I am a current third year hoping to get some advice from those who have gone through the application process. I am wondering which programs required supplemental information (in addition to ERAS)?
Do a search in previous posts for "special requirements" and "application requirements." This has been discussed previously.
The best thing to do is to decide what programs you are applying to and then use FREIDA to link to each programs website. All of the websites detail what their application requirements are. It is a bit of a bear to do, but the best way to insure that you meet all of the requirements at each program you apply to. In addition, use other applicants from your home program that are going into ortho as a resource - you can split up the work if you want to. Just my two cents.
Off the top of my head, Washington University, University of Washington, and Yale have supplemental evaluation forms for your LOR writers. A bunch of other programs require a chairman's letter, some others require bizarre things like your MCAT / SAT scores.