Extension Type Locked Metacarpophalangeal Joint of the Little Finger due to Hyperextension Injury

Abstract

The extension type locked metacarpophalangeal joint of the little finger is an extremely rare condition characterized by loss of flexion with little or no loss of extension. The most common cause for locking is entrapment of a strap of the ruptured palmar plate. We treated a locked metacarpophalangeal joint of the little finger due to a hyperextension injury. The mechanism of locking was a torn part of the palmar ligament that forcefully rides across the prominence of the radial condyle of the metacarpal bone together with the accessory collateral ligament. These dislocated parts of the ligament formed a constricting bundle that prevented closed reduction. Locking was released successfully by an open reduction using the dorsal approach of the metacarpophalangeal joint without complication.