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

An LCL injury is an injury to the lateral collateral ligament, one of the key stabilising ligaments on the outside of the knee.

The LCL helps stop the knee from opening up too far on the outside. In simple terms, it helps protect the knee from side-to-side stress.

In technical terms, the LCL resists varus stress at the knee and contributes to posterolateral stability, especially during cutting, pivoting, landing and contact-based movements.

What is an LCL injury?

An LCL injury happens when the ligament is stretched, partially torn, or completely ruptured.

LCL injuries are usually described as:

Grade 1: Mild sprain

Grade 2: Partial tear

Grade 3: Complete rupture

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

How do people injure their LCL?

LCL injuries usually occur when a force pushes the knee outwards or places stress on the outside of the knee.

Common causes include:

• A blow to the inside of the knee

• Awkward landing or change of direction

• Twisting injury during sport

• Contact tackles or collisions

• Hyperextension of the knee

• Falls where the knee is forced sideways

• Higher-force trauma involving multiple knee structures

  
  

This type of injury can occur in sports such as rugby league, rugby union, AFL, soccer, basketball, skiing, martial arts and other sports involving contact, pivoting or sudden direction changes.

Common signs and symptoms of an LCL injury

Symptoms depend on the severity of the injury. A mild LCL sprain may feel like soreness on the outside of the knee, while a more significant tear may cause instability or difficulty returning to sport.

Common symptoms include:

• Pain on the outside of the knee

• Tenderness over the LCL

• Swelling or stiffness

• Pain with side-to-side movements

• Pain walking, running or changing direction

• Feeling unstable or like the knee may give way

• Difficulty returning to sport

• Bruising around the outside of the knee

• Reduced confidence loading the knee

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Clinically, an LCL injury may show pain or laxity with a varus stress test, tenderness along the lateral collateral ligament, reduced single-leg control, altered gait, and difficulty tolerating lateral or pivoting movements.

Physiotherapy treatment for LCL injuries

Physiotherapy for an LCL injury depends on the severity of the tear, symptoms, sport demands and whether other knee structures are involved.

Treatment usually focuses on:

• Reducing pain and swelling

• Protecting the healing ligament

• Restoring knee movement

• Improving walking mechanics

• Building quadriceps, hamstring, glute and calf strength

• Improving balance and lateral knee control

• Gradually returning to running, gym, work or sport

  
  

Early rehab may involve avoiding movements that place sideways stress on the knee, especially varus loading. As symptoms improve, exercises are progressed to rebuild strength, stability and confidence.

Mild to moderate LCL injuries can often be managed well with physiotherapy. Higher-grade tears, significant instability or suspected posterolateral corner involvement may require imaging or specialist review.

Differential diagnosis: what else could it be?

Not all outside knee pain is an LCL injury. Other conditions can present with similar symptoms, including:

• Meniscus tear

• ACL injury

• PCL injury

• Posterolateral corner injury

• Iliotibial band irritation

• Lateral hamstring tendon injury

• Biceps femoris tendinopathy

• Fibular head irritation

• Bone bruise or fracture

• Patellofemoral joint pain

• Knee osteoarthritis

• Peroneal nerve irritation

  
  

A proper physiotherapy assessment helps identify whether the LCL 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 outside knee pain, swelling, stiffness, instability or loss of confidence after a tackle, fall, twisting injury, awkward landing 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.