Ivica Kostelic will not ski again this season after tearing knee ligaments in Tuesday's World Cup slalom.
Kostelic has been dogged by knee problems during his career
The Croatian had surgery in Basel on Wednesday which saw ligament from his quadriceps transplanted to repair torn cartilage in his right knee.
He will remain in hospital until next Thursday and will be out of action for between three and five months.
Kostelic also injured his shoulder in the fall in Schladming, Austria, but did not need further surgery.
Kostelic tore his knee ligaments four times between 1997 and 2001 and underwent keyhole surgery after his win at Madonna di Campiglio last month.
His sister, Janica, will also miss the rest of the season after having surgery on her thyroid gland. She left hospital on Monday.