Vicky Balch, 20, who was injured in the Alton Towers Smiler rollercoaster crash on 2 June, has had her right leg amputated below the knee after seven rounds of surgery.
She is the second victim to have had a leg amputated. Leah Washington, 17, had her leg amputated above the knee days after the crash. Other riders on the Smiler ride which crashed into an empty carriage, had sustained serious leg injuries.
Balch's lawyer Paul Paxton said: "Vicky has had a long and incredibly painful fight to retain her leg. Regrettably her bravery has not been rewarded.
"The step was taken to remove the leg following seven bouts of surgery. Further surgery will be required in the immediate future, which may involve a more acute amputation."
Balch was sitting in the front of the carriage together with Washington, Joe Pugh and Daniel Thorpe when the accident took place.
A total of 16 people were injured in the collision. So far eight of the victims have received interim payments to help with their rehabilitation, according to the law firm representing them.
Merlin Entertainment which owns Alton Towers, has said that it has contacted the injured and that all 16 will receive compensation.
In her first interview after the crash, Balch told the BBC that her only thoughts during the agonising four-and-a-half hour wait before she was freed was that she would not survive.
"It felt like slow motion. We banged into the car in front. I felt the bars go into my knees; we moved backwards and the car went into us again," she told the BBC.
"I passed out. I was awoken by [fellow passenger and boyfriend] Dan shouting my name. Everyone was screaming and I was in excruciating pain. I looked down and I could see blood all over. The bars were in my right knee.
"The only thought that was going through my mind for the hours and hours that we were stuck was that we were going to die. If I was going to survive I would never walk again, that was certain. I thought it was never going to end. I just wanted to die."