Predictors Of Recurrent Sprains In Individuals With Chronic Ankle Instability

Objective: In sports,the ankle sprain is one of the most common injuries.In a general clinical population,73% of patients reported ongoing symptoms 18 months after an ankle sprain.Chronic ankle instability symptoms of pain,recurrent ankle sprains and subjective feelings of instability persist beyond 3 years after injury.The risk of re-injuring an ankle is the most frequently concerned problem of CAI patients.Although orthotic devices are acceptable treatment options to prevent the recurrence of ankle sprain,the unknown reason also should be explored and identified.Methods: A sample of 92 chronic ankle instability individuals was recruited.Potential predictors of recurrent sprain were measured including: demographic measures(age,sex,height and weight),number of previous sprain,exercise frequency,rehabilitation condition,perceived ankle instability(Cumberland Ankle Instability Tool),passive and positive range of ankle motion(plantar flexion,dorsiflexion,inversion,eversion and flexion,first metatarsophalangeal extension),number of foot lift test,Star Excursion Balance Test and side-hop test time.Participants were followed up and the occurrence of ankle sprains was recorded over 12 months.Results: Ninety-nine participants completed the 12-month follow-up;26participants sustained an ankle sprain.11 variables met the criterion of potential predictors.Excepting 2 collinear variables,the combination of rest 9 predictors including: man,more exercise,more previous sprains,smaller passive inversion range of motion,larger foot lift number between ankles,lower Cumberland Ankle Instability Tool score between ankles,smaller fist metatarsophalangeal active extension range of motion,better Star Excursion Balance Test in posteromedial direction and longer side-hop time between ankles correctly classified 83.5%participants of ankle sprain occurrence(χ2=36.16,p<0.001).The regression model provided a sensitivity of 75%,a specificity of 87.3%,a positive predictive value of72% and a negative predictive value of 88.9%.The strongest independent predictors were lower Cumberland Ankle Instability Tool score between ankles(odds ratio(OR)=4.29,95% confidence interval(CI)=1.31 to 14.09),larger foot lift number between ankles(OR=5.16,95%CI=1.53 to 17.41),smaller passive inversion range of motion(OR=3.24,95%CI=1.00 to 10.46)and bigger previous sprain number(OR=3.57,95%CI=1.14 to 11.13).Conclusion: Lower Cumberland Ankle Instability Tool score between ankles,larger foot lift number between ankles,smaller passive inversion range of motion and bigger previous sprain number were the only independent predictors of recurrent sprains in the CAI individuals with perceive instability.The combination of man,more exercise,smaller fist metatarsophalangeal active extension range of motion,better Star Excursion Balance Test in posteromedial direction and longer side-hop time between ankles increased the predictive power.These findings could form the basis for clinic intervention targeted at reducing recurrent sprains in CAI individuals with perceive instability.