Once in a great while I will run into a student at the AAOS Annual meeting. I would say that it is not worth your time and money. Most staff and residents are busy going from place to place mingling with their cohorts. It is like a class reunion. Most program directors are busy with symposiums, presentation, etc... There are no residency fairs that I am aware of.

I've been out to ORS/AAOS a few times as a medical student. I can say that unless you are presenting some research, it would be a big waste of time, energy, money to go there. The level of material was largely over my head, and only now that I have done some ortho rotations I am finally understanding what they were talking about. I've never seen a residency fair, and attendings/program directors are much too busy to talk with their friends, let alone a medical student they've never met.

Of course, if you are presenting, you should definitely go, as that is a great thing to talk about on interviews.