Technical Note: Adaptor for Aligning
the Quantum Foot to an Exoskeletal
Prosthesis
William D. Hamby, R.A.O.
Richard A. Broom, G.P.O.
Stephen Olejnik, Ph.D.
Introduction
Recent developments in lower extremity
prosthetics have resulted in an increased
number of options available to the amputee.
These new products generally offer greater
comfort and allow increased mobility to athletic amputees. Michael (1) recently summarized many of these new developments. After reviewing several of these alternatives,
one of our patients chose the Quantum foot
(2) and asked that it be attached to his exoskeletal prosthesis. When we attempted to
meet the client's request, it quickly became
apparent that this could not be done successfully using the horizontal transfer machine.
We contacted Hosmer Dorrance Corporation and explained the problem. They responded by suggesting the ultra-Roelite system and we agreed to try it. After examining
this alignment tool, it was clear that the system was designed for an endoskeletal prosthesis and provided for angular changes
only. Nevertheless, we could have used our
horizontal transfer machine if we would have
been satisfied with a less than optimal alignment. We were not.
When aligning other foot prostheses with
exoskeletal prostheses we use the BKL100
which allows for both angular and linear
changes. Unfortunately, because of the ankle plate used in the Quantum foot, there did
not appear to be any way to attach it to the
BKL100 in our transfer machine. One solution would have been to purchase a vertical
fabrication machine. Such a purchase could
not be justified, however, based on what
we anticipated would be its limited future
use.
Adaptor Design
Our solution was to design a new adaptor
for the BKL100 which would permit attaching it to the Quantum foot. A picture of the
final product is presented in Figure 1
. The
sequence of attachments is presented in Figure 2
and Figure 3
. The adaptor is constructed of aluminum, is 3 inches long, has a 1 1/4inch diameter where it attaches to the
BKL100 and has a 2-inch diameter where it
attaches to the Quantum foot. It is held in
the BKL100 using a hose clamp on the pylon. To attach the adaptor to the Quantum
foot, we used a 1/2-inch cross shaped lip and
four machine screws.
Conclusion
This adaptor has been used on several occasions for aligning the Quantum foot with
the BKLIOO. Each time it has worked without difficulty. The adaptor is a simple solution to an important problem. The Quantum
foot has several important advantages over
alternative prosthetic feet, including its
spring module, its attractive cosmesis and its
almost natural action. In addition, it is lightweight. The exoskeletal prosthesis has the
advantage of durability, and because the
BKL100 is used for alignment, both linear
and angular changes can be made. The adaptor described makes it possible to use both
systems at a minimum cost.
William D. Hamby, R.A.O., is a registered
assistant in orthotics at Roosevelt Warm Springs
Institute for Rehabilitation, P.O. Box 1000,
Warm Springs, Ga. 31830.
Richard A. Broom, C.P.O., is a certified prosthetist-orthotist at Roosevelt Warm Springs institute for Rehabilitation, P.O. Box 1000, Warm
Springs, Ga. 31830.
Stephen Olejnik, Ph.D., is a research consultant to Roosevelt Warm Springs Institute for Rehabilitation and professor of Educational Psychology at the University of Georgia, 329 Aderhold Hall, Athens, Ga. 30602.
References:
- Michael JW. New developments in prosthetic feet for sports and recreation. PALAESTRA:
The Forum of Sport, Physical Education and Recreation for the Disabled, 1989; (5)2:21-31.
- The Quantum foot is manufactured by
Hosmer Dorrance Corp.
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