PCL Injury

PCL injury, or posterior cruciate ligament injury, can cause pain deep inside or behind the knee. It may also cause swelling, heaviness, reduced power, or a feeling that the knee does not fully trust itself during downhill walking, stairs, deceleration, kneeling, or sport.

The posterior cruciate ligament sits deep inside the knee. It helps stop the shinbone from moving too far backwards under the thighbone. Many isolated PCL injuries improve with structured rehabilitation, but the plan should match the injury grade, swelling, stability, sport demands, and any other knee damage.

For broader context, start with our knee pain guide, the sports knee injuries page, and the knee ligament injury hub.

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What Is a PCL Injury?

A PCL injury is a sprain or tear of the posterior cruciate ligament. This ligament runs from the thighbone to the back of the shinbone. It mainly controls backwards movement of the shinbone and also helps with knee rotation.

Because the PCL helps control deep knee stability, an injury can affect walking downhill, stairs, squats, kneeling, running, landing, and change of direction.

Quick Guide: When a PCL Injury May Need Assessment

pain at the back or deep centre of the knee after a fall, tackle, or direct blow
swelling, stiffness, or reduced knee bend
difficulty walking downhill, using stairs, squatting, or kneeling
a heavy or unstable feeling during running or deceleration
concern about a combined injury, such as ACL, meniscus, or posterolateral corner damage

How Do PCL Injuries Happen?

PCL injuries usually need a clear force. Common mechanisms include a fall onto a bent knee, a direct blow to the front of the shin, a motor vehicle dashboard injury, or contact during sport. They can also occur with hyperextension or awkward landing.

PCL injuries can happen in field and court sports, especially when contact, falls, landing, or fast direction change are involved. They may also occur with other knee injuries, including an ACL injury, meniscus tear, or posterolateral corner injury.

What Are the Symptoms of a PCL Injury?

PCL symptoms can be less dramatic than some other knee ligament injuries. Some people keep walking after the injury. However, walking does not prove the injury is minor.

deep knee ache or pain behind the knee
swelling or stiffness after the injury
reduced power when pushing off, running, or climbing stairs
difficulty trusting the knee downhill or during deceleration
pain with kneeling, squatting, or loaded knee bend
a loose or unstable feeling, especially in higher-grade tears

Can You Walk on a PCL Injury?

Yes, many people can walk after a PCL injury, especially with a mild sprain. Even so, walking does not rule out a moderate or complete tear. If the knee swells, feels unstable, or loses confidence during stairs, slopes, or sport, assessment helps clarify the safest next step.

How Is a PCL Tear Diagnosed?

A physiotherapist starts with your injury story. The mechanism matters because a direct blow to the shin, fall onto a bent knee, or high-force sports collision can point towards PCL involvement.

Your assessment may include swelling checks, range of motion, strength testing, balance, walking, squatting, and knee stability tests. Posterior drawer and posterior sag tests help assess PCL laxity. Your clinician may also check for related injuries around the knee.

General medical information from the American Academy of Orthopaedic Surgeons also explains how PCL injuries affect knee stability and why treatment depends on severity and related damage: posterior cruciate ligament injuries.

Do You Need an MRI for a PCL Injury?

MRI may help confirm a PCL tear and check for meniscus, cartilage, bone bruise, ACL, MCL, LCL, or posterolateral corner involvement. Imaging is more likely when the injury was high force, swelling is marked, instability persists, or return-to-sport decisions need more detail.

PCL Injury Grades

PCL injuries are commonly graded by laxity, symptoms, and function. The grade helps guide early protection, bracing, rehabilitation pace, and whether surgical review is worth considering.

Grade	What It Means	Common Plan
Grade I	Mild sprain with minimal looseness.	Relative rest, swelling control, strength, and graded return.
Grade II	Partial tear with moderate laxity and symptoms.	Structured rehab, possible bracing, and clear progress testing.
Grade III	Complete tear with marked laxity, often with other injuries.	Specialist review may be needed, especially if function remains unstable.

How Is a PCL Injury Treated?

PCL injury treatment depends on the grade, symptoms, swelling, related injuries, sport demands, work needs, and goals. Many isolated PCL injuries improve with progressive physiotherapy. Combined ligament injuries need closer planning and may need orthopaedic review.

For broader knee care options, see knee treatment. If surgery is involved, our post-operative physiotherapy page explains how staged rehabilitation supports recovery after an operation.

PCL injury rehab using single-leg control exercise for knee stability — Rehab builds control before harder sport tasks.

PCL Rehab: What Usually Comes First?

Early PCL rehab usually aims to settle swelling, protect healing tissue, restore comfortable movement, and rebuild quadriceps strength. Your physiotherapist may initially limit exercises that increase backwards shear on the shinbone.

Early Phase: Settle and Protect

reduce swelling and pain
restore comfortable knee movement
protect the knee from high-load posterior shear
improve walking confidence
begin safe quadriceps and hip strength work

Build Phase: Strength and Control

progress quadriceps, calf, hip, and trunk strength
restore single-leg balance and control
build step, squat, and lunge tolerance where appropriate
monitor swelling and next-day response
progress running only when criteria are met

Sport Phase: Running, Landing, and Direction Change

graded running and deceleration
landing mechanics and hop progressions
change-of-direction drills
sport-specific loading under fatigue
return-to-training and return-to-play testing

Does a PCL Tear Need a Brace?

Some PCL injuries benefit from a brace, especially early in higher-grade injuries. A brace may help reduce posterior sag and support confidence while strength and control improve. Bracing decisions should match the injury grade, symptoms, sport demands, and medical advice.

Does a PCL Tear Need Surgery?

Surgery is not routine for every PCL injury. It may be considered when a complete tear causes ongoing functional instability, when there is significant posterior laxity, when the injury involves multiple ligaments, or when high-demand work or sport needs more stability.

For isolated PCL injuries, a structured rehabilitation pathway is often trialled first when the knee is stable enough and there are no major associated injuries. For combined injuries, the decision is more complex and should include clinical findings, imaging, goals, and specialist advice.

Decision point: If your knee feels stable in daily life but unreliable with sport, the next step is usually not guesswork. Strength testing, swelling response, control tests, and graded exposure help decide whether rehab is progressing safely.

When Can You Return to Sport After a PCL Injury?

Return to sport varies. A mild isolated sprain may settle faster than a complete tear or combined injury. A safer return relies on milestones rather than a calendar date alone.

Your physiotherapist may assess swelling, range, strength symmetry, single-leg control, running tolerance, hop quality, deceleration, cutting, confidence, and sport-specific exposure. Athletes may also benefit from broader knee injury prevention principles, because landing, strength, and change-of-direction control matter across many ligament injuries.

What Other Knee Injuries Can Feel Similar?

PCL injury can overlap with other knee problems. Inner knee pain may point towards an MCL tear. Outer knee pain or side-loading instability may point towards an LCL injury. Locking, catching, or joint-line pain may suggest meniscus involvement.

PCL Injury FAQs

Can you walk on a PCL injury?

Many people can walk after a PCL injury, especially with a mild sprain. However, walking does not rule out a significant tear. Assessment helps confirm the grade, related injuries, and safe early loading plan.

How do you know if you tore your PCL or ACL?

PCL injuries often cause posterior knee ache, heaviness, downhill difficulty, or a sense of posterior instability. ACL injuries more often involve a giving-way episode with pivoting and rapid swelling. A clinician uses specific tests and may recommend MRI to confirm the pattern.

Do PCL tears heal without surgery?

Many isolated PCL injuries improve with progressive rehabilitation, especially low to moderate grades. Surgery may be considered for complete tears with ongoing functional instability, major posterior laxity, or combined ligament injury.

How long does PCL rehab take?

Timeframes vary. Mild injuries may improve over weeks. Higher-grade injuries or combined injuries may take months. Your plan should progress by symptoms, swelling, strength, control, and sport demands rather than time alone.

What exercises should you avoid early after a PCL injury?

Early on, you may need to limit exercises that drive the shinbone backwards under load. Your physiotherapist will guide which movements to avoid and when to reintroduce them based on the injury grade and your response.

When should you get a PCL injury checked?

Arrange assessment if swelling, posterior knee pain, instability, locking, or reduced confidence lasts more than a few days. Seek urgent medical care after major trauma, deformity, severe swelling, inability to weight-bear, or symptoms that suggest a vascular or nerve problem.

PCL injury return to running after knee ligament rehabilitation — Return to running should follow strength, control, and confidence.

What to Do Next

If your knee is swollen, painful, unstable, or hard to trust after a fall, collision, or direct blow, reduce sport and book an assessment. A physiotherapist can help identify the likely injury pattern, guide early loading, and advise whether imaging or medical review is needed.

If you are returning to sport, ask for a staged plan that includes strength, control, running, landing, and change-of-direction criteria. This reduces guesswork and helps you make safer training decisions.