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. Purpose: To assess the concurrent validity of the BPII to the Norwich Patellar Instability (NPI) score and the Kujala score. Study Design: 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