Evolution of arthritis of the wrist.

Degenerative arthritis of the wrist follows very specific patterns from onset to terminal severe bone and joint destruction. About 95% of them occur as periscaphoid area problems: SLAC (scapholunate advanced collapse pattern) wrist (55%), triscaphe arthritis (26%), and a combination of the two (14%). In SLAC wrist, the repeating sequence of degenerative change is based on and caused by articular alignment problems between the scaphoid and the radius. Changes then progress between the capitate and the lunate that are secondary to carpal collapse. In triscaphe arthritis, the degenerative change is limited to between the trapezium, trapezoid, and distal scaphoid. SLAC procedure (fusion of the capitate, lunate, hamate, and triquetrum along with silastic scaphoid implant) for SLAC wrists and triscaphe arthrodesis (fusion of the scaphoid, trapezium, and trapezoid) for triscaphe arthritis, are designed to make maximum use of undamaged structures and to maintain full-power, painless, mobile human wrists.