I remember responding to a query about this issue in the past, but I can't remember when that was nor what I said exactly at that time. For what it amounts to, the patient in question sustained a femoral fracture of some type that was treated with ORIF, apparently with plate and screws. I am not certain why the Lag Screw had to be replaced, but in addition to that some of the screws in place had to be tightened as well. So, in essence this was a limited "Revision" of the original ORIF, which of course doesn't have a code. I don't think 20680 does this case justice as to the work done. My "current" thinking would be to use the original ORIF code with Modifier 52: Reduced Services.
Maybe this will help.
Respectfully submitted, Alan Pechacek, M.D.