I can only say : Learn to create bones, and animate on MED.
It's not easy, there are some very good tutorials.
And once you get it, it's fast as hell.

You can't compare MED bones and animations to Blender.

I don't see the interest to bring the model from MED to Blender.Otherwise, you must export from MED to a file format
where Blender will import the animations !
MED is limited in file formats, and i'm not sure it have one
that do that.