The Greek version of TENDINS-A: translation, cross-cultural adaptation, a validity and reliability study in patients with Achilles tendinopathy

Background Achilles tendinopathy is a prevalent musculoskeletal condition characterised by pain, functional impairment, and reduced quality of life. Patient-reported outcome measures (PROMS) are critical for assessement. Although VISA-A is widely used, concerns have been raised regarding its content and structural validity. The TENDINS-A questionnaire was recently developed to address these limitations and provide a more comprehensive evaluation of Achilles Tendinopathy severity.Aim To translate, culturally adapt and validate the Greek version of TENDINS-A according to international COSMIN guidelines.Methods The process included forward–backward translation, expert panel review, and pilot testing in 15 patients and 15 physiotherapists. Seventy-two Greek-speaking participants with clinically diagnosed Achilles Tendinopathy completed TENDINS-A and VISA-A. Content validity was assessed through patient and expert ratings. Structural validity was examined with confirmatory factor analysis (CFA). Hypothesis testing (construct validity) was evaluated using hypotheses regarding the expected correlations between TENDINS-A and VISA-A, while reliability was assessed with Cronbach’s alpha, intraclass correlation coefficients (ICC), and test–retest analysis. Ceiling and floor effects were also explored.Results CFA confirmed the three-factor structure (CFI = 0.961, TLI = 0.945). Hypothesis testing was supported by a significant correlation with VISA-A (r = −0.299, p = 0.014). Internal consistency was acceptable (Cronbach’s α = 0.753), and test–retest reliability was excellent (ICC = 0.88–0.98). No ceiling or floor effects were detected.Conclusion The Greek version of TENDINS-A is a valid, reliable, and culturally appropriate patient-reported outcome measure for Achilles Tendinopathy. Its use can enhance standardised evaluation in both clinical practice and research.