Comparison of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the Lower Extremity Functional Scale (LEFS) Questionnaires in Patients Awaiting or Having Undergone Total Knee Arthroplasty

Purpose: The purpose of this study was to determine the relationship between two functionally oriented health status measures, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the Lower Extremity Functional Scale (LEFS), in patients awaiting or having undergone total knee arthroplasty (TKA). Methods: Patients who were on the waiting list for TKA (n = 150) or who had undergone TKA (n = 150) received a mailed questionnaire. Results: Responses were tabulated for 187 completed questionnaires. Although correlations of r = .87 to .89 were observed between scores on the WOMAC physical function and the LEFS questionnaires, the standard error of estimate associated with using one questionnaire to predict scores on the other was large (F6 to F8). The relative efficiency of the WOMAC and the LEFS was similar, as were their relationships with the patients' ability to walk and ascend or descend stairs. Respondents indicated no clear preference for either questionnaire. Conclusions: Although related, scores from the WOMAC and the LEFS were not directly interchangeable. Both the WOMAC and the LEFS have advantages. Clinicians' use of one or both of these health status measures in patients with TKA depends on their anticipated use of the information.