🧠 An ankle sprain is an injury to the ankle ligaments, usually caused by twisting or inversion of the foot. Most are lateral ligament injuries, especially involving the anterior talofibular ligament (ATFL). The key clinical task is to exclude fracture, syndesmotic injury, tendon rupture and neurovascular compromise.

📖 About

Common injury after twisting the ankle during sport, walking on uneven ground, falls or missteps.
Usually affects the lateral ligament complex.
The most commonly injured ligament is the anterior talofibular ligament.
More severe inversion injuries may also damage the calcaneofibular ligament.
Medial ankle sprains are less common because the deltoid ligament is stronger.
High ankle sprain = injury to the syndesmosis between tibia and fibula.

🧬 Relevant Anatomy

Structure	Mechanism	Clinical clue
Anterior talofibular ligament ATFL	Inversion with plantarflexion	Most common sprain; tenderness anterior to lateral malleolus.
Calcaneofibular ligament CFL	More severe inversion injury	Tenderness inferior to lateral malleolus; instability may be greater.
Posterior talofibular ligament PTFL	Severe ankle trauma/dislocation	Rarely isolated; suggests major injury.
Deltoid ligament	Eversion injury	Medial ankle pain; consider associated fracture or syndesmotic injury.
Syndesmosis	External rotation / dorsiflexion injury	Pain above ankle joint, positive squeeze/external rotation test; slower recovery.

⚙️ Mechanism

🌀 Inversion injury — foot rolls inwards; commonest mechanism.
🏃 Sports involving jumping, pivoting or sudden direction change.
🪨 Uneven ground or missing a step.
⚠️ External rotation injury may suggest syndesmotic/high ankle sprain.
🦴 Severe trauma or inability to weight bear raises concern for fracture.

🩺 Clinical Features

Sudden ankle pain after twisting injury.
Swelling around the lateral ankle, often developing rapidly.
Bruising may appear over hours to days.
Tenderness over ATFL/CFL region.
Pain on weight bearing, walking, inversion or plantarflexion.
Sense of instability or “giving way” in more severe sprains.
Reduced range of movement due to pain and swelling.

🚩 Red Flags / Alternative Diagnoses

Inability to weight bear immediately and in clinic/ED.
Bony tenderness over posterior edge/tip of medial or lateral malleolus.
Tenderness at the base of the 5th metatarsal.
Tenderness over the navicular.
Marked deformity or suspected dislocation.
Neurovascular compromise: numbness, pallor, cold foot, weak pulses.
Pain high above ankle joint → possible syndesmotic injury.
Palpable Achilles gap or positive calf squeeze test → Achilles rupture.
Severe persistent pain despite normal X-ray → consider occult fracture, osteochondral injury or tendon injury.

🧪 Examination

Step	What to assess
Look	Swelling, bruising, deformity, wounds, foot position.
Feel	Lateral ligaments, medial ligament, malleoli, base of 5th metatarsal, navicular, Achilles tendon, proximal fibula.
Move	Active and passive dorsiflexion, plantarflexion, inversion and eversion.
Function	Ability to weight bear and walk four steps.
Neurovascular	Dorsalis pedis/posterior tibial pulses, capillary refill, sensation and movement.
Special tests	Anterior drawer/talar tilt if tolerated; squeeze/external rotation test if syndesmosis suspected.

🦴 Ottawa Ankle Rules — When to X-ray

📌 Use the Ottawa ankle rules to decide whether an ankle or foot X-ray is needed after acute injury.

X-ray area	Indication
Ankle X-ray	Pain in the malleolar zone plus either: Bone tenderness at the posterior edge or tip of the lateral malleolus, or Bone tenderness at the posterior edge or tip of the medial malleolus, or Inability to weight bear both immediately and for four steps during assessment.
Foot X-ray	Pain in the midfoot zone plus either: Bone tenderness at the base of the 5th metatarsal, or Bone tenderness at the navicular, or Inability to weight bear both immediately and for four steps during assessment.

🖼️ Imaging

X-ray: if Ottawa ankle rules are positive, deformity is present, or fracture/dislocation is suspected.
Ultrasound: not usually needed for simple ankle sprain, but may help assess tendon injury in selected cases.
MRI: not routine in the acute phase of a simple ankle sprain; consider specialist-led MRI if persistent pain, suspected syndesmotic injury, osteochondral lesion, occult fracture, tendon injury, or failure to improve despite rehabilitation.
Stress imaging: rarely needed acutely; usually specialist-led if chronic instability is suspected.

📊 Severity Grading

Grade	Injury	Clinical picture	Recovery
Grade I	Ligament stretch / microscopic tear	Mild pain, minimal swelling, able to weight bear.	Usually days to 2 weeks.
Grade II	Partial ligament tear	Moderate pain, swelling, bruising, painful walking, some instability.	Often 2–6 weeks.
Grade III	Complete ligament rupture	Severe swelling/bruising, marked instability, difficulty weight bearing.	Often 6–12 weeks or longer; may need specialist review.

🏥 Initial Management — PRICE / POLICE

Protection: avoid painful activities and further injury for the first 48–72 hours.
Relative rest: avoid complete immobilisation unless severe injury or fracture is suspected.
Optimal loading: begin gentle movement and weight bearing as pain allows.
Ice: may help pain and swelling in the first 48–72 hours; wrap ice pack in a towel to avoid ice burns.
Compression: elastic bandage or ankle support can reduce swelling.
Elevation: raise ankle above heart level when resting.
Analgesia: paracetamol ± NSAID if appropriate; consider topical NSAID.
Rehabilitation: progressive range-of-movement, strengthening and balance/proprioception exercises reduce recurrent sprain risk.

🚶 Rehabilitation

Phase	Goals	Examples
Early phase 0–3 days	Reduce pain/swelling, protect injury, maintain gentle movement.	Elevation, compression, ankle circles, gentle dorsiflexion/plantarflexion, weight bear as tolerated.
Recovery phase 3 days–2 weeks	Restore range of movement and normal walking.	Walking practice, calf stretches, resisted band exercises, gradual return to daily activity.
Strength / balance phase 2–6 weeks	Improve strength, proprioception and stability.	Single-leg stance, wobble board, heel raises, resisted eversion/inversion.
Return to sport	Restore agility, power and confidence.	Hopping, cutting, running drills, sport-specific training; ankle brace/taping may reduce recurrence.

📅 Follow-Up / Referral

Mild sprain: self-care advice, early mobilisation and safety-netting.
Moderate sprain: consider physiotherapy, ankle support and review if not improving.
Severe sprain: fracture clinic, MSK or physiotherapy review depending on local pathway.
Urgent referral: fracture/dislocation, neurovascular compromise, open injury, suspected syndesmotic injury, Achilles rupture, tendon injury, or inability to weight bear with concerning signs.
Persistent symptoms: review if pain, swelling, instability or inability to return to function persists beyond 4–6 weeks.

⚠️ Complications

Chronic ankle instability and recurrent sprains.
Persistent swelling and stiffness.
Peroneal tendon injury.
Osteochondral lesion of the talus.
Missed fracture, especially base of 5th metatarsal, lateral process of talus, posterior malleolus or navicular.
Complex regional pain syndrome, rarely.

💡 Clinical Pearls

Most ankle sprains are lateral ligament injuries from inversion.
Use Ottawa ankle rules to decide on X-ray after acute injury.
Ability to walk does not fully exclude serious injury, but inability to weight bear is a key imaging trigger.
High ankle sprains hurt above the ankle joint and recover more slowly.
Early functional rehabilitation reduces stiffness and recurrent sprain risk.
Persistent pain after a “sprain” needs reassessment for occult fracture, syndesmotic injury or osteochondral lesion.

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Sprained Ankle ✅