What Is a High Ankle Sprain?

A high ankle sprain — technically a syndesmosis injury — is a sprain of the anterior inferior tibiofibular ligament (AITFL), the posterior inferior tibiofibular ligament (PITFL), and the interosseous membrane that bind the tibia and fibula together above the ankle joint. Unlike a lateral ankle sprain (ATFL/CFL injury), which involves ligaments below the ankle mortise, a syndesmotic injury involves the ligaments that maintain the tibiofibular mortise integrity — the stability of the ankle’s bony socket. High ankle sprains are more serious, require longer recovery, and have a higher rate of return-to-sport complications than lateral sprains. They represent approximately 10–15% of ankle sprains but up to 25% of ankle sprains in contact sports (football, hockey, rugby). At Balance Foot & Ankle in Howell and Bloomfield Hills, Michigan, Dr. Tom Biernacki, DPM evaluates syndesmotic injuries. Call (810) 206-1402.

Mechanism and Why Athletes Are at Higher Risk

High ankle sprains occur from external rotation of the foot relative to the tibia — the foot planted and rotating outward while the body continues forward. This mechanism is common in: football cleat-plant tackles; hockey boot contact mechanisms; skiing with fixed-position boot binding; and twisting falls in basketball with the foot planted. The external rotation force separates the distal tibia and fibula, straining the tibiofibular ligaments. Contact sports create this mechanism repeatedly with blocking and tackling — explaining the higher prevalence in contact athletes.

Diagnosis — Clinical and Imaging

Clinical tests for syndesmotic injury: the squeeze test (compressing the tibia and fibula together at mid-calf produces distal pain at the syndesmosis — positive in 80% of high ankle sprains); the external rotation stress test (reproduces pain at the tibiofibular ligament); and the ankle dorsiflexion test (forced dorsiflexion separates the mortise and reproduces syndesmotic pain). Weight-bearing X-rays are mandatory — tibiofibular clear space >5mm or medial clear space widening indicates mortise instability (Grade III syndesmosis) requiring surgical fixation. MRI evaluates ligament integrity and confirms the diagnosis when clinical tests are equivocal. Weight-bearing CT is the most sensitive for subtle mortise widening.

Conservative Management — Stable Syndesmotic Injury

Grade I–II syndesmotic sprains (ligament stretch or partial tear without mortise instability) are managed conservatively: short-leg non-weight-bearing cast for 2–3 weeks; followed by a cam boot with gradual weight-bearing for 2–3 weeks; physical therapy with proprioceptive retraining and peroneal strengthening; and progressive return-to-sport over 6–10 weeks (compared to 2–4 weeks for lateral ankle sprains). The critical management error: returning to sport based on pain rather than functional testing — syndesmotic injuries frequently feel better before they are structurally healed, and premature return creates chronic instability. The single-leg heel rise test at full speed without pain is the functional clearance criterion.

Surgical Management — Unstable Syndesmosis

Grade III syndesmotic injury with mortise widening on stress X-ray or CT requires surgical stabilization: syndesmotic fixation with a cortical screw or suture-button construct (TightRope) that compresses the tibia and fibula together while allowing slight physiologic motion; recovery 8–12 weeks non-weight-bearing, 4–6 months to full competitive return. The suture-button construct is increasingly preferred over screw fixation — it allows the 2° of physiologic fibular rotation that occurs during ankle dorsiflexion, reducing the stiffness and hardware failure associated with rigid screw fixation.

Syndesmosis Injury Management in Howell & Bloomfield Hills Michigan

Dr. Tom Biernacki, DPM evaluates syndesmotic injuries with clinical testing, weight-bearing stress X-rays, and MRI coordination at Balance Foot & Ankle. Same-day evaluation available for athletes with acute ankle injuries. Serving Howell, Brighton, Bloomfield Hills, Troy, Auburn Hills, and all Southeast Michigan. Book your evaluation or call (810) 206-1402.

Dr. Tom Biernacki, DPM

Dr. Tom Biernacki, DPM is a double board-certified podiatrist and foot & ankle surgeon at Balance Foot & Ankle Specialists in Southeast Michigan. With over a decade of clinical experience, he specializes in heel pain, bunions, diabetic foot care, sports injuries, and minimally invasive surgery. Dr. Biernacki is a member of the APMA and ACFAS, and his patient education content on MichiganFootDoctors.com and YouTube has reached over one million views.