Cystic avascular necrosis of the triquetrum.

Carpal bones are rarely affected by avascular necrosis (AVN) in the absence of fractures. The lunate is the most frequently affected carpal bone, followed by the scaphoid and the capitate. The triquetrum is rarely affected by AVN. We report a case of multiple cystic changes in the triquetrum in a patient with a history of trauma. He was treated by below elbow Colles plaster cast for 3 months, with no improvement. Cystic changes resulted from irreversible AVN of the triquetrum. This is the first case to be reported in the literature with cystic AVN changes in the triquetrum.