Dr Simin Li, a Senior Lecturer in Mechanics of Biomaterials, and a team of researchers in the School of Mechanical, Electrical and Manufacturing Engineering have pioneered a fully digital design-to-manufacturing process that has the potential to revolutionise lower limb socket production by allowing printing outside of hospital settings.

Traditionally, the creation of a lower limb socket has been a time-consuming process, taking around three-to-six weeks.

The method involves taking a cast of the limb, which serves as a mould for crafting a socket. The process necessitates visits to hospitals, relies heavily on labour-intensive skills and expertise, and often involves a trial-and-error approach.

The resulting sockets, according to Dr Li, are more akin to “works of art than medical devices” and can lead to skin and stability issues if they do not provide a perfect fit.

This process also has to be repeated frequently as sockets wear down quickly with use. They are replaced every three-to-six months for adults and even more regularly for children.

Dr Li and team's revolutionary method utilises a variety of technologies and unique coding to create a socket through a fully digital process.

By capturing a 3D scan of the user's limb with a digital scanner and employing computer-aided design (CAD) software, a personalised design profile is generated, which can be imported into a 3D printer for manufacturing.

Pictured, from left to right, Dr Simin Li with Doctoral Researcher Theodoros Marinopoulos, and Dr Nathaniel Kaill, who are part of the research team behind the innovative process. 

The result is a fully customised socket that can be produced in as little as eight hours, making the process significantly faster than current methods.

What is unique about Dr Li's method is its potential to enable 3D printing of sockets in remote locations and even in users' homes.

The digital scanning and 3D printing facilities can be deployed to different areas, including under-served regions and developing countries with limited access to healthcare.

Lower limb prosthetic users could scan their limb, send the scan to a healthcare expert who can process the design remotely, and receive a customised design file in return.

This file can then be used to conveniently print a socket in the user's location, overcoming geographical barriers and transforming the way personalised medical devices are accessed and produced.

Dr Li said: “By using a fully digital design-to-manufacturing workflow and additive manufacturing – or ‘3D printing’ as it’s commonly known - our entire process for creating a socket is quantitative and iterative, therefore, highly customisable, repeatable, and efficient.

“By using the innovative digital solution, healthcare professions can focus more of their valuable time with users and therefore, increase the accessibility for all and on-demand.

“The ultimate goal for this project is to make the design and manufacturing process easier and more accessible for both the healthcare professions and user so that one day the prosthetic socket can be manufactured in local community areas, hospitals and even in users’ homes on demand.”

Dr Li and team have optimised their 3D printed socket designs through extensive testing in their in-house developed facilities, which involves subjecting printed prototypes to loads ranging from 6,000 to 16,000 Newtons, equivalent to seven-to-20 times of body weight, depending on the user.

The team’s technique also allows them to increase design freedoms, meaning they can make regions on the socket harder or softer depending on the users’ needs, which Dr Li hopes will improve comfort and further facilitate users’ participation in play, physical activity, and sports. 

Their next step is to collaborate with academic and industrial partners to transform their 3D printed socket prototypes into real-world products and explore the application of their process in diverse settings.

Dr Li said: “I hope to see this research one day benefiting lower limb prosthetic users worldwide and kick-start broader discussions about using 3D printing for medical devices and beyond.

“Currently, the entry barriers for accessing healthcare facilities, medical professionals, and 3D printing techniques in remote locations is too high.

“We believe our research will not only breakdown these barriers, but act as a catalyst for other exciting innovations that utilise 3D printing.”

Paratriathlete Finley Jakes, a lower limb prosthetic user and a recent Loughborough University graduate, visited Dr Li and team to hear more about their research.

Finley – who is a member of the British Triathlon Paralympic World Class Programme and has represented and medalled for Great Britain at events around the world - told the researchers it usually takes around a month for him to receive a socket and that he has experienced skin issues as the result of wearing poorly fitted sockets.

He said of the project: “I think this research could benefit so many people, especially children growing up that need sockets readily available. It has huge potential.”

More on Dr Li and team’s research, which is funded by an EPSRC Redistributed Manufacturing in Deployed Medical Care grant, can be found on the dedicated webpage.

Potential academic and industrial collaborators that are interested in bringing the product closer to reality, and prosthetic users that are interested in participating in research are asked to contact Dr Li at: S.Li@lboro.ac.uk.