Validity and Reliability of the Indonesian Version of the Kujala Score for Patients With Patellofemoral Pain Syndrome

Background: The Kujala score is a useful diagnostic tool to evaluate patellofemoral pain syndrome (PFPS). However, no validated Indonesian version of the Kujala score has been available. Purpose: To develop and validate an Indonesian version of the Kujala score. Study Design: Cohort study (diagnosis); Level of evidence, 3. Methods: This was a cross-sectional study to develop an Indonesian version of the Kujala score by using a forward-backward translation protocol. The resulting questionnaire was given to 51 patients diagnosed with PFPS. The validity of the questionnaire was evaluated by correlating the final score with the Indonesian version of the 36-Item Short Form Health Survey (SF-36). Reliability was measured by evaluating the internal consistency (Cronbach alpha) and test-retest reliability (intraclass correlation coefficient [ICC]). Results: The Indonesian version of the Kujala score had a positive correlation with the physical components of the SF-36. The internal consistency was fairly high (alpha = .74), and the test-retest reliability was excellent (ICC, 0.996). Conclusion: The Indonesian version of the Kujala score was proven to be a valid and reliable tool to diagnose PFPS. Future epidemiological studies could implement this score to find the prevalence of PFPS in Indonesia. Further, ensuing studies could explore the application of this scoring system in posttreatment and postoperative settings.