Cross-cultural translation and validation of the Greek version of the Knee Injury and Osteoarthritis Outcome Score (KOOS) in patients with total knee replacement.

Purpose: Aim of this study is to assess the psychometric properties of the developed Greek version of the Knee Injury and Osteoarthritis Outcome Score (KOOS) in total knee replacement (TKR) patients.

Methods: Psychometric properties of the Greek version of KOOS were evaluated according to the Consensus-based Standards Measurements Instruments (COSMIN) checklist. Patients' pre-operative clinical status and post-operative outcomes at two occasions (at discharge and 10-12 days post-operatively) were evaluated using the KOOS, KOS-ADL and SF-12 Health Survey.

Results: A comprehensive Greek KOOS was piloted and well accepted by patients and therefore administered to 60 consecutive TKR patients (mean age 72.2 ± 7.2 years, 39 women). Excellent Internal consistency, good test-retest reliability of KOOS and KOOS 5 subdomains, respectively [ICC(2-1) 0.76, 95% CI = 0.235-0.902 and 0.89, 95% CI = 0.843-0.927] was yielded. A priori hypotheses for construct validity were confirmed with KOOS score and subdomains for pain, symptoms and Everyday Living function (ADL) correlating moderately with KOS-ADL. Responsiveness for KOOS subdomains of Pain and Symptoms yielded moderate effect size (ES = 0.4).

Conclusion: The Greek KOOS was found to be a practical and comprehensible self-reported measure for TKR patients with acceptable psychometric properties. It is therefore, recommendable for usage in future clinical trials and clinical practice. Implications for Rehabilitation The Greek version of KOOS is an essential assessment scale to evaluate not only acute injuries but also chronic knee associated conditions in a holistic perspective. The Greek KOOS has been found to be a practical and comprehensible self-reported measure for TKR patients with acceptable psychometric properties, recommendable for usage in future clinical trials and clinical practice. KOOS Greek version (downloadable at the official site http://www.koos.nu/koosgreek.pdf ) was used in the validity study.