What is a Knee Sprain: When one of the knee ligaments overstretches which tears some of the fibres
Symptoms: knee ligament pain, swelling, instability, difficulty bending and straightening the knee
Causes: force through the knee or sudden twisting
Treatment: PRICE, exercises. Occasionally surgery is required
Other names: Ligament tear, knee strain
There are 4 ligaments in the knee joint. In the centre of the joint are the two cruciate ligaments - anterior and posterior (ACL & PCL). At the sides of the joints are the two collateral ligaments - the medial and lateral (MCL & LCL). They work together to keep the knee joint stable and protect it from injury.
A knee sprain simply means that one of the
has been overstretched and that some or all of the fibres have been
damaged. This usually occurs when there is a force through the knee eg a
tackle in sport or sudden twisting of the knee eg when falling
There are 3 grades of knee sprains:
Grade 1: a few fibres (less than 10%) are damaged/torn. Usually heals naturally
Grade 2: more fibres are torn but the ligament is still intact.
Grade 3: the ligament is ruptured ie completely torn. May require surgery
The most common symptoms of a sprained knee are pain, swelling and bruising. With more severe injuries, there may also be some instability around the knee causing it to give way. Symptoms may develop immediately after an injury, but sometimes they don’t appear until a couple of days later.
If you are given a diagnosis of a sprained knee, it is worth asking some questions to find out more.
What you want to know is:
1) Which ligament is damaged?
2) What grade knee sprain is it?
3) What treatment do they recommend?
The location of the pain can help to determine which knee ligament you have sprained. Medial knee pain (inner side of the knee) usually indicates a Medial Collateral Ligament (MCL) sprain – this is the most common, also called an MCL tear. Pain on the outer side of the knee usually indicates a Lateral Collateral Ligament sprain.
1) PRICE: Usually, the best course of action is to follow the PRICE principles (Protect, Rest, Ice, Compress, Elevate) to reduce pain and swelling and to speed up healing. Click the link to find out how to safely and effectively use PRICE.
2) Rehab: Then when you feel able (usually in just a few days), start some exercises to regain the strength, movement and function of your knee. For guidance on exercises and how to progress them appropriately to get back to full function following a sprain visit the knee strengthening exercises section.
3) Knee Brace: You might find that wearing a knee brace helps to reduce any pain and instability after a knee sprain. Usually a basic knee brace will be sufficient, costing as little as $4/£7. If you need a bit more support, advanced knee braces work well. Click the links to find out more about knee brace options.
If you have already been discharged by your doctor and all you have been told is that you have a sprained knee, it is almost certainly not too serious, and is likely a grade 1 or 2 sprain.
Grade 3 tears (also known as a rupture), can often be treated in the same way as grade 1 & 2 sprains, although they will take longer to heal. However, sometimes surgery is advisable if the knee keeps giving way, despite trying exercises.
The most common knee ligament to sprain is the MCL which causes medial
knee pain (inner side of the knee) - see the
page for more info. ACL injuries tend to be more serious but they are less common as it takes a great deal of force to injure the ACL. Visit the ACL injuries page to find out more.
There are a number if different causes of knee pain, some that come on following a specific incident, others build up gradually with no obvious cause.
If your knee pain was caused by a specific incident such as a fall, visit the Common Knee Injuries section. If your knee pain has come on gradually over time, go to the Common Knee Conditions section.
If you want help working out what is wrong with your knee, visit the Knee Pain Diagnosis section.