Image diagnosis: Perilunate and lunate dislocations.

Perilunate Dislocation Anterior-posterior (AP) view (Figure 1) demonstrates the distal and proximal carpal rows overlapping, as well as a complete radial styloid fracture. Lateral view (Figures 2 and 3) demonstrates dorsal dislocation of the capitate, whereas the lunate remains articulated with the radius. More often seen in young men in their teens to twenties, rather than children or the elderly, it is a high-energy mechanism that causes wrist hyperextension resulting in perilunate dislocation. As seen here, it is more common to see an associated fracture of a carpal bone, such as the scaphoid, or an associated radial or ulnar styloid fracture, rather than a dislocation alone. An estimated 16% to 25% of perilunate dislocations are missed on initial exam, resulting in increased morbidity eventually requiring open reduction with fixation and sometimes salvage repair. Image Diagnosis: Perilunate and Lunate Dislocations