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Talus Fracture (other than neck)

Topic updated on 11/08/15 4:10pm
Introduction
  • 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
Anatomy
  • 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
Classification
  • 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
Imaging
  • 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         
 
Treatment
  • 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
Technique
  • ORIF/Kirshner Wires
    • approaches
      • lateral approach
        • for lateral process fractures
      • posterolateral approach
        • for posterior process fractures
      • 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
Complications
  • 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
  • Nonunion
  • Subtalar arthritis
    • found in 45% of patients with lateral process fractures, treated either non-operatively or operatively

 

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Qbank (2 Questions)

TAG
(OBQ10.154) Excision of the 1 centimeter talar fragment shown in Figure A would lead to complete incompetence of which of the following structures? Topic Review Topic
FIGURES: A          

1. Bifurcate ligament
2. Inferior peroneal retinaculum
3. Lateral talocalcaneal ligament
4. Arcuate ligament
5. Posterior talofibular ligament

PREFERRED RESPONSE ▶
TAG
(OBQ04.123) A 34-year-old male has persistent anterolateral ankle pain after a snowboarding injury 1 week ago and is unable to bear weight. Ankle radiographs are negative for fracture. What is the next step in management? Topic Review Topic

1. MR arthrogram of the ankle
2. Bone scan
3. CT scan
4. Diagnostic injection
5. Repeat radiographs

PREFERRED RESPONSE ▶




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