The Republic of Ireland international signed for the Hoops on a free transfer this summer, following a final season at Aston Villa where he failed to feature once due to fitness problems.
Dunne, 34, has confessed that he did think about quitting football during his time on the sidelines, but now acknowledges that the tough road to recovery was worthwhile after settling in quickly at Loftus Road.
He told reporters. "I ended up going to America for another operation which eventually fixed what was wrong but after the operation I tore the whole muscle again, the abductor.
"That was another 12 weeks which was eventually the whole season, it was disappointing. I was never told at any stage that I would be out for 14 months or so. I was told I'd be alright in six weeks or be alright in eight weeks, but unfortunately it never worked out.
"It [giving up] does cross your mind. My physios kept me going and they were confident that eventually they would get it right. You get bad days when you think I can't see this getting better. It took a very long time but it's worth it now to be back playing."
Dunne is part of the Championship's tightest defence, with Rangers having only conceded seven goals in their 14 league fixtures this season, in which they have kept nine clean sheets.