Custom, Affordable Swimming Prostheses

When WT alum Amy Jones Teele ’82 needed custom prosthetic swim fins, she approached WT’s Science Department Chair Graig Marx for help—and he knew just who to entrust with the special assignment: Rachel Sadeh ’19, Hannah Woo ’19, and Aria Eppinger, Class of 2020.

“Amy wanted affordable swim fins that would help her balance in the water as well as generate propulsion when she swam,” recalls Aria. “I am a swimmer, and Rachel, Hannah, and I wanted to create an athletic product for our Research Science class, so Mr. Marx introduced us.”

The trio met with Teele, a double below-the-knee amputee, to learn about her needs. They found that she had enjoyed swimming prior to amputation, and wanted to enjoy it once again.

“After her surgeries, she found it challenging to swim without a prosthetic fin of some kind,” explains Aria. “She hacked existing swim fins, those designed for non-amputees, by attaching them to her residual limbs using elastic bands, but she wanted something that would adhere better.”

The FINtastic Product

Rachel, Hannah, and Aria consulted with Union Orthotics and Prosthetics to learn about making prosthetics in general, and conducted research into prosthetics designed specifically for swimming. They learned that those that do exist have varying drawbacks, including fit, ease of use, and costs of up to $5000.

After determining that custom 3D printing could achieve the secure fit, and the ability to balance and create propulsion, that Teele desired, the students scanned her residual limbs using a 3D scanner. They implemented those scans into their fin designs using multiple CAD and 3D modeling software programs to produce a custom, 3D-printed plastic device for attaching to traditional swim fins.

They advanced through five major iterations, collaborating throughout on generating ideas and prototyping, before arriving at a final product bearing the hallmarks of each student’s unique contributions. “I connected the custom scan to our fin insert in Tinkercad,” notes Aria. “Hannah added trimlines in Fusion 360, and Rachel smoothed the surface and added the finishing touches in Meshmixer.”

Designing Around Their Client

Teele’s feedback guided the process. “Because we were designing specifically for a client, we followed her lead,” acknowledges Aria. “Whatever she wanted in the final product, we worked to put it in. For example, we had a different attachment mechanism planned for attaching the fins to her legs. However, she wanted to use silicone lined sleeves, similar to what is used on real, walking prosthetics. So we implemented her needs into our design.”                                      

The team tested their product for secure fit, water resistance, and ease of swimming.

“We went with Amy to Club One and she swam with the fins,” shares Aria. “It was amazing and very emotional. We had worked so hard to ensure that the fins would work for her. I almost cried, and Amy was overjoyed.”

Rachel, Hannah, and Aria not only met Teele’s expectations, they created a product unlike any on the market: one that combines custom 3D printing to fit a user’s residual limbs with a design that enables users to create propulsion and maintain balance in the water— “two crucial aspects of swimming not achievable with just the residual limb.” The students also point to its affordability and cost effectiveness: at $100 - $150, including labor, their custom prosthetic can be created for dramatically less than other prosthetics.

“I learned that there is a human side to STEM,” noted Aria. “It can be easy to think of science or engineering as a solitary pursuit, or just within your small group. Whether it be collaborating with other groups, working with mentors through City as Our Campus, or getting thorough client feedback, there are always many people involved in the development of a single product.”

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