Reliability, Validity, and Responsiveness of the Lower Extremity Functional Scale for Inpatients of an Orthopaedic Rehabilitation Ward

Abstract

Single-group, repeated-measures study. To estimate the test-retest reliability, construct validity, and responsiveness of the Lower Extremity Functional Scale (LEFS) on inpatients attending an orthopaedic rehabilitation ward. The LEFS has acceptable validity on outpatients in assessing functional mobility, but it has not been tested for use on an inpatient orthopaedic ward. Inpatients in an orthopaedic ward (n = 142) completed the 20-item, self-report LEFS on admission, 7 to 10 days after admission, and on discharge. To test reliability, 24 patients had the LEFS repeated 1 day after the admission test, and the intraclass correlation (ICC) and the standard error of measurement (SEM) were calculated. Change scores of the LEFS were evaluated against patients' and therapists' rating of improvement, and change scores of comparison measures that included pain, functional performance, and the composite index created from scores of these comparison measures. The standardized response mean (SRM) of the LEFS was also computed. The ICC of the LEFS was 0.88, and the SEM was 4 LEFS points (LEFS score range, 0-80). The change in LEFS correlated with changes of comparison measures in the same direction of improvement. Patients rated as improved by both themselves and their therapists had significantly larger change in LEFS scores than subjects rated as no change. The SRM of the LEFS from admission to discharge was 1.76 on patients rated as improved. The LEFS is reliable and valid to assess group and individual change, and has large responsiveness. The LEFS and the comparison measures likely assess different constructs.