Ankle sprain

Background

Ankle stabilization anatomy

Ligaments of ankle and feet.

• Syndesmosis
• Ligaments
  • Medial: Medial collateral (deltoid) ligament (tibia to talus and calcaneus)
  • Lateral: Anterior/posterior talofibular, calcaneofibular ligaments

Clinical Features

Right foot with acute lateral ankle sprain.

Lateral Ankle Sprain

• Most common
• Due to inversion of plantarflexed ankle
• Anterior talofibular ligament (ATFL) is most commonly injured ligament

Medial Ankle Sprain

• Isolated sprain is unusual; often associated with fibular fracture or syndesmosis injury
• Always rule-out Maisonneuve fracture by evaluating proximal fibula

Syndesmotic Sprain ("High-ankle sprain")

• Associated with with hyperdorsiflexion when talus moves superiorly and separates tibia/fibula
• Pain just above talus

Differential Diagnosis

Other Ankle Injuries

• Ankle sprain
• Ankle dislocation
• Ankle syndesmosis injury
• Radiograph-negative ankle injury (peds)

Distal Leg Fracture Types

• Tibial plateau fracture
• Tibial shaft fracture
• Pilon fracture
• Maisonneuve fracture
• Tibia fracture (peds)
• Ankle fracture
  • Ankle fracture (peds)
    • Tillaux fracture
• Foot and toe fractures

Foot and Toe Fracture Types

Hindfoot

• Talus fracture
• Calcaneus fracture

Midfoot

• Lisfranc injury
• Navicular fracture
• Cuboid fracture
• Cuneiform fracture

Forefoot

• Fifth metatarsal fracture
• Non-fifth metatarsal fracture
• Toe fracture

Evaluation

• Anterior drawer test
  • Tests anterior talofibular ligament
  • Cup heel with one hand and and pull anteriorly while pushing tibia posteriorly
• Talar tilt test
  • Tests for combined injury of anterior talofibular and calcaneofibular ligaments
  • Inversion at the ankle causes tilting/lifting of the mortise joint

Ottawa ankle rule

Ottawa ankle rule

Ankle x-ray needed if:

• Pain near the maleoli AND
• Inability to bear weight immediately and in the ED (4 steps) OR
• Tenderness at posterior edge or tip of lateral malleolus OR
• Tenderness at posterior edge or tip of medial malleolus

Ottawa foot rules

Ottawa foot rules

Foot x-ray series needed if:

• Pain in the midfoot AND
• Inability to bear weight both immediately and in the ED (4 steps) OR
• Tenderness at the navicular OR
• Tenderness at the base of the 5th metatarsal

Exceptions

• Age <6 or >55
• Only for blunt trauma mechanism
• Does not apply to subacute/chronic injuries
• Does not apply to injuries of the hindfoot or forefoot

Classification

• Grade I
  • No tearing of ligaments
  • Minimal pain, swelling, ecchymosis; weightbearing is tolerable
  • No splinting/casting; weight bearing as tolerated, isometric exercises, full ROM and stretching/strengthening exercises
• Grade II
  • Partial ligament tear; possible instability
  • Increased pain, swelling, ecchymosis; difficulty bearing weight
  • Immobilize with air splint; PT with ROM/stretching/strengthening exercises
• Grade III
  • Complete ligament tear; significant instability
  • Severe pain, swelling, ecchymosis; inability to bear weight
  • Immobilization and possible surgery; PT same as grade 2 but longer time period

Management

• Stable joint and ability to bear weight: (Likely Grade I)
  • NSAIDs, RICE (rest, ice, compression, elevation)
  • 1 week follow up if no improvement
• Stable joint but unable to bear weight or unstable joint (Grades II and III) :
  • Ankle cast immobilization or a removable walking boot for 7-10 days for grades II and III. Follow up at 5 days with ortho/podiatry.
  • Posterior mold splint and ortho consult/referral

Disposition

• Discharge

Calculators

Ottawa Ankle Rules

Ottawa Ankle Rule

Criteria	No (0)	Yes (+1)
Ankle X-ray is required if there is pain in the malleolar zone AND any of the following:
Bone tenderness along distal 6 cm of posterior edge of tibia or tip of medial malleolus	1
Bone tenderness along distal 6 cm of posterior edge of fibula or tip of lateral malleolus	1
Inability to bear weight both immediately and in the ED (4 steps)	1
Foot X-ray is required if there is pain in the midfoot zone AND any of the following:
Bone tenderness at the base of the 5th metatarsal	1
Bone tenderness at the navicular	1
Inability to bear weight both immediately and in the ED (4 steps)	1
Positive Criteria	/ 6

Interpretation
Score = 0	No X-ray needed — Sensitivity 96.4–99.6% for clinically significant fractures.
Score ≥ 1	X-ray recommended — Ankle and/or foot x-ray indicated based on positive criteria location.

References
Stiell IG et al. A study to develop clinical decision rules for radiography in acute ankle injuries. Ann Emerg Med. 1992;21:384-390. PMID 1554175. Stiell IG et al. Decision rules for radiography in acute ankle injuries: refinement and prospective validation. JAMA. 1993;269:1127-1132. PMID 8433468.

See Also

• Ankle (Main)
• Ankle Fracture
• Ottawa Ankle Rules