LONDON (AP) — Lindsey Vonn's ski season is over.

The overall World Cup leader said Wednesday she was leaving the racing circuit early because her left knee injury was more serious than originally thought.

Vonn crashed on Saturday in a super-G race in Andorra after catching a spot of soft snow. X-rays showed a hairline fracture and the American raced Sunday in the combined event, extending her overall lead by finishing in 13th place.

But she said Wednesday there was not one hairline fracture, but three more significant fractures.

"After the super combined on Sunday, I went to Barcelona where more precise MRI and CT equipment was available and scans were performed on Tuesday morning," Vonn said in a statement on her website. "Those images showed that there was not just one hairline fracture, but in fact three. And the fractures are not hairline, but instead they are significant enough that they are not sufficiently stable to permit me to safely continue skiing."

Because of the results of the tests, the four-time overall champion said she decided to end her season immediately, calling it "one of the toughest decisions of my career."

She said any further damage could hurt her chances of skiing in the future.

"With the world championships in St. Moritz next year and the Winter Olympics in South Korea the following year, I cannot take that risk," Vonn said.

With eight races to go, Vonn leads the overall World Cup standings with 1,235 points, followed closely by Lara Gut of Switzerland with 1,207. Viktoria Rebensburg of Germany is third with 914.

"It's a real shame that the tense fight for the overall title can't last until the end," Gut said in a Swiss ski federation statement. "I wish Lindsey Vonn a good recovery and a successful return next season."

Men's overall leader Aksel Lund Svindal was also ruled out for the season with a right knee injury from a crash in January in Kitzbuehel, Austria.

Vonn has won nine races this season after a hampered preparation. She missed the season-opening race in October after a 10-week layoff because of a broken ankle bone, a year after coming back from the injuries that kept her away from the 2014 Sochi Olympics.

In Cortina, Vonn won a downhill to eclipse Annemarie Moser-Proell's mark of 36 career wins in skiing's marquee event. She then won a super-G for her 11th career victory at the Italian resort, breaking the record of retired Austrian standout Renate Goetschl.

"While I am confident that I'm making the right decision," Vonn said, "it still doesn't make this decision any easier."