Scaphoid Fractures

• Anatomy of Hand:

  • scaphoid is part of the proximal row of carpals

  
• Clinical Presentation:

  • mechanism:
  • extreme extension and radial deviation
  • FOOSH
  • road traffic collision
  • incidence:
  • 90% of all carpal fractures
  • most common in men 15 to 30 years old
• Examination:

  • tenderness of the anatomical snuffbox in the cardinal sign
  • Highest probability of fracture anatomical snuffbox and scaphoid tubercle combined with Compression thumb (sensitivity 100%, specificity 74%) – clinical assessment more important than x-ray
  • scaphoid fracture are commonly missed fractures
  • Cutaneous branch of radial nerve root runs directly over anatomical snuffbox, therefore often discomfort

  
• Imaging:

  • equal to or less than 48% false negative
  • improved accuracy with a scaphoid series
  • 4 to 7 xrays
  • MRI
  • CT
• Radiographers report:

  • fracture
  • location
  • involvement of articular surfaces
  • displacement
  • humpback deformity - angulation between the proximal and distal aspects or the parts of the bone that have been fractured through that
  • alignment
  • scapholunate interval - gap between scaphoid and lunate can indicate concurrent ligament injury
  • lunate dislocation - can indicate concurrent ligament injury
  • associated fractures (e.g. colles fractures)
  • evidence of avascular necrosis if the fracture is subacute
• Classification of Scaphoid Fractures:

  • scaphoid fractures can be classified by:
  • location
  • orientation
  • stability
• Classification of Scaphoid Fractures:

  • location:
  • tubercle
  • distal pole - 10%
  • waist - most commonly fractured - 70%
  • proximal pole - 20%

  A) tubercle

  B) distal pole

  C) waist

  D) proximal pole

  
• Classification of Scaphoid Fractures:

  • orientation:
  • transverse - fracture going straight across the bone
  • horizontal oblique - fracture is straight, but also angled horizontally
  • vertical oblique - fracture is straight, but also angled vertically - indicates a longer healing time
• Classification of Scaphoid Fractures:

  • stability:
  • important in determining conservative or surgical intervention
• Classification of Scaphoid Fractures:

  • stability classifications:
  • stable fractures:
  • nondisplaced - fracture throughout the whole bone, the two sides of the fracture are still close to each other
  • incomplete - fracture is not throughout the whole bone, so two sides stay close to each other and less likelihood of avascular necrosis
• Classification of Scaphoid Fractures:

  • stability classifications:
  • stable fractures:
  • nondisplaced - fracture throughout the whole bone, the two sides of the fracture are still close to each other
  • incomplete - fracture is not throughout the whole bone, so two sides stay close to each other and less likelihood of avascular necrosis

  A) nondisplaced

  B) incomplete

  
• Classification of Scaphoid Fractures:

  • stability classifications:
  • unstable fractures:
  • displaced - two sides of the bone aren't lined up together, can lead to malunion and avascular necrosis
  • angulated - humpback deformity where two parts of the bone have cracked apart and there no good connection between those two parts
  • ligamentous instability - damaged ligaments around the scaphoid, meaning the scaphoid moves around more, so the two sides arent close together to promote healing

  A) displaced

  B) angulated

  C) ligamentous instability

  
• Classification of Scaphoid Fractures:

  • stability classification subcategories:
  • static instability:
  • visible on xray
  • dynamic instability:
  • appears normal on xray
  • becomes abnormal in certain positions/movements
• Management of Scaphoid Fractures:

  • If you clinically suspect a Scaphoid Fracture, treat it as a scaphoid fracture until proven otherwise
  • Immediate treatment = 9% delayed union
  • Delayed treatment (more than 4/52) = 36% delayed union
• Management of Scaphoid Fractures:

  • conservative management - for clinically suspected or stable fractures:
  • immobilisation
  • analgesia
  • monitoring via the fracture clinic
  • surgical management - for unstable fracture:
  • internal fixation
  • internal fixation + bone graft (non-union)
• Complications of Scaphoid Fractures:

  • factors affecting prognosis for scaphoid fractures:
  • blood supply - majority of blood supply usually enters the scaphoid distally, so if theres a fracture more proximal to where the blood supply is coming in, there is an increased likelihood for the loss of blood supply and potential avascular necrosis on that proximal segment
  • location
  • orientation
  • displacement
  • instability
• Avascular Necrosis:

  • occurs in 15 to 30 % of scaphoid fractures
  • mainly occurs in proximal fractures
  • results in collapse and fragmentation of the necrotic bone
• Non-union / Malunion:

  • major complication of scaphoid fractures
  • where the fracture doesnt heal properly or heals at an angle, causing:
  • instability
  • OA
  • SNAC - scaphoid nonunion advanced collapse
  • proximal scaphoid segment stays attached to the lunate, but distal scaphoid segment rotates away into flexion - leads to OA changes
  • SLAC - scapholunate advanced collapse
  • chronic dissociation between the scaphoid and lunate
  • if theres been ligament damage and it hasnt repaired, theres a big gap between the scaphoid and lunate - causing OA changes