Knee > MCL Tear

What is the Medial Collateral Ligament?

The MCL (medial collateral ligament) is a broad, thick band of tissue that runs down the inner part of the knee, from the thighbone (femur) to about four to six inches from the top of the shinbone (tibia). The MCL's primary function is to prevent the leg from hyperextending inward, but it also is part of the mechanism that stabilizes the knee and allows it to rotate.

Injuries to the MCL commonly occur as a result of direct blows to the outside of the knee, which can over-stretch the ligaments on the inside of the knee and, in some cases, cause them to tear. The tear can occur in the middle or at either end of the ligament. It is not uncommon for athletes to suffer tears of the MCL and ACL (anterior cruciate ligament) at the same time. The ligament also can be injured through repeated stress, which can cause it to lose its normal elasticity, not unlike a worn-out rubber band.

The MCL usually is injured by direct contact to the outside of the knee. A perfect example is a clip block in football, in which one player collides with another player from the side. MCL tears also occur in sports where there are a lot of quick stops and turns, such as soccer, basketball, and skiing. Slipping on ice, if your lower leg splays outward, can produce the same result.

If the torn ligament does not heal sufficiently to provide proper support for the knee, you may experience instability in the joint, and you will be more susceptible to re-injury. Most MCL injuries are treated with braces. However, in rare cases, surgery may be required.

There are usually three parts to an orthopedic evaluation: medical history, physical examination, and tests your physician may order.

Your doctor will likely ask you how you injured your knee, how it has been feeling since the injury, and if your knee has been previously injured. Physicians also typically ask about other conditions, such as diabetes and allergies, and medications currently being taken. You may also be asked about your physical and athletic goals - information that will help the doctor decide what treatment might be best for you in achieving those goals.

Your physician will check for pain or tenderness along the inside of the knee, and will exert pressure on the outside of your knee while your leg is bent and straight, to approximate the cause of the injury. Depending on the degree of pain or looseness of your knee joint, the injury will be classified as one of three grades:

   Grade one: some tenderness and minor pain at the point of the injury.

   Grade two: noticeable looseness in the knee (the knee "opening up" approximately five millimeters) when manipulated by hand; major pain and tenderness at the inside of the knee; swelling, in some cases.

   Grade three: considerable pain and tenderness at the inside of the knee; some swelling and marked joint instability. The knee opens up approximately one centimeter when manipulated. A grade three MCL tear often occurs in conjunction with a tear of the ACL (anterior cruciate ligament) or, more rarely, the PCL (posterior cruciate ligament).

In some cases, your immediate pain and swelling may make it too difficult for your physician to accurately gauge the severity of the injury. If this occurs, you may be asked to wear a light splint and ice and elevate your knee until the swelling and pain lessen, so that an accurate diagnosis can be made.

TESTS

MRI (magnetic resonance imaging) has a greater than 90 percent accuracy rate in assessing the severity of MCL injuries, and is commonly used if the physical examination does not yield a satisfactory diagnosis. A stress X-ray rarely will be used to look for ligament tears. This test is like a normal X-ray, except that the doctor or technician will hold the knee open from the side so that any widening of the joint space will be evident on the X-ray.

   Imaging techniques