Musculoskeletal · PANCE / PANRE

Ankle Sprain

Inversion injury to the lateral ligaments (ATFL most common); Ottawa rules guide imaging; functional rehabilitation outperforms immobilization.

Also known as: ankle sprain, lateral ankle sprain, ATFL sprain, high ankle sprain, syndesmosis injury

Overview

Stretch or tear of the ankle ligaments, most commonly the lateral ligament complex (anterior talofibular ligament — ATFL, calcaneofibular ligament — CFL, posterior talofibular ligament — PTFL) from inversion injury. Less common are medial (deltoid ligament) sprains from eversion and 'high ankle' syndesmotic sprains.

Epidemiology

One of the most common musculoskeletal injuries in athletes and the general population. Incidence highest in court and field sports. Recurrent sprains common — up to 30% develop chronic ankle instability.

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Risk factors

Sports — basketball, soccer, volleyball, running on uneven terrain
Prior ankle sprain (strongest single risk factor)
Inadequate rehabilitation after prior injury
Female sex (sport-controlled)
Ligamentous laxity
High-arched feet (cavus foot)
Improper footwear

Pathophysiology

Plantarflexion and inversion stress (rolled ankle) loads the lateral ligaments. The ATFL fails first (most common isolated injury), then the CFL with more severe injury; PTFL rarely torn except in dislocation. Eversion injuries can sprain the deltoid ligament. External rotation force with dorsiflexed foot can tear the tibiofibular syndesmosis (high ankle sprain).

Clinical presentation

Symptoms

Acute inversion injury with immediate lateral ankle pain
Swelling and bruising over the lateral malleolus
Difficulty bearing weight (variable)
Sense of giving way
High ankle sprain: pain is more proximal and anterior, longer recovery

Signs / physical exam

Tenderness over ATFL (anterolateral to lateral malleolus, between fibula and talar neck) and CFL (inferior to lateral malleolus)
Swelling and ecchymosis
Anterior drawer test (sensitive for ATFL)
Talar tilt test (CFL)
Squeeze test of mid-calf and external rotation stress test — positive in syndesmotic injury
Apply Ottawa ankle rules to decide imaging
Check medial malleolus, base of 5th metatarsal, and navicular for tenderness

Differential diagnosis

Lateral malleolus fracture (Weber A/B/C) — Bony tenderness at malleolus, inability to bear weight; Ottawa rules guide imaging
Fifth metatarsal base fracture (Jones, avulsion) — Tenderness at base of 5th MT after inversion; X-ray
Maisonneuve fracture — Proximal fibula fracture with syndesmotic injury; tender along entire fibula
Talar dome osteochondral lesion — Persistent pain after sprain, mechanical symptoms; MRI
Peroneal tendon subluxation or tear — Lateral retromalleolar pain, snapping with eversion
Achilles tendon rupture — Posterior calf pain, palpable defect, positive Thompson test; older adult or athlete jumping/pushing off
Syndesmotic (high ankle) sprain — Pain anterolateral above the joint line; positive squeeze and external rotation tests; slower recovery
Tarsal coalition — Pediatric/adolescent; recurrent 'sprains', restricted subtalar motion

Diagnostic workup

Labs

Not indicated

Imaging

Apply OTTAWA ANKLE RULES — radiograph if any of:
• Bony tenderness at posterior edge or tip of distal 6 cm of lateral malleolus
• Bony tenderness at posterior edge or tip of distal 6 cm of medial malleolus
• Inability to bear weight (4 steps) both immediately and in the ED
Ottawa FOOT rules add 5th MT base and navicular tenderness criteria
MRI — for persistent pain, suspected osteochondral lesion, peroneal tendon injury, or refractory chronic instability
Ultrasound — operator-dependent; can evaluate ligaments and tendons

Diagnostic algorithm

Ottawa Ankle/Foot Rules — Image if any of:
Bony tenderness at posterior edge or tip of distal 6 cm of LATERAL malleolus
Bony tenderness at posterior edge or tip of distal 6 cm of MEDIAL malleolus
Inability to bear weight (4 steps) both immediately AND in the ED
Foot rules add: bony tenderness at base of 5TH METATARSAL
Bony tenderness over the NAVICULAR
Inability to bear weight as above

Ottawa ankle and foot rules — high sensitivity (~99%) for fracture; allow safe imaging stewardship.

Complications

Recurrent sprains — up to 30%
Chronic ankle instability — mechanical and functional
Post-traumatic osteoarthritis
Osteochondral lesion of the talus (suspect with persistent pain or mechanical symptoms)
Peroneal tendon pathology
Persistent pain ('high ankle' sprains particularly slow to heal)
DVT (rare; consider in prolonged immobilization)

PANCE pearls

Always apply the Ottawa ankle and foot rules — they reliably identify which patients need radiographs.
Early functional rehabilitation with proprioceptive training is more effective than prolonged immobilization.
Persistent ankle pain >6 weeks after a sprain — consider talar dome osteochondral lesion or peroneal tendon pathology and obtain MRI.
High ankle (syndesmotic) sprains heal slowly — counsel patients to expect months, not weeks.
Recurrent sprains usually indicate inadequate proprioceptive rehabilitation, not necessarily ligamentous incompetence.

References

Ottawa Rules — Stiell IG et al. Implementation of the Ottawa Ankle Rules (JAMA 1994; validated in many subsequent studies)
JOSPT 2021 — Ankle Stability and Movement Coordination Impairments: Clinical Practice Guideline (Martin et al., J Orthop Sports Phys Ther 2021)
AAOS 2018 — AAOS Clinical Practice Guideline on Management of Ankle and Foot Conditions (selected guidelines)

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