Chondral thinning at the ulnolunate articulation, subchondral cysts/erosions and marrow edema within the proximal aspect of the lunate(ulnar side), significant thinning and possible tear of membranous component of triangular fibrocartilage. Complimentary radiograph done in clenched fist position showed positive ulnar variance(not shown). Findings are consistent with ulnar impaction sydnrome.

The differentiation of this entity with avascular necrosis of lunate is important. In ulnar impaction syndrome, erosions/abnormality is seen in ulnar side of lunate and it is associated with positive ulnar variance. On the other hand, in avascular necrosis of lunate, abnormality is seen in radial side of lunate and it is associated with negative ulnar variance.