i'm only a fourth year med student..don't even know if i'm gunno match - just so you know where this opinion is coming from!
whole package - really varies with different programs. But in general, good board scores, AOA or at least honors in medicine and surgery, some kind of research exposure (ortho not necessary but helps a little) -> this will get you in the door. Now probably the most important thing is to do a away rotation at a program you REALLY want to go to, and blow them away - work hard, be nice, and hopefully you "fit in".
No such thing as a minimum board score - that being said, to be competitive and get interviews outside of where you rotated and home school, i have read around 230+. Your usually not in great shape but not hopeless if your 220+ at your home school and STRONG away places. People definately match below these scores so don't put to much weight on this, thats just what I MYSELF have felt to be an average to put in the good shape.
In all honety, FMG might be an issue - I would be lying if I said it doesn't matter. This is due to a couple of reasons - so many US grad people apply into ortho, I think programs feel obligated to those. Also, if there are visa issues - ortho people HATE paper work - so thats an issue. I have seen foreign grads in good programs - but they usually do a few years of research at a place to "prove" themselves and can usually get in. Its more of a challenge definately but a total possiblity for someone motivated to work hard.
Hope that little bit helps - pray for me so I match (weird how we all become spirtual when things are at stake!)
Peace