Prevalence of knee osteoarthritis in the United States: arthritis data from the Third National Health and Nutrition Examination Survey 1991-94.

To estimate the US national prevalence of tibiofemoral radiographic knee osteoarthritis (RKOA) with and without symptoms, and its influence on functional tasks.

Radiographic and interview data from the National Health and Nutrition Examination Survey (NHANES III), a nationally representative cross-sectional health examination survey, were used to estimate lifetime RKOA prevalence in adults age 60 years and older. Demographic trends, self-reported activity limitations, physical performance test results, and patterns of recent analgesic use were analyzed.