In one embodiment, a force sensor apparatus is provided including a tube portion having a plurality of radial ribs and a strain gauge positioned over each of the plurality of radial ribs, a proximal end of the tube portion that operably couples to a shaft of a surgical instrument that operably couples to a manipulator arm of a robotic surgical system, and a distal end of the tube portion that proximally couples to a wrist joint coupled to an end effector.