Posterior cruciate ligament (PCL) injury

Definition

A posterior cruciate ligament injury is a partial or complete tearing or stretching of any part of the posterior cruciate ligament (PCL).

Alternative Names

Cruciate ligament injury - posterior; PCL injury; Knee injury - posterior cruciate ligament (PCL); Hyperextended knee

Considerations

Your doctor will perform a physical examination to check for signs of PCL injury. This includes moving the knee joint in various ways.

Your doctor may also check for the presence of fluid in the knee joint. This test may show joint bleeding.

PCL injury may be seen using the following tests:

• Knee MRI
• Knee joint x-ray

Causes

The posterior cruciate ligament (PCL) is the strongest ligament in the knee. It extends from the top-rear surface of the tibia (bone between the knee and ankle) to the bottom-front surface of the femur (bone that extends from the pelvis to the knee).

The ligament prevents the knee joint from posterior instability. That means it prevents the tibia from moving too much and going behind the femur.

The PCL is usually injured by overextending the knee (hyperextension). This can happen if you land awkwardly after jumping. The PCL can also become injured from a direct blow to the flexed knee, such as smashing your knee in a car accident (called "dashboard knee") or falling hard on a bent knee.

Most PCL injuries occur with other ligament injuries and severe knee trauma. If you suspect PCL injury, it is important to be seen by a medical professional immediately.

Symptoms

• Knee swelling and tenderness in the space behind the knee (popliteal fossa)
• Knee joint instability
• Knee joint pain

First Aid

At first, a PCL injury is treated by:

• Splinting
• Applying ice to the area
• Elevating the joint (above the level of the heart)
• Taking nonsteroidal anti-inflammatory drugs (NSAIDs) for pain

Limit physical activity until the swelling is down, motion is normal, and the pain is gone. Physical therapy can help you regain joint and leg strength. If the injury happens suddenly (acute) or you have a high activity level, you may need surgery. This may be either knee arthroscopy or "open" surgical reconstruction.

Age has an effect on treatment. Younger patients are more likely to have problems without surgery, because chronic instability may lead to arthritis symptoms many years later. Which patients need surgery is controversial, because many people seem to do well without surgery. Injuries in which the bone is pulled off with the ligament, or multiple ligaments are injured need to be repaired with surgery.

PCL injuries are commonly associated with other ligament injuries or knee dislocation. It is important to have your knee examined for other injuries. Some of these injuries need to be treated urgently.

Call immediately for emergency medical assistance if

Call your health care provider if:

• You have symptoms of PCL injury
• You are being treated for PCL injury and you have greater instability in your knee
• Pain or swelling return after they went away
• Your injury does not appear to be getting better with time
• You re-injure your knee

A lot of PCL injuries are associated with other ligament injuries or severe knee trauma. You should be checked early for these other conditions.

Prevention

Use proper techniques when playing sports or exercising. Many cases are not preventable.

References

Miller RH III. Knee injuries. In: Canale ST, Beatty JH, eds. Campbell's Operative Orthopaedics. 11th ed. Philadelphia, Pa: Mosby Elsevier; 2007: chap 43.

Curtis C, Bienkowski P, Micheli LJ. Posterior cruciate ligament sprain. In: Frontera WR, Silver JK, eds. Essentials of Physical Medicine and Rehabilitation. 2nd ed. Philadelphia, Pa: Saunders Elsevier;2008:chap 67.