American skier Lindsey Vonn on Friday said she has had surgery after breaking her right arm while training in Colorado.

In a post Friday afternoon on her Facebook page that included X-ray images, Vonn, a four-time overall World Cup champion, said she "severely fractured the humerus bone in my right arm" after a crash at Copper Mountain on Thursday and that she hopes to return to skiing "as soon as possible."

"I had successful surgery last night in Vail and everyone took great care of me," Vonn wrote. "While I am beyond frustrated by this latest setback, at least my knees are ok and I will return to the slopes as soon as possible, as I always do!"

Vonn also wrote on her Twitter account, "I don't know why these things happen to me but I know I am a fighter and I refuse to let it bring me down! I will never give up!''

In February, Vonn, 32, suffered three significant breaks near her knee joint during a super-G crash in Andorra. She tried to keep skiing, only to end her season a few days later. At the time, she was thinking long term -- toward the 2017 world championships in St. Moritz, Switzerland, and the 2018 Winter Olympics in South Korea.

Vonn has been steadily healing and was tentatively hoping to be back for the World Cup races in Lake Louise, Alberta, in early December.

Now, with her latest injury, there's no timetable for her return to the start gate.

Over the years, Vonn's list of injuries has been long. She hurt her knee in training and missed two races at the 2007 worlds. She also raced with a severely bruised shin at the 2010 Vancouver Olympics when she won the downhill. But she couldn't defend her crown four years later in Sochi because of a serious knee injury.

She broke her left ankle in New Zealand during training camp before last season. In November 2015, Vonn needed stitches in her right thumb after trying to break up a fight between her dogs over a Frisbee.

Through all the adversity, Vonn became the winningest female World Cup racer with 76 victories. She has closed the gap on the career mark of 86 victories by Ingemar Stenmark of Sweden.

Information from The Associated Press was used in this report.