Ankle Fracture

Aka: Ankle Fracture, Ankle Fracture Weber Classification, Bimalleolar Fracture, Trimalleolar Fracture, Tibia-Fibula Fracture, Tib-Fib Fracture, Weber Fracture Types, Weber A Fracture, Weber B Fracture, Weber C Fracture, Danis-Weber Lateral Ankle Fracture Classification

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II. Epidemiology

  1. Ankle Fractures account for 15% of acute ankle injuries

III. Pathophysiology

  1. Ankle is an inherently unstable joint (esp. given Talus shape)
    1. Ankle is most unstable when plantar flexed (with increased risk of Fractures and dislocations)
  2. Other risk factors
    1. High risk sports
    2. Increased Body Mass Index increases risk of ankle injury with less force

IV. Types

  1. Medial Ankle Fractures
    1. Isolated Medial Malleolus Fracture
      1. Uncommon Fracture that requires significant impact to medial ankle or eversion injury with intact deltoid ligament
      2. Medial Malleolus Fracture is most often associated with fibula Fracture (Bimalleolar Fracture)
    2. Distal Tibial Physis Fractures
      1. Distal Tibia Fractures are common Epiphyseal Fractures in Children
      2. Type 2 Salter-Harris Fracture
        1. Associated with external rotation, twisting injury in childhood sports
        2. Evaluate for associated transverse fibula Fracture
      3. Type 4 Salter Harris Fracture (Triplane Fracture)
        1. Rare, axial loading injuries (e.g. fall)
        2. High Risk Fractures for complication
  2. Anterior Ankle Fractures
    1. Anterior Tibial Physis Fracture (Type 3 Salter-Harris Fracture, Tillaux Fracture)
      1. Avulsion Fracture of anterior tibial tubercle (anterolateral distal tibia)
      2. Results from ankle abduction and external rotation with intact anterior-inferior tibiofibular ligament
      3. Growth impaired if Fracture not reduced to <2 mm
    2. Talar Neck Fracture (Pilot's Fracture)
      1. Historically seen in pilots involved in plane crash in which foot was forcefully pushed backward
      2. Primarily due to motor vehicle including motorcycle accidents
      3. Hawkins Classification 1-4 (dislocation seen in class 2-4)
      4. Osteonecrosis complicates Talar Neck Fractures in 21-58% of cases (esp. with higher Hawkins Class)
    3. Talar Dome Fracture
      1. Mechanism is typically inversion injury (e.g. Ankle Sprain) and may be misdiagnosed as Ankle Sprain
      2. Lateral Talar Dome Fractures
        1. Nearly always due to Trauma
        2. Tenderness at point anterior to the lateral malleolus (anterior-lateral talar dome)
      3. Medial talar dome
        1. May be atraumatic in some cases
        2. Tenderness at point posterior to the medial malleolus (posterior-medial talar dome)
  3. Lateral Ankle Fractures
    1. Distal Fibula Fracture or Lateral Malleolus Fracture (see Weber Classification below)
      1. Most common Ankle Fracture type (accounts for 55% of Ankle Fractures)
      2. Mechanisms include inversion, twisting (spiral Fracture) or direct blow to the lateral malleolus (transverse Fracture)
    2. Talus Fracture (Snowboarder's Fracture)
      1. Lateral Process Fracture of Talus caused by ankle dorsiflexion with foot inversion (unique injury to Snowboarding)
      2. Missed on 40-50% of Ankle XRays (confirmed on CT Ankle)
      3. Often initially misdiagnosed as Lateral Ankle Sprain
      4. Findings include significant swelling at lateral talus
      5. Delayed diagnosis risks malunion or nonunion, and subtalar degenerative Arthritis
  4. Whole Ankle Fractures
    1. Pilon Fracture
      1. Talus forced proximally and splitting apart the syndesmosis between the tibia and fibula
      2. Results from high energy Trauma, or in the elderly, by low energy or rotational Trauma
      3. Associated with complicated Fracture patterns requiring CT Ankle
      4. Risk for Compartment Syndrome
    2. Trimalleolar Fracture
      1. Accounts for 7-12% of Ankle Fractures
      2. Results from high impact injury (e.g. Collision Sports) or from fall
      3. Fracture of Medial Malleolus, Posterior Malleolus (posterior edge of tibia) and Lateral Malleolus
      4. Complex, unstable Fracture
      5. Surgical ORIF is often required unless well approximated closed reduction

V. Classification: Fibula Fracture (Weber Classification)

  1. Weber A (stable)
    1. Transverse fibula avulsion Fracture below syndesmosis and below talar dome and joint line
    2. May be associated with a medial malleolus Fracture (oblique or vertical) or medial deltoid ligament tear
    3. Syndesmosis intact, and nearly always stable (esp. if no medial malleolus Fracture)
  2. Weber B (may be unstable)
    1. Fracture at the level of the talar dome
    2. Oblique fibula Fracture (spiral Fracture) at syndesmosis
    3. May be accompanied by medial deltoid ligament tear or medial malleolus transverse avulsion Fracture
    4. May tear anterior tibiofibular ligament (lateral ankle)
    5. Syndesmosis is typically intact, but Fracture is often unstable (esp. if medial Deltoid ligament rupture)
  3. Weber C (unstable)
    1. Lateral malleolus fibula Fracture, above ATF ligament
    2. Associated with Tibiofibular syndesmotic ligament rupture
    3. May be associated with transverse medial malleolus Fracture or medial Deltoid ligament rupture
  4. Images
    1. ankleFractureWeberABC.jpg
  5. References
    1. Hughes (1979) Clin Orthop Relat Res (138):111-9 +PMID:445892 [PubMed]

VI. Exam

  1. See Ankle Exam
  2. See Knee Exam
  3. See Foot Exam
  4. Key exam points
    1. Key Tenet of all Musculoskeletal Exams: Neurovascular, Joint above, joint below, skin and compartments
    2. Thorough neurovascular exam of the foot
    3. Include exam and palpation of proximal tibia and fibula, and foot

VII. Signs and Symptoms

  1. Local tenderness and pain
  2. Swelling
  3. Ecchymosis
  4. Inability to bear weight
  5. Significant deformity if dislocation present

VIII. Differential Diagnosis

  1. Pott's Fracture of the Ankle
  2. Talar Dome Fracture
  3. Posterior Talar Fracture
  4. Lateral Talar Fracture
  5. Ankle Sprain

IX. Associated Conditions

  1. See Calcaneal Fracture
  2. Fifth Metatarsal Fracture
    1. Jones Fracture
      1. Transverse Fracture at base of fifth Metatarsal at metaphysis due to inversion injury
    2. Pseudo-Jones Fracture
      1. Avulsion Fracture of base of fifth Metatarsal (at peroneus brevis insertion)
      2. Results from plantar flexion and inversion injury
  3. Maisonneuve Fracture
    1. Results from internal rotation of leg on fixed foot
    2. Findings include proximal fibula tenderness in addition to significant ankle injury
    3. Multiple associated distal injuries at ankle
      1. Deltoid ligament rupture
      2. Anterior and posterior talofibular ligament rupture
      3. Syndesmotic ligament rupture
    4. Proximal injuries at knee
      1. Proximal tibiofibular ligament rupture or
      2. Proximal Fibula Fracture
    5. Risks
      1. Unstable Fracture if syndesmotic instability (consult orthopedics)
      2. Motor weakness due to superficial fibular nerve compression
      3. Associated with Compartment Syndrome
      4. Frequently missed on initial evaluation (always evaluate proximally in Ankle Fractures)

X. Imaging

  1. Ankle XRay (AP, Lateral and Mortise View)
    1. See Ankle XRay
    2. Consider Foot XRay, Tibia-Fibula XRay or dedicated Calcaneus XRays
    3. Instability findings
      1. Widening of ankle mortise (Weber C and some Weber B Fractures)
        1. Consistent with unstable Ankle Fracture
        2. Consider performing on stress view in unimalleolar Fractures
      2. Lateral talus displacement at rest, on gravity stress or external rotation (Weber B)
        1. Suggests Deltoid ligament rupture (and unstable Fracture)
        2. Consistent with a "bimalleolar-equivalent" Fracture
          1. Unimalleolar Fracture with ligament instability at opposite malleolus
  2. CT Ankle
    1. Consider in suspected occult Ankle Fracture or to be better define Fracture seen on XRay
  3. MRI foot indications
    1. Suspected Calcaneal Stress Fracture or Navicular Stress Fracture

XI. Management: Initial emergency department evaluation

  1. General measures
    1. Rest, elevation and non-weight bearing
    2. Ice to area up to every 20 min per hour while awake for first 72 hours
  2. Reduce Ankle Fracture-dislocation
    1. Do not delay reduction of dislocated ankle and displaced farcture
      1. Risk of tissue ischemia (including skin necrosis) and articular surface injury
    2. Perform reduction under Hematoma Block or Procedural Sedation
    3. Apply inline traction while Splinting (Quigley maneuver pulls great toe up and medially)
    4. Most Fractures requiring reduction will need surgical management
  3. Initial Splinting
    1. CAM Boot for stable distal Fractures
    2. Sugar tong splint combined with posterior splint for unstable Fractures (esp. reduced Fractures)
      1. Extend to long leg splint in proximal Fracture (e.g. Maisonneuve Fracture)
  4. Emergent orthopedic evaluation and surgery
    1. Open Fracture
    2. Neurovascular compromise
    3. Non-reducible Fracture
  5. Routine surgical management
    1. Indications
      1. Weber C Fracture
      2. Weber A Fracture with medial malleolus Fracture
      3. Trimalleolar Fracture
      4. Maisonneuve Fracture
      5. Weber B Fracture with instability (refer all Weber B Fractures to orthopedics for reevaluation)
        1. Findings suggestive of instability
          1. Ankle mortise wide
          2. Lateral talus displacement on gravity stress or external rotation
        2. Findings suggestive of stability (stable Fracture in 98% of cases if both criteria present)
          1. Posterior displacement of of distal Fracture fragment <2mm (on lateral XRay)
          2. Only two Fracture fragments
          3. Nortunen (2017) J Bone Joint Surg Am 99(6): 482-7 +PMID:28291180 [PubMed]
    2. Initial management
      1. Immobilize in fiberglass or plaster splint (sugar tong with or without posterior splint)
      2. Non-weight bearing and elevation
    3. Follow-up re-evaluation orthopedics for possible surgical management
      1. Weber B Fractures are indeterminate for surgical management until Stress Imaging
      2. ORIF may be performed in first day prior significant swelling, but otherwise after 6 days
  6. Conservative Management
    1. Weber A Fracture without medial medial malleolus Fracture
      1. CAM Boot or hard-soled shoe
      2. Weight bearing as tolerated
      3. Fracture line may persist on xray despite asymptomatic patient (no management required)
    2. Distal fibular chip Fracture (ATF or CF Ligament avulsion Fracture)
      1. Treat with Ankle Sprain Management

XII. Management: Lateral Ankle Fracture (Weber-based protocol)

  1. Surgical management (ORIF) Indications (disrupted ankle mortise)
    1. Weber A Fracture WITH medial maleolus vertical Fracture
    2. Weber B Fracture with instability
      1. Ankle mortise wide
      2. Lateral talus displacement on gravity stress or external rotation
    3. Weber C Fracture (all)
    4. Trimalleolar Fracture
    5. Maisonneuve Fracture
  2. Non-surgical, conservate management
    1. Weber B Fracture with stable ankle mortise
    2. Weber A Fracture (stable Fracture)

XIII. Complications

  1. Ankle Osteoarthritis
    1. Osteoarthritis is more likely if poorly aligned ankle mortise or talus position
    2. Fracture management shoul ensure smooth articular surface of ankle

XIV. Prognosis

  1. Stable Fractures treated with non-operative, conservative therapy
    1. Return to baseline activity within 6-8 weeks is common
  2. Unstable Fractures requiring surgical intervention
    1. Weight bearing after surgery is often delayed up to 12-16 weeks
    2. Return to full functional capacity may require up to 2 years
  3. References
    1. Smeeing (2018) Eur J Trauma Emerg Surg 46(1): 121-30 [PubMed]

XV. References

  1. Courtney and Shannon (2020) Crit Dec Emerg Med 34(5): 14-5
  2. Kiel and Desvaristes (2019) Crit Dec Emerg Med 33(7): 16-7
  3. Orman and Ramadorai in Herbert (2017) EM:Rap 17(1): 7-9
  4. Titchner, Morris and Davenport (2021) Crit Dec Emerg Med 35(5): 17-23

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