Using Grasshopper and Kangaroo on STL file

Hello all,

I am wondering if it is possible to apply rigging to a model that was previously created in Rhino. I didn't discover Grasshopper until recently. I am working with CT scans from bones and I want to simulate the motion of the bone's joints. What type of approach should I take to this? Other than simulating the motion, there would be actual numerical values I would be hoping to input into the simulation to receive some sort of output value.

I have seen how Grasshopper works to make something, but I didn't know if the plug-in would be able to be applied to a model that was already made.