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  • Epidemiology
    • less than 1% of all fractures
    • second most common tarsal fractures after calcaneus fxs
    • talar body fractures
      • account for 13-23% of talus fractures
    • lateral process fractures
      • account for 10.4% of talus fractures
    • talar head fracture
      • least common talus fracture
  • Mechanism
    • talar body
      • injuries often result from high energy trauma, with the hindfoot either in supination or pronation
    • lateral process of talus
      • injuries result from forced dorsiflexion, axial loading, and inversion with external rotation
        • often seen in snowboarders
  • Prognosis
    • lateral process injuries have a favorable outcomes with prompt diagnosis and immediate treatment
  • 3D Anatomy of talus  
  • Talus has no muscular or tendinous attachments
  • Articulation
    • there are 5 articulating surfaces
      • seventy percent of the talus is covered by cartilage
      • inferior surface articulates with posterior facet of calcaneus
    • talar head articulates with
      • navicular bone
      • sustenaculum tali
    • lateral process articulates with
      • posterior facet of calcaneus
      • lateral malleolus of fibula
        • this forms the lateral margin of the talofibular joint
    • posterior process consist of medial and lateral tubercle separated by groove for FHL
  • Blood supply
    • because of limited soft tissue attachments, the talus has a direct extra-osseous blood supply
    • sources include 
      • posterior tibial artery
        • via artery of tarsal canal (most important and main supply)
          • supplies most of talar body
        • via calcaneal braches
          • supplies posterior talus
      • anterior tibial artery
        • supplies head and neck
      • perforating peroneal arteries via artery of tarsal sinus
        • supplies head and neck
      • deltoid artery (located in deep segment of deltoid ligament)
        • supplies body
        • may be only remaining blood supply with a talar neck fracture
  • Anatomic classification
    • Lateral Process Fx 
      • type 1 fractures do not involved the articular surface
      • type 2 fractures involve the subtalar and talofibular joints
      • type 3 fractures have comminution
    • Posterior Process Fx
      • posteromedial tubercle fractures
        • result from an avulsion of the posterior talotibial ligament or posterior deltoid ligament
      • posterolateral tubercle fractures
        • result from an avulsion of the posterior talofibular ligament
    • Talar Head Fx
    • Talar Body Fx
Physical Exam
  • Symptoms
    • pain
      • lateral process fractures often misdiagnosed as ankle sprains
  • Physical exam
    • provocative tests
      • pain aggravated by FHL flexion or extension may be found with a posterolateral tubercle fractures
  • Radiographs
    • recommended views
      • AP and lateral
        • lateral process fractures may be viewed on AP radiographs
      • Canale View 
        • optimal view of talar neck
        • technique
          • maximum equinus
          • 15% pronated
          • Xray 75 degrees cephalad from horizontal
      • careful not to mistake os trigonum (present in up to 50%) for fracture 
      • may be falsely negative in talar lateral process fx
  • CT scan
    • indicated when suspicion is high and radiographs are negative  q q
      • best study for posterior process fx,  lateral process fx, and posteromedial process fx
    • helpful to determine degree of displacement, comminution, and articular congruity
  • MRI
    • can be used to confirm diagnosis when radiographs are negative

Radiographs CT MRI Bone Scan
Lateral Process Fx   
Posterior Process Fx
Talar Head Fx      
Talar Body Fx         
  • Nonoperative
    • SLC for 6 weeks
      • indications
        • nondisplaced (< 2mm) lateral process fractures
        • nondisplaced (< 2mm) posterior process fractures
        • nondisplaced (< 2mm) talar head fractures
        • nondisplaced (< 2mm) talar body fractures
      • technique
        • cast molded to support longitudinal arch
  • Operative
    • ORIF/Kirshner wire Fixation
      • indications
        • displaced (> 2mm) lateral process fractures
        • displaced (> 2mm) talar head fractures
        • displaced (> 2mm) talar body fractures
          • medial, lateral or posterior malleolar osteotomies may be necessary
        • displaced (> 2mm) posteromedial process fractures
          • may require osteotomies of posterior or medial malleoli to adequately reduce the fragments
    • fragment excision
      • indications
        • comminuted lateral process fractures
        • comminuted posterior process fractures
        • nonunions of posterior process fractures
  • ORIF/Kirshner Wires
    • approaches
      • lateral approach
        • for lateral process fractures
        • incision over tarsal sinus, reflect EDB distally
      • posteromedial approach
        • for medial tubercle of posterior process fracture or for entire posterior process fracture that has displaced medially
        • between FDL and neurovascular bundle
      • posterolateral approach
        • for lateral tubercle of posterior process fractures
        • between peroneal tendons and Achilles tendon (protect sural nerve)
        • beware when dissecting medial to FHL tendon (neurovascular bundle lies there)
      • combined lateral and medial approach
        • required for talar body fractures with more than 2 mm of displacement 
  • Fragment excisions
    • incompetence of the lateral talocalcaneal ligament is expected with excision of a 1 cm fragment
      • this is biomechanically tolerated and does not lead to ankle or subtalar joint instability  q
  • AVN 
    • Hawkins sign (lucency) indications revascularization  
      • lack of Hawkins sign with sclerosis is indicative of AVN 
  • Talonavicular arthritis
    • posttraumatic arthritis is common in all of these fractures
    • this can be treated with an arthrodesis of the talonavicular joint
  • Malunion
  • Chronic pain from symptomatic nonunion
    • may have pain up to 2 years after treatment
  • Subtalar arthritis
    • found in 45% of patients with lateral process fractures, treated either non-operatively or operatively

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