Management for Bony Mallet Thumb with a Single Extension Blocking Kirschner Wire

Mallet finger injury is defined by disruption of the terminal extensor tendon distal-to-distal interphalangeal (DIP) joint. While in the fingers, it is a relatively common injury, it is a rarely encountered entity when involving the thumb. Various conservative and operative treatment strategies have been reported for the management of mallet thumb with no consensus by clinicians.

We present the case of a 27-year-old right hand dominant man with a left bony mallet thumb injury that occurred while playing hurling. Hurling is traditional Irish sport that is one of the fastest field games in the world, involving the use of a wooden Hurley and ball. Clinically, there was loss of active extension at the DIP joint of the non-dominant thumb with radiographs revealing an avulsion fracture involving more than one-third of the articular surface at the base of the distal phalanx. Closed reduction and percutaneous fixation using a single extension block Kirschner wire was performed without a transfixion wire across the DIP joint. Four months postoperatively, the patient had regained that good functional dexterity was able to return to playing hurling.

A single K-wire technique may be beneficial with theoretical reduction of chance of iatrogenic nail bed, bone fragment rotation, chondral damage, and bone injury. To the best of our knowledge, no previous reports of its application to bony mallet thumb have been described.