Dorsal intercalated segment instability

Dorsal intercalated segment instability (DISI) is a deformity of the wrist where the lunate bone angulates to the dorsal side of the hand.

Causes

The main cause of DISI is wrist trauma, with or without a fracture:

• Scaphoid fracture: bony DISI
• Distal radius fracture: compensatory DISI
• Malunion of radius fracture: adaptive DISI
• Scapholunate ligament instability: ligamentous DISI

References