Wrist Arthroscopy and Carpal Instability

The wrist is composed of a series of complex articulations between the carpal bones, radius, and ulna. It can be artificially separated into the radiocarpal, midcarpal, and distal radioulnar joints. Functionally, the carpal bones can be divided into the proximal (scaphoid, lunate, and triquetrum) and distal (trapezium, trapezoid, capitate, and hamate) rows.1 The pisiform is a sesamoid bone within the substance of the flexor carpi ulnaris tendon, and while the pisotriquetral joint can become unstable, it is typically not addressed arthroscopically. Stability of the wrist is dependent upon congruent articular anatomy and ligamentous attachments. The carpal ligaments have been divided into extrinsic and intrinsic ligaments.2–5 The extrinsic ligaments span the radiocarpal joint originating on the radius or ulna and inserting on the carpal bones of the proximal and/or distal rows. The intrinsic ligaments connect adjacent carpal bones and thereby separate intercarpal compartments.