A program in which students at the University of Hartford fabricate prostheses combines research and the practical to help veterans with leg amputations to enjoy scuba diving.
Graduate students in the prosthetics and orthotics program also are learning how to use melted polypropylene to wrap a model leg — cast from one of their fellow students — and to cut and smooth it to make an orthotic. It’s not easy to take a 350-degree sheet and wrap it around a plaster cast, with no wrinkles.
They work at the Hanger National Labs in Cromwell, surrounded by feet and legs made of plaster.
Working with the Combat Wounded Veterans Challenge in Florida, their professors, Matthew Parente, director of the program, and associate director Duffy Felmlee are working with veterans in Key West, giving them prostheses that act like flippers or rudders, making it easier to swim underwater.
“Traditionally, our prosthetic devices aren’t intended for scuba purposes, said Emily Dow, a second-year student from Moretown, Vermont.
“So there’s some challenges that present themselves that we’re working to solve. A great example of one is a lot of our componentry isn’t designed for water,” she said.
“Each prosthesis is made up of a socket, which is the custom part of the prosthesis that goes on the limb, and then all the machinery underneath it are the parts … Those are what we refer to as components,” Parente said.
Each component must be rated according to its weight, so the prosthesis is balanced, he said, “whether they’re made of stainless steel, titanium, an alloy or whatnot. But usually the primary focus is for land-based activities.”
The challenge is to make them underwater friendly.
Another concern is, “a lot of times when you put all this componentry together, things aren’t very energy efficient,” said Taylor Rivers of Swansea, Mass. “So [we’re] looking at just energy expenditures and how to save that energy consumption as these amputees are in the water, so they are able to do more.”
A below-the-knee amputee will have to spend 25% to 30% more energy with a prosthetic, Parente said.
“For an above-the-knee amputee it can be up to 70%, so for me putting on a backpack of 105 pounds to have to walk a mile would take a lot more energy for me to do that task.” Parente said. “So that’s the energy expenditure side.”
A large part of the reason it takes more energy is because the large muscles in the hip must be used to move the prosthesis, which use more energy than the smaller muscles in the leg and foot.
Once the prostheses are fabricated, they are brought down to Florida, where the research, aided by an independent donor, is conducted.
“Land activities for any of our patients is always challenging,” having to get around obstacles and deal with gravity, said Felmlee, lead investigator of the study.
“We put individuals into a gravity-reduced environment and then underwater, and now they’re able to perform kick activities and things on a more level playing ground with non-amputees,” he said. “So we eliminate gravity, make everyone float and [they] can participate in other things.”
One of those things is restoring coral reefs off the Florida keys by attaching coral buds to PVC trees.
Felmlee said the standard in the military is not to use a prosthesis while swimming. “One of our goals would be to start to encourage the dive community to use the prosthesis,” he said.
“When you talk to most of our divers, they go through their training without the use of the prosthesis. And our findings are that they should be using it to try to maximize efficiency, air consumption and a couple other things,” he said.
When it comes time to research the prostheses, to see how they can be improved, Felmlee, Parente and a third investigator from Kentucky “box up all of our instruments, the prototypes, all that stuff, and then we fly south down to Key West, and then we have a 48-hour period of data collection,” Felmlee said.
Each swimmer does the same routine, both with and without the prosthesis, Felmlee said. “We set up the dive environment, which has these obstacles and a couple of things underwater where they have to swim so we can keep them uniform,” he said.
Then sensors are placed on the shin, thigh and lower back, if they are not double amputees.
“So then we just collect that … and you let the subjects do their thing. They have to swim this pattern, and then we change up a couple of different things,” Felmlee said.
They will ask the test subjects how it felt to swim with and without the prosthesis and then go back to UHart to analyze the data, in order to improve the apparatus.
“The industry standard right now is not to use the prosthesis, which we understand from a safety standpoint,” Felmlee said. To an instructor it’s “just another piece of equipment that could go wrong.”
“But what we hear from our divers, novice and experienced, is that when they’re in open water outside of the pool environment for training and testing, having that prosthesis really helps them when they get caught in a current and all that type stuff,” he said.
He hopes the word will get out and that people will contact the wounded veterans group or UHart to promote the devices and to improve the prostheses further, “and then also to relay the information from our group of divers and put that information out there for the public to read. … See, this guy does it. I can do it, too,” he said.
Felmlee said the fins are standard commercial rubber flippers that attach to a carbon-cast foot at the end of the prosthesis.
“They’re not specific to prosthetic use. It’s the same stuff any diver would use,” he said.
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