George W. Bush undergoes second knee surgery

George W. Bush on Saturday underwent a partial knee replacement in Chicago, his second since Memorial Day weekend, the former president's spokesman Freddy Ford confirmed to CBS News.

The outpatient procedure at Rush University Medical Center's Midwest Orthopaedics successfully restored Mr. Bush's left knee. His right was partially replaced in May.

"It's remarkable what they can do now," Ford said. "He walked up and down a flight of stairs just a couple hours after the surgery."

Ford said Mr. Bush, who with his wife Laura left the Windy City on Monday morning for Dallas, is looking forward to getting back on his mountain bike in several weeks' time.

Since vacating the White House in 2009, the 43rd president has publicly prided himself on fitness, immersing himself in aggressive cycling challenges. Still, his health has become something of an ongoing storyline: Last August, he underwent a heart procedure after it was discovered he had a blocked artery.

Mr. Bush will enjoy some moral encouragement as he recovers. Cashing in on the soaring unpopularity of President Obama, the Republican National Committee is continuing its fundraising pitch marketing t-shirts emblazoned with the slogan, "I MISS W."