of people in the United States living with an artificial hip or knee is likely to increase in the coming decades, creating significant challenges for provision of specialized health care services and for the management of revision surgeries and long-term complications, according to a study presented at the American Academy of Orthopaedic Surgeons Annual Meeting.

To estimate 2010 prevalence rates according to age, sex and time since surgery, researchers reviewed total hip arthroplasty (THA) and total knee arthroplasty (TKA) incident rates, mortality rates and relative mortality rates during a 40-year period.

Researchers estimated a 1.5% prevalence of THA and a 2.2% prevalence of TKA in 2010, with 4.5 million people living with an artificial hip and 6.7 million people living with an artificial knee. California, Florida and Texas had theThe Australian Open begins on Monday, and Thursday gave us the draw, which means we now know who's playing who. One of the first things that jumps off the bracket is that Roger Federer and Novak Djokovic could play each other in the finals. Both of them have six Australian Open titles, tied with Roy Emerson for the most ever, so they could be playing for the most ever if they get through their respective brackets.

To view the full draw and bracket for the Australian Open, click here.

One the women's side, Serena Williams is trying to win her 24th Grand Slam, which would tie her with Margaret Court for the most ever. Williams has made the last two women's singles finals, losing to Angelique Kerber at Wimbledon and