II. Epidemiology

  1. Lateral sprains represent 80-85% of Ankle Sprains
  2. Sports with highest rate of Ankle Sprain
    1. Basketball
    2. Ice skating
    3. Soccer

III. Mechanism

  1. Ankle Inversion with Plantar Flexion

IV. Pathophysiology

  1. Anatomy
    1. See Ankle Anatomy
  2. Lateral ankle ligaments (In order of injury)
    1. Anterior talofibular ligament (ATF): Easily injured
    2. Calcaneofibular ligament (CF)
    3. Posterior Talofibular ligament (PTF): Rarely injured (third degree sprain)
  3. TibioFibular Ligaments
    1. See High Ankle Sprain
    2. Anterior tibiofibular ligament
    3. Posterior tibiofibular ligament
  4. Medial ankle ligament
    1. See Medial Ankle Sprain
    2. Ankle Deltoid Ligament (rarely injured, but associated with serious ankle injury)

V. Associated Conditions: Other associated Injuries

  1. Peroneal Tendon Injury
    1. Peroneal tendon avulsion Fracture
      1. Distinguish from Jones Fracture
      2. Everts foot and prevents inversion
      3. Palpate lateral foot at its insertion
    2. Hemorrhage at Peroneal Muscle
    3. Peroneal Nerve damage may occur
  2. Bone Injury: Foot
    1. Jones Fracture at fifth Metatarsal metaphysis
      1. Peroneal brevis tendon avulsion Fracture
      2. May require surgery for non-union
    2. Tarsal Navicular Fracture (or Stress Fracture)
    3. Lisfranc Fracture-Dislocation (uncommon, but high morbidity)
  3. Bone Injury: Fibula
    1. Pott's Fracture-Subluxation
    2. Maisonneuve Injury (Proximal Fibula Fracture related to Syndesmotic Sprain)
  4. Bone Injury: Talus
    1. Talar Dome Fracture (occurs in 6 to 22% of cases)
    2. Posterior Talus Fracture (Medial or Lateral Tubercle)
    3. Lateral process of Talus Fracture (most commonly missed Ankle Fracture)
  5. Bone Injury: Calcaneus
    1. Calcaneus Anterior Process Fracture

VI. Differential Diagnosis: Delayed healing

  1. Unrecognized associated injury as listed above
  2. Talar Dome Fracture
  3. Reflex Sympathetic Dystrophy
  4. Chronic Tendonitis
  5. Peroneal tendon subluxation
  6. Syndesmotic Sprain (High Ankle Sprain)
  7. Occult Fracture
    1. Anterior Superior Calcaneus Fracture
    2. Lateral Talus Fracture

VII. Symptoms

  1. "Pop" heard with injury
  2. Ankle swelling and decreased function
  3. Inability to walk four feet after Ankle Sprain is higher risk of Fracture
    1. See Ottawa Ankle Rules

VIII. Signs

  1. See Ankle Exam
  2. See Ankle Anatomy
  3. Ankle Motor Function (Always assess)
  4. Evaluate for Syndesmotic Sprain (High Ankle Sprain)
    1. Crossed-Leg Test
    2. Squeeze Test
  5. Evaluate ankle stability
    1. More useful at follow-up at 4-6 weeks after Ankle Sprain
      1. Used in grading Ankle Sprain (see below)
      2. Does not typically modify initial management after acute injury
    2. Ankle Anterior Drawer Test
      1. Tests anterior talofibular ligament integrity
    3. Ankle Talar Tilt (Inversion stress Test)
      1. Tests calcaneofibular ligament integrity
  6. Evaluate for associated Fracture
    1. See Ottawa Ankle Rules
    2. Ankle bony tenderness
      1. Medial malleolus or distal tibia tenderness within last 2.4 inches (6 cm)
        1. May also indicate Growth Plate Fracture in adolescent
      2. Lateral malleolus or distal fibula tenderness within last 2.4 inches (6 cm)
      3. Talocrural joint line (anterior talar dome) tenderness or swelling
        1. May indicate osteochondral Talar Dome Fracture
        2. Not part of Ottawa Ankle Rules
    3. Foot bony tenderness (midfoot)
      1. Fifth Metatarsal tenderness or pain at base or metaphysis (e.g. Jones Fracture)
      2. Tarsal Navicular tenderness or pain at medial, proximal foot (Tarsal Navicular Fracture)
      3. Lisfranc Joint tenderness, swelling or deformity at midfoot region (Lisfranc Fracture Dislocation)

IX. Evaluation: Red Flags suggestive of more complicated injury

  1. See Ottawa Ankle Rules
  2. Mechanism different than classic inversion injury
    1. Eversion injury (see Medial Ankle Sprain)
    2. Forced severe plantar flexion (see Fifth Metatarsal Fracture)
    3. Dorsiflexion
  3. Atypical signs on acute evaluation immediately after injury
    1. See signs above (under evaluate for associated Fracture)
    2. Immediate swelling or Bruising over the forefoot or toes
  4. Children with tenderness over physis
    1. Suspect Salter-Harris Fracture I (physis is weaker than ligaments)
    2. Safest to apply splint despite negative XRay
    3. Low risk of Salter Harris I Fractures on MRI in these patients
      1. Boutis (2016) JAMA Pediatr 170(1): e154114 +PMID: 26747077 [PubMed]

X. Imaging: Initial

  1. Ankle XRay Indications
    1. See Ottawa Ankle Rules (adults and children over age 5 years old)
    2. See Low Risk Ankle Rule (children over age 3 years old)
    3. See ankle bony tenderness above
    4. Inability to walk four feet at injury site (e.g. sideline) or at acute evaluation by medical provider
  2. Foot XRay Indications
    1. See foot bony tenderness above

XI. Imaging: Delayed healing (suspected Talar Dome OCD)

  1. Indications
    1. Symptomatic beyond 6 weeks
    2. Persistent crepitus
    3. Locking or catching Sensation
  2. Imaging
    1. Repeat Ankle XRay and foot XRay
    2. Ankle CT or Ankle MRI

XII. Grading

  1. Indications
    1. Ankle stability at 4-6 weeks after Ankle Sprain
      1. Instability directs additional management with rehabilitation (or possibly surgery for third degree Ankle Sprain)
    2. Inaccurate and not useful on initial Ankle Sprain evaluation
      1. Does not modify initial management
  2. First degree Lateral Ankle Sprain
    1. Mild pain and swelling (able to ambulate)
    2. No mechanical instability
    3. Anterior talofibular ligament stretched
    4. Localized tenderness anteriorly
  3. Second degree Lateral Ankle Sprain
    1. Moderate pain and swelling with Ecchymosis present
    2. Pain with ambulation
    3. Moderate lateral ankle instability
    4. Partial tear of anterior talofibular ligament
  4. Third degree Lateral Ankle Sprain
    1. Severe Ecchymosis and swelling (>4 cm at fibula)
    2. Unable to bear weight
    3. Severe lateral ankle instability
    4. Total disruption of lateral ligaments
      1. Anterior talofibular ligament
      2. Calcaneofibular ligament
    5. Heard "Pop" with immediate pain and swelling

XIII. Management

XIV. Prognosis

  1. Outcomes generally good
  2. Full recovery may require months
    1. Severe Lateral Ankle Sprains
    2. Syndesmotic Sprains (High Ankle Sprains)

XV. Complications (rare)

  1. Late Traumatic Arthritis
  2. Chronic instability

Images: Related links to external sites (from Bing)

Related Studies

Ontology: Ankle Sprains (C0160087)

Concepts Injury or Poisoning (T037)
MSH D016512
ICD9 845.00, 845.0
ICD10 S93.4 , S93.40
SnomedCT 157297008, 269333001, 209537006, 157299006, 263132007, 209530008, 44465007
English Ankle sprain NOS, Ankle sprain, unspecified, Sprn ligament ankle joint, ankle sprain, ankle sprain (diagnosis), Sprain of ankle NOS, Sprained ankle NOS, Sprain;ankle, sprained ankle, ankle sprains, ankles sprain, Sprained ankle, Unspecified site of ankle sprain, Ankle sprains, Sprain of ankle, unspecified site, Sprain, Ankle, Sprains, Ankle, Ankle Sprains, Ankle Sprain, (Sprain - ankle NOS) or (twisted ankle) (disorder), Sprain of ligament of ankle joint (disorder), Sprain - ankle NOS, Ankle sprain, unspecified (disorder), (Sprain - ankle NOS) or (twisted ankle), Twisted ankle, Ankle sprain NOS (disorder), Sprain of ankle joint (disorder), Ankle sprain, Sprain of ankle joint, Sprain of ligament of ankle joint, Sprain of ankle (disorder), Sprain of ankle, Sprain of ankle, NOS
Spanish Esguince de una zona no especificada del tobillo, Esguince de tobillo, Torcedura de tobillo, esguince del tobillo, estrema de tobillo, esguince de tobillo (trastorno), esguince del tobillo (trastorno), esguince de tobillo, esguince de tobillo, no especificado (trastorno), esguince de tobillo, SAI (trastorno), esguince de tobillo, SAI, esguince de tobillo, no especificado
Portuguese Entorse do tornozelo, Tornozelo com entorse, Localização NE de entorse do tornozelo
Dutch enkelverstuiking, verstuikte enkel, niet-gespecificeerde plaats van enkelverstuiking
French Entorse d'un site non précisé de la cheville, Entorse - cheville, Entorse de la cheville
German unspezifische Stelle einer Knoechelverstauchung, Knoechelverstauchung, Verstauchung des Knoechels
Hungarian Megrándult boka, Bokahúzódás, nem meghatározott lokalizáció, Bokarándulás
Czech Podvrtnutý kotník, Neurčené podvrtnutí kotníku, Podvrtnutí kotníku
Italian Distorsione della caviglia a sede non specificata, Caviglia distorta, Distorsione della caviglia
Japanese 足関節捻挫, アシカンセツネンザ, 足関節捻挫、部位不明, アシカンセツネンザブイフメイ, ソクカンセツネンザブイフメイ, ソクカンセツネンザ

Ontology: Calcaneofibular (ligament) ankle sprain (C0160090)

Concepts Injury or Poisoning (T037)
ICD9 845.02
English Sprain calcaneofibular, Calcaneofibular (ligament) ankle sprain, Sprain of calcaneofibular (ligament) of ankle, Calcaneofibular ligament ankle sprain, Calcaneofibular ankle sprain
Spanish Esguince (del ligamento) calcaneoperoneo del tobillo
Portuguese Estiramento do ligamento calcaneoperoneal
Dutch calcaneofibulair (ligament) enkelverstuiking
French Entorse du ligament calcanéo-péronier
German kalkaneofibulare (Ligament) Knoechelverstauchung
Hungarian Calcaneofibularis (szalag) bokarándulás
Czech Podvrtnutí kalkaneofibulárního (vazu) kotníku
Italian Distorsione del (legamento) calcaneofibulare
Japanese 足関節踵腓(靱帯)捻挫, ソクカンセツショウヒジンタイネンザ, アシカンセツショウヒジンタイネンザ

Ontology: Sprain, ankle joint, lateral (C0434477)

Concepts Injury or Poisoning (T037)
SnomedCT 209532000
English Sprain, ankle joint, lateral, Sprain, ankle joint, lateral (disorder)
Spanish esguince de articulación del tobillo, lateral (trastorno), esguince de articulación del tobillo, lateral

Ontology: talofibular; sprain (strain) (C1395626)

Concepts Injury or Poisoning (T037)
English sprain (strain); talofibular, talofibular; sprain (strain)
Dutch distorsie; talofibulair, talofibulair; distorsie