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Carpal dislocations

Dr Frank Gaillard et al.

Carpal dislocations represent a spectrum of perilunate instability relating to ligament injuries. Instability has been divided into 4 stages. ^1-2

stage I: scapholunate dissociation (rotatory subluxation of the scaphoid)
- disruption of scapholunate ligament with resultant Terry Thomas sign
- exacerbated in clenched fist views
stage II: perilunate dislocation
- the lunate remains normally aligned with the distal radius, and the remaining carpal bones are dislocated (almost always dorsally)
- capitolunate joint is disrupted, and the lunate projects through the Space of Poirier
- 60% are associated with scaphoid fractures
stage III: midcarpal dislocation
- triquetrolunate interosseous ligament disruption or
- triquetral fracture
stage IV: lunate dislocation
- dorsal radiolunate ligament injury
- dislocation of the lunate in a palmar direction