Psychometric evidence of self-reported questionnaires for patellofemoral pain syndrome: a systematic review

Purpose: To conduct a systematic review of psychometric properties of self-reported questionnaires used to assess the level of symptoms and disability in individuals with patellofemoral pain syndrome (PFPS). Methods: A structured search was conducted in four databases (Medline, Embase, CINAHL, SportDiscus). A total of 24 studies about five different self-reported questionnaires were analyzed. A pair of independent raters extracted data on validity, reliability and responsiveness to change, and performed critical appraisal (0-100%). Results: Activities of Daily Living Scale (ADLS), Anterior Knee Pain Scale (AKPS), International Knee Documentation Committee (IKDC) and Lysholm Scale (LS) present excellent test-retest reliability (weighted average intraclass correlation coefficients [ICC] >0.80), whereas Functional Index Questionnaire (FIQ) is moderately reliable (ICC = 0.61). Minimal detectable change is 8.3% for ADLS, 9.0% for AKPS, 19% for FIQ, 8.5% for IKDC and 30% for LS. ADLS, AKPS, IKDC and LS are highly responsive (effect size/standardized response mean >0.95) in individuals with PFPS, while FIQ is lowly responsive (effect size = 0.49). Conclusion: Based on available evidence, ADLS presents the best psychometric properties and should be preferred when evaluating patients with PFPS. AKPS and IKDC are also adequate, while FIQ and LS are not recommended for individuals with PFPS.