Cross-Cultural Adaptation and Validation of the Thai Version of the Knee Injury and Osteoarthritis Outcome Score for Patellofemoral Pain and Osteoarthritis (KOOS-PF)

Abstract

Background: The Knee injury and Osteoarthritis Outcome Score for patellofemoral pain and osteoarthritis (KOOS-PF) is a condition-specific patient-reported outcome measure that is used to evaluate patients with patellofemoral pain. Purpose: To translate the KOOS-PF into the Thai language, to make necessary adaptations to a Thai cultural context, and to assess the measurement properties of the Thai version of the KOOS-PF (TH-KOOS-PF) using the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) checklist. Study Design: Cohort study (diagnosis); Level of evidence, 3. Methods: This study was conducted between December 2021 and May 2023. Language translation of the KOOS-PF was performed according to guidelines for the cross-cultural adaptation of self-report measures. Eligible participants aged 18 to 50 years were asked to complete various patient-reported outcome measures including the TH-KOOS-PF at 3 time points: baseline, 2 weeks after baseline for test-retest reliability analysis, and 2 months after baseline for responsiveness assessment. Results: The KOOS-PF was successfully translated and culturally adapted to create the TH-KOOS-PF. A total of 86 participants (mean age, 37.0 ± 8.1 years; 59.3% female) with patellofemoral pain participated in the validation process. Construct validity of the TH-KOOS-PF was demonstrated by confirmation of all a priori hypotheses. The standardized Cronbach alpha coefficient was 0.88 (95% CI, 0.83-0.91), which indicated good internal consistency. Test-retest reliability was high, with an intraclass correlation coefficient of 0.87 (95% CI, 0.77-0.92). The TH-KOOS-PF demonstrated good responsiveness, as evidenced by all predefined hypotheses’ being confirmed, and there were no floor or ceiling effects. Using an anchor-based approach, the minimal clinically important difference was 11.6 points. Conclusion: The results of this study revealed the TH-KOOS-PF to be a valid, reliable, and responsive tool for assessing Thai patients with patellofemoral pain. The TH-KOOS-PF will be useful in both clinical and research settings.