A high ankle sprain is a distinct and often more problematic injury than the common lateral ankle sprain. This injury involves the strong ligamentous structures connecting the tibia and the fibula just above the ankle joint. While a standard ankle sprain typically involves ligaments on the outside of the ankle, this upper injury causes different mechanical instability. It carries a higher potential for prolonged recovery and complications. Any suspicion of this type of injury warrants immediate professional medical assessment to prevent further damage.
Defining the Syndesmosis Injury
The syndesmosis is the fibrous joint held together by three primary ligaments positioned above the main ankle joint. These ligaments—the anterior inferior tibiofibular ligament, the posterior inferior tibiofibular ligament, and the interosseous ligament—act to bind the distal tibia and fibula together. This strong connection ensures the two bones maintain a precise relationship with the talus, the top bone of the foot, which is crucial for ankle stability during movement. The involvement of these ligaments is what leads medical professionals to refer to the injury as a syndesmotic sprain.
Damage typically occurs when the foot is forcibly twisted outward (external rotation) while simultaneously being pushed upward (dorsiflexion). This combination forces the wider front part of the talus bone into the joint space, effectively pushing the tibia and fibula apart. The resulting high-force injury mechanism stretches or tears the syndesmotic ligaments, compromising the stability of the ankle joint.
Weight-Bearing Capacity and Severity
The ability to walk after sustaining a high ankle sprain is highly variable and depends directly on the degree of ligamentous tearing and joint instability. Many individuals find that bearing weight is impossible or causes immediate, sharp pain localized high in the ankle or lower leg. The general advice is to stop all activity and avoid attempting to walk if significant pain is present, especially since continued weight-bearing can worsen the separation between the tibia and fibula.
Syndesmotic injuries are graded on a scale of one to three, which correlates with the severity of the damage and the likelihood of walking. A Grade 1 injury involves a mild stretch of the ligaments, where the joint remains stable, and walking might be possible but uncomfortable. A Grade 2 sprain represents a partial tear, which may or may not cause instability, making walking very painful and often requiring the use of crutches.
A Grade 3 injury involves a complete tear of the syndesmotic ligaments, leading to significant and obvious instability of the ankle joint. In these severe cases, attempting to walk is highly discouraged because it risks widening the gap between the bones, a condition known as diastasis, which could necessitate surgical intervention. Pain and the inability to bear weight serve as immediate indicators of the injury’s severity and the need for non-weight bearing.
Medical Assessment and Confirmation
Self-diagnosis is insufficient for a high ankle sprain because the severity of the internal damage is not always reflected by the external appearance of the ankle. A medical professional will begin the assessment by taking a thorough history of the injury mechanism and performing a physical examination. Specific clinical maneuvers, like the squeeze test, are used to reproduce pain higher up the leg by compressing the tibia and fibula together at the mid-calf.
Another common test is the external rotation stress test, where the foot is gently rotated outward to stress the injured syndesmotic ligaments. Tenderness felt over the ligaments themselves, located on the front of the ankle and lower leg, is a strong clinical indicator of a high ankle sprain. Imaging studies are required to confirm the diagnosis and rule out associated injuries, such as a fracture of the fibula.
Initial X-rays are routinely ordered to check for any abnormal widening of the space between the tibia and fibula, which suggests significant ligament disruption. Stress X-rays, taken while the ankle is gently stressed, may be necessary to reveal instability that is not apparent on standard images. Magnetic Resonance Imaging (MRI) is often preferred for visualizing soft tissues, offering detailed information on the extent of ligament tears and associated damage.
Phased Recovery and Rehabilitation
Recovery for a high ankle sprain is substantially longer than a lateral sprain, often ranging from six weeks to six months, depending on the injury grade. Initial management focuses on protection, often involving non-weight bearing using crutches and immobilization in a cast or walking boot. This acute phase aims to reduce pain and swelling while protecting the healing ligaments from the external rotation forces that caused the injury.
Once the joint is stable and weight-bearing is tolerated without significant pain, the subacute phase of rehabilitation begins. Physical therapy is introduced to restore the normal range of motion, focusing on regaining flexibility and strength in the surrounding muscles. Exercises are carefully progressed to avoid stressing the syndesmosis, which can be easily re-injured by forceful dorsiflexion or external rotation.
The final phase involves advanced training designed to prepare the ankle for a full return to activity, including balance, agility, and sport-specific movements. For Grade 3 injuries with persistent instability, surgical intervention may be required to permanently stabilize the tibia and fibula, significantly extending the recovery period. Throughout the entire process, the progression is guided by the patient’s reduction in pain and the achievement of stability milestones, not by a fixed schedule.