Description
Objectives: This study aims to translate and culturally adapt the subscale of the Knee Injury and Osteoarthritis Outcome Score for patellofemoral pain and osteoarthritis (KOOS-PF) into Turkish and to determine the measurement properties of the Turkish version.
Methods: The Turkish version of the KOOS-PF was tested for reliability and validity in a convenience sample of 55 patients with patellofemoral pain and/or osteoarthritis. Reliability analyses were conducted through a retest 7–14 days later with a subgroup of 35 patients. The KOOS-PF was compared with the Kujala's Anterior Pain Scale (AKPS) and the Short Form-36 health survey (SF-36) to assess construct validity. Additionally, responsiveness analyses were performed on 29 patients who were followed up with a home-based exercise program three months later.
Results: The demographic and clinical characteristics of the patients participating in the study are summarized in Table 1. The KOOS-PF revealed high test-retest reliability for patients who completed both the first and second assessments (n = 35). The Turkish version of KOOS-PF demonstrated high test-retest reliability (the intraclass correlation coefficient = 0.96) and internal consistency (Cronbach's α = 0.91) (Table 2). The KOOS-PF demonstrated a very good correlation (r = 0.768) with the AKPS. Also, the KOOS-PF had very good and weak correlations ( r = 0.635, r = 0.404) with the SF-36 physical component and mental component scores, respectively (Table 3). Exploratory factor analysis and confirmatory factor analysis were performed to create evidence of the scale's construct validity. According to the analysis, it constitutes 58.37% of the total variance of the KOOS-PF, which supports the fact that the PROM has a single-factor structure. A good correlation was observed between the KOOS-PF change and GROC scores (r = 0.510). There were no floor or ceiling effects, and none of the patients received the minimum or maximum score for the KOOS-PF. The SDC for the individual was measured at 14.5; for the group, it was recorded at 1.2. Also, the MIC was calculated at 16.5, and the MID was determined to be 10.2.
Conclusions: The KOOS-PF was successfully translated into Turkish for this study, and the results showed adequate measurement properties that were consistent with the original version, including high test-retest and internal consistency, very good construct validity, and good responsiveness. The Turkish version of KOOS-PF can be utilized for clinical and research use in patients with patellofemoral pain and osteoarthritis.
