He was outstanding in the Canadian team's run to the championship. He was co-leader of the team in scoring, finishing the seven games tied with another great defender, the New York Islanders' Denis Potvin, with nine points. Orr was selected to the tournament All-Star team and capped the experience with the most valuable player award.
Orr's performance at the Canada Cup had the Chicago faithful energized for his first appearance in colours other than Bruins black and gold. But Orr's left knee would once again impede his career. He played 20 games of his first season in Chicago weakened by his sixth operation on the knee in April 1976. He spent the entire 1977-78 season recuperating, trying to revive his battered knee, which doctors described as nothing but bone rubbing bone after so many operations and injuries.
He made a valiant attempt to return, playing six games at the start of the 1978-79 season. Though Orr didn't feel incredible amounts of pain, he was limited in his movements and unable to practise much with the team. In one game against the Detroit Red Wings, he was on the ice for four Detroit goals and described his play as "terrible." At the age of 30, he decided he was only hindering his Chicago squad. Howard Cosell, the legendary sportscaster, announced in October 1978 that Orr had retired, though it later turned out he had mistaken Orr for Bobby Hull, who was also contemplating leaving the game. A few days later, Orr called Cosell and told him he was indeed retiring and asked him to attend the press conference. Cosell refused, jokingly saying that he didn't "cover old news."
Because of his continuing problems, Orr had never collected a paycheck from the Black Hawks. He said he was paid to play hockey, and after his retirement he accepted a reduced salary to become an assistant coach, a position he had filled while sitting out the year before.
Orr was inducted into the Hockey Hall of Fame in 1979. He worked frequently with charities in the coming years and maintained close links with the game. He later became an agent, helping young players benefit by sharing his difficult early experiences through the business side of the sport.
from the Hockey Hall of Fame