A Device for Every Season… or Every Activity

TRS Swinger terminal device

This is an example of a custom silicone socket that has no rigid lamination. The TRS Swinger terminal device used here was designed for hanging, but also works well for swinging a bat. Photograph courtesy of Handspring.

TAD hand cultivator terminal device

This activity-specific prosthesis is simple, yet versatile. Anatomical contouring prevents rotation and a multiflexion quick disconnect wrist unit from Texas Assistive Devices (TAD) allows for attachment of a variety of different tools depending on the desired task. Here a TAD hand cultivator terminal device for gardening is used. Photograph courtesy of Handspring.

A man utilizes a pruning saw with his myoelectric prosthesis

A man utilizes a pruning saw with his myoelectric prosthesis. Photograph courtesy of Texas Assistive Devices (TAD).

For many individuals with upper-limb amputations or upper-limb differences, being able to participate in all the activities that lead to a full life requires more than one prosthesis or terminal device. For some, this may mean using a cosmetic hand for some occasions and a hook for others, or using a myoelectric prosthesis for everyday and social situations but a body-powered prosthesis for heavier, more rigorous tasks. Individuals may need activity-specific prostheses or terminal devices to allow them to pursue favorite sports and hobbies such as golfing, fishing, kayaking, bicycling, gardening, or playing a guitar. The right prosthesis helps people with limb loss to be independent, return to work after a traumatic injury, enjoy social activities, and perform the myriad tasks involved in homemaking and family care.

Six Prosthetic Options

There are six basic prosthetic options, says John M. Miguelez, CP, FAAOP(D), president and clinical director of Advanced Arm Dynamics (AAD), headquartered in Redondo Beach, California: no prosthesis, passive cosmetic restoration, body-powered prosthesis, electrically powered prosthesis, hybrid prosthesis, and activity-specific prosthesis.

"Since our hands and arms have amazing functionality and complexity, it is unrealistic to believe an individual with an upper-limb amputation can do everything with a single prosthesis," says Randall Alley, BSc, CP/L, CEO, biodesigns, Westlake Village, California. "Our challenge is convincing insurance companies, when appropriate, [that] upper-limb patients should have more than one option. In many cases, patients can benefit from an electrically powered system with a multiarticulated hand, plus a body-powered system and an adaptive system," he adds. "Many of our patients are extremely active and are able to return to work and assume normal activities with the proper prosthetic systems. For example, we have several patients who use their i-limb for everyday use and their body-powered [prosthesis] with an electric hook specifically to work with machinery. It is our job to justify how and why they need them."

biodesigns HiFi Interface prosthesis

A motorcyclist utilizes a biodesigns HiFi Interface prosthesis with a Mert Lawwill motorcycle/bicycle terminal device. Photograph courtesy of biodesigns.

Criterium handlebar adapter

A cyclist uses the Criterium handlebar adapter during a race. Photograph courtesy of TRS Prosthetics.

boy on bicycle with TRS adapter

A boy displays how an adapter designed for bicycles can be used for other activities, such as with his scooter. Photograph courtesy of TRS Prosthetics.

Max Okun on pull-up bar

Okun's prosthesis stays locked on even when hanging from a pull-up bar for twisting knee tucks. Photograph courtesy of Advanced Arm Dynamics.

Sydney Howard uses the Swinger terminal device for gymnastics

Sydney Howard uses the Swinger terminal device to pursue her gymnastics passion. Photograph courtesy of TRS Prosthetics.


Multiarticulating Hands

The outlook for high-tech upper-limb prostheses is getting brighter and brighter as advances continue in function, control systems, proprioception, sense of touch, and appearance. For example, three commercially available multiarticulating prosthetic hands provide function that is much closer to natural hand function than ever before, along with a sophisticated, stylish, anthropomorphic appearance. The bebionic hand from Steeper, Leeds, England; the i-limb from Touch Bionics, Livingston, Scotland; and the Michelangelo hand from Ottobock, Duderstadt, Germany, offer a variety of options, including some for partial-hand and finger amputations.

Body Power

"A tech competition in Zurich showed that body-powered technology outperformed some of the most expensive technologies in the world," says Robert "Bob" Radocy, president and CEO of TRS Prosthetics, Boulder, Colorado, referring to the first Cybathlon, held on October 8, 2016, in Zurich, Switzerland. Using TRS' new Grip 5 Evolution Prehensor and Sure-Lok cable system, Radocy, a proponent of body-powered prosthetic technology, "breezed through the course in the preliminaries and the finals, earning two perfect scores to win gold for his team," according to an online news story in Scientific American. In the prosthetic arm event, Radocy and his competitors raced against the clock and each other to complete a series of six tasks ranging from picking up different shaped objects on a table to preparing breakfast (including cutting a loaf of bread and using a can opener) to hanging clothes using hangers and clothespins.

Newer socket and suspension technologies are minimizing or eliminating the need for harness and cable systems for many people with upper-limb amputations, which makes using a body-powered prosthesis easier and more comfortable and allows for greater range of motion (ROM). For instance, at Handspring, based in Middletown, New York, prosthetists use anatomical contouring, a liner with a pin lock, or a one-way expulsion valve for suction, or a combination of these technologies to suspend activity-specific prostheses, depending on the activity, says Chris Baschuk, MPO, CPO, LP, an upper-limb specialist at the clinic. A general-purpose body-powered or externally powered prosthesis is meant to function in a wide variety of situations and may incorporate cables to position joints and open and close the terminal device, he explains. However, since most activity-specific prostheses are fabricated for tasks that don't require a voluntary close/ voluntary open terminal device and many don't require cable-driven joint articulations, they typically will not have cabling, he notes.

A well-fitting socket is crucial, Baschuk stresses. A socket for an activity-specific prosthesis may have very different construction and trim lines than a general-purpose prosthetic socket. For example, the entire socket may be made of silicone for increased comfort and flexibility or it may have significant cutouts and areas of high compression for increased control. At times, the prosthesis may become more of a "prosthosis." "The function dictates the form," Baschuk says.

Click Medical's RevoFit™, used at AAD, is a new-generation technology solution that uses strategically placed custom panels and the Boa® Closure System to enable prosthetists to fabricate adjustable prosthetic sockets. The custom panels are placed on areas of the residual limb that fluctuate in volume while leaving more sensitive areas undisturbed. Once integrated, the socket fit can be instantly customized with micro-adjustments of the Boa reel, creating compression, suspension, and closure around the limb, according to Click Medical's website.

Max Okun is a nutritionist, online health coach, and bodybuilder. Due to a congenital left transhumeral limb difference, he sustained a bulging disk in his back from overuse of his sound limb and uneven body mechanics during his workouts. Okun sought prosthetic intervention at AAD. Rob Dodson, CPO, FAAOP, and Julian Wells, CPO, FAAOP, created a prosthesis tough enough to withstand Okun's rigorous workout program. The carbon fiber prosthesis incorporates a pin-lock suspension coupled with a high-strength adjustable lace system, allowing full range of motion; a strong customized elbow using Hosmer/ Fillauer LLC heavy-duty outside locking hinges; a two-way locking wrist invented by an AAD patient, Matt Razink; and interchangeable terminal devices. Although Okun generally prefers not to use a prosthesis, he doesn't go to the gym without this one.

Terminal Devices: Enabling an Active Lifestyle

Although not the only creators of activity-specific terminal devices, Texas Assistive Devices (TAD), Brazoria, Texas, and TRS offer a wide spectrum made for sports, recreation, hobbies, job, and home activities. Although there is some crossover, both companies produce terminal devices and related hardware that are complementary to the focus of the other. "I think of Texas Assistive Devices, in general, as being more tool- and home-oriented while Bob [Radocy] is an outdoor and recreation enthusiast, so his terminal devices are aimed more at sports or other recreational activities," Alley says.

A TAD specialty device is used to hold a nail

A specialty device is used to hold a nail. Photograph courtesy of TAD.

Texas Assistive Devices

"The patented N-Abler II™ Flexion-Rotation Wrist Unit is the versatile heart of TAD's system," explains Ron Farquharson, the company's president and founder. The N-Abler II has a quick insert/disconnect on the distal end that allows the user to easily switch to any of TAD's specially adapted tools, utensils, and implements. The company also offers a Myo-Electric Wrist Adapter.

Farquharson, who has a transradial amputation, uses his company's devices regularly. "The most popular items have always been the ones that give users independence to perform basic activities of daily living without help from others, such as dining utensils, food preparation tools, and personal grooming implements," he says. "After basic daily living items, tools-including mechanics and carpentry tools-are in the most demand." On the recreation side, TAD's Weight Lifting Device is popular among the company's customers, according to Farquharson.

The N-Abler III™ WHO Soft Brace with a Quick Disconnect Palmer Unit can be used by people with hand dysfunctions, partial hand amputations, and spinal injuries, which also gives them access to TAD's prosthetic terminal devices.

"We always try to adapt any items that practitioners or patients ask for," Farquharson says. "Sometimes we recognize that there would be a wider market for certain custom-built items, so they are added to the catalog's regular stock items." For example, he says soldiers with amputations at Walter Reed National Military Medical Center (WRNMMC), Bethesda, Maryland, requested the Heavy Duty Passive Hook, and the N-Abler III WHO Soft Brace was inspired by a suggestion from a group of occupational therapists attending a trade show where TAD was exhibiting.

the TRS Prosthetics Hoopster

The Hoopster, which allows the user to dribble and shoot basketballs, is among many sports-specific terminal devices available. Photograph courtesy of TRS Prosthetics.


Radocy is seeing increasing interest in his company's activity-specific prosthetic devices. "The kayaking and canoeing device and weight lifting and fitness training prosthetic devices have been very popular," he says. "I'm also seeing more of what we call crossover technologies-consumers are sending us photos and videos and saying, 'See what I did with this device.' Our devices are being used for activities that they're not necessarily designed for, but are filling a consumer's need."

Radocy offers two examples of these crossover activities. TRS' Criterium bicycle handlebar adapters have also been used for such activities as pushing shopping carts or baby strollers. Another example is the company's Shroom Tumbler, a high-performance, polyurethane device that resembles a mushroom. Originally made for tumbling, yoga, and other mat activities, they have also been purchased by WRNMMC so patients could use them to push wheelchairs rather than using their expensive myoelectric hands. "It's unique in that [it] flexes in all directions and thus has no unique directionality, so users can do front flips, backflips, etc.," he says.

A recent development from TRS is the voluntary closing Grip 5 Evolution Prehensor that Radocy used in the Cybathlon competition. "It was five years in development and is the most complicated, expensive device we've ever made," he says. "It gives really good control over objects, with greater stability, and is a reliable alternative to biomechanical hands." The prehensor is lightweight, is constructed of 7075 AL T6 aircraft aluminum with a stainless-steel core, and has directly proportional gripping control and user-controlled biofeedback.

Living Life Fully Requires More Than a Prosthesis

For individuals with upper-limb amputations or upper-limb differences, living life fully requires more than a "wardrobe" of prostheses to meet life's various joys and demands. Many upper-limb specialists consider occupational therapy to be integral to prosthetic success, as is maintaining a healthy lifestyle and a positive outlook.

the TRS Prosthetics Eagle Flex terminal device

A silicone liner with a pin lock is used to create a prosthesis with lower than normal trim lines for golfing. The lower trim lines allow for unrestricted elbow flexion. A TRS Eagle Flex terminal device is used to secure the club. Photograph courtesy of Handspring.

Companies that specialize in upper-limb prostheses generally have strong working relationships with occupational therapists (OTs) experienced in working with this patient population. "The advantage of this experience and training to the patient and the clinical team is that we are very up-to-date with the latest treatment interventions and technologies, plus we are very experienced in treatment of the various amputation levels and the technologies that go along with it," says AAD National Director of Therapeutic Services Tiffany Ryan, MOT, OTR/L. She adds, "We help patients through our experience and knowledge, which is being continually updated, so the learning curve is shortened for our patients." AAD employs full-time OTs at each Center of Excellence, so OTs are available to assist patients through all the stages of amputation care, from acute through pre-prosthetic, interim, and post-prosthetic care.

Insights in Initial Evaluations

AAD clinicians use a holistic approach in their initial evaluations of new patients and include a prosthetist and an OT, Miguelez explains. In addition to the typical evaluation that includes such things as assessing the condition of the residual limb, ROM, and the patient's overall physical condition, and getting to know the patient and his or her goals and lifestyle, the team also asks the patient to complete a psychological assessment called the Wellness Inventory, Miguelez adds. The Wellness Inventory is a battery of seven validated screening instruments that measure resilience, health-related quality of life, pain, depression, alcohol use, drug use/misuse, and post-traumatic anxiety ("Mental Health Screening in Upper Limb Outpatient Prosthetics Clinics: Identifying Challenges to Prosthetic Rehabilitation Success," Journal of Proceedings, March 2015, American Academy of Orthotists and Prosthetists). Depending on the results, the clinical team may refer the patient to a psychologist, psychiatrist, or social worker.

Alley also stresses a holistic approach to patient evaluation. He mentions that in the initial patient evaluation, "We pay a lot more attention, not only to their goals and desires, of course, but also to their preconceived notions and past experiences. These play a much wider role than many prosthetists realize. I think it's incredibly important to know how they perceive what they want and once they get it, how they ultimately will succeed with it."

Max Okun working out on battle ropes

Okun's prosthesis allows him to do an intense arm workout with alternating waves of battle ropes. Photograph courtesy of Advanced Arm Dynamics.

Alley says that many of his patients are already motivated to increase their performance and accomplish active-lifestyle goals, traveling to biodesigns because of interest in the company's High-Fidelity Interface™, which stabilizes and controls the wearer's underlying bone with patented and patents-pending compression and tissue release technology. "It is critical, no matter how small or large the goal, that we are there to give them the ability to accomplish what they set out to do. Our challenges vary-one day we are giving a patient the ability to swim again, the next day we are working with a soldier to prepare him for Green Beret training. One is not more or less important than the other. The key is building up their confidence. But we can't do it alone. The doctor, the physical therapist, the occupational therapist, the psychologist/ psychiatrist (in some cases), and the patient all are part of the team."

Alley emphasizes the need for patients to take it slow. "Probably the thing my patients do the most is to wear their prosthesis far too long the first day/first week, despite what I tell them about taking it easy and breaking it in. They are not used to having a socket that feels connected to them, a part of them, so they usually want to continue wearing it."

A thorough initial evaluation that goes beyond ROM and residual limb condition is also important in terms of helping with reimbursement concerns so the patient can receive activity-specific prostheses. "It can be challenging to be reimbursed for an activity-specific prosthesis, but with the right approach it is possible," Baschuk says. "Upper-limb loss results in multiple functional deficits that cannot be addressed by a single prosthesis. The rehabilitation team needs to be made aware of this so that they can effectively articulate this in their documentation to the payers. When the physician, occupational and physical therapists, and the prosthetist develop the treatment plan, the focus should be on the health benefits and overall impact on the patient's quality of life, both physically and psychologically, rather than just stating, 'This is something the patient really likes to do.'"

Reimbursement specialists note that submitting clean claims, knowing appeals procedures, having good relationships with payers, and being persistent help greatly, along with obtaining adequate physician documentation.

One prosthesis can't do it all for people with amputations who want to realize their potential and ability to be productive, be healthy, and experience life to the fullest. When it's obtainable, a prosthetic "wardrobe" is not a luxury, but a necessity.

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