An endoscopic instrument includes a housing having shaft. The shaft includes an articulating section disposed thereon. An end effector assembly operatively connects to a distal end of the shaft and is configured to treat tissue. A plurality of tendons operably couples to the articulating section and is translatable along a longitudinal axis to effect articulation of the shaft about the articulating section. Each of the tendons includes a respective locking ferrule disposed thereon. A locking catheter is disposed within the shaft and between the plurality of tendons to selectively engage each respective locking ferrule. The locking catheter is rotatable within the shaft from a first position to allow articulation of the shaft about the articulating section, to a second position to prevent articulation of the shaft.
