The “Overlooked” Ankle Sprain: What Is a Syndesmotic Injury?

High ankle sprain showing syndesmotic injury with pain highlighted above the ankle joint

A syndesmotic injury—also called a high ankle sprain—is a more serious type of ankle sprain that affects the ligaments between the two lower leg bones, the tibia and fibula. The syndesmosis is the group of ligaments that connect the distal tibia and the distal fibula at the ankle joint, and it is vital because it provides lateral stabilization of the ankle joint.

These injuries are harder to detect than typical ankle sprains and can lead to long-term ankle instability if not diagnosed and treated properly.

How Is a Syndesmotic Injury Different From a Regular Ankle Sprain?

Most ankle sprains affect the ligaments on the outside of the ankle. A syndesmotic injury involves the ligaments higher up, near where the tibia and fibula meet just above the ankle joint. This type of injury is often caused by twisting or rotating the ankle during sports or falls.

What Are the Symptoms of a Syndesmotic Injury?

  • Pain above the ankle
  • Difficulty walking or bearing weight
  • Swelling and bruising (sometimes mild)
  • Pain with rotation or certain movements

Because the pain may not be severe at first, the injury can go unnoticed or be mistaken for a simple sprain.

Why Are Syndesmotic Injury Symptoms Easy to Miss?

The signs of a syndesmotic injury can be incredibly subtle. Standard X-rays may not always show the damage. If the injury is paired with a fracture, doctors may focus on the broken bone and miss the ligament injury entirely.

That’s why a specialist’s evaluation is so important. With a syndesmotic injury, even a subtle injury can lead to ankle instability. If left untreated, chronic, subtle ankle instability will lead to significant ankle arthritis over time.

Orthopaedic specialist reviewing ankle X-rays to diagnose a syndesmotic injury

How Are These Injuries Diagnosed?

An orthopaedic specialist will examine the ankle and may order additional specific imaging. Dr. Sophia Davis notes that the “go-to” approach when evaluating syndesmotic sprains is to get bilateral weight-bearing mortise views.

Because there is a wide range of what constitutes a “normal” syndesmotic measurement, specialists will compare the injured ankle side-by-side with your healthy limb. If there is subtle widening on one side compared to the other, the physician knows there is syndesmotic instability that may need treatment. Ultrasound or MRI may also be used to detect instability between the tibia and fibula.

What Are the Treatment Options?

  • Mild injuries: Rest, bracing, and physical therapy.
  • Moderate to severe injuries: Surgery may be needed to stabilize the joint, especially if a fracture is involved.

Surgeons often use screws or flexible devices to hold the bones together while the ligaments heal. Follow-up care is essential to avoid long-term widening or instability in the ankle.

When Should You See a Doctor?

If your ankle pain doesn’t improve within a few days, feels unstable, or you notice pain higher up on the leg, it’s time to see a foot and ankle specialist. Early diagnosis leads to better outcomes and prevents the onset of long-term arthritis.

Two women checking ankle pain symptoms that may indicate a syndesmotic injury

Key Takeaways: Syndesmotic Injuries

  • A syndesmotic injury is a high ankle sprain affecting the ligaments between the tibia and fibula.
  • It provides vital lateral stabilization for the ankle joint.
  • It often requires advanced, comparative side-by-side imaging to detect subtle widening.
  • Treatment depends on severity, ranging from bracing to surgery.
  • Untreated injuries and chronic instability can cause significant ankle arthritis over time.
  • See a specialist if your pain lingers or feels different from what you’d expect with a typical ankle sprain.

Frequently Asked Questions (FAQ)

A syndesmotic injury, also called a high ankle sprain, occurs when the ligaments between the tibia and fibula (the syndesmosis) are stretched or torn—usually from a twisting motion.

Pain above the ankle, especially with twisting or weight-bearing, can signal a high ankle sprain. Unlike regular sprains, the pain may feel deeper and less localized.

Because normal measurements vary, specialists often use bilateral weight-bearing mortise X-rays. This allows them to compare your injured ankle to your uninjured one to look for subtle widening of the joint.

Not always. Mild injuries may heal with bracing and physical therapy. Severe or unstable injuries—especially when paired with a fracture—often require surgical repair.

Some can, but untreated injuries risk long-term ankle instability. Chronic, subtle ankle instability can lead to significant ankle arthritis over time. It’s important to be evaluated by an orthopaedic specialist.

Recovery depends on severity. Mild cases may resolve in a few weeks, while post-surgical recovery can take several months with physical therapy.

Think your ankle sprain might be more than it seems?

Request an appointment with a foot and ankle specialist at Orlando Orthopaedic Center today and get back on your feet.

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