Knee AnatomyThe medial collateral ligament runs along the inner side of the knee to connect the bottom of the thighbone to the top of the shinbone. It provides stability and strength to the inner side of the knee joint. A blow to the outside of the knee may cause injury to the MCL. This can result in a stretch or tear to the ligament. These types of injuries are common in contact sports.

Depending on the level of the pain or looseness to the ligament, the injury is classified in different grades:

  • Grade 1 MCL Injury:¬† A patient experiencing some tenderness and minor pain has most likely stretched the MCL ligament.
  • Grade 2 MCL Injury: The presence of major pain, tenderness on the inside of the knee and some knee joint instability could indicate that the MCL ligament has been partially torn.
  • Grade 3 MCL Injury: An injury at this level produces severe pain and tenderness at the inside of the knee, including swelling and obvious joint instability. Your MCL ligament has been completely torn.


Treatment options depend on the severity of the MCL injury. Conservative treatment is usually effective if the medial collateral ligament (MCL) has a small partial tear: RICE: Rest, Ice, Compression, Elevation. To further protect the knee, the physician may recommend crutches to keep weight off your injured knee. For Grade 2 and 3 injuries, the physician may recommend physical therapy and an exercise program. This can promote healing and restore knee strength.

Although severe MCL injuries usually respond well to nonsurgical treatment, the physician may suggest surgery. If the collateral ligament is torn in such a way that it cannot heal or if it associates with other ligament injuries, surgery may be the option. Sometimes, your ligament may tear where it attaches to your shinbone or thighbone. In this case, the surgeon will reattach the ligament to the bone using stitches, a metal screw or bone staple. If the tear is in the middle of the ligament, the surgeon will sew the torn ends together.