Adapting Fabrication Skills With Changing Technology

Home > Articles > Adapting Fabrication Skills With Changing Technology

As O&P fabrication materials, methods, designs, and componentry continue to evolve, O&P technicians and practitioners may find they are challenged to keep pace. The O&P EDGE asked experts for their insight into how to take advantage of useful new developments.


Luis Cordero, senior prosthetic technician, Össur Orlando Custom Fabrication.
Photographs courtesy of Össur Americas.


Some Trends in Socket Technology

Socket designs in recent years have trended away from traditional rigid sockets toward designs with more flexibility, adjustability, and comfort, which may require different fabrication techniques.

RevoFit™, Click Medical, Steamboat Springs, Colorado, uses a technology that integrates custom panels and a Boa® reel and cable system into the fabrication of the prosthetic socket. Using the reel to make micro-adjustments to the cable, the wearer can adjust the panels for compression, suspension, and closure around the residual limb to allow for volume fluctuation and comfort. As with other specialty sockets, the RevoFit has its own unique fabrication approaches that are recommended, such as including an inner flexible socket to allow for even pressure when adjusting panels and using one of several methods to bond the Teflon® guide tube through which the cable is threaded to the socket. Examples of these methods are discussed in "Fabrication Using the RevoFit Lamination Kit" (The O&P EDGE, May 2015).

The High-Fidelity™ (HiFi) Interface, biodesigns, Westlake Village, California, for upper- and lower-limb prosthesis users, provides "a high level of intrinsic bone control as the interface captures and reproduces skeletal motion," according to the company's website. Designed by Randy Alley, BSc, CP, CEO, the interface is compatible with all suspension techniques. The device training, which is available via webinar, stresses fabrication flexibility in the design, leaving the embodiment and materials up to the practitioner. A unique paddle system is used during casting or scanning of the limb, allowing the patient to actively participate in his or her fitting while providing immediate feedback. HiFi sockets are micro- and macro-adjustable and can be created in-house or sent to an authorized HiFi fabricator, Alley notes.

LIM Innovations, San Francisco, describes its Infinite Socket™ as "a versatile, custom-molded, modular socket designed to provide maximum clinician, as well as user-initiated, adjustability to accommodate daily volume fluctuation." While the sockets are fabricated in the company's central fabrication facility from orders placed by practitioners, the procedure used in their production represents another way in which socket design may continue to impact fabrication skills and techniques as new developments arise.

As described in a story by Kyle VanHemert on the Wired website (, to create an Infinite Socket, the patient's limb is scanned. Computer software is then used to model four struts forming the socket's rigid frame. The struts are made from carbon fiber strips that are heated and put into place with a modified CNC machine. An acrylic-based carbon fiber is used, which allows the struts to be reheated and reshaped later if necessary. The struts are held together at the top by the soft-goods interface, which is a thick foam cuff. Multiple tensioning systems are available: a ratchet closure, a hook-and-loop Velcro™ system, and the Boa reel and cable system.

NU-FlexSIV Socket

An innovative socket design, the Northwestern University Flexible Sub-Ischial Vacuum (NU-FlexSIV), was developed to meet the needs of highly active individuals, explains codeveloper Ryan Caldwell, CP/L, FAAOP.

Lower proximal trim lines prevent the socket from impinging on the pelvis; a flexible design increases sitting and activity comfort. Vacuum pump suction plus compression from an undersized liner and socket secure the socket firmly and decrease in-socket limb motion. Research using the socket comfort score, gait analysis, and clinical outcome measures shows that socket comfort is greater and hip range of motion increases compared to an ischial containment socket; clinical outcome measure performance is comparable.

Codeveloper Stefania Fatone, PhD, BPO (Hons), associate professor with Northwestern's Department of Physical Medicine and Rehabilitation, helped Caldwell further develop the socket, including writing course materials to teach design application and testing the socket's function—work that was partially funded through a U.S. Department of Defense (DOD) grant awarded to Fatone as principal investigator. Fatone and Caldwell are evaluating socket performance and comfort more fully in a randomized crossover trial funded by another DOD grant. They provide a webinar on the NU-FlexSIV socket through the American Academy of Orthotists and Prosthetists Paul E. Leimkuehler Online Learning Center and provide two-day hands-on courses through a Northwestern University sponsorship agreement.


Technicians at work in the Össur Orlando custom fabrication lab, which offers fabrication of NU-FlexSIV sockets.


The NU-FlexSIV system is relatively simple and reproducible, employing a fabricating process that can be accomplished in most O&P facilities and easily taught to others, Caldwell says. The NU-FlexSIV has some specific fabrication requirements, Caldwell notes. The socket starts with a firm silicone liner foundation to preload the limb's soft tissues. Then, the socket consists of a flexible inner socket and a rigid frame to allow for sufficient flexibility while the wearer is in a seated position, and to protect the liner and sleeve. "In order to seal the reflected liner properly to the outer surface of the flexible socket wall, the rigid frame must be lowered to allow the seal," Caldwell explains. "The rigid frame can be made based on the patient's body weight and activity level using either standard carbon or fiberglass laminations, but the flexible inner portion of the socket needs to be firm enough to support the body weight without excessive splaying or loss of shape. The two materials we currently recommend are the Össur Medi Flex EVA and the Orfitrans Medium Soft."

Editor's note: Space constraints do not allow us to include all socket designs that may impact technical skillsets.

New Materials

A variety of technologies being developed may be heading into the O&P realm, including gold nanoparticle artificial skin that can sense touch, humidity, and temperature at the same time; other materials using nanotechnology; artificial muscle tissues; eco-friendly bioplastics made from plants; and more. A development in recent years is a polypropylene-based composite that is stabilized with discontinuous carbon fiber called ProComp. The material was developed by Gary Bedard, CO, FAAOP, and is exclusively distributed by Cascade Orthopedic Supply, Chico, California. The individual fibers allow the composite to flow and stretch during melt-temperature vacuum forming. The material, with zero carbon surface protrusion or shrinkage due to carbon, features a 3D carbon matrix core and provides improved structural integrity and clinical increased stiffness, according to Cascade's website. "The carbon fibers are enclosed within the polypropylene, so there is no exposure risk," says Phillip Harrison, CP, clinical services manager, Cascade Orthopedic Supply. The material is made of three layers of polypropylene with two layers of carbon fiber matrix sandwiched in between, he explains.

The 3D random placement of the carbon fibers allows the plastic, when heated, to mold and conform to the positive shape. "It's 25 percent stronger than normal propylene," he adds.

Peering into the Future

"I think we'll see more use of smart materials," says Dennis Clark, CPO, founder of Clark & Associates Prosthetics and Orthotics, O&P1, and OPGA, and chief leadership officer of VGM, all headquartered in Waterloo, Iowa. "There are new materials for components—now it's time for new materials around the socket. The socket is the contact point with the patient." Useful prosthetic socket smart materials Clark would like to see include:

·         - Materials that adapt to limb volume changes throughout the day, increasing comfort and socket stability and eliminating the need for adjustments and changing sock plies 

·         - Materials that react to outside temperature changes to keep the residual limb cool and dry

·         - Smart materials that interface with the human body to maintain intimate socket fit throughout the day without gapping

Regarding O&P practitioners, "We manage orthotic and prosthetic care to improve function, health, and quality of life for the patients we serve," Clark says. "Fabricating [a device] is not the end of what we do—patients' limbs change; their health changes—our job is to manage their O&P care." Clark emphasizes practitioners should ask why new materials and componentry are being considered. More important than new materials, per se, are new materials that meet the patient's needs better, he points out. "We need more research to measure the value of new materials to what we provide patients, as well as in general what we provide— which is better outcomes."

Stem Cells: Wave of the Future?

"Stem cells will revolutionize not only just O&P but the medical field in its entirety," says Stephen Hill, BOCO, president and CEO of Delphi Ortho, Asheville, North Carolina. Hill is secretary and founding member of the Orthotic Prosthetic Technological Association (OPTA).

Hill foresees that within 30 years most diseases and conditions will be treated with stem cell therapies, with many current medical specialties no longer being needed. Coupled with "bio ink" (liquid cell suspensions housed in what are basically printing cartridges) and 3D bioprinters, organ stem cells can be lab-grown into a new organ, then printed out on a bioprinter and used to surgically replace a badly damaged, cancerous, or otherwise diseased organ. Regenerative medicine is a lively area of research. Even new limbs may be regenerated in the future, Hill says. Although the use of embryonic stem cells is controversial, adult (somatic) undifferentiated cells show promise in areas generally utilizing embryonic stem cells, which may address some ethical concerns.

Other Future Trends

"There will be a move toward more dynamic socket materials and the ability to provide adjustability," Caldwell says. "Technicians will become even more important members of the clinical support team, including more patient interactions and an increasing role in patient care."

"You're not going to see many technicians in practitioners' shops; you're going to see more central fabs," says Ronnie Graves, CO, LPO, CTP, BOCO, BOCP, owner and president of Veterinary Inclusive Prosthetics/ Orthotics and Prosthetics Research Specialists, Bushnell, Florida. "Practitioners are going to have to rely on the central fab of their choice." Graves thinks one reason is economic—the costliness of maintaining an in-house technical staff. "So, you see central fabs expanding their numbers of technicians and expanding what they expect from each technician."

"The larger central fabrication facilities have been getting more into 3D printing and developing different polymers," says Travis Petersen, BOCP, COA, practitioner and clinic manager at A.O.P. Orthotics and Prosthetics, Fayetteville, North Carolina. "Almost anything can be 3D printed— ceramics, glass, concrete. There's a definite future in prosthetics for 3D printing; it's just not widespread yet." Petersen appreciates the recent elevated vacuum suspension systems, but would like to see more durable suspension sleeves and more reliable pumps. "The more complicated the system is, the more patient compliance goes down. So, I see a trend for manufacturers to simplify what they have. On the other end of the scale, with the current boom in technology, there will be more complicated devices being developed— because they can," he adds.

Socket suspension is also going to be key, Petersen says, whether using a skin-to-socket suspension, a liner interface, a pin lock, or a lanyard. "Osseointegration is going to be a trend; there is a lot of research and excitement centering on it."

In another area, Petersen comments on a technique to impregnate a stiffer resin into the socket lamination, whereby about three-quarters of the way down a more flexible resin is introduced, which creates a stiffer distal socket with a flexible brim.

Keeping on Top of Technology

Education Is Key

Education is the key to staying abreast in a fast-changing world.

"Technicians need good hand skills, but brain skills are going to take a bigger and bigger role in what we do," Hill says. "For instance, back in the day, if you could laminate sockets and bend metal, you were more valuable to your employer. Now, can you operate a CAD program? Do you know how to set up electronic systems?" He adds that he thinks it is important for employers to pay to educate their technicians.

In anticipation of the 2017 World Congress of the American Orthotic & Prosthetic Association, September 6-9 in Las Vegas, Hill says that OPTA is planning "something special" for the technical program it presents every year. "SteamPunk Bionics Academy will present a full-day program covering 3D scanning, CAD design and editing, and 3D printing. Attendees will print out their design and can keep what they create."

In many facilities, technicians are required to simply complete the clinician's work order, without leeway to try new materials or techniques, Clark says. "Many technicians are excited to learn new things and love new challenges and are looking for collaboration with prosthetists." He adds, "Prosthetists need to share education with the technicians. Let's not keep using the same cookie-cutter methods—let's expand the envelope."

"I've always trained my technical staff to experiment," Graves says. "I know the bottom line is critical. But if technical staff isn't given the freedom to experiment, they're going to be afraid to try a new silicone or resin, for instance, because if they blow a socket [fabrication], the boss is going to get mad. But if you give them the freedom to experiment, they can find out how something works, or maybe why it doesn't work. If it doesn't work, ask them, ‘What did you learn from it? What would you do differently?'"

Graves urges technicians to take some courses on materials science to know why certain materials are used, and "not just because the guy before you said this is how it should be done." Technicians need to make the extra effort and take the initiative to add to their knowledge and skillsets, Graves says. In his career, making that extra effort has led to better positions.

He especially remembers one occasion: "Years [ago] when I worked for a central fab in Orlando, Florida, we wanted to laminate our own flexible liners; then Fillauer came up with the 3-S silicone liner. I asked my boss for time off to take Fillauer's course and to pay my expenses to attend. He refused, so I took my vacation time and paid my own expenses to go Chattanooga to take the course." He continues, "About two weeks after getting back, an order came through to make that 3-S silicone liner. The boss asked me, ‘Aren't you trained on this?' I said, ‘Yep.' He said, ‘Good, you can make it for the customer.' I said, ‘Nope.' Then I said, ‘I will, as soon as you reimburse me for my travel expenses and my vacation pay.' And they put it in on my paycheck that week."

Michael Shelburne, CP, operations manager at Össur Orlando Custom Fabrication, says, "For orthotics, I'd like to see materials that are durable but flexible for the comfort of the patient. For prosthetic sockets, I'd like to see much the same: breathability, very lightweight, durable, but flexible enough to be comfortable for the patient." Besides education, adaptability to change is the most important quality for a technician, Shelburne says. "It's an ever-growing industry where things can change very quickly, so in the future, the ability to adapt is the best skillset technicians can have."

Adapting to Change

Curiosity may have killed the cat in the adage, but based on comments from O&P technicians and practitioners, curiosity helps them embrace gaining new knowledge and skills to take advantage of new materials, componentry designs, and fabrication techniques for better patient outcomes. As George Bernard Shaw said, "Progress is impossible without change."

Miki Fairley is a freelance writer based in southwest Colorado. She can be contacted at