Functional Movement Assessments To Evaluate Dynamic Postural Control In Persons With Chronic Ankle Instability

Abstract

More than 700,000 people sprain their ankles daily, with chronic ankle instability (CAI) occurring in as many as 70% of these individuals. Few research studies have examined the relationship between Functional Movement Screen™ (FMS) and dynamic postural stability in persons with CAI. PURPOSE: To identify differences among measures of dynamic postural stability, FMS-lower extremity scores, and active range of motion (AROM) in those with and without CAI. A secondary purpose was to identify risk factors that predispose individuals to CAI. METHODS: 23 volunteers (12 women, 11 men; age, 22.3 + 2.1 yrs) completed all aspects of this study. We subsequently created 7 triads using a 2:1 ratio, triple matching participants without a history of ankle injury on sex, age, and BMI category with those with CAI. Outcome measures included FMS™ composite score (FMS-CS); FMS™ lower extremity subscore (FMS-LE); Athlete Single Leg Stability Test (ASLST); dorsiflexion, plantar flexion, inversion, and eversion AROM; and Foot and Ankle Disability Index-Sport (FADI-S) score. We used 1-way and 2-way ANOVAs to identify differences between the CASE and CONTROL groups, and the involved and uninvolved limbs of the participants with CAI (p < 0.05). We used binary logistic regression to calculate odds ratios to determine the extent postulated risk factors increased the risk of developing CAI. RESULTS: ANOVA results indicated the CASE group scored significantly lower on the FADI-S (26.7 + 4.1 points) than the CONTROL group (31.0 + 2.7 points) [p = 0.006]. The CASE group had significantly worse (higher) ASLST scores (1.58 + 0.35 degrees) compared to CONTROLS (1.05 + 0.35 degrees) [p = 0.045]. Binary logistic regression analyses indicated that for every 1-point decrease in FADI-S score, the odds of being diagnosed with CAI increased by a factor of 1.5 (p = 0.042). Conversely, for every 1-point increase in Overall Stability Index scores from the ASLST, the odds of being diagnosed with CAI increased by a factor of 0.03 (p = 0.045). CONCLUSIONS: The ASLST scores and FADI-S were significantly worse in the injured ankle of the CASE group compared to their contralateral normal ankle, and the matched ankles from the CONTROL group. A lower FADI-S and a higher ASLST score can be utilized to classify individuals as being more at risk for developing CAI.