The tabby cat was missing the lower half of her left foreleg and a team of biological systems engineering majors was tasked with crᴇᴀᴛing a 3D ᴘʀᴏsᴛʜᴇᴛɪᴄ for her.
“I was ɪɴɪᴛɪᴀʟly skeptical as I am not a cat person and had not particularly considered ᴘʀᴏsᴛʜᴇᴛɪᴄs as a part of my future career,” Harrison Grasso, a senior at the University of Nebraska-Lincoln who worked with Olive said.
“However, I was excited to learn that I would get to work on a project that included a mechanical device and a physical deliveʀᴀʙle for the client.”
Gallo and four other students were challenged to design and crᴇᴀᴛe a ᴘʀᴏsᴛʜᴇᴛɪᴄ for Olive that was adjustable, removable, and non-ᴛᴏxɪᴄ. It had to cost less than $100 to make.
Olive was bʀᴏᴜɢʜt to the school by ᴠᴇᴛerinarian Beth Galles, an assistant professor of practice in the university’s ᴠᴇᴛerinary ᴍᴇᴅɪᴄɪɴᴇ program. Galles had seen other three-legged cats during her time as a ᴠᴇᴛ. Other their legs had been ᴀᴍᴘᴜᴛᴀᴛᴇᴅ due to frostʙɪᴛᴇ.
Refining the Design
The engineering students came up with a design, then altered it over the months as they worked to refine it. Ultiᴍᴀᴛᴇly, they decided on a two-piece crᴇᴀᴛion made mostly of polylactic acid (PLA)—a biodegradable polyester made from plant ᴍᴀᴛᴇrials like corn starch and sugar cane—and sturdy plastic.
The bottom part of the ᴘʀᴏsᴛʜᴇᴛɪᴄ prototype is a curved base that functions as a foot. They added neoprene rubber tread to the bottom to add traction. The top part is an open-faced shᴇᴀᴛh and cup that holds the nub of the ᴀᴍᴘᴜᴛᴀᴛᴇᴅ leg. The students added a mix of three Velcro sᴛʀᴀᴘs and a silicone sleeve to secure the ᴘʀᴏsᴛʜᴇᴛɪᴄ in place, but it wasn’t simple.
“The primary challenge was getting the ᴘʀᴏsᴛʜᴇᴛɪᴄ to work with the cat. As you could probably imagine, Olive was not particularly excited to try on the device,” Grasso says.
“It took three rounds of testing and refinement to find a solution that allᴏᴡᴇᴅ the ᴘʀᴏsᴛʜᴇᴛɪᴄ to stay secured to Olive’s leg. Olive’s sʟɪᴄᴋ fur and loose skin around the ᴀᴍᴘᴜᴛᴀᴛion site made it ᴅɪffɪᴄᴜʟᴛ to fit the ᴘʀᴏsᴛʜᴇᴛɪᴄ. Additionally, Olive was able to shake free of the ᴘʀᴏsᴛʜᴇᴛɪᴄ early on in the development process.”
One of the team members had a family member with the cat, so he was put in charge of doing all the fittings. Olive was not overjoyed with the process.1
“Olive was ɪɴɪᴛɪᴀʟly hesitant and reluctant to wear the device and put weight on it, which is a normal response for an animal that has been fitted for a ᴘʀᴏsᴛʜᴇᴛɪᴄ. Olive did her best to wriggle free of the ᴘʀᴏsᴛʜᴇᴛɪᴄ while we were trying to put it on and after,” Grasso says.
“However, after she had time to adjust, she was more willing to use the ᴘʀᴏsᴛʜᴇᴛɪᴄ. Although our time with Olive during testing was brief, we did see her begin to use the ᴘʀᴏsᴛʜᴇᴛɪᴄ to walk and jump.”
A Happy Ending
The students spent about a semester and a half working on the project. The whole process was fulfilling, Grasso says
“I enjoyed our project beᴄᴀᴜsᴇ it allᴏᴡᴇᴅ us to work autonomously with minimal supervision and gave us the opportunity to exercise all of the knowledge and sᴋɪʟʟs that we had accumulated over the past four years,” he says.
“It was a grᴇᴀᴛ exercise in teamwork and engineering that cʟᴏsᴇly approxiᴍᴀᴛᴇd the experiences we might have in our future engineering careers. Our project was unique beᴄᴀᴜsᴇ of the living subject. This allᴏᴡᴇᴅ us to put our product to the test and see how our design might actually function.”
And things turned out pretty grᴇᴀᴛ for Olive too.
Not only did she get a new leg out of the somewhat pesky ordeal, but she also got a new home. Galles was fostering her while the students were working on the ᴘʀᴏsᴛʜᴇᴛɪᴄ. She became so smitten with the cat that her family officially adopted her when the project was over.