Management of hook-negative/external rotation stress-positive syndesmotic injuries in supination-external rotation type IV ankle fractures: a comparison of suture button, screw fixation, and non-fixation

Management of the tibiofibular syndesmosis in supination-external rotation (SER) type IV ankle fractures remains controversial. This study evaluates clinical and radiological outcomes of suture button fixation, screw fixation, and no fixation in patients with a negative Hook test but a positive external rotation (ER) stress test. 145 patients were retrospectively reviewed and allocated into three groups based on syndesmotic management: No-Fixation ( n = 48), Suture Button ( n = 55), and Screw ( n = 42). Primary outcomes included AOFAS, OMAS, and VAS scores over 24 months. Computed tomography (CT) was used to evaluate syndesmotic reduction and rotational alignment at 1 year. At 1 and 3 months postoperatively, both Suture Button and Screw groups demonstrated significantly higher functional scores and lower pain levels compared to the No-Fixation group ( p < 0.05). However, by the 6-month follow-up and through to 2 years, there were no significant differences in AOFAS, OMAS, or VAS scores among the three cohorts. CT analysis at 1 year showed a slight translational widening in the No-Fixation group ( p < 0.05), but rotational parameters remained consistent across all groups ( p > 0.05). Syndesmotic fixation was associated with earlier weight-bearing and faster early recovery, but these early differences were inseparable from the more accelerated rehabilitation protocol permitted by fixation. By 2 years, clinical and rotational outcomes were similar across groups. In Hook-negative/ER-positive SER IV injuries, syndesmotic fixation may support earlier mobilization, but omission of fixation did not compromise long-term function in this cohort.