Bush's Knee Pain

President Bush has always been an avid runner, but in the past few months, knee pain put a halt to his normal jogging routine.

Doctors will perform an MRI test to have a closer look at the problem that plagues a lot of active "baby boomers."

The Early Show's Dr. Mallika Marshall explains what his doctors will look for, common problems in aging knees and ways to keep the knees healthy as one grows older.

Bush, 57, will have an MRI (magnetic resonance imaging) test on Thursday, Dec. 18. The body-scanning device enables doctors to see internal organs in 3D.

The MRI is being performed on the advice of the President's regular White House physician. Last summer, Bush suffered a minor muscle tear in his right calf and that injury, along with aching knees, forced him to abandon his running routine. The calf strain healed by August when he had his annual physical, but the president said in September that he suspected he had a meniscus tear.

The meniscus is the cartilage that lines the inside surfaces of the knee. It's a rubbery tissue that acts like a shock absorber between the upper and lower leg bones. There are two menisci, which help stabilize the knee joint. They're often injured or torn when we twist or pivot while playing sports, for example. And in older people, worn menisci are easier to tear.

Symptoms can include pain, swelling, or stiffness when you're climbing stairs, for example. These symptoms usually go away within two or three weeks, which indicates that the tear is healing on its own. But in severe tears, pieces of the meniscus can migrate into the joint space, and there can even be bleeding in the joint.

Once the doctors assess the extent of the damage, they may recommend a temporary knee brace or physical therapy. In more serious cases, some people need surgery to repair the meniscus by stitching it back together; other times it's necessary to remove the torn section, or even to remove the meniscus.

In the past decade, orthopedists report a record number of hospital visits by "baby boomers" due to sports injuries. Some orthopedic surgeons refer to it as "boomeritis."

Marshall says the "baby boomers" are really the first generation that expects to be fit and active well into old age. Although he can't jog right now, the president is reported to be working out on an elliptical trainer and he's doing water aerobics.

Even for sedentary people, the knees change with age. Flexibility decreases because of changes in the tendons and ligaments. Over time, the cushioning cartilage starts to break down from a lifetime of use, and the joints can become inflamed and arthritic.

More baby boomers are asking for knee replacement surgery. But before they go that route, doctors recommended lifestyle changes.

Marshall recommends the following to protect aging knees: