Posterior Cruciate Ligament (PCL) Injury

Written by Eric Metcalf, MPH, Kim Painter
Medically Reviewed by Zilpah Sheikh, MD on March 31, 2025
9 min read

A posterior cruciate ligament (PCL) injury is a tear or sprain of the PCL, a ligament that crosses the back of your knee. Ligaments are tough bands of tissue that connect bones.

The PCL is the largest and strongest of the four ligaments in each of your knees. It helps connect your thigh bone (femur) to your shin bone (tibia). It works with another ligament, the anterior cruciate ligament (ACL), to keep the bones from moving too far forward or backward. The two other ligaments in your knee, the medial collateral ligament (MCL) and lateral collateral ligament (LCL), control sideways motions.

It takes a lot of force to injure a PCL. So, the injuries that tear the PCL often also damage some of the other ligaments or cartilage in the knee. In some cases, the ligament can also break loose a piece of underlying bone.

How common is a PCL injury?

PCL injuries make up less than 20% of injuries to knee ligaments. One reason is that the PCL is thicker and stronger than the ACL, the most commonly injured knee ligament. The remaining ligament injuries involve the MCL or LCL.

PCL injuries are often due to a hard blow to a bent knee. Roughly half of such injuries result from motorcycle or car accidents, and half are the result of sports.

Your PCL might be damaged when:

  • Something forces your knee backward very quickly.
  • Your shin slams very hard into something, like your car’s dashboard.
  • Your knee twists or overextends in a sudden movement.
  • You fall or get tackled, landing on your bent knee with your foot pointing downward.

Sports are a common cause of PCL injury. These injuries are seen in:

  • Football
  • Soccer
  • Lacrosse
  • Hockey
  • Baseball
  • Gymnastics
  • Skiing

Most people don't feel or hear a "popping" sensation in the knee after a PCL injury. This is more common with an injury to the ACL.

After a PCL injury, people may often think of it as a minor knee problem and try to go on with their usual activities. However, symptoms that can develop include:

  • Mild to severe swelling 
  • Knee pain
  • A wobbly feeling in the knee
  • Trouble walking or putting weight on the knee
  • Trouble walking down stairs

If you have mild damage to the PCL and no other parts of your knee, you may not notice pain, swelling, or other problems at first. These symptoms may appear over time.

"You shouldn't ignore possible PCL problems, because continuing to walk or run on an unstable knee could lead to more severe or complicated injuries," says David Herzberg, a physical therapist and athletic trainer in Phoenix, Arizona, who is a spokesperson for the American Physical Therapy Association.

Over time, a PCL tear can also lead to osteoarthritis in the knee.

An injury to the PCL can cause mild to severe damage. Doctors often classify PCL injuries in these groups:

  • Grade I: The PCL has a partial tear, and the knee is a little loose, with the shin bone (tibia) moving a little further backward than it should.
  • Grade II: The ligament is completely torn, with tests showing an even looser knee, with more backward movement of the tibia, but no other injuries in the knee. 
  • Grade III: The ligament is completely torn, and you have injuries to other ligaments or knee structures, leaving the knee very unstable.

Some other doctors might use a four-tier system, classifying injuries as:

  • Grade I: A partial tear
  • Grade II: A partial tear with a looser knee
  • Grade III: A complete tear with no other injuries
  • Grade IV: A PCL injury along with another ligament tear in the knee 

PCL problems can be acute or chronic. Acute PCL problems are due to a sudden injury, while chronic PCL problems develop over time.

To diagnose a PCL injury, a doctor may take these steps:

History

Your doctor will ask what you were doing when the injury occurred, such as traveling in a car or playing a sport. They will also ask:

  • If your knee was bent, straight, or twisted when it was injured
  • How your knee felt after the injury
  • If you've had any symptoms since you were injured

Physical examination

In a common test for PCL injuries, you lie on your back with your knee bent. Your doctor then examines your knee and presses against your upper shin. Abnormal knee movement during this test suggests a PCL injury.

One sign of a torn PCL is that your knee may appear to droop backward in a way that isn't natural when your doctor straightens your leg.

You may also be checked with a device called an arthrometer. This presses against your leg to measure the ligament's tightness.

Your doctor may also ask you to walk. An abnormal walking motion may point to a PCL injury.

Imaging tests

An MRI is the main way to create images of a PCL tear. An MRI can find the exact location of a tear.

X-rays can also give information about a PCL injury. They can detect pieces of bone that may have broken loose from the injury.

With chronic PCL injuries, a bone scan may be needed to look for damage to the bones.

For the initial treatment of a PCL injury, the approach known as PRICE may be helpful. This includes:

  • Protecting the knee from further injury
  • Resting the knee
  • Icing the knee for short periods with cold packs
  • Compressing the knee gently, such as with an elastic bandage
  • Elevating the knee

You might also get some relief from over-the-counter pain relievers such as aspirin, ibuprofen, or naproxen. They help reduce pain and swelling.

The goal of treatment is to "restore full mobility, full strength, and full stabilization" to your knee and get you back as "quickly, safely, and effectively as possible" to your usual activities -- whether that's running marathons or walking around your house without pain, says Herzberg. Just resting, icing, compressing, and elevating the knee is unlikely to get those results, he says.

Some PCL injuries require surgery, but many milder sprains do not. Here's what you might expect from nonsurgical treatment.

Physical therapy

Once a doctor has diagnosed your PCL injury, you may be referred to a physical therapist. The therapist will focus at first on helping you do things like getting in and out of chairs, climbing stairs, and walking safely, in ways that protect your knee from further damage, Herzberg says.

Then, you'll work on strengthening muscles to support your knee, he says. That will include your front thigh muscles (quads), as well as the muscles in your buttocks (glutes) and the core muscles in your abdomen and back, he says.

The physical therapist will teach you exercises to do at home, too.

The number of sessions you'll need will depend on the severity of your injury and your goals for recovery. But typical nonsurgical patients will come two or three times a week for the first six weeks, then less often for a while after that, says Herzberg.  

If you see a physical therapist after surgery for a PCL injury, your surgeon will work with the therapist to set the pace of rehabilitation. But typical postsurgery patients come two to three times a week for up to three months, and less often for an added three to six months after that, Herzberg says.

Exercises for a PCL tear

Your physical therapist will teach you the safest, most effective way to do the exercises recommended for you. 

You might be prescribed exercises such as:

  • Quad sets. Sit or lie on the floor with your legs straight and a towel rolled under the injured knee. Tighten and hold your thigh muscles for a few seconds, release, and repeat several times.
  • Hip flexion. Lie on your back with your injured leg straight and the other leg bent. Tighten your thigh muscles, then lift the straight leg about a foot, hold, then lower slowly.
  • Static glutes. Lying down, you tighten your buttocks as hard as you can, without tightening your leg or back muscles. Hold for a few seconds, release, and repeat.

Knee braces 

Your doctor or therapist may suggest you wear a brace for a while to stabilize your knee, including during therapy sessions. Wearing your brace as recommended can help control your pain.

Crutches

You may need crutches to walk safely for a while. Your physical therapist can teach you how to use them on stairs and in other tricky situations, Herzberg says.

Does a PCL tear require surgery?

Most people don't need surgery to fix a torn PCL.

Your doctor is more likely to recommend it if you have: 

  • A severe PCL injury
  • Injuries involving more than one ligament
  • Symptoms that haven't improved enough after other treatments

Arthroscopic PCL surgery

In most cases, PCL repairs are done in an arthroscopic procedure. That means the surgeon inserts tools and a camera through small cuts around your knee. It's quicker to heal and results in less scarring than other knee surgeries.

During the surgery, your doctor won't stitch up your torn PCL. This doesn't heal well, and it may tear again. Instead, the surgeon will remove the old, torn ligament and replace it with new tissue.

The ligament may be replaced with:

  • Tissue from a deceased donor
  • A piece of tendon moved from somewhere else in the body, such as the back of the thigh or heel

Also, if a piece of bone is torn off, a surgeon may fasten the bone back into place using a screw.

Open PCL reconstruction

If your injury is severe or you are in an area without enough surgeons trained in arthroscopic procedures, your doctor may suggest open surgery. This requires a large incision in the knee. While the technique is different, the repairs to your ligament and other structures will be the same. You may have more pain with this type of surgery compared to the arthroscopic type. 

PCL surgery recovery time

After surgery, it may take you 6-12 months to regain full strength and movement in your knee. If you had a major tear with other knee injuries or had open reconstruction, expect your recovery to take longer.

While injuries to this ligament are somewhat uncommon, they can result in PCL damage that can have long-lasting effects. But there are some things you can do to make this less likely.

To lower your risk of a PCL injury, especially during sports:

  • Do dynamic stretches before physical activities. These are controlled movements, as opposed to static stretches, which you hold for a certain time.
  • Use proper walking and running techniques.
  • Stay alert and follow safety rules during sports.
  • Wear the right shoes for the surface you're playing on, such as a track or tennis court.

The posterior cruciate ligament is a ligament that supports the back of the knee. It plays a key role in keeping your knee stable. The PCL isn't as easily injured as an anterior cruciate ligament, but when it is sprained or torn, it can cause you a lot of discomfort and get in the way of your everyday activities. You may need to work with your doctor and a physical therapist to get your knee working well again.

Can you still walk with a PCL injury?

If the injury is severe, you might find walking difficult. In many cases, you'll feel pain and be unsteady on your feet. To stay safe, relieve pain, and avoid further injury, you may need to walk with a knee brace and crutches for a while.

How long do PCL injuries take to heal?

It depends on how severe the injury is. The mildest injuries might heal within a couple of weeks. But a severe injury that needs surgery might take six months or more after the surgery. During that time, you may still have some trouble walking or doing activities on your feet.

Is a PCL injury worse than an ACL injury?

Both kinds of injury can range from mild to severe. But ACL tear symptoms are often more severe, immediately causing very noticeable instability in the knee. PCL injuries can be less noticeable. Recovery from ACL surgery typically takes 6-12 months, about the same as with PCL surgery. But in some cases, it can take longer, up to 18 months.

Can a PCL heal on its own?

While a PCL might heal on its own, it's always best to get medical advice if you think you've injured a knee ligament. Returning to your exercise or sports routine without the right kind of rehab could turn a minor injury into a more severe problem, says Herzberg.