Lower limb prosthetic sockets could be printed in remote locations or users' homes with a fully digital design-to-manufacturing process developed at Loughborough University.

Loughborough University

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

The method involves taking a cast of the limb that serves as a mould for crafting a socket, but the process requires hospital visits, relies on labour-intensive skills and expertise, and often involves a trial-and-error approach.

The resulting sockets can lead to skin and stability issues if they do not provide a perfect fit. Furthermore, the process has to be repeated frequently as sockets wear down quickly with use; they are replaced every three-to-six months for adults and more regularly for children.

Now, the new method developed by Dr Simin Li, a senior lecturer in Mechanics of Biomaterials in the School of Mechanical, Electrical and Manufacturing Engineering, 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 CAD software, a personalised design profile is generated, which can be imported into a 3D printer for manufacturing. According to Loughborough, the result is a fully customised socket that can be produced in as little as eight hours.

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 print a socket in the user's location, overcoming geographical barriers and transforming the way personalised medical devices are accessed and produced.

In a statement, Dr Li said: “By using a fully digital design-to-manufacturing workflow and additive manufacturing…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 are said to 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.

The team’s technique also allows them to increase design freedoms, making 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.

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.