Abstract

Background: Lateral ligament ankle sprains are the single most common sports injury.

Objective: To determine the functional outcome of the ankle joint after a moderate or severe inversion injury, comparing standard treatment with an elastic support bandage against an Aircast ankle brace.

Design: Prospective, randomised controlled trial.

Setting: Two accident and emergency departments.

Method: Fifty patients presenting consecutively were randomised into two equal groups: one group was treated with an elastic support bandage and the other with an Aircast ankle brace. All patients were given a standardised advice sheet referring to rest, ice, compression, and elevation. Patients were reviewed after 48–72 hours, 10 days, and one month.

Primary outcome measure: Ankle joint function assessed at 10 days and one month using the modified Karlsson scoring method (maximum score 90).

Secondary outcome measure: The difference in ankle girth (swelling) and pain score at 10 days.

Results: Seventeen patients in the elastic support bandage group (six defaulted, two excluded) and 18 patients in the Aircast ankle brace group (six defaulted, one excluded) completed the study. There were no significant differences between the two groups at presentation in terms of age (mean 35.3 and 32.6 years respectively), sex, dominant leg, left or right ankle injured, previous injury, time to presentation (median three and four hours respectively), difference in ankle girth (mean 14.5 and 14.3 mm respectively), and pain scores (mean 6.2 and 5.8 respectively). The Karlsson score was significantly higher in the Aircast ankle cast group than in the elastic bandage group at 10 days (mean 50 v 35, p  =  0.028, 95% confidence interval (CI) 1.7 to 27.7) and one month (mean 68 v 55, p  =  0.029, 95% CI 1.4 to 24.8) (Student’s t test). There was no difference between the groups in the secondary outcome measures (swelling, p  =  0.09; pain, p  =  0.07). When hierarchical multiple regression analysis was used to correct for possible baseline confounding factors, the Aircast ankle brace group was significantly associated with higher Karlsson scores at 10 days (p  =  0.009) and one month (p  =  0.024).

Conclusion: The use of an Aircast ankle brace for the treatment of lateral ligament ankle sprains produces a significant improvement in ankle joint function at both 10 days and one month compared with standard management with an elastic support bandage.