Question: I report hip core decompression with bone grafting with an unlisted-procedure code. Is this correct? Kentucky Subscriber Answer: Yes. You should report 27299 (Unlisted procedure, pelvis or hip joint) to describe this procedure. Tip: You won't find a designated code for knee core decompression either, but remember that you should look to unlisted knee-procedure code 27599 (Unlisted procedure, femur or knee) for this procedure.