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Introduction
  • Navicular fractures can be
    • traumatic
      • navicular avulsion fractures
        • mechanism is plantar flexion
      • navicular tuberosity fractures
        • mechanism is eversion with simultaneous contraction of PTT
        • may represent an acute widening/diastasis of an accessory navicular
      • navicular body fractures
        • mechanism is axial loading
    • stress fracture  
      • mechanism of injury is usually due to chronic overuse 
      • often seen in athletes running on hard surfaces
      • also common in baseball players 
      • considered a high risk injury due to risk of AVN
      • most common complications include delayed union and non-union  
Anatomy
  • Articulations
    • navicular bone articulates with
      • cuneiforms
      • cuboid
      • calcaneus
      • talus
  • Biomechanics
    • navicular bone and its articulations play an important role in inversion and eversion biomechanics and motion
Classification
 
Sangeorzan Classification of Navicular Body Fractures
(based on plane of fracture and degree of comminution)
Type I Transverse fracture of dorsal fragment that involves < 50% of bone.
No associated deformity
  
Type II Oblique fracture, usually from dorsal-lateral to plantar-medial.
May have forefoot aDDuction deformity.
 
Type IIII Central or lateral comminution.
ABDuction deformity.
  
 
Presentation
  • Symptoms
    • vague midfoot pain and swelling
  • Physical exam
    • midfoot swelling
    • tenderness to palpation of midfoot
    • usually full ROM of ankle and subtalar joint
Imaging
  • Radiographs
    • may be difficult to see and are often missed
    • oblique 45 degree radiograph 
      • best to visualize tuberosity fractures
  • CT
    • more sensitive to identify fracture than radiographs 
  • MRI
    • will show signal intensity on T2 image due to inflammation 
Treatment of Stress Fractures
  • Nonoperative
    • cast immobilization with no weight bearing  
      • indications
        • any navicular stress fracture, regardless of type, can be initially treated with cast immobilization and nonweight bearing for 6-8 weeks with high rates of success 
  • Operative
    • open reduction and internal fixation
      • indications
        • high level athletes
        • nonunion of navicular stress fracture
        • failure of cast immobilization and non weight bearing
Treatment of Traumatic Fractures
  • Nonoperative
    • cast immobilization with no weight bearing
      • indications
        • acute avulsion fractures 
        • most tuberosity fractures
        • minimally displaced Type I and II navicular body fractures
  • Operative
    • fragment excision
      • indications
        • avulsion fractures that failed to improve with nonoperative modalities
        • tuberosity fractures that went on to symptomatic nonunion
    • open reduction and internal fixation
      • indications
        • avulsion fractures involving > 25% of articular surface
        • tuberosity fractures with > 5mm diastasis or large intra-articular fragment
        • displaced or intra-articular Type I and II navicular body fractures 
      • technique
        • medial approach
          • used for Type I and II navicular body fractures
    • ORIF followed by external fixation VS. primary fusion
      • indications
        • Type III navicular body fractures 
      • technique
        • must maintain lateral column length
 

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