An MCL tear is a knee injury that can occur when the medial collateral ligament, which is a major ligament located on the inner side of the knee, is damaged. The injury can range from a mild sprain or partial tear to a complete grade 3 rupture. MCL tears are most common in people who play sports like football, basketball, skiing, and martial arts. The severity of the tear is classified into three grades:

• Grade 1: A grade 1 MCL tear is a minor tear in which your MCL is stretched but not torn. You may experience mild pain and swelling, but your knee will still feel stable.

• Grade 2: A grade 2 MCL tear is a moderate tear in which your MCL is partially torn, usually the superficial part of your MCL. Your knee will likely be loose when it’s moved by hand, and you’ll probably have intense pain and tenderness along the inner side of your knee.

• Grade 3: A grade 3 MCL tear is a severe tear in which your MCL is completely torn, both the superficial and deep parts. Your knee will likely be very unstable and loose, and you’ll probably experience intense pain and tenderness. It’s common for someone to have other knee injuries, especially damage to their anterior cruciate ligament (ACL), if they have a grade 3 MCL tear.

MCL tears are usually caused by getting struck in your knee or by bending or twisting the joint too forcefully, causing the ligament to stretch and tear. Wear and tear of the ligament over time through repeated stress and pressure, such as lifting heavy objects, can also contribute to MCL tears. Treatment for MCL tears usually involves using crutches to limit the amount of weight you put on your affected knee[[4]](https://www.ucsfhealth.org/conditions/mcl-tea...