an orthopaedic aid for an extremity includes at least one adjustable element for positioning the orthopaedic aid relative to the extremity . the detector arrangement includes a plurality of indicators for indicating torques generated by the detector arrangement . the detector arrangement is positionable such that a section of the detector arrangement is torque - free . the detector arrangement generates torques arising in two opposite directions in a measuring plane in response to deviations from a stable load position .