Darren Fletcher has spoken of the dark days of the illness that required make-or-break surgery to save his career, but the midfielder now believes he is "back for good".

Fletcher made a first appearance for Manchester United since Boxing Day as a 70th-minute replacement in Sunday's 3-0 win at Aston Villa, having recovered from ulcerative colitis, a debilitating bowel condition. The illness has plagued Fletcher for the past two years, with him first having to take a break from football in December 2011. He made a return in September of last season but managed only 13 outings before, after all other treatments had failed, opting to have surgery in a final bid to save his career.

Asked if there had been dark days, Fletcher said: "Yes. That was ultimately the reason I went for the operation. There were days when the illness was getting the better of me. I couldn't leave the house. I couldn't take my kids to the park. Simple stuff. I couldn't go for a meal with my wife, just because of the nature of the illness. There was the exhaustion side of it as well. It was proving difficult. I always had a belief that one of the medications would work. Unfortunately that wasn't the case.

"There was always the option of surgery. I had to be ready for it. Ultimately, that day came. There were no guarantees with the operation. Fortunately I had a fantastic surgeon – Professor Sagar – without him I would not be here today. I have made a comeback in the Premier League. I made the decision at the right time and it has all worked out.

"If the operation was not a success there was no way I would be able to play football. My everyday life would be very difficult if it wasn't a success. I had to be mentally prepared for the challenge. It was tough. It was two or three operations not just one. It is psychologically challenging dealing with the operation as well but I couldn't live my life at all. I needed something done. That made the decision easier. I got the option of it 18 months to a year before I eventually got it. At that time there was still a chance of me making a recovery or finding the medication that worked. I went through all the solutions but eventually there were none available."

Fletcher drew strength from his determination to play for United again. "I am always thinking about football," he said. "I know people will say I should think about other things – and I was thinking about my children, my wife and family – but right there, right beside it was football. I worked hard to be a professional footballer. I was doing this operation, not just to have a quality of life but also to get back playing football."

Now, following the three separate procedures Fletcher no longer has the illness. "I do not have ulcerative colitis," he said. "I have come through that now. I am leading a normal life. It has all been a success. I am just like anyone else."

Fletcher can remember the moment when he believed the nightmare was finally over. "Yes. There was a day in about May when we said: 'This is it.' Once I came out of that operation it was going to be: 'This has either worked or it hasn't,'" he said. "It was a very emotional day. There was a lot of fear and anxiety and a lot of buildup. I was in the hands of an unbelievable surgeon. I put all my trust in him. He was confident, as long as I did everything right. He was confident all the tests were right. He was fantastic. That moment came. It was such a relief."

Having managed only 28 appearances for United and Scotland over the past two seasons, Fletcher can focus on being permanently available. "I'm back for good. This is hopefully the game which means I'm back now. Hopefully there will be no setbacks with the health issues. I seem to have come through that, thank God. It's onwards and upwards."

United's win was their first in the league since early November to end a run of two draws and two defeats. The champions are 10 points behind Arsenal and seven behind Manchester City, who occupy the final Champions League berth, as David Moyes's side travel to Stoke City for Wednesday evening'sCapital One Cup quarter-final.

"We have got to get to the semi-final of the League Cup and go on a run and be in contention come new year,"Fletcher said. "We have to be in a position where it is still possible. That is all we can do now. It has to be a winning run, not an undefeated run. We need to get back to going on winning runs and put ourselves in a position where people are saying we are still there. It is dangerous for everyone else if we are still there."