The Lower Extremity Functional Scale Has Good Clinimetric Properties in People With Ankle Fracture

Abstract

There is limited information on the clinimetric properties of questionnaires of activity limitation in people after ankle fracture. The purpose of this study was to investigate the clinimetric properties of the Lower Extremity Functional Scale, an activity limitation questionnaire, in people with ankle fracture. This was a measurement study using data collected from 2 previous randomized controlled trials and 1 inception cohort study. Participants with ankle fracture (N=306) were recruited within 7 days of cast removal. Data were collected at baseline and at short- and medium-term follow-ups. Internal consistency and construct validity were assessed using Rasch analysis. Concurrent validity, responsiveness, and floor and ceiling effects were evaluated. The Lower Extremity Functional Scale demonstrated high internal consistency (alpha > .90). The variance in activity limitation explained by the items was high (98.3%). Each item had a positive correlation with the overall scale, and most items supported the unidimensionality of the scale. These findings suggest that the scale has high internal consistency and construct validity. The scale also demonstrated high concurrent validity and responsiveness in the short term and no floor or ceiling effects. However, the scale would benefit from more-challenging items, as evident at the medium-term follow-up. This was a secondary analysis of existing data sets. The Lower Extremity Functional Scale is a useful tool to monitor activity limitation in people with ankle fracture up to the short-term follow-up. More- difficult items may need to be added to improve the responsiveness of the scale for longer-term follow-up.