Background: A variety of surgical techniques for treating mallet fracture finger has been reported with different outcomes and complications. However, the optimal procedure remains controversial. This study describes surgical outcomes of mallet fractures of the finger with distal phalanx treated by modified pull-out wire fixation with Kirschner wire (K-wire) stabilization of the DIP joint in hyperextension.
Materials and methods: 30 patients who had mallet fracture finger injuries (Doyle's classification type IVC) with DIP joint subluxation between January 2009 and January 2015 were included in this study. The mean age was 28 years (range 18-50 years), and the mean duration of followup was 8 months (range 6-12 months). Outcome assessments included the skin necrosis, wire tract infection, bony union, and extension lag. We measured the pinch strength test at 8 weeks and 12 weeks postoperatively and graded the clinical results using Crawford's criteria.
Results: All fractures united after surgery. There was no iatrogenic fracture fragmentation, marginal skin necrosis, wire tract infection, and nail deformity. The mean extension lag was 1.8° (range 0°-17°) through goniometer, 24 of 30 patients had 0° of extension lag. The pinch strength measured at 8 weeks and 12 weeks was 79% and improved to 91%, respectively, compared with uninjured opposite finger. According to Crawford's criteria, 24 patients were classified as excellent, 3 were good, and 3 were fair. No poor result in this study.
Conclusion: Our modified pull-out wire fixation over a button and K-wire stabilization of DIP joint in hyperextension is a reliable surgical method for treating acute mallet fracture finger and DIP joint volar subluxation.
Keywords: Kirschner wire; Phalanges of fingers; distal phalanx; joint instability; mallet fracture finger; pull-out wire; tendon injuries.