gms | German Medical Science

Objectives/Interrogation: There are many operative techniques to treat mallet fracture when it is larger than one-third of the articular surface of the distal interphalangeal (DIP) joint, including extension block pinning or open reduction and internal fixation and the use of a hook plate. The extension block pinning is a useful surgical procedure for the treatment of this fracture. However, its complications are pin tract infection, flexion contracture of DIP joint and delayed union or nonunion. We have reported good outcome of minimally invasive screw fixation (MISF) technique for mallet fracture on 2013 FESSH, which is combined closed reduction of the mallet fragment by an extension block pining with internal fixation with one or two Leibinger screws through dorsal stab skin incision. We retrospectively compared the clinical and radiographic results of extension block pinning with MISF for mallet fractures.

Methods: Forty patients with a mallet fracture involving more than one-third of the articular surface were reviewed. Twenty cases were treated using extension block pinning (EB group) and 20 were treated using MISF technique (MI group). At the final follow-up (average 18 months), extension lag and range of motion of the DIP joint of the affected digit were measured. and the overall clinical outcomes were graded using Crawford's criteria. Complications, including nail deformity and dorsal prominence, were also assessed. The Mann-Whitney's U test was used to determine the significance of intergroup differences for continuous variables.

Results and Conclusions: At the final follow-up, the mean extension lag in MI group was 2.2°, which was significant different from that of the EB group (mean 12.8°; P<0.01). The mean range of motion of DIP joint in MI group was 74.9°, which was significant different from that of the EB group (mean 51.2°; P<0.01). Outcomes, as assessed using Crawford's criteria, were excellent in 12, good in 2, and fair in 6 in the MI group, and excellent in 2, good in 17, and fair in 8 in the EB group. All the fractures had united by 3 months after injury in both groups.

We acknowledge that this is a short-term study of a small series, but patients treated with MISF technique had greater ROM and clinical outcome in the finger than extension block pinning. The current study indicates that adaptation of MISF for mallet fracture may be efficient to minimize soft tissue damage, stabilize the fracture fragment and mobilize the joint at the early stage.