Notes From The Prosthetics Research Program

This article continues the series of abstracts from reports issued by prosthetics research laboratories in the United States and Canada. The material which follows was published as part of the Annual Report 1967 of the Child Amputee Prosthetics Project, University of California, Los Angeles. Yoshio Setoguchi, M.D., is medical director and Cameron B. Hall, M.D., is orthopaedic consultant.

Research Activities

During this year of transition, the research work at the Child Amputee Prosthetics Project has continued, although with some delay. Following is a resume of the status of previously reported studies as well as some new research endeavors.

  1. Terminal Device. The new design has been finalized. It will incorporate our principles of: light weight, better cosmesis, improved holding and/or frictional surface and center-pull cable operation. With the grant from the Children's Bureau, we are in the process of having an injection mold made for production of a limited number of models for field testing. Two types will be produced. Both will be the same length as a Dorrance 10X hook but with the opening of a 99X hook. One will be passive and the other will be active.

  2. All-Plastic Wrist Unit. The unit has been re-designed to provide a 360-degree friction contact. This item also is to be produced for field testing.

  3. Unitized Infant Below-Elbow Prosthesis . Three more infants have been fitted with this unit, making a total of nine. The three latest prostheses were fabricated by one of our clinical prosthetists rather than by the designer and revealed some problems in wrap-taking and harness fabrication. Improvement in instructional information corrected these problems. A report for publication covering the problems our clinic has noted with the standard below-elbow prosthesis, our design criteria for the new units, and a description of the components which were designed, together with a preliminary evaluation, has been prepared. If indicated, additional fittings and modifications will be made during the coming year.

  4. Statistical Survey of the Incidence of Limb-Deficient Newborn. This pilot study involved reviewing the records of thirteen hospitals in the northwest area of Los Angeles. The period from 1947 to 1966 was covered and the number of limbdeficient newborn for each year was compared to the total number of live births for each year in each individual hospital. An aggregate of 448,343 live births had occurred during the study years at these hospitals. Pilot study findings were: (a) The frequency of limb-deficient births in Los Angeles was approximately 1:2,000. (b) Neither an increasing nor a decreasing frequency was observed. The paucity of cases in 1952 and 1960 led to many hypotheses of etiology. (c) A marked seasonal distribution of skeletal deficiencies among live births was observed, a finding confirmed by the reports of other investigators. An application for a grant to pursue the study on a larger scale and in greater depth has been submitted. The Child Amputee Prosthetics Project can no longer finance the study.

  5. Electric Cart. This device is now ready for production for field testing. Some minor changes are being made by Mr. Carl Sumida on the frame, seat platform and drive mechanism. The basic principles of easy operation, light weight, and easy maintenance are still being followed. (For more details see 1965 Annual Report.)

  6. Unitized Above-Elbow Unit. This unit is being completely revised. The principle will be the same. It appears now that the elbow joint can also be used as a simple shoulder joint with the motions available passively to include flexion, extension, abduction and adduction. The problem encountered at the moment is the gauntlet for the unit. We are looking for a plastic, cosmetic material that can cover the elbow joint and yet provide elasticity to allow full motion without binding.

  7. Harness Clip. This unit has been produced in small numbers and is being fitted on several of our patients. On upper-extremity amputees it has been used for a bilateral , shoulder-disarticulation prosthesis. The anterior chest strap is attached to the sockets by these clips instead of snaps. The patient is now able to don and remove the prosthesis independently. On lower-extremity amputees the clips are used with the Silesian bandage because snaps needed replacement frequently, and with some of our patients it was as often as once every two months. Except for incorrectly made clips, wear and maintenance have been minimal.

  8. Two-Position Post. No additional work has been done inasmuch as a six-month test period on six children revealed a great many areas requiring improvement and change in design. The idea of a two-position post appealed to all who wore them, but both sizes of openings were too large, the positioning mechanism required frequent repair, the shape and length of projections gave no opposition to the ulnar area making grasp of small objects from a surface difficult. The bracelet design did not provide stability with comfort. Straps were required and frequent adjustments were needed. Since the basic concept of this prosthetic device is desirable, further design and development will be done in the future.