A surgical stapling apparatus, comprising: a housing, a handle supported by the housing, an elongated body extending distally from the housing, a tool assembly supported at the distal end of the tool assembly, including a staple cartridge a surgical buttress releasably secured to the staple cartridge by an anchor, a drive assembly for firing staples from the staple cartridge, and a knife blade pivotably mounted in a distal end of the staple cartridge, a knife blade insert disposed in the staple cartridge to maintain the knife blade in a first condition, proximal to the anchor.
