Incidence and predictors of syndesmotic injuries in ankle fractures: a cross-sectional study correlating radiographic assessment with intraoperative findings

Background: Syndesmotic injuries are clinically significant ankle injuries that may lead to chronic instability and functional impairment when inadequately managed. While literature suggests these injuries occur in 10-20% of ankle fractures, their true incidence remains poorly characterized. This study aimed to determine the incidence of syndesmotic injuries in ankle fractures and evaluate the diagnostic accuracy of radiographic assessment compared to intraoperative findings. Methods: This 18-month cross-sectional study conducted at a tertiary care center in Pune, India included 49 patients with ankle fractures requiring surgical intervention. Standardized radiographic evaluation was performed to assess syndesmotic parameters (tibiofibular clear space, tibiofibular overlap, and medial clear space). Fractures were classified using the Lauge-Hansen system, and intraoperative assessment was conducted using the Hook test as the reference standard. Statistical analysis included calculation of diagnostic accuracy metrics and multivariate logistic regression to identify independent predictors of syndesmotic injuries. Results: Syndesmotic injuries were identified in 16 patients (32.7%, 95% CI: 19.9%-47.0%), with highest prevalence in Pronation-External Rotation fractures (46.7%) and those resulting from road traffic accidents (44.4%). Radiographic assessment demonstrated good diagnostic performance (sensitivity 87.5%, specificity 81.8%) compared to intraoperative findings. Multivariate analysis identified three independent predictors of syndesmotic injury: Pronation-External Rotation fracture pattern (OR 3.82, p=0.006), road traffic accident mechanism (OR 2.96, p=0.026), and tibiofibular clear space >6 mm (OR 8.35, p<0.001). Patients with syndesmotic injuries demonstrated significantly worse immediate post-operative pain scores (p<0.001) and functional outcomes (p<0.001). Conclusions: Syndesmotic injuries are more common in ankle fractures than previously reported, particularly in high-energy trauma and specific fracture patterns. While systematic radiographic evaluation provides valuable diagnostic information, intraoperative assessment remains essential for definitive diagnosis. These findings emphasize the importance of maintaining a high index of suspicion for syndesmotic injuries in high-risk scenarios to optimize patient outcomes.