The Wales international does not yet know when he will go under the knife to solve the problem which has troubled him for most of the season.
Anfield manager Brendan Rodgers confirmed on Sunday the £15million summer signing from his former club Swansea was facing surgery and suggested the procedure would take place in the coming days.
And while Allen admitted the injury was a major setback, he insisted no date has been set for the operation and refused to use the problem as an excuse for his indifferent form during his first season on Merseyside.
He told Sky Sports News: "It requires another operation which is a bitter blow. These things happen in football, unfortunately, and it will keep me out for around three months when I do get the operation done.
"I'm not sure, to be honest (when the operation will be). That's something that is being decided and I will have to see what comes of it.
"I'm not looking to use it as an excuse. It's something that has deteriorated recently and it has got to a stage where an operation is all that can resolve it. I'm looking forward to getting it done, putting it behind me and moving on from there.
"It's not an ideal situation, but a player carrying an injury throughout the football season is part and parcel of the game and you come to expect it."
Oh dear, what will we do. Wish him well but he is very poor. His first touch is terrible (this actually applies to a few of our at the mo) and his passing and vision is simply not good enough for a midfield player. Steve- stevechase