A high ankle sprain is an injury to the ligaments that connect your two lower leg bones (the tibia and fibula) just above the ankle joint. Unlike a common ankle sprain, which damages ligaments on the outside of the ankle, a high ankle sprain disrupts the joint that holds the bottom of your shinbones together. This makes it a more serious injury that typically takes nearly twice as long to heal as a standard sprain.
What Makes It Different From a Regular Sprain
Your ankle is held together by several groups of ligaments. The ones most people sprain are on the outer side of the ankle, where the foot rolls inward during a misstep. A high ankle sprain targets a completely different structure called the syndesmosis, a joint formed by four ligaments that bind the tibia and fibula together just above the ankle. These include the front and back tibiofibular ligaments, the transverse ligament, and the interosseous ligament, which is a thickened extension of the membrane running between your two shinbones.
This distinction matters because the syndesmosis is responsible for keeping your ankle “mortise” stable. The mortise is the bony socket that cradles the talus, the bone that sits on top of your foot. When the syndesmosis is torn, that socket widens, and the talus can shift around inside it. That instability is what makes high ankle sprains harder to recover from and more damaging if missed.
How High Ankle Sprains Happen
The most common mechanism is external rotation of the foot, meaning your foot gets twisted outward while your leg stays planted. A tackler falling across the outside of a football player’s planted leg is the classic scenario. The talus, forced to rotate laterally, pushes the fibula away from the tibia, tearing the syndesmosis ligaments in the process.
The second major cause is extreme dorsiflexion, where the foot is forced upward toward the shin beyond its normal range. Because the front of the talus is wider than the back, pushing the ankle into deep dorsiflexion wedges the malleoli apart. This is common in running and jumping sports when an athlete’s foot is planted and they fall or are pushed forward. Both mechanisms can occur together, and the combination is especially destructive to the syndesmosis.
Symptoms to Watch For
High ankle sprains feel different from typical ankle sprains in a few important ways. The most telling sign is pain that radiates up the leg from the ankle rather than staying concentrated around the outer ankle bone. This pain gets significantly worse with weight-bearing or when you pivot on your foot.
Surprisingly, high ankle sprains usually don’t produce much visible swelling or bruising. A regular lateral ankle sprain often causes dramatic swelling that spreads into the foot, so the relatively mild appearance of a high ankle sprain can be misleading. People sometimes assume the injury is minor because it doesn’t look bad, walk on it too soon, and delay proper treatment. Another hallmark is an inability to hop on the injured leg, which clinicians use as a quick screening tool.
How It Gets Diagnosed
Diagnosing a high ankle sprain can be tricky because no single physical exam test catches every case. Clinicians typically use a combination of tests. Pressing directly on the syndesmosis ligaments (palpation) is the most sensitive screening method, picking up about 92% of syndesmosis injuries. A stress test that involves pushing the foot into dorsiflexion while rotating it outward catches about 71% of cases. A positive result on either of these tests makes a syndesmosis injury roughly four times more likely to be present.
The squeeze test, where a clinician compresses the tibia and fibula together at mid-calf level to see if it reproduces ankle pain, is less sensitive but more specific. It’s better at confirming a syndesmosis injury when positive than at ruling one out when negative. Because each test has blind spots, clinicians combine them with the overall pattern of symptoms.
X-rays look for widening of the space between the tibia and fibula, called the tibiofibular clear space. However, X-rays miss a significant number of syndesmosis injuries, particularly partial tears where the widening is subtle. MRI is more reliable for confirming the diagnosis and showing exactly which ligaments are damaged and how severely.
Recovery Takes Longer Than You’d Expect
Recovery from a high ankle sprain is measured in months, not weeks. While a mild lateral ankle sprain can heal in one to three weeks and a moderate one in three to six weeks, a high ankle sprain or severe grade 3 sprain can take several months to fully resolve. Most studies report recovery times roughly double those of a comparable lateral sprain.
Unlike a standard ankle sprain, where early movement and weight-bearing are encouraged, many high ankle sprains require a period of restricted weight-bearing to allow the syndesmosis ligaments to heal properly. You may need a walking boot or crutches during this phase. As you return to activity, the typical progression starts with flat-surface running before reintroducing cutting and jumping movements. Bracing or taping can provide extra stability during the transition back to full activity.
When Surgery Is Needed
Most partial syndesmosis tears heal with time and structured rehabilitation. Surgery becomes necessary when the injury is unstable, meaning the tibia and fibula won’t stay in proper alignment on their own. This usually involves a complete tear of the syndesmosis ligaments with visible widening of the ankle mortise.
Two main surgical approaches exist. The traditional method uses screws to hold the tibia and fibula together while the ligaments heal. A newer technique uses a flexible suture-button device (sometimes called a tightrope) that allows slightly more natural motion at the joint. Research comparing the two shows no clear difference in long-term functional outcomes. The suture-button approach tends to allow an earlier return to work and better range of motion, but it carries a roughly 25% rate of local irritation that sometimes requires a second procedure to remove the device. The screw method is more widely taught and used, though the screw itself sometimes needs removal after healing.
Risks of a Missed Diagnosis
High ankle sprains are frequently misdiagnosed as ordinary ankle sprains, and the consequences of getting it wrong are significant. An untreated syndesmosis injury can lead to chronic ankle instability, persistent activity-related pain, stiffness, and abnormal bone growth around the joint called heterotopic ossification. Over time, the ongoing instability accelerates cartilage breakdown. An untreated syndesmosis injury, like any form of chronic ankle ligament instability, can eventually progress to ankle arthritis.
Late diagnosis is consistently associated with poorer outcomes. If your ankle sprain isn’t improving on the expected timeline, particularly if your pain is above the ankle joint and worsens when you rotate your foot outward, the syndesmosis should be evaluated specifically.