Medial collateral ligament (MCL) injury
Expert review by: Mr Damian McClelland, Trauma and Orthopaedic Consultant and Clinical Director for Musculoskeletal Services at Bupa
A medial collateral ligament (MCL) injury is when you damage 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.
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 ligament is stretched but still intact, this is called an MCL sprain. Sprains are given different grades depending on how severe they are.
An MCL injury is a common knee ligament injury. It’s also 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 can happen if you get a direct blow to the outside of your leg, often during sports such as rugby. You can also injure your MCL by twisting your knee, for instance while skiing, and from repeated stress on your knee, which can happen while swimming breast stroke, for example. You can also injure your MCL if you fall.
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.
Depending on how severe your injury is, your knee may feel unstable or loose, like it may give way. 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. And you may get some bruising – it can take one to three days after your injury for this to appear.
Self-help for medial collateral ligament injury
It’s a good idea to follow the POLICE procedure after an MCL injury. POLICE stands for the following.
Protect. Protect your injury from further damage. Rest immediately after the injury but not for long (usually up to two to three days). You might find it helps to use some form of support or crutches.
Optimal Loading. Get active sooner rather than later. Start to put weight on your knee and build up your range of movement. Do this gradually – be guided by what feels right for you.
Ice. Place a cold compress, such as a bag of ice or frozen peas wrapped in a towel onto your knee. Do this for around 20 minutes every couple of hours for the first two to three days.
Compression. Wrap an elasticated bandage around your knee to help reduce swelling.
Elevation. Elevate your knee above the level of your heart to reduce swelling. Sit or lie on a chair and use a cushion to raise your leg.
Infographic: POLICE principles
Bupa's POLICE infographic (PDF, 0.5 MB) below illustrates the ‘POLICE principles’ to reduce your pain and help you to recover.
There are certain things it’s best to 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 the following.
Heat. Don’t have hot baths, showers, or saunas, and avoid heat packs and rubs.
Alcohol. If you drink alcohol, it can slow down your recovery and mask your symptoms – this can increase the risk that you’ll injure yourself again.
Running. Don’t run or do any other form of moderate exercise.
Massage. Massaging the affected areas can cause more swelling and damage, so don’t do this for the first day or two.
Infographic: HARM principle
Bupa's HARM infographic (PDF, 0.6 MB) below illustrates the ‘HARM principle' of things you should avoid doing in the first three days after your injury.
Both POLICE and HARM are measures you can use to treat any type of soft tissue injury to your knee, not just an MCL injury.
If you’re finding it difficult to put 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 physiotherapist will explain how long you’ll need to use this for.
Treatments for medial collateral ligament (MCL) injury
If you’re worried that you've injured your knee, contact a medical professional who can examine it for you. They may suggest you have an X-ray of your knee. They may refer you to a specialist doctor, who may organise investigations such as an MRI scan, and any further treatment you may need.
Your medial collateral ligament injury treatment will depend on how severe the damage is. The first priority is to control your pain and swelling using the POLICE and HARM self-help measures (see our above section on self-help). Other 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 MCL injury 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 more severe. 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 a pharmacist or your GP for advice.
Physiotherapy for medial collateral ligament injury
A physiotherapist will assess your knee and plan a programme of medial collateral ligament injury exercises to suit your individual needs and rehabilitate your knee. 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 MCL recovery exercises because they will be an important part of your MCL injury recovery. Often, knee bracing and treatment with physiotherapy will be all you need if you have an MCL sprain.
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
Looking for physiotherapy?
You can access a range of treatments on a pay as you go basis, including physiotherapy.
To book or to make an enquiry, call us on 0370 218 6528∧
How long it takes a medial collateral ligament to heal depends on how severe your injury is. If you have a mild sprain, your MCL will usually recover after about two to three weeks. Then you can return to your normal activities, including sports. If you have a severe sprain, you can return to your activities after about four weeks. If you have a severe injury and have torn your ligament, it can take six to 12 weeks, or even longer to recover.
You’ll usually be able to walk with a torn MCL but it depends how severe your injury is. If you’re finding it difficult to put weight on your knee, you may need to use crutches or wear a brace to support you for a while.
For more information, see our section on self-help for medial collateral ligament injury.
Symptoms of an MCL injury will depend on how severe it is but may include:
- pain on the inside of your knee
- tenderness
- swelling
- bruising
For more information, see our section on symptoms of medial collateral ligament injury.
If you’ve injured your MCL, you’ll probably have some pain on the inside of your knee, and it may feel tender too. You’ll most likely still be able to walk on it but it’s possible that your knee may feel unstable and like it may give way. You may have some swelling and bruising, but you don’t always get this with an MCL injury.
For more information, see our section on symptoms of medial collateral ligament injury.
Posterior cruciate ligament (PCL) injury
With a PCL injury, it’s common to injure other ligaments, or other parts of your knee, at the same time.
Anterior cruciate ligament (ACL) injury
An ACL injury can be a partial or a complete tear, an overstretch, or a detachment of the ligament.
Lateral collateral ligament (LCL) injury
An LCL injury is often associated with injuries to the ligaments and tendons in this area, as well as to other parts of the knee.
Meniscal tear
Tears of the menisci are a common injury. When people talk about a ‘torn cartilage’ in their knee they usually mean a meniscus injury.
Patellar tendinopathy (jumper's knee)
Patellar tendinopathy is also called ‘jumper’s knee’ because the injury commonly occurs during sports that involve jumping, such as basketball.
Patellofemoral pain syndrome
Patellofemoral pain syndrome is sometimes called ‘runner’s knee’ because it’s particularly common in people who run or do other sports.
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- Medial collateral ligament injury. BMJ Best Practice. bestpractice.bmj.com, last reviewed 29 April 2025
- Naqvi U, Sherman AL. Medial collateral ligament knee injuries. StatPearls Publishing. www.ncbi.nlm.nih.gov/books, last updated 17 July 2023
- Sprains and strains. NICE Clinical Knowledge Summaries. cks.nice.org.uk, last revised September 2020
- Knee ligament injuries. Patient. patient.info, last edited 10 February 2023
- Non-steroidal anti-inflammatory drugs. NICE British National Formulary. bnf.nice.org.uk, last updated 30 April 2025
Content review by:
Rachael Mayfield-Blake , Freelance Health Editor
Page created June 2025
Next review date: June 2028
