scaphoid fractures

see also:

• orthopaedics in the ED
• Ballarat ED Clinical Practice Guidelines for Mx of scaphoid fracture (pdf)
• http://foam4gp.com/2013/11/15/foam4gp-map-scaphoid-fractures-thumbing-through-the-research/
• http://lifeinthefastlane.com/scaphoid-fractures-the-ed-perspective/
• UK patient information sheet - scaphoid fracture
• BMJ 2013: Investigation of suspected scaphoid fractures

• 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

• 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

• sens. ~70%

• poor inter-operator reliability coefficient

• unreliable

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

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

• 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⁾

• 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.

• 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