A syndesmosis injury, often called a high ankle sprain, affects the joint that holds the two lower leg bones together just above the ankle. Unlike a common ankle sprain that involves the ligaments on the outside of the ankle, a syndesmosis injury damages the ligaments that bind the tibia and fibula, and it tends to take longer to recover. These injuries range from a mild sprain through to more serious tears that need surgery.
What Is a Syndesmosis Injury?
The syndesmosis is the joint where the two bones of the lower leg, the tibia and fibula, meet just above the ankle. It is held together by strong ligaments that keep the two bones in the correct position as you walk, run and change direction. A syndesmosis injury happens when these ligaments are overstretched or torn, usually through a forceful twisting of the foot and ankle. It has become a well-known injury in sport, and some codes have adjusted their rules to reduce the risk.
Why It’s Called a High Ankle Sprain
Because the syndesmosis sits above the level of the true ankle joint, a syndesmosis injury is commonly called a high ankle sprain. This sets it apart from the far more common ankle sprain, which involves the ligaments on the outside of the ankle. The distinction matters, because a high ankle sprain usually behaves differently and takes longer to settle than a standard ankle sprain, even when the early pain seems similar.
The Three Syndesmosis Ligaments
Three ligaments make up the syndesmosis. At the front is the anterior inferior tibiofibular ligament, between the two bones is the interosseous ligament, and at the back is the posterior inferior tibiofibular ligament. Together, this ligament complex holds the tibia and fibula snugly together. In a syndesmosis injury, any combination of these ligaments can be affected, and which ones are involved helps determine how serious the injury is.
Grades of Syndesmosis Injury
Syndesmosis injuries are graded by which structures are torn and whether the ankle remains stable. A grade one is a sprain of the front ligament without instability. A grade two involves more ligament damage and is divided further: a stable grade is managed without surgery, while an unstable grade, confirmed on weight-bearing X-rays, usually requires surgical stabilisation. A grade three is a complete tear of all three ligaments with widening of the joint, which also needs surgery. Getting the grade right is essential, because it determines whether the injury is managed with rehabilitation alone or with an operation first.
When Is Surgery Needed?
Not every syndesmosis injury needs surgery. Stable injuries are typically managed conservatively with a period of protected loading and structured rehabilitation. Where the joint is unstable, a surgeon may recommend a procedure to hold the tibia and fibula in alignment while the ligaments heal, sometimes using a flexible fixation known as a tightrope technique. The decision rests with an orthopaedic surgeon, and imaging plays a key role in guiding it. Whatever the pathway, post-surgical rehabilitation is central to a good outcome.
Rehabilitation: The Return to Performance Framework
Because a syndesmosis injury is almost always sport-related, rehabilitation usually follows a staged return to performance framework. The first phase focuses on protecting the healing ligaments while maintaining range of motion and the condition of the surrounding muscles. The second builds ankle range, strength, coordination and early fitness. The third reintroduces sport-specific skills, speed and agility in a controlled setting, and the final phase replicates the chaotic demands of competition before an athlete is cleared to return to play. Progressing through these phases in order, rather than by the calendar, is what protects against re-injury. Our return to sport conditioning is built around exactly this kind of staged progression.
Common Questions
How Long Does a Syndesmosis Injury Take to Recover?
Recovery is generally longer than for a standard ankle sprain. A mild, stable injury may take several weeks, while a higher-grade injury or one that needs surgery can take a few months before a full return to sport. Your physiotherapist and surgeon can give you a clearer timeframe once the grade is known.
Is a High Ankle Sprain Worse Than a Normal Ankle Sprain?
It is usually more involved. A high ankle sprain affects the ligaments that bind the leg bones together, which take longer to heal and can affect stability. This is why it often needs a more careful and staged rehabilitation than a common outside-of-the-ankle sprain.
Do All Syndesmosis Injuries Need Surgery?
No. Stable injuries are commonly managed without surgery through protected loading and rehabilitation. Surgery is generally reserved for injuries where the joint is unstable or the ligaments are completely torn, as confirmed on imaging.
When Can I Return to Sport After a Syndesmosis Injury?
Return to sport depends on passing each stage of rehabilitation rather than reaching a set date. An athlete is usually cleared once they can handle full-speed running, agility and the demands of competition without symptoms. Rushing this stage is a common cause of setbacks.
How BeFit Can Help
At BeFit Training Physiotherapy, our physiotherapists assess and rehabilitate syndesmosis injuries and other ankle injuries at both our Edgecliff and Coogee clinics. We work alongside your surgeon where needed, and build a staged return to performance plan suited to your sport and goals. Every initial consultation runs for forty-five minutes, one-on-one, with a thorough assessment and a clear explanation of what we find. Whether your injury came from top-level competition or weekend sport, we support active people across Sydney’s Eastern Suburbs, and no referral is required to book.
Book an appointment at BeFit Training Physiotherapy — no referral needed.
Edgecliff: (02) 9327 7749 | Coogee: (02) 7205 2805 | befittrainingphysio.com/book-now
Related Services
Learn more about our shin, ankle and foot injury physiotherapy, joint sprain treatment and return to sport conditioning in Sydney.
References
Williams GN, et al. Syndesmotic ankle sprains in athletes. Am J Sports Med. 2007.
van Dijk CN, et al. Classification and diagnosis of acute isolated syndesmotic injuries. Knee Surg Sports Traumatol Arthrosc. 2016.
Vopat ML, et al. Return to sport following syndesmosis injury: a systematic review. Sports Health. 2021.
Australian Physiotherapy Association. Clinical guidelines. physiotherapy.asn.au.
