Validation of a Japanese patient-derived outcome scale for assessingtotal knee arthroplasty: comparison with Western Ontario andMcMaster Universities osteoarthritis index (WOMAC)

Abstract

We have developed a Japanese self-administeredquestionnaire based on an English version of the WesternOntario and McMaster Universities osteoarthritis index(WOMAC) to measure subjective function and pain status ofpatients who undergo a total knee arthroplasty procedure.Using multiple international cohorts, the performance of thedeveloped Japanese scale was compared to the results of theWOMAC in the United Kingdom, United States, Canada, andAustralia. The developed scale showed a comparable levelof internal consistency and construct/criterion validity. Theresponsiveness of the scale was superior to the concurrentlymeasured MOS Short Form 36 Physical Function scale. Theseresults suggest that the developed scale is reliable, valid, andresponsive for assessing the effectiveness of total knee arthroplastyin the Japanese context despite the cultural life styledifferences from Western countries.