Item‐reduced Forgotten Joint Score provides adequate psychometric properties in ACLR patients

Abstract

Abstract Purpose The purpose of this study was to evaluate content validity, test–retest reliability, internal consistency, construct validity, responsiveness and floor/ceiling effects of Forgotten Joint Score (FJS) for assessing functions in activities of daily living (ADL) following anterior cruciate ligament reconstruction (ACLR) and perform an item reduction of FJS. Methods Swedish‐speaking ACLR patients in one surgical clinic were eligible. Content validity was evaluated through patient responses and patient and expert clinician relevance ratings, omitting items with low relevance. Principal component factor analysis, Cronbach's ⍺, paired t test, correlations between FJS and Knee Injury and Osteoarthritis Outcome Score (KOOS), Cohen's d effect sizes (ESs) and standardized response mean (SRM) were used to evaluate internal consistency, test–retest reliability, construct validity and responsiveness. Floor/ceiling effects were calculated. FJS was expected to reveal one dominant factor, a Cronbach's ⍺ between 0.70 and 0.95, correlations >0.50 to all KOOS subscores, highest for ADL, moderate ES and SRM, floor/ceiling effects 0.90. FJS showed significant correlations >0.65 to all KOOS subscales, moderate ES and SRM > 0.50. No floor/ceiling effects were found. Conclusion FJS‐9 demonstrated adequate validity for the evaluation of joint awareness in ACLR patients and can be a valuable tool to assess ADL and joint awareness. Level of Eidence Level III.

Keywords

• ACL
• ACL reconstruction
• Forgotten Joint Score
• patient‐reported outcome
• validation