Definitions
- SNAC: scaphoid non-union advanced collapse
- SLAC: scapholunate advanced collapse
Both describe progressive degenerative collapse patterns of the wrist.
SNAC wrist
Occurs after chronic scaphoid non-union. Degeneration typically begins at the radial styloid and distal scaphoid articulation, then progresses.
SLAC wrist
Occurs after chronic scapholunate ligament injury and DISI deformity. Degeneration follows a staged pattern beginning at the radioscaphoid joint.
Clinical features
- Pain
- Reduced grip strength
- Stiffness
- Mechanical symptoms
Management
- Non-operative treatment for mild symptoms
- Radial styloidectomy in selected early cases
- Proximal row carpectomy or four-corner fusion in appropriate patients
- Total wrist arthrodesis for salvage
Diagram
