Hip Disability and Osteoarthritis Outcome Score and Western Ontario and McMaster Universities Osteoarthritis Index Values in Asymptomatic and Arthritic Cohorts.

The primary aim of this study was to determine whether an electronic, multicenter data collection system could be used to establish normal population reference values for the Hip Disability and Osteoarthritis Outcome Score (HOOS) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). The secondary aim was to investigate differences in asymptomatic HOOS and WOMAC values reported in 2 geographically distinct English-speaking countries and compare these with a symptomatic arthritic patient cohort. A total of 552 participants were recruited. Asymptomatic Australian and Canadian cohorts were compared; combined asymptomatic cohorts were compared with an arthritic cohort. There was a statistically significant association between age and asymptomatic HOOS (P<.0001) and WOMAC (P<.0001) values; as age increased, values worsened. Females had worse HOOS and WOMAC values (P<.0001). When compared with age- and sex-matched asymptomatic participants, arthritic participants had worse scores (P<.0001). Asymptomatic Australians had a statistically significant 3.8% better (higher) HOOS (P<.0001) in all age groups (P<.0001). When compared with age- and sex-matched asymptomatic participants, younger arthritic participants reported worse activities of daily living and sports and recreation HOOS values. This observational study established an electronic HOOS and WOMAC patient-reported outcome measures database of asymptomatic individuals in 2 geographically distinct countries. An asymptomatic control group should be sourced from the same country of origin as the proposed study. Factors that should be considered when recording the HOOS and WOMAC include age, sex, geographic location, history of an inactive hip problem, contralateral hip disease, and active knee, ankle, or foot problems. [Orthopedics. 201x; xx(x):xx-xx.].