A high ankle sprain, medically termed a syndesmotic injury, involves damage to the ligaments that connect the two long bones of the lower leg. These injuries are distinctly different from the more common lateral ankle sprain, which affects the ligaments on the outside of the ankle joint. While less frequent, a high ankle sprain is generally considered a more serious injury requiring a significantly longer recovery period. This severity stems from the injury’s impact on the overall stability of the ankle complex, which is fundamental for walking and bearing weight.
What Makes a High Ankle Sprain Different
A high ankle sprain targets the syndesmosis, a group of strong ligaments that hold the tibia (shin bone) and the fibula (calf bone) together just above the ankle joint. These ligaments include the anterior inferior tibiofibular ligament (AITFL), the posterior inferior tibiofibular ligament (PITFL), and the interosseous membrane. Together, they create the ankle mortise, a stable socket that the ankle bone fits into.
The mechanism of injury is typically a forceful external rotation of the foot while the ankle is bent upward (dorsiflexed). This motion forces the talus bone to wedge between the tibia and fibula, tearing the syndesmotic ligaments and destabilizing the joint. Damage to these ligaments compromises the ankle’s ability to withstand the extreme forces encountered during walking and running.
Grading the Severity and Initial Treatment Options
Clinicians use a grading system to categorize the severity of a high ankle sprain, which determines the appropriate course of treatment and recovery timeline. A Grade I sprain involves a mild stretch or partial tear of the ligaments, with the joint remaining stable under physical examination. A Grade II injury signifies a more significant, though incomplete, tear, which may or may not result in joint instability. The most severe injury, a Grade III sprain, is a complete rupture of the ligaments, causing the joint to become visibly unstable.
Diagnosis often involves specific clinical tests, such as the squeeze test, where a healthcare provider compresses the tibia and fibula together higher up the leg to elicit pain. Imaging, including X-rays and sometimes stress X-rays, is used to check for a widening of the space between the bones, known as diastasis, and to rule out associated fractures. Magnetic resonance imaging (MRI) can provide a detailed view of the ligament damage itself.
For stable Grade I and some Grade II injuries, treatment is non-surgical, focusing on rest, protection, and pain management. This initial phase often involves non-weight-bearing, followed by progressive weight bearing in a protective boot or brace. If the joint is determined to be unstable, typically seen in Grade III sprains, surgical intervention is required to physically hold the bones together. This surgical fixation is commonly achieved using a specialized screw or a flexible “tightrope” device placed between the tibia and fibula to restore proper alignment while the ligaments heal.
The Phased Approach to Recovery and Rehabilitation
The recovery from a high ankle sprain is generally broken down into several phases, often taking substantially longer than a typical ankle sprain. For non-surgical Grade I or II injuries, recovery can range from 6 to 12 weeks, while surgical cases may require three to six months or more before a full return to activity.
The first phase is Protection, which focuses on reducing pain and swelling and protecting the injured ligaments from further stress. This initial period typically lasts between two and four weeks, often requiring complete non-weight-bearing using crutches, especially for more severe injuries.
Once pain and swelling have decreased, the second phase, Early Mobility, begins with the goal of safely restoring the ankle’s range of motion. Exercises focus on gentle movement, avoiding forced dorsiflexion and external rotation, which would stress the healing syndesmosis.
As weight-bearing becomes tolerated, the third phase introduces Strength and Proprioception training, which is crucial for long-term stability. This phase involves targeted exercises to rebuild the strength of the surrounding muscles and to retrain the body’s sense of joint position and balance. This neuromuscular control work progresses from simple exercises like single-leg stance to more dynamic movements on unstable surfaces. Progression through these phases is determined by functional milestones rather than fixed timelines.
Criteria for Returning to Sports and Activity
Returning to high-level activity or sport after a high ankle sprain requires meeting a stringent set of functional criteria to minimize the risk of re-injury and chronic instability. Time alone is an insufficient measure, and clearance is granted only after a thorough assessment of the ankle’s readiness to handle dynamic loads.
One of the first criteria is achieving full, pain-free range of motion in the ankle, particularly in dorsiflexion. The injured leg must also demonstrate near-equal strength compared to the uninjured leg, with a common benchmark being 90 to 100% of pre-injury strength. This is often tested through specific resistance and power exercises.
Functional testing then progresses to sport-specific movements, such as jumping, hopping, cutting, and sprinting. These movements must be performed without pain, limping, or excessive compensation. Finally, the athlete’s psychological readiness and confidence in the ankle’s stability are considered before they are cleared for unrestricted training and competition.