High Ankle Sprain (Syndesmosis Ligament Injury)

If you have sprained or otherwise injured your ankle recently, you could be at risk of having an injured syndesmosis ligament as well, also known as a high ankle sprain. This type of injury can occur when the ankle is forcefully twisted outwards, or if the leg is twisted inwards while the foot is held stable.

Syndesmosis Ligament Injury Anatomy

The syndesmosis is the ligament that connects the tibia and the fibula, which are the two bones that make up the lower leg. The tibia is more commonly known as the shin bone, and it supports most of the body’s weight. The fibula is smaller and located on the outside of the leg. 

These bones work together to stabilize the ankle joint, and they themselves are stabilized by the syndesmosis ligament. Injuries to the syndesmosis ligament could cause the ankle to become unstable.  

Syndesmosis Ligament Injury Causes

A high ankle sprain is most likely to occur when the foot is stable, and the ankle is twisted outwards. Excessive dorsiflexion (when the foot is pushed upwards towards the shin) while placing large amounts of weight on the ankle can also cause a high ankle sprain. This occurs frequently in football tackles.

Syndesmosis Ligament Injury Symptoms

Syndesmosis ligament injuries often occur in conjunction with other ankle injuries, and symptoms can often meld with those of ankle sprains or fractures. However, some of the symptoms that characterize syndesmosis injuries include:

  • Pain above the ankle, which typically increases with outward rotation of the foot
  • Calf pain
  • Inability to place weight on the leg

The severity of your symptoms depends entirely on the severity of your high ankle sprain, and if a bone fracture has occurred in conjunction with the injury of the syndesmosis ligament. Some symptoms may only appear when stress is placed on the ankle, while others will be continuous. 

Syndesmosis Ligament Injury Diagnosis

Anyone who has recently sprained or fractured their ankle should be examined for a possible syndesmosis ligament injury, or high ankle sprain.

The majority of the time, your doctor will need to have X-rays done of your foot and ankle to determine if a syndesmosis ligament injury has occurred. Normal X-rays will not typically show a syndesmosis ligament injury, so a special type of X-ray called a stress X-ray will be necessary. 

In a stress X-ray, the X-ray examiner will apply force to the ankle during the X-ray. If your doctor sees that the syndesmosis ligament shifts under pressure, then it is likely a syndesmosis ligament injury has occurred. CT scans and MRIs are also sometimes used to confirm the diagnosis of a syndesmosis ligament injury.

Your doctor will be looking for a gap in the joint where the tibia and fibula are connected. A gap of less than 2mm is considered to be “stable”, while a gap of larger than 2mm is at risk of becoming “unstable”.

Syndesmosis Ligament Injury Treatment

Your tibia and fibula support your entire weight and the force of your body while you are walking or running. Damaging the ligaments which stabilize these bones will likely require you to use crutches or a walking boot.

Other treatments depend if your ankle has become unstable or not. In syndesmosis ligament injuries where the ankle has become unstable, surgery is usually necessary.

With surgical treatment, metal screws are passed through the fibula and into the tibia. This will hold your bones, and the syndesmosis ligament, in their correct positions while the ligament heals. The screws will usually be removed about 3-4 months later. Physical therapy will be necessary afterward, as well as a gradual return to vigorous physical activity.

Physical therapy following surgery will entail:

  • Preventing further injury by teaching you proper ways to move your foot and leg so as not to irritate the site of the injury
  • Regaining full range of motion by strengthening the ankle and calf muscles
  • Restoring joint flexibility 
  • Sport-specific skills, if you are an athlete

Your doctor and physical therapist will work together to come up with a treatment that is safe and works for you. Placing too much stress on the site of the injury too early can injure the ligament again, and cause problems like ankle arthritis down the road. 

Nonsurgical treatments like rest, anti-inflammatory medications, and eventually physical therapy are used to treat syndesmosis ligament injuries in which the ankle remains stable.

Syndesmosis Ligament Injury Recovery

What we think of as a common ankle sprain is what is known as a “low ankle sprain”. These types of sprains heal quickly with rest and proper pain management. High ankle sprains heal more slowly, especially if it is an unstable injury. 

Stable injuries can be treated with crutches or a walking boot and will require a recovery period of about six weeks. Unstable injuries that are treated with surgery will require anywhere from 3 to 6 months to fully recover from, though this can vary, depending on your specific injury. 

At SPORT, we will identify the source of your pain and then utilize state-of-the-art therapeutic techniques that focus on restoring your range of motion.

Depending on the specific condition and its severity, these treatment options may include physical therapy, over-the-counter anti-inflammatory medication, slings and supports, cortisone shots, or foot or ankle surgery.

If you have an acute or chronic foot or ankle injury that needs medical attention, call SPORT at (469) 200-2832 to arrange a consultation or you can request one online. Hurt today? We can arrange a same-day urgent care visit to ensure you get fast, effective relief.


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