LCL injuries can occur in several ways:

• Contact Injuries: Getting hit on the inside of your leg like during a tackle, a car accident, or twisting injuries.
• Noncontact Injuries: Falling on a knee that’s bent backward.

These injuries can cause the outside of the knee to open up too much or make the lower leg rotate outward more than it should.

Sometimes, the common peroneal nerve, which is close to the LCL, can also be hurt. This can lead to serious issues like a “foot drop,” where you can’t lift your foot or toes up. If the nerve is damaged, it might need surgery to help with walking.

• Pain: Pain on the outside of the knee, which can be mild to severe.
• Swelling: The knee might swell up.
• Stiffness: The knee may feel stiff and hard to bend or straighten.
• Instability: The knee might feel unstable, like it could give way, especially when moving side-to-side or walking.
• Difficulty Moving: Problems with stopping quickly or changing direction.
• Bruising: Bruises may appear on the outer side of the knee.
• Walking abnormalities: Walking can be painful, difficult or uneasy, especially with severe injuries.
• Popping or Clicking: You might hear or feel a popping or clicking when the injury happens, followed by pain and swelling.

To figure out if you have an LCL injury, doctors will:

• Examine Your Knee: Check how it moves and where it hurts. We perform stress testing at different range of motions to see if the LCL provides restraint.
• Take Special X-rays: A varus stress x-ray helps measure how much the knee opens up on the outside. We like to compare this to the uninjured knee.
• Use MRI: An MRI gives detailed images to show how bad the injury is and if there are other problems with ligaments, menisci (cartilage), or the joint itself.