According to the Captain, "at about 11,000 feet, we received a call from our flight attendant, who stated that she was injured. She said that when she stood up from her flight attendant seat after 10,000 feet and was making her way back to the galley she slipped and fell. I inquired if she could still perform her duties, at which point she said that she could not. I proceeded to call dispatch and notified him of the incident and told him that we would return to the airport and he concurred. I requested medical assistance and after [I] did a passenger briefing about the incident and that we were returning to CVG." According to the Flight Attendant, she got out of her jumpseat after 10,000 feet to begin service. As she proceeded to the galley, she slipped and fell. The flight attendant said there was glycol on the floor, and she must have slipped on it. She had difficulty getting up. A passenger seated in 2A was able to assist her into seat 1A. Another passenger came forward and identified himself as a family physician and offered assistance. He had her apply ice to her ankle and got the interphone for her so she could notify the Captain. The flight attendant informed the Captain that she could not continue to work the flight. The captain made the decision to turn around and go back to CVG instead of continuing onto GSP. The captain made an announcement advising the passengers that she was injured and unable to continue and they would be returning to CVG. After landing, the Emergency Medical Service met the aircraft and carried the her off the airplane. The passengers then deplaned back into the terminal. At the hospital, the flight attendant said the doctor informed her that her leg was broken in three places.