A surgical instrument is designed for clamping, cutting, and/or joining tissue. This surgical instrument includes a handle portion, an elongate portion extending distally from the handle portion, first and second jaw members disposed adjacent a distal portion of the elongated portion, a shaft movable upon actuation of the handle portion, and a knife bar operatively coupled to the shaft. At least one of the jaw members is movable with respect to the other between an open position and an approximated position for engaging body tissue therebetween. The knife bar has a curved profile and moves along at least one of the jaw members upon movement of the shaft.