Glenn Klute, PhD

Building a Better Lower Limb

Researcher Glenn Klute, PhD, left a career in aerospace engineering in favor of bioengineering—and O&P

O&P Almanac introduces individuals who have undertaken O&P-focused research projects. Here, you will get to know colleagues and healthcare professionals who have carried out studies and gathered quantitative and/ or qualitative data related to orthotics and prosthetics, and find out what it takes to become an O&P researcher.

This prototype, developed in collaboration with Charles King, CPO, expels perspiration from the skinliner interstitial space. The subject is about to step into a thermal chamber at 95°F to walk for 30 minutes.

GLENN KLUTE, PHD, STARTED his career not in O&P, but in aerospace engineering. He studied mechanical engineering as an undergraduate at the University of Washington (UW), and his first job out of college was designing cruise missile systems.

“While I believe in a strong national defense, I didn’t want to be the one making better bombs,” he says, explaining why he switched fields. “When no one would hire me to design medical devices, I went back to school to study bioengineering—first for a master’s degree at Pennsylvania State University and later for a doctorate at UW.” That path eventually led to robotic systems and technology that could be applied to help people move. “We’re still a long way from making an equal to the human limb, but that’s what makes the research interesting.”

Today, Klute is a research career scientist at the Department of Veterans Affairs (VA) and affiliate professor at UW. Specifically, he is associate director of the Center for Limb Loss and Mobility (CLiMB) at the Seattle VA, where he also conducts research to improve the mobility of individuals with lower-limb amputation. His responsibilities at UW include teaching occasional classes and supervising graduate students from a variety of academic departments, including mechanical engineering, bioengineering, electrical and computer engineering, and rehabilitation medicine.

Groundbreaking Research

Klute’s research focus over the years has migrated to lower-limb prosthetics, rehabilitation engineering, and biomechanics. “Lower-limb prostheses are the application; developing them uses method from rehab engineering; and biomechanics are some of the metrics used to measure their performance,” he explains.

“Sometimes our research is focused on comparing different commercial products to see how well they work. Providers and payors appreciate these results—because why would you want to prescribe or pay for something that doesn’t work?” he says. “Other times, we’re developing something new because there isn’t anything out there meeting the need. Patients and manufacturers appreciate this work because it shines new light on what might be possible.”

Some of Klute’s early investigations related to socket technology. “Two decades ago, a university colleague was giving me a hard time about not working on problems related to sockets and suspensions. She was right

when she said it was one of the most important things we could be doing as researchers,” he recalls. “While ‘goodness of fit’ remains hard to measure, I started in on the easy things like skin temperature and perspiration. Manufacturers are now addressing these problems in earnest, and I like to think we helped get the ball rolling.”

Now, Klute is developing a novel device called the Pivot-Flex Foot. “Most people walk with a subtle little ‘hitch in their giddy-up.’ In clinical terms, the tibia and fibula rotate slightly in the transverse plane during the stance phase of gait while the foot rotates in the sagittal plane. Engineers call this simultaneous movement ‘coupled motion,’ but currently available lower-limb prostheses don’t do this,” he says. Instead, most prostheses rely on spring-like behavior in the sagittal plane; some have it in the coronal and transverse planes, but “none provide coupled motion where one motion forces the other,” he explains. Klute’s team has patented the technology, which is currently in the testing phase in the lab and in the community.

“What is exciting is how the O&P profession has raised the bar on adopting new products,” Klute says. “Every prosthetist we’ve talked to asks about evidence: ‘Show us how well it works.’ It really demonstrates how the O&P community has evolved and demands more than just marketing.”

Klute also is working on an “interesting problem” that involves leveraging machine learning methods to measure how a person walks, and quickly adapting the power output of a prototype-powered limb to respond appropriately. “When we first started this work, I felt behind on the technology because I had attended a national high school science fair in 2017, and it seemed like every other project involved machine learning,” he says. “These high school students were doing some innovative work, and it was simply inspiring. This prototype limb can invert and evert to conform to uneven terrain. Reflective markers (gray spheres), visible as bright spots in infrared light, reveal how a limb moves in response to changes in terrain.

Ferrier Coupler Options! Interchange or Disconnect

The Ferrier Coupler provides you with options never before possible:

Enables a complete disconnect immediately below the socket in seconds without the removal of garments. Can be used where only the upper (above the Coupler) or lower (below the Coupler) portion of limb needs to be changed. Also allows for temporary limb replacement. All aluminum couplers are hard coated for enhanced durability. All models are interchangeable.

Model A5

The A5 Standard Coupler is for use in all lower limb prostheses. The male and female portions of the coupler bolt to any standard 4-bolt pattern component.

The F5 Coupler with female pyramid receiver is for use in all lower limb prostheses. Male portion of the coupler features a built-in female pyramid receiver. Female portion bolts to any standard 4-bolt pattern component.

The Ferrier Coupler with an inverted pyramid built in. The male portion of the pyramid is built into the male portion of the coupler. Female portion bolts to any 4-bolt pattern component. NEW! The FA5 coupler with 4-bolt and female pyramid is for use in all lower limb prostheses. Male portion of coupler is standard 4-bolt pattern. Female portion of coupler accepts a pyramid.

NEW! The FF5 has a female pyramid receiver on both male and female portions of the coupler for easy connection to male pyramids.

NEW! The FP5 Coupler is for use in all lower limb prostheses. Male portion of coupler has a pyramid. The Female portion of coupler accepts a pyramid. The Trowbridge Terra-Round foot mounts directly inside a standard 30mm pylon. The center stem exes in any direction allowing the unit to conform to uneven terrain. It is also useful in the lab when tting the prototype limb. TheThe unitunit isis waterproof and has a traction base pad.

Model FA5

Model F5 Model FF5

Model P5 Model FP5 Model T5

Before prototypes are tested with volunteers, Glenn Klute, PhD, and his team conduct bench tests to improve designs and validate expected performance. Here, Klute makes an alignment adjustment before a laboratory proof load test.

You don’t have to be an early adopter, but you can catch up quickly. Working with new approaches like 3D printing can make your work more interesting and may lead to innovations that help with your practice and meet your patients’ needs.”

Collaborations and Inspirations

Working at both CLiMB and UW means that Klute interacts with a wide range of colleagues, students, and O&P consumers who inspire his work.

“The University of Washington has been the source of many talented graduate students who have played key roles in my O&P research,” he explains. “Their enthusiasm, dedication, and scholarship are inspiring.”

He also appreciates the veterans with lower-limb loss who volunteer to participate in his studies. “Their willingness to try new technologies and provide meaningful feedback has been important,” he says. “Without people to give your ideas a try, you really don’t have much. The VA has played a key role in helping us reach out to these veterans.”

When he considers the future, he believes developing prostheses that improve mobility for users will continue to be key. “In the short term, providing comfortable and well-fitting socket and suspension systems has been and continues to be a challenge,” Klute explains. “In the long term, developing neural interfaces that can actuate prosthetic systems and provide proprioceptive feedback is an exciting area.”

He predicts that wearables and data science will inform O&P researchers and will be essential to future investigations because these innovations “tell us so much more about what people do with their prostheses and where we need to improve,” he says. Together with patient interviews and survey responses, “we’ll have helpful tools that tell us where further development is needed.”

To ensure the future of O&P research, he notes the importance of funding. His own funding has led him to prioritize lower-limb mobility. “Since my funding comes mostly from the Department of Veterans Affairs and the Department of Defense, my target population is the adult capable of ambulation,” he says. “Across the spectrum of these individuals, whether you lost your lower limb from trauma or complications from diabetes/dysvascular disease, you really want your pre-amputation function back. If you’re capable of walking, we’re trying to help.”

NOTABLE WORKS

Glenn Klute, PhD, has been involved in dozens of published studies, including the following: • Segal, A.D., Kracht, R., Klute, G.K. “Does a Torsion Adapter Improve

Functional Mobility, Pain, and Fatigue in Patients With Transtibial

Amputation?” Clin Orthop Relat Res, 2014; 472(10):3085-92. doi: 10.1007/ s11999-014-3607-9. PMID: 24733445; PMCID: PMC4160517. • Klute, G.K., Huff, E., Ledoux, W.R. “Does Activity Affect Residual Limb Skin

Temperatures?” Clin Orthop Relat Res, 2014; 472, 3062–3067. doi.org/10.1007/ s11999-014-3741-4. • Pew, C., Klute, G.K. “Design of Lower-Limb Prosthesis Transverse Plane

Adapter With Variable Stiffness.” ASME J Med Devices, 2015; 9(3): 035001. doi. org/10.1115/1.4030505. • Klute, G.K., Bates, K.J., Berge, J.S., Biggs, W., King, C. “Prosthesis Management of Residual Limb Perspiration With Subatmospheric Vacuum Pressure.” J

Rehabil Res Dev, 2016; 53(6):721-728. doi: 10.1682/JRRD.2015.06.0121. PMID: 27997669. • Srisuwan, B., Klute, G.K. “Locomotor Activities of Individuals With Lower-

Limb Amputation.” Prosthet Orthot Int, 2021; 45(3):191-197. doi: 10.1097/

PXR.0000000000000009. PMID: 33856151; PMCID: PMC8494105.