A high ankle sprain involves the ligaments that hold your two lower leg bones together just above the ankle joint, and it takes significantly longer to heal than a typical ankle sprain. Treatment depends on severity: mild to moderate injuries recover with immobilization and structured rehabilitation over 6 to 12 weeks, while severe tears with joint instability often require surgery. Getting the right treatment early matters, because untreated syndesmotic injuries are associated with chronic pain, stiffness, and eventually ankle arthritis.
What Makes a High Ankle Sprain Different
A regular ankle sprain damages the ligaments on the outside of your ankle, usually when your foot rolls inward. A high ankle sprain injures a completely different set of ligaments, located higher up, where the two bones of your lower leg (the tibia and fibula) meet. Four ligaments form this connection, called the syndesmosis, and they work together to keep those two bones properly aligned while you walk, run, and push off the ground.
These injuries typically happen when the foot is forced into an outward rotation while the leg stays planted. Think of a football player whose foot gets trapped under a pile while their body twists, or a skier whose boot forces the foot outward during a fall. The outward twisting puts enormous tension on the front syndesmotic ligament first, and depending on the force, the damage can extend to the other ligaments and even the membrane that runs between the two bones.
Because these ligaments bear load with every step you take, they heal more slowly than lateral ankle ligaments. The blood supply to this area is also relatively limited, which adds to recovery time.
How It’s Diagnosed
High ankle sprains are commonly misdiagnosed as regular ankle sprains, and that delay is linked to significantly worse outcomes. The injury produces pain above the ankle joint rather than below or around the bony bumps on either side. Swelling tends to be less dramatic than with a lateral sprain, which can be misleading.
Clinicians use a combination of physical tests to identify the injury. The squeeze test, where the calf is compressed midway up the lower leg to stress the syndesmosis, has about 85% specificity for detecting these injuries. The external rotation stress test, which reproduces the twisting mechanism, has roughly 78% specificity. Because no single test is perfectly reliable, diagnosis typically involves a cluster of tests followed by imaging. MRI can confirm the extent of ligament damage, while weight-bearing X-rays reveal whether the two bones have separated.
Conservative Treatment for Stable Injuries
If imaging shows the joint is still properly aligned and the ligaments are partially intact, non-surgical treatment is the standard approach. The goal is to protect the healing ligaments from stress while gradually restoring mobility and strength.
Initial Protection Phase
The first priority is reducing pain and swelling. For the first several days, this means rest, compression wrapping, elevation, and ice or a cold compression device. Depending on severity, you may be completely non-weight-bearing on crutches, or you may be able to put partial weight through the foot in a walking boot. More severe injuries may require a cast or rigid splint during this phase. The key rule: you should use crutches until you can walk without a limp, because compensating with an abnormal gait pattern creates new problems.
Progressive Weight-Bearing
The timeline for returning to full weight-bearing varies widely based on injury severity. Mild sprains may allow walking in a boot within the first week. More significant tears can require two to three weeks of protected or partial weight-bearing before the ligaments are stable enough to handle your body weight. Your provider will typically transition you from a boot to a lace-up ankle brace once you can walk comfortably and your range of motion is returning.
Rehabilitation Exercises
Physical therapy is essential, not optional. The rehabilitation process generally moves through three stages: restoring range of motion, rebuilding strength, and retraining balance and coordination.
Early on, gentle ankle circles and towel stretches help recover dorsiflexion, which is the ability to pull your foot upward toward your shin. This motion is often the first to be lost and the slowest to return. As pain allows, you’ll progress to resistance exercises for the muscles along the outside of the lower leg, which provide dynamic support to the syndesmosis. Resistance band exercises where you push your foot outward against the band are a staple at this stage.
Balance training starts simple, with single-leg standing on a flat surface, and advances to unstable surfaces like wobble boards or foam pads. This proprioceptive work retrains the nerve signals between your ankle and brain that help prevent re-injury. Sport-specific drills like cutting, jumping, and change-of-direction work come last, typically in the final weeks before full return to activity.
When Surgery Is Needed
Surgery becomes necessary when the two lower leg bones have visibly separated on imaging, indicating a complete ligament tear. An unstable syndesmosis cannot heal properly on its own because the bones will not stay in the correct position during the healing process.
Two main surgical approaches exist. The traditional method uses one or two screws placed through both bones to hold them together rigidly. This technique has a pooled success rate of about 88%, but the rigid fixation limits normal ankle motion during healing, requires a longer period of protected weight-bearing, and often needs a second surgery to remove the screws before full activity can resume. Screws can also loosen or break.
The newer alternative uses a flexible suture-button device (often called a tightrope). This provides semi-rigid fixation that allows the bones to move more naturally. Because it preserves some motion at the joint, it allows earlier weight-bearing and earlier start of physical therapy. In surgical cases using this method, patients have progressed from non-weight-bearing to partial weight-bearing by day 4, out of a walking boot by days 8 to 12, and to full weight-bearing with normal range of motion by around day 20. The implant does not need to be removed. However, complications can include irritation from the hardware or, rarely, the fixation slipping.
Your surgeon’s recommendation will depend on the severity and pattern of the injury, whether there are associated fractures, and your activity goals.
Recovery Timeline
High ankle sprains take roughly twice as long to heal as lateral ankle sprains, and underestimating the timeline is one of the most common mistakes people make. A mild syndesmotic sprain with conservative treatment typically requires 6 to 8 weeks before return to full activity. Moderate injuries can take 10 to 12 weeks. Surgical cases vary depending on the procedure: screw fixation generally involves a longer protected period, while suture-button fixation can shorten the early recovery phase considerably, though full tissue healing still takes months.
Returning to sports or high-impact activity too early is a significant risk factor for re-injury and chronic instability. Most sports medicine protocols require that you pass functional tests, including single-leg hopping, cutting drills, and sport-specific movements, before clearance.
Risks of Inadequate Treatment
The consequences of undertreating a high ankle sprain are serious. Instability in the syndesmosis, whether from a missed diagnosis or incomplete rehabilitation, leads to abnormal mechanics in the ankle joint. Over time, that abnormal loading damages the cartilage surfaces. Untreated syndesmotic instability will eventually develop into ankle arthritis. Beyond arthritis, poorly managed injuries are associated with chronic activity-related pain, persistent stiffness, and heterotopic ossification, where bone forms in the soft tissue around the joint. These complications are far harder to treat than the original sprain, which is why getting an accurate diagnosis and following through with the full rehabilitation protocol matters so much.