Notes From The Prosthetics Research Program

This is the second in a series of abstracts from reports issued by prosthetics research laboratories in the United States and Canada. The material which follows is a portion of the activity report for April-June 1967 from the Northwestern University Prosthetic Research Center (Edward C. Grahn, Project Director).


Upper-Extremity Program

  1. Electric Power Assist. The power unit has been adapted to the hand splint of a quadriplegic (C5 and C6 involvement). Trial use of the device showed good function of the splint.

  2. Ball and Socket Shoulder Joint. Four friction materials have been tested, with disappointing results thus far. The material was presented as having equal static and dynamic coefficients of friction; however, there was a noticeable change when going from static to dynamic conditions. Two materials remain to be tested.

  3. Powered Wrist Rotator. The first prototype has been constructed and will be fitted to an amputee. The unit weighs 9 ounces and is to be laminated to the end of a forearm in a manner similar to a standard wrist unit.

  4. Motor Speed Control and EMG Signal Processing. Development of devices for the control of external power from myoelectric signals has continued.

Lower-Extremity Program

  1. Above-Knee Pneumatic Sockets. One amputee continues to successfully wear the above-knee socket with the inflatable bag placed in the lateral wall.

  2. Below-Knee Sockets. Three amputees have been fitted with patellar-tendon-supracondylar prostheses, with a different suspension technique being used with each. Thermoplastic polymer rubber material is being tested as a means of direct forming of below-knee sockets. Two methods are under investigation: (1) direct forming against the stump, and (2) direct forming against a model of the stump. The thermoplastic material requires reinforcement. Direct application of polyester resin to the thermoplastic material on the stump caused no skin irritation, but discomfort from the fumes was elicited.

  3. Immediate Postsurgical Fittings. Ten immediate postsurgical fittings were carried out, including four above-knee, five below-knee, and one Syme's amputation.

  4. Polycentric Knee. There is no further progress to report from this quarter.