Clinical Evaluation of a Voluntary-Closing Terminal Device for Below-Elbow Amputees

ROBIN C. CRANDALL, MD AND DONABELLE HANSEN, RPT


Terminal device function is extremely important in the overall satisfaction of upper-limb amputees. Unilateral amputees, especially those at the below-elbow level, are apt to reject the prosthesis if function is not good or excellent. Most children with upper-limb amputation at the Shriners Hospital for Crippled Children in Minneapolis have been fitted with voluntary-opening body-powered terminal devices, primarily the Dorrance 12P and 10X. Many with below-elbow deficiency also received myoelectric prostheses. In this report, we compare function and responses of a randomized group of children who were fitted with a voluntary-closing, body-powered terminal device. Those using myoelectric units were not included in the study.

Method

Twenty children, including 11 boys, were randomly selected to be provided with the Adept voluntary-closing terminal device . All were long-term patients at the Shriners Hospital. Most received their first prosthesis within the first year, with the average age at initial fitting of 10.5 months. They used prostheses for an average of 8.9 years. Their average age at the start of this study was 9.5 years. A major requirement for inclusion in the study was good prosthetic use, at least 40 hours per week. The entire group, in fact, averaged 80 hours of prosthesis usage weekly. Nineteen participants had congenital below-elbow deficiency, and one had traumatic amputation. Figure 2 .

Patients and their families were shown videotapes of the voluntary-closing device usage prior to fitting. Families were instructed in the action of the device and the repair of minor problems, such as erosion of the elastic components. Training in the use of the new device was conducted by physical therapists and other clinical personnel. Clinical evaluations were made at the time of fitting and at six month intervals. The minimum period of follow-up was one year. Questionnaires were sent to the patients six months after fitting. At the six month visit, they were assessed in the physical therapy department. Children were rated according to their ability to pick, grasp, and manipulate a variety of objects and use the terminal device functionally. Subjects placed different items in a bucket. Functional activities were emphasized, including holding a fork for cutting meat, opening an adhesive bandage, tying shoe laces, holding playing cards, and controlling the prosthesis when throwing a ball and swinging a bat. Testing also involved using age-appropriate toys, such as holding paper while cutting with scissors, stringing beads, and removing tops from plastic bottles. Parents were instructed in harness adjustments at the six month visit.

Results

Sixteen children highly preferred the voluntary-closing terminal device. They all refused to return to the original voluntary-opening hook. A frequent comment was that with the voluntary-closing prosthesis, it was easier to ride a bicycle and hold a bat. Many subjects said that tying shoe laces was easier and most stated that the advantage of lifting heavier objects was substantial. In general, the time needed to learn to operate the Adept device was brief, from 10 minutes to an hour.

Two boys and two girls rejected the new terminal device. They averaged 16.5 years of age. Appearance and adjustment difficulties were cited as problems by some older participants. In contrast, younger wearers claimed the Adept's appearance was an improvement.

Discussion

This study suggests that children with below-elbow amputations who use voluntary-opening terminal devices benefit from early conversion to a voluntary-closing design. For patients who prefer body-powered prostheses, we feel strongly that voluntary-opening hooks offer no significiant advantage. Sensory feedback may be the key factor in the large rate of acceptance of the Adept voluntary-closing terminal device which we observed. Rather than using primarily visual cues, the wearer certainly perceives objects through the harness and by socket pressure. Most patients stated that grasping larger objects and handling heavier items was improved markedly with the voluntary-closing design.

Prosthetic components evolve continuously. Recent advances have made major improvements in prosthetic options. Myoelectric units and voluntary-opening designs, such as the CAPP #2 terminal device,1 augment the choices available to patients and their families. Further controlled clinical trials are needed to improve clinical management. This study has demonstrated that the Adept voluntary-closing terminal device is a useful prescription alternative.

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References:

  1. Shaperman J: The CAPP Terminal Device: A Preliminary Clinical Evaluation. InterClinic Information Bulletin 14:1-12, 1975.