Knee > PCL Tear

What is the Posterior Cruciate Ligament?

The PCL (posterior cruciate ligament) is about two inches long and connects the thighbone (femur) to the shinbone (tibia) deep in the rear of the knee. It limits the backward motion of the knee, preventing the knee from hyperextending (bending the "wrong" way). When the knee is twisted or hyperextended, or there is a violent blow to the front of the knee while it is bent, the PCL can be torn, leaving the knee unstable and possibly unable to support a person's full weight.

The PCL (posterior cruciate ligament) is about two inches long and connects the thighbone (femur) to the shinbone (tibia) deep in the rear of the knee. It limits the backward motion of the knee, preventing the knee from hyperextending (bending the "wrong" way). When the knee is twisted or hyperextended, or there is a violent blow to the front of the knee while it is bent, the PCL can be torn, leaving the knee unstable and possibly unable to support a person's full weight.

PCL tears are infrequently caused by sports injuries. Because the PCL is the strongest of the knee ligaments, and because it is located deep inside the knee, tears are most often associated with traumatic injuries such as those resulting from car accidents. A tear can happen when the knee is violently forced backward with the leg straight, or when it is hit directly in front of the knee while the knee is bent, such as might happen to someone's knee striking a dashboard during a car accident. Because a violent blow to the knee is usually needed to tear the PCL, the injury is usually accompanied by injuries to other knee ligaments. A tear of the PCL without other ligament damage is extremely rare. Though rare in sports, PCL tears can occur when playing soccer, football, or other sports in which it is possible for the knee to receive a severe frontal blow.

Isolated PCL tears are frequently treated with rehabilitation rather than with surgery. However, surgery is typically considered when PCL tears are accompanied by other ligament injuries. Deciding whether to have or to forego surgery to repair a torn PCL may be partly a personal choice, but age, physical condition, and athletic goals may also play a role in the decision. Those who are not very active may choose an exercise strengthening program instead of surgery, since the injury is not likely to interfere with their daily activities. Such a program can take as long as six months to complete.

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

PHYSICAL EXAMINATION

Because the PCL is deep inside the knee, it is difficult to feel around in search of pain or tenderness. Here are two things that will probably be done in examining your possible torn PCL:

   With the knee bent 90 degrees, the doctor will push the shinbone (tibia) back in what is called a posterior drawer test. If the tibia moves excessively backward, that would strongly suggest a torn PCL.

   Ligaments and tendons do not show up on X-rays, but X-rays of your knee may be taken to rule out any fracture or dislocation.

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

   MRI (magnetic resonance imaging) has an accuracy rate of nearly 90 percent in determining whether a PCL has been torn and to what extent it has been damaged. While it shows the soft tissues, it is not very good at showing the details of a partial tear. MRI is painless and does not require any needles or dyes.

   Arthroscopic surgery, in which the doctor inserts a tiny camera into your knee, is the best way to examine a partial tear. Arthroscopy allows the physician to examine the PCL to determine the extent of the tear. This is done on an outpatient basis.

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