An apparatus for joining two hollow organ sections with an annular array of staples includes a staple cartridge assembly, an anvil assembly, and a buttress assembly. The staple cartridge assembly includes a plurality of surgical staples in an annular array. The anvil assembly includes an anvil member and a shaft extending therefrom. The anvil member defines a plurality of staple pockets for deforming the staples. The anvil assembly is movable relative to the staple cartridge assembly between spaced apart and approximated positions to adjustably clamp tissue between the staple cartridge and the anvil assemblies. The buttress assembly includes a cut ring secured with the anvil member, a buttress member disposed in a superposed relation with the plurality of staple pockets defined in the anvil member, and a retaining member having an attaching member configured to be secured with the cut ring to secure the buttress member with the anvil assembly.