What is a syndesmosis injury or high ankle sprain?

A syndesmosis injury, often called a "high ankle sprain," involves damage to the strong ligaments and membrane that stabilize the tibia and fibula bones just above the ankle joint.

Where exactly is the pain located with a syndesmosis injury?

Pain from a syndesmosis injury is typically located just above the ankle joint line, in the front and/or back of the lower leg, specifically in the space between the distal tibia and fibula bones.

How do syndesmosis injuries differ from typical ankle sprains?

Unlike common lateral ankle sprains that affect outer ankle ligaments, syndesmosis injuries involve the robust ligaments connecting the lower leg bones, are often more severe, and generally take longer to heal.

What movements worsen syndesmosis pain?

Pain from a syndesmosis injury is typically exacerbated by pointing the toes upwards (dorsiflexion), twisting the foot outwards (external rotation), and during weight-bearing activities, especially push-off or squatting.

How are syndesmosis injuries diagnosed?

Diagnosis involves clinical tests like the Squeeze Test and External Rotation Stress Test, direct palpation for tenderness, and imaging studies such as X-rays to check for widening and MRI to visualize ligament damage.

Where is the pain with syndesmosis?

Pain associated with a syndesmosis injury, often referred to as a "high ankle sprain," is typically localized to the anterior (front) and/or posterior (back) aspects of the lower leg, just above the ankle joint, specifically in the region where the tibia and fibula bones connect.

Understanding the Ankle Syndesmosis

The ankle syndesmosis is a crucial fibrous joint that stabilizes the distal tibia and fibula bones, forming the superior aspect of the ankle mortise. This complex is composed of several strong ligaments and a membrane:

Anterior Inferior Tibiofibular Ligament (AITFL): Located at the front of the ankle, connecting the tibia and fibula. This is the most commonly injured syndesmotic ligament.
Posterior Inferior Tibiofibular Ligament (PITFL): Located at the back of the ankle, connecting the tibia and fibula.
Interosseous Membrane (IOM): A strong, fibrous sheet running the entire length between the tibia and fibula.
Inferior Transverse Ligament (ITL): A deeper, posterior ligament that reinforces the PITFL.

The primary function of the syndesmosis is to maintain the integrity and proper spacing of the ankle mortise, preventing excessive widening or separation of the tibia and fibula during weight-bearing and movement.

The Nature of Syndesmosis Injuries (High Ankle Sprains)

Unlike common lateral ankle sprains that affect the ligaments on the outside of the ankle (e.g., anterior talofibular ligament), a syndesmosis injury involves damage to these specific ligaments connecting the lower leg bones. These injuries typically occur due to forceful mechanisms that cause external rotation and/or excessive dorsiflexion of the foot, often combined with an abduction force.

Common mechanisms include:

A planted foot being twisted externally (e.g., falling with the foot caught).
Direct impact to the outside of the ankle while the foot is dorsiflexed.
Falling or landing awkwardly after a jump.

Because of the robust nature of the syndesmotic ligaments and the significant forces required to injure them, high ankle sprains are often more severe, take longer to heal, and can result in more persistent pain and instability compared to lateral ankle sprains.

The Precise Location of Syndesmosis Pain

The pain from a syndesmosis injury is distinct from a typical ankle sprain and is critical for accurate diagnosis.

Anterior Ankle Pain: The most common location for pain is just above the ankle joint line, in the front of the ankle, specifically in the space between the distal tibia and fibula. This corresponds to the location of the AITFL. The pain is often described as a deep ache or sharp pain.
Posterior Ankle Pain: If the PITFL or ITL are involved, pain may also be felt at the back of the ankle, superior to the heel. This is less common as a primary pain source but can indicate more extensive injury.
Pain with Specific Movements: Pain is typically exacerbated by:
- Dorsiflexion: Pointing the toes upwards towards the shin.
- External Rotation of the Foot: Twisting the foot outwards.
- Weight-Bearing: Especially during push-off or single-leg stance.
- Squatting: Deep ankle dorsiflexion can reproduce pain.
Palpation Tenderness: Direct pressure over the syndesmotic ligaments, particularly the AITFL (anteriorly between the distal tibia and fibula), will elicit significant pain.
Referred Pain (Maisonneuve Fracture): In severe cases, a syndesmosis injury can be associated with a Maisonneuve fracture, which is a spiral fracture of the proximal fibula (near the knee). In such instances, pain may also be felt higher up the leg, near the knee, along with the ankle pain. This occurs when the external rotation force is transmitted up the interosseous membrane, causing the fibula to fracture proximally.

Differentiating Syndesmosis Pain from Other Ankle Injuries

Understanding the specific pain location is key to distinguishing a syndesmosis injury:

Lateral Ankle Sprain: Pain is usually centered around the lateral malleolus (outer ankle bone), affecting ligaments like the ATFL.
Medial Ankle Sprain: Pain is localized to the medial malleolus (inner ankle bone), involving the deltoid ligament complex.
Ankle Fractures: While fractures can occur anywhere, syndesmotic pain is specifically between the tibia and fibula, often without gross deformity unless associated with a significant fracture.

Diagnosis and Clinical Assessment

A thorough clinical examination is paramount for diagnosing a syndesmosis injury. Common physical tests include:

Squeeze Test: Squeezing the tibia and fibula together at mid-calf level typically elicits pain at the ankle syndesmosis.
External Rotation Stress Test (ERST): With the knee flexed to 90 degrees and the ankle dorsiflexed, the examiner applies an external rotation force to the foot. Pain at the syndesmosis confirms a positive test.
Palpation: Direct tenderness over the AITFL and the interosseous membrane.

Imaging studies like X-rays are used to rule out fractures and assess for widening of the syndesmosis. MRI is often the gold standard for visualizing ligamentous damage and confirming the diagnosis, especially in cases where the diagnosis is unclear or surgical intervention is being considered.

Management and Rehabilitation Considerations

Syndesmosis injuries often require a longer recovery period than typical ankle sprains, ranging from 6 weeks to several months, depending on severity. Management often involves:

Immobilization: In a boot or cast to protect the healing ligaments.
Non-Weight Bearing or Protected Weight Bearing: Initially, to prevent further stress on the injured joint.
Progressive Rehabilitation: Focusing on restoring range of motion, strength, balance (proprioception), and stability.
Surgical Intervention: May be necessary for severe injuries with significant instability or diastasis (widening) of the syndesmosis.

When to Seek Medical Attention

If you experience ankle pain, especially after a twisting injury, and the pain is located above the ankle joint, between the lower leg bones, or if you have difficulty bearing weight, it is crucial to seek prompt medical attention from a healthcare professional. Early and accurate diagnosis of a syndesmosis injury is vital for appropriate management and to prevent chronic pain and instability.

Pain from a syndesmosis injury, or "high ankle sprain," is typically localized to the front and/or back of the lower leg, just above the ankle joint, where the tibia and fibula connect.
This injury involves specific strong ligaments (AITFL, PITFL, IOM) that stabilize the ankle mortise, distinguishing it from more common lateral ankle sprains.
Syndesmosis injuries usually result from forceful external rotation and/or excessive dorsiflexion of the foot and are often more severe and take longer to heal.
Pain is characteristically worsened by specific movements like dorsiflexion, external rotation of the foot, and weight-bearing, and is tender upon direct palpation over the affected ligaments.
Diagnosis relies on clinical examination and specific tests, often confirmed with imaging like MRI, and management typically involves immobilization, protected weight-bearing, and progressive rehabilitation, with recovery potentially taking several months.

Syndesmosis Injury (High Ankle Sprain): Pain Location, Diagnosis, and Recovery