Measurement properties of the Knee Injury and Osteoarthritis Outcome Score Patello-Femoral questionnaire in Saudi Arabians.

Background. No Arabic or its dialect questionnaire is available to evaluate the anterior knee pain in the Saudi Arabian religious population. This study aims to translate, adapt, and psychometrically validate the Knee Injury and Osteoarthritis Outcome Score (KOOS-PF) Patellofemoral scale in the Arabic language in Saudi Arabic dialect. Method. Translation has been done as per standard guidelines. The questionnaire was administered to 95 patients to determine the psychometric properties including on two different occasions, with a 48-hour gap in-between; to ensure that their answers were reliable; 84 patients (88.4% compliance rate) responded for test and retest reliability, ceiling-floor effects, validity and other psychometric criteria. Results. Cronbach's alpha (internal consistency) and test-retest reliability was good and excellent (infinity = 0.81; ICC > 0.95). None of the items showed >30% floor or ceiling effect and the minimal detectable change was within the acceptable range (<30%). The KOOS-PF subscale showed a moderate correlation (-0.568) with pain-visual analog scale for its construct validity. Conclusion. The Arabic dialect of KOOS-PFis reliable and valid to be used to evaluate isolated knee pain of patellofemoral origin in Muslim patients in Saudi Arabia.