Cross-Cultural Adaptation and Validation of the German Version of the Upper Limb Functional Index.

Context: The Upper Limb Functional Index (ULFI) is a popular tool with valid psychometric properties to assess upper limb function in patients with musculoskeletal conditions. The aim of the study was to cross-culturally adapt and validate the German version of the ULFI.

Design: Cross-cultural validation.

Methods: A 2-stage cross-cultural adaptation of the ULFI was performed according to international guidelines through consecutive forward and backward translations. Psychometric properties of internal consistency, test-retest reliability, criterion, face and content validity, and factor structure were determined from the included German participants suffering from upper limb conditions (n = 100), who fulfilled the following inclusion criteria: (1) older than 18 years old, (2) German as native language, and (3) medical diagnosis of musculoskeletal upper limb condition. Participants completed the ULFI; Disabilities of the Arm, Shoulder, and Hand; EuroQol Health Questionnaire 5 Dimensions; and Short Form-12 questionnaires.

Results: The ULFI-G showed good internal consistency (α = .88); excellent test-retest reliability (intraclass correlation coefficient2:1 = .98); directly strong correlation with Disabilities of the Arm, Shoulder, and Hand (r = .84); fair correlation with Disabilities of the Arm, Shoulder, and Hand-sport (r = .54); inversely fair correlation with EuroQol Health Questionnaire 5 Dimensions (r = -.62); and Short Form 12's physical health domain (r = -.7). A single-factor structure was revealed.

Conclusions: The ULFI-G showed adequate psychometric properties and proved to be a valid tool for upper limb functional assessment in German population.