Advancements in the Technology of Prosthesis Health
Restoring touch and control to those with prosthetic limbs
Innovations in prosthetic limbs have changed the role of replacement body parts over centuries. Recent developments in prosthetic technology have begun exploring the possibility of restoring the feeling of touch and neuromuscular control.
Director of Health Policy and Advocacy for the American Orthotic and Prosthetic Association (AOPA) Joe McTernan, emphasizes that there is often confusion of vocabulary when discussing the functions, developments and use of prosthesis and orthosis.
Prosthesis is a man-made artificial instrument that replaces a missing body part to restore its biological functions. The term “prosthetic” is an adjective used to describe an instrument that provides these actions.
“Their primary goal is to restore function to the patient to allow them to continue to do what I call their activities of daily living, that might have been restricted or prevented by not having access to that technology. So it's really very, very personal, and it's very, very much tailored to the individual needs of the patients” says McTernan.
There are passive or active prostheses that allow the user to perform functions. Passive devices are strictly used for cosmetic purposes. Active prostheses can be a detachable device or now can be surgically implanted.
Orthotics refers to the correction of affected limbs or bones with supportive and adjustive braces. Orthosis is the devices themselves that are used to realign joints, improve biomechanical functions or to protect limbs from further damage.
Orthotic devices require detailed measurements and considerations specific to the user’s needs.
There are four main types of prosthetic limbs currently available on the market which have varying functions: transradial and transhumeral for arms or transtibial and transfemoral for legs.
Infographic created by Aishah French
Infographic created by Aishah French
McTernan says that a common misconception is that people who use prosthesis or orthosis are disabled or have limited capabilities,
“They're part of what we call the disability community, but if you have a patient who is able to use a prosthesis or orthosis that is truly designed to meet their functional needs, they can do everything that that you or I could do.”
Writer Britt Young disagrees, and says that this isn’t the case when it comes to today’s more technologically advanced prosthesis, “[common misconceptions include] that prosthetic arms are incredibly sophisticated--so sophisticated that they simply eliminate disability at this point. The technology and the lived experience of wearing prosthetics these days isn't like a Marvel movie”.
“A lot of people don't think I can do squats and stuff or like go to the gym but I still do and I run and everything. A lot of people are like, ‘Oh, I didn't know that you were able to do that’” says 17-year old Shaun McLaughlin, who uses a prosthetic leg.
History of prosthesis: ancient Europe to the industrial revolution
Prosthetics are an ancient science, dating back to ancient Greece and Rome in classical literature. Earliest discoveries take us 3000 years back, tracing their evolution from wooden prosthetic toes to movable mechanical limbs.
The revolution of prosthetic production began in the 16th century, when French surgeon Ambroise Paré created prosthesis with supportive harnesses and knee locking mechanisms. These features are still used in modern prosthesis today.
Paré was the royal surgeon for four French kings who used his knowledge of anatomy to improve amputation techniques for higher survival rates and to develop functional prosthetic limbs.
Roughly two centuries later, the industrial revolution brought several notable advancements such as the world's first articulated wooden leg, The Anglesey Leg.
The prosthetic leg was designed for the 1st Marquess of Anglesey, Henry Paget, who lost his leg in battle.
This era also introduces limb-conserving surgeries.
Engineering prosthetic limbs (1914-1918) // Courtesy of Imperial War Museums on Picryl
Engineering prosthetic limbs (1914-1918) // Courtesy of Imperial War Museums on Picryl
Sketch of leg prosthetics developed by J.E. Hanger // Courtesy of Wellcome Collection on Wikimedia Commons
Sketch of leg prosthetics developed by J.E. Hanger // Courtesy of Wellcome Collection on Wikimedia Commons
A doctor creates a plaster cast of an amputee's leg during WWI (1914-1918) // Courtesy of Imperial War Museums on Picryl
A doctor creates a plaster cast of an amputee's leg during WWI (1914-1918) // Courtesy of Imperial War Museums on Picryl
A doctor creates a plaster cast of an amputee's leg during WWI (1914-1918) // Courtesy of Imperial War Museums on Picryl
A doctor creates a plaster cast of an amputee's leg during WWI (1914-1918) // Courtesy of Imperial War Museums on Picryl
History of prosthesis: rebuilding after battle
Prosthetics we see today are comparatively similar to variations developed in response to military conflict.
Confederate States Army veteran J.E. Hanger created a revolutionary prosthesis for himself after losing his leg just under two days of enlisting in the American Civil War. The Hanger Limb prosthesis featured the first articulated knee joint.
Before leaving for service, the 18-year-old was an engineering student. Hanger was the first amputee of the Civil War, and endured a life-saving battlefield amputation. He continued his work to help others with physical challenges by providing prosthetic care through the first world war.
Hanger’s work inspired him to start Hanger Inc., which is still present today providing orthotic and prosthetic (O&P) patient care, services and products.
Even so, innovation in prosthesis technology fell behind as military technology advanced during World War I and World War II.
History of prosthesis: balance and beyond
Technological advances in modern prosthetics begin with Mexican-American inventor Ysidro Martinez, who started a push for more functionality and comfort in prosthetic limbs.
Martinez invented below-knee prosthesis that improved balance and reduced friction allowing for changes in walking pace.
This leads to modern blade prosthesis, also known as running blades which allow the users to sprint. Running blades allowed athletes like Oscar Pistorius, a double leg amputee, to compete in Olympic track events.
“Blade Runner” Pistorius was the first amputee to compete in track events at the olympics against non-amputees.
This wave of technological prosthetic advancement achieves higher functionality in the restorative journey of prosthetic and orthotic rehabilitation.
The running blade helped McLaughlin stay active and to pursue his interests “I had a lot of fun with it. Because I was able to keep up with my friends or in like elementary school, at recess and everything”.
Born without his right leg below the knee, McLaughlin has been using prosthetic legs before he could crawl. Although he has always had prosthetic legs, changing styles over the years were inevitable to accommodate for his physical growth and interests.
Like the blade foot, which can only be used for running. Using this prosthesis for walking can cause hip problems in the future as it elevates the side it’s attached to, creating an uneven gait.
Oscar Pistorius in the first round of the 400m in 2012 London Olympics // Courtesy of Jim Thurston
Oscar Pistorius in the first round of the 400m in 2012 London Olympics // Courtesy of Jim Thurston
Oscar Pistorius and Nigel Levine in the 400 semi finals // Courtesy of Darren Wilkinson
Oscar Pistorius and Nigel Levine in the 400 semi finals // Courtesy of Darren Wilkinson
Oscar Pistorius competing in the 2012 London Olympics // Courtesy of Will Clayton
Oscar Pistorius competing in the 2012 London Olympics // Courtesy of Will Clayton
Oscar Pistorius wins the 400m // Courtesy of David Jones
Oscar Pistorius wins the 400m // Courtesy of David Jones
Modern developments in prosthesis
“Right now I have a hybrid foot. It’s like a mix between a running blade and walking foot. But when I was younger, they didn't have one for kids. And so I had to either use just a walking foot or running blade that I had made for me. So it's nice now that I can use a natural hybrid foot” says McLaughlin.
Advancements in technology have allowed for increasingly functional prosthetic limbs. Although users may still need to attend prosthetic physical therapy to exercise its use, these new developments have revolutionized the manufacturing, functionality and abilities of prosthesis.
3D printing allows for durability and customized collaborative design of prosthetics tailored specifically to the users themselves.
Traditional orthotic devices are standardized solutions that may not work for different users. However with new advancements, these orthoses can be tailored to the users needs to promote comfort and wearability.
McLaughlin switched from a pin system prosthesis to a suspension sleeve as he grew because the former irritated his leg. He continues to use the suspension sleeve with a one-way valve that helps keep the prosthetic on comfortably.
Passive prosthesis
Silicone prosthesis are custom-made cosmetic prostheses that are made to seamlessly match the user’s body. An artist will paint clear silicone gloves or sleeves with matching skin tones, body hair, freckles and any tattoos the user may want.
If the user would like a prosthetic on one arm and has another hand that is able to help position it, there are also multi-positional joint prostheses. These jointed prosthetic devices can be positioned at the shoulder, elbow, wrist or fingers to grasp objects.
Partial hand or finger amputees also have several options that can be positioned in the same way.
Active prosthesis
Body-powered prosthesis allow the movement of the user’s remaining muscles (upper arm, shoulder, chest) to open and close the prosthetic hook or hand. These devices have custom fit sockets.
Myoelectric upper limb prosthesis reads electric signals generated by the contraction of muscles. These contractions are read by electrodes in the prosthesis’ socket, and translate into movements of the prosthetic elbow, wrist, hand and/or fingers.
These prostheses allow for more control over grip strength and hand movements.
The future of prosthetic limbs
Even the most advanced motorized prosthetic limbs used today require deliberate physical therapy. This creates a learning curve for users who have to learn which and how muscles should be flexed as programmed by their prosthetists.
Prosthetic manufacturers and innovators have begun to explore possibilities for users to be less burdened by their prosthetic limbs. Researchers and developers are working towards restoring touch and mind control to those with prostheses.
Startup prosthetics company Atom Limbs combines artificial limb design with artificial intelligence (AI) and modern robotics to improve bionic arms. Their goal is to improve prosthetics beyond a “task-based tool industry” while lowering the financial burden of purchasing prosthetics as written on their website.
Atom Limbs is currently working on their first prosthetic arm with the Atom Touch which is set to be released in 2023. The company claims that this arm will provide its users with a full range of motion controlled by the user’s brain signals and even a basic sense of touch.
Even so, some speculate that these advancements are contributing to a positive future in prosthetic technology.
Critics and conflicts of modern prosthesis
There is currently a gap in accessibility to the more technologically advanced upper extremity prosthesis due to lack of policy,
“A lot of insurance companies just simply don't have policy, at all, that govern the coverage of upper extremity prostheses. So, what often happens is when it comes to a need for an upper extremity prosthesis, patients are often limited to just very basic devices,” says McTernan
“But because the technology has always been seen as really only for the elite users, the really high end users. There's a lot of restrictions in place that don't even allow for lower functional users to have access to that technology” he continues.
“All of these things are just more expensive, more difficult to repair, and more difficult to access,” Young says in reaction to new technological advancements in prosthesis, “The thing is, prostheses are still commodities. They are businesses. And business models today want more subscribers, they don't want to offer repairs, and they want people to be dependent on buying more.”
She says that prosthesis is embedded in the assumption that the body is broken, and need to be altered to meet needs that the world cannot accommodate for.
Young does not believe that these new advancements are helping those who are looking to get a prosthetic limb, “The best prosthesis is simple, repairable in your own home, cheap, easy to use, and customizable. The incentives for making something like this are very limited, especially under a for-profit medical regime”.
Infographic created by Aishah French. Data used to create this graphic is from Current rates of prosthetic usage in upper-limb amputees - have innovations had an impact on device acceptance?
Infographic created by Aishah French. Data used to create this graphic is from Current rates of prosthetic usage in upper-limb amputees - have innovations had an impact on device acceptance?
Britt H. Young's author photo // Courtesy of Gabriela Hasbun
Britt H. Young's author photo // Courtesy of Gabriela Hasbun
McLaughlin says that although some of the technological advancements in prosthesis are attractive, he doesn’t really need them for his interests, “I do wrestling. And for that I don't need my leg. Which is a big thing. If I played football or something, I definitely think there would be more of a lack of mobility because I can't push off that side as much”.
Growing up, he tried sled hockey, soccer and baseball...but none of them stuck like wrestling, “And I really liked it because I didn't need to use my leg. Even if my leg wasn't fitting or something was wrong, I could still wrestle because I could just wrestle without it”.
Built with Shorthand