Syndesmosis injury, also known as a high ankle injury, is more common than thought. Generally, these injuries occur with other injuries, such as ankle sprains and fractures. Often, if left untreated, high ankle sprains can lead to chronic pain and poor function. So, how do we diagnose a syndesmosis injury, and what do we do about it?
What is Syndesmosis?
The high ankle joint, also called the syndesmosis, connects the two long bones of the lower leg, the tibia and fibula. It lies just above the ankle joint and provides stability to the ankle and lower leg. Three strong ligaments maintain this joint. A tear of one or more of these ligaments can lead to excessive movement of these bones and ankle instability.
What Causes a Syndesmosis Injury?
Sydesmosis injuries primarily occur during contact sports such as football, rugby, ice hockey and lacrosse. They account for 11-17% of total ankle sprains.
Generally, we suspect a high ankle or syndesmosis injury when the foot twists outwards relative to the lower leg. This injury, also called an eversion ankle sprain, occurs when the foot is turned outward or planted, and the lower portion of the leg is turned inward. However, other injuries can also cause a high ankle sprain, such as the common inversion ankle injury.
Diagnosis of Syndesmosis Injury
A syndesmosis injury often occurs together with other ankle injuries. So, a correct diagnosis can sometimes be tricky. However, in general, doctors look for the following signs:
- A more severe ankle sprain with increased swelling, often extending above the ankle
- Pain above the ankle joint
- Difficulty with weight bearing
Doctors’ assessments reveal tenderness in the high ankle joint, and stress tests for the high ankle are often painful. For example, these injuries typically yield a positive external rotation test, in which the ankle is dorsiflexed and externally rotated. Other tests include the squeeze test of the mid-calf and the fibular translation test. In recent studies, only the external rotation test has been shown to predict time to return to sport.
Weight-bearing X-rays help rule out fractures or separations of the bones of the lower leg (also called diastasis). However, they often miss a milder syndesmosis sprain. MRI helps determine damage to the three ligaments of the high ankle. Increasingly, doctors are using ultrasound to detect damage to the high ankle. Using dynamic views, physicians can often observe ligament tears and joint widening with ankle movement.
How to test for Syndesmosis Injury?
We use clinical tests to determine whether a patient has suffered a syndesmosis sprain. Generally, there is tenderness over the anterior aspect of the high ankle ligament. Squeezing the calf—the squeeze test—produces pain in the high ankle. Rotating the foot and ankle in external rotation—the external rotation test—also reproduces pain in the high ankle.
High vs. low ankle sprain
Generally, high ankle sprains are more severe than low ankle sprains. Clues to whether a person has sustained a high ankle sprain include the injury description (typically, these sprains involve twisting of the ankle outward, with substantial swelling extending up to the lower part of the calf and difficulty with weight-bearing). Additionally, other signs suggestive of a high ankle sprain include tenderness above the ankle joint and pain with outward foot rotation or calf squeeze.
Can you play with a syndesmosis injury?
Generally, we think that high ankle sprains are more severe than simple low ankle sprains. Therefore, sports participation after high ankle sprains is more challenging than after lateral ligament sprains. Additionally, these ankle sprains take longer to heal because the ligaments connecting the ankle to the leg are subjected to greater forces, which require more time for healing.
How to Heal a High Ankle or Syndesmosis Injury
Overall treatment for high ankle sprains depends on the severity of the sprain.
For mild cases involving one ligament, we recommend a walking boot for a few weeks, followed by physiotherapy. After treatment in a boot, supervised physiotherapy will help restore the ankle to full function.
In more severe injuries that lead to joint widening, surgical fixation of the joint with a screw or tightrope will stabilise it. Failure to detect these unstable high ankle sprains can lead to chronic pain, joint swelling, and early arthritis.
In moderate cases, where more than one high ankle ligament is torn, both conservative and surgical methods can be used. We recommend consulting a foot and ankle surgeon to determine the most appropriate course of treatment.
How Long for a Syndesmosis Injury to Heal?
Generally, a high ankle sprain takes twice as long as a typical ankle sprain to heal. For milder, higher ankle sprains, return to sport may take 6-12 weeks. Recovery can take up to 4 months, and may be longer in more severe ankle sprains that require surgery. So, you must make a speedy diagnosis to get on the right track to recovery.
Can a cortisone injection help speed up recovery from a high ankle sprain?
Yes. A high ankle sprain may be slow to resolve due to pain or swelling; a corticosteroid injection directed to the ankle may be beneficial.
A cortisone shot for the ankle will reduce pain and swelling and accelerate the return to running and sports. We should use ultrasound guidance for the cortisone injection to improve accuracy and effectiveness.
Recent studies suggest that PRP injections can accelerate healing. One study found that elite athletes treated with PRP injections had less residual pain upon return to activity.
Final word from Sportdoctorlondon about a high ankle sprain
High ankle sprains are generally more common than we think after twisting an ankle. The key is early detection and assessment of the severity of the injury. A plain X-ray at A&E does not rule out a high ankle injury. You must see a sports doctor for an accurate diagnosis and treatment plan.
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