Figure: Frontal radiograph of the wrist shows marked degenerative change (joint space narrowing and subchondral sclerosis) of the radioscaphoid joint (yellow arrowheads), widening of the scapholunate space, and proximal migration of the capitate (C) filling in this widened space. The radiolunate joint (red arrowheads) is spared by degeneration.
- Insufficiency of scapholunate and radioscapholunate ligaments, causing increased mobility of the scaphoid on the radius
- Abnormal load to the capitate upon lunate, then capitate enters the widened scapholunate joint space and approximates distal radius
- Three stages: the third stage is called "SLAC wrist", in which the capitates enters the scapholunate gap and approaches the distal radius. The radiocarpal joint at lunate is spared by degeneration.