(HealthDay News) – The modified lower extremity functional scale (LEFS) is a valid and reliable instrument for patients with low back pain (LBP) with or without radiating leg pain, according to a study published in the Nov. 1 issue of Spine.

Huey-Wen Liang, MD, PhD, from the National Taiwan University Hospital, and colleagues recruited subjects (aged ≥18 years) with LBP from physical medicine and rehabilitation outpatient clinics to test the psychometric properties of the modified LEFS, in which the “lower limb problem” was substituted with “lower back/lower limb problem” in the introductory sentence of the questionnaire. Psychometric properties, including floor and ceiling effects, internal consistency, test-retest reliability, dimensionality, and construct validity were analyzed for 242 patients.

The researchers found that there were no floor or ceiling effects in the modified LEFS, which also had high internal consistency and good test-retest reliability. On principal component analysis, one major factor was identified that explained 49.6% of the total variance. There was high correlation between the modified LEFS and Roland-Morris Disability Questionnaire. Good discrimination was achieved between the subgroups of LBP with unilateral leg pain and those with bilateral leg pain using the modified LEFS.

“The modified LEFS had satisfactory psychometric properties in patients with LBP and could serve as a supplementary outcome measure to assess their activity limitations,” the authors conclude.

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