Let's Put a Hand on Captain Hook

Elaine Trefler, P. & O.T. Reg., BOT


How many occupational therapists have been asked by the mother of a child amputee-will the thing at the end of the prosthesis look like a hand? Does it have fingers? And how many therapists have in frustration answered, "No, it will be shaped like a hook because that kind of device works better than an artificial hand."

For years we have accepted as obvious the advantages of the hook terminal device. It is light, durable, easy to operate, offers fine pinch prehension and is readily available from commercial sources. Also, the disadvantages of the available mechanical hands have been painfully evident:

  • They are too large for children below the ages of five to seven years.

  • They are very heavy and are often difficult to operate.

  • The cosmetic gloves are being quickly torn or discoloured by an active child amputee.

Although the available hands do offer a pinch of the three-jaw-chuck type, the child who has worn a hook for several years finds the hand heavy to wear and awkward to position. Therefore, their first hand, often anxiously awaited, is usually a disappointment and is rarely used functionally.

In society our views are changing. We are acknowledging that hooks are not esthetically pleasing. We are now listening more attentively to the comments of parents about their child's prosthesis because we know that if the parent accepts the prosthesis in all likelihood the child will also. We are listening to the complaints of the child who is being called Captain Hook and does not want to return to school.

In the author's view professional personnel working with the juvenile amputee should take a closer look at the terminal devices available for the amputee, from his first fitting at six months of age on through the total range of his needs as he grows from infancy to adulthood.

The Dorrance passive mitt and 12-P and 10-X hook terminal devices are familiar to all individuals who work with the juvenile amputee. The mitt attempts to provide some cosmesis in the child's first terminal device and generally is accepted better by the parents than is the 12-P hook. However, it still doesn't resemble a hand.

Other attempts to provide cosmesis and function have been the University of California, Los Angeles (UCLA) center-pull hook6 (Fig. 1 ), the Ontario Crippled Children's Centre three-fingered hook2 (Fig. 2 ), the Otto Bock child-size mechanical hand (Fig. 3 ), and the Dorrance #1 mechanical hand1 (Fig. 4 ).

In training children to use the #1 Dorrance hand several problems have become evident:

  • It is too heavy in relation to the strength and tolerance of the child.

  • The opening is not large enough to accommodate many of the toys a young child wants to handle.

  • When both springs are in place, considerable force must be applied to open the hand. Yet, if one spring is removed to facilitate opening, the pinch force is decreased and objects begin to slip.

The infant passive hand3,4, developed at the Ontario Crippled Children's Centre by Mr. William F. Sauter (Fig. 5 and Fig. 6 ), is an excellent initial step in a program to develop hands for children. This hand is made of polyurethane and is shaped like an infant's hand. The thumb offers a passive lateral pinch to the index finger. Moreover, the fingers are slightly hook-shaped and can be hooked onto a crib side to help the child pull himself up into a standing position. However, these hands are not yet commercially available. An experimental foam-rubber moulding over a standard hook and a child-size functional hand are also being developed by Mr. Sauter, but neither is commercially available at this time.

In spite of these encouraging efforts, a large population of juvenile amputees, especially those with unilateral amputations, is still without mechanical components which are both acceptable and readily available. A prime purpose of this report is to suggest that a new series of functional hands for children be made available.

In the Table which follows some suggestions concerning basic design criteria are presented. These criteria relate to the functional hand requirements of children in four very general age categories. First, there is the infant, who requires a cosmetically acceptable but nonactivated hand. Second, there is the preschool child. At 15 months of age, he is generally able to begin learning the body movements necessary to operate an activated terminal device5. His needs remain fairly constant until he enters school at about the age of 5 years. Third, there is the elementary school child between the ages of about 5 to 11 years. Finally, there is the adolescent who is in high school and beginning to develop specialty skills and interests. Each group has different functional and cosmetic requirements with respect to their terminal devices.

Conclusions

The unilateral amputee uses his subdominant hand primarily for holding purposes. It should be possible to have a well-designed mechanical hand which could meet functional requirements and still be light and durable. New materials now available should permit the design of a functional hand with a life-like appearance and feel that would be greeted with enthusiasm by mother and child. Even if we fail to reach these objectives we should at least Offer the child and his parents a choice between a hook or a hand at all age levels.

Consultant Physical/Occupational Therapist The Winnipeg School Division No. I Winnipeg, Manitoba, Canada

References:
Fishman, S., and H. W. Kay, Acceptability of a functional-cosmetic artificial hand for young children. Child Prosthetic Studies, New York University, New York, 90 pp., January 1964.
McLaurin, C. A., and B. Devitt, The coordinated electric arm. Inter-Clin. Inform. Bull., 8:7:14-15, April 1969.
Ontario Crippled Children's Centre, Prosthetic Research Unit, Annual Report, Toronto, Ontario, Canada, November 1969.
Ontario Crippled Children's Centre, Prosthetic Research Unit, Research Report, Toronto, Ontario, Canada, p. 1, 1970.
Trefler, E., Terminal device activation for infant amputees. Inter-Clin. Inform. Bull., 9:9:11,14, June 1970.
University of California at Los Angeles, Child Amputee Prosthetics Project, Tenth Annual Report, p. 11, 1964.