Transcript Perilunate dislocations Dr. P Kruger

Perilunate
dislocations
Dr. P Kruger
General points
• Can be missed easily
• If left untreated lead to high
incidence of long term functional
disability and chronic pain.
• Perilunate dislocations more
common than lunate dislocations
Mechanism of injury
• Hyperdorsiflexion of wrist
• Hyperextension of wrist
• Usually due to high-energy trauma to
the wrist e.g.
- Fall on outstretched hand
- Motor vehicle and motorcycle
accidents
Diagnosis
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Clinical history
Index of suspicion
Examination of hand
X-Ray + other views if indicated
- closed fist ulnar/radial stress
view
- Scaphoid view
- Supination oblique view
- Carpal tunnel view
Management
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ABC
Splint immobilization or backslab
Analgesia
Elevation
IV antibiotics if open fracture
Refer to hand surgeon
- Closed reduction or ORIF
Stages
• 4 stages
• Originally described by Mayfield.
• Each stage represent a sequential
intercarpal injury.
• Can be associated with specific
bony fractures including the radial
styloid, scaphoid, capitate and
triquetrum.
Stage 1 – Scapholunate dissociation
Widening of scapholunate
joint > 2mm on PA view
Terry Thomas sign
Stage II - Capitate
dislocation
• Dislocation or subluxation of
capitate
• Best seen on lateral view
• Lunate remains in normal position
in relation to distal radius, capitate
is dislocated. ( usually dorsally )
• Scaphoid fracture or subluxation
can also occur.
Stage III – Triquetrum
dislocation
• Perilunate dislocation
• Triquetral and scaphoid malrotation
• Lunate remains normal position, other
carpal bones dislocated posteriorly
• May be associated with triquetrial
fracture
Stage IV - Lunate
dislocation
• Most severe of carpal instabilities
• Most commonly associated with
trans scaphoid fracture
• Produces volar dislocation and
forward rotation of lunate. Capitate
drops into place vacated by lunate
• Lunate appears triangular in shape
on frontal view ( piece of pie sign )
• Spilled tea cup sign
Spilled tea cup
sign
Triangular shaped
lunate
Volar lunate dislocation
X-ray Examples
Normal X-rays
Stage I
Volar perilunate
dislocation
Dorsal perilunate dislocation
Lunate dislocation
Perilunate dislocation