If your knees ache and creak, you've got lots of company. At least a quarter of everyone over age 55 has had a significant problem with knee pain in the past year. Usually the cause is osteoarthritis, a breakdown of the joint cartilage that also causes damage to the bone beneath. There's no cure, which leaves ample room for hope, hype, and halfway measures.
Glucosamine, which is made from shellfish, and chondroitin, which is made from cow cartilage are being used every day by millions of Americans — including, reportedly, President Bush. The supplements supposedly work by rebuilding cartilage. Most doctors have had a tolerant attitude about this. Conventional medicine doesn't have any sure thing. Knee replacements are major surgery and a last resort. If supplements don't do any harm, why not give them a try?
No better than placebo
But doing no harm doesn't mean doing any good, either. The National Institutes of Health (NIH) is running several popular supplements through the gantlet of large clinical trials. The NIH-funded Glucosamine/chondroitin Arthritis Intervention Trial, or GAIT, included 1,583 people with symptomatic knee osteoarthritis. The researchers randomized them to take the supplements in various combinations or placebo pills, and then asked the volunteers to grade their knee pain six months later. The results showed no difference between the placebo pills and glucosamine and chondroitin.
Some experts say the door is still ajar because a subgroup analysis showed some benefit from the supplements among people with more severe cases of osteoarthritis. But subgroup analyses are inherently suspect because the number of subjects involved gets small, and positive findings may occur just as a matter of chance. There's also some question about the glucosamine compound tested in the trial and whether it has the same effect as the glucosamine sulfate now being sold.
Also, as with the results of every study, what's true on average may not apply to everybody. There are individuals who swear by the relief they get from glucosamine and chondroitin. While that could be just a placebo effect, it may be true for some.
Bowlegged and knock-kneed
The natural alignment of our knee is to be a little knock-kneed (valgus). But we have a tendency to fall out of alignment, so we end up bowlegged (varus) or more knock-kneed than we should be.
These malalignments can cause a vicious cycle. You may start out with just a little bit of malalignment but have an otherwise normal knee. If you're varus, that malalignment may cause a little divot in the cartilage on the inside of the knee, but the outside space opens up. You get more malaligned, which causes more load on the inside of the knee and more damage to the cartilage.
What can you do?
Wearing a good pair of running shoes is a good place to start even if you aren't a runner. Running shoes are made to accommodate either pronation (rolling on the inside of the foot) or supination (rolling on the outside).
You can buy those knee supports made of stretchy material that fit over the knee like a sleeve. They may help give you some added stability.
You can also buy over-the-counter (OTC) orthotics that fit into your shoe. They can help if you have a mild case of osteoarthritis. But orthotics can make foot and ankle problems worse. In short, they may be worth a try, but you have to be sure that they aren't aggravating your problems.
You can buy OTC knee braces, but it's better to get one through a doctor after your knee problems have been properly diagnosed and analyzed. Design has improved, but they're still bulky, and may not fit under a pant leg.
Try to find a doctor, regardless of his or her specialty, who can help you with bracing or exercising, or give you a referral to a physiatrist (a doctor who specializes in rehabilitation) or a physical therapist who will.
Exercise: Pain is not gain
Exercise is crucial, but it can make knee osteoarthritis worse if you're not careful. To be effective, strengthening exercises should be gradual and not provoke greater knee pain. Getting a knee brace, orthotics, or both to correct malalignment before you start an exercise program may make a difference.
Exercises shouldn't put too much weight on the knee. For that reason, pool workouts are ideal. Biking may be another option. Ideally, your exercise program should be custom-made under a doctor's supervision.
June 2006 update