An interface joint 120 for interconnecting an electrosurgical generator and an electrosurgical instrument comprises a housing with an outlet 146 and a slidable trigger 135 on the housing. A single flexible cable assembly 154 is connected to the outlet and integrates a fluid feed 150, a push rod 130 for moving an electrosurgical implement and a coaxial cable 126 for conveying RF and/or microwave energy to the electrosurgical implement for cutting and coagulating tissue. The slidable trigger is attached to the push rod and a reinforcement element (248, Fig. 10C) is coupled to a first portion of the push rod to reinforce it. The reinforcing element is preferably in the form of a support tube fixed to the first portion of the push rod. Additionally or alternatively, the interface joint may include a slide limiting mechanism (Fig. 10B) coupled to the push rod and configured to limit a maximum slide distance of an internal tube (238, Fig 10B) over the push rod by means of a stopper (244, Fig 10B).
