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Scapholunate dissociation
From WikEM
Contents
Background
- Caused by rupture of scapholunate ligament
- Most commonly injured ligament of the wrist
- Injury most commonly occurs from FOOSH
Clinical Features
- Pain/swelling on radial side of wrist
- "Clicking" sensation with wrist movement
Evaluation
Imaging
- A grip compression view or wrist in ulnar deviation may be necessary in addition to PA/lateral views
- Any of the following signs may be seen:
- Widening of the scapholunate joint space >3mm
- Know as Terry-Thomas sign (or David Letterman sign)
- Rotary subluxation of the scaphoid
- Lateral view: Scapholunate angle >60 degrees
- PA view: Cortical ring sign (circular cortex of the bone is more prominent)
- Dorsal intercalated segment instability
- Dorsal angulation of lunate relative to radius resulting in capitolunate angle > 20°
- Seen as loss of the normal collinear arrangement of the capitate, lunate, and radius
- Widening of the scapholunate joint space >3mm
Differential Diagnosis
Carpal Dislocations
- Scapholunate dissociation
- Perilunate and lunate dislocations
Carpal fractures
- Scaphoid fracture
- Triquetrum fracture
- Lunate fracture
- Trapezium fracture
- Pisiform fracture
- Hamate fracture
- Capitate fracture
- Trapezoid fracture
Management
- Radial gutter splint or forearm volar splint
- Ortho referral
Disposition
- Generally outpatient follow-up
