Structural Validity and Measurement Properties of the Tampa Scale for Kinesiophobia in Knee Osteoarthritis: Comparison of Candidate Factor Structures

PURPOSE: Kinesiophobia is clinically relevant in knee osteoarthritis (KOA), but the appropriate Tampa Scale for Kinesiophobia (TSK) structure remains uncertain. We compared candidate TSK factor structures and examined the selected measurement properties of the solution with the most favourable relative fit in this sample. METHODS: Among 119 participants with KOA, ordinal confirmatory factor analysis tested three a priori structures: one-factor 17-item, one-factor 11-item, and two-factor 11-item. After three items in the two-factor 11-item structure had loadings below 0.20, a secondary exploratory 8-item solution was examined. For this exploratory solution, convergent validity, test-retest reliability, measurement error, composite reliability, and floor and ceiling effects were assessed. RESULTS: All a priori structures had borderline fit and weak loadings. Among the models examined, the exploratory two-factor 8-item solution had the highest CFI and TLI (0.948 and 0.924), although its RMSEA was the highest (0.078). Reliability was substantial for Somatic focus (ICC = 0.85) and Activity avoidance (ICC = 0.78), with low measurement error. Composite reliability was adequate only for Activity avoidance. CONCLUSION: The exploratory 8-item solution provided preliminary evidence, particularly for Activity avoidance, but requires independent validation.