Anterior Cruciate Ligament (ACL) & Medial Collateral Ligament (MCL)

Sports like football are laden with knee injuries because they involve hits to the outside of the knee. Contact to the outside of the knee can cause meniscus tears, ACL tears and MCL tears to all occur at once.


The anterior cruciate ligament (ACL) attaches to the femur (thigh bone) and the tibia (shin bone), and essentially prevents the femur from sliding too far forward. Like other ligaments in the knee, the ACL provides stability and allows movement such as rotation of the knee. Injuries to the ACL cause both pain and swelling in the knee.

ACL tears lead to other injuries such as arthritis and cartilage tears. Because the ACL helps stabilize the knee, injuries to the ACL make the knee less stable. When the knee is less stable, sudden pivoting movements are extremely difficult and oftentimes lead to arthritis and cartilage tears.

Treatment for ACL Injuries

Once the ACL is completely torn, it cannot heal back together, even when the ends are sewn back together. The most common treatment for ACL tears is reconstructive surgery. Reconstructive surgery involves removal of the torn ends of the ACL and replacement of those ends with a graft. The graft is secured by tunnels that are made in the tibia and femur.


The medical collateral ligament (MCL) is located in the inside of the knee joint and functions to prevent the joint from opening up. Like the ACL, the MCL attaches to both the femur and tibia and controls stability in the knee. Injuries to the MCL involve pain and swelling in the knee.

Usually, MCL injuries occur when the knee joint buckles after being hit. Because it functions to prevent the inside of the knee joint from opening up, pressure to the outside of the knee can injure the MCL. In addition to hits to the outside of the knee, stretching the MCL too far can also cause it to tear.

Treatment for MCL Injuries

MCL injuries heal quickly and rarely require surgery. Resting the knee, icing the injury and taking anti-inflamatory medications can help the injury heal more quickly.

Severe sprains to the MCL sometimes require a knee brace. Usually, even patients with knee braces are able to resume normal activity and athletic activity as soon as they are no longer experiencing pain. If the injury is even more severe, physical therapy and a 3 to 4 month break from normal activity is required.