Q. I'm 65 and have had knee pain for years. What about glucosamine, joint injections or surgery?

A. Though glucosamine is widely used, studies are mixed. A New England Journal of Medicine study of 1,583 folks with knee osteoarthritis, the wear-and-tear thinning of the cartilage that is the likely cause of your pain, found that glucosamine and chondroitin sulfate, alone or in combination, did not reduce pain compared with fake drugs, called placebos. But some folks do seem to benefit from the combination.

A systematic review found that steroid injections into the knee were of only short-term (one week) benefit. Injections of hyaluronic acid, a lubricant, may give longer pain relief but are likewise of only temporary benefit.

But both acupuncture and capsaicin cream have been shown in randomized studies to work. Capsaicin, made from chili peppers, is available without a prescription and is applied 3 to 4 times per day. The 0.025 percent concentration is better tolerated than the 0.075 percent one, but be patient — it may take three to four weeks to start to work.

If you continue to suffer bothersome knee pain, talk to your doctor about knee replacement surgery, which, per the National Institutes of Health, is a safe treatment resulting in rapid and substantial improvement in pain and quality of life in 90 percent of patients; 85 percent of patients are satisfied with the results of surgery. However, only 1 in 10 people who qualify for this surgery actually do it — the rest have excuses like "it hurts like hell, but then I'm fine for a couple of months."

The June 2008 issue of Chest updated its widely used guidelines on preventing leg blood clots from surgery, which could otherwise cause a largely untreatable postthrombotic syndrome with chronic leg pain, swelling and skin ulcers. Without blood thinners, 2 to 7 percent of knee replacements would also cause dangerous clots that break off and go to the lungs (pulmonary embolism). Compliance with the Chest guidelines among orthopedists appears higher than other surgical specialties — 90 percent in recent surveys.

Aspirin and/or intermittent pneumatic leg compression aren't good enough. Poor compliance, patient intolerance and inability to be used at home limits the usefulness of the latter. The usual patient should instead be on a minimum of 10 days of one of the blood thinners Lovenox, Arixtra or Warfarin. A Cochrane review, published Oct. 8, found that adding one of these to leg compression reduced symptomatic pulmonary embolism to 1 percent compared with 3 percent with compression alone.

Yes — any surgery has risks, but don't lose the chance to live your remaining years in less misery and more independence.

Dr. Landis Lum is a family- practice physician for Kaiser Permanente and an associate clinical professor at the University of Hawai'i-Manoa John A. Burns School of Medicine. Send your questions to: Prescriptions, Island Life, The Advertiser, P.O. Box 3110, Honolulu, HI 96802; islandlife@honoluluadvertiser.com; or fax 535-8170. This column is not intended to provide medical advice.