Delayed stabilisation of dynamically unstable syndesmotic injuries results in worse functional outcomes

Purpose Patients with primarily ligamentous injuries of the distal tibiofibular joint comprise up to 12% of all ankle sprains. Patients frequently present late after a syndesmosis injury and delayed treatment potentially leads to pain, prolonged disability and arthritis in the long term. This study aimed to assess clinical outcomes in patients who required syndesmosis fixation in the presence of arthroscopically proven instability, the hypothesis being that a delay to treatment would be associated with worse function. Method A retrospective cohort study was performed of patients with dynamic instability requiring fixation between the years of 2010-2016. The procedures were performed by two foot and ankle fellowship trained orthopaedic surgeons, over three hospital sites. Patients were classified into three groups based on the time since injury to surgery, acute syndesmotic injury (< 6 weeks), sub-acute (6 weeks-6 months) and chronic syndesmotic injury (> 6 months). Functional scores were retrospectively collected using the Foot and Ankle Outcome Score (FAOS). Results Compared to patients with acute injuries, those with chronic injuries had significantly lower FAOS subscales (p < 0.001), with the greatest difference in quality of life (- 20.7, 95% CI - 31.6 to - 9.8, p = 0.012). There was a mean follow-up of 4.3 years. Although the average FAOS subscales in those with sub-acute injuries were lower than in those with acute injuries, the difference was not statistically significant. Conclusion The results of this study suggest that delayed surgical stabilisation (> 6 months) is associated with significantly worse clinical function, and thus timely identification and early referral of those patients with potentially unstable syndesmotic injuries is recommended.