I don't think a medium grain rice will work. Here's what I have: "choose short-grained round or semi-round rice; among the best rices for making risotti are Arborio, Vialone Nano, and Carnaroli. Other short-grained rices such as Originario will also work. Long grained rice such as Patna won't do, because the grains will stay separate."
But never tell a person not to do something, because they will.