Posterolateral corner injury affects a complex group of ligaments, tendons and soft tissues on the outer-back portion of the knee. These structures help control twisting, external rotation, varus stress, and side-to-side stability. When the posterolateral corner (PLC) is injured, the knee can feel painful, unstable, and difficult to trust during walking, turning, running, or sport.

PLC injuries are less common than an ACL injury or MCL sprain, yet they often occur alongside these injuries. Early diagnosis matters because ongoing posterolateral instability may overload other structures such as the ACL, PCL, meniscus, or joint surfaces.

If knee pain or instability develops after a sporting injury, a physiotherapist may assess the knee and guide your next steps. For broader context, see our guides to knee ligament injuries, knee sports injuries, general knee pain and conditions, and the Acute Sports Injury Clinic for early assessment after a fresh injury.

What Is the Posterolateral Corner of the Knee?

The posterolateral corner sits on the outer-back side of the knee joint and contains several important stabilising structures. These commonly include the lateral collateral ligament (LCL), popliteus tendon, popliteofibular ligament, lateral capsule, and supporting tissues. Together, they help prevent excessive outward movement and abnormal external rotation of the lower leg.

Damage to this region can allow the tibia to rotate or shift more than it should. As a result, the knee may feel loose during cutting, pivoting, stepping downhill, or landing from a jump. PLC injuries are often missed early, particularly when swelling and pain from other ligament injuries dominate the picture.

Common Causes of Posterolateral Corner Injury

Most PLC injuries happen during high-force sporting or traumatic events. Common causes include:

• Direct contact to the inner knee that drives the joint outward
• Sudden twisting while the foot is planted
• Knee hyperextension injuries
• Awkward landing or cutting movements in sport
• Motor vehicle accidents or high-energy falls

Because PLC injuries often occur with ACL or PCL damage, clinicians usually assess the whole knee rather than focusing on one structure alone. For a broader overview of damaged support tissues, you can also read about a ligament tear.

Symptoms of Posterolateral Corner Injury

Symptoms vary depending on severity and whether other structures are involved. Many people report:

• Pain on the outer or back portion of the knee
• Swelling after injury
• A feeling that the knee may “give way”
• Difficulty walking on uneven ground or downhill
• Instability during pivoting, cutting, or turning
• Reduced confidence returning to sport

At times, the nearby peroneal nerve may also be irritated. This can contribute to numbness, tingling, weakness, or altered sensation into the lower leg or foot.

Diagnosis of Posterolateral Corner Injury

A physiotherapist or sports doctor usually begins with a detailed history and clinical examination. This may include ligament testing, assessment of rotational control, walking analysis, and comparison of side-to-side knee stability. They may also assess whether related structures such as the LCL, PCL, or meniscus are involved.

Imaging such as MRI may help confirm the diagnosis and identify associated injuries. A useful overview from NCBI StatPearls notes that lateral and posterolateral knee injuries warrant careful assessment because they can be easy to overlook and may contribute to persistent instability.

Posterolateral Corner Injury Treatment

Posterolateral corner injury treatment depends on how unstable the knee is, whether other ligaments are involved, and your activity goals. Mild injuries may improve with activity modification, bracing when appropriate, and progressive physiotherapy. In contrast, more severe injuries or combined ligament injuries may require surgery followed by structured rehabilitation.

Physiotherapy Rehabilitation

Mild to moderate PLC injuries may respond well to physiotherapy management. Rehabilitation often aims to:

• Reduce pain and swelling
• Restore knee range of motion
• Improve quadriceps, hamstring, calf, and gluteal strength
• Build balance, landing control, and neuromuscular stability
• Progress safely back to walking, running, and sport

A physiotherapist may also prescribe targeted knee exercises to rebuild strength and control around the joint. When ACL injury is also present, your rehab plan may overlap with principles used in ACL treatment and ACL injury prevention.

Surgical Management

Severe PLC injuries or injuries combined with ACL or PCL tears may require surgical reconstruction. Surgery aims to restore stability and reduce the risk of ongoing giving way, recurrent injury, or excessive stress on reconstructed cruciate ligaments.

After surgery, rehabilitation remains essential. Early stages usually focus on swelling control, movement restoration, and protected loading. Later phases progress into strength, dynamic control, and return-to-sport preparation.

People Also Ask: Can a Posterolateral Corner Injury Heal Without Surgery?

Some mild posterolateral corner injuries may recover without surgery when managed early with structured physiotherapy. However, complete tears or combined ligament injuries are less likely to regain full stability without surgical input. The best approach depends on the degree of laxity, your sport, and how stable the knee feels during daily activity.

Preventing Posterolateral Corner Injuries

Not every traumatic injury can be prevented, yet several factors may reduce risk or improve resilience:

• Strong hip, thigh, and calf muscles
• Good balance and single-leg control
• Progressive loading rather than sudden training spikes
• Better landing, cutting, and deceleration technique
• Completing rehabilitation fully after earlier knee injuries

These same principles are commonly used across many knee ligament rehabilitation programs and ACL prevention plans.

Frequently Asked Questions

Is a posterolateral corner injury serious?

It can be. Mild injuries may settle well with physiotherapy, but more severe PLC injuries may create lasting instability, especially when the ACL, PCL, or LCL are also injured.

How long does posterolateral corner injury recovery take?

Recovery time depends on injury severity, whether surgery is required, and how well the knee regains strength and stability. Mild injuries may improve over weeks to months, while post-surgical recovery is usually longer and progresses through staged rehabilitation.

Can you walk with a posterolateral corner injury?

Some people can still walk, especially with a milder injury. Even so, the knee may feel unstable, painful, or unreliable during turning, uneven ground, stairs, or downhill walking.

What to Do Next

If your knee feels unstable, swollen, or painful after a twisting or contact injury, early assessment may help identify ligament damage and guide the right rehabilitation plan. A physiotherapist can assess your knee stability, explain what structures may be involved, and help you progress safely back to work, exercise, and sport.

References

1. Figueroa F, Figueroa D, Calvo R, Vaisman A, Espregueira-Mendes J. Posterolateral corner knee injuries: a narrative review. EFORT Open Rev. 2021;6(8):676-685. View article
2. Maniar AR, Johnson DL. Posterolateral Corner of the Knee: An Update on Current Evaluation and Management Strategies. Curr Rev Musculoskelet Med. 2024. View article
3. Abu-Mukh A, Abu-Laban Y, Zein A, et al. Exploring the Posterolateral Corner of the Knee Joint: A Detailed Review of Recent Literature. Cureus. 2025;17(2):e80768. View article