A surgical instrument includes an end effector, a handle assembly, a knife drive assembly, and a lockout assembly. The end effector includes a pair of jaws, a knife, and an RF electrode. The handle assembly includes a housing associated with the first jaw, and an arm associated with the second jaw. The arm is pivotably coupled with the housing and pivots the second jaw between the open position and the closed position. The knife drive assembly includes a trigger slidably coupled with the housing, an actuating assembly, and a return assembly. The actuation assembly converts proximal translation of the trigger into distal actuation of the knife. The return assembly automatically actuates the knife from the fired position to the pre-fired position in response to the trigger reaching a predetermined proximal position. The lockout assembly prevents activation of the electrode and distal actuation of the knife while in the locked configuration.
