News_

Metal plates and screws no longer required for fractures

15 January 2018

Successful implants in sheep speed trials of new ceramic scaffold

A new 3D-printed ceramic implant developed by biomedical engineers at the University of Sydney will ultimately replace grafts and metal hardware in mending broken bones using the body’s natural healing process.

Millions of people worldwide suffer bone loss due to injury, infection, disease or abnormal skeletal development.

The new implant developed by Professor Hala Zreiqat and her multidisciplinary team based in the Faculty of Engineering has the same strength as real bone and dissolves over time without discomfort or need for further surgery.

Professor Zreiquat’s team have already demonstrated that the new material can completely heal broken arm bones in rabbits. Now, in work about to be published, they have shown it can also repair large leg fractures in sheep.

The eight sheep in the study were able to walk on the implants immediately after surgery, with plaster casts helping to stabilise their legs for the first four weeks.

Results showed complete healing in 25 per cent of the fractures after three months and 88 per cent after one year.

A natural alternative

"The bone substitute we have developed resembles natural bone in terms of architecture, strength and porosity,” says Professor Zreiqat.

“By allowing blood and nutrients to penetrate the supporting material, normal bone growth is encouraged which will eventually replace the gradually dissolving scaffold.”

The sheep involved in the trials tolerated the implants well, with no evidence of toxic side effects as the implants dissolved.

The “ink” the team used in the 3D-printing process was a mixture of calcium silicate, a mineral called gahnite, and small amounts of strontium and zinc that are found as trace elements in bone.

Current structural supports such as metal plates and screws can cause the patient discomfort, and bone grafts are often rejected by the patient’s immune system.

Because the synthetic scaffolds have a similar composition to real bone, the body can’t tell the difference.

Professor Zreiqat

Better supply to meet growing demand

Each patient only has a limited amount of bone available for grafting making the demand for synthetic bone substitutes high.

The unique ceramic material being developed by Professor Zreiqat’s team will also solve this growing problem worldwide.

Human trials are the next step, starting with the repair of spinal defects and broken jaws before testing the scaffolds on larger fractures in load-bearing bones in the legs and hips.

"This material has the potential to positively affect the quality of life of millions of people globally, so we are hoping to see it in use clinically within the next 10 years.”