The Epidemiology of High Ankle Sprains in National Collegiate Athletic Association Sports

Ankle sprain has been studied in athletic cohorts, but little is known of its epidemiology in the general population. A longitudinal, prospective epidemiological database was used to determine the incidence and demographic risk factors for ankle sprains presenting to emergency departments in the United States. It was our hypothesis that ankle sprain is influenced by sex, race, age, and involvement in athletics. The National Electronic Injury Surveillance System (NEISS) was queried for all ankle sprain injuries presenting to emergency departments between 2002 and 2006. Incidence rate ratios were then calculated with respect to age, sex, and race. During the study period, an estimated 3,140,132 ankle sprains occurred among an at-risk population of 1,461,379,599 person-years for an incidence rate of 2.15 per 1000 person-years in the United States. The peak incidence of ankle sprain occurred between fifteen and nineteen years of age (7.2 per 1000 person-years). Males, compared with females, did not demonstrate an overall increased incidence rate ratio for ankle sprain (incidence rate ratio, 1.04; 95% confidence interval, 1.00 to 1.09). However, males between fifteen and twenty-four years old had a substantially higher incidence of ankle sprain than their female counterparts (incidence rate ratio, 1.53; 95% confidence interval, 1.41 to 1.66), whereas females over thirty years old had a higher incidence compared with their male counterparts (incidence rate ratio, 2.03; 95% confidence interval, 1.65 to 2.65). Compared with the Hispanic race, the black and white races were associated with substantially higher rates of ankle sprain (incidence rate ratio, 3.55 [95% confidence interval, 1.01 to 6.09] and 2.49 [95% confidence interval, 1.01 to 3.97], respectively). Nearly half of all ankle sprains (49.3%) occurred during athletic activity, with basketball (41.1%), football (9.3%), and soccer (7.9%) being associated with the highest percentage of ankle sprains during athletics. An age of ten to nineteen years old is associated with higher rates of ankle sprain. Males between fifteen and twenty-four years old have higher rates of ankle sprain than their female counterparts, whereas females over thirty years old have higher rates than their male counterparts. Half of all ankle sprains occur during athletic activity.

Ankle sprains are a common injury in collegiate sports. Few studies have examined the epidemiology of individual ligament injuries, specifically the lateral ligament complex (LLC) of the ankle.

Twenty-five fresh-frozen cadaveric specimens were used to evaluate the role of the syndesmotic ligaments when the ankle is loaded with external rotation torque. An apparatus was constructed that allowed pure external-rotation torque to be applied through the ankle with the foot in neutral flexion. The apparatus provided solid fixation of the tibia while allowing free movement of the fibula in all planes. The syndesmotic ligaments were incrementally sectioned, and direct measurements of anatomical diastasis were made. Mortise and lateral radiographs were made at each increment under both loaded (5.0 newton-meters) and unloaded conditions. After all structures of the syndesmosis had been divided, the syndesmosis was reduced and was repaired with one or two screws. The strength of the repair was measured with incremental increases in torque of 1.0 newton-meter. The radiographs were measured by three independent observers in a blind fashion. In order to evaluate intraobserver error, each observer was randomly given forty radiographs to reinterpret. Diastasis and rotation were found to be related to the amount of injury of the ligament (p < 0.0001). After the entire syndesmosis had been divided, application of a 5.0-newton-meter torque resulted in a mean diastasis of 7.3 millimeters. The subsequent repair of the anterior tibiofibular ligament with suture failed at a mean of 2.0 newton-meters (range, 1.0 to 6.0 newton-meters) of torque. Repair with two screws was found to be stronger than repair with one, with the first construct failing at a mean of 11.0 newton-meters (range, 5.0 to 15.0 newton-meters) and the second, at a mean of 6.2 newton-meters (range, 2.0 to 10.0 newton-meters) (p = 0.0005). Failure of the screw fixation was not associated with the maximum previous diastasis (p = 0.13). Measurements of anatomical diastasis were compared with measurements made on the mortise and lateral radiographs. Measurements on the stress mortise radiographs had a weak correlation with diastasis (r = 0.41, p < 0.0001). However, measurements on the stress lateral radiographs had a higher correlation (r = 0.81, p < 0.0001). Additionally, interobserver correlation was significantly higher for the measurements on the lateral radiographs (r = 0.87, p < 0.0001) than for those on the mortise radiographs (r = 0.56, p < 0.0001). Intraobserver correlation for the three observers was poor with regard to the measurements on the mortise radiographs (r = 0.12, 0.42, and 0.25). The respective correlations for the measurements on the lateral radiographs were r = 0.81, 0.90, and 0.89.(ABSTRACT TRUNCATED AT 400 WORDS)