Talar Neck Fractures

Question 1

Epidemiology

Answer 1

most common fracture of talus ( 50%)

Question 2

Mechanism

Answer 2

• a high-energy injury
• is forced dorsiflexion with axial load

Question 3

Articulation

Answer 3

• 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
• posterior process consist of medial and lateral tubercles separated by groove for FHL

Question 4

Blood supply

Answer 4

talar neck supplied by three sources

1. posterior tibial artery (dominant supply)
2. anterior tibial artery
3. perforating peroneal artery via artery of tarsal sinus

Question 5

Classification

Answer 5

Question 6

Imaging

Answer 6

• Radiographs
  
  • recommended views
    
    • AP
    • lateral
    • Canale view
      
      • best view to demonstrate talar neck fractures
      • technique is maximum equinus, 15 degrees pronated, xray 75 degrees cephalad from horizontal
• CT scan
  
  • best study to determine degree of displacement, comminution and articular congruity
  • CT scan also will assess for ipsilateral foot injuries (up to 89% incidence)

Question 7

Canale view

Answer 7

Canale view

• best view to demonstrate talar neck fractures
• technique is maximum equinus, 15 degrees pronated, xray 75 degrees cephalad from horizontal

Question 8

Nonoperative

Answer 8

• emergent reduction in ER
  
  • indications
    
    • all cases require emergent closed reduction in ER
• short leg cast for 8-12 weeks (NWB for first 6 weeks)
  
  • indications
    
    • nondisplaced fractures (Hawkins I)
  • CT to confirm nondisplaced without articular stepoff

Question 9

Operative

Answer 9

open reduction and internal fixation

• indications
  
  • all displaced fractures (Hawkins II-IV)
• techniques
  
  • extruded talus should be replaced and treated with ORIF
• complications
  
  • post-traumatic arthritis
  • mal-union
  • non-union
  • infection
  • wound dehiscence

Question 10

how do you preform surgery?

Answer 10

• approach
  
  • two approaches recommended
    
    • visualize medial and lateral neck to assess reduction
    • typical areas of comminution are dorsal and medial
  • anteromedial
    
    • between tibialis anterior and posterior tibialis
    • preserve soft tissue attachments, especially deep deltoid ligament (blood supply)
    • medial malleolar osteotomy to preserve deltoid ligament
  • anterolateral
    
    • between tibia and fibula proximally, in line with 4th ray
    • elevate extensor digitorum brevis and remove debris from subtalar joint
• technique
  
  • anatomic reduction essential
  • variety of implants used including mini and small fragment screws, cannulated screws and mini fragment plates
  • medial and lateral lag screws may be used in simple fracture patterns
  • consider mini fragment plates in comminuted fractures to buttress against varus collapse
• postoperative
  
  • non-weight-bearing for 10-12 weeks

Question 11

Complications

Answer 11

• Osteonecrosis
  
  • 31% overall (including all subtypes)
  • radiographs
    
    • hawkins sign
      
      • subchondral lucency best seen on mortise Xray at 6-8 weeks
      • indicates intact vascularity with resorption of subchondral bone
    • associated with talar neck comminution and open fractures
• Posttraumatic arthritis
  
  • subtalar arthritis (50%) is the most common complication
  • tibiotalar arthritis (33%)
• Varus malunion (25-30%)
  
  • can be prevented by anatomic reduction
  • treatment includes medial opening wedge osteotomy of talar neck
  • leads to
    
    • decreased subtalar eversion
      
      • decreased motion with locked midfoot and hindfoot
    • weight bearing on the lateral border of the foot