Here's why:

* Strength: Stainless steel is strong and durable, able to withstand the forces placed on the sternum during healing.

* Biocompatibility: Stainless steel is well-tolerated by the body and does not cause significant reactions or rejection.

* Corrosion resistance: Stainless steel resists corrosion, which is important to prevent complications and ensure long-term stability.

While stainless steel is the most common material for sternal wires, other materials like titanium are also used in some cases. Titanium is also biocompatible and strong, but it may be preferred in individuals with known sensitivities to stainless steel.