An electrosurgical instrument includes an end effector comprising two movable jaws for grasping tissue therebetween. The jaws connect to an electrosurgical energy source to deliver energy through tissue between the jaws to effect a seal. The jaws include a knife channel to reciprocate a knife there along for severing tissue held between the jaws. A two-stage articulation joint is coupled to the end effector and to articulation bands configured to articulate the end effector. The two-stage articulation joint includes an outer cut metal tube comprising a plurality of sections and a solid but flexible inner core positioned within the outer cut metal tube. The electrosurgical instrument also may include a rotatable closure ring and a closure link operatively coupled to the rotatable closure ring, a rotatable coupling joint coupled to the articulation section, and/or a hollow flexible tube coupled to the knife and an active rod extending longitudinally therethrough.