An end effector actuation system includes a shaft assembly having an outer shaft with an internal lumen and an actuation rod slidably received in the lumen, the outer shaft having a distal end portion that is compressible only when the actuation rod is absent from the lumen in the distal end portion, a locking boss provided on the distal end portion; and an end effector assembly having a receiving opening and a retention pocket, wherein the receiving opening is sized to receive the compressed distal end portion of the outer shaft and the retention pocket is sized to receive the locking boss when the distal end portion is uncompressed due to the presence of the actuation rod in the lumen of the distal end portion.