One of the key structures within the knee are the ligaments. Ligaments connect bone to bone and prevent excessive movement of the joint. They add stability to the joint and are extremely important in the knee joints function.


There are 4 main ligaments in the knee:
These are:
  • The Anterior Cruciate Ligament (ACL) – The Role of the ACL is to prevent hyperextension of the knee and stop forward movement of the shin bone in relation to the thigh bone.
  • The Posterior Cruciate Ligament (PCL) – The Role of the PCL is to prevent the thigh bone from slipping off the anterior edge of the shin bone. It also prevents the shin bone from displacing posterior to the thigh bone.
  • The Medial Collateral Ligament (MCL) – The Role of the MCL is to prevent the knee from overextending inwards.
  • The Lateral Collateral Ligament (LCL) – The Role of the LCL is to prevent the knee from overextending outwards.


These ligaments work in tandem to keep the knee joint stable throughout a whole range of movements and function. Problems arise when the knee is exposed to quick, sharp movements at the end of range of motion. A prime example of this is within footballers. Often players damage their knee ligaments when they go to turn direction quickly and the knee plants but gets stuck in the turf. This causes extreme torsion to the knee and can damage the ligaments.


When the ligaments are damaged it is categorized into 3 Grades.


Grade 1: This is when the ligament has been slightly overstretched but hasn’t lost its integrity and is still able to support the joint. You will experience localised pain around the ligament with some light swelling. It is advised that you ice around the painful area and avoid any impact/sudden movement of the joint. Timeframe for recovery 1-3 weeks.
Grade 2: This is when the ligament has been stretched to a point where it has caused significant damage. The knee may feel slightly unstable and a little “looser”. You will also have localised pain around the knee joint itself and more swelling than a Grade 1. It is advised that you ice around the sore points, rest the knee and see a rehabilitation therapist to complete the correct exercises. Timeframe for recovery 3-6 weeks
Grade 3: A Grade 3 is a complete rupture of the ligament. This means the tissue has been completely torn. You will often hear a “pop” or “snap”. Often the pain will be less than other grades as when you completely rupture the ligament it tears the nerves too. You will normally have swelling around the knee but will be able to function. Often the other ligaments will take up the slack so often people don’t realise they have done something serious. In Grade 3 ligament tears of the knee you will require surgery to reconstruct the ligament. This is often performed through keyhole surgery and the hamstring tendon is used to replace the ligament. It is advised you go see your GP and request further investigation/surgery. Timeframe for recovery 3 months +.



With all Grades rehabilitation is advised. Within your ligaments you have cells called proprioceptors. These control your joints placement within space. To explain this simply, when you place your leg down they ensure the knee is in the correct position. When you damage the ligament you also damage the proprioceptors.

This rehabilitation is key to ensure the knee functions correctly moving forwards. Often exercises completed on unstable surfaces such as wobble cushions work best. This helps to retrain the knee to correctly position itself during movement.

Overall women are more susceptible to knee ligament problems due to a higher Q angle. The Q angle relates to the width of the hips compared to the knee. Traditionally women have wider hips meaning a higher Q angle and more acute pressure through the knee. In terms of statistics women have an increased risk by about 20%.

On our next episode we will be covering one of the most common injuries worldwide, Runners Knee.


by Lewis from Fit2Function 


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