Cross-Cultural Adaptation, Reliability, and Validity of the Greek Version of the Upper Extremity Functional Index

Introduction The Upper Extremity Functional Index (UEFI) is a region-specific questionnaire for patients with upper extremity disorders including patients with rotator cuff-related pain (RCRP). We aimed to translate and cross-culturally adapt the UEFI into Greek (UEFI-Gr) and evaluate its reliability and validity in a Greek-speaking population with RCRP. Methods Published guidelines for translation and cross-cultural adaptation of patient-rated outcome measures were followed. One hundred two patients were asked to complete the Greek versions of the UEFI; Disability of the Arm, Shoulder, and Hand (DASH) questionnaire; and RAND 36-Item Health Survey. Internal consistency, test-retest reliability, measurement error, content validity, concurrent validity, and ceiling and floor effects were evaluated. Results Minor linguistic discrepancies were identified and adopted in the Greek language. The UEFI-Gr presented high internal consistency (Cronbach's alpha: 0.93), excellent test-retest reliability (intraclass correlation coefficient: 0.91; 95% confidence interval {CI}: 0.79-0.95), and acceptable measurement error (standard error of measurement: 4.9 points; minimal detectable change {MDC}: 13.8 points). No ceiling or floor effects were detected. Strong correlations were found with the Greek versions of the Disability of the Arm, Shoulder, and Hand questionnaire (r=0.629; p<0.001) and weak to moderate correlations with most subdomains of RAND 36-Item Health Survey (r=0.30-0.59; p<0.05). Conclusions The UEFI-Gr is a comprehensive, reliable, and valid self-reported instrument to evaluate symptoms in patients with RCRP. Further research on the responsiveness of the questionnaire is necessary.