The Cumberland Ankle Instability Tool: A Report of Validity and Reliability Testing
Presented in part to the Second International Ankle Symposium, October 15–16, 2004, Newark, DE (abstract appears in Br J Sports Med 2005;39:390) and the First World Conference of Sports Injury Prevention, June 23–25, 2005, Oslo, Norway (abstract appears in J Orthop Sports Phys Ther 2005;35:A20).
Abstract
Hiller CE, Refshauge KM, Bundy AC, Herbert RD, Kilbreath SL. The Cumberland Ankle Instability Tool: a report of validity and reliability testing.
Objective
To test the Cumberland Ankle Instability Tool (CAIT), a 9-item 30-point scale, for measuring severity of functional ankle instability.
Design
Cross-sectional study.
Setting
General community.
Participants
Volunteer sample of 236 subjects.
Interventions
Not applicable.
Main Outcome Measures
Concurrent validity by comparison with the Lower Extremity Functional Scale (LEFS) and a visual analog scale (VAS) of global perception of ankle instability by using the Spearman ρ. Construct validity and internal reliability with Rasch analysis using goodness-of-fit statistics for items and subjects, separation of subjects, correlation of items to the total scale, and a Cronbach α equivalent. Discrimination score for functional ankle instability by maximizing the Youden index and tested for sensitivity and specificity. Test-retest reliability by intraclass correlation coefficient, model 2,1 (ICC2,1).
Results
There were significant correlations between the CAIT and LEFS (ρ=.50, P<.01) and VAS (ρ=.76, P<.01). Construct validity and internal reliability were acceptable (α=.83; point measure correlation for all items, >0.5; item reliability index, .99). The threshold CAIT score was 27.5 (Youden index, 68.1); sensitivity was 82.9% and specificity was 74.7%. Test-retest reliability was excellent (ICC2,1=.96).
Conclusions
CAIT is a simple, valid, and reliable tool to measure severity of functional ankle instability.
aSchool of Physiotherapy, University of Sydney, Lidcombe, Australia
bSchool of Occupational and Leisure Sciences, University of Sydney, Lidcombe, Australia.
Reprint requests to Kathryn M. Refshauge, PhD, School of Physiotherapy, Faculty of Health Sciences, University of Sydney, PO Box 170, Lidcombe, Sydney, NSW 1825, Australia
Supported by the National Health and Medical Research Council of Australia.
No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the author(s) or upon any organization with which the author(s) is/are associated.
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