I'm not a physician. If your question is really this general (asking about math without focusing on an area) and also specific (focusing on ortho surgery, as opposed to gp, etc) then you might need to post to a med forum, and maybe you can find even an ortho forum.
But just for example, all med students are required to have taken calculus before entry into med school. Now are all docs doing power series in between patients? Probably not.
But when you are trying to get into a specialty like ortho, its likely you are going to have had done research before getting in, at least in the more competitive programs. Research is pretty well expected in many levels of the sciences for advancement these days, and its in areas like this where the harder core mathematics and physical sciences often come into play. Even in an area like biology, you often need to cross over to other fields like chem or mathematics to do meaningful research.
I'm sure there needs to be some understanding of instrumentation design and function... and with the computer navigation systems that are out today ill bet the tech info can get heavy.
An aside - ever look at the harvard surgical planning site. One of my all time fav med sites. Especially when they start doing things like PET overlayed on an MRI... a geek thing I guess, but its powerful imagery.
http://splweb.bwh.harvard.edu:8000/
When my wife had her laser eye surgery her doc measured her on three diff occasions to make sure his instruments would be set correctly. I'm sure there are many of the same concerns when you're talking about ortho. Again, I don't know if you call that math. Its not a quadratic eq or differentiation, but number based.
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