Dorgu, 21, sustained the injury during United's 3-2 win at Arsenal in January — the game in which he scored a stunning curled finish and in which Michael Carrick's first month in charge culminated in one of the club's most significant results of the season.
He had scored in each of his first two matches under Carrick, netting the second goal in the derby win over Manchester City before his Arsenal effort, and his absence had been keenly felt over a 13-game stretch in which United had no natural left-sided option.
He posted a brief message on Instagram to mark the moment.
"I am happy to be back and in good shape. All praise to God."
The return came at an apt moment. United's 3-2 victory over Liverpool sealed Champions League qualification for next season, completing the primary objective Carrick had been set when appointed in January.
Dorgu came on as a substitute in the 75th minute, replacing Bryan Mbeumo, and played the final quarter of an hour as United held on for a result that sent Old Trafford into celebrations.
The Denmark international made 46 appearances across all competitions for United before the injury, scoring three goals and providing four assists. His contract runs until 2030 and he is expected to play a significant role in what is shaping up to be a heavily altered squad next season, with multiple departures anticipated in defence.