Czech researchers develop 3D-printed, tailor-made artificial joints to last a lifetime

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Researchers from the Brno University of Technology have developed tailor-made joint replacements designed to last a lifetime. What's more, unlike current essentially one-size-fits all implants, the new 3D-printed prosthetic ones do not require healthy bone – or much tissue – to be removed.

The new joint implants developed in Brno are printed based on extensive CT images of individual patients. As such, they replace only cartilage and necrotic bone tissue, and so recipients are unlikely to suffer long-term discomfort or ever need a second replacement surgery.

The innovation didn’t come overnight or in a single ‘eureka’ moment: Miroslav Píška of the Institute of Engineering Technology has been working on the design and technology with his team for more than twenty years.

Photo: archive of University of Technology Brno

“Existing technologies are based on the idea that we make certain types and dimensions of knee or joint replacements in advance and only then the surgeon determines the size of your joint, directly in the operating room. To do that, other aides must be inserted and, unfortunately, there is often a loss of healthy tissue, which does not grow back.”

Loss of healthy tissue can lead to considerable problems later on. And if a prosthetic implant is not a perfect fit, the patient’s gait will be off kilter, which can lead to chronic back pain. With tailor-made joints, such side effects are unlikely to arise, Miroslav Píška says.

“In this case, we get a perfect joint that is functional with no cut bone losing much of its load-bearing capacity. The material is dense and has unique properties. On the one hand, it is shiny like a mirror; on the other hand, it is coarse, porous, it can penetrate bone tissue, which means that it is perfectly fixed to the bone. The implant contains a parabolic reinforcing rib. It is likely to last far longer than existing implants.”

It was the search for suitable material and technology that took the Czech team years of work. Stress tests show the samples last up to 13 million cycles without failing, confirmation of the exceptional high-quality material.

Photo: archive of University of Technology Brno

The artificial joints are formed by melting a metal powder compound in a vacuum using an electron beam, from which a titanium alloy is formed thanks to 3D printing. The new implants are thus also significantly lighter than current castings, forgings or workpieces, without sacrificing strength or durability.

“We get the material from Sweden, where it has been used for other biological implants. We don't make it because you really need high-quality certification and to ensure it is chemically pure. The material is based on two-phase titanium alloys, in balls of about 50 micrometres in diameter. Another huge advantage is the processing technology. We do it in a protective atmosphere, a vacuum, not with laser beams. The resulting quality is then admirable.”

Píška and his team have applied for a patent on their joint replacement design and technology, which he says also greatly shortens the rehabilitation period and may never need to be replaced – an especially attractive feature for athletes, including dancers.