The prosthetics industry has never been busier. Every other week seems to bring a new study into arms that can sense touch, or a university student revealing a new method for cheaper manufacturing. It can be easy to forget how far prosthetic technology has come. This article aims to be a useful document to show just how far prosthetics have advanced, and how much knowledge about prosthetics we have. Let's get started!
Ancient prosthetics
The history of prosthetics goes back further than many people think. The earliest practical prosthetic discovered is a big toe from ancient Egypt, which allowed its wearer to walk barefoot and wear sandals. Using carbon dating, scientists estimate the toe to be from around 900-700 BCE - that's almost three thousand years old!
We also have examples of prosthetic arms and legs from throughout the middle ages and late mediaeval periods. These were mostly made for knights, allowing them to continue holding shields or swords, and therefore weren't very helpful in everyday life. And of course, there was little in the way of physical therapy or treatment in those days, so learning to use their prosthetics was a solo endeavour.
Early-modern prosthetic devices
Through steady advances in the surgical process involved with amputation, standardised devices became more commonplace. Most of the prosthetics of this time remained rather simple, keeping them cheap and available. This was the era of wooden peg legs, sometimes with knee adjustment, and early use of springs and other tendon controls.
New stages of improvement came after WW2, when the National Academy of Sciences started advocating for research and development into prosthetics. This provided scientists like James Foort with government funding, giving experts much more support than before.
James Foort helped develop early-modern prosthetic feet. One of the most important developments he made was the use of plastic, which made the prosthetics much more durable. This was inspired by his MSc in chemical engineering and the complaints of fishermen from childhood jobs. Prosthetics were also made more modular, rather than being sculpted individually, which made them easier to manufacture cheaply.
Modern prosthetic devices
People using prosthetics in the modern day have a choice to make when looking for a new prosthetic. Each design is slightly different, working better for some people than others. Of course, which device depends on the healthcare and functional needs of each patient.
Myoelectric prosthetics are controlled by electrode sensors, which measure electrical signals generated in the residual limb. These signals then prompt the arm to move. Some designs take this a step further and implant the electrode sensors next to nerves in the body, but most rely on surface contact in the socket. Most myoelectric devices come with a hand, as opposed to a hook or other terminal device, which can make several grip patterns. Some more modern designs use AI, meaning that by using the arm you are training the computer inside, making the experience of picking an object up much smoother.
It can take some time and practice to develop the skills to control a myoelectric arm, which is why some people continue to use a body-powered option. These prosthetics are characterised by having no battery - they are powered by cables attached to a harness, and movement is controlled by the residual limb or (sometimes) the shoulder on the opposite arm. Professionals in rugged environments, such as those in workshops, prefer a body powered prosthetic as they have a finer degree of control, and don't have to worry about charge or incorrect inputs.
Some people with congenital limb differences don't need a full prosthetic device. Orthotics are braces that support the skeletal system externally, which can reduce pain and make people more mobile. They can also be used as a rehabilitation device for people who have suffered injuries.
Whatever requirements you have from a modern prosthetic, there's certain to be a design out there that's the right fit for you. If you'd like more information about how modern prosthetic devices work, you can check out our dedicated FAQ page of our website here.
A new frontier of prosthetic technology
Major leaps in prosthetic technology have been made by DARPA's 'Revolutionizing Prosthetics' project. DARPA is a military research institute, who have previously pioneered technologies like night vision and GPS. The focus on prosthetics came from the need to provide health care for veterans. They found that former soldiers, after being amputated due to injuries in Afghanistan or Iraq, were still using body powered hooks, nearly unchanged from the post-WW2 designs.
As a result, the Revolutionizing Prosthetics project started in 2005, and its goal was to revolutionise prosthetic arms in particular. While there was lots of progress in the development of prosthetic legs, arms are considerably trickier to get right. There are many more components involved, and we rely on our hands for much more complicated and precise tasks.
Clinical trials of the LUKE and DEKA arms were conducted up until 2014, when it was FDA approved and Mobius Bionics began manufacturing them. With multiple control options and several points of articulation, these are some of the most advanced robotic arms on the market today.
Prosthetic accessibility
Prosthetics have been advancing outside of the realms of sci-fi and theory too. Useful new technologies like 3D printing have allowed for much more affordable and better-fitting prosthetics. This has made prosthetics more accessible to those who need them than ever before.
ExpHand is one such project, aiming to deliver affordable devices to children with 3D printing technology. Many families can't afford to replace a costly myoelectric every few years as their children grow, which is where ExpHand's methodology comes in. By designing an arm with an adjustable length, we have made a product that can be worn for years by a child as they grow. For more information you can read about us here.
The NHS in the UK has also been working to provide more prosthetics. After being offered to veterans and service people, projects like the hero arm by Open Bionics are becoming increasingly available to the general public. Patients have to go through NHS consultation to be offered these though, which means a long waiting list and the potential for a myoelectric prosthetic to be deemed not the right fit.
The future of prosthetic devices
So, the future of prosthetics looks pretty bright! The last 20 years have seen huge leaps forwards in the science and affordability available to designers and manufacturers - it's truly never been a better time to be in the market for a prosthetic!
There is a need for improved education around prosthetics, for those with and without limb difference. News stories tend to focus on the latest and greatest in prosthetic technology, as opposed to what is available to people from their local hospital or specialised clinic.
While research pushing the boundaries is important, so is technology that is functional and practical to users from all walks of life. Advocacy and education is still important to show how far these designs are from being realistically available and affordable products, though we're sure it's just a matter of time until that's a reality.
We hope you've enjoyed learning about the history of prosthetics. There is a lot more information out on the internet that we couldn't go into here, but we encourage you to do further research if you're interested! Or, if you'd like to learn more about ExpHand, click here to get in touch with us!
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