A 30 year old male presents to your ED, complaining of wrist pain following a fall while playing roller hockey. He denies wearing protective gear. On exam he has point tenderness over the dorsal aspect of his R wrist. You order an plain film:
What is your diagnosis?
Scapholunate dissociation (SLD) refers to a disruption in the Scapholunate Interosseus Ligament (SLIL).
SLD can be seen alone, but also frequently with distal radial fractures and scaphoid fractures. It is the most common form of carpal instability, but frequently missed. Diagnosis can be made on plain film. Typically, separation between the scapula and lunate of >3mm raises suspicion. This is often referred to as the “Terry Thomas” sign.
Terry Thomas was “an English comedian and character actor during the 1950s and ’60s. He often portrayed disreputable members of the upper classes, especially cads, toffs and bounders, using his distinctive voice; his costume and props tended to include a monocle, waistcoat and cigarette holder.” (1) He also happened to have a very pronouced gap between his two upper central incisors.
This is also commonly referred to as the “David Letterman” sign, to keep up with the times.
These patients should be placed in a thumb spica and given urgent referral to a hand specialist or orthopedic surgeon.
(1) Credit: Wikipedia