A tubular string having a box end and pin end coupled to one another with a threaded attachment and a coupling assembly. The coupling assembly includes an annular outer thrust ring having an axial end abutting a shoulder on a terminal end of the box end. Included with the coupling assembly is an inner thrust ring, which is also annular, and which has an end that axially abuts a shoulder formed along an outer surface of the pin end. An alternate type of the inner thrust ring is made up of two separate semi-circular members that circumscribe the pin end when positioned in the recess so their arcuate ends adjoin. The inner thrust ring inserts into the outer thrust ring, and has a radial surface on its outer circumference that lands on a shoulder formed along an inner circumference of the outer thrust ring.