Dara Torres knew she needed surgery on her ailing left knee. She didn't expect a radical operation and a recovery of up to 18 months.

The 42-year-old, five-time Olympic swimmer told The Associated Press on Thursday she will have the reconstructive procedure Oct. 20 in Boston. Her shinbone will be broken to create more room for cartilage to grow around her kneecap.

While admitting she's a bit "freaked out" about having such a major operation, Torres said it could actually give her more motivation to come back for the 2012 London Olympics. She won three silver medals at the Beijing Games, but failed to make the top three at this year's world championships in Rome.