DEAR DR. DONOHUE: I’m beginning to get little knobs on my finger joints. I believe this is arthritis, and I have seen it in the advanced stages. What can I do to prevent it from getting worse? -- Anon.

ANSWER: The knobs on the finger joints below the fingernail are Heberden’s nodes, named after an English doctor who died at the start of the 19th century. Knobs on the middle finger joints are Bouchard’s nodes, named after a French doctor who died in the early years of the 20th century. Both of these knobs are signs of osteoarthritis -- the common kind of arthritis, the kind that most seniors have at least a touch of. They’re similar to bone spurs seen on backbones and other bones, another consequence of osteoarthritis.

Osteoarthritis comes from fraying of the cushioning cartilage inside joints. How extensive or how incapacitating it will be is unpredictable. Most people manage to get along in spite of it. However, it can be a great burden to others.

There is no preventive medicine to stop osteoarthritis in its tracks. It has a predilection for the fingers, hips, knees and spine. Should it strike larger joints like hips, knees and backbones, muscle strengthening will serve you well. Strong muscles protect joints. The exercise should not be so vigorous that it causes pain, but it should be vigorous enough to encourage strength building. Being overweight increases the stress on knees and hips, so you should strive to stay on the lean side.

Many people swear to the effectiveness of chondroitin and glucosamine, both of which are available without a prescription, and often they come in combination. Not a lot of evidence exists to endorse them wholeheartedly, but if you want to give them a try, they won’t hurt you.

The arthritis booklet deals with osteoarthritis, also called degenerative arthritis. Readers can order a copy by writing: Dr. Donohue -- No. 301W, Box 536475 Orlando, FL 32853-6475. Enclose a check or money order (no cash) for $4.75 U.S./$6 Canada with the recipient’s printed name and address. Please allow four weeks for delivery.

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DEAR DR. DONOHUE: For quite some time, my right shoulder has hurt. I saw an orthopedic doctor, who says I have a tear of my rotator cuff. He suggested surgery. What do you think of surgery for this? I am scared that I could be worse off after the operation than I am now. I am only 44 and am quite active. -- K.M.

ANSWER: The rotator cuff is a band made up of the tendons of four back muscles. The tendons wrap around the topmost part of the upper arm bone, the humerus, to keep the bone in the shoulder socket. Tears of the rotator cuff are a common problem and one of the principal causes of shoulder pain. Small tears can heal on their own. Larger tears almost always require surgical correction. All surgical procedures demand respect. Something can always go wrong. Most people who have had surgery to correct a rotator cuff tear are glad they had it. By most, I mean more than 95 percent. I would not hesitate to have this surgery.

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DEAR DR. DONOHUE: What causes hangnails? I have a crop of them. I know this isn’t a pressing medical question, but what can you recommend to prevent them? -- L.B.

ANSWER: Hangnails form when the skin dries. Dry skin at the borders of the nails cracks to form a hangnail. Prevention comes from the daily use of moisturizers.

Even though it’s tempting to pull a hangnail off, don’t. Cut it with small, sharp scissors.

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DEAR DR. DONOHUE: Please explain what complex carbohydrates are. I see this term on all diet instructions. I don’t have a clear idea of what it means. What makes them complex, and how are they healthier than other carbs? -- W.L.

ANSWER: Carbohydrates are starches and sugars. Fruits, vegetables and most grains (flours) are carbohydrates.

Complex carbohydrates are long chains of carbon molecules. Starches are complex carbohydrates. Sugars are simple carbohydrates. Complex carbohydrates don’t raise blood sugar as quickly as do simple carbohydrates, so they don’t provoke a great demand for insulin.