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

Carpal Bone	Mechanism of Injury	Examination	ED Management
Scaphoid	FOOSH	Snuffbox tenderness; pain w/ radial deviation/flexion	Short arm, thumb spica, in dorsiflexion w/ radial deviation
Triquetrum	1. Avulsion fracture: twisting of hand against resistance or hyperextension 2. Body fracture: direct trauma	Tenderness at dorsum of the wrist, distal to the ulnar styloid	Short arm, sugar tong splint
Lunate	FOOSH	Tenderness at shallow indentation of the mid-dorsum of wrist, ulnar and distal to Lister tubercle	Short arm, thumb spica splint
Trapezium	Direct blow to thumb; force to wrist while dorsiflexed and radially deviated	Painful thumb movement and weak pinch strength; snuffbox tenderness	Short arm thumb spica splint
Pisiform	Fall directed on hypothenar eminence	Tender pisiform, prominent at the base of hypothenar eminence	Short arm, volar splint in 30 degrees flexion and ulnar deviation
Hamate	Interrupted swing of golf club, bat, or racquet	Tenderness at hook of hamate, just distal and radial to the pisiform	Short arm, volar wrist splint with 4th and 5th metacarpal joints in flexion
Capitate	Forceful dorsiflexion of the hand with radial impact	Tenderness over capitate just proximal to the third metacarpal	Short arm, volar wrist splint
Trapezoid		Tenderness over radial aspect of base of index metacarpal	Short arm thumb spica splint

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 styloid
  • Pain 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

• See Wrist Bones
• Checklist

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

• PA
  • Evaluate Zone of Vulnerability
• Lateral
  • Evaluate scapholunate angle (should be between 40-60deg)
• 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

Source

• UpToDate
• Accident & Emergency Radiology

See Also

• Wrist Bones