My Mum had the op October last year, she was given Tramadol as pain relief. She certainly wasn't pain free by two weeks, she was a bit paranoid about becoming addicted to the Tramadol so tended to take one or two at night so that she could get to sleep. She did get a slight infection in the wound, but that healed up quickly with antibiotics. I think it took a good 6-8 weeks before she was fully mobile and totally pain free, but having said that a year on from the op she is like a new woman, the only problem being is she will probably need the other one doing in the near future as that is starting to give her some pain and will undo all the benefit of the new knee if it isn't replaced.