An adapter assembly of a surgical instrument includes a cam member defining a proximal cam slot and a distal cam slot, a first articulation shaft, and a second articulation shaft. The first articulation 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 articulation 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 articulation shafts are configured to move in opposing longitudinal directions in response to a rotation of the cam member to articulate the surgical loading unit.