Usually months elapse between below-knee amputation surgery and the time that the patient is able to be up and moving about on a prosthesis or artificial leg.
But a device designed by a team of University of New Mexico students promises to significantly reduce that time and enhance the healing process.
Called the Limitless Socket, it is intended to fit on the end of an amputated limb and be connected to a prosthesis, an artificial leg or foot.
The design won the $50,000 prize in the 2017 UNM Biodesign Program competition. The money – $25,000 from the university’s School of Engineering and $25,000 funded through a pilot grant award from UNM’s Clinical and Translational Science Center – will be used by the winning team to develop a prototype and test it.
“Right now, it can take three to six months for a patient to be up and using a prosthesis,” said Christina Salas, the UNM assistant professor whose class in biodesign is the basis for the competition. “We are looking at getting people up on this socket in weeks.”
A major factor in that diminished time is that the Limitless Socket reduces direct contact on the amputated limb.
“This crosses over the knee, transferring the load to the knee and the femur,” Salas said. “That enables the patient to be up much sooner and using the prosthetic, and the sooner you are up and around, the better it is for healing and mobility.”
Physicians would also be better able to monitor the wound during recovery because of the new design.
“The limb is suspended in a sort of net basket that allows for the detection of swelling and the draining of fluid,” Salas said.
And, due to ratcheting components, the Limitless Socket can be easily adapted to the condition of the amputated limb, which is important, because the volume and shape of the limb changes during the healing process.
Members of the winning Limitless Socket team are Jane Nguyen and Victoria Lujan, both undergraduate students in chemical engineering; Matthew Rush, a doctoral student in nanoscience and microsystems engineering; and Evan Hagin, a master’s student in mechanical engineering.
Hagin said he wanted to be part of the Limitless Socket team, because he believes it holds real promise for use in the medical field.
“Interestingly enough, I’ve had a lot of medical problems in my life, and I wanted (a project) I felt would really help,” said Hagin, 30. “I was looking at designs that would be practical in the time available to us and which would be the most marketable.”
The new socket is intended for use from immediately after surgery, until the point when the patient is fitted with a final prosthesis. Usually that is a period of about one year, but Salas said it is hoped that the Limitless Socket technology could shorten that time by three to five months.
Salas has a doctorate in biomedical engineering and a master’s in mechanical engineering, both from UNM. She is on the staff of UNM’s department of orthopaedics and rehabilitation with joint appointments in the departments of civil engineering and mechanical engineering.
Salas has been teaching at UNM for more than three years, and, in each of those three years, her fall class in biodesign has featured a competition to develop designs that will facilitate medical practice in certain areas.
The first year it was trauma, the second year it was emergency medicine and this year the goal was to tackle deficiencies in medical technology that present barriers in physical medicine and rehabilitation.
Students in Salas’ biodesign class come from different disciplines, most of them from engineering, but some also from biology and the school of medicine. They were divided into four teams of four or five students each for the 2017 competition.
“They went to physical medicine and rehabilitation clinics, some here at UNM, also UNM athletics and the Lovelace UNM Rehabilitation Hospital,” Salas said. “They learn what problems exist in the field, problems they can solve to make the physicians’ jobs easier or to help patients. They spend about a month on this, and then they take all the information they have learned to determine what projects are worth pursuing (for presentation) to start-up companies or for licensing to established companies.”
In addition to the Limitless Socket, other projects entered in the competition this year included:
• The Prime Suit: A tight-fitting suit with synthetic muscles that is worn beneath clothes and is designed to stabilize a person with balance issues.
• Mild Traumatic-Brain-Injury Patch: A wearable patch that draws small samples of fluid from the skin, enabling the rapid detection of mild traumatic brain injuries such as concussions.
n PURIST: That stands for Pressure Ulcer Relief Involving Streamline Telehealth and is the name given to a mat designed to detect the potential for pressure ulcers or bed sores in patients confined for long periods of time in beds or wheelchairs. The mat is intended to respond by moving away from a person’s skin to relieve pressure.
“They were all great technologies,” Salas said.
Students selected the technology that intrigued them most, and teams were formed accordingly.
Hagin said he was attracted to the process required to make the socket.
“I liked the idea of working on something that is actually physical, actually building something because that’s my specialty as a mechanical engineer,” he said.
Team member Rush, 30, said the Limitless Socket was not his first-choice project, but he soon became enthusiastic about it.
“Ultimately, I saw a lot of potential in it,” he said. “We won because (the judges) could clearly see the application of the project.”
The judges were Andrew Shreve, director of UNM’s Center for Biomedical Engineering; Eric Prossnitz, professor of internal medicine and biodesign program coordinator at UNM’s Health Sciences Center; Rebecca Dutton, assistant professor in UNM’s department of orthopaedics and rehabilitation; and John Chavez, president of the New Mexico Angels, a group focused on investing in early-stage companies in the Southwest.
Hagin said he and his team members are determined to see the testing and development of a Limitless Socket through, even if that means staying in touch by phone and email in cases where one or more of the team leaves UNM for work or study elsewhere.
“I was really happy about how everyone was very excited and really committed to working on it for the next year, committed to pushing this forward,” he said.
Rush sees the project as something that fits exactly into his plans for his future. When he completes his doctorate at the end of this semester, he intends to do post-doctoral research work at Northern Arizona University, then go to medical school somewhere, hopefully in 2019.
He said he wants to help fill what he sees as a gap in communication between scientists/engineers and physicians.
“We can design anything out there,” Rush said. “The hard part is determining what to design for. I am willing to become a physician to work with engineers and scientists to design things that will help the health care field. I’m hoping the Limitless Socket will become a common socket for lower-leg amputations.”