Not as much of a disadvantage as you may origionally believe. If you go onto
www.aacom.org there is a brochure and on page 54 it lists the breakdown of a survey taken as to where D.O.'s are doing their residencies. So I will tell you that there may be some fuzzy math going on here. On the website it shows approximately 9.3% of all AOA residents are Ortho residents (about 240), but your chances of landing an ACGME residency are awful at around 0.4% (about 24 overall, this is considering the fact that 2/3's of D.O.'s end up doing ACGME residency). These numbers should be taken with a grain of salt, but if you add up the total Ortho residents in the survey and divide by the total number of residents you end up around 3.2% (which is also not 100% accurate since every residency takes a different number of years). Lets just say it is 3.2% for the sake of this discussion, that is compared to 4-5% of all M.D.'s in practice that are orthopods.
IMH-premed-O, I don't think that you should go apply to medical school with the intention on becoming an orthopod only. What happens if you get in and do not have the grades for it (it is probably the most competitive field)? Nor do I think that you should avoid going to an Osteopathic school simply because you think that you have a better shot at becoming an orthopod at an allo school. Good luck and I hope you find my post useful.