Intrinsic predictors of lateral ankle sprain in adolescent dancers: a prospective cohort study.

OBJECTIVE

To identify intrinsic predictors of lateral ankle sprain.

DESIGN

Prospective cohort study.

SETTING

A performing arts secondary school and a dance school.

PARTICIPANTS

One hundred fifteen adolescent dancers (94 female and 21 male) entered the study. One ankle of each dancer was randomly assigned to a test group (n = 114), and the other was assigned to a validation group (n = 112).

PREDICTORS: Eighteen measures, including age, dance history, previous ankle sprain, ankle and foot laxity and range of motion, and balance from test ankles were entered into a backwards stepwise Cox regression model. The model generated with the test group was used to predict ankle sprains in the validation group.

MAIN OUTCOME MEASURE: Time to first lateral ankle sprain.

RESULTS

An increased risk of sprain in the test group was predicted by younger age [hazard ratio (HR) = 0.65, 95% CI 0.45-0.94], previous sprain of the contralateral ankle (HR = 3.76, CI 1.24-11.40), increased passive inversion range (HR = 1.06, CI 1.00-1.12), and inability to balance on demipointe (HR = 3.75, CI 1.02-13.73). Of these predictors, only previous sprain of the contralateral ankle significantly predicted ankle sprain in the validation group (HR = 3.90, CI 1.49-10.22). The predictive accuracy of this variable was not strong (positive likelihood ratio of 2.01 and negative likelihood ratio of 0.45).

CONCLUSION

A history of previous lateral ankle sprain is associated with an increase in the risk of future sprain of the contralateral ankle.