Ankle sprain

Background

Ankle stabilization anatomy

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

Clinical Features

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")

• Assoc 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 Fractures

• 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 Fractures

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

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
  • Immoblize 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:
  • NSAIDs, RICE (rest, ice, compression, elevation)
  • 1 week follow up if no improvement
• Stable joint but unable to bear weight:
  • Ankle brace with follow up in 1wk
• Unstable joint
  • Posterior mold splint and ortho consult/referral

Disposition

• Outpatient

See Also

• Ankle (Main)
• Ankle Fracture
• Ottowa Ankle Rules

References

• American Orthopaedic Foot and Ankle Society (September 2012) - http://orthoinfo.aaos.org/topic.cfm?topic=a00150

Authors

Ross Donaldson