Glossary
Posterior cruciate ligament (PCL)
Quick answer
The posterior cruciate ligament (PCL) is a thick ligament in the centre of the knee that crosses behind the ACL. It stops the shin bone sliding backwards under the thigh bone and is the knee's main stabiliser against backward force, explains Dr. Pablo Gelber, knee surgeon at Aman Hospital in Doha.
What it is
The PCL runs from the inner side of the notch in the femur down and back to the rear of the tibial plateau, crossing the ACL to form an X. It is wider and stronger than the ACL and has a better blood supply, which is one reason many PCL injuries can heal with careful treatment.
Why it matters for patients
The PCL is usually injured by a force pushing the shin backwards: a dashboard injury in a car accident, a fall onto a bent knee with the foot pointed, or a tackle in contact sport. Symptoms can be milder than an ACL tear, with aching at the back of the knee, discomfort on stairs or slopes, and a vague sense of instability, so it is sometimes missed.
Isolated PCL tears are often treated without surgery, using a brace that supports the back of the tibia and a focused quadriceps programme. When the PCL is torn together with other ligaments, as in a knee dislocation, reconstruction is usually advised.
How it is examined
With the knee bent, a surgeon looks for the shin sagging backwards and performs the posterior drawer test. MRI shows the tear, and stress X-rays can measure how far the tibia moves backwards.
Frequently asked questions
Is a PCL tear less serious than an ACL tear?
Isolated PCL tears often do well without surgery, but they still need proper diagnosis because combined injuries, especially with the posterolateral corner, need different treatment.
Why does my knee hurt kneeling after a PCL injury?
Kneeling and deep bending load the back of the knee where the PCL works hardest. Many patients feel this discomfort during the early months of recovery.
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