Kettering University's biodegradable magnesium alloy can repair traumatic bone injury

Repairing traumatic injury to a bone is possible, but current procedures require multiple surgeries and long-term recovery. Kettering University's Dr. Montserrat Rabago-Smith and her team of co-researchers are exploring the use of a magnesium orthotic alloy in severe trauma injuries where the distance between two halves of a bone can't be overcome by the human body's ability to regenerate and heal.

Kettering researchers are trying to develop a magnesium alloy material that is biodegradable and requires only one surgical procedure to assist the bone in healing over the "magic" distance. "A magic distance is two times the width of the bone that is damaged," explained Rabago-Smith, assistant professor of Chemistry/Biochemistry at Kettering.

Magnesium alloy was chosen as an orthopedic biomaterial for its bioresorbable properties. Its mechanical properties are similar to natural bone, making it appropriate for load-bearing orthopedic fracture repair applications. The strength and density of Magnesium and Mg alloys match those of bone while also being stronger than bone.

"Our alloy, Mg AZ31, is shaped like a tube and coated with a substance that helps to control the degradation of magnesium alloy," she said. The tube shape was designed in an effort to reduce the amount of alloy used for implantation in a shape that mimics cortical bone shape.

The hollow cylinder acts as a scaffold for bone re-growth, she explained. The scaffold is coated with different amounts of the coating developed by Rabago-Smith and her colleagues, showing a slowed corrosion compared to non-coated scaffolding.

"Magnesium is very reactive by itself, especially in the presence of water where the reaction occurring is oxidization, like rust," said Rabago-Smith. The coating protects the patient, but degradation does occur. However, degradation is gradual and slow, like a long-term fish pellet, giving the body time to generate new bone. "Our scaffold facilitated new bone growth across the magic distance," Rabago-Smith said.

Rabago-Smith and her colleagues are still in the process of studying the coating and improving the process. Their goal is to improve bone growth and develop a biodegradable material. It is still not appropriate for use in humans, she added.