CAN THE WESTERN ONTARIO AND MCMASTER UNIVERSITIES (WOMAC) OSTEOARTHRITIS INDEX BE USED TO EVALUATE DIFFERENT HIP JOINTS IN THE SAME PATIENT

The Western Ontario and McMaster Universities (WOMAC) osteoarthritis i ndex was originally designed for disease-specific evaluation of patien ts with lower extremity osteoarthritis (1988), but has not bren valida ted for evaluation of more than one joint at the same time in the same patient. Thirty-three patients with bilateral total hip arthroplastie s answered a questionnaire containing both the WOMAC osteoarthritis in dex and the Harris hip score (HHS) (1969), a joint-specific health sta tus measure that was designed to include evaluation of bilateral hip a rthroplasty. Differences in scores between hips were highly correlated for HSS and WOMAC total score (P = .0001), HHS pain and WOMAC pain su bscores (P = .0001), and HHS function and WOMAC physical function subs cores (P = .0001). WOMAC stiffness and HHS range oi motion were not si gnificantly correlated (P = .1308). In 23 patients (70%), both scores graded the hips with the same comparative outcome. When comparative ou tcomes were different, the average difference was less than 3 points ( of 100 possible points). These results demonstrate that patients with bilateral hip arthroplasty can apply the WOMAC osteoarthritis index qu estions to individual hips at the same lime as effectively as the join t-specific HHS questions.