Pin orthosis extension block pinning versus conservative treatment for doyle type 4B mallet fractures

Although numerous treatment options have been reported for mallet fractures, a universally accepted gold-standard approach has not yet been established. The purpose of this study was to compare the clinical and radiographic outcomes of the pin-orthosis extension-block pinning technique (PO-EBPT) with those of conventional conservative treatment in patients with Doyle type 4B mallet fractures.

This study included 62 patients with Doyle type 4B mallet fractures involving 20-50% of the distal interphalangeal (DIP) joint articular surface, treated between March 2022 and April 2024. Patients were randomized into two groups: Group 1 (n = 33) underwent PO-EBPT, whereas Group 2 (n = 29) received conservative treatment with splint immobilization. Outcome measures included DIP joint extension lag, range of motion, fracture union, complication rates and functional outcomes according to the Crawford criteria. Follow-up evaluations were performed at 2, 4 and 6 weeks and at 3, 6 and 12 months.

A total of 62 patients were analyzed (33 PO-EBPT; 29 conservative). No statistically significant differences were observed between the groups with respect to sex, affected side, injured finger, or complication rates (p = 0.461, p = 0.658, p = 0.763 and p = 0.165, respectively). However, the PO-EBPT group demonstrated significantly improved DIP joint extension lag (4.5 ± 7.8° vs. 12.2 ± 10.4°, p = 0.002) and flexion range (88.5 ± 4.4° vs. 86.0 ± 5.7°, p = 0.039). According to the Crawford criteria, functional outcomes were also significantly superior in the PO-EBPT group (p = 0.02).

PO-EBPT yielded superior functional outcomes compared with conservative treatment in patients with Doyle type 4B mallet fractures, as demonstrated by reduced extension lag, improved DIP joint flexion and higher rates of excellent Crawford scores.