The Helper Arm

Janet G. Marshall, CPO/LPO

A couple of years ago, the father of a patient with congenital absence below the elbow spoke to me about an idea he had. He had been observing his son from birth and had been amazed how adept at compensating for the lack of a hand his son had become. His son had been a prosthetic user since two years of age and was approaching adolescence. Although he often wore his prosthesis, he also could do most activities without. The elbow formed a useful grip by flexing around objects, holding bags, steadying papers, and many other natural uses in daily life. The father suggested that an above elbow amputee would benefit from a "helper arm" that could be an extension from the residuum without the complication of a harness. It would optimally be self suspending, light in weight, easy to don and doff independently, and mostly have functions that could be task oriented that fulfilled the demands of play or some work.

My patient that seemed to meet the criteria for the helper arm was a four year old female that had been wearing a modified above elbow prosthesis since two years of age that she had been fit with at another facility. Since she had out grown it, the parents were anxious for her to receive a traditional above elbow prosthesis with a working elbow for the first time, and a voluntary opening hand. This would require an admission process for the fitting and occupational therapy to assure the opportunity for success. Some of the difficulties she had without wearing a prosthesis were to hold papers down to draw, riding a bike, carrying objects that required a two hand hold, and other tasks. I approached them with the idea of making an additional "helper arm" for playtime that would not require a harness. They were amenable to the project, and even offered a silicone sleeve from a previous arm, which was perfect for the suspension.

Using the base mold from her main prosthesis, I began to build an arm by gluing layer upon layer of one half inch pelite material, shaping it to reflect her sound side dimensions. The natural bend of the elbow at rest was replicated, but not hinged, so that it could comfortably hold objects in opposition. When I was satisfied with the shape and angle, the arm was vacuum formed with thin polypropylene plastic, with a fun decorative pattern. I then pulled a second band that could act a paper holder just proximal to the terminal end attached with screws. Using silicone by first heating it in the oven, I wrapped it around close to distal end and then shaped a gripping type hook for the purpose of holding objects with handles. The terminal end had pelite glued to it and shaped with a groove that could steady the bicycle handlebar, and grip materials when pressed upon. The suspension was the silicone sleeve with the use of a Velcro strap attached distally that threaded easily through a hole in the plastic arm, and adhered to the outside of the arm. During the admission, the young patient learned quickly to proficiently use the traditional prosthesis. She could flex the elbow, position the arm to retrieve and place objects with the terminal device, and started using the arm for daily activities. The helper arm, likewise was used in the admission for assisting in artwork, riding the bike and carrying handled bags. The patient and the family left with the satisfaction of having both arms to try for school and play. Several months later, they returned to the hospital for a minor revision of an overgrowth. I took the opportunity to discuss with the mother the wearing habits that prevailed with the prostheses. The patient preferred to wear the traditional arm to school or nothing at all. When at home, she would wear both arms for different activities. She played in the helper arm, especially if she wanted to carry objects. However, she was most comfortable not wearing either arm, which surprised the parent. In discussing this further, she wondered if the school environment was creating a situation that discouraged her, possibly due to other children questioning why she wore a prosthesis. The mother was currently content with letting time take its course, and remain an encouraging parent.

Wearing a prosthesis is a choice that cannot be forced upon the individual. Exploring new designs to give options for wear, and keeping a focus on task orientation and function can make a difference in acceptance. This prototype for an above elbow amputee has been relatively well received, giving the initiative to keep experimenting with other patients to try and improve on the design. Different functional tools could be interchanged if a wrist unit was added to the unit that would establish more of a work oriented device. If this avenue can be successful, then the byproduct of easing the load of dependence on the sound side can be achieved by furnishing additional options in the "helper arm".

Shriners Hospital for Children Tampa, Florida