A collateral ligament injury in the knee is a common sports injury that can cause pain, swelling and a feeling of instability. The injury often occurs when twisting or changing direction quickly and can affect both everyday life and training. Here you will get a clear overview of symptoms, causes, when you should seek care and how the right support and rehabilitation can help you get back on track.
This injury guide covers injuries to the medial and lateral collateral ligaments of the knee. You can find more information about cruciate ligament injuries in our Injury Guide Anterior Cruciate Ligament Injury and Posterior Cruciate Ligament Injury.
What is a collateral ligament injury?
A collateral ligament injury means that one or more of the knee joint's stabilizing ligaments on the sides of the knee are stretched or torn. The most common injuries are to the medial collateral ligament (MCL), but also to the lateral collateral ligament (LCL). The injury often causes pain, swelling and a feeling that the knee is unstable or giving way.
Common causes & risk factors
Ligament injuries often occur in sports that involve rapid changes in direction, twisting, or tackling – such as soccer, handball, or skiing. Falls, missteps on uneven terrain, or sudden twisting movements can also cause injury. Previous knee injuries, muscle weakness, or impaired balance can increase the risk.
Symptoms
Symptoms include pain on the inside or outside of the knee, depending on which ligament is injured. Swelling can occur immediately or after a few hours. Many people experience instability, especially with lateral movements or when stepping on stairs and uneven terrain. In more severe injuries, the knee may give way or feel difficult to control.
When should you seek medical attention?
Contact a healthcare center if you suspect you have suffered a ligament injury. Injuries following trauma, especially with twisting force, should be investigated to assess the extent of the injury and rule out cruciate ligament or meniscal injuries.
Contact a health center immediately if you are in severe pain, cannot bear weight on your leg, and your knee is severely swollen. If the health center is closed, seek care at an emergency room.
Recommended protection & support
Knee braces with stabilizing splints on the sides can relieve the ligaments and improve stability during rehabilitation. Soft knee braces with compression can be used for milder injuries to reduce swelling and provide light support. Rehabilitation with a focus on regaining mobility in the knee and training strength in the thigh, hip and buttocks is central to creating a stable knee and reducing the risk of relapse. In the first weeks after the injury, exercises that stress the inside of the knee should be avoided (in case of damage to the medial collateral ligament). Seek the help of a physiotherapist for assistance with rehabilitation.
See all protection and supports that can stabilize knee ligament injuries
Related injuries
For more information about knee problems, you can find more articles in Injury Guide Knee. You can also go to the Injury Guide's main page to read about other injuries and symptoms.
