I'm a current Canadian orthopaedic resident who spent time in the US so let me try and clarify.
To be eligible for orthopaedic residency training in Canada, you must be a Canadian permanent resident or citizen. The only exceptions I know of are:
1. McGill has one spot per year for US citizens that do not have Canadian resident/citizen status.
2. Some programs have training arrangements with a few (primarily Middle Eastern) countries to train their residents. These are funded by the home countries' governments and you must be nominated by that country. These programs have been cut back substantially in the last 5-10 years, at least in ortho.
The length of residency training is the same as in the US - 5 years. There are a few programs that have 6 year options with an intercalated Master's degree, although you apply for this track once you are already a resident in the program.
There is no requirement in Canada to do 2 years of fellowship. However, many folks do two years to be more marketable (especially if they want to practice in a bigger city or in academics), since the ortho job market is more competitive as compared to the US. Doing a fellowship in Canada as a Canadian tends to be more financially rewarding as compared to the US, since in most programs you bill directly just like any board-certified specialist.
In my program, you do 6 months ortho/6 months off-service in each of the 1st two years. Then all ortho. I imagine others are broadly similar since these things tend to be mandated by the Royal College of Surgeons. That being said, you are considered an ortho resident from the 1st day (no separate internship per se) so you attend all the ortho half days etc starting in 1st year.
Going to the US is not a problem. Canadian training is fully recognized and very well regarded in the US, and there are many private practice and academic attendings in the US who are Canadian board certified (look for the initials FRCSC - Fellow of the Royal College of Surgeons of Canada). However, to work/do a fellowship in the US you must complete all steps of the USMLE, and get the appropriate work visa if not American. You don't need ABOS to do fellowship in the US, although I think most insurance companies will want you to have it once you start working independently?
Canadian residency training is of uniformly high quality. Unfortunately, because of the way our health care system is structured, it is really only accessible to Canadians.
Hope this helps.
