An interface joint for integrating into a single cable assembly all of (i) a fluid feed, (ii) a needle movement mechanism, and (iii) an energy feed (e.g. a coaxial cable). The interface joint may be used with an electrosurgical instrument for applying to biological tissue RF electromagnetic energy and/or microwave frequency EM energy. Also disclosed is a torque transfer device for permitting controlled rotation of the cable assembly within the instrument channel of an endoscope. The interface joint and torque transfer device may be integrated as a single component.
