Concomitant Syndesmotic Instability and Medial Ankle Instability Are Risk Factors for Unsatisfactory Outcomes in Patients With Chronic Ankle Instability

PurposeTo determine whether concomitant chronic syndesmotic injury or chronic medial ankle instability is associated with unsatisfactory outcomes in patients with chronic lateral ankle instability (CAI).MethodsWe conducted a retrospective review of prospectively collected data from 276 male military patients with CAI who had undergone a modified Broström procedure between May 2007 and March 2010 and had been followed up for a mean of 26.7 months (range, 22 to 41 months). We evaluated clinical outcomes using American Orthopaedic Foot & Ankle Society ankle-hindfoot, visual analog scale, and ankle functional satisfactory scale scores. Possible associations with concomitant instability were reconstructed and investigated using the Pearson correlation coefficient and multivariate logistic regression analysis.ResultsOf the 236 patients with satisfactory outcomes, 19 (8%) had medial ankle instability and 13 (6%) had syndesmotic instability; in contrast, of the 40 patients with unsatisfactory outcomes, 14 (35%) had medial ankle instability and 12 (30%) had syndesmotic instability. The mean American Orthopaedic Foot & Ankle Society scores for patients with satisfactory and unsatisfactory outcomes increased from 68.1 to 92.8 (P < .001) and from 65.9 to 76.8 (P < .001), respectively. The mean visual analog scale scores for the groups with satisfactory and unsatisfactory outcomes decreased from 5.8 to 2.1 (P < .001) and from 6.2 to 4.8 (P < .001), respectively. The mean ankle satisfaction score was 27.8 for patients with satisfactory outcomes and 18.7 for those with unsatisfactory outcomes (P < .001). Multivariate logistic regression analysis showed a 4-fold higher risk of dissatisfaction (95% confidence interval [CI], 0.81 to 20.07; P = .0880) with CAI and syndesmotic instability, a 3.8-fold higher risk (95% CI, 0.96 to 15.07; P = .0576) with CAI and medial ankle instability, and an 11.7-fold higher risk (95% CI, 2.60 to 52.70; P = .0014) with CAI and both syndesmotic and medial ankle instability.ConclusionsChronic syndesmotic instability and chronic medial ankle instability are significantly associated with unsatisfactory outcomes in patients with CAI.Level of EvidenceLevel IV, therapeutic case series.