A treatment that uses medical cement to fix cracks in the spinal bones of elderly people worked no better than a sham treatment, the first rigorous studies of the popular procedure show.

Pain and disability were about the same up to six months later.

The treatment is so widely thought to work that the researchers had a hard time getting patients to take part when it was explained that half of them would not get the real thing.

“All of us who do the procedure have seen apparently miraculous cures,” said Dr. David Kallmes, a radiologist at the Mayo Clinic who led one of the studies. But he said there were also “miraculous cures” among those who got the fake treatments.

The researchers said it is yet another example of a medical procedure coming into wide use before good studies are done to show that it is safe and effective.

About 750,000 Americans suffer painful compression fractures in the spine each year. Bone-thinning osteoporosis is the most common cause. There are about 80,000 bone cement procedures done in the United States each year, Kallmes said.

Medicare pays $1,500 to $2,100 for the procedure.

The findings were published in today’s New England Journal of Medicine.