title: Validation of the instability shoulder index score in a multicenter reliability study in 114 consecutive cases.
abstract: BACKGROUND
  Anterior shoulder stabilization surgery with the arthroscopic Bankart procedure can have a high recurrence rate in certain patients. Identifying these patients to modify outcomes has become a focal point of research.
  
  
  OBJECTIVE
  The Instability Shoulder Index Score (ISIS) was developed to predict the success of arthroscopic Bankart repair. Scores range from 0 to 10, with higher scores predicting a higher risk of recurrence after stabilization. The interobserver reliability of the score is not known.
  
  
  METHODS
  Cohort study (diagnosis); Level of evidence, 2.
  
  
  METHODS
  This is a prospective multicenter (North America and Europe) study of patients suffering from shoulder instability and waiting for stabilization surgery. Five pairs of independent evaluators were asked to score patient instability severity with the ISIS. Patients also completed functional scores (Western Ontario Shoulder Instability Index [WOSI], Disabilities of the Arm, Shoulder and Hand-short version [QuickDASH], and Walch-Duplay test). Data on age, sex, number of dislocations, and type of surgery were collected. The test-retest method and intraclass correlation coefficient (ICC: >0.75 = good, >0.85 = very good, and >0.9 = excellent) were used for analysis.
  
  
  RESULTS
  A total of 114 patients with anterior shoulder instability were included, of whom 89 (78%) were men. The mean age was 28 years. The ISIS was very reliable, with an ICC of 0.933. The mean number of dislocations per patient was higher in patients who had an ISIS of ≥6 (25 vs 14; P = .05). Patients who underwent more complex arthroscopic procedures such as Hill-Sachs remplissage or open Latarjet had higher preoperative ISIS outcomes, with a mean score of 4.8 versus 3.4, respectively (P = .002). There was no correlation between the ISIS and the quality-of-life questionnaires, with Pearson correlations all >0.05 (WOSI = 0.39; QuickDASH = 0.97; Walch-Duplay = 0.08).
  
  
  CONCLUSIONS
  Our results show that the ISIS is reliable when used in a multicenter study with anterior traumatic instability populations. There was no correlation between the ISIS and the quality-of-life questionnaires, but surgical decisions reflected its increased use.
authors.affiliation: Université de Montréal, Hôpital du Sacré-Cœur de Montréal, 5400 W Gouin Blvd, Suite C2095, Montréal, Québec, Canada H4J 1C5.
authors.forename: Dominique M
authors.initials: DM
authors.lastname: Rouleau
authors.forename: Jonah
authors.initials: J
authors.lastname: Hébert-Davies
authors.forename: Ali
authors.initials: A
authors.lastname: Djahangiri
authors.forename: Véronique
authors.initials: V
authors.lastname: Godbout
authors.forename: Stéphane
authors.initials: S
authors.lastname: Pelet
authors.forename: Frédéric
authors.initials: F
authors.lastname: Balg
mesh_terms: D000328:Adult; D001182:Arthroscopy; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000175:diagnosis* / Q000601:surgery; D008297:Male; D012307:Risk Factors; D012720:Severity of Illness Index; D012783:Shoulder Dislocation / Q000175:diagnosis* / Q000601:surgery; D012785:Shoulder Joint