At PFOLA confernce , there was a couple of workshops on the attached document on the proposed terminology and classification of orthotic negative model production terminology and orthotic manufacturing terminology.
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I made some comment and will post them when get time away from mtg; PFOLA are seeking feedback.
What say you?
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Syndesmosis - Diagnosis/Management (Conservative)
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27 year old runner with plantar pain proximal to MH's 2-4.
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Attached Files:
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PFOLA Technical Standards Document: Foot Orthotic Classifications, Definitions, and
Summary of Manufacturing Processes Document.
FOREWARD
There is considerable confusion surrounding foot orthotic terminology and the various processes by which foot
orthotics can be created. The purpose of this document is to serve as a reference for foot orthotic terminology, to
provide for the classification and categorization of foot orthotics, to define the types of foot orthotics, and to
provide a brief and concise description of the multiple processes by which foot orthotics are created.
Standard terminology is essential for communication within and between disciplines, professions, occupations,
agencies, and individuals who deal directly or indirectly with foot orthotics and foot orthotic therapy. Foot orthotic
practitioners, manufactures, researchers, educators, as well as individuals who work in government, insurance, the
legal profession, etc. and who have an interest in foot orthotic therapy must have a common language for effective
communication to be possible. Unfortunately, effective communication about foot orthotics and foot orthotic
therapy has been hindered by improper, inaccurate, inconsistent, poorly defined, or misunderstood terminology.
In the performance of its mission, it is PFOLA’s desire that this document will serve to improve communication,
increase understanding, and promote awareness of and within the prescription foot orthotic industry. This
document must be both accurate and current and to that end PFOLA welcomes any and all comments on subject
matter related to this document and will update this document as necessary for enhancement, correction,
clarification and due to changes associated with changes or advancements in terminology, technology,
methodology, materials, and processes, etc. Those who desire to provide comment or make recommendations to
improve this document may do so by writing PFOLA directly or by e-mail addressed to the Technical Standards
Committee at info@pfola.org.
Foot Orthotic Classifications, Definitions, and Summary of Manufacturing Processes
Document. Updated January 24, 2006
Committee Members:
Christopher Smith, DPM
Mr. Scott Marshall
Mr. Paul Paris
Mr. Jeff Root
Table of contents:
Introduction
Foot Modeling Definitions
Orthotic Device Definitions
Manufacturing Process Summaries PFOLA Technical Standards Definitions – DRAFT Revisions: January 24, 2006
Foot Modeling Definitions
Anatomical Volumetric Foot Model (AVFM). A digital or physical model that captures a person’s three
dimensional plantar foot anatomy when the foot is non-weightbearing, semi-weightbearing, or fully-
weightbearing.
A digital AVFM must use actual 3 dimensional data points taken directly from the foot to duplicate
plantar foot anatomy. The most common examples include laser 3D scanners, stereo-digital 3D imaging
systems, and pin array systems.
A physical AVFM captures foot anatomy through direct contact to duplicate plantar foot anatomy.
The most common examples are plaster of paris casts or foam impressions taken directly from the foot.
Any material or method that uses direct capture of the entire plantar foot anatomy creates an AVFM.
Extrapolated Volumetric Foot Model (EVFM). A digital model that approximates a person’s three
dimensional plantar foot anatomy through application of mathematical models that extrapolate pressure
data, or extrapolate temperature data, or extrapolate light data to form the digital model when the foot is
non-weightbearing, semi-weightbearing, or fully-weightbearing. The most common examples are pressure
mapping systems, photographs and ink or carbon paper imprinting systems.
Orthotic Device Definitions
Foot Orthotic. An in shoe device that braces, supports, or protects the foot or part of the foot.
Prescription Foot Orthotic. An in shoe device that is prescribed by a qualified healthcare professional to
brace, support, or protect the foot or part of the foot.
Anatomical Custom Foot Orthotic (ACFO). An in shoe device that is made directly from an Anatomical
Volumetric Foot Model (AVFM). The AVFM is modified with the appropriate medial and/or lateral arch
fill, lateral column expansion, heel expansion, and intrinsic forefoot and/or rearfoot corrections as defined
by the prescribing physician. The entire dorsal surface of said custom device matches the surface of the
modified, or corrected, AVFM.
Extrapolation System Foot Orthotic (ESFO). An in shoe device that is made directly from an
Extrapolated Volumetric Foot Model (EVFM). The EVFM is modified with the appropriate medial and/or
lateral arch fill, lateral column expansion, heel expansion, and intrinsic forefoot and/or rearfoot corrections
as defined by the prescribing physician. The entire dorsal surface of said custom device matches the surface
of the modified, or corrected, EVFM.
Library System Foot Orthotic (LSFO). An in shoe device that is made from a library of pre-
manufactured shells, pre-manufactured corrected positive molds or pre-determined digital shape files (from
which shells or molds are milled.) The foot orthotic shape is chosen by matching a library shape with either
an AVFM or EVFM.
Functional Foot Orthotic. An orthotic device that is designed to control abnormal motion or abnormal
position of the foot and to control the abnormal motion or abnormal position of the lower extremity that is
affected by the position and/or motion of the foot.
Root Functional Foot Orthotic. A Functional foot orthotic made from an Anatomical Volumetric Foot
Model (AVFM) that is taken with the foot non-weightbearing, the ankle joint dorsiflexed to resistance, the
subtalar joint held in its neutral position, and the midtarsal joint fully pronated.
Manufacturing Process Summaries
The following summaries are generic descriptions of various foot orthotic manufacturing processes
Anatomical Custom Foot Orthoses
1. A physical AVFM – Manual Corrected Model -- Manual Orthotic Shell
An AVFM is filled with plaster to create positive model > lateral and medial expansions and intrinsic
corrections are added manually as per prescription > orthotic shell is vacuum formed over corrected
positive model > shell is ground to fit shoe and patient’s foot > extrinsic components and top cover are
added > orthotic device is finished.
2. A physical AVFM -- CAD/CAM Corrected Model -- Manual Orthotic Shell
An AVFM is digitized using a 3D scanner > digital 3D model is modified with lateral and medial
expansions and intrinsic corrections using CAD software as per prescription > corrected positive model is
milled using CAM software > orthotic shell is vacuum formed over corrected positive model > shell is
ground to fit shoe and patient’s foot > extrinsic components and top cover are added > orthotic device is
finished
3. A physical AVFM -- CAD/CAM Corrected Model -- CAD/CAM Orthotic Shell
An AVFM is digitized using a 3D scanner > digital 3D model is modified with lateral and medial
expansions and intrinsic corrections using CAD software as per prescription > orthotic shell is milled
directly from orthotic material to fit shoe and patient’s foot using CAM software > extrinsic components
and top cover are added > orthotic device is finished
4. A Digital AVFM – CAD/CAM Corrected Model -- Manual Orthotic Shell
A digital AVFM is modified with lateral and medial expansions and intrinsic corrections using CAD
software as per prescription > corrected positive model is milled using CAM software > orthotic shell is
vacuum formed over corrected positive model > shell is ground to fit shoe and patient’s foot > extrinsic
components and top cover are added > orthotic device is finished
5. A Digital AVFM – CAD/CAM Corrected Model -- CAD/CAM Orthotic Shell
A digital AVFM is modified with lateral and medial expansions and intrinsic corrections using CAD
software as per prescription > orthotic shell is milled directly from orthotic material to fit shoe and patient’s
foot using CAM software > extrinsic components and top cover are added > orthotic device is finished
Extrapolation System Foot Orthoses
1. EVFM – CAD/CAM Corrected Model -- Manual Orthotic Shell
An EVFM digital file is modified with lateral and medial expansions and intrinsic corrections using CAD
software as per prescription > corrected positive model is milled using CAM software > orthotic shell is
vacuum formed over corrected positive model > shell is ground to fit shoe and patient’s foot > extrinsic
components and top cover are added > orthotic device is finished
2. EVFM – CAD/CAM Corrected Model -- CAD/CAM Orthotic Shell
An EVFM digital file is modified with lateral and medial expansions and intrinsic corrections using CAD
software as per prescription >orthotic shell is milled directly from orthotic material to fit shoe and patient’s
foot using CAM software > extrinsic components and top cover are added > orthotic device is finished
Library System Foot Orthoses
1. Physical AVFM -- CAD/CAM Corrected Model -- Library of Pre-made Orthotic Shells
A physical AVFM is digitized using a 3D scanner > digital model is modified with lateral and medial
expansions and intrinsic corrections using CAD software as per prescription > corrected digital model is
compared to a library of shell shapes and appropriate shell is chosen > library shell may be modified to fit
shoe and patient’s foot > extrinsic components and top cover are added > orthotic device is finished
2. Physical AVFM -- Library of Corrected Models -- Manual Orthotic Shell
A physical AVFM is measured manually or digitized using a 3D scanner > measurements or digital 3D
model is compared to a library of corrected model shapes and the appropriate model is chosen > orthotic
shell is vacuum formed over library model > shell is ground to fit shoe and patient’s foot > extrinsic
components and top cover are added > orthotic device is finished
3. Physical AVFM -- Library of pre-made Orthotic Shells
A physical AVFM is compared to a library of shell shapes and appropriate shell is chosen > library shell
may be modified to fit shoe and patient’s foot > extrinsic components and top cover are added > orthotic
device is finished
4. Physical AVFM -- Library of Shell Shape Files -- CAD/CAM Orthotic Shell
A physical AVFM is measured manually or digitized using a 3D scanner > measurements or digital 3D
model is compared to a library of shell shape files and the appropriate file is chosen > orthotic shell is
milled directly from orthotic material to fit shoe and patient’s foot using CAM software > extrinsic
components and top cover are added > orthotic device is finished
5. Digital AVFM -- CAD/CAM Corrected Model -- Library of Pre-made Orthotic Shells
A digital AVFM is modified with lateral and medial expansions and intrinsic corrections using CAD
software as per prescription > corrected digital model is compared to a library of shell shapes and
appropriate shell is chosen > library shell may be modified to fit shoe and patient’s foot > extrinsic
components and top cover are added > orthotic device is finished
6. Digital AVFM -- Library of Corrected Models -- Manual Orthotic Shell
A digital AVFM is compared to a library of corrected model shapes and the appropriate model is chosen >
orthotic shell is vacuum formed over library model > shell is ground to fit shoe and patient’s foot >
extrinsic components and top cover are added > orthotic device is finished
7. Digital AVFM -- Library of pre-made Orthotic Shells
A digital AVFM is compared to a library of shell shapes and appropriate shell is chosen > library shell may
be modified to fit shoe and patient’s foot > extrinsic components and top cover are added > orthotic device
is finished
8. Digital AVFM -- Library of Shell Shape Files -- CAD/CAM Orthotic Shell
A digital AVFM is compared to a library of corrected shell shape files and the appropriate file is chosen >
orthotic shell is milled directly from orthotic material to fit shoe and patient’s foot using CAM software >
extrinsic components and top cover are added > orthotic device is finished
9. EVFM -- CAD/CAM Corrected Model -- Library of Pre-made Orthotic Shells
An EVFM digital file is modified with lateral and medial expansions and intrinsic corrections using CAD
software as per prescription > corrected digital model is compared to a library of shell shapes and
appropriate shell is chosen > library shell may be modified to fit shoe and patient’s foot > extrinsic
components and top cover are added > orthotic device is finished
10. EVFM -- Library of Corrected Models -- Manual Orthotic Shell
A EVFM digital file is compared to a library of corrected model shapes and the appropriate model is chosen
> orthotic shell is vacuum formed over library model > shell is ground to fit shoe and patient’s foot >
extrinsic components and top cover are added > orthotic device is finished
11. EVFM -- Library of pre-made Orthotic Shells
An EVFM digital file is compared to a library of shell shapes and appropriate shell is chosen > library shell
may be modified to fit shoe and patient’s foot > extrinsic components and top cover are added > orthotic
device is finished
12. EVFM -- Library of Shell Shape Files -- CAD/CAM Orthotic Shell
An EVFM digital file is compared to a library of shell shape files and the appropriate file is chosen >
orthotic shell is milled directly from orthotic material to fit shoe and patient’s foot using CAM software >
extrinsic components and top cover are added > orthotic device is finished -
I realize this post is more than a month old, but something strikes me as warranting encouragment of discussion on it. If this were your document, what would you exclude? What would you endorse? I didn't note much discussion on it but some of the terms concern me as they seem to reflect a lowering of standards from even a year ago.
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I have on my ever expanding 'do list' (in the context of the Arena'ettes being more than their usual high maintainence) to respond to PFOLA with my views, as I do not think the classification adequately covers the prefabricated foot orthotics and the pathway to their prescription. However, I do acknowledge that these are the Prescription Foot Orthotic Laboratory Association terminology guidelines.
I will post my feedback when get to it. -
Attn Jeff Root
As you are the current vice president of PFOLA, and as you yourself admitted to being on the committee that wrote this, how about if you took the time to share how this document was put together, and the rational for various definitions? For example, the term
extrapolation
Extrapolation implies deriving data from a given set of known points, in one unit of measure, and predicting points outside an array of known points in the same unit of measure. I don't see this to be the case in its use any more than if I were to say, "Every 3 feet I find an apple. There must be a pear in 20 yards". Do you see how it would make so much sense that that pear really is 20 yards away, forgetting the fact that I'm actually in a an orange grove?
Also, how is a libraried product ever to be considered a prescription orthotic, and why would it even be recognized as a prescription orthotic if in fact it is not directly or through an automated process, made from the patient's foot?
Why has Pfola expanded its definition of orthotics to include prefabs?
In another thread, you mentioned apathy. In that same thread, you basically said you didn't have time to participate, and yet, you had time to post, and would have time to respond to an email. Does this mean you also use a different unit of measure when typing an email than you do typing a response in a forum?
These concepts come to mind as glaringly different than pfola's attitude years earlier. -
Joe
The purpose of the document is not to support or defend any particular type of foot orthotic or production method. It was to define them.
You and I might not like the use of some of the extrapolation systems (eg Footmaxx) or the use of library shells, but they are being widely used and need to be defined (we can debate the merits of different production pathways elsewhere).
This is especially the case for 3rd party reimbursement. For eg, if a lab is using a library system are they passing the cost saving on to the prescriber (most that I know of are), but more importantly is the prescriber passing that cost saving on to the patient (or 3rd party payer)? .... probably not.
SO the document was the first step in showing 3rd party payers what a true volumetric model is and the different production pathways options, so that payment can be scaled appropriatly.
Imagine the scandel if a lab is using a library system, but is "secretive" about it and it gets out that they are doing this --> this will hurt the whole industry (there was a lab that used to doing this secretly -- but guess what?...you hear very little from them these days and they not a big lab any more..). I do not have a problem with the use of libarary systems, but expect that lab to be open about it; to inform me; and to give me a choice (I may choose not to use it)
The problem I mentioned above is the need for the document to cover prefabricated orthotics that are prescribed without any volumetric or extrapolated modelling .... a prefab is really just a libarary system that the prescriber uses "off the shelf" without modelling (unless you call guessing the arch height, modelling before you use a different type of prefab device) - I think that needs to be better defined in the document to educate 3rd party payers about that pathway.Last edited: Dec 11, 2008 -
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Jeff and Colleagues:
Like Craig, I was going to respond to the PFOLA paper of orthosis definitions but until now, never found the time.
Here are my suggestions:
Don't use the term "volumetric" to describe a three dimensional (3D) image of the foot. Volume only defines a quantity of material not a shape. A sphere, flat-sided box and an egg-shaped object may all have the same volume, but have very different 3D shapes. Also, suggesting that 2D data can be "extrapolated" to approximate a 3D shape is tenuous, at best. With these ideas in mind, the new classifications would be:
Anatomical Volumetric Foot Model = True 3D Foot Model
Extrapolated Volumetric Foot Model = Extrapolated 2D to 3D Foot Model
The term "orthosis" not "orthotic" should be used throughout the document.
Here are the only two orthosis definitions that you definitely need:
Pre-made foot orthosis definition: A pre-made foot orthosis is an in-shoe medical device that is not made from a custom mold of the plantar foot and which is intended to alter the magnitudes and temporal patterns of the reaction forces acting on the plantar aspect of the foot in order to allow more normal foot and lower extremity function and to decrease pathologic loading forces on the structural components of the foot and lower extremity during weightbearing activities.
Prescription foot orthosis definition: A prescription foot orthosis is a custom fit in-shoe medical device that is made from a custom mold of the plantar foot, prescribed by a qualified health-care professional and which is designed by that professional to alter the magnitudes and temporal patterns of the reaction forces acting on the plantar aspect of the foot in order to allow more normal foot and lower extremity function and to decrease pathologic loading forces on the structural components of the foot and lower extremity during weightbearing activities.
I don't know if we need definitions for "functional foot orthosis" and "Root functional orthosis" since they would both be considered to be included under the heading of "prescription foot orthoses".
If "library system foot orthosis" needs to be defined, make certain it is understood that this type of orthosis should be included under the heading of pre-made foot orthoses, nothing more, nothing less. This is very important to maintain the credibility of this document.
That is all I have time to write on during my lunch break. Hopefully others can give some good suggestions also. -
Last edited: Dec 12, 2008
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Syndesmosis - Diagnosis/Management (Conservative)
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27 year old runner with plantar pain proximal to MH's 2-4.
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