A forceps includes a housing having a shaft extending therefrom. The shaft has an end effector assembly that defines a longitudinal axis therethrough. The end effector assembly includes first and second jaw members disposed in opposed relation and moveable from a first, open position to a second, closed position for grasping tissue therebetween and a knife. One or more jaw members include knife blade channels defined therein. Each knife blade channel includes a polygonal longitudinal cross-section defined therein. The knife includes a knife edge and a knife base. The knife base includes a corresponding polygonal longitudinal cross-section. The knife is configured to translate through the knife blade channels and the knife base is configured to slidingly engage the knife base channel having the polygonal cross section upon translation of the knife. In embodiments, the knife blade channel and the knife base have a T-shaped longitudinal cross-section.