During the following months, Orton was put in the orbit of the WWE United States Championship. He defeated the champion Bobby Roode at Fastlane (thus becoming the 18th Grand Slam Champion) but lost it at WrestleMania 34 against Jinder Mahal in a fatal four-way match also involving Roode and Rusev. He had another title match at Backlash against the new champion Jeff Hardy, but Orton lost again. On May 18, WWE confirmed that Orton had undergone successful surgery to repair a medial meniscus tear in his left knee, sidelining him indefinitely.