PCL Injury

What is a PCL injury?

The posterior cruciate ligament (PCL) sits at the back of the knee, where it stops the shin bone (tibia) from sliding backwards beneath the thigh bone. It is thicker and stronger than the ACL, which is why isolated PCL tears are relatively uncommon.

A PCL injury usually follows a forceful blow to the front of a bent knee — classically striking the dashboard in a car accident, or falling onto the front of the knee in sport. Tears range from a mild sprain to a complete rupture, often as part of a wider knee injury.

Signs and symptoms

PCL symptoms are often more subtle than an ACL tear, and the injury can be missed at first. Common signs include:

• checkMild to moderate swelling that develops over the first day.
• checkA vague sense of instability particularly going down stairs or slopes.
• checkAching at the back of the knee and discomfort when kneeling.
• checkStiffness and difficulty pushing off when walking quickly.

Causes & risk factors

• A direct blow to the front of a bent knee (dashboard injury).
• Falling onto the knee with the foot pointed down.
• Hyperextension or a severe twist, often with other ligament damage.
• Contact and collision sports such as football and rugby.

How it is diagnosed

The posterior drawer test assesses how far the tibia sags backwards, which grades the injury. An MRI confirms the tear and — crucially — checks for the associated ligament and meniscus injuries that change the treatment plan. X-rays exclude any bony avulsion.

Treatment options

Unlike the ACL, most isolated PCL injuries heal well without surgery, because the ligament has a good blood supply and the surrounding structures help it recover.

Recovery & outlook

With a structured programme, most patients with an isolated PCL injury return to full activity within three to six months and report a stable, comfortable knee. Where surgery is needed for a combined injury, recovery is longer and is staged carefully alongside the other repairs.