Ask the Doctors January 2007 Issue

Ask The Doctors 01/07

Iím interested in the heel strike factor in weight bearing exercise. Since I have osteoporosis, I can no longer jog and have been looking for low-or no-impact activities. I understand that swimming does not promote bone density.

Weight-bearing activities stimulate our bones to react by increasing bone density. The term "weight-bearing" means your bones are working against gravity to support your body weight or, in the case of weight lifting, other weight. So walking, running, push-ups, using an elliptical machine (and anything else done on your feet) and weight lifting are weight-bearing exercises.

Swimming, though it is wonderful for flexibility and cardiovascular fitness, does not place any significant stress on the bones.

Although research has suggested that walking is not as beneficial in building bone as jogging, a recent study found that the risk of hip fracture was lowered by 41 percent by walking at least four hours a week. Some research has linked regular yard work to the prevention of osteoporosis, finding that women age 50 and older who gardened at least once a week developed higher bone density than those who performed other types of exercise including jogging, walking, and aerobics. So, while you may not be able to jog, there are plenty of options to maintain bone density.

I have rheumatoid arthritis and have been told that steroid injections can control my inflammation. Steroids, Iím told, can also be taken orally. Which is most effective?

Rheumatologists try to keep patients with RA off oral steroid agents (glucocorticoids, not anabolic steroids as used by some athletes). These agents are effective at controlling inflammation, but they have too many side effects if given for long periods of time. These side effects can sometimes be as serious as the disease itself and include weight gain, osteoporosis, diabetes, cataracts, bone necrosis, muscle weakness, and heart disease. Sometimes oral steroids must be used, and the dictum is to prescribe as low a dose as possible for as short a time as possible.

Injections of steroids into a joint can help quell inflammation and are not associated with any of the side effects listed above. As a general rule, no more than two to three injections are given in the same joint per year.

Iíve had pain behind my knee for more than 20 years. Iím now 77 and the pain is getting worse. Iíve seen several orthopaedic physicians, but so far no one has been able to help. Can you tell me what causes the pain behind my knee?

Without a thorough physical examination, itís difficult to determine the cause of posterior knee pain. The soft tissues and tendons around the knee are the most common sources of posterior knee pain, but other causes may be vascular or neurologic. Your osteoarthritis may itself be a cause of the pain.

A common cause of posterior knee pain, especially in individuals with osteoarthritis, is a Baker cyst, which is swelling caused by knee joint fluid accumulating in the back of the knee. This excess fluid usually is caused by an inflammation of the knee joint, such as with arthritis. A Baker cyst can be asymptomatic for many years before it gradually becomes more and more painful. If your doctor diagnoses a Baker cyst, treatment of the underlying cause is the first option. Direct treatments include physical therapy, fluid drainage, and corticosteroid injections. Sometimes, particularly in patients with osteoarthritis, the cyst may not go away. If it continues to cause pain and interferes with your ability to bend your knee, surgery may be considered, however rarely, to remove the cyst.