Thomas Einhorn, Boston University School of Medicine orthopedic surgery department chairman, has been performing some revolutionary surgeries — and there are no bones about that.

During the past year, Einhorn, a Rutgers University and Cornell University medical school alumnus, has used stem cells in several surgeries, the first of which he completed in July 2007. The patient in that surgery, who had previously undergone a total hip replacement, had not healed properly from the first operation.

“When you put the artificial parts into the hip joints, the bone has to grow into it to stabilize it,” Einhorn said. “The surface is somewhat porous, and the bone grows into those pores. In this particular patient, this didn’t happen on his previous operation.”

The operation Einhorn performed to fix the problem involved coating the artificial hip with stem cells. He said, contrary to popular belief, this operation was not designed to regenerate a large segment of bone. Instead, the surgery stimulated bone formation within an area where bone already existed.

Since the operation’s first attempt was a success, Einhorn has recently followed up with one more of its kind, and three more stem cell surgeries of a different nature. Einhorn performed these surgeries on patients who had a condition causing dead bone in the hip.

“I’ve taken their stem cells, injected the cells into the area where the bone is dead, the cells that I’m injecting would form bone in the area and replace the dead one,” he said

Einhorn’s surgical procedures may be difficult to understand out of context. George Muschler, the pioneer of the operation, said stem cells heal any fractures people receive during their lifetimes. Stem cells have the ability to make new bones.

“The reason that all fractures don’t get healed automatically is that sometimes there’s such severe trauma to the area that the stem cells don’t survive because their blood supply has been cut off or the environment is not conducive for the cells to make bones,” Muschler said.

Medical efforts in stem cell surgeries for bone production have been given a new level of attention, Einhorn said.

Einhorn said being a professor has become intertwined with his research and the clinical work he is involved in because he does not lecture. Students spend anywhere from two to six weeks with Einhorn and his colleagues, during which they are exposed both to the clinical work and information at conferences.

“Medical students will do clinical rotations, and we actually teach them hands-on clinical skills in orthapaedic surgery during the time that they rotate with us,” he said.

Cory Edgar, a resident in Einhorn’s training program, completed his doctorate work under Einhorn’s mentorship. Edgar said he enjoys working with Einhorn, and has learned a great deal from him.

Einhorn’s future goals include further exploring the potential role of molecular medicine in his orthopedic surgeries, and he is currently working with part of a $5.5 million program project grant from the National Institutes of Health for stem cell research.