Why are cases of knee osteoarthritis on the rise?
A new study found osteoarthritis of the knee is more than twice as common as it was just a few generations ago. It's estimated the lifetime risk of developing this condition is 46 percent, but it is possible to protect your knees. Dr. Jordan Metzl, a sports medicine physician at New York's Hospital for Special Surgery, joins "CBS This Morning" to discuss possible reasons for the increase and what you can do to reduce the symptoms.