A cartridge of a surgical instrument includes a housing, a lead screw mounted for rotation in the housing, a drive member operatively coupled with the lead screw, and a knife member. The knife member is driven distally by the drive member and is configured to cut when moved distally. During an initial distal movement of the drive member, the knife member is coupled with the housing to restrain the knife member from moving distally. Subsequent to the initial distal movement of the drive member, the drive member drives the knife member toward the distal end.