ligament injury. BMJ Best Practice., last reviewed 12 September 2020
    • Knee pain – assessment. NICE Clinical Knowledge Summaries., last revised July 2017
    • Sprains and strains. NICE Clinical Knowledge Summaries., last revised April 2020
    • Treatment of sports injuries. Brukner & Khan’s Clinical Sports Medicine: Injuries, Volume 1, 5th ed (online). McGraw-Hill Medical., published 2017
    • Treatment for knee pain. Chartered Society of Physiotherapy., last reviewed 26 March 2020
  • Reviewed by Rachael Mayfield-Blake, Freelance Health Editor, December 2020
    Expert reviewer, Mr Damian McClelland, Trauma and Orthopaedic Consultant, and Clinical Director for Musculoskeletal Services at Bupa
    Next review due December 2023