A surgical instrument for use with a robotic surgical system includes a knife blade configured to cut tissue and a knife tube coupled to the knife blade and configured to translate to move the knife blade for cutting tissue. The surgical instrument also includes a gearbox assembly coupleable to a robotic surgical system and configured to translate the knife tube to move the knife blade for cutting tissue and a knife blade lock operably coupled to the gearbox assembly. The knife blade lock is movable from a locked position wherein the knife blade lock prevents translation of the knife tube to an unlocked position in response to coupling of the gearbox assembly to the robotic surgical system wherein the knife tube is permitted to translate to move the knife blade for cutting tissue.