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The lower extremity functional scale (LEFS): scale development, measurement properties, and clinical application
Binkley, J.M., Stratford, P.W., Lott, S.A., and Riddle, D.L. (1999). Phys. Ther. 79(4): 371–83.
The LEFS met test-retest reliability and internal consistency measures.
LEFS scores correlated with scores from the SF-36, indicating its construct validity.
Sensitive to change over time
Prognoses by physical therapists correlated with changes to patients’ LEFS scores over time.
At the time of this study, the Lower Extremity Functional Scale (LEFS) was a newly-developed condition-specific measure distinguished by its ease of application and scoring and its potential to apply to a broad range of lower-extremity orthopaedic conditions. To determine its usefulness as a clinical and research tool, the LEFS was evaluated based on its reliability, construct validity, and sensitivity to change.
To determine its internal reliability, the LEFS was administered and readministered to patients at set intervals. Construct validity was determined by administering the SF-36, a generic measure that has served as a comparison for condition-specific measures in past studies, at certain intervals, and then checking for correlations between the two measures. To evaluate the measures’ sensitivity to change, physical therapists provided prognoses for each of the patients, which were then correlated with changes to the patients’ LEFS and SF-36 scores during a set interval.
Results indicated that the LEFS is a reliable and valid measure for a broad range of lower-extremity conditions, and is also sensitive to change to a degree that makes it an appropriate measure to implement at the individual patient level. In fact, results showed that the LEFS is better at detecting changes in lower-extremity function than the SF-36.