Dunne initially suffered the setback when part of the Republic of Ireland's Euro 2012 campaign.
He underwent early season surgery and had to undergo a further operation after returning to training last month.
Now the former Manchester City player has again gone under the knife in the hope it will finally bring an end to his spell out of action.
Villa manager Paul Lambert said: "Dunny got hurt at the Euros and it's never really cleared up. I think that's where it's come from.
"He had another operation yesterday in America so hopefully once and for all that will be cleared up.
"I think America was the only place he could get that done. He'll come back in the next few days and hopefully then start his rehab and get going again.
"It's all stemmed from his hip area.
"We tried to sort out one thing and then it went to another, then it's gone to another thing. I've never seen anything like this. I don't think the medical people have seen anything like this."
Lambert insists Villa have not looked at trying to obtain compensation from the Football Association of Ireland over the matter.
He said: "I've not gone down that road. Injuries can happen to players, sometimes you get to the bottom of it, sometimes it takes longer than you think.
"As a footballer you get frustrated because you can't put your finger on what's gone wrong with you. Hopefully this time this has worked."
Lambert is hoping a sickness bug at Bodymoor Heath this week is under control ahead of Saturday's clash at Liverpool.
He said: "There are one or two who have not felt too good. I hope it is not too bad.
"Stephen Ireland missed the Norwich game with it. He came in yesterday and did a little bit so we will see how he is feeling again before the Liverpool game."
Lambert refused to speculate on whether striker Darren Bent's hamstring injury will have any bearing on the future of the player ahead of January's transfer window.
Bent made his first start for six weeks in the Capital One Cup quarter-final at Carrow Road in midweek but limped off after half an hour.
He is now facing "a few weeks" out of action and has been ruled out of the festive programme.
Lambert said: "I thought he looked sharp considering he hadn't played for a number of weeks. He had a good chance to score.
"The thing with Darren is he gets into those positions where he can score. It's just unfortunate that he made a run and he has done something to his hamstring.
"Could it affect what happens to him in January? It is what it is. We just concentrate on the games coming up.
"I've not said that (what might happen) one way or another. It's just unfortunate we have a player who is injured."