24 year-old male presents following fall from a scaffolding and complains of wrist pain. Diagnosis?
Answer: Perilunate dislocation
Perilunate dislocations usually occur following high-energy trauma (e.g., fall from a height); the mechanism is usually wrist hyperextension, ulnar deviation, and carpal supination.
Tenderness is palpated along the dorsum of the wrist; specifically distal to the lister tubercle along the scapholunate ligament; injuries may be associated with scaphoid fracture
Paresthesias may also occur along the median nerve distribution with up to 25% of cases developing carpal tunnel syndrome.
Treatment options include closed reduction and casting or open reduction and ligamentous repair with internal fixation.
The figure below illustrates the differences between lunate and perilunate dislocations.
References
Lunate and Perilunate Dislocations. Kannikeswaran, N & Sethuraman, U.
http://www.radiologyassistant.nl/en/42a29ec06b9e8 (diagram)
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