WWE updated their story on CM Punk here on dot com. The WWE Champion underwent arthroscopic surgery on his left knee under Dr. James Andrews. The procedure was done to train a cartilage tear in Punk's knee.
Below is an excerpt from their update:
“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.”
In an update from my sources, I noted it was believed the procedure was a minor scope.