Jeremy J. Mao, DDS, Ph.D.

A new type of personalised implant could be used to replace the meniscus – the knee’s protective lining – in order to help prevent arthritis.

Columbia University Medical Center have devised a way of using a 3D-printed implant or scaffold infused with human growth factors to prompt the body to regenerate this lining on its own, offering a viable alternative to meniscal transplant surgery, which is often unsuccessful.

As described in the medical journal Science Translational Medicine, this approach transforms magnetic resonance imaging scans of the intact meniscus in the undamaged knee into a 3D image, which can then be printed out in exact detail in about 30 minutes.

Made of polycaprolactone, a biodegradable polymer that is also used to make surgical sutures, the scaffold is infused with two recombinant human proteins that can attract existing stem cells from the body and induce them to form meniscal tissue.

This process has been successfully tested in sheep, the knees of which closely resembles those of humans. After three months, treated animals were walking normally again.

Study leader Dr Jeremy Mao, professor of dentistry in orthopaedic surgery at Columbia University Medical Center, said: "This is a departure from classic tissue engineering, in which stems cells are harvested from the body, manipulated in the laboratory and then returned to the patient – an approach that has met with limited success. In contrast, we’re jumpstarting the process within the body, using factors that promote endogenous stem cells for tissue regeneration."