Clinical application study of externally powered upper-limb prosthetics systems: the VA elbow, the VA hand, and the VA/NU myoelectric hand systems.

The results have been presented of a 2-year survey designed to determine whether external power systems offer a significant contribution to the needs of the upper-limb amputee or whether they represent novelties duplicating the functions of conventional mechanical components. The following conclusions have been drawn: 1. External power does offer advantages to the arm amputee. Myoelectric control, especially combined with a self-suspending socket, offers an otherwise normal partial forearm amputee better function without the necessity of a harness. External power, especially for the short partial or total arm amputee and others with limited excursion, brings increased function with less effort. For these patients the advantages of such components as the electric elbow outweigh the recent disadvantages. 2. The components evaluated in this Study are not without limitations. Maintenance requirements of the VA Elbow were excessive. The VA Elbow should not be prescribed for patients who do heavy work with their prostheses because the flexspline may break. Regarding such concerns as lack of sensory feedback, noise, weight, and flexion/extension speed, the advantages of each unit must be weighed against the disadvantages with preference to the individual amputee. 3. The endoskeletal forearm with soft cover is an advantage because of its lightness and cosmesis. 4. Because of the many malfunctions attributed to prosthetist errors, the need is evident for thorough specialized education in the field of external power. A few centralized fabrication facilities may be desirable as opposed to fabrication by many facilities with limited experience. Modular components that are interchangeable and field repairable would be desirable. The systems should be fitted, installed and repaired only by trained prosthetists who have successfully completed a course in externally powered upper-limb prostheses. All members of the Clinic Team should be thoroughly educated in external power as it is related to prosthetics. 5. Many malfunctions were due to patient misuse. Patients, too, after careful selection must be given thorough training in the care and use of externally powered components, including the limitations and capabilities of these devices. 6. Finally, and most important, the Clinic Team must be recognized as the focal point for the selection of patients and prescription of devices. Each patient must be carefully screened for information such as occupation, motivation, prosthesis use (as opposed to wear), ability to learn and follow through with instructions (charging batteries, etc.), and most importantly, the benefits that external power can offer.