title: Cross cultural adaptation and validation of a Spanish version of the Lower Limb Functional Index.
abstract: BACKGROUND
  The Lower Limb Functional Index (LLFI) is a relatively recently published regional outcome measure. The development article showed the LLFI had robust and valid clinimetric properties with sound psychometric and practical characteristics when compared to the Lower Limb Extremity Scale (LEFS) criterion standard.
  
  
  OBJECTIVE
  The purpose of this study was cross cultural adaptation and validation of the LLFI Spanish-version (LLFI-Sp) in a Spanish population.
  
  
  METHODS
  A two stage observational study was conducted. The LLFI was initially cross-culturally adapted to Spanish through double forward and single backward translation; then subsequently validated for the psychometric characteristics of validity, internal consistency, reliability, error score and factor structure. Participants (n = 136) with various lower limb conditions of >12 weeks duration completed the LLFI-Sp, Western Ontario and McMaster University Osteoarthritis Index (WOMAC) and the Euroqol Health Questionnaire 5 Dimensions (EQ-5D-3 L). The full sample was employed to determine internal consistency, concurrent criterion validity, construct validity and factor structure; a subgroup (n = 45) determined reliability at seven days concurrently completing a global rating of change scale.
  
  
  RESULTS
  The LLFI-Sp demonstrated high but not excessive internal consistency (α = 0.91) and high reliability (ICC = 0.96). The factor structure was one-dimensional which supported the construct validity. Criterion validity with the WOMAC was strong (r = 0.77) and with the EQ-5D-3 L fair and inversely correlated (r = -0.62). The study limitations included the lack of longitudinal data and the determination of responsiveness.
  
  
  CONCLUSIONS
  The LLFI-Sp supports the findings of the original English version as being a valid lower limb regional outcome measure. It demonstrated similar psychometric properties for internal consistency, validity, reliability, error score and factor structure.
authors.affiliation: Departamento de Psiquiatría y Fisioterapia, Facultad de Ciencias de la Salud, Universidad de Malaga, Andalucia Tech, Instituto de Biomedicina de Malaga (IBIMA), Grupo de Clinimetria (AE-14), Málaga, Spain. acuesta.var@gmail.com.
authors.forename: Antonio I
authors.initials: AI
authors.lastname: Cuesta-Vargas
authors.forename: Charles P
authors.initials: CP
authors.lastname: Gabel
authors.forename: Paul
authors.initials: P
authors.lastname: Bennett
mesh_terms: D000203:Activities of Daily Living / Q000523:psychology; D003431:Cross-Cultural Comparison; D005163:Factor Analysis, Statistical; D005260:Female; D006304:Health Status; D006801:Humans; D007866:Leg / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D011594:Psychometrics; D015203:Reproducibility of Results; D013030:Spain; D011795:Surveys and Questionnaires