An adapter assembly includes a cam housing defining a proximal cam slot and a distal cam slot, a first elongate shaft, and a second elongate shaft. The first elongate shaft has a proximal end portion received in the proximal cam slot, and a distal end portion configured to be coupled to a surgical loading unit. The second elongate shaft has a proximal end portion received in the distal cam slot, and a distal end portion configured to be coupled to the surgical loading unit. The first and second elongate shafts are configured to move in opposing longitudinal directions in response to a rotation of the cam housing to articulate the surgical loading unit.