(CNN) -- Austria's skiing ace Marlies Schild will miss the rest of the season after suffering a training accident, her national federation announced Friday.
The 31-year-old Schild, who is the reigning World Cup overall champion in the slalom, twisted her right knee ahead of a competition in Are in Sweden.
She returned home immediately after the fall on Thursday morning for further medical tests, which revealed a muscle tear.
A statement on the official website of the Austrian federation said she had undergone a short operation Friday which went well, but she would be sidelined for about three months.
"Marlies will start physiotherapy tomorrow," said Gernot Sperner of the Kettenbruecke clinic.
It is a bitter blow for Schild, who will be unable to defend her slalom title in the world championships in Schladming in February.
She is a four-time World Cup slalom champion and has also taken the combined overall crown.
Gold has eluded her in Olympic competition with two silver and a bronze medal her best performances.
Schild has been struck by injury before, breaking her left leg in October 2008 which sidelined her from competition for over a year.
In her absence in Sweden, 17-year-old American Mikaela Shiffrin won her first World Cup race under the lights at Are.
She finished 00.29 seconds ahead of Sweden's Frida Hansdotter, who was fastest on the first leg.
World Cup leader Tina Maze of Slovenia finished third.