Palmar Midcarpal Instability.

Abstract

Palmar midcarpal instability is a rare condition. Patients usually report pain and clunking while engaged in wrist motion, especially with radial to ulnar deviation, or just performing the act of grasping. X-ray shows volar intercarpal segment instability pattern, in which the lunate shows volar flexion on lateral view. Motion radiographs or fluoroscopic movies show volar subluxation of the capitate with respect to the lunate in flexion or ulnar deviation and sudden reduction with radial deviation or extension. The cause of palmar midcarpal instability is still unknown, while the dorsal intercarpal ligament and/or dorsal radiocarpal ligament may be responsible for this rare condition. Also, general joint laxity can be hidden in this condition. Treatments of midcarpal instability are quite difficult in nature. Normally, patients underwent midcarpal fusion, such as “scaphocapitate fusion” or “lunocapitate fusion.” Some undertook arthroscopic approach and reconstruction of the sagged ulnar carpal rows, using tendon graft.