A surgical instrument end effector assembly includes a first jaw member defining an insulative tissue-contacting surface and first and second electrically-conductive tissue-contacting surfaces disposed on either side of the insulative surface. A second jaw member of the end effector assembly includes an ultrasonic blade body positioned to oppose the insulative surface of the first jaw member, and first and second electrically-conductive tissue-contacting surfaces disposed on either side of the ultrasonic blade body and positioned to oppose the first and second electrically-conductive surfaces, respectively, of the first jaw member. The first jaw member is movable relative to the second jaw member between a spaced-apart position and an approximated position to grasp tissue therebetween. The first and second electrically-conductive surfaces of the second jaw member are movable, independent of the first jaw member, relative to the first jaw member and the ultrasonic blade body between a retracted position and an extended position.