Translation, cross-cultural adaptation and psychometric properties of Urdu version of upper limb functional index; a validity and reliability study

BACKGROUND: The upper limb functional index is broadly used outcome measure for musculoskeletal disorders of the upper limb. The main objective of the study was to translate and validate the upper limb functional index (ULFI) outcome measure in the Urdu language. METHODS: Upper limb functional index was translated into Urdu language using Beaton et al. guidelines through forward and backward translation along with the expert committee reviews. Two fifty (n = 250) Urdu-speaking patients with sub-acute or chronic conditions of upper limb musculoskeletal disorders were included in the study. The mean age was 32.33 ± 4.67 years. The data were collected from the physical therapy department of The University of Lahore Teaching hospital. All participants completed the upper limb functional index-Urdu (ULFI-U), Numeric pain rating scale (NPRS), Quick Disability of arm, shoulder, and hand (QuickDash), and (health survey) SF-12 at baseline while only ULFI-U at day three. Reliability was assessed through internal consistency by Cronbach’s alpha and test-retest reliability by intra-class correlation (ICC). Content validity was measured by Lynn and Lawshee method. Spearman’s correlation has been used to measure criterion validity. The construct validity was measured through hypothesis testing. The structural validity has been explained through factor analysis by exploratory factor analysis (EFA) using Maximum likelihood extraction (MLE) with Promax rotation. RESULTS: The English version of ULFI was translated into the Urdu language with minor alterations. The Urdu version ULFI has demonstrated high levels of reliability with intra-class correlation (ICC(2,1=) 0.91) and Cronbach’s alpha (α = 0.94). The content validity index found as 0.808, the criterion validity for ULFI-U correlating with quick Dash was found excellent (r = 0.845) and ULFI-U established strong correlation with 6 domains of SF-12(r = 0.697 to 0.767) and weak correlation with its 2 domains and NPRS(r = 0.520). A two-factor structure was obtained using EFA. CONCLUSIONS: The ULFI-U is a valid and reliable patient-reported outcome (PRO) that can be used to assess upper limb musculoskeletal disorders in Urdu-speaking patients. TRIAL REGISTRATION: This study was registered in the U. S National Library on clinicaltrial.gov under registration no. NCT05088096. (Date: 21/10/2021).