Capitohamate axial carpal instability of the wrist

Cooney and colleagues coined the term axial-loading dislocation to describe injuries of the carpus where the derangement occurred parallel to the long axis of the forearm [2]. Axial dislocation of the carpus typically occurs after high-energy dorsopalmar compression (crush mechanism), resulting in longitudinal disruption of the carpal arch. The disruption results in the carpus splitting into two axial columns, one remaining normally aligned to the radius and the other becoming unstable and displacing in a radial or ulnar direction. These two patterns are called axial-radial and axial-ulnar fracture-dislocations, respectively [4, 5] (Fig. 21.1).