Season 9 Case 17

History: Wrist Pain

Answer: Trans-scaphoid Perilunate dislocation

-lunate still "normal" position while other carpal bones dislocate dorsally ++ assoc scaphoid fx! (count the proximal row!)

Perilunate Dislocation:

Mechanism: high-energy trauma (MVA) or FOOSH (fall on outstretched hand)

Injury: torn radioscaphoid, scapholunate & lunotriquetral ligaments.

Look for the scaphoid fx!

Imaging:

-Frontal: lunate appears triangular ("pie sign") & overlaps capitate

-Lateral: lunate "normal"w other carpal bones dislocated (typically dorsal). Somtimes slight palmar tilt from the capitate trying to get back to normal -capitate not sitting in "cup" of lunate

Perilunate Dislocation is often confused with LUNATE dislocation.

Although there are similarities, just remember what is actually dislocating.

Is the lunate dislocated?

Yes=LUNATE dislocation

NO,but other bones dislocated? = PERI-lunate dislocation