Modified extension-block K-wire fixation technique for the treatment of bony mallet finger.

This article describes the treatment of a bony mallet finger deformity using 2 extension-block Kirschner wires (K-wires) with a transarticular K-wire fixation technique for precise alignment of the terminal extensor tendon-bone relationship and effective immobilization of the distal interphalangeal joint. Twenty-nine patients (33 fingers) with a bony mallet finger deformity and fracture fragment involving more than one-third of the articular surface were treated surgically. The fracture fragment was fixed and the mallet finger deformity was corrected in all patients using modified extension-block K-wires (2 dorsal extension-block pins) with a transarticular K-wire (volar side pin) fixation technique. Active motion of the proximal interphalangeal and metacarpophalangeal joints was not restricted. The wires are removed in the clinic 6 weeks postoperatively when the bridging trabeculae were observed in the radiographs, and immobilization in a stock splint was continued for an additional 2 weeks. According to Crawford's evaluation criteria, there were 24 (73%) excellent, 7 (21%) good, and 2 (6%) fair results. Three patients showed radiological signs of mild degenerative changes, which did not limit their daily activities. Nail ridging occurred in 3 cases (9%), which disappeared after an average of 6 months with normal growth, and mild scarring at the dorsal pin site occurred in 2 cases (6%). Modified extension-block K-wires with a transarticular K-wire fixation technique is an acceptable alternative treatment modality for the management of bony mallet finger deformities with or without subluxation of the distal phalanx.