Adaptable AdhFix patches could replace metal plates on broken bones

Presently, orthopedic surgeons use screwed-in metal plates to hold unstable broken bones together. There may soon be a less problematic, more customizable alternative, though, which incorporates a light-cured composite material.

While traditional metal plates are effective at stabilizing broken bones, they do have at least two drawbacks.

For one thing, it’s difficult to form them into the exact shape needed for each patient, so hospitals typically have to keep plates of various shapes and sizes on hand. Additionally, the patient’s adjacent soft tissue may adhere to them over time, resulting in a loss of mobility or other problems.

With these limitations in mind, scientists at Sweden’s KTH Royal Institute of Technology have developed what’s known as the AdhFix system.

To use it, surgeons start by inserting screws into each section of bone that needs to be stabilized. The heads of the screws are left protruding from the bone, allowing them to serve as anchor points. Next, a temporarily soft and malleable patch is built up across the target area, spanning and encompassing all the screw heads.

That patch is made up of alternating layers of a medically approved polyethylene terephthalate (PET) fiber mesh and a putty-like polymer/hydroxyapatite composite. Once it has been formed into the desired shape and size, it’s exposed to a high-energy LED visible light source, causing it to harden within a matter of seconds. It then stays permanently in place, serving the same purpose as a metal plate – but reportedly without the drawbacks.

A smashed pig's skull, reconstructed using AdhFix patches
A smashed pig’s skull, reconstructed using AdhFix patches

KTH Royal Institute of Technology

In tests conducted on human cadaver hands with fractures to the finger bones, AdhFix patches withstood the forces of repeated finger-flexing exercises. And when the patches were applied to the fractured femurs of live lab rats, they were shown to support bone healing without any adverse effects such as soft tissue adhesion.

The AdhFix technology is now being commercialized by spinoff company Biomedical Bondings. Plans call for it to be available for veterinary use by 2022, and for use on humans by 2024.

A paper on the research, which is being led by Prof. Michael Malkoch, was recently published in the journal Advanced Functional Materials.

Sources: KTH Royal Institute of Technology, Biomedical Bondings

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