An ankle syndesmosis injury is a common cause of pain at the front (anterior) of your ankle. This injury is also referred to as a high ankle sprain as it affects the ligaments above the ankle joint. Whilst an ankle syndesmosis injury is less common than your traditional ankle sprain, the associated symptoms are often more disabling and the recovery period longer.
Your lower leg consists of two bones, the tibia, which is the large shin bone, and the fibula, a smaller bone running down the outside of the leg. Just above the ankle joint these two bones are held together by a ligament called the distal tibiofibular ligament. Between the two bones is a fibrous connective tissue that assists in holding them together as well. This fibrous tissue is called the syndesmosis.
The role of the syndesmosis is to provide stability and support during rotational movements and loading of the ankle joint. During weightbearing activities there will be a small amount of widening between the tibia and fibula. The syndesmosis prevents these two bones from widening too far.
Ankle syndesmosis injuries often occur when the foot is planted on the ground and the leg is twisted inwards (internally rotated), or if the foot itself is forcefully twisted outwards (externally rotated). This mechanism of injury results in an over-stretching and, potentially, tearing of the distal tibiofibular ligament and syndesmosis. This type of injury is more common in the sporting population, especially sports such as football and snow skiing.
Ankle syndesmosis injuries are often a result of trauma. Associated symptoms include:
- Pain across the front of the ankle joint that is aggravated particularly with external rotation of the foot
- Pain and difficulty with walking and other weight-bearing activities
- Bruising and swelling across the front of the ankle which may extend down the outside (lateral) part of the ankle as well
The severity of symptoms will largely depend on the severity of the injury.
Ligament injuries can be classified based on the severity of tearing of fibres.
- Over-stretching of the ligament with no tearing of fibres.
- Recovery can be expected to be approximately 6 weeks.
- Return to high level sporting activity however may take longer due to the physical demands.
- Partial tearing of the ligament and can be further classified as unstable or stable.
- Recovery is between 6-12 weeks
- If the ankle is classified as unstable, surgery may be required.
- Complete rupture of the ligament.
- This type of injury will require surgery and recovery time will be between 3-6 months.
The first step in diagnosis of an ankle syndesmosis injury is to complete a detailed history and clinical examination. Information gathered in your history may increase the suspicion of an ankle syndesmosis injury based on the mechanism of injury (e.g., foot external rotation) and aggravating activities (e.g., the inability to walk / weight-bear).
The clinical examination will test the integrity of the distal tibiofibular ligament and syndesmosis, and the physical capacity of the ankle itself. Tests may include ligament laxity testing, range of motion, palpation, strength, and functional testing.
If suspected you may be referred for further investigations such as a weight-bearing X-ray, CT scan, or MRI. These investigations will help confirm the diagnosis of an ankle syndesmosis injury and determine if there is an associated fracture or not. If referred for an x-ray it must be weight-bearing as this type of x-ray will show if there is any separation between the tibia and fibula.
Treatment will always be personalised and largely depend on the severity of the injury. Basic treatment principles, though, include:
- Protect and allow for adequate healing of the ligament and ankle joint
- Restore ankle range of motion
- Restore ankle strength
- Restore ankle proprioception and balance
- Restore functional and sporting capacity
- Pain and swelling management
Specific treatment options include:
Rest (active rest), ice, compression, and elevation are important treatment strategies in the acute stage and as rehabilitation progresses. The RICE protocol assists in pain and swelling management, as well as protection of injured tissues. As your rehabilitation progresses you will begin to load your ankle joint more. This may result in an increase in pain and swelling after activities such as walking or your home exercise program. The RICE protocol can help to manage this, and the swelling and pain immediately associated with the injury.
Taping and Bracing
Taping and bracing can help to increase the stability of the ankle joint and decrease the load placed upon it after injury. This will help to protect it from further damage, as well as assist in managing pain by decreasing the load placed upon injured tissues. In severe cases, if there is an associated fracture and after surgery, a CAM boot and crutches may be required for further immobilisation and protection.
Manual therapy is particularly important in assisting to restore ankle range of motion. Techniques include soft tissue therapy (e.g., massage) and joint mobilisation. By restoring range of motion, daily activities, such as walking and running, will become easier due to an increase in function and decrease in pain.
Load Management / Exercise Prescription
Depending upon the severity of symptoms and stage of rehabilitation will depend upon how much load your ankle can tolerate. Load through your ankle will come in the form of exercise prescription. Appropriate load management is important to avoid any aggravating or further injury. Exercise prescription is important in assisting to restore strength, proprioception, and balance. Overall this will enhance ankle stability which will help to restore your functional and sporting capacity. Exercises will be progressed as your capacity increases.
For unstable ankle syndesmosis injuries (Grades 2 and 3), surgery will be required to restore ankle stability. This is usually achieved by inserting pins to hold the tibia and fibula together to prevent widening of these bones during weight-bearing activities. The type of surgery will need to be discussed with your specialist and will be determined by your specific type of injury and severity. A referral to a specialist will need to be arranged by your doctor.
Surgery will not preclude the need for physiotherapy, though. In fact, physiotherapy treatment can be even more important to restore mobility and strength after an operation.