BOSTON (WHDH) -- Six-year old Bella, a border collie, faces a “ruff” recovery after a first-of-its-kind surgery.

Bella seriously injured her leg falling off furniture three months ago. But thanks to landmark muscle transplant surgery performed at Angell Animal Medical Center in Boston, she can go for walks again.

“The leg was actually pulled back to the side. The dog had triceps muscle -- which are the muscles right behind the elbow and above the elbow area-- that were damaged and contracted that was pulling the leg backwards,” said Dr. Michael Pavletic, Angell Animal Medical Center.

Dr. Michael Pavletic, the head of surgery at Angell, was able to transplant muscle from Bella's back to her front leg and then trained the muscle to do the work of a leg muscle.

“It’s not common. We’ve used other muscles for reconstructive surgery in veterinary medicine and certainly human medicine as well. This was, I think, one of the first for almost complete replacement of the triceps muscle,” Dr. Pavletic said.

After a long recovery process, Bella continues to improve. Her leg is operating just as well as before her tumble.

“You want to initially restrict excessive activity and do very light physical therapy; two weeks or so. Then you’d expect enough connective tissue is present so that you can start more formal physical therapy and strength training,” Dr. Pavletic said.

Bella will continue with her physical therapy at the medical center. Doctors say her prognosis is excellent.