title: Discriminating between copers and people with chronic ankle instability.
abstract: BACKGROUND
  Differences in various outcome measures have been identified between people who have sprained their ankles but have no residual symptoms (copers) and people with chronic ankle instability (CAI). However, the diagnostic utility of the reported outcome measures has rarely been determined. Identifying outcome measures capable of predicting who is less likely to develop CAI could improve rehabilitation protocols and increase the efficiency of these measures.
  
  
  OBJECTIVE
  To determine the diagnostic utility and cutoff scores of perceptual, mechanical, and sensorimotor outcome measures between copers and people with CAI by using receiver operating characteristic curves.
  
  
  METHODS
  Case-control study.
  
  
  METHODS
  Sports medicine research laboratory.
  
  
  METHODS
  Twenty-four copers (12 men, 12 women; age = 20.8 ± 1.5 years, height = 173 ± 11 cm, mass = 78 ± 27 kg) and 24 people with CAI (12 men, 12 women; age = 21.7 ± 2.8 years, height = 175 ± 13 cm, mass = 71 ± 13 kg) participated.
  
  
  METHODS
  Self-reported disability questionnaires, radiographic images, and a single-legged hop stabilization test.
  
  
  METHODS
  Perceptual outcomes included scores on the Foot and Ankle Disability Index (FADI), FADI-Sport, and a self-report questionnaire of ankle function. Mechanically, talar position was quantified by measuring the distance from the anterior tibia to the anterior talus in the sagittal plane. Sensorimotor outcomes were the dynamic postural stability index and directional indices, which were calculated during a single-legged hop stabilization task.
  
  
  RESULTS
  Perceptual outcomes demonstrated diagnostic accuracy (range, 0.79-0.91), with 95% confidence intervals ranging from 0.65 to 1.00. Sensorimotor outcomes also were able to discriminate between copers and people with CAI but with less accuracy (range, 0.69-0.70), with 95% confidence intervals ranging from 0.37 to 0.86. The mechanical outcome demonstrated poor diagnostic accuracy (0.52).
  
  
  CONCLUSIONS
  The greatest diagnostic utility scores were achieved by the self-assessed disability questionnaires, which indicated that perceptual outcomes had the greatest ability to accurately predict people who became copers after their initial injuries. However, the diversity of outcome measures that discriminated between copers and people with CAI indicated that the causal mechanism of CAI is probably multifactorial.
authors.affiliation: Department of Kinesiology, University of North Carolina at Charlotte, 9201 University City Boulevard, Charlotte, NC 28223, USA. ewikstrom@uncc.edu
authors.forename: Erik A
authors.initials: EA
authors.lastname: Wikstrom
authors.forename: Mark D
authors.initials: MD
authors.lastname: Tillman
authors.forename: Terese L
authors.initials: TL
authors.lastname: Chmielewski
authors.forename: James H
authors.initials: JH
authors.lastname: Cauraugh
authors.forename: Keith E
authors.initials: KE
authors.lastname: Naugle
authors.forename: Paul A
authors.initials: PA
authors.lastname: Borsa
mesh_terms: D000223:Adaptation, Psychological; D000842:Ankle / Q000503:physiopathology; D016512:Ankle Injuries / Q000175:diagnosis* / Q000503:physiopathology; D000843:Ankle Joint / Q000503:physiopathology; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000175:diagnosis*; D008297:Male; D017063:Outcome Assessment, Health Care; D010465:Perception; D004856:Postural Balance; D057566:Self Report; D013180:Sprains and Strains / Q000175:diagnosis*; D011795:Surveys and Questionnaires; D055815:Young Adult