BACKGROUND: Extension-block pinning is a popular treatment for mallet fractures, but it is associated with several pitfalls. Ofnote, transfixation Kirschner wires used to fix the distal interphalangeal (DIP) joint may cause iatrogenic nail bed injury, bone fragmentrotation, chondral damage, or osteoarthritis. The objective of this study was to determine whether a transfixation pin was necessaryfor extension-block pinning in the treatment of bony mallet fracture.METHODS: Patients were treated with a pin-orthosis extension-block technique if they had been diagnosed with a type IVB malletfracture according to Doyle’s classification. Radiological outcomes were evaluated based on postoperative X-ray results, and functionaloutcomes were evaluated using Crawford’s criteria.RESULTS: Thirteen patients (9 males and 4 females) with a mean age of 26 years were included. The mean time between the injuryand surgery was 3.3 days, and the mean follow-up period was 8.2 months (range: 4–12 months). Radiographic bone union was achievedin all patients within an average of 5.1 weeks (range: 5–6 weeks). At the final follow-up, the DIP joint had an average degree of flexionof 76.1° (range: 65°–80°) and an average extension deficit of 3.84° (range: 0°–15°). According to Crawford’s criteria, 8 patients hadexcellent results, 4 patients had good results, and 1 patient had a fair result. No patient reported pain at the final follow-up.CONCLUSION: Satisfactory clinical and radiological outcomes were obtained with the pin-orthosis extension-block technique.Future prospective and randomized studies are justified to confirm the efficacy of this technique.