Adaptive Prosthetics
Upper Extremity Terminal Devices
and Other Components
The term “adaptive prosthetics” can describe many different sorts of devices. In some activities like running or rock climbing, an adaptive prosthesis is a completely separate arm or leg that is used exclusively for that activity. For other activities, people can wear their regular prosthetic arm or leg but change out a single component like the foot or hand. Energy storing feet, snow skiing outriggers, and voluntary-closing prehensors are just a few examples of popular adaptive components. In upper extremity prosthetics there are adaptive terminal devices for everything from playing tennis to lifting weights. The introduction of on-board microprocessors to both upper and lower extremity components is another major advancement.
Sometimes people have their own ideas for an adaptive modification to their prosthesis that will meet their unique need. For example Aron Ralston, a mountaineer and rock climber who is also an upper extremity amputee, has worked with prosthetists on adaptive designs for mountaineering. Since losing his arm in a 2003 rock climbing accident, Aron has become the first person to solo climb all 59 of Colorado’s 14,000-foot peaks during the winter. He has also reached the summit of 23,000-foot Mount Aconcagua in Argentina, South America’s highest mountain.
There are many prosthetic users that channel their competitive energy into sports. From elite competitors to young, aspiring athletes, Hanger patients have excelled in a myriad of athletic endeavors including national and international competitions and the Paralympic Games. Others have achieved success and personal records at running tracks, basketball courts, golf courses and swimming pools around the world. Visit www.hanger.com to read about and be inspired by the stories of individual patient accomplishments.
It is through the ever-expanding world of new prosthetic technologies that people are able to be active participants in life and to enjoy a renewed sense of self-confidence. Relatively few activities are completely “off limits” to the person who combines intense personal motivation with cutting-edge prosthetic technology.
A terminal device is the portion of an upper extremity prosthesis that acts as a hand. Terminal devices provide most of the function of the prosthesis and can be disconnected at the wrist to allow the user to switch to a different device.
Terminal devices are operated by either a body-powered prosthesis or an externally powered prosthesis. The passive hand is a device that does not open or close, but does restore a cosmetically pleasing appearance. Other hands open and close by way of the body-powered harness system.
Electric hands, Grippers and Hooks
Electric hands are probably the most popular as they allow the user to grasp items and also have a reasonably natural appearance. The most advanced of these incorporates sensors in the fingers and hand so that grip strength can adjust automatically.
People who work with their hands often prefer grippers and hooks. Again, these devices can be either body-powered or externally-powered. Grippers and hooks can lift heavier items, have a variable grasp pattern, and are better for picking up and holding smaller objects like a screwdriver or key. Some models can even be used in wet environments.
There are many adaptive accessories that make it easier to hold everything from steering wheels to golf clubs, pool cues to fishing poles.
Hands, grippers, hooks and adaptive accessories each have advantages and disadvantages. Ideally, upper extremity users will be best served with a quick disconnect wrist unit that allows them to switch between various devices.
Depending on your level of amputation, other components that will be important are wrist units, elbow units and shoulder units. Your UEPP (Upper Extremity Prosthetics Program) prosthetist will guide you in making the right choices that will improve your function and independence.