Posterior cruciate ligament (PCL) injury

Expert reviewer, Mr Damian McClelland, Trauma and Orthopaedic Consultant, and Clinical Director for Musculoskeletal Services at Bupa
Next review due October 2023

The posterior cruciate ligament (PCL) is one of the ligaments inside your knee – it connects your thigh bone (femur) to the back of your shin bone (tibia). A PCL injury is a partial or complete tear of the ligament or a stretched ligament.

About posterior cruciate ligament (PCL) injury

The PCL passes behind another ligament, the anterior cruciate ligament (ACL). The cruciate ligaments get their name from the fact they form a cross shape within the knee as they run in different directions from the thigh to the shin bone. Along with the other ligaments in your knee, your PCL keeps your knee stable and prevents your thigh and shin bones moving out of place.

When your knee ligaments are stretched but not torn, they’re called a sprain. Knee ligament injuries are given different grades depending on how severe they are. Usually, if you injure your PCL, you’ll have injuries to other parts of their knee as well, such as your medial collateral ligament or ACL.

Causes of posterior cruciate ligament (PCL) injury

It usually takes quite a powerful force to injure your posterior cruciate ligament (PCL). It’s often caused by a direct blow to the front of your knee when it’s bent, which extends it beyond the normal range of movement. This can happen if you:

• fall forward onto a bent knee
• have a car accident and hit your knees on the dashboard, which can tear the ligament
• are playing sport and have a direct blow to your knee from a collision with another player

Symptoms of a posterior cruciate ligament (PCL) injury

If you only injure your PCL, you may not have any, or only a few symptoms at first, and may not even notice that you’ve damaged it. You’ll probably still be able to walk normally afterwards. But you may get some pain behind your knee, especially when you kneel, and there might be some mild swelling. And you might not be able to move it as fully as before.

If your injury goes untreated for some time, your knee may start to feel sore, particularly at the front. You may also begin to find it uncomfortable going down an incline, while walking or running downhill for instance, or going down stairs. You may also have discomfort when you start to run, if you lift a heavy weight or if you walk longer distances.

It’s common to injure other ligaments, or other parts of your knee at the same time as your PCL. Together, these may cause general symptoms of pain and swelling in your knee.

Self-help for posterior cruciate ligament (PCL) injury

If you injure your knee, you should follow the POLICE procedure to manage any type of soft tissue injury to your knee. POLICE stands for protect, optimal loading, ice, compression and elevation.

Additionally, there are certain things you should avoid in the first three days after your injury so you don’t damage your knee further. These can be remembered as HARM, which stands for heat, alcohol, running and massage.

To find out more about POLICE and HARM, you can visit our page on what to do if you injure your knee.

If you’re having difficulty bearing weight on your knee, you may need to use crutches or wear a brace to support you for a while. Your doctor or physio will explain how long you’ll need to use these for.

Treatment of posterior cruciate ligament (PCL) injury

You’ll usually need to go to A&E with this kind of injury, where they’ll examine you and take some X-rays of your knee. They may then refer you to an acute knee clinic, which will organise any investigations and treatment you need.

The treatment you’re offered for a PCL injury will depend on several things. These include how severe the damage is, whether other parts of your knee are also injured, and how well you respond to treatment. The initial treatment is to control your pain and swelling using the POLICE and HARM self-help measures (see above). Further treatments to help you recover include physiotherapy, medicines and surgery.

You may see an orthopaedic surgeon (a doctor who specialises in bone surgery) or a sports medicine professional, such as a sports doctor or a physiotherapist. There are different treatments that your doctor or physiotherapist may suggest, and a lot that you can do yourself to help you recover.

Medicines

You can take over-the-counter painkillers, such as paracetamol or ibuprofen, to help relieve your pain. Your doctor may prescribe stronger painkillers if your knee is really painful. As well as easing your pain, non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen may help to reduce inflammation and swelling. Always read the patient information that comes with your medicine, and if you have questions, ask your pharmacist or GP for advice.

Physiotherapy

Your physiotherapist will carefully assess your knee then plan a programme of rehabilitation exercises to suit your individual needs. Exercises to strengthen your quadriceps (thigh) muscle are especially important after PCL injuries. Make sure you do the exercises as this is an important part of your recovery. The aim of physiotherapy is to help your knee recover its full range of movement and its strength and stability.

How long it takes to recover can vary – you may need physiotherapy for anything from two to 12 weeks initially. You might then need to continue doing exercises for up to year but ask your physio for advice.

Surgery

Most people do well with physiotherapy alone. But in some situations, surgery may be the best option to repair the injury to your PCL. This is most likely if:

• more than one ligament or tissue in your knee has been damaged
• your knee remains unstable or painful after physiotherapy

You should recover and be able to return to your normal activities, including sports, within four months to a year after your operation for a torn PCL. But check with your surgeon as this may vary. You’ll need to follow a course of physiotherapy after surgery, to build the strength up in your thigh muscles.

Ask your doctor about the pros and cons of surgery, and how it might help you.