As recently as the early 1980s, utilization of computer-aided design and
computer-aided manufacture were viewed as experimental and caused concern about
the changing industry. However, during the past 30 years, computerization has
come to revolutionize practice, allowing clinicians and technicians to focus
less on time consuming techniques and enabling them to provide better patient
Practitioners who were looking for better, faster and more economical
methods to provide services may have found the answer with computer-aided
design (CAD) and computer-aided manufacture (CAM).
“One of the main attractions of CAD and CAM is the potential time
and cost reduction over traditional methods, particularly if central
fabrication is used,” Joan E. Sanders, PhD, professor of
bioengineering at the University of Washington in Seattle, said.
© iStockphoto.com & James Wynne
“The likely future changes in reimbursement will make CAD and CAM a
good alternative for many practitioners,” Sanders told O&P Business
News. “The time savings for the practitioner to design and make
sockets, once CAD and CAM techniques have been learned, are high.”
CAD and CAM also provide practitioners with an electronic record of
patients shape and measurements. As the health care arena incorporates
electronic records into practice, “CAD and CAM technology will play a key
role in enhancing the clinical history of the patient,” said James H.
Wynne, CPO, FAAOP, vice president and director of education at Boston
Brace/National Orthotic Prosthetic Company.
“This, coupled with the need to report patient outcomes in order to
sustain efficacy of treatment for third-party payers, adds to the usefulness of
CAD and CAM in the clinic. It is not just for capturing the shape of the
patient but it is a key component for clinical records and outcome
measurement,” he added.
O&P Business News spoke with several experts in the field to
share their thoughts on the benefits of CAD and CAM technology, hindrances with
use and potential developments down the road.
According to a paper published in Physical Medicine and
Rehabilitation Clinics of North America, many prosthetists initially feared
that the launch of CAD and CAM would give other health care professionals the
opportunity to fit and manage amputees, thus jeopardizing their jobs. Likewise,
technicians thought they would be replaced by computerization and automatic
Over time, it has become clear that both technologies have provided many
benefits to the industry. Most significantly, clinicians have more time for
improved patient care and have an accurate way to more efficiently capture and
manage shapes and design.
According to David M. Gerecke, CPO, FAAOP, owner of Active
Prosthetics & Orthotics, PC in San Antonio, Texas, the field of prosthetics
and orthotics has long valued “hand skills,” or the ability to
capture and manage shapes through a variety of shape capture methods. These
methods include measurements, tracings, plaster casts, photos, radiographic
images and, more recently, three-dimensional digital models that can turn
shapes into devices used in practice.
“CAD and CAM allows opportunities that include increased shape
management options, increased production capability, increased access to
outsourced fabrication, increased business opportunities for technicians, and
the ability to provide full-service P&O care to communities that may not
support a business using traditional on-site manual fabrication,” he said.
CAD and CAM revolutionized prosthetic practice over the years by
allowing for mobility room to room in the clinic, as well as easier
outsourcing. Quick scanning can be electronically transferred and saved to a
central fabrication facility in seconds, resulting in reduced shipping costs,
turnaround time and reduced time constraints waiting for the plaster/fiberglass
to set and cleaning the room.
Additionally CAD and CAM has opened the door to more business ventures.
Gerecke believes that due to the ease of transmitting digital files instead of
plaster models or delicate negative impressions, technicians now have more
opportunities to own their own fabrication facilities.
“One of the more revolutionary aspects of CAD and CAM is the
separation of clinical practice from traditional fabrication methods,”
Gerecke said. “CAD and CAM allow the prosthetist/orthotist to partner with
fabrication experts around the country (or world) in the fabrication of these
Cost may be an impediment to using these tools in the field. Significant
investment in software and hardware is needed, which is not reimbursable.
“The CAD and CAM manufacturers have worked tirelessly to design
software and hardware systems that are affordable and symbiotic with the
standards of conventional clinical prosthetic and orthotic measurement
techniques,” said Michael J. Nunnery, CPO, owner of Nunnery
Orthotic & Prosthetic Technologies and a researcher in the Neuromuscular
Engineering Laboratory at the University of Rhode Island.
Pros and cons
CAD and CAM give the practitioner the ability to maintain focus on
clinical operations, provide for access to expert fabricators that is not
limited to what the practitioner can teach, and increase the number of shape
capture options and tools available to manipulate those shapes.
It also enables the user to create shapes using radiographic data (ie,
X-ray, MRI, CT), photographs and other visual data, and allows for increased
“CAD and CAM are not inherently better or worse than, or even
exclusive to plaster modeling,” Gerecke told O&P Business News,
but they do “offer the clinician and technician more control over shapes
with many more tools available than in plaster modeling.”
Sanders believes an important benefit is faster made, more consistent
sockets and the ability to easily make a duplicate or modify a socket or
“The cost reduction in terms of less time required by the
practitioner to make a socket is also a plus, and will likely be the primary
feature to drive up CAD and CAM use in prosthetics and orthotics in the
future,” she said.
Nunnery, who is also chair of the CAD/CAM Society of the American
Academy of Orthotists and Prosthetists, has been using CAD in his practice for
more than a decade and has success in clinical prosthetic management with
protective face masks and with cranial remolding helmets.
“CAD allows the clinical practitioner to utilize digital shape
capture as a means of obtaining consistent non-contact shape images. This
allows the practitioner to have a well-documented ‘digital trail’ of
the patient’s historical anatomical or volumetric changes,” he told
O&P Business News. “Conventional casting methods are widely
used; however, it is difficult to maintain a vast library of the physical
models and molds for most practices. Digital scans, shapes and models are kept
on file forever with proper security and backup. It is very simple to compare
models and scans that are years apart, and great for record keeping.”
CAM, on the other hand, allows for quick carving of models and
fabrication of prosthetic sockets, custom liners and various orthotic devices.
CAD and CAM techniques, compared with conventional methods, make it easy
for the user to refer back to baseline, according to Wynne.
“It is much cleaner and faster for the patient, and there is a
complete history of the modifications that can be undone or modified prior to
fabrication,” he said.
From a business management perspective, Gerecke added that CAM keeps
patient care areas cleaner because it separates the clinical practice from the
fabrication area. This, in turn, provides for increased opportunities to house
practices in medical office buildings or hospital environments.
Although there is an added expense for the technologies, they may be
potentially more cost effective in the long run.
Other challenges besides the cost of investing in a CAD/CAM system
include the need for a learning curve, since the technologies and knowledge
base of the users may vary; complicated software and hardware systems; and lack
“Regardless of one’s years of experience, implementing CAD and
CAM requires an understanding that there is a learning curve for those who are
new to using it,” Nunnery said.
Sometimes, the challenge is in “knowing that if I invest in the
technology and time to become skilled at CAD, I can be sure the manufacturers
will continue to develop new hardware and software advances for us to
utilize,” Nunnery added.
Sanders said different steps in the current CAD/CAM fabrication process
may cause inconsistent measurements, resulting in an imprecise socket. Limb
size and volume changes that occur between doffing and scanning are issues that
can introduce error to the measurement, according to Sanders.
“CAD and CAM systems will improve as fabrication technologies
improve, causing greater use in prosthetics and orthotics,” she said. In
addition, “once reimbursement changes to the point that practitioner time
must be used more cost effectively, CAD and CAM technologies will be a more
popular option, driving practitioners to the technology.”
Sanders highlighted some CAD/CAM research projects under way that may
emerge over the next few years. For example, direct socket fabrication does not
use a positive model as part of the fabrication process, so no plaster or foam
is left over to discard.
“Reducing the number of steps and using a state-of-the-art
fabrication technology potentially makes direct socket fabrication more
accurate,” she said. “The drawbacks are that it takes a long time to
make each socket, and socket material choice is very limited.”
Non-shrinking definitive socket material is also in the pipeline, which
would prevent materials from shrinkage during the socket-forming stage of
CAD/CAM that causes distortion. There is also potential for self-adjusting
technologies and self-correct fabrication errors, where computers
‘learn’ practitioner methods.
In addition, overall enhancements to the design software are under way.
“One of the beauties of CAD and CAM is the potential to design new
features into sockets that currently do not exist. Once useful socket features
become possible with CAD and CAM that are not possible with traditional
methods, CAD and CAM use will likely increase,” Sanders said.
Nunnery said he is looking forward to additional research on 3-D printer
technology, laser scintering and other advanced manufacturing technologies that
may help to reduce some of the steps in obtaining final finished products.
Wynne said preliminary results of a brace simulator in development will
be published soon. This brace would allow the orthotist to scan a scoliosis
patient, merge it with the electronic x-rays and create a 3-D finite element
model of the patient’s spine. This can then be inserted into the scan to
test various brace designs before fabrication.
“It’s very promising. CAD will now allow us to optimize the
design of an orthosis,” he said.
The development of the new carvers, such as the multiaxial carvers that
produce more complicated shapes for faces and pediatric orthotics, is another
area in need of more research.
“Perhaps our digitized, modified model will not need to be carved
to foam for socket or orthosis fabrication, perhaps we can go right to socket
or device manufacturing,” Nunnery said. “I would like to see the
capture hardware made to be less hardwired and more compact, allowing greater
This developing technology has provided new opportunities to grow and
learn. Gerecke said the Academy online learning center CAD/CAM courses that are
available to instructors and students in an educational program are valuable
resources. Nunnery added that development of a standardized curriculum for
programs is needed and would aid in providing content for the Academy’s
online learning center.
Gerecke noted that the Academy’s CAD/CAM Scientific Society
recently formed the CAD/CAM curriculum development committee, which is in the
process of developing these courses. The first course has been submitted,
reviewed by a panel of educators and was recently posted to the Academy’s
online learning center. Several more courses are in development and will be
added as they are finished and reviewed. These courses will be available to all
Academy members, including students and instructors.
“You need to be committed to learning the technology from
competent, experienced clinicians. Become competent in one area of the software
before moving on; repetition is essential so make time in the schedule to
practice,” Wynne suggested for those centers that plan to implement CAD
and CAM technology.
“Start with a few clinicians who want to embrace this technology
and accept that not all practitioners in your practice will want to make the
change,” he said. “Once they become comfortable in scanning and
navigating the CAD and CAM software, I think most practitioners will say
it’s worth the effort.” – by Tara Grassia
Brncick M. Computer automated design and computer automated
manufacture. Phys Med Rehabil Clin N Am. 2000;11(3):701-713.
Clin J, Aubin C-E, Parent S, et al. Comparison of the biomechanical 3D
efficiency of different brace designs for the treatment of scoliosis using a
finite element model. Eur Spine J. 2010;19:1169-1178.
Goh JC, Lee PV, Toh SL, Ooi CK. Development of an integrated CAD-FEA
process for below-knee prosthetic sockets. Clin Biomech (Bristol, Avon).
Houston VL, Burgess EM, Childress DS, Lehneis HR, Mason CP, Garbarini
MA, LaBlanc KP, Boone DA, Chan RB, Harlan JH, Brncick MD. Automated fabrication
of mobility aids (AFMA): below-knee CASD/CAM testing and evaluation program
results. J Rehabil Res Dev. 1992; 29(4):78–124.
Köhler P, Lindh L, Netz P. Comparison of CAD-CAM and hand made
sockets for PTB prostheses. Prosthet Orthot Int. 1989;13(1):19–24.
Labelle H, Bellefleur C, Joncas J, et al. Preliminary evaluation of a
computer-assisted tool for the design and adjustment of braces in idiopathic
scoliosis: A prospective and randomized study. Spine.
Michael JW. Reflections on CAD/CAM in prosthetics and orthotics. J
Prosth Orthot. 1989;1(3):116.
Portnoy S, Yarnitzky G, Yizhar Z, Kristal A, Oppenheim U, Siev-Ner I,
Gefen A. Real-time patient-specific finite element analysis of internal
stresses in the soft tissues of a residual limb: a new tool for prosthetic
fitting. Ann Biomed Eng. 2007;35(1):120–35.
Ruder GK. CAD CAM trans-tibial temporary prosthesis: analysis and
comparison with an established technique. Prosthet Orthot Int.
Sanders JE, Rogers EL, Sorenson EA, et al. CAD/CAM transtibial
prosthetic sockets from central fabrication facilities: How accurate are they?
J Rehabil Res Dev. 2007;44(3):395-406.
Sanders JE, Severance MR, Allyn KJ. Computer-socket manufacturing error:
How much before it is clinically apparent? J Rehabil Res Dev.
Sanders JE, Severance MR, Myers TR, Ciol MA. Central fabrication: carved
positive assessment. Prosthet Orthot Int. 2011;35(1):81-89.
Smith DG, Burgess EM. The use of CAD/CAM technology in prosthetics and
orthotics – Current clinical models and a view to the future. J Rehabil
Res Dev. 2001;38(3):327-334.
Topper AK, Fernie GR. An evaluation of computer aided design of
below-knee prosthetic sockets. Prosthet Orthot Int.
Disclosures: Gerecke worked for Willow Wood as an Omega Tracer training
consultant in 2007 and 2008. Nunnery utilizes the Tracer CAD System from Willow
Wood. Sanders has no disclosures. Wynne works for Boston Brace, which is the US
distributor of Rodin4d.