Updated statement from WWE.com:
WWE.com has confirmed that Dr. Andrews completed a scope of CM Punk’s left knee. Andrews successfully trimmed a cartilage tear in Punk’s knee.
“CM Punk underwent knee surgery today to remove a piece of torn meniscus that had locked up his knee,” said Andrews’ colleague, WWE physician Dr. Chris Amann. “The surgery, performed by Dr. James Andrews, went smoothly and CM Punk is expected to make a full recovery.”
We don’t have a confirmation at this time if Punk will miss the TLC PPV in two weeks on 12/16 as a result of the surgery on Tuesday afternoon.