Vickers says he believes his study confirms the value of acupuncture for treating chronic pain, even if he detected only a modest difference between real and fake needle therapy. He notes that some studies suggest that fake, also called “sham,” acupuncture may elicit an unusually strong placebo response, which could have the effect of diminishing the apparent benefits of true acupuncture when the two are compared. Also, it’s possible that sham acupuncture may actually trigger production of pain-blocking chemicals. “Just putting an acupuncture needle in the body, even if it is not at a true acupuncture point, likely has some physiologic effect,” writes Vickers in an e-mail.

Other researchers aren’t so sure. A 2010 review of 12 studies by scientists at the University of Maryland found that six months of real acupuncture produced “clinically irrelevant improvements in osteoarthritis pain” when compared to sham acupuncture. (The few studies that have examined acupuncture for rheumatoid arthritis have had generally disappointing results.) While practitioners of traditional Chinese medicine, or TCM, say that precisely placed needles heal disease by influencing the flow of energy known as chi in the body, few Western-trained physicians embrace that belief, and there remains no accepted scientific explanation for how acupuncture might work.

Questions about acupuncture’s mechanism and whether it really eases pain leave many doctors reluctant to recommend the treatment to patients.  “In my opinion, it’s a placebo,” says rheumatologist Donald M. Marcus, MD, of the Baylor College of Medicine. Dr. Marcus was coauthor of a study (included in Vickers’ meta-analysis) that found no difference between acupuncture and sham acupuncture; it was published in Arthritis Care & Research in 2010. Some people may feel better after receiving acupuncture, Dr. Marcus concedes. “But it’s expensive and the effects are transient,” he says. “The relief may last a while, then you’re back to square one.”

Other doctors, including Dr. Avins, agree that acupuncture’s benefits may be due largely to the placebo effect – yet still feel it could be worth trying. Growing research suggests that placebos – whether fake needles or sugar pills – may prevent pain signals from reaching the brain and promote other biological changes that could relieve symptoms of OA and other conditions.

“If I’m suffering chronic pain and someone offers me an intervention that will improve my symptoms, I’d be thinking: Of course I want that,” says Dr. Avins. “As a patient, I just want to feel better … If our ultimate goal is to help patients achieve their goals, the mechanism is not all that relevant.”

Intriguingly, recent studies suggest that some patients may respond well to placebos even if they know they’re receiving an inert treatment, notes Dr. Avins.