What is a posterior cruciate ligament (PCL) injury?
A PCL injury is a sprain or tear of the posterior cruciate ligament (PCL). The PCL is a band of tissue that crosses inside the centre of the knee joint. It connects your thigh bone to the bone of your lower leg. The PCL keeps your knee stable when it moves forward or backward.
A direct blow to the knee can injure your PCL. For example, the PCL can be injured in a car crash when your bent knee hits the dashboard. You can also hurt your PCL during sports, such as football, soccer, or skiing. Or you can hurt it while doing other activities if you fall on your bent knee with your foot or toes bent downward or if the front of your knee is hit.
A PCL injury can also happen if you stretch or straighten your knee beyond its normal limits (hyperextend the knee).
What are the symptoms?
An injury to your PCL may cause:
- Swelling, pain, tenderness, and stiffness. Several hours after the injury, your pain may get worse. And it might be harder to move your knee.
- An unstable feeling, like the knee may give out.
How is a PCL injury diagnosed?
The doctor will examine you and ask questions about your past health. He or she will also ask how you injured your knee and about your symptoms at the time you injured it.
Your doctor will carefully examine your knee and leg. He or she will look and feel to see if there is swelling and may gently push on certain places to find spots that are most tender. Then your doctor will move your knee and leg in certain ways to help check for stability. He or she will also look at the rest of your leg to make sure that blood is flowing, the leg works well, and there are no other injuries above or below the knee.
How is it treated?
Most PCL injuries can be treated at home with:
- Rest and protecting your knee.
- Ice or a cold pack.
- Wrapping your knee with an elastic bandage (compression).
- Propping up (elevating) your knee.
- Anti-inflammatory medicine.
Your doctor may suggest that you use crutches to limit how much weight you put on your leg. He or she may also suggest that you wear a brace that protects and supports the knee but allows for some movement.
You may need to be less active for a while. But doing gentle stretching and range-of-motion exercises as advised by your doctor will help you heal.
Your treatment will depend on how severe your injury is and whether other parts of your knee are injured.
- Mild or grade 1 and moderate or grade 2 injuries may only need home treatment along with using crutches for a short time and wearing a hinged knee brace. Many people are able to be active again after about 4 to 6 months.
- Severe or grade 3 injuries may require using crutches and wearing a hinged knee brace. In some cases, surgery may be needed. Many people are able to be active again after about 9 months.
Your doctor may recommend physiotherapy to increase range of motion and strengthen your muscles.
How can you care for yourself at home?
- Put ice or a cold pack on your knee for 10 to 20 minutes at a time. Try to do this every 1 to 2 hours (when you're awake) for the first 3 days after your injury or until the swelling goes down. Put a thin cloth between the ice and your skin.
- Prop up your leg on a pillow when you ice it or anytime you sit or lie down. Do this for about 3 days after your injury. Try to keep your knee above the level of your heart. This will help reduce swelling.
- Take anti-inflammatory medicines to reduce pain and swelling. These include ibuprofen (Advil, Motrin) and naproxen (Aleve). Be safe with medicines. Read and follow all instructions on the label.
- Follow instructions about how much weight you can put on your leg and how to walk with crutches, if your doctor recommends them.
- Wear a brace, if your doctor recommends it, to protect and support your knee while it heals. Wear it as directed.
- Do stretches or strength exercises as your doctor suggests.
When should you call your doctor or nurse call line?
Call 911 anytime you think you may need emergency care. For example, call if:
- You have symptoms of a blood clot in your lung (called a pulmonary embolism). These may include:
- Sudden chest pain.
- Trouble breathing.
- Coughing up blood.
Call your doctor or nurse call line now or seek immediate medical care if:
- You have increased or severe pain.
- Your foot is cool or pale or changes colour.
- You have tingling, weakness, or numbness in your toes.
- You cannot move your toes.
- You have signs of a blood clot, such as:
- Pain in your calf, back of the knee, thigh, or groin.
- Redness and swelling in your leg or groin.
Watch closely for changes in your health, and be sure to contact your doctor or nurse call line if:
- You do not get better as expected.
Other Works Consulted
- Adib F, et al. (2015). Posterior cruciate ligament sprain. In WR Frontera, JK Silver, TD Rizzo Jr., eds., Essentials of Physical Medicine and Rehabilitation, 3rd ed., pp. 394–398. Philadelphia: Saunders.
- McMahon PJ, et al. (2014). Sports medicine. In HB Skinner, PJ McMahon, eds., Current Diagnosis and Treatment in Orthopedics, 5th ed., pp. 88–155. New York: McGraw-Hill.
- Petrigliano FA, et al. (2015). Posterior cruciate ligament injuries. In MD Miller, SR Thompson, eds., DeLee and Drez's Orthopaedic Sports Medicine: Principles and Practice, 4th ed., vol. 2, pp. 1164–1182. Philadelphia: Saunders.
Current as of: March 2, 2020
Author: Healthwise Staff
Adam Husney MD - Family Medicine
Kathleen Romito MD - Family Medicine
Patrick J. McMahon MD - Orthopedic Surgery