What is a LCL injury?

A lateral collateral ligament (LCL) injury occurs when there is a tear to the lateral collateral ligament (the ligament on the outside of the knee that runs from the thighbone to the lower-leg bone). The LCL’s function is to keep the outer aspect of the knee joint stable.

An LCL injury could range from a spraining or straining to a partial or complete tear of the ligament. The LCL is one of the most commonly injured ligaments in the knee, and it is common to injure other ligaments when you injure the LCL.

Common related conditions
Knee Strain or Sprain Anterior Cruciate Ligament (ACL) Injury Medial Collateral Ligament (MCL) Injury Posterior Cruciate Ligament (PCL) Injury

Causes of lateral collateral ligament (LCL) injury

Direct force to the inside of the knee is the main cause of an LCL injury. This force puts pressure onto the outside of the knee and causes the LCL to tear or stretch. Other causes of a LCL injury:

  • Participating in high-impact force
  • Hyperextending the knee
  • Squatting with heavy objects
  • Landing awkwardly on the knee
  • Sudden change of direction on the knee

Risk factors for lateral collateral ligament (LCL) injury

  • Age — although anyone can suffer from an LCL injury, adults between the ages of 20-34 and 55-65 are more likely to sustain an LCL injury.
  • Sports — participating in sports such as basketball or football that require a quick change in direction while running can make you more likely to sustain an LCL injury.

Symptoms of lateral collateral ligament (LCL) injury

If you have a mild LCL injury, you may not experience any symptoms.

If you have a more severe LCL injury, you may experience pain, instability, swelling and stiffness.

Other symptoms of an LCL injury include:

  • Inability to walk
  • Decreased range of motion in the knee
  • Popping sound at the time of the injury
  • Swelling in the knee

Diagnosis of lateral collateral ligament (LCL) injury

An LCL injury is diagnosed in a physical examination by your primary care or orthopedic physician.

During the physical exam, your doctor may perform mobility and movement tests on your knee as well as ask you how you sustained the injury and medical history.

In many cases, the physician will order an x-ray or MRI to determine if other structures of the knee have been impacted by the injury.

Treatments for lateral collateral ligament (LCL) injury

The treatment protocol for an LCL injury depends on the severity of the injury. Mild sprains or tears may be treated with home therapy or physical therapy.

Home therapy may include:

  • Rest
  • Ice
  • Compression
  • Elevation (elevating the knee above the heart)
  • Anti-inflammatory medication
  • Splinting, bracing or using crutches to immobilize the knee

Treatments for more severe LCL injuries include:

  • Physical therapy and rehabilitation — you can begin strengthening exercises almost immediately after an LCL tear.
  • Platelet rich plasma (PRP) injection — PRP injections help speed the healing process by injecting growth factor platelets taken from your blood back into the injured site.

If the LCL injury is severe and causes instability in the knee, you may need surgical repair or reconstruction. If the injury occurred within a few weeks of your procedure and the ligament tear is from the upper or lower attachment, surgical repair can fix the injury.

If the injury occurred longer than three weeks prior or the ligament is torn in the middle, then a surgical reconstruction is needed to stabilize the knee. Your surgeon can use a tendon graft to perform a reconstruction.

Recovery from lateral collateral ligament (LCL) injury

When the range of motion in your knee returns, your physician and physical therapist may allow you to slowly return to your sport. You will need to gradually strengthen the knee and progressively build up your activity level before returning your normal activity level.

After recovering from an LCL injury, many doctors prescribe a knee brace that you can use while participating in your sport. The knee brace will keep the knee joint stable during strenuous activity.

Find an orthopedic doctor nearby

Mercy Health locations that can treat your LCL injury