Vertebroplasty, a common spine operation in which medical cement is injected into a fractured vertebra(脊椎)to stabilize it, worked no better than a sham(見せかけの、模造の)treatment in the first major study of the popular procedure. About 750,000 Americans endure painful compression fractures(骨折)in the bones of the spine each year, sometimes suffering debilitating(衰弱させる)pain, limited mobility, and a loss of height or a stooped posture(姿勢)as a result. Of these, tens of thousands undergo vertebroplasty, perhaps unnecessarily, as researchers now believe that those who receive a fake treatment experience the same improvement as those who have the real thing.