Superior responsiveness of the pain and function sections of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) as compared to the Lequesne-Algofunctional Index in patients with osteoarthritis of the lower extremities

OBJECTIVE: To compare the responsiveness of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and a questionnaire format of the Lequesne-Algofunctional Index in patients with OA of the lower extremities. METHODS: Longitudinal analysis of the instruments' responsiveness standardized response mean (SRM), effect size (ES)] in ambulatory patients undergoing hip or knee arthroplasty. RESULTS: At six months 36, and at one year 40 out of 43 patients undergoing hip (N=30) or knee arthroplasty (N=13) could be examined. Both responsiveness statistics revealed the same order of responsiveness. For both indices and for both locations, the pain sections were more responsive than the function sections. However, the WOMAC scales and the WOMAC global index (hip at 12 months: SRM=2.4; knee at 12 months: SRM=2.0 ) were more responsive than the comparable Lequesne sections and Lequesne index (hip at 12 months: SRM=2.1; knee at 12 months: SRM=1.5). CONCLUSIONS: Although our results are based on a German version using a self-report format, the WOMAC scales appear to be more responsive than the Lequesne index in patients with OA of the lower extremities.