European Journal of Cardio-Thoracic Surgery
Cause:The synergic effect of stress and poor wire quality could be the precursors of material failure for the sternal wire.
Results: All examined fractured wires showed the presence of severe transversal cracks and crevice corrosion. EDAX revealed aluminum oxide inclusion on the fractured surface.
Sorry for the gender confusion. The other post states it is the husband with the problem, and I assumed Bigfella was the husband asking the question. Because the operation was fairly recent, the integrity of sternum has not been compromised. It takes a long time to heal, so it requires good binding.
You may want your wife to verify there has been proper healing of the sternum. Some people ignore a broken wire and some find it bothersome and have it removed.