We’ve seen advanced prosthetic legs come to market over the last decade and many new devices are in the works. Yet, perhaps the biggest challenge to patients relying on these products is not the limits of their distal portions of the prosthetic leg, but the interface between the residual limb and the prosthesis. The Infinite Socket from LIM Innovations, a company based in San Francisco, is a new approach to fitting prostheses that leverages digital technology and adjustable design to match each patient’s unique needs. We spoke with Dr. Andrew Pedtke, the cofounder of LIM Innovations, to learn more about the company’s technology and how it’s revolutionizing the lower prosthetic market.
Medgadget: Tell us about LIM Innovations and what led you to develop the Infinite Socket?
Dr. Andrew Pedtke: My co-founder, Garrett Hurley and I, had been working with amputees and were frustrated with the limitations of current prosthetic technology due to the arduous manufacturing process and lack of measurable patient outcomes. Garrett (a certified prosthetist) and I joined forces in 2012 to create LIM Innovations and our first product, the Infinite Socket.
We identified the overlooked areas in prosthetics, particularly the interface where technology meets the human body. We deconstructed these lynchpin areas, which once held back the user, clinician, and industry as a whole. Our efforts led to LIM Innovations – a company focused on human functional experience. LIM Innovations is providing a conceptual framework of how we view physical function for amputees. The Infinite Socket is the first device, in a series of products, to empower amputees to live beyond the limits of their prosthesis.
Medgadget: The problem of poorly fitting sockets has existed for a long time. What is your solution and why do you think it’s being realized only now?
Dr. Pedtke: Rather than altering existing technology to drive change, we deconstructed the problem with traditional socket technology to create the Infinite Socket. Traditional sockets can be likened to a wooden clog – a fixed, rigid shape, that does not change with the user’s residual limb. The Infinite Socket is like a running shoe – a combination of advanced materials and adjustable systems, empowering clinicians and users to adjust the prosthesis in response to volume and shape change at the residual limb.
Our team at LIM Innovations identified a variety of pain points hindering amputees and clinicians with traditional prosthetic sockets. By creating a custom, modular and adjustable device, we have empowered amputees and clinicians to control and optimize the fit of the prosthesis. Each component of the Infinite Socket is fine-tuned to meet the specific anatomic and biomechanical needs of users residual limb.
Medgadget: Have the limitations been due to a lack of good ideas or of appropriate materials and other technologies?
Dr. Pedtke: It is not necessarily a lack of good ideas, but rather a general oversight of what is possible.
Despite the glaring need to advance prosthetic socket technology, considerable attention has been placed on distal components. Traditional prosthetic socket technology and methods have seen little advancement in the last 50 years, while distal components have developed rapidly.
The consistent development of distal components at the expense of the prosthetic socket is propagating and limiting. Distal components behave through predictable scientific and engineering principles, utilizing metrics surrounding gait-analysis and step-count to measure patient outcomes. The prosthetic socket is bound by an intimate interplay with the human body. This dichotomy skews the future development framework in prosthetics, creating an incomplete and inaccurate picture. Existing metrics drive development of distal components, while prosthetic socket development is ignored. Bringing the industry to a new standard requires forward thinking, technology with unique metrics, and a defined spectrum of functional outcomes and end-user satisfaction.
Outcomes are often defined by the several steps taken in the prosthetic clinic to demonstrate ideal gate. The satisfaction in his or her integration to life outside of the healthcare setting is often secondary to step-count and the immediate gait-analysis conducted in the clinic.
At LIM Innovations we’re reorienting the conceptual framework to improve function for millions of amputees. The science of engineering is in constant interplay with the art of human experience to prevent limitations. For us, function is analyzed and categorized as its own entity, driving design and engineering. User needs and feedback are the catalyst behind product development and laying the framework for functional outcomes.
I have a sound understanding of the functional deficiencies and how the remaining anatomic structures are likely to behave and perform after an amputation. Mr. Hurley is able to isolate and compartmentalize the functional purposes of various areas of the prosthetic socket along a range of patient indications. Capturing the multiple anatomies of a residual limb requires microscopic and macroscopic dynamic solutions, juxtaposed to a rigid frame designed purely to support the skeletal system.
Medgadget: Can you tell us about some success stories of people using the Infinite Socket?
Dr. Pedtke: We have a variety of users, including children, veterans, active duty military personnel, and Paralympic athletes. While our users span the spectrum of function and ability, two of our biggest success stories are two young and healthy users, who lived a sedentary lifestyle prior to being fit with the Infinite Socket.
We met a healthy amputee in his 20s who couldn’t walk more than one mile, despite having a sophisticated microprocessor knee unit attached to his traditional socket. He relied on what he called a 3-for-1 schedule: for every day he spent on his prosthesis, he spent the next three bed-ridden or confined to a wheelchair.
His clinician’s snapshot of his function in the clinic satisfied the outcomes the industry aims to achieve, but his quality of life was limited by his ability to ambulate. The underlying issues from outside the clinic, such as discomfort and the ability to perform routine functions, were masked by the emphasis on gait-cycle and high step-count in the clinic. Without better socket options to expand his full functional capacity, his outcome was defined by his ability to ambulate, not time spent living a functional, quality lifestyle.
Our team also met a 14-year-old pediatric user. He was diagnosed with vascular malformations in his leg when he was seven years old, and was unable to walk for the next seven years of his life. In an attempt to control the disease, he had nearly 46 surgeries, prior to deciding to amputate his leg.
He received a traditional laminated socket when he amputated his leg and expected to get his life back. However, the traditional socket did not provide an optimal fit to help him back to an active lifestyle. His mother mentioned moments where he would go to school with his prosthesis on, only to resort to a pair of crutches by days end.
After he was fit with the Infinite Socket, his mother recalls pulling up to school to pick him up, and seeing him walk out with his backpack slung around his shoulder and a big smile on his face. The Infinite Socket has helped him regain the function and activity he desires and live beyond the comfort of his prosthesis.
Medgadget: What about from the clinician’s perspective? How is your technology going to affect how rehab specialists work with their patients?
Dr. Pedtke: The Infinite Socket is a custom, modular device intended for scalable socket fabrication. The prosthetic industry is an anomaly in the medical space, because prosthetists create their medical devices. It is a combination of art and science, putting the burden to provide care and create the devices on the prosthetists shoulders.
You do not see surgeons, cardiologists, or dentists creating the devices used in their practice from scratch. Prosthetists spend a large portion of their time creating the devices they use in their practice, rather than spending time with the patient to achieve an optimal fit for functional outcomes.
The Infinite Socket reduces the fabrication time and maximizes the clinician’s ability to customize and make adjustments on demand to achieve optimal functional outcomes for their patients. Its simplicity will allow for more integration with the patient in the rehab space with quicker return to function and less down time during the fitting process.
Medgadget: What are you looking forward to in the future and how is your company working toward improving your products to help as many people as possible?
Dr. Pedtke: The product development side of things continues to go forward at light speed. We are working closely with the US military, developing advanced socket and interface solutions for war-injured veterans. We hope this will have widespread application to the marketplace for civilians as well.
I am particularly interested in developing better outcome metrics and tools to measure them. The industry does not currently have a strong foundation of tools and measures in place to demonstrate efficacy in both patient satisfaction, functional improvement, and cost effectiveness. These foundations need to be developed to improve the standard of care and evolve the industry.
There is a knowledge and technology gap between sophisticated devices and functional user outcomes. Prosthetic technology faces a conceptual challenge in marrying highly-engineered devices and baseline functionality to create tangible effects on usability and improved quality of life.
The above-knee prosthetic socket represents one of the greatest technology gaps in the healthcare industry. There is a strong juxtaposition between the prosthetic socket and advanced distal components such as microprocessor knees, running blades, and powered-ankles.
It is our job, as healthcare professionals, to bridge the gap and develop a better foundation for better functional outcomes.
Product page: Infinite socket…