although there are indeed plenty of categorical gen surg spots available after the match, that really isn't the best route to take. Besides the obvious fact that any gen surg spots that are open are open for a reason (terrible location, bad reputation, etc), once you accept a gen surg spot that program is depending on you being there for 5 years. They will NOT be happy if you try to dump them after one year. Considering you'll need their permission to interview, letters of recommendation, and time off to interview, you don't want to have your boss pissed at you.
A better idea is to apply to, or scramble into, preliminary surgery spots. Those programs recognize you are just there for 1 year and plan to move on afterward. It's also understood that if you work your butt off and make nice with everyone there in both the surgery and ortho departments that you'll have a nice "in" at the ortho program when you apply. The best prelim spots are usually gobbled up through the match, but there are still fortunately enough leftovers for everyone.