Patient Basics: Posterior Cruciate Ligament (PCL) Injuries

A posterior cruciate ligament (PCL) injury is a stretch or tear of one of the main ligaments inside the knee. It often happens when something hits the front of a bent knee, such as the dashboard in a car crash or the ground in a hard fall. Most PCL tears heal well with a brace and exercise, without surgery.

Key points

• The PCL runs through the middle of the knee. It stops the shinbone from sliding backward under the thighbone.
• Common causes are car crashes, falls onto a bent knee and hard hits to the front of the shin in sports.
• Symptoms are often milder than with other knee injuries, so some people don’t know the ligament is torn.
• An exam and an MRI scan show how bad the tear is and whether anything else in the knee is hurt.
• Most people recover with physical therapy that builds up the thigh muscles. Surgery is mainly for complete tears with other damage.

What the PCL does

Ligaments are tough bands of tissue that hold bones together. The knee has four main ones. Two of them, the cruciate ligaments, cross each other in the center of the joint like an X. “Cruciate” means crossed. The anterior cruciate ligament (ACL) sits in front, and the posterior cruciate ligament sits behind it.

The PCL joins the thighbone (femur) to the back of the shinbone (tibia). It keeps the shinbone from being pushed too far back. It is thicker and stronger than the ACL, so it tears less often.

Doctors grade the damage from 1 to 3:

• Grade 1: a mild sprain with a small tear. The knee stays steady.
• Grade 2: a larger partial tear. The knee feels a bit loose.
• Grade 3: a full tear. The knee is unstable, and other ligaments are often hurt as well.

What causes a PCL injury

• Car crashes. A bent knee slams into the dashboard and drives the shinbone backward. Doctors call this a dashboard injury.
• Falling onto a bent knee with the foot pointed down, so the top of the shin takes the impact.
• Contact sports. A tackle or a hard hit to the front of the shin in football, soccer or rugby.
• Bending the knee backward too far (hyperextension), or a hard twist. These tend to tear other ligaments too.
• A knee dislocation, where the thighbone and shinbone are forced out of line. This tears several ligaments at once and is an emergency.

Symptoms

• Pain in the knee, often toward the back
• Swelling that builds over a few hours
• Stiffness and trouble bending the knee all the way
• Limping or trouble putting weight on the leg
• A feeling that the knee is loose or might give way, mostly when going down stairs or walking downhill
• A bruise or scrape on the front of the shin from the blow

Many people with a torn PCL can still walk, and the pain may ease within days. A tear can be missed for that reason. Weeks later, the knee may ache, feel weak or hurt around the kneecap.

How doctors check your knee

• Exam. The doctor compares both knees. With you lying on your back and your knees bent, they look for the top of the shinbone sagging backward. They also push gently on the shin to see how far it moves (the posterior drawer test). They check the other ligaments, the nerves and the pulses in your foot.
• X-rays look for broken bones. Sometimes the ligament pulls a small chip of bone off where it attaches.
• MRI. This scan shows the ligament itself, plus the cartilage, the meniscus (the cushions in the knee) and the other ligaments.

How a PCL injury is treated

Without surgery

Most grade 1 and 2 tears, and many grade 3 tears that happen alone, are treated this way:

• Rest, ice and raising the leg for the first few days to bring down swelling
• Pain relief with acetaminophen, or an anti-inflammatory such as ibuprofen or naproxen if these are fine for you
• Crutches for a short time if walking hurts
• A knee brace. Some PCL braces have a pad behind the calf that holds the shinbone forward while the ligament heals.
• Physical therapy. The focus is on the quadriceps, the large muscles on the front of the thigh. Strong quadriceps help hold the shinbone in place. Exercises also bring back bending, balance and control.

Surgery

Surgery is usually advised when:

• Several ligaments are torn, or the knee was dislocated
• The ligament pulled off a piece of bone that can be fixed back in place with a screw
• The knee keeps giving way even after months of therapy

In PCL reconstruction, the surgeon replaces the torn ligament with a graft. This is a piece of tendon from your own leg or from a donor. The operation is usually done through small cuts with a thin camera (arthroscopy).

Recovery and getting back to sport

A grade 1 or 2 tear usually allows a return to sport in about 4 to 12 weeks. After reconstruction, recovery often takes 9 to 12 months. Before you go back, a therapist can test your strength, balance and how steady the knee feels.

A knee that stays loose for years can wear down the cartilage and lead to arthritis, mostly behind the kneecap and on the inner side of the knee. Keeping your thigh muscles strong for the long term helps protect the joint.

Lowering your risk

• Wear a seat belt on every trip.
• Build leg strength and balance, and warm up before sports.
• Learn safe tackling and falling skills, and wear the right gear for your sport.

When to see a doctor

• Knee pain or swelling after a fall, a hit or a crash
• Trouble putting weight on the leg
• A knee that feels loose or gives way
• Pain that isn’t improving after a week

Get emergency care if the knee looks bent or out of place, or your foot turns cold, pale, numb or weak after a knee injury. A knee dislocation can damage the main artery behind the knee, and this needs treatment within hours.

Common questions about PCL injuries

What does PCL mean in medical terms?

PCL stands for posterior cruciate ligament. “Posterior” means toward the back, and “cruciate” means crossed, because it crosses the ACL inside the knee. You may see PCL on a scan report or in your doctor’s notes after a knee injury.

Can a torn PCL heal on its own?

Often, yes. The PCL has a better blood supply than the ACL, and many partial tears heal with a brace and physical therapy. The ligament may heal a little longer and looser than before, so strong thigh muscles matter. Complete tears with other damage are less likely to heal well alone.

Can you walk with a torn PCL?

Many people can, especially with a partial tear. Walking may feel stiff or unsteady at first, and stairs or slopes can be harder. Being able to walk doesn’t mean the injury is minor, so have a doctor check any knee that swells or feels loose after an injury.

Is a PCL injury worse than an ACL injury?

Usually not. PCL tears happen less often, cause milder symptoms and more often heal without surgery. ACL tears are more common in sports with sudden stops and turns, and athletes usually need surgery to go back to those sports. Either one can be serious when other ligaments tear too.

Questions to ask your doctor

• What grade is my PCL tear?
• Are other parts of my knee hurt?
• Do I need a brace, and for how long?
• When can I go back to work or sports?
• What signs would mean I need surgery?

Learn more

• Knee injuries and disorders (MedlinePlus, U.S. National Library of Medicine)

This guide is general information and doesn’t replace advice from your own doctor. Last updated October 2026.