Common practice is to leave the wires left in place. . Occassionally, when there is a problem the wires are removed. With most individuals, they can't see the wires or feel them. Broken wires probably should be removed as there is no useful purpose involved and may cause problems that you are experiencing.
That certainly doesn't sound right......unless removing them would be "dangerous". It sounds dangerous to me to leave them in.
I am 3 months out from aortic valve replacement and just found out that since this was my second sternotomy I have wires AND sternal plates.
Best of luck with your continued healing.