A shape sensing system includes a guide tube (304) and an optical shape sensing device (104) including one or more optical fibers and being proximally fixed at a fixation point and being disposed within the guide tube. An interventional instrument (102) is rigidly attached to a handle (212) to prevent rotation of the instrument relative to the handle. The instrument has a lumen configured to receive the guide tube therein such that the optical shape sensing device is unconstrained throughout the instrument and the handle, and the guide tube is free to slip relative to at least rotation of the instrument and the handle without transferring torsional friction to optical shape sensing device.