Adherence concepts for non-woven absorbable felt buttresses

A loading unit (16) for use with a surgical stapling apparatus (10) including a tool assembly (17) and a surgical buttress (B1, B2). The tool assembly includes: a cartridge assembly (18, 118, 418) including a staple cartridge (82, 182, 482) having a tissue facing surface , staple retaining pockets (82a) having a plurality of surgical fasteners (84) therein, and a knife slot (82c, 182c, 482c); and an anvil assembly (20, 120, 220, 320, 520) including an anvil plate (70, 170, 270, 370, 570) having a tissue facing surface defining staple forming pockets (70a) and a knife slot (70b, 170b, 270b, 370b). The surgical buttress is attached to the tissue facing surface of at least one of the cartridge assembly or the anvil assembly, and conforms to the tissue facing surface such that the surgical buttress is deformed locally into the staple retaining pockets and the knife slot of the cartridge assembly or the staple forming pockets and the knife slot of the anvil assembly to which the surgical buttress is attached.