Epidemiology of Isolated Ankle Dislocations in the United States

CATEGORY: Trauma; Ankle INTRODUCTION/PURPOSE: Isolated ankle dislocations (IADs) are rare type of dislocation associated with significant morbidity. Prompt reduction is indicated to prevent negative sequelae. Considering the potential negative outcomes associated with this injury, we sought to identify populations at increased risk. METHODS: The National Electronic Injury Surveillance System (NEISS) database was queried to identify patients who presented to Emergency Departments (EDs) in the U.S. for IADs between 2001-2019. NEISS codes indicating ankle dislocation as the primary diagnosis were utilized. Population estimates were derived from the U.S. Census Bureau for calculation of incidence in person- years. Chi-square analysis and Wald chi-square tests were performed to assess differences between subgroups. RESULTS: An estimated 52,520 IADs (2,862 per year) were identified among a population at risk of 5,853,993,882 person-years. The estimated incidence of IADs in the general population presenting to EDs was 0.90 per 100,000 person-years. Patients with IADs were most commonly male (61.6%), white (71.9%), and between 15-35 years old (60.1%). Patients aged 15-20 years comprised the highest proportion of IADs (19.6%). Surprisingly, sport-related activities accounted for a minority of injuries (38.2%), with most of these occurring during basketball (47.8%), football (12.9%), and soccer (9.8%). Most IADs were due to non- athletic activity, with falls from stairs (30.8%) and ladders (13.4%), and skateboarding (5.0%) being the most common mechanisms. When comparing injured male and female patients, female patients were older (45.2 vs 32.0 years; P<0.001), more likely to be injured during non-athletic activities (83.9% vs 48.1%; P<0.001), and more likely to be hospitalized after ED visit (27.3% vs 17.6%; P<0.001). CONCLUSION: IADs are extremely rare. They occur most frequently during non-athletic activities in young-to-middle-aged Caucasian men. Although more common in males, females with IADs tend to be older, more likely to be injured during non- athletic activities compared to sports, and more likely to be hospitalized. This suggests that, when IADs do occur in women, they may be at higher risk for negative outcomes.