Knee > LCL Tear

What is the Lateral Collateral Ligament?

The LCL (lateral collateral ligament) is a thin band of tissue that runs along the outside of the knee and connects the thighbone (femur) to the fibula, which is the small bone that runs down the side of the knee and connects to the ankle. Similar to the MCL (medial collateral ligament), the LCL's primary function is to stabilize the knee as it moves through its arc of motion.

Tears to the LCL commonly occur as a result of direct blows to the inside of the knee, which can over-stretch the ligaments on the outside of the knee and, in some cases, cause them to tear. The tear can occur in the middle of the ligament or at either end. The ligament can also be injured through repeated stress, which can cause it to lose its normal elasticity. Most knee injuries are to the ligaments that support the knee, not the knee joint itself. In rare cases, LCL tears in children produce breaks of the thighbone (femur) or shinbone (tibia), called epiphyseal fractures, which require surgery.

LCL tears occur in sports that require a lot of quick stops and turns, such as soccer, basketball, and skiing, or in sports in which there are violent collisions, such as football or hockey.

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. Grade 3 injuries often require surgery.

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

Your doctor will 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 doctor 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, in order to determine the severity 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 1: Some tenderness and minor pain at the point of the injury. This indicates that there have been small tears within the ligament.

   Grade 2: 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. This indicates that there have been larger tears within the ligament, but the ligament is not completely torn.

   Grade 3: 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 3 LCL tear means the ligament is completely torn, and often occurs in combination with a tear of the ACL (anterior 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

Should your physician require a closer look, these tests may be conducted:

   MRI (magnetic resonance imaging) has a greater than 90 percent accuracy rate in assessing the severity of LCL injuries, and is commonly used if the physical examination does not yield a satisfactory diagnosis. A stress X-ray may also 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. Anesthesia may be required to obtain such a view.

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