Surfing Buddies Collaborate on Prosthetic Socket System: Design Aims for Adjustability and Shortened Delivery Time

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By Betta Ferrendelli

Technological advances and improvements in prosthetic sockets have progressed considerably in the last two decades. However, when it comes to designing and producing a comfortable device that can be made quickly and allow greater user adjustability, some would say there is still much room for improvement.

Current traditional fabrication methods for making a socket are time-consuming and labor-intensive. The average time from initial evaluation to final delivery is typically one month. Practitioners may be able to fabricate sockets in less than one week but may only be able to produce a limited quantity for a few patients due to the time commitment. In addition, most sockets are solid structures that lack any dynamic change capability.

Colleagues, business partners, and long-time surfing buddies Garrett Hurley, CPO, and Andrew Pedtke, MD, an orthopedic surgeon, have been working on a new socket system design they hope will change that.

A Literal Board Meeting

Hurley and Pedtke met several years ago at the University of California, San Francisco (UCSF) when Pedtke was in his first year of orthopedic surgery residency and Hurley was working as a prosthetist. Given the nature of their jobs, the two worked together closely, and before long, began surfing together and became friends.

"It was during our time surfing when we really started to collaborate and talk about working together," Hurley says.

Pedtke remembers a particular day when the two met at a café after surfing. "I discussed with him some surgical concepts I had for medical device development, and then we simply said why not pool our ideas, start a company, and develop these concepts over time," Pedtke says. "We felt it would be best to hold onto these ideas and develop them ourselves, because that way we could control the process and really create the best product for the user."

Design sketches are used to help work out concepts for improving comfort. Photographs courtesy of LIM Innovations.

Juan Cespedes looks at digital plans for creating sockets.

Hurley and Pedtke initially recruited an industrial designer and a materials scientist. "Once we had this small core of people, some real turnkey solutions became realized and some traction started to push the business forward on all ends, from intellectual property, business, to product development," Pedtke says.

The end result was LIM Innovations, San Francisco-a company Hurley and Pedtke cofounded in October 2012 to develop what they now call the Infinite Socket-a socket designed to help practitioners fit sockets in a more efficient and effective way in order to improve patient care and workflow.

The founders, who both have extensive experience working nationally and abroad with patients with amputations, say that they recognized the clinical significance of the prosthetic socket and that there was a need in the prosthetic socket market.

Hurley, who began working on socket innovations more than a decade ago, says that the new socket design aims to improve clinical outcomes and versatility through a blend of structural design, manufacturing techniques, and proprietary materials, and could take as little as 24 hours from evaluation to final delivery. Among the benefits it will offer are increased comfort, control, heat dissipation, and moisture management. It will also accommodate daily volume fluctuations for the user, thus preventing excessive adjustment visits to the prosthetist.

Hurley checks materials.

An area that Hurley says is often overlooked by O&P professionals with regard to design is the inconsistency of the human body. "The human body often changes in size and shape over time. Current prostheses lack the ability to change with the patient," he says.

One of the main values of the socket, according to Hurley, will be its adaptability. "This socket system is applicable to many different socket approaches, different suspension mechanisms, as well as different socket shapes," he says. "Therefore, practitioners will still be able to apply their skills and preferences to meet the patient's needs...."

Practitioners will need to be a certified LIM clinical partner to order a socket and will have to provide a mold or CAD file plus patient data, such as weight and activity level, Hurley says. "Our focus is not about a socket that can direct mold; it is different...than that," he says, adding that their sockets will "completely adhere to the descriptors of existing L-Codes for prosthetic sockets, socket replacements, and add-on codes." According to Hurley, "The Infinite Socket promises to offer versatility that has yet to be seen. The payoff of this innovation's advantage for practitioners includes a more efficient and effective way to get from evaluation to final delivery."

Research and Development Continues

Hurley and Pedtke continued testing their socket prototype in early 2014 with about 30 patients. Though they started the company with people who have transfemoral and knee disarticulation amputations in mind, the socket system is applicable to all levels of amputation, says Pedtke, the company's CEO. LIM is reaching out to those with amputations through a network of individuals with whom it has worked, he says.

Hurley and Geoff Turner examine prototypes in the lab.

One of those patients is Geoff Turner, 49, who lost his right leg at the knee when he was struck by a car one night on an Australian highway nearly 25 years ago.

"The benefits of [the] LIM socket are felt immediately by the amputee," says Turner, who, as a long-time patient of Hurley's, has worked closely with him on some design modifications and ideas for improvements to prosthetic sockets. Turner became associated with LIM as one of the initial test patients, and was asked if he would be interested in an executive role while on a business trip with the company in early 2013. "Being passionate about the product, I happily agreed," says Turner, who is the chief operating officer, in addition to being a board advisor and lead product tester.

Turner says that the increased comfort made possible by the modular construction and level of adjustment of the Infinite Socket are "dramatic improvements" over traditional socket offerings. "The ability to wear my prosthesis all day without even thinking about it-well, that's probably the most profound difference," says Turner, a runner and triathlete who competes at local and national levels.

Turner says that the ability to adjust his socket "on the fly" is one of the best advantages of the system. "I don't find myself needing to fuss with the socket the way I would a traditional one," he says. "[T]here is no need to go to the bathroom at work to take off my leg and add or remove a stump sock. If I have volume change in my stump during the day, a simple adjustment is all I need."

The ease of that adjustment for Turner was recently reinforced when he had to return all of his LIM socket prototypes for development purposes and was forced to wear one of his traditional sockets. "I was shocked to find that a socket that I had previously considered to be, if not perfect, at least quite comfortable, was, by comparison...virtually unwearable at this point," he says.

Gaining Exposure

In June 2013, LIM won a pitch competition at the 21st annual Medical Device Conference in San Francisco. The "MedTech Idol" competition showcases early-stage medical device companies to bring them to the attention of the medical and investment communities, says Pedtke, whose plan was to go into tumor/limb salvage surgery, but is now focused on running LIM Innovations. LIM, one of 65 entrants, won the competition after being voted to have the most outstanding medical technology opportunity, he says.

Pedtke, Hurley, and Turner say they are pleased with the exposure that winning the competition has had for the company. "I was part of the team that night," Turner says, "and it was exciting to see the product that I had already invested in personally achieve such recognition."

The company continues to move toward an unveiling date for the LIM Infinite Socket system later this year, with a target launch at the American Orthotic & Prosthetic Association (AOPA) National Assembly & Scientific Symposium in Las Vegas, Nevada, on September 4.

Betta Ferrendelli is a freelance writer based in Denver, Colorado.