Universal-fit, Adjustable, Low Cost Prosthetic for Children

An easy-to-assemble, low-cost 3D-printed prosthetic kit fulfilling the unmet needs of child amputees in developing countries.

We are producing a low-cost 3D-printed universal fit trans-radial prosthetic that can address the pressing need, particularly with children, for an accessible and adjustable prosthetic that can drastically improve their lives. Our focus is on children in developing countries who have lost limbs due to injury, illness, or birth defects in communities with little to no access to quality healthcare and limited medical technology. To date, only a fraction of them has access to a prosthetic, given its high cost, inflexibility, and requirement for a healthcare professional. In addition, for them, as they grow, even if they had one to start, they would need to replace them frequently since the fit changes over time. 

According to research published in Prosthetics and Orthotics International in December 2020, as of 2017, 57.7 million people are living with limb amputation due to traumatic causes worldwide. 30 to 40 million are in developing countries, with approximately 55 percent being children. Many cannot afford a prosthetic device, so, as a result, are denied opportunities to succeed. One of the main reasons for the need for prosthetics in developing countries is the high prevalence of injuries and illnesses that result in limb loss. In many of these countries, inadequate healthcare infrastructure, lack of access to medical services, and lack of education about proper healthcare can all contribute to the high rates of injuries and illnesses. 

Of the 30-40 million amputees in the developing world, only ~5% have access to prosthetic devices (LIMBS International). Various barriers exist today with the current prosthetic offerings: (1) high cost of production; (2) high cost of materials, and (3) very limited access to healthcare professionals to fit the current prosthetics. For children, these issues are compounded because as they grow, the prosthetics are not adjustable, so a new one is required. 

To address this problem, a solution is required that is low cost, high quality, and very easy to use. The child must be given an easy-to-assemble kit that can immediately be put on and be usable. It should not require a healthcare professional to fit it. It also should not need to be replaced when the child grows. Our innovative technology solution overcomes those issues. 

Our product is a low-cost (<$30), easy-to-assemble kit that can be used immediately without a healthcare professional and adjusted easily over time. It leverages 3D printing and the new capabilities that technology provides for efficient, low-cost fabrication, but also is designed to be a simple kit of parts that is easy to assemble. It improves on the current design of the socket for trans-radial prosthetic limbs to produce an adjustable universal fit for both children and adults. The socket uses a BOA tensioning dial, flexible struts, and twist-and-lock mechanisms to accommodate various residual limb sizes, which allows for a continuous fit for children throughout their growing ages while also allowing adjustment for small volume changes in adults. Additionally, by employing a 3D printable design, the prosthetic could be manufactured within a developing country, increasing accessibility and reducing cost. 

Our current research team has been working for almost 1 ½  years on the product. The team is led by Arav Bhargava and includes two key advisors: Dr. Isabelle Cohen, faculty leader at The Potomac School in Mclean, and Dr. Siddhartha Sikdar, Professor, Department of Bioengineering and Director of the Center for Adaptive Systems of Brain-Body Interactions at George Mason University. We have also benefited from the advice of experts at the MIT Media Lab, Brigham & Women’s Hospital, and Medical Center Orthotics and Prosthetics.

We are currently finalizing the prototype and are targeting the production of our first units by the end of 2023. We believe we have a viable business model since the cost of R&D and production is low, and therefore, the funding requirements are manageable. The operational efficiency of the social enterprise is expected to be high since 3D printers are becoming more readily available at lower costs, and distribution can be done through existing organizations. 

As mentioned above, the need is very large. According to the Institute of Health Metrics, as of 2017, 57.7 million people are living with limb amputation due to traumatic causes worldwide, most of which are in developing countries and many of whom are children who can not afford a solution. Of the 30-40 million amputees in the developing world, only ~5% have access to prosthetic devices (LIMBS International). 

We also expect the demand to remain sizable. One of the main reasons for the need for prosthetics in developing countries is the high prevalence of injuries and illnesses that result in limb loss. In many of these countries, inadequate healthcare infrastructure, lack of access to medical services, and lack of education about proper healthcare can all contribute to the high rates of injuries and illnesses. For example, in some developing countries, road traffic accidents are a leading cause of limb loss, and the lack of safety regulations and infrastructure can make these accidents more likely to occur. In addition, certain diseases, such as diabetes and some forms of cancer, can also result in limb loss, and the lack of access to quality healthcare can make it difficult to diagnose and treat these conditions.
At the individual level, we expect we will change each recipient’s life. This adjustable and accessible prosthetic will allow these children without limbs to regain their mobility and independence. Losing a limb can be a traumatic experience, both physically and emotionally, and it can significantly impact an individual's ability to work and support themselves and their families. Individuals with limb loss may be unable to find work or may be limited to low-paying, physically demanding jobs that may further exacerbate their physical limitations. This can lead to poverty and social isolation, which can have long-term negative impacts on both the individual and their community.
By providing individuals with artificial limbs, they can once again engage in activities that may have been previously impossible, such as walking, running, and working. This can improve their quality of life, allowing them to support themselves and their families, and can also help to reduce the impact of limb loss on their communities.

Right now, it is incredibly challenging to obtain, properly fit and maintain prosthetics that can help them. To address this need, our low-cost, easy-to-use, adjustable prosthetic helps solve the issues of limited healthcare access and high-cost, inflexible options.  

I am a 17-year-old that has been part of a 3-year research program at The Potomac School for a select set of students. That program has provided me with the opportunity to spend most days for the last few years conducting research and using their 3D printing capability to develop the product. I have benefited significantly from the guidance of Dr. Isabelle Cohen, who leads the program. 

In addition, we have been able to work with Dr. Siddhartha Sikdar, Dr. Siddhartha Sikdar is a professor and the Director of the Center for Adaptive Systems of Brain-Body Interactions at George Mason University. He has great experience in the field and a strong interest in figuring out a low-cost product for developing countries.  

Other advisors, such as Will Garcia at Medical Center Orthotics and Prosthetics and Shriya Srinivasan at MIT Media Lab, have been helpful with the technology development, and we have used advisors to help me develop the business model. 

We believe existing nonprofit organizations in the area, such as LIMBS International, Exceed Worldwide, International Committee of Red Cross, Legs4Africa, and Cooperative Orthotic and Prosthetic Organization, will be very helpful in our go-to-market strategy, but we have to reach out to them. 

We have spent several years meeting with amputees, prostheticists, surgeons, and researchers to understand the current devices available and technology advancements. 

To understand the patients, I visited Walter Reed Veterans Hospital and met with numerous patients who shared their stories of how they lost their limbs; the impact on them emotionally, mentally, and physically; the prosthetic they are using, and the adjustments they are making. I also met patients at the Medical Center of Orthotics and Prosthetics.  In each case, I was able to hear their story and understand the sophisticated technologies they have available in the United States. 

To further understand their mindset and to help educate others, I started a podcast called The Prosthetic Experience, where I am interviewing patients, prostheticists, surgeons, and researchers on their experiences in order to educate and inspire. Link:

https://open.spotify.com/show/0lz2kKQ39NaToBwHfEiVWQ 

On the other side, I spent time trying to understand the latest technology and what researchers were focused on. After watching Augmented, a PBS documentary about the first below-the-knee “Ewing amputation,” I reached out to Dr. Matt Carty, who is the surgeon at Brigham featured, and Dr. Shriya Srinivisan at MIT Media Lab, who is working on the research. 

The technology is remarkable, but it was clear they are targeting high-end, very expensive cutting-edge technology and are not focused on the low-cost, easy-to-use options. 

The combination of those visits and conversations, together with my own personal experience seeing impoverished children on my visit to India and Mexico, helped me understand this unfulfilled need and led me to embark on this 1 ½ years ago. 

We are creating a low-cost 3D printed universal fit trans-radial prosthetic that can address the pressing unmet need, particularly with children, for an accessible and adjustable prosthetic that can drastically improve their lives. Our focus is on children in developing countries who have lost limbs due to injury, illness, or birth defects but are unable to access prosthetics. Of the 30-40 million amputees in the developing world, only ~5% have access to prosthetic devices (LIMBS International) because the current prosthetic options are (1) very expensive — $5,000 - 50,000; (2) inflexible; (3) easy to damage and (4) require doctors to fit the device and help manage them. For many children, even if they were lucky enough to access a prosthetic at some point, they are unable to continue to replace them as they grow due to the cots. 

The current offerings of prosthetics in developing countries are not viable. Most commonly used are passive, non-functional prosthetics that serve as cosmetics. Few communities have access to the more technical prosthetics that allow hand movement and 3D-printed prosthetics. Still, the cost of these prosthetics, specifically developed for low-cost applications, is much too high.

Considering this, our enterprise will produce easy-to-assemble, low-cost (<$30 to produce), adjustable kits that can be delivered to the amputee and used immediately. Our innovative technology improves the socket design for trans-radial prosthetic limbs to produce a universal fit socket for both children and adults that ensures low-cost, high functionality, no requirement of experienced doctors, and long-lasting durability. The socket accommodates various residual limb sizes, which allows a continuous fit for children throughout their growing ages while also allowing adjustment for small volume changes in adults. Additionally, by employing a 3D printable design, the prosthetic could be manufactured within a developing country, increasing accessibility and reducing cost. 

The device’s ability to adjust has a big impact. With current technologies, in order to ensure that a child's prosthetics can keep up with their changing body, the socket of the prosthetic (the part that fits over the residual limb) will need to be replaced every six months as the child grows. This can be a frequent and costly process, especially if the child is growing quickly. In addition to the need to accommodate a child's changing body, children are also more active and may put more wear and tear on their prosthetics than adults. This can lead to a higher risk of breakage and damage, which can be expensive to repair. By providing children with low-cost adjustable prosthetics, families can save money on these repairs and ensure that their child has access to functional prosthetics at all times.

A low-cost, mass-market, easy-to-use product that could be produced locally or shipped cheaply and can be distributed through existing networks will be embraced by these low-income amputees who are struggling. Our product will be a catalyst to change the lives of millions of children in developing countries. 

We would like to provide our prosthetic kit to 50 patients by the end of 2023 and then target 1,000 patients in 2024. To achieve this impact goal, we are currently finalizing and starting to gather the information needed to test it on patients. We will, in parallel, raise funding, set up 3D printing capacity, and partner with distribution partners to set up a wider distribution in 2024. 

At the individual level, we expect we will change each recipient’s life. This adjustable and accessible prosthetic will allow these children without limbs to regain their abilities and independence. Losing a limb can be a traumatic experience, both physically and emotionally, and it can significantly impact an individual's ability to work and support themselves and their families. Individuals with limb loss may be unable to find work or may be limited to low-paying, physically demanding jobs that may further exacerbate their physical limitations. This can lead to poverty and social isolation, which can have long-term negative impacts on both the individual and their community.

By providing individuals with artificial limbs, they can once again engage in activities that may have been previously difficult, such as managing daily activities and working. This can improve their quality of life, allowing them to support themselves and their families, and can also help to reduce the impact of limb loss on their communities.

Right now, it is incredibly challenging to obtain, properly fit and maintain prosthetics that can help them. To address this need, our low-cost, easy-to-use, adjustable prosthetic helps solve the issues of limited healthcare access and high-cost, inflexible options.  

The project aims to improve the design of the socket for trans-radial prosthetic limbs to produce an adjustable universal fit prosthesis for both children and adults. The socket accommodates various residual limb sizes, which allows a continuous fit for children throughout their growing ages while also allowing adjustment for small volume changes in adults. The design also provides a length extension for the arm as the child grows. Additionally, by employing a 3D printable design, the prosthetic could be manufactured within a developing country, increasing accessibility and reducing cost. To create such a prosthetic with optimal technology, several aspects must be considered:

• How can uniform compression be applied to the residual limb while maintaining adjustability and accommodating various residual limb sizes?

• How can 3D printing substrates, such as TPU, PETG, and nylon, provide a flexible yet durable quality for the flexible socket?

• What mechanisms prove most effective for accommodating different limb circumferences and lengths?

We are testing a trans-radial socket that uses flexible struts – encircled with a wire tensioning BOA © dial – that takes the shape and applies uniform compression to the residual limb. Alpha classicⓇ liner with soft prosthetic straps layered above the liner will be modified with attachment points for the flexible struts of the socket. The prosthetic hand will be functional through body power with a cable running from the hand to a strap on the user’s opposite shoulder. 

Using BOA© dial tensioned struts, telescoping limb length adjustment with locking mechanisms, and soft prosthetic straps around the residual limb, are for the purpose of accommodating various residual limb sizes (10-18 cm length and 17-27 cm circumference), uniformly compressing the residual limb, and supporting up to 8 kg of weight vertically and horizontally without slip or breakage. The low-cost fabrication technique of 3D printing should allow the prosthetic design to be kept under 40 dollars and be fabricated around the world with pre-made kits. 

We are using Fusion 360 as computer-aided design software to design the 3D printable blueprint of the struts-based socket and an Ultimaker 3 to print iterations of the socket. Testing the prosthetic prototype design is experimentally based: prototypes are printed in PLA at a 0.5x scale, and dimensions are analyzed. From here, we have made major steps toward a valuable prototype. Once this prototype is considered fully functional, the prototype will be printed at full scale in PETG (struts will be layered with TPU for flexibility), and a BOA adjustable dial with a wire through each strut will be added. Testing will consist of several mechanical and functional tests. The prosthetic will be donned to several patients of various residual limb sizes, and weighted loads will be applied to the wrist unit horizontally and vertically to determine the socket's weight-bearing capabilities. For functional testing, accuracy and functionality tests such as the modified box and blocks test will be performed to gauge the performance of the body-powered socket. Lastly, the comfort levels will be rated on a Likert scale throughout the functional and mechanical testing process. 

We would like to provide our prosthetic kit to 50 patients by the end of 2023 and then target 1,000 patients in 2024. To achieve this impact goal, we are currently finalizing and starting to gather the information needed to test it on patients. We will, in parallel, raise funding, set up 3D printing capacity, and partner with distribution partners to set up a wider distribution in 2024. 

At the individual level, we expect we will change each recipient’s life. This adjustable and accessible prosthetic will allow these children without limbs to regain their abilities and independence. Losing a limb can be a traumatic experience, both physically and emotionally, and it can significantly impact an individual's ability to work and support themselves and their families. Individuals with limb loss may be unable to find work or may be limited to low-paying, physically demanding jobs that may further exacerbate their physical limitations. This can lead to poverty and social isolation, which can have long-term negative impacts on both the individual and their community.

By providing individuals with artificial limbs, they can once again engage in activities that may have been previously difficult, such as managing daily activities and working. This can improve their quality of life, allowing them to support themselves and their families, and can also help to reduce the impact of limb loss on their communities.

Right now, it is incredibly challenging to obtain, properly fit and maintain prosthetics that can help them. To address this need, our low-cost, easy-to-use, adjustable prosthetic helps solve the issues of limited healthcare access and high-cost, inflexible options.  

The key challenge is proving our solution as a functional prosthetic. We believe we will overcome those challenges through the process of patient testing and optimizing, which will enable us to produce units with 3D printing cost-effectively and at volume. We also believe we can distribute through local nonprofit healthcare organizations. 

Our team is working through the technical considerations to maximize printability and usability and minimize cost. We are currently testing the socket and controls. 

The key technical aspects that are still being finalized and tested include

• Infill value, which will provide sufficient strength and support for the prosthetic without adding unnecessary weight or cost. Higher infill percentages may be necessary for certain applications, such as prosthetics that will be subjected to high stresses or heavy use, but also may add time and cost to print.

• Material/ filament, with the most likely being PETG (Polyethylene Terephthalate Glycol-Modified) and TPU (Thermoplastic Polyurethane), but possibilities including ABS (Acrylonitrile Butadiene Styrene), PLA (Polylactic Acid), or Nylon

• The team has finalized the wall thickness of 1.6-2.0 mm which is ideal for most 3D-printed prosthetics and allows the print to maintain durability while also printing efficiently. 

• The solution must be tested for Grip strength, range of motion, endurance, drop, fatigue, and weight bearing. 

Ultimately we will launch a pilot with test subjects and will use statistical analysis to make necessary improvements. 

Finally, we will build manufacturing capacity and distribution partnerships for future volume.

The Potomac School and its Science Engineering Research program, a select program for 8-11 students per class that spend three years working on an innovative research solution. The program is run by Dr. Isabelle Cohen, Ms. Laura Petro, and Mr. Doug Cobb.

Dr. Siddhartha Sikdar, Professor, Department of Bioengineering and Director of the Center for Adaptive Systems of Brain-Body Interactions at George Mason University.

I also have been able to work with Will Garcia at Medical Center Orthotics and Prosthetics, Shriya Srinivasan at MIT Media Lab, Louise Hassinger at Walter Reed Hospital, and Dr. Matt Carty at Brigham & Women’s Hospital. 

Our goal is to reach out to potential distribution partners such as LIMBS International, Exceed Worldwide, the International Committee of Red Cross, Legs4Africa, Cooperative Orthotic, the Victoria Hand Project, the World Health Organization, and the Prosthetic Organization by June 2023.

Our product’s value proposition: a low-cost, 3D printed universal fit prosthetic kit that can be easily assembled by anyone and does not need a healthcare professional. The product will cost <$30 to produce, and with a local 3D printer and commonly found filaments, can be produced in the local country.

Key resources, Activities & Partners: 

• R&D:  

  • Dr. Isabelle Cohen and the Science and Engineering program at The Potomac School in McLean, Virginia

  • Dr. Siddhartha Sikdar, Professor, Department of Bioengineering and Director of the Center for Adaptive Systems of Brain-Body Interactions at George Mason University. I also have been able to work with Will Garcia at Medical Center Orthotics and Prosthetics and Shriya Srinivasan at MIT Media Lab 

• Manufacturing: Currently utilizing 3D printers at The Potomac School and low-cost materials (multiple sources given the commonality of materials)

• Distribution: Leverage existing prosthetic-focused organizations in developing countries, including LIMBS International, Exceed Worldwide, International Committee of Red Cross, Legs4Africa, and Cooperative Orthotic and Prosthetic Organization, among others.

• Donor network & brand

Cost Structure: low-cost R&D, manufacturing, and distribution. With product at <$30, can have high operational efficiency.

Go to Market: Leverage the distribution network.

Financial Model: Use donor funding and consider the ancillary revenue path by selling some products domestically to children for low prices but enough to generate some revenue that can subsidize international efforts.

Our social enterprise intends to provide low-cost prosthetics through distribution partners to low-income clients. Similar to other fee-for-service type offerings in healthcare, we will need to have low-cost production, high operating efficiency, and leverage partners for design, construction, and distribution. 

We believe our model is sustainable. The following elements will be in place.

• Minimal cost R&D with significant mentorship from leading researchers: Our team includes time, 3D printing capacity, testing materials, and intellectual guidance, which are all being contributed for free.

• Low-cost manufacturing: We are targeting a product that can be produced for $30 by using low-cost materials and a cost-efficient 3D printing method. 

• Existing Nonprofit organizations who can lead distribution: We will be able to leverage numerous nonprofits that are currently already working in developing countries trying to help with prosthetic needs.

• Donor network to support device production: We believe we can access enough funding to reach our 2024 goals and then, with our brand and success, would look to access larger donors to ramp up volume. 

Funding the production of these prosthetics and supplying them overseas is needed in order for this enterprise to operate efficiently For 1,000 units, the cost is estimated to be $30,000, and we are working on securing grants and other donors to support this organization at that level and as it grows. Organizations such as the Victoria Hand Project that are focused on prosthetic advancement and/or alleviating healthcare issues and poverty in developing countries will be our target for distribution. 

Alternatively, we may be able to achieve some ancillary revenue by providing the prosthetic domestically for some low price, and that revenue can subsidize the international effort.