Psychometric properties of Patient-Specific Functional Scale in patients with upper extremity disorders. A systematic review

PURPOSE: To identify, critically appraise, and synthesise the measurement properties of Patient-Specific Functional Scale (PSFS) in patients with upper extremity musculoskeletal disorders. METHODS: Medline, Embase, PubMed, and Google Scholar databases from January 1999 to November 2020 were searched. Prospective measurement studies that included patients with upper extremity musculoskeletal disorders, that reported on the psychometric properties of PSFS were included. We used the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) 2018 guideline for systematic reviews to appraise the studies. RESULTS: Fourteen eligible studies were included. Three studies with adequate-very good quality and sufficient properties indicated excellent intra-class correlation coefficients (ICC) (≥0.75) in patients with shoulder pain (mean age 48 ± 11 years), multiple shoulder disorders (mean age 55 ± 16 years), and hand osteoarthritis (mean age 64 ± 9 years). The construct validity estimates of PSFS were moderate, when compared with Upper Extremity Functional Index (UEFI) (r = 0.50) and Numeric Pain Rating Scale (NPRS) (r = 0.51) in patients with combined upper extremity musculoskeletal disorders (shoulder/upper arm, wrist/hand and elbow/forearm). CONCLUSIONS: The patient-specific functional scale can be considered as a reliable, valid, and responsive tool in assessing functional change in patients with shoulder disorders/pain.Implications for rehabilitationThe Patient-Specific Functional Scale (PSFS) can be considered as: • a reliable outcome measure in assessing functional change in patients with shoulder pain and hand osteoarthritis; • a valid measure in assessing functional limitation in patients with upper extremity disorders; • a measure that is sensitive to change (displays longitudinal validity) in assessing functional change in patients with upper extremity disorders and in patients with shoulder pain; and • a responsive outcome measure in assessing functional change in patients with upper extremity disorders.