title: Concurrent Validation of the Banff Patella Instability Instrument to the Norwich Patellar Instability Score and the Kujala Score in Patients With Patellofemoral Instability.
abstract: BACKGROUND
  The Banff Patella Instability Instrument (BPII) is a disease-specific, patient-reported, quality-of-life outcome measure designed to assess patients with patellofemoral instability. The iterative assessment of the validity, reliability, and responsiveness of a health-related patient-reported outcome measure is vital to the development of a high-quality evaluation tool.
  
  
  OBJECTIVE
  To assess the concurrent validity of the BPII to the Norwich Patellar Instability (NPI) score and the Kujala score.
  
  
  METHODS
  Cohort study; Level of evidence, 2.
  
  
  METHODS
  A total of 74 patients with a confirmed diagnosis of recurrent patellofemoral instability completed the BPII, NPI, and Kujala scores at the initial orthopaedic consultation. A Pearson r correlation coefficient was computed to determine the relationship between each of these patient-reported outcomes.
  
  
  RESULTS
  There were statistically significant correlations between the BPII and the NPI score (r = -0.53; P < .001) as well as the BPII and the Kujala score (r = 0.50; P < .001).
  
  
  CONCLUSIONS
  This study demonstrated a moderately strong correlation of the BPII to other outcome measures used to evaluate patients with patellofemoral instability. This study adds further validity to the BPII in accordance with the COSMIN (COnsensus-based Standards for the selection of health Measurement INstruments) guidelines.
authors.affiliation: Banff Sport Medicine, Banff, Alberta, Canada.; Department of Surgery, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Laurie A
authors.initials: LA
authors.lastname: Hiemstra
authors.affiliation: Banff Sport Medicine, Banff, Alberta, Canada.; Department of Physical Therapy, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Sarah
authors.initials: S
authors.lastname: Kerslake
authors.affiliation: Department of Health and Physical Education, Mount Royal University, Calgary, Alberta, Canada.
authors.forename: Mark
authors.initials: M
authors.lastname: Lafave
authors.affiliation: Department of Surgery, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Nicholas G
authors.initials: NG
authors.lastname: Mohtadi
keywords: Banff Patella Instability Instrument (BPII); COSMIN; Kujala score; Norwich Patellar Instability score (NPI); outcome measure; patellofemoral instability; quality of life