Ask Dr Gary: Action oils' creaky knees

I was having knee problems last year. My doctor took x-rays and told me I had pre-arthritis in my knees. He recommended glucosamine and exercises like lunges to strengthen my quads. I've been doing both, and my knee pain is almost gone. I'd like to stop one or the other, but I don't know which. Any advice?

- Terry, Whangarei

There are no definitive answers on glucosamine. The results from scientific studies have been all over the place. Early studies showed it was great for osteoarthritis, the most common form of arthritis, brought on by old age and wear-and-tear. But most of those studies were paid for by glucosamine manufacturers. Later, independent studies often found no benefit.

The latest big review, in the 2010 British Medical Journal, came down strongly against glucosamine, saying it was ineffective and should not by used by doctors, nor funded by government agencies, as a treatment for arthritis.

I don't feel too strongly about it, except to say that the most striking thing about these studies, to me, was their placebo effect. Sugar pills normally show modest effectiveness, because people taking pills for their pain usually feel better, even if the pills don't actually have any active ingredient. Perhaps this is due to motivation or positive thinking, or just hope. But, in many of these joint pain studies, the placebo rates were huge. In some, the sugar pill reduced pain by 20 to 50 per cent. What this suggests is that chronic arthritis pain is very sensitive to our frame of mind, our perspective, our motivation, our hopefulness. It makes it hard to tease out the effectiveness of glucosamine, when even a fake pill can have such massive (albeit short-lived) effects.

Oh, and one other thing. We know that inactivity worsens stiffness and pain in arthritis. Exercise stimulates joint lubrication, and has been shown to reduce pain. If you must drop one thing, don't drop the exercise.