DEAR DR. DONOHUE: I am only 44, but I have to make a decision about having a hip replacement. I have very bad arthritis of my right hip. The doctor thinks it’s from an old football injury. I walk with pain. I shouldn’t say “walk”; it’s more of a hobble. The doctor has suggested hip replacement. How long do these things last? – V.B.

You’re not too young for a hip replacement if your arthritis is so bad that it makes you a cripple. In the early days of hip replacement, most patients were in their 80s.

That was due to the fact that the artificial hips of bygone years had a relatively short life compared with the artificial hips of today. Modern artificial hips can be expected to last at least 20 years.

As for your youth, 40 percent of hip replacements are done in people younger than 55.

The hip joint is a ball at the end of the thigh bone (the femur) that fits into a cup-shaped depression in the pelvic bone. In standard hip replacement, the ball of the femur and the socket of the pelvic bone are replaced.

The ball replacement is often a combination of two metals, chromium and cobalt. The socket replacement is a very durable plastic. In younger people like you, often both ball and socket are metallic, and the two metallic parts provide an even longer life.

A new modification of hip replacement is hip resurfacing. No bone is removed. The ball and socket are resurfaced by sanding them to get rid of irregularities. A metallic cover is placed over the newly polished ball, and a metallic cup is inserted into the newly polished pelvic socket.

This permits greater range of motion for the hip, and a patient with this kind of joint can take part in high-impact activities.

Not all centers in North America can provide this new technique, and it’s not applicable for all joint replacement surgery. You can ask your doctor about its availability in your area.

DEAR DR. DONOHUE: My doctor wants me to eat more fiber to help me get over constipation, and he suggests that I get some bran. I don’t have the foggiest idea what bran is. Can you buy it in a grocery store? – P.C.

Bran is the outer coat of grains. It’s the stuff that’s removed when grains are refined to make flour. I don’t know if all grocery stores have bran, but most health-food stores stock it. The recommended daily amount of fiber is 20 to 30 grams. Thirty grams is 1 ounce. A half-cup of wheat bran contains 12.5 grams of fiber.

You can’t eat bran straight out of the package. It’s not that palatable. You can sprinkle it on other foods, like cereal, or you can put it in baked goods.

Bran isn’t the only source of fiber. Vegetables, fruits and whole-grain products have a good supply of fiber. And if you want, you can get products like Metamucil, Fiberall and Perdiem that contain psyllium, another fiber source.

DEAR DR. DONOHUE: Can you explain what’s happening to me? I wake up with a line of pain and swelling that circles my stomach at about the beltline. Am I allergic to something ­- my pajamas or something in the bed? – H.L.

I put money on pressure urticaria. Urticaria is hives – in your case, the skin swelling.

Some people are sensitive to pressure on their skin and experience the kind of reaction that you do. The reaction takes place from three to 12 hours after the pressure is removed.

Antihistamines alone aren’t usually effective in preventing this from happening. A combination of an antihistamine with the asthma medicine Singulair can often put a stop to it.

Wait a minute. Don’t jump to medicines. Loosen your belt or wear suspenders.

DEAR DR. DONOHUE: Do migraine headaches result from a magnesium deficiency? I heard an infomercial on TV that said low levels of magnesium are responsible for migraines.

The commercial’s sponsor just happened to be selling a product that contains magnesium. Would it be worth my while to send for it? – R.P.

ANSWER: Some studies have shown that magnesium can block migraine headaches in a few people. It’s not a universal antidote for all migraine headaches, and not many, if any, migraine specialists believe that all such headaches are due to magnesium deficiency.

The daily magnesium requirement for women 31 and older is 320 mg and for men of the same ages, 420 mg. If you want to try a supplement that doesn’t exceed those requirements by very much, it would be safe to experiment.

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475. Readers may also order health newsletters from

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