More than half of all persons with symptomatic knee osteoarthritis (OA) are < 65 years, a recent study found. As many of these younger persons are predicted to live for 3 decades or more, there is substantially more time for greater disability to occur, and policymakers should anticipate health care utilization for knee OA to increase. Researchers calculated the prevalence of clinically diagnosed symptomatic knee OA from the National Health Interview Survey 2007–2008 and derived the proportion with advanced disease. They found:

• It was estimated that approximately 14 million persons had symptomatic knee OA, with advanced OA comprising more than half of those cases.
• This includes more than 3 million persons of racial/ethnic minorities (African American, Hispanic, and other).
• Adults <45 years of age represented nearly 2 million cases of symptomatic knee OA and individuals between 45 and 65 years of age comprised 6 million more cases.