The popular 31-year-old defender, who joined the Premier League club from AC Milan in 2004, said he could not really believe he was sitting in front of journalists announcing his decision.
"It is so weird, so strange sitting here making this announcement that I am not going to be able to play football anymore," he said.
"Five months ago I was flying, I was on top of my game," he added.
"But I can't recover from my injury - so I've got to retire. I've spent a while making up my mind, thinking about things. Deciding whether I wanted to go ahead with an operation and see if I could come back or whether I should retire.
"It would have been a big and difficult operation. At this point, I think it's better for my health and future life to say: 'That's it.'
"The retirement of the lionheart defender will be a huge loss to the players, the manager and the fans," a statement on Villa's website said on Friday.
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