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fracture_scaphoid

scaphoid fractures

introduction

  • fracture of the scaphoid is a critical diagnosis to be made early as missed diagnoses or occult fractures result in non-union in ~12% and risk of avascular necrosis (particularly for proximal fractures)
  • it is very rare under age 8 years

diagnosis of scaphoid fracture

clinical tests

  • anatomical snuff box (ASB) tenderness
    • sens. ~100% spec variable
  • axial loading on thumb (hold thumb and push proximally)
  • scaphoid tubercle tenderness (palpate base of thenar eminence)
    • when combined with ASB and axial loading: sens ~100%, spec high

initial plain Xray with scaphoid views

  • sens. ~70%

repeat Xray in 10-14 days looking for signs of fracture healing

  • poor inter-operator reliability coefficient

ultrasound

  • unreliable

initial CT scan

  • sens. > 72%, spec. > 80% (may not be as good in children aged under 14yrs)
  • radiation dose = ~25 CXRs

initial MRI scan

  • negative predictive value, sensitivity and specificity, approaching 100%

nuclear med scan

  • early scans in the 1st few days have false positive rates due to traumatic synovitis
  • very good sens/spec if after 5 days but expensive, and higher radition doses1)

general Mx of suspected scaphoid fractures in the ED

  • NB. the scaphoid bone is not usually fully visible on Xrays in children under 8 years of age, and in this group, scaphoid fracture is exceedingly rare and thus the information below primarily applies to adolescents and adults.
  • All cases of suspected scaphoid fractures require scaphoid x-ray views in addition to Anterior/Posterior (AP) and lateral films.
  • If x-ray shows fracture:
    • place in scaphoid plaster, arrange POP check 24 hours post-application in the Emergency Department, and review at 1 - 2 weeks - usually in a fracture clinic.
    • all patients should be given plaster instructions eg. Vic DHS - Fractures and plaster care (pdf)
  • If x-ray shows no fracture:
    • if there is swelling and/or severe tenderness in the anatomical snuff box, immobilise in scaphoid plaster and arrange repeat x-ray and review in 10 days.
    • if tenderness is mild, apply supportive bandage (eg. Tubigrip) and arrange repeat x-ray and review in 7- 10 days.
    • If at 10 days there is improvement in symptoms and no evidence of fracture on the review X-ray, then it is unlikely that there is a scaphoid fracture.
    • If the diagnosis needs to be known earlier then a bone scan or CT may be performed 2 days after the injury.

Mx of proven fracture

  • potential indications for surgery:
    • displacement > 1mm
    • proximal fractures given that the alternative may be 6 months in plaster?
    • clearly visible fractures?
    • fractures with lunar tilt
    • non-union
    • not willing to wear a cast for 6-12 weeks
  • POP cast immobilisation (most advise including the thumb):
    • 6-8 weeks for distal 1/3rd fracture
    • 8-12 weeks for middle 1/3rd fracture
    • 12-23 weeks for proximal 1/3rd fractures
fracture_scaphoid.txt · Last modified: 2015/12/17 22:51 by wh