PCL Injuries: What They Are, How They Happen, and How Physiotherapy Can Help

A PCL injury is an injury to the posterior cruciate ligament, one of the main stabilising ligaments inside the knee.

The PCL helps stop the shin bone from sliding too far backwards under the thigh bone. In simple terms, it helps stop the knee from “shifting backwards.”

In technical terms, the PCL resists posterior translation of the tibia on the femur and helps with overall knee stability, especially when the knee is bent.

What is a PCL injury?

A PCL injury happens when the ligament is stretched, partially torn, or completely ruptured.

PCL injuries are usually described as:

Grade 1: Mild sprain

Grade 2: Partial tear

Grade 3: Complete rupture

PCL injuries can happen on their own, but they can also occur with other knee injuries, including meniscus tears, cartilage injuries, MCL injuries, LCL injuries or posterolateral corner injuries.

How do people injure their PCL?

PCL injuries usually occur when a force pushes the shin bone backwards while the knee is bent.

Common causes include:

• A direct blow to the front of the shin or knee

• Falling onto a bent knee

• Sporting tackles or collisions

• Car accidents, especially dashboard-type injuries

• Hyperflexion or forceful bending of the knee

• Higher-force trauma involving multiple knee structures

  
  

This type of injury is often seen in contact sports such as rugby league, rugby union, soccer, AFL, martial arts and other collision-based sports.

Common signs and symptoms of a PCL injury

PCL injuries can sometimes be less obvious than ACL injuries. Some people can still walk after the injury, but the knee may feel sore, swollen, unstable or just “not right.”

Common symptoms include:

• Pain at the front or back of the knee

• Swelling after injury

• Stiffness or reduced movement

• Difficulty walking normally

• Pain going downstairs

• Pain kneeling

• Weakness or loss of confidence

• Feeling like the knee is loose or unstable

• Difficulty running, changing direction or returning to sport

  
  

Clinically, a PCL injury may show increased posterior tibial translation, a positive posterior drawer test, a posterior sag sign, reduced quadriceps control and difficulty tolerating loaded knee flexion.

Physiotherapy treatment for PCL injuries

Physiotherapy for a PCL injury depends on the severity of the injury, symptoms, sport demands and whether other structures are involved.

Treatment usually focuses on:

• Reducing pain and swelling

• Protecting the healing ligament

• Restoring knee movement

• Improving walking mechanics

• Building quadriceps strength

• Gradually improving balance and knee control

• Returning safely to running, gym, work or sport

  
  

Early rehab often avoids deep knee bending and heavy hamstring loading, as these can place extra strain on the PCL. As symptoms improve, exercises are progressed to rebuild strength, stability and confidence.

Many isolated PCL injuries can be managed without surgery, but higher-grade injuries, ongoing instability or combined ligament injuries may need imaging or specialist review.

Differential diagnosis: what else could it be?

Not all knee pain after injury is a PCL injury. Other conditions can present with similar symptoms, including:

• ACL injury

• Meniscus tear

• MCL or LCL injury

• Posterolateral corner injury

• Patellofemoral joint pain

• Bone bruise or fracture

• Hamstring or calf injury

• Baker’s cyst

• Knee osteoarthritis

• Cartilage injury

  
  

A proper physiotherapy assessment helps identify whether the PCL is involved, whether another structure is causing symptoms, and what level of rehabilitation is required.

When should you see a physiotherapist?

You should consider seeing a physiotherapist if you have knee pain, swelling, stiffness, instability or loss of confidence after a fall, tackle, collision or direct blow to the knee.

Early assessment can help determine the severity of the injury and guide the right recovery plan.

At Urban Physiotherapy, we assess the full knee picture, including injury mechanism, ligament stability, strength, movement quality and return-to-sport demands.