BOSTON — Andrew Bynum said today he was “100 percent sure” he would play in Game 5 of the NBA Finals on Sunday. Bynum said his injured right knee was much improved after he had fluid drained from it Friday morning. He also underwent an MRI exam, which showed there was no further tearing of his meniscus. He played only 12 minutes during the Lakers’ loss to the Boston Celtics in Game 4, scoring two points and grabbing three rebounds.