Ortho is one of the most competitive fields right now in the civilian sector. It is usually very competitive in the Army as well. Last year, there were far less ortho applicants in the Army then usual, and almost everybody who applied received a position. But that is the exception, not the rule.
Army didn't fill all of their ortho slots this past year. Basically if you applied you got it unless your REALLY pissed off the residency director. The problem is probably going to become more prevalent since recruitment as a whole is trending down. Year to year is still going to be up and down based on the match population.