An annular rotary knife blade for rotation about an axis of rotation (R') in a power operated rotary knife , the rotary knife blade comprising: an annular carrier portion including a first end and an axially spaced apart second end , an outer wall and a radially inward spaced apart inner wall extending respectively between the first end and the second end , the carrier portion including a set of gear teeth and a knife blade bearing surface ; an annular blade portion including a first end and an axially spaced apart second end , an outer wall and a radially inward spaced apart inner wall extending respectively between the first end and the second end , and a cutting edge at the blade portion second end , the blade portion configured to be received in a nested relationship by the carrier portion such that a portion of facing surfaces of the outer wall of the blade portion and the inner wall of the carrier portion are in contact within an overlap region of the blade portion and the carrier portion ; and an attachment structure for releasably securing the blade portion to the carrier portion , the attachment structure including a plurality of projections extending from one of the outer wall of the blade portion and the inner wall of the carrier portion and a plurality of sockets disposed in the other of the outer wall of the blade portion and the inner wall of the carrier portion , each of the plurality of projections being received in a respective different one of the plurality of sockets to releasably secure the blade portion to the carrier portion , wherein, if the plurality of projections extend from the outer wall of the blade portion , the plurality of projections are spaced from the first end and the second end of the blade portion , and, if the plurality of projections extend from the inner wall of the carrier portion , the plurality of projections are spaced from the first end and the second end of the carrier portion . an annular carrier portion including a first end and an axially spaced apart second end , an outer wall and a radially inward spaced apart inner wall extending respectively between the first end and the second end , the carrier portion including a set of gear teeth and a knife blade bearing surface ; an annular blade portion including a first end and an axially spaced apart second end , an outer wall and a radially inward spaced apart inner wall extending respectively between the first end and the second end , and a cutting edge at the blade portion second end , the blade portion configured to be received in a nested relationship by the carrier portion such that a portion of facing surfaces of the outer wall of the blade portion and the inner wall of the carrier portion are in contact within an overlap region of the blade portion and the carrier portion ; and an attachment structure for releasably securing the blade portion to the carrier portion , the attachment structure including a plurality of projections extending from one of the outer wall of the blade portion and the inner wall of the carrier portion and a plurality of sockets disposed in the other of the outer wall of the blade portion and the inner wall of the carrier portion , each of the plurality of projections being received in a respective different one of the plurality of sockets to releasably secure the blade portion to the carrier portion , wherein, if the plurality of projections extend from the outer wall of the blade portion , the plurality of projections are spaced from the first end and the second end of the blade portion , and, if the plurality of projections extend from the inner wall of the carrier portion , the plurality of projections are spaced from the first end and the second end of the carrier portion . <EOS>