A surgical device comprises an elongate shaft comprising an outer tube and an inner rod positioned in the outer tube, the outer tube and inner rod each comprising a distal end and a proximal end. An actuator is operably connected to the proximal ends of the outer tube and the inner rod. An end effector is adapted for in vivo attachment to and detachment from the distal ends of the outer tube and the inner rod, the end effector comprising a collet for locking engagement with the distal end of the inner rod. The end effector may further comprise a second collet for locking engagement with the outer tube. The surgical device may further comprise a loader comprising a collet for locking the end effector in the loader.