Parts of Dan Witkowski's feet, including the toes, already had been amputated last week to clear up an infection. In Friday's five-hour surgery, Dr. Douglas Smith amputated the young man's legs about 6 inches below the knees.
Doctors had previously told Witkowski, 25, he would probably keep his feet and be back on the slopes next winter. But there was more dead tissue due to frostbite near his heels than initially known, a spokeswoman at Harborview Medical Center said.
The prosthetics he'll now receive will be more stable than what was left of his feet and will offer him the best chance of skiing or running again.
"Dan's a very determined guy who wants to move on with his life," said the spokeswoman, Susan Gregg-Hanson. "He wanted that function and mobility, and to do that, he had to go with the amputation."
Witkowski's ordeal began New Year's Eve when, skiing solo, he plunged down an out-of-bounds chute at Alpental Ski Area, about 40 miles east of Seattle. He soon realized he was lost, and kept skiing and walking, trying to find his way back.
In reality, he was heading deeper into the backcountry, without food, water or survival gear.
By the fifth day, Jan. 4, Witkowski had lost 20 pounds and his temperature had dropped to 89 degrees. Rescuers in a helicopter spotted him and flew him to the hospital.
Witkowski was in satisfactory condition following the surgery. His recovery was expected to take 12 to 18 months. Smith estimated that he would be able to walk unaided within nine months.
One man who aided in Witkowski's search, Pierce County Sheriff's Deputy James Andrues, was killed Thursday while ice climbing in Canada.