I have a physician with a tricky procedure. Can someone help?

About 6 months ago patient had a self inflicted gunshot wound to her femur. The surgeon she saw at the time placed screws in her femur to treat the fracture. She is now having pain and turns out one screw is broken and her femur is still nonunion. My surgeon went in and removed the screw that was broken and also did an open bone grafting. I think I can get the bone grafting taken care of but wondered if there was a code for the exchanging of the nail.

This patient also has Medicare if that makes any difference.

Thank you!