Does involvement of the anterior syndesmosis affect the functional outcome of acute ligamentous ankle injuries?

Purpose: To compare patient-reported outcomes between acute ligamentous ankle injuries 1) without anterior syndesmosis involvement and 2) with anterior syndesmosis involvement (without clinical instability). Study design: Prospective cohort study. Methods: Between September 2016 and December 2020 all athletes (≥ 18) with an acute ankle injury presenting within 7 days post-injury were screened for eligibility. Athletes were excluded if imaging demonstrated a frank fracture or 3T magnetic resonance imaging could not be acquired within 10 days post-injury. Athletes with unstable syndesmosis injuries or athletes who underwent surgery within 1-year post-injury were excluded. Athletes underwent criteria-based rehabilitation and functional outcomes (Karlsson & Peterson score, Foot and Ankle Outcome Score) were assessed at 6 weeks, 6 months, and 1 year. Results: A total of 94 athletes were included. In 28 athletes (30 %) the anterior syndesmosis was injured. In the first six weeks post-injury, median Karlsson & Peterson score improved from 37 (interquartile range 20.5–49) to 80 (interquartile range 70–90) for the group without involvement versus 35 (interquartile range 25–62) to 82 (interquartile range 72–87) for the group with involvement. FAOS sports improved similarly in both groups. No statistically significant between group differences in functional outcome scores were observed at six weeks, six months and 1 year follow-up. Conclusions: In athletes, acute ligamentous ankle injuries with involvement of the anterior syndesmosis ligament (without clinical instability) are not associated with worse functional outcome at 6 weeks, 6 months, and 1-year post-injury compared to acute ligamentous ankle injuries without involvement.