TUESDAY, Dec. 21 (HealthDayNews) -- Alternative therapies such as acupuncture and spinal manipulation may be worth a try to help relieve neck, back and knee pain.

That's the conclusion of a trio of studies that appear in the Dec. 21 issue of the Annals of Internal Medicine.

In one study of patients with painful knee arthritis, University of Maryland researchers compared acupuncture with sham acupuncture -- in which needles are inserted into points that aren't true acupuncture points. A third group received education sessions on arthritis management. The 570 patients were randomly divided to received either 23 sessions of acupuncture over 26 weeks; 23 sessions of sham acupuncture over 26 weeks; or six 2-hour education sessions.

After 26 weeks, the true acupuncture group experienced greater improvement than the sham group or the education group in both pain and function.

"This echoes the results of studies we have been doing for 11 years now," said study author Dr. Brian M. Berman, director of the Center for Integrative Medicine at the University of Maryland School of Medicine.

"The effect is not huge," Berman added, "but none of the things we do with osteoarthritis patients have a huge effect."

In the second study, Dr. George Lewith of the University of Southampton in England and his colleagues compared acupuncture versus electrical stimulation of acupuncture points in 135 patients with neck pain. The patients were evenly divided between the two groups. Acupuncture reduced the neck pain and produced statistically significant -- but not clinically significant -- effects, compared to mock acupuncture.

"Acupuncture is safe and effective for neck pain so it's worth trying," said Lewith, senior research fellow at the University of Southampton. "We need to do more big studies, but above all else we need to understand why such a safe treatment is so effective in the long term."

In the third study, which was conducted at several U.S. Army and Air Force bases, researchers examined 131 patients with low back pain who had been referred for physical therapy. They we re randomly assigned to receive either spinal manipulation with a physical therapist plus exercise, or exercise alone with a physical therapist for four weeks.

The researchers found the results depended on patient status at the start, as measured by common criteria such as the duration of symptoms, the patients' lumbar mobility, and how well they could rotate their hips. Those who met more of the criteria fared better, the study found.

The results are no surprise to Dr. Donald W. Novey, medical director of the Center for Complementary Medicine at the Advocate Medical Group at Lutheran General Hospital, in Park Ridge, Ill. "We use acupuncture for neck pain and there is a variation in response," he said.

"Some people respond wonderfully, some not at all," Novey said. In general, the older the patient and the longer the pain has persisted, the less effective the acupuncture.