A surgical instrument includes a body assembly and a selectively coupleable end effector assembly. The end effector assembly may include a transmission assembly, an end effector, and a rotational knob operable to rotate the transmission assembly and the end effector. The body assembly includes a trigger and a casing having a distal aperture configured to receive a portion of the end effector assembly. First and second coupling assembly portions cooperatively couple the end effector assembly to the body assembly for use. An attachment assembly may be used to rotatably couple the first and second coupling assembly portions.