Chinese adaptation and validation of the Patellofemoral Pain Severity Scale

Objective: This study validated the Patellofemoral Pain Severity Scale translated into Chinese. Design and setting: The Chinese Patellofemoral Pain Severity Scale was translated from the original English version following standard forward and backward translation procedures recommended by the International Society for Pharmacoeconomics and Outcomes Research. The survey was then conducted in clinical settings by a questionnaire comprising the Chinese Patellofemoral Pain Severity Scale, Kujala Scale and Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index. Subjects: Eighty-four Chinese reading patients with patellofemoral pain were recruited from physical therapy clinics. Main measures: Internal consistency of the translated instrument was measured by Cronbach alpha. Convergent validity was examined by Spearman rank correlation coefficient (rho) tests by comparing its score with the validated Chinese version of the Kujala Scale and the WOMAC Osteoarthritis Index while the test–retest reliability was evaluated by administering the questionnaires twice. Results: Cronbach alpha values of individual questions and their overall value were above 0.85. Strong association was found between the Chinese Patellofemoral Pain Severity Scale and the Kujala Scale (rho = –0.72, p < 0.001). Moderate correlation was also found between Chinese Patellofemoral Pain Severity Scale with the WOMAC Osteoarthritis Index (rho = 0.63, p < 0.001). Excellent test–retest reliability (Intraclass correlation coefficient = 0.98) was demonstrated. Conclusions: The Chinese translated version of the Patellofemoral Pain Severity Scale is a reliable and valid instrument for patients with patellofemoral pain.