Femur Biopsy

I recently had an MRI of my knee because of ongoing swelling and pain. I have a history of PVNS (a benign aggressive soft tissue tumor) that I had radiation (8yrs ago) for because it was so diffuse through my knee and aggressive. My MRI now is showing a 2.2cm tumor in my lower femur near my knee. They are not sure what it is (reoccurrance of PVNS, Sarcoma or Osteonecrosis) My doctors are planning a biopsy of that section of bone. I have appt monday to discuss everything. I need to know what to expect! Anyone who has had a biopsy of femur please help! I also have brittle bones so I think that also may complicate things a bit.

1) Is it done in operating room?
2) How much pain?
3) Crutches? Cast?

Thanks for your help!
Jen