ESPN Radio was talking about it throughout the game, wondering if it had affected his performance. I later heard that he needed a shot in the back of the knee before the game to reduce the swelling. Everyone is saying that he'll pitch Game 5, assuming the Astros win at least one before then.
I know Pettitte said it didn't affect him, but after hearing what they had to do to it, I find that hard to believe. He was leaving the ball up a lot, and wasn't using his offspeed pitches much. I don't know how his knee would effect those two things, but he definitely did not seem to be pitching his game last night.