You can absolutely get a prelim position with those scores. Heck a lot of prelim spots go unfilled every year.
Like I said, you're put yourself in good position with your usmle scores...they will only help you. What you do from here is up to you...I think research in ortho and publications would help more.
You have to make a decision and it's a hard one:
1. do you apply for ortho now AND for a prelim year...if you get ortho great. if you get the prelim, that means you cannot do ortho research for another 2 years (not counting this year)...and after that you'd mostly be relying on an ortho position opening up (like someone dropping out)...it's a risky move and it could back fire if nothing opens up.
2. You apply for ortho only now...if you get in fine. But in case you don't, you get involved in ortho research full time at a place where you can get a lot of exposure to multiple well-known attendings...you get a few publications, get meaningful research experience but it has to be something that is significant and that would catch the attention of an academic-minded chairman. You do this for 2, maybe 3 years and in the meantime each year you apply for ortho. You have to make a living too, so maybe you should try to find a research position that pays you like 20-30 K.
It's a hard choice...and it's risky and a big time investment if either does not work out. But if you want ortho bad, if I were you (not saying you should do this, just that this is what I would do knowing myself)...I would choose route 2 above and bust my rear end getting pubs and exposure so you really impress the living *^%&# out of'em.
good luck to you.