Carpal fractures

Background

• Scaphoid fractures account for 70% of all carpal fractures
• Ulnar nerve damage associated with fractures of hamate or pisiform
• 50% of pisiform fx associated with injury to distal radius or other carpal bone
• If bone fragment seen posterior to carpus on lateral, very likely triquetrum fx

Diagnosis

• Mechamism of injury
  • Hyperextension (FOOSH)
    • Scaphoid, lunate, triquetrum, or pisiform fractures
    • Consider oblique views
  • Hyperflexion
    • Triquetrum fracture
  • Axial loading
    • of the wrist: scaphoid fx, scapholunate dissociation
    • thumb: trapezium fx
    • index: trapezoid fx
  • Direct blow to palmar surface
    • Pisiform or hamate fractures
• Specific Bone Fx
  • Scaphoid
    • Pain in the snuffbox (especially with ulnar deviation)
    • Grip strength reduced
    • Often associated with perilunate dislocation
  • Lunate
    • Pain aggravated by wrist motion or gripping
    • Pain with axial loading of the 3rd digit
    • Often associated with other injuries
  • Triquetrum
    • TTP just distal to the ulnar styloidPain on the ulnar aspect of the wrist
  • Pisiform
    • Pain/swelling at the palmar and ulnar aspects of the wrist
    • TTP over the hypothenar eminence
  • Hamate
    • Sudden wrist pain when a swinging motion has been interrupted
    • TTP over hypothenar eminence
    • 4th, 5th digit paresthesia if fx involves ulnar nerve
  • Capitate
    • Pain/swelling on dorsum of hand
    • Rarely fractured in isolation
  • Trapezoid
    • Point tenderness just proximal to 2nd metacarpal base
  • Trapezium
    • Pain/weakness with making "OK" sign or touching thumb to tip of 5th digit
    • Significant discomfort
    • Minimal swelling

Imaging

• Checklist

1. Palmar tilt of the radius is present on the lateral view
2. Radial articular surface lies distal to the ulna
3. Dorsal surface of the distal radius is smooth
4. Waist of the scaphoid is intact
5. Capitate sits in the concavity of the lunate
6. Intercarpal joints are no more than 2mm wide; adjacent surfaces are parallel

• PA
  • Evaluate zone of vulnerability
• Lateral
  • Evaluate scapholunate angle (should be between 40o and 60o)
• Oblique
• Also consider:
  • PA with maximal ulnar deviation ("Scaphoid View")
    • Scaphoid fx
  • Carpal tunnel view
    • Hamate hook fx
    • Trapezium fx
    • Pisiform Fx
  • PA clenched fist view
    • Consider for scapholunate instability (space >2mm suggests ligamentous disruption)
  • CT
    • Trapezoid fx

Treatment

• Scaphoid Fx
  • Thumb-spica spint (or preferably a cast) until repeat xrays performed at 10 days
• Lunate Fx
  • Double sugar tong or long-arm thumb spica splint
  • May lead to osteonecrosis if not recognized and treated
• Triquetrum Fx
  • Volar splint w/ wrist in slight dorsiflexion and the MCP free
• Pisiform Fx
  • Volar or dorsal splint
• Hamate Fx
  • Volar splint
• Capitate Fx
  • Sugar-tong or short arm thumb spica splint
• Trapezoid Fx
  • Volar splint
• Trapezium Fx
  • Short arm thumb-spica
• Dislocations
  • Scapholunate
    • Volar splint, referral within 1 week
  • Lunate/perilunate
    • Volar spint, immediate reduction

Disposition

• Scaphoid Fx
  • Always refer to a hand surgeon b/c may lead to osteonecrosis if not recognized/treated
• Lunate Fx
  • Always refer to a hand surgeon b/c may lead to osteonecrosis if not recognized/treated
• Triquetrum Fx
  • Refer for displacment >1mm
• Pisiform Fx
  • Tend to do well with casting; refer for casting if unable to obtain in the ED
• Hamate Fx
  • Refer for dislocation, pts who need to return to actvitiy ASAP
• Capitate Fx
  • Always refer to a hand surgeon b/c may lead to osteonecrosis if not recognized/treated
• Trapezoid Fx
  • Refer for comminution or dislocation
• Trapezium Fx
  • Refer for displacement >2mm, intraarticular fx w/ >1mm incongruity, comminuted fx

• Lunate/perilunate dislocation
  • Consult hand surgeon for immediate reduction(very difficult to reduce)

Source

UpToDate, Accident & Emergency Radiology, Harwood-Nuss