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Posterior Cruciate Ligament (PCL) Injury

The posterior cruciate ligament (PCL) is a ligament in the back of your knee. A PCL injury occurs when you damage or tear your PCL.

A PCL injury can cause knee pain, swelling, and difficulty walking. Doctors treat PCL injuries with medicine, lifestyle changes, physical therapy, and surgery.

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What Is a Posterior Cruciate Ligament (PCL) Injury?

Your posterior cruciate ligament (PCL) is a ligament that connects your upper and lower leg and helps control movement in your knee joint. (Ligaments are tissue fibers that connect one bone to another.)

A sprained or torn PCL can cause knee swelling and pain and can impact your ability to walk and move your knee.

The PCL is the strongest and largest of the four ligaments in your knee, so it takes a lot of force to injure it. PCL injuries usually happen when you twist, fall on, or hit your knee hard. Most people injure their PCL during car accidents or while they’re playing sports.

If your PCL injury is mild to moderate, it may heal in a few days or weeks with rest and medicine. If your PCL injury is severe, you might need physical therapy or surgery to repair it.

How common is a PCL injury?

PCL injuries aren’t common. Less than 20% of all knee ligament injuries involve the posterior cruciate ligament.

Your PCL is twice as strong as your anterior cruciate ligament (ACL), which is another ligament that supports your knee. That’s why you’re more likely to get an ACL injury than a PCL injury.

What are the types of PCL injuries?

Doctors rate PCL injuries based on how severe they are. There are four categories:

  • Grade I. You have a partial sprain or tear in your PCL.
  • Grade II. You have a partial sprain or tear in your PCL, and your PCL feels loose.
  • Grade III. Your PCL's completely torn, and your knee is unstable.
  • Grade IV. Your knee is unstable, and your PCL and another knee ligament (like your ACL) also are injured.

What causes a PCL injury?

You won't get a PCL injury from a minor accident, like twisting your knee while stepping off a curb. It takes a strong force on your knee to cause a PCL injury, such as:

  • A direct hit to the front of your knee.
  • Severely pulling, twisting, or overextending your knee.

About half of PCL injuries are the result of car or motorcycle accidents. The other half happen while playing sports.

You’re most likely to experience a PCL injury during contact sports like:

  • Football.
  • Hockey.
  • Lacrosse.
  • Soccer.

You can also injure your PCL while skiing or doing gymnastics.

What are posterior cruciate ligament (PCL) injury risk factors and complications? 

PCL injury risk factors 

You can get a PCL injury at any age, but you’re most likely to have one in your twenties. Men are twice as likely as women to have a PCL injury.

Playing contact sports puts you at a higher risk for PCL injuries.

Complications of a PCL injury

Most of the time, PCL injuries don’t cause lasting problems. But left untreated, PCL injuries can lead to chronic knee pain or trouble walking or moving your knee.

If you have a severe PCL injury, you may have difficulty walking even after treatment. This is most likely to happen if you tear your PCL and another ligament at the same time.

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What Are the Signs and Symptoms of a PCL Injury?

Signs of a PCL injury include:

  • Mild to severe knee pain.
  • Knee stiffness and swelling.
  • Limping when you walk.
  • Being unable to walk.
  • Feeling like your knee’s unstable or might give out.

When should I see a doctor about my PCL injury symptoms?

If you’ve been in an accident and your knee is swollen or painful, see a doctor.

Call a doctor immediately or go to the emergency room if:

  • Your knee, leg, or foot feels cold or numb.
  • Your knee, leg, or foot turns a different color.
  • You have severe pain or swelling in your knee.
  • You have trouble walking after a knee or leg injury.

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How Do You Diagnose a PCL Injury? 

If your doctor suspects you may have a PCL injury, they'll ask you about your medical history, including:

  • When and how you injured your knee.
  • If you’ve had other knee injuries in the past.

Your doctor also will examine your knee and leg to see how they look, feel, and move. They'll also run tests.

Tests to diagnose posterior cruciate ligament (PCL) injury

If your doctor thinks you've injured your PCL, they’ll recommend tests, including:

  • X-ray. Although x-rays don’t diagnose PCL injuries, they help doctors see if you have a fracture or another knee problem.
  • Knee MRI. The main way doctors diagnose PCL injuries, MRI shows tissue changes or tears in your PCL.

PCL injury outlook

If you have a minor PCL injury, your knee may feel better in a few days or weeks. If you have a big PCL tear and need surgery, it can take six months to a year to completely recover. During that time, you may have trouble walking or doing other activities where you’re on your feet.

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How Do You Treat a PCL Injury?

The goal of PCL treatment is to ease knee pain and swelling while your PCL heals. Doctors treat PCL injuries with medicine, lifestyle changes, physical therapy, and surgery.

Lifestyle changes to treat a PCL injury

Doctors often recommend RICE treatment right after a PCL injury. This method includes:

  • Resting your knee.
  • Icing your knee.
  • Compressing your knee with an elastic bandage or wrap.
  • Elevating your leg above your heart level.

Your doctor also may recommend you use:  

  • A knee brace to keep your knee stable.
  • Crutches to help you walk without putting weight on your knee.

Learn how to use the RICE method for treating injuries from UPMC HealthBeat.

Medication to treat a PCL injury

Doctors treat PCL injuries using nonsteroidal anti-inflammatory drugs (NSAIDs), which include ibuprofen (Advil) and naproxen (Aleve). NSAIDs help ease knee pain and swelling.

Physical therapy for a PCL injury

If your PCL injury makes it hard for you to walk or move your knee, your doctor may recommend physical therapy.

A physical therapist will show you exercises that help you strengthen and move your knee, and strengthen the leg muscles that support your knee.

Surgery for posterior cruciate ligament (PCL) injury

You may need surgery to repair a torn PCL, especially if you also injured other ligaments, like your ACL. Sometimes doctors also recommend surgery if other treatments for an injured PCL haven't been effective.

The main surgery for PCL injuries is knee arthroscopy.

What happens during surgery for PCL injuries?

With knee arthroscopy, your doctor will make small cuts in your knee area. Then, they'll reconstruct your PCL using a tissue graft from another part of your body. Sewing a torn PCL back together usually isn’t enough to heal it.

It will likely take several months for your PCL to heal after surgery. If you had a major PCL tear or your doctor had to repair other ligaments, too, recovery can take up to a year.

Complications from surgery for PCL injuries aren’t common. But you could experience:

  • Bleeding.
  • Blood clots.
  • Swelling in your knee.
  • Stiffness in your knee.
  • Infection.

How effective is treatment for a PCL injury?

With treatment, you can expect to recover from your PCL injury. After treatment, you may need to wear a knee brace when you're exercising or doing sports.

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