Knees and Hips: A troubleshooting guide to knee and hip pain

Prepared by the editors of Harvard Health Publications in consultation with, Scott David Martin M.D., assistant professor of orthopedic surgery, Harvard Medical School and attending orthopedic surgeon, Brigham and Women's Hospital, Boston, Mass.

Ten thousand steps a day. Tha's how far you must walk to meet government guidelines for physical activity to improve health. But if, like millions of people, you find walking painful or you fear your joints might buckle beneath you, each step might as well be a mile.

Your knees and hips are your largest joints, and they support your body's weight while allowing your legs to move freely. Even walking at a leisurely pace puts a force that is double your body weight on each leg. Running or descending stairs quadruples that force.

The pressure can take a heavy toll. According to government health surveys, hip and knee pain is on the rise in older Americans. Almost one-in four women and one in five men experience significant, persistent knee pain. Almost one in six older women and one in eight older men have hip pain almost every day. Knee or hip problems cut short the careers of many professional athletes and hamper regular activities for millions of others.

For many people, these problems become so intractable that the best solution is to replace a worn-out knee or hip with a mechanical joint. The average age for knee or hip replacement is the mid- to late 60s, although many people in their 80s and older gain pain relief and improved mobility from these procedures.

Physically, your knees and hips are closely interdependent, located as they are at either end of the thighbone. This proximity means the angle of your hip affects the pressure on your knee. A hip disorder may cause knee pain. And knee disorders can aggravate hip problems.

People live longer than they used to, and that means their joints need to stay strong and healthy through those additional years. Baby boomers expect to remain active and comfortable for eight decades or more. But both knees and hips are subject to repetitive trauma - wear and tea r-as you age, and you can traumatize them further if you try to be a weekend athlete or increase your physical activity suddenly.

Medical care has changed in recent decades. Doctors used to treat many knee problems by immobilizing the joint with a plaster cast. Weeks of immobilization caused the muscles to weaken and shorten, resulting in long-lasting stiffness and poor function. Today, you can wake up from surgery with your knee already being gently bent and straightened by a machine. In addition, knee and hip replacements have freed thousands of patients from life in a wheelchair or on crutches.

Surgical techniques have also advanced. More surgery is performed through tiny incisions using an arthroscope, often on an outpatient basis. Pain relief has moved away from mind-clouding narcotics toward an expanding variety of pain relievers that tackle the twin problems of pain and inflammation. Each year sees the development of more specific drugs with fewer side effects.

And finally, prevention has moved to center stage, alongside surgical repair and rehabilitation. More aggressive treatment of osteoporosis can reduce the risk of hip fractures. Better training practices for women help prevent common knee injuries, and more strength training added to your daily exercise routine helps support the joints and protect them from injury.