3D printed alloys can match stiffness of bone

Date: June 13, 2019

Orthopaedic surgeons are accustomed to carrying out joint repairs using devices made from titanium – but although it has many of the properties needed for success, titanium is many times stiffer than bone, and can cause deterioration in surrounding tissue.

Researchers at Imperial College London are working with additive manufacturing experts, Renishaw, to design implants made from titanium alloys in a lattice design. They have succeeded in developing a material that matches the natural stiffness and anisotropy of bone that can be used to repair joints or to correct their alignment.

Using the 3D printing process, the team has even succeeded in incorporating a Velcro-style fixing system to the design that means the device can be implanted without the need for screws.

“Bone changes depending on the strain it experiences,” explains Dr Jonathan Jeffers, of Imperial College, who is leading the research. “If you use an implant that’s much stiffer, it reduces the strain on surrounding bone, so it will remodel itself to become less dense and weaker. We need implants that work alongside existing bone but also enable it to retain its strength. “Titanium is already widely used in orthopaedics, so the new properties that we’re introducing will be more easily adopted into the clinic.”

Dr Jeffers is also taking advantage of other materials already in clinical use to take the device into a new area of innovation – resorbable implants.

A magnesium alloy, used in stents by cardiac surgeons to repair arteries, is now being tested as an orthopaedic device using the same design and manufacturing process as the titanium alloy implants. Using IKC proof of concept funding, researchers are developing the material prior to testing in animal models. The aim is to use it to treat younger patients who have a greater ability to regenerate bone.

“The IKC has been able to guide the development of this research, but it’s also been useful to access its network of industry and academic partners,” says Dr Jeffers. “Providing opportunities for potential partners to talk to one another is a valuable part of the innovation process.”

 

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