Comparison of extension block pinning technique versus pin orthosis-extension block pinning technique for acute mallet fractures: a prospective randomized clinical trial

Introduction The extension block pinning technique (EBPT) is a popular surgical treatment for mallet fractures; however, it has several drawbacks. The purpose of this randomized clinical trial was to compare EBPT to the pin orthosis-extension block pinning method (PO-EBPT) in the treatment of mallet fractures involving more than one-third of the joint surface but without primary joint dislocation. Materials and methods Sixty-five patients with mallet fractures were randomized into two groups between June 2017 and January 2020: Group I (33 patients) was treated with EBPT and group II (32 patients) was treated with PO-EBPT. Five patients were lost to follow up due to lack of follow-up and death. There were no significant differences in the clinical and demographic characteristics of both groups. Patients were evaluated according to fracture union, extension lag, distal interphalangeal (DIP) joint range of motion, Crawford's criteria, and complication rates. The patients were followed-up post-operatively at 2 weeks, 6 weeks, 3 months, 6 months, 1 year, and annually thereafter. Results A total of 60 patients were randomized into two groups: one (30 patients) was treated with EBPT and the second (30 patients) with PO-EBPT. There were no significant differences between the two groups in terms of fracture union and active DIP joint flexion (P = 0.743 and P = 0.059, respectively). The mean extension lag of the DIP joint in the EBPT group was significantly greater than the PO-EBPT group (10 degrees +/- 9.47 degrees vs. 4.17 degrees +/- 7.2 degrees, P = 0.009). According to the Crawford criteria, the PO-EBPT group showed significantly better outcomes (P = 0.005). The complication rates were similar between groups (P = 0.45). Conclusion In comparison to the EBPT technique, the group of patients operated with PO-EBPT had superior clinical outcomes and less loss of extension at the DIP joint according to the Crawford's criteria.