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The Pros and Cons of Computerized Foot Orthotic Technology
By Miki Fairley We tend to take our feet for granted--until problems
develop!
 Although many people believe that each foot only
takes half your body weight during walking, actually walking
creates forces through the feet of about one to two times body
weight. And in an average day, people may take as many as 10,000
steps or more. During running, it is estimated that these forces
can increase to an amazing nine times body weight. Thus, any
inefficiency in foot function is multiplied many times
over--causing many foot and lower limb problems, points out the
podiatric practice of Dunning and Trinder in the United
Kingdom.
Sometimes an orthosis is all that is needed for successful
treatment, but often the orthosis is prescribed along with other
therapies, such as stretching or strengthening exercise, oral or
injectable medications, and specific types of shoes to provide the
fastest healing, explains Kevin A. Kirby, DPM, MS, editor of the
website PodiatryNetwork.com. Kirby lists the advantages of custom
prescription foot orthoses, which include 1) since they fit so
exactly to the foot, they can be made with relatively rigid,
durable materials with a minimal chance of discomfort or
irritation; and 2) they have a much greater potential to
effectively and permanently treat painful conditions, all the way
from the toes to the lower back, since they are designed
specifically for an individual's biomechanical nature. (Note: the
terms "foot orthoses" and "foot orthotics" are used interchangeably
in this article, since the orthotic and pedorthic professionals
quoted used both terms.)
The only disadvantage Kirby sees is cost as compared to
over-the-counter foot inserts. However, he points out a
disadvantage of the OTC orthotics. "Even though the OTC inserts do
help some people with symptoms, they do not have the potential to
correct the wide range of symptoms that prescription foot orthoses
can, since they are made to fit a person with an average' foot
shape." He compares them to prescription eyeglasses: OTC glasses
may work for some people, since they are made to correct the
average' eye; however, they will never work as well as prescription
glasses. "Prescription foot orthoses, since they are custom-made to
each foot of a patient, are almost always more corrective and
comfortable than OTC foot inserts, even though OTC inserts do work
for some people."
 Despite their value to patients, providing custom
foot orthotics is not one of the higher generators of revenue. So
the question arises, how to make them more efficiently and
cost-effectively?
One partial answer at least has proved to be automated foot
orthotic technology. Orthotists, pedorthists, and other healthcare
professionals have found that the technology provides accurate
measurements for fabrication at a big savings in time and labor.
However, even some of the happiest users of the technology still
use other measuring and casting methods for certain patients'
needs.
Versatility, Digital Record, Cost Savings
For instance, Jim Rogers, CPO, FAAOP, Orthotic & Prosthetic
Associates Inc., Chattanooga, Tennessee, is an enthusiastic
proponent of the Amfit system, produced by Amfit Inc., Vancouver,
Washington. Rogers was introduced to the Amfit system about ten
years ago. "The system did a couple of great things," says Rogers.
"It was repeatable--and at that time about the only repeatable
system out there was E-Med. It was very expensive and primarily
diagnostic--not really designed for fabricating an orthosis."
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Courtesy of Amfit |
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Being repeatable means that the system provides an
exact digital record, so a cast doesn't have to be saved in case
the patient later wants another orthotic. "You can push a button,
remake another orthotic at a fraction of the cost of the first one,
and pass that savings on to the patient, which we do," says Rogers.
With repeatable measurements and a digital record, a scan can be
compared with an earlier one, which is helpful for assessing
changes in the foot, especially with progressive conditions such as
diabetes, multiple sclerosis, or arthritis, he adds.
Rogers especially likes the option of being able to print out
the scan: "It's a great marketing and educational tool." The
practitioner also has the option of scanning with weight bearing,
semi weight bearing, or non weight bearing, he noted.
The Amfit program evolved over the years, Rogers said. "What I
really like is the ability to manipulate the image--to modify the
positive mold digitally and send it to a remote carver."
One challenge for practitioners is transferring their mindsets
and skills from being tactile to being able to quantify. "What we
do in orthotics and prosthetics is so tactile," Rogers says. "If
you ask someone how much build-up is needed, they'll show you with
their fingers: about this much,' but if you ask them to quantify
it, they often have trouble doing it." However, once users make
this transition, the orthosis can be modified right on the screen
and carved in eight minutes, Rogers says, adding that users have
five choices of density: soft, medium, two versions of dual
density, which is a combination of soft and rigid, "so you can
impart structural control where you need it," and totally
rigid.
Recent developments in the Amfit machine provide more
versatility, according to Rogers. "Traditionally, you were carving
out the orthotic from the negative with a single material, EVA, but
now you can carve it from EVA or cork. Also, instead of the
orthotic, you can insert an EVA block, a cork block, or a foam
block for a positive mold from which you can fabricate a device
with any material, not just EVA. It can be carbon fiber,
polypropylene, TPE--any number of materials."
Rogers continues, "So what started out as a way to fabricate a
relatively soft EVA orthosis has evolved into a system to get an
excellent scan of the foot, modify it very conveniently, then
decide what material you want for the orthosis and fabricate it."
He also praises Amfit's training: "Amfit really tries to educate
the practitioner on how to use the machine and get the most out of
it."
However, Rogers points out that he doesn't use the machine 100
percent of the time. Orthoses that need to go beyond the margins of
the plantar or dorsal surfaces need to be cast; plus sometimes the
patient's condition makes traditional casting and fabricating the
methods of choice. And, "sometimes it's even appropriate for me to
use an off-the-shelf orthosis," he adds.
Chuck Greene, CPed, University of Michigan Orthotics and
Prosthetics Center, Ann Arbor, also comments that, among other
methods, the center has two Amfit systems that are used a great
deal.
System Garners Pedorthist's Kudos
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Versatile technology has many uses. Courtesy of Tekscan |
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Rick Sevier, CPed, RPOA, RFO, National Foot
Specialties, Tulsa, Oklahoma, happily uses the 3DO system
manufactured by the Quasar Group, Digital Orthotics, Tustin Ranch,
California. The totally portable system includes a laptop computer,
preloaded with the Digital Orthotic software, and a digital sensor
pad, explains Sevier. "The software has some nifty features and
seems very intuitive," he adds. "Just we as practitioners gather
personal data, do an assessment, and then decide which orthotic
design best fits the needs, this software does the same."
Data such as name, age, height, weight, and physical measurement
of the feet is gathered, he explains. Next, a static scan is taken,
which can be viewed in either 2-D or 3-D. Then, a dynamic scan is
taken, in which the patient walks across the pad left foot first,
then right. Sevier notes, "I have found that building a pad from
gym foam' squares (available from any home improvement store) that
brings the ground elevation up to that of the pad gives me much
more reliable results during the dynamic scan and gait analysis
phase. This seems to eliminate the step up' to the pad surface and
provide much more accurate data." The dynamic scan can be viewed in
either 2-D or 3-D. "The unique part," says Sevier, "is that the
step can be viewed frame by frame forward, backward, from any angle
and at any speed. An analysis is available for printout that
compares the patient gait with that of accepted norms."
Then, an order can be placed for orthotics with an unlimited
number of modifications through a menu that creates production
notes via a system of shoe type selection clicks or a modifications
screen for fine-tuning the order, Sevier explains. There is also a
place to enter specific notes for the central lab. At the end of
the day, the laptop is plugged into a standard phone jack and the
data is downloaded to the users' choice of more than seven
different fabrication labs across the country. Says Sevier, "In
seven to ten days, you get your orthotics back priority mail. Cool
stuff!"
An option on the 3DO system is "Request Biomechanical Analysis,"
Sevier notes, although he mentions he has not used it. "A typical
report may include whether the patient pronates or supinates, time
spent in specific phases of the gait cycle, metatarsal flexion /
extension problems, or other gait abnormalities. This is a 'for a
fee' item with the data is currently analyzed by Dr. Craig Lowe of
the Quasar group, an expert in digital biomechanical analysis. The
software that he uses provides a playback of the patient exam. This
differs from other systems, where the system itself compares the
dataset against known points of norm and provides a 'canned'
analysis. These reports are very useful as third-party verification
for insurance."
Greg Storz, CO, CPed, president, Orthocare Orthopedic Services
Inc., Lincoln, Nebraska, also reports that he has used the Quasar
Group 3DO scanning system for several months, with good results. He
also utilizes foam impression boxes when he feels a conventional
method is needed.
Losing the Touch
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Courtesy of Tekscan |
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However, some practitioners who have tried
automated foot technology systems are less than happy with
computerization. Brian Moore, CPO, Arnold Orthotics &
Prosthetics, Shreveport, Louisiana, says, "I have found that when
the practitioner's hands are taken away from his craft by computers
and scanning devices, both the patient and the practitioner lose
something." Moore feels that the personal casting and hand
manipulation of the underlying tissues in order to fabricate a
custom device is becoming a lost art. However, Moore has tried some
types of automated systems. "I have found that you get the same
results from an OTS insert with some slight modifications," he
says. "I trust my hand casting over any computer-generated model
any day. I believe that only competency can provide a well-fitting
device of any type; whether one relies on a computer to do it for
you is up to the individual."
'Work Still Needs To Be Done'
Many automated foot technology systems seem to fall into two
basic categories, believes Séamus Kennedy, CPed, co-owner of
Hersco Orthotic Labs, Long Island City, New York.
 "The first type uses pressure plates or plantar
foot scans that capture the bottom surface of the foot. Some of
these systems will also show areas of pressure when the foot is
weight bearing. These are two-dimensional methods that will
accurately measure the size of the foot i.e. plantar length, width
at the metatarsals, and possibly arch location. However, in my
opinion, they do not fully and accurately translate into the 3-D
topography necessary to make a custom foot orthotic," he says.
The second type of system uses laser or light scanning
technology to capture the full shape of the foot. "These systems
seem to have sufficient resolution to generate good images of the
foot," Kennedy continues. "However, the difficulty arises in trying
to translate the scanned data into a final orthotic. It is the
machining tolerances of the milling system, whether making the
positive cast or the final orthotic, that determine the quality of
the final product. We had one CAD/CAM system that digitized the
negative cast. The foot could then be modified on the screen, and
an orthotic milled out from a sheet of polypropylene. In concept
and theory the system was very advanced, but in reality the milling
process was not as accurate as we required."
Kennedy comments that although some of the systems currently
available do an adequate job, he does not see any as the clear
leader. However, he sees continuing improvement in both cost and
capability, with many innovations coming directly from the O&P
industry. "I think in time we will see the transition of foot
orthotic manufacture from the traditional methods to integrated
scanner CAD/CAM systems, but some work still needs to be done to
ensure quality and cost."
Recognizing Wrong Information
With automated foot technology, the user must be able to quickly
recognize when the computer is giving the wrong information and be
able to quickly override it, warns Jim Pattison, BSc, CPed (c),
P.A. Euroclogs, Prince Albert, Saskatchewan, Canada.
Pattison has looked at several systems, although he is not at
present using automated scanners. However, he says he has strong
opinions about how some things they predict line up with
conventional models and methods. For instance, he describes,
"people coming through the door who have been to a podiatrist and
say that the orthotics aren't helping their metatarsalgia. What has
happened is their feet were scanned, and the scan called for the
met pad to be put right under the MT heads instead of about 1/4"
proximal to the heads so that it could lift the pressure off the
met heads and simulate the transverse metatarsal arch. When people
tell me that the computer is more accurate, I agree that it might
be in some instances. But you have to know when the information is
wrong and be able to override it. Arch height can be different, but
it is not as variable as the MT pads!"
For casting, Pattison prefers casting foam for most clients, but
uses slipper casting as well for a number of problem feet, such as
hyperpronated feet where he needs to make a deeper cut orthotic of
PCFO that he can't get with casting foam. He also uses slipper
casting for some clients with feet too large to fit in the casting
foam. Slipper casting is his method of choice for mid-tarsal and
mid-foot amputation, where he needs to see the shape of the
residual limb to obtain a good fit with the shoe filler. However,
Pattison says, "Casting foam is a lot quicker to do and provides
work with a lot less mess than slipper casting!"
Technology Can Help
To sum up: Although at this point automated scanning and
fabrication does not replace traditional methods of measuring,
casting, and fabricating, the technology can be a useful and
cost-effective tool to meet a substantial segment of patient needs,
providing good outcomes with significant savings in time and
cost.
For more information on automated foot systems included in
this article, visit www.amfit.com and www.digitalorthotics.com. Along
with the systems discussed in this article, other systems mentioned
by orthotists and pedorthists were Tekscan, Foot Maxx,
Canfit-PlusTM, and Sculptaped. For more information,
visit www.tekscan.com; www.footmaxx.com; for Canfit-Plus,
Vorum Research Corporation, www.vorum.com; and www.sculptaped.com. Note: This is
not a complete list of companies providing automated foot scanning
and fabricating technology.
The O&P EDGE does not endorse any products. Products
discussed in this article are included for informational purposes
only. 
Table Of Contents - November 2004
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