Ten-Item Lower Extremity Functional Scale (LEFS-10): Instrument Reduction Based on Brazilian Patients With Lower Limb Dysfunction.

Objective: To propose a short version of the lower extremity functional scale (LEFS), to compare our short version with the different structures proposed for the LEFS by the specialized literature, and to verify the criterion validity of the best structure of the LEFS identified in our study.

Design: Cross-sectional observational study.

Setting: Physiotherapy clinics.

Participants: We included 140 patients with lower limb dysfunction (N=140).

Interventions: None.

Main Outcome Measures: We used confirmatory factor analysis (CFA), χ/degree of freedom (DF), comparative fit index (CFI), Tucker-Lewis index (TLI), root mean square error of approximation (RMSEA), standardized root mean squared residual (SRMR), Akaike information criterion (AIC), and Bayesian information criterion (BIC). The method of reducing the number of items of the LEFS considered the modification indices and factor loadings.

Results: The body site most affected by pain was the knee (71.4%), and the most common diagnoses were knee osteoarthritis (55%) and anterior knee pain (11.4%). LEFS reduction generated a 1-dimensional structure of the LEFS with 10 items (LEFS-10). When compared with other structures, the LEFS-10 presented the best fit indices (χ/DF=1.88, CFI=0.975, TLI=0.968, RMSEA=0.079, and SRMR=0.058) and the lowest values of AIC (3287.063) and BIC (3345.896). LEFS-10 presents a high correlation (Spearman's correlation coefficient [ρ]=0.911, P<.001) with the 20-item LEFS.

Conclusion: LEFS-10 is the proposal for a short version of the instrument with the most adequate internal structure, in addition to being satisfactorily correlated with the longer version of the instrument.