Orthopedic product maker Synthes Inc. handpicked surgeons and paid for the doctors' travel to training sessions where company employees explained how to use their new bone-mending cement to fix a type of spinal fracture that afflicts hundreds of thousands of people yearly, most of them elderly. Federal prosecutors alleged in an indictment of the company that these training sessions were a dangerous, illegal, and less expensive substitute for clinical trials required by the Food and Drug Administration. Synthes has said it acted properly and will defend itself against the charges.