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I'm curious about how different people decide on whether they will use a hindfoot post in addition to a medial skive vs. just the skive. I assume people avoid the post if they are worried about jamming the medial column of the foot in a patient who has a very medial subtalar joint axis, but how do you make this decision? Also, how often do people use a Blake inverted positive mold? Skive...post...Blake...Aside from practical experience, any other guidelines? Thank you!

Ann

Hi Ann,
I mostly don't use a RF post at all, and post FF only.
Devices work fine.

Cheers,
david

I prefer to use two different terms for rearfoot prescription variables to refer to two different things:

1. Rearfoot posting
2. Rearfoot wedging

Rearfoot posting:
I usually use this when i want to change the position of the rearfoot. The post is added at whatever angle I want the rearfoot to be angled at. Under traditional theory this is effectivly in the "measured" neutral calcaneal stance position. The evidence (which I have presented at many conferences and not yet published) is that when you cast a foot with the foot in STJ neutral and add a rearfoot post to hold the foot in that position (ie NCSP) that the orthotic will hold the cast in the NCSP, but the foot WILL NOT be held in that position ---- however, outcome studies show that when you do this, patients do get better .... so there is a sound rational for doing it, even though the theory underpinning it is questionable.

Rearfoot wedging:
I prefer to use this to differentiate from the concept of rearfoot posting and use this when a greater supinatory moment is needed from the orthoses (ie orthotic reaction force). Wedging is done in 4 ways:
1) Removal of material under the medial side of heel area of the positive model
2) Removal of a specific portion of material on the positive model (ie Kirby Skive)
3) Addition of material on the lateral side of the heel on the psitiove model (ie DC wedge technique)
4) Blake inverted technique
The greater the supination resistance force, the greater the wedging that is needed. Which of the 4 you use comes down to personal preference -- the only other criteria I use for a Blake vs the other 3 is on the amount of transverse plane motion in the midfoot... ie use a Blake if navicular drift > navicular drop.

__________________
Craig Payne
Department of Podiatry
La Trobe University
Melbourne, Australia
http://www.latrobe.edu.au/podiatry
__________________________________________________ ___________________________________
God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.
The views expressed above are those of the author and not that of La Trobe University
This is where I am, where are you?

The BIO is something i do often use in children. They seem to adapt quite easely to the larger amount of correction (it takes them only about 2 weeks). Clinically, they seem to reduce the forefoot supinatus fast and efficient.
The work on positive plastering is a bit more time consuming, but it's worth it seeing the result.

Ken

__________________
Ken Van Alsenoy
Artevelde hogeschool
dept. Podiatry
Ghent - Belgium

Last year, we did a small research project (n=10) on the comparison in effect of the Root orthotic vs a Kirby MHS on a Root orthotic during walking.

We thought that the MHS would work more efficient in the eversion control of the calcaneum at initial heel contact, but on the contrary the classical Root did a better job.
During mid- midstance the MHS had a better eversion control an the calcaneum.
During propulsion the Root has again better control than the MHS.

greetings,

__________________
Ken Van Alsenoy
Artevelde hogeschool
dept. Podiatry
Ghent - Belgium

Ken:

Just for your information, I never prescribe a medial heel skive on a foot orthosis unless that foot orthosis is also inverted by having the positive cast balanced inverted (i.e. I never use a medial heel skive on a vertically balanced Root orthosis). I also always use a minimal medial arch filler on the positive cast if the patient is receiving a medial heel skive orthosis modification. And, by the way, I would not recommend using only forefoot posts on orthoses since rearfoot posts are essential for patients with difficult-to-control feet, like those that require the medial heel skive modification.

If a medial heel skive is added to a positive cast, then effectively the medial arch height is being lowered relative to the plantar calcaneus in the resultant foot orthosis since the medial heel cup is being made more shallow by removal of medial-plantar heel plaster from the cast. To compensate for this, since 1990 when I first started experimenting with the medial heel skive modification, I have used minimal medial arch expansion and an inverted balancing position on the positive cast to make certain that the medial longitudinal arch is also being supported firmly by the foot orthosis.

If the foot orthosis is being designed with the goal of increasing the subtalar joint (STJ) supination moment for a patient that has symptoms being caused by excessive magnitudes of STJ pronation moment (e.g. posterior tibial tendinitis/dysfunction), then I use the appropriate depth of medial heel skive in the heel cup of the orthosis to increase the STJ supination moment plantar to the calcaneus and then use a higher-than-normal medial longitudinal arch height in the orthosis (by inverted balancing and decreased medial expansion plaster thickness in the positive cast) to increase the STJ supination moment at the midtarsal joint/midfoot level.

This increase in STJ supination moment at both the calcaneal and midtarsal joint/midfoot level work synergistically with each other to increase the net STJ supination moment on the foot so that not only increased patient orthosis comfort is achieved but also increased patient symptom relief is achieved. Using the medial heel skive without the concomitant medial longitudinal arch height increase will cause the patient to feel that "the arch of the orthosis is too low" and using the increased medial longitudinal arch height modification without the medial heel skive will generally cause the patient to feel that "the arch of the orthosis is too high".

By trial and error modification of the medial heel skive foot orthoses in thousands of patients over the past 16 years, the above clinical observations not only make good biomechanical sense but have allowed me to achieve quite remarkable success with foot orthoses in numerous foot and lower extremity pathologies that I would have not been able to achieve otherwise. I have previously published these above concepts in the following articles/books:

Kirby KA: The medial heel skive technique: improving pronation control in foot orthoses. JAPMA, 82: 177-188, 1992.

Kirby KA, Green DR: Evaluation and Nonoperative Management of Pes Valgus, pp. 295-327, in DeValentine, S.(ed), Foot and Ankle Disorders in Children. Churchill-Livingstone, New York, 1992.

Kirby KA: "The medial heel skive technique-Volume I, July 1992"; "The medial heel skive technique-Volume II, August 1992"; "New thoughts on the medial heel skive technique, April 1994". In: Kirby KA: Foot and Lower Extremity Biomechanics: A Ten Year Collection of Precision Intricast Newsletters. Precision Intricast, Inc., Payson, Arizona, 1997, pp. 107-112).

Kirby KA.: Biomechanics and the treatment of flexible flatfoot deformity in children. PBG Focus, J. Podiatric Biomechanics Group, 7:10-11, 1999.

Kirby KA: Conservative treatment of posterior tibial dysfunction. Podiatry Management, 19:73-82, 2000.

Kirby KA: "Effect of subtalar joint axis location on arch irritation in orthoses, June 2000";"Orthosis modifications for treatment of posterior tibial dysfunction, April 2000". In Kirby KA: Foot and Lower Extremity Biomechanics II: Precision Intricast Newsletters, 1997-2002. Precision Intricast, Inc., Payson, AZ, 2002, pp. 29-32, 103-104.

__________________
Sincerely,

Kevin

**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College

e-mail: kevinakirby@comcast.net

Private Practice:
107 Scripps Drive, Suite 200
Sacramento, CA 95825 USA
My location

Voice: (916) 925-8111 Fax: (916) 925-8136
**************************************************

Ann
I tend to use medial skives when the patient exhibits large amounts of calcaneal plantarflexion (Subjective assessment) and medially deviated STj axis. Sagitally modified medial skives are also useful to increase function in this plane rather than increasing the medial skive value
Rearfoot posts may be added when rearfoot eversion is seen at very early heel contact in an attempt to decelerate movement but this is questionable.
Rearfoot posts may also act as a sagital plane modifier/accelerater as due to the extra material added to the shell they will 'lift' the rearfoot.
Within bespoke orthoses, worries about blocking function can be addressed with plantar fascial grooves, 1st ray additions, 2-4 scoops etc and I will usually include these facilitating mods to most of my orthoses in addition to the rearfoot and forefoot 'correction'.
It also worth bearing in mind the spatial alignment of the centre of rotation of the ankle (plantar aspect) as rearfoot posts may increase plantarflexion moments - not ideal with tib ant dysfunction. In these cases I will use smaller rearfoot posts and use medial skives more plus a SACH mod. (A softer density material replaces the rearfoot post at the extreme posterior section - 'dampens' pf moments.
All very subjective stuff but it works for me.

Phil

I tend to use a bit of a hybrid mix...I make a blended cross between a Blake and Mod Root with minimal medial plaster added some times and I use the DC style rear foot wedge.(made by adding plaster to the lateral heel).particularly with significant tibial varum and tib post failure. I also use forefoot lateral wedging quite a bit. What Kevin has to say about plaster work for heel skives is something I agree with from personnel experience..he probably does not remember but I brought it up with him via the net 7-8 yrs ago. Not a big fan of forefoot posting medially....do it very rarely...seem to get reasonable results...offer money back guarrantee with return of devices and am yet to be asked to refund.
regards Phill Carter

Also a fairly big fan of sagital plane calc inclination angle / cuboid lateral column support, find myself making things much more supportive here than the labs in my area, it seems they are reluctant to make that kind of shape ...and being that extra step removed from the patient does not help them to know when it may be the key to better results.

Kevin,

Thanks for your reply. Our discussion on the results came out more or less the same. We were thinking that problem was indeed the medial arch hight because you skive the plaster but not the foot. The shape of the medial arch filler was a straight line from the sustentaculum tali to the forefoot platform. We also discussed the possible paralax problems in the heel contact and propulsion fase because we were using 2D and not 3D kinematic measurements.

If we make an orthotic device with a MHS in a patient situation, we do use minimal medial arch filler and a heelcup to control the rearfoot - for the project we had it standard on 2cm. The MHS was 15°.
I wasn't suggesting that the MHS didn't work as it should, but we wanted to have a minimal amount of variables, and this obviously affected the positive effect of the MHS which we do find clinically.

I was wondering if you mark the position of the STJ axis, and you would make your skive relative to that position and not to the standard 2/3 -1/3 ratio + taking your remarks stated above into account.
Wouldn't the skive be more effective (> inversion moment)?

regards,

__________________
Ken Van Alsenoy
Artevelde hogeschool
dept. Podiatry
Ghent - Belgium

Ken:

I think your research has value. However, your research probably isn't very useful for the clinical world we work in since the medial heel skive is not a "combined orthosis technique" as the Blake Inverted Orthosis is and should probably not be used clinically, as you did in your research, just simply adding the medial heel skive to a standard orthosis with no other modifications included. Soon after I published the paper on the medial heel skive I realized that I probably should have included a more detailed analysis on how I utilized the medial heel skive along with other orthosis prescription variables. However, JAPMA may not have accepted a longer paper for publication.

I have been asked the question about marking the STJ axis on the cast to properly position the medial heel skive now for past 10+ years. To put it simply, you don't really need to know the spatial location of the STJ axis to know that a medial heel skive will increase the STJ supination moment. As long as the ground reaction force (GRF) is shifted more medially on the plantar foot by the orthosis, then an increase in STJ supination moment will result. Therefore, an increase in STJ supination moment may be specifically accomplished by a foot orthosis in two ways:

1. Increasing the magnitude of GRF medial to the STJ axis.
2. Decreasing the magnitude of GRF lateral to the STJ axis.

Both of these alterations in GRF on the plantar foot will cause a shift in center of pressure (CoP) more medially on the plantar foot. However, the CoP does not need to be medial to the STJ axis in order to generate an increase in STJ supination moment. The CoP simply needs to be more medial than it was previously in order to have the CoP cause an increase in STJ supination moment.

And, very importantly, you can not simply rely on the relative position of the CoP to the STJ axis to determine whether a net STJ supination or net STJ pronation moment is acting on the foot at any instant in gait since the CoP position on the plantar foot will be greatly affected by extrinsic muscle activity acting on the foot. For example, the CoP will nearly always tend to be lateral to the STJ axis when the patient is standing in relaxed bipedal stance since the Achilles tendon is nearly always medial to the STJ axis and gastroc-soleus muscle activity will shift the CoP lateral to the STJ axis. CoP to STJ axis position only determines the mechanical effects of GRF on the STJ, not the net STJ pronation-supination moments from all sources. This is a critically important point to realize so that the limitations of pressure mat/insole/force plates in determining STJ moments may be understood.

__________________
Sincerely,

Kevin

**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College

e-mail: kevinakirby@comcast.net

Private Practice:
107 Scripps Drive, Suite 200
Sacramento, CA 95825 USA
My location

Voice: (916) 925-8111 Fax: (916) 925-8136
**************************************************

Hi all,

On when to use Medial Heel skive: Use it when there is a medially deviated STJ axis. Which is essentially what Craig said about using with a high resistance to the supination resistance test.

On control of calcaneal position with root vs. medial heel skive. The patients should be devided into sub groups. Those with more medial STJ axis position should do better with the skive and those with more lateral position, I would predict, would do better with the Root in terms of calcaneal eversion. Some people have pronation caused by the Ground and others have pronation caused by muscles. The skive is attempting to decrease the pronation moment from the ground. Those with more laterally deviated STJ axes will tend to have the ground supinate their STJ and in response they will use their peroneal muscles to pronate thier foot to prevent ankle sprains. I call these people muscular pronators. When you add a device with a medial heel skive to a musclular pronator you will occaisionally see increased late stance phase pronation.

The above illustrates one of the brilliant observations made by Root et al. They maintained that you have to classify feet in order to study them. Not all feet will respond the same way to the same modification. I would rather classify feet by STJ axis position than forefoot to rearfoot measurement.

Cheers,

Eric Fuller

Book Antiqua

Hello All,

I have somewhat of a different view on the usage of Rearfoot posting, wedging or any other attempt to tilt the ground in the frontal plane in order to achieve orthotic gait corrrection.

I feel heel posting should not be used reguardless of Diagnosis, foot type, orJ shadows on the plantar foot surface of the foot. I have identified five reasons that rearfoot posting is not a good apporach to correct overpronation.

1. Geometry
The heel is rounded on the plantar surface, and so is the heel cup of the orthoses. A ball in socket. I bet if you put the femur in the acetabulum it couldn't move (NOT). Naturally, the foot, upon entering the shoe will seek its own position. Certainly a two or four or even seven degree tilt is meaningless. We have experimented with up to 10 degree wedges and posts and found them to have no effect on calcaneal eversion either during standing or walking.

2 Soft Tissue Interposition
Between the skin and the bone is a rather large fat pad and a fluid filled thick fibrous bursae designed to fascilitate sliding motion. We took 50 people and marked their calcaneal bisections and proceded to move the overlying skin 7-10 degrees in both directions in all subjects. Admittedly, none had scleroderma. But subjects were thin, fat etc. Here we are measuring 4 degrees of rearfoot varus, with a 3 degree error in the goniometer, a 7-10 degree error in the soft tissue and according to Craig Payne's Jan 2003 Japma a 15 degree error in the cast. The errors dwarf your measurement.

3. Time Force = mass x acceleration (Isaac Newton)
Acceleration is a change in velocity in a unit of time:

F=m x Change in Velocity / time

Velocity is a change in position in a unit of time

F = m x change in position / time to the second power

Force is inversly proportional to the square of time.

English Translation: If you have a little force and want to do some work it will take a lot of time.
Dig a canyon in 10,000,000yrs. with a river (Grand Canyon)
or 5 minutes with an earthquake (more force.... less time)

There is simply not enough time, for the 2, 4, or 7 degree wedge to ITSELF apply an adequate force to counteract the 3+ times body weight at heel contact. We need an orthotic therefore that creates time. There is one.

4. Tourque = force x perpendicular distance
Distance is measured from the force to the axis. At heel contact, the axis of the STJ passes through the point at which the heel contacts the ground. The distance is zero.... NO torque.....No motion.


We need a completely different approach to control of the foot in gait and rearfoot posting has no place in it.

How about we replace this concept with rearfoot supination through placing the foot in the maximal amount of supination dynamically possible at midstance, the MASS (Maximal Arch Stj Stabilization Position) as opposed to neutral position (also a fantasy), go in full contact with that shape of the foot, and calibrate the orthotic to deliver an equal and opposite force to what the foot is putting through the orthotic. Then prepare the foot to hit the ground by maintaining the supination of the foot at toe-off through the swing phase thus leveling the anterior facet of the STJ and "dampening" pronation (creating a time delay) adequate to bring hyper-pronated gait cycle to as close to an ideal gait cycle as the individual patient can tolerate with their anatomy.

Rearfoot posting is a fantasy. It was probably invented in Universal Studios by a young engineer named Spongebob Squarepants.

Besides, correcting a four degree varus with a four degree post is assuming 100% efficiency of both the foot and the orthoses. It is so "Frontal Plane".

Let me know what you all think.

Respectfully,
Ed Glaser, DPM

Ed:

I am so happy you responded to Podiatry Arena. I received your video presentation that you sent to many podiatrists in the US that described many of your "new" ideas about foot biomechanics and foot orthoses. From viewing your video and visiting your website http://www.solesupports.com/index.htm , it honestly seems to me that you don't have any new ideas. In fact, it seems to me that you are simply rehashing the same ideas that we have been talking about in podiatric biomechanics for the past two decades and using that rehashed material to promote your company's products. Maybe you can enlighten us further, but these were my first impressions in viewing your video and looking at your website.

However, I am very impressed with your testimonials on your company's website http://www.solesupports.com/testimonials.htm since this certainly lends considerable scientific credibility to your ideas and your company's products. I believe that Dr. Brian Rothbart has used similar marketing techniques on his websites where he preaches about the virtues of his ideas and his insole product.

Also, let me take a wild guess.....could the "one" orthosis you talked about in your posting above just so happen to be the orthosis made by your company, Sole Supports??

Please enlighten me, Ed, how has your book, "The Bottom Block" strengthened the foundation of the field of biomechanics as you claim on your company's website??? http://www.solesupports.com/glaser.htm

By the way, with all the research that you say that you have done, has any of your research ever been published in a peer-reviewed journal??? If not, then why not???

__________________
Sincerely,

Kevin

**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College

e-mail: kevinakirby@comcast.net

Private Practice:
107 Scripps Drive, Suite 200
Sacramento, CA 95825 USA
My location

Voice: (916) 925-8111 Fax: (916) 925-8136
**************************************************

Sorry to seem picky, but I also question the "accuracy" of someone that spells torque incorrectly...it can't be a typo because "r" and "u" are so far apart on the keyboard!

....he's from Nashville and has had to put up with me all day ... that might explain it

__________________
Craig Payne
Department of Podiatry
La Trobe University
Melbourne, Australia
http://www.latrobe.edu.au/podiatry
__________________________________________________ ___________________________________
God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.
The views expressed above are those of the author and not that of La Trobe University
This is where I am, where are you?

Kevin,
Thank you for identifying my website, product etc. I believe you are also connected to a commercial product. I find your critique very humorous but lacking in substance. Attacking the “newness” of my ideas has nothing to do with the substance. What I am saying is that the Kirby skive, or any frontal plane wedging is simply a variation on the theme of frontal plane Rootian biomechanics. If your major criticism is that these ideas are not “new” then why are you not using them? Are you still using “Neutral” position, or are you using the MASS position? You are obviously still using posting and skives (wedging). I invite all to go to my website and view the DVD which is now posted on line. It is just my regular lecture. I will be at the Western Congress in LA this weekend teaching this course as a workshop. Why not let people look at the course and then decide for themselves how “new” it is.

You are correct. Although I have been delivering this lecture since 1992, I have not published for many reasons. Firstly, I felt that the theories were incomplete and I was going up against a very entrenched biomechanical norm. Secondly, I was afraid that some would take these theories and misapply them before I had a chance to test them completely (as is now being done …. I see everyone including yourself jumping on the “lower the head of the first” bandwagon). Unfortunately, it is being mixed with older posting and wedging theories and even older padding techniques. Thirdly, you are correct… I am the CEO of Sole Supports, Inc. and it was partly a smart business decision to keep our theories within the circle of certified practitioners that are allowed to use our technology in order to prevent run-away growth of the company. We have had a difficult enough time dealing with the enormous growth we have experienced without one single advertisement for our product.

What I question is:… What is the importance of chasing the shadow of the STJ axis in the open chain on the bottom of the foot when:
1. this axis is a moving target
2. looking at the STJ as axial is a gross over simplification
3. the joint is not even axial in the closed chain

If Craig is right (and I believe he is), that neutral suspension casting averages 15 degrees variability in the frontal plane alone. Why add another variable….pushing down some variable degree on the head of the first while dorsiflexing the MTP and inducing the windlass effect. Open chain casting has no frame of reference and is therefore unreliable and non repeatable. That’s why so many labs “cast correct”.

We certainly cannot effect foot function without applying a force. Any cast correction or arch fill takes away from the full contact of the orthoses. We cannot apply a force through thin air. Putting the foot in an unreliable and incorrect position while pre-pronating it by pushing up on the fourth and fifth, then filling the arch (further pronation) and then tilting the ground a few degrees so that the person is walking along the peak of the roof is silly. Walk outside. Every step you take is several degrees different in the frontal plane.

Gait referenced MASS position casting answers these concerns. It captures the foot at the maximal amount of supination available at midstance which externally rotates the talus onto the anterior facet of the STJ blocking sagital plane rotaton around the cone shaped posterior facet. This sagital plane locking allows the foot to lever at the ankle axis for propulsion. If the rearfoot is stiffer (not locked...thanks for that Craig) in the sagital plane, then when the Center of Gravity passes the heel and we go into heel lift, we have a propulsive gait. Check out the "Goals of Biomechanics" section of the lecture.

About the spelling…. You will find that I stink at spelling so I will write these passages in the future in Word and use the spell checker. If misspelling a word is the worst criticism that can be launched against my theories....that’s fantastic.

Oh, and you guessed correctly. I am referring to Sole Supports. We walk the talk. Why would I recommend anything less effective. If you are going to go Full Contact, you should do it accurately, repeatable, in the closed chain, dynamically (passing weight through the foot in as close to the ideal gait cycle as the patient can tolerate with their anatomy) and place the foot in the MASS position….not neutral (which turns out to be the problem and not the solution).

Knowing that the foot heel strikes in supination, why would anyone in their right mind allow the foot to pronate all the way to “neutral” before beginning to think about controlling it? And then we cast correct (arch fill) and allow the foot to pronate even more!!! By then the momentum of the body is driving the foot to even greater pronation. We suggest you prepare the foot for heel contact by increasing the degree of supination at heel contact, leveling the anterior facet and slowing down the pronatory process.

I knew one PT who was ordering 28 – 32 degree posts (more aggressive than even your skive) before he noticed changes in function. I argued that when you add that much post… you are finally creating an arch.

Hey… this is fun.
Keep it up.
Ed :)

Kevin,
Testimonials are for the lay public. Annecdotal evidence is just that. Lets take that further. Relief of symptoms is a poor indicator or changes in foot function. Studies show quite clearly that rootian orthoses (with or without skives) are no more effective than prefabs at covering up symptoms. In fact they are both usually quite successful. I am attempting something quite different here.... to change foot function because I believe that "form follows function". If we are ever to differentiate ourselves from Alzner or Dr. Scholls OTC orthoses we must predicate our success on modification of function. This takes an agressive appliance. Skives are wimpy.
Ed

Ed
Is this approach a 'cure all'? Don't we need to pronate a bit are are you saying that the soft tissue flexibility will allow this?
E.G - What would you do for the patient with abonormal supination related symptoms or weak/ delayed peroneal reaction times causing inversion sprains. Are you hoping to 'lock' the foot so that it can't over invert?
Also rearfoot posts are not one trick ponies. They will modify COP via sagital plane acceleration - the effect of the material under the heel, stabilise the triplanar effect of a bespoke moulded shell, change GRF at heel strike etc.
I don't have any major problems with what you are selling but feel that your approach lacks any real credibility when compared to published practitioners. This does not mean you are wrong and they are right, but when someone like K Kirby states his argument he usually fully backs it up with references.

Phil

Thanks Phil,

[quote=Phil Wells]Ed
Is this approach a 'cure all'? Don't we need to pronate a bit are are you saying that the soft tissue flexibility will allow this?

Nothing is a "cure all". Yes we do need to pronate some. In fact the question you are really asking is how much and from what position. People have been arguing whether orthoses should be rigid or flexible. The quesiton is misstated. The real quesiton is: If we place a curve piece of plastic (or some other material) on a flat surface, how much vertical force should the plastic exert on the human body. The answer is Newton's third law: For every action there is an equal and opposite reaction. If you want me to tell you how much force the orthotic needs to exert, you must first determine the downward force. This is a function of Body weight, foot flexibility (How much are the ligaments helping?), and momentum (mass x velocity). What we have done, which is NEW, is calibrate each orthoses to deliver an approximately equal and opposite force to the downward force of the human body. This is a patented technology. I would love to go into great depth on how this is accomplished if you like.

The supinator is an interesting dilema. I used to say, don't give orthoses to supinators. After all... do you want to push their arches up more? Then when I experimented with this technology on even the most severe supinators, those with CMT etc. it worked to my surprise. I had to rethink. The supinator has an increased calcaneal inclination angle and increased metatarsal declination angle. They bear most of their weight on the first, fifth and tuberosities of the hee. By going full contact, we increase the surface area and decrease the force per unit area (pressure) redistributing it over the entire plantar surface. Similar to full contact plaster casting for neurotrophic ulcers. Now the most functional orthoses are simultaneously the most accomodative. Sweet.

On the "one trick pony" thing. There is no such thing as a purely frontal plane or sagital plane theory. We all deal with three dimensions but the ankle is primarily a sagital plane lever making sagital plane locking, sorry stiffness, of the foot most important for propulsion.

Publication does not equal correctness. Root, Orien and Weed lectured for 15 yrs. before publishing their text and their theories were not backed up by sound research. They had some amazing observations and I am a huge fan of their work (even if I don't agree with all of it). Kevin's critique of my theory lacks substance. We are now in the process of publishing our research. Look over what we have done and comment on the actual substance please. Keep an open mind and be prepared to shift your paradigm.

Is making an ineffective treatment (rearfoot posting) a little bigger an advance just because it has been published? Craig's work has shown how useless posting is at controlling even frontal plane calcaneal eversion. In fact in some cases (about half) it makes the pronation worse. Lets get into the physics here. I have two biomedical engineers on staff and a full time physicist, two brilliant Chiros and the former chief of PT at Vanderbilt. I have taught my course to the heads of all of the engineering departments at Vanderbilt University and we have beat the math until it bleeds. I have taught at 38 universities and too many medical societies to count. What is NOT new about my work is that it agrees with basic principles of physics and engineering. What is NEW is that it is congruent with your clinical observations.
Thanks,
Ed

Sorry Phil,
I forgot to address the issue of inversion sprians or peroneals. The P Longus changes its function in pronation and supination. Root et al. pointed this out. In pronation the PL is an isometric stabilizer of the first metatarsal and in supination it is an active plantarflexor of the first met. An weak or delayed PL is due to its starting position and function. Placing the foot in greater supination will give the PL back its function and timing. Additionally transferring the forces (and their reactions) medially onto the MLA does in fact decrease the possibility of inversion sprains. Also the supinated foot is more stable further decreasing sprains. As long as this agressive technology is not used in curved lasted, split EVA (anti-pronation) sprains should be reduced. That has been my experience.
Ed

The main deficit found in chronic inversion sprain is a delayed contraction of the peroneus longus at heel strike - way before its isometric contraction. The changing of GRF via heavily inverted orthos may be contra-indicated. Maybe worth thinking about.
My main concern re your orthoses is that may/will stop the functioning of the normal mechanics of the foot - the 3 primary arches and negate the need for intrinsic musculature. The reason we add additions to orthoses at the moment is to allow 'normal' function - medial additions allow the hysteresis, 1st ray additions facilitate 1st ray plantarflexion, 2-4 scoops promote transverse met propulsion etc.
I am interested in the modelling of the ortho to resist GRF. Do you take samples over multiple steps and change the properties of the orthos (thickness etc) for the various forces thru the contact phase?
Any data on knee impulse's using your orthoses?

Cheers

Phil

Question: Is the delayed contration of the PL at heelstrike due to inhibitory reflex associated with the standing posture? If we change standing posture, can we 'retrain' the PL? I think this may be the case. :)

Remember that GRF of posts will have no effect at heel contact because the axis of the STJ crosses the GRF at the point of contact. No distance = no torque = no effect.

Great question about the orthoses stopping the normal function of the foot. A similar argument is used in PT against back bracing. Will a back brace replace the function of the transversus abdominus thus making back injury more likely. Repositioning the foot with a semi flexible device is more like chaning the form a person takes while lifting weights. Lifting with bad form will not necessarily build you up and could cause injury while lifting weights with good form will yield maximum results. There are certainly some muscles that have hypertrophied to attempt to achieve better foot posture... these will return to their normal tonus.

I certainly sweated over this question about increased ankle sprains early on. Our observation however, and that of many hundreds of practitioners is that ankle sprains reduced. Now we were in the unfortunate position of trying to explain something that was counterintuitive. When I first looked at the raw data from the emed studies done on our technology at Georgia State University it helped me understand. Raising the arch shifts pressures medially. When more weight is born by the MLA and less is born on the lateral foot. They found just the opposite however in posted orthoses. Walking along the peak of the roof shifted weight laterally, and more so over time.

I really like your research suggestions. Craig will be doing something like this soon, I understand. I have offered him my technology to test. I am also considering sending him my calibration machine to test. We are now working on a nine pin labview system that gives force curves at multiple points on the plantar surface of the orthoses as an evenly distributed pressure is gradually added over the dorsal surface. Craig got to see this new device work yesterday at my lab. I would love to test our theories against what other labs do and against prefabs. We need to have an orthotic beat prefabs hands down. If we don't all customs will be on the endangered species list.
Ed

Ed,

I have found it interesting that a person with an engineering background, as yourself, has decided to create an foot orthosis product, market it, produce a website, send CDs to hundreds of podiatrists around the US marketing your ideas, but has not yet published one article in a peer-reviewed journal regarding these ideas you have. Don't you think you would garner much more respect for yourself and your ideas if you first did the research, had it published and then layed your techniques out for other podiatrists to see if they also thought your ideas were as good as you say they are?? Of course you may not make as much money that way, but you would not be viewed by intelligent podiatrists as simply being another medical professional that has developed a product, has a financial interest in selling more of that product, and are promoting their ideas in order to sell more of their product.

A true scientist, that values objectivity over financial reward, would not put only positive testimonials on the internet regarding their product. They would feel a strong obligation to also publish or put on the internet the stories of the patients who have not done well with their product or who may have not been able to wear their "Sole Support" insoles. I would suggest that if you consider yourself a scientist first, instead of being the CEO of a company marketing a product first, that you should also put "testimonials" of the patients who have not done well with "Sole Support" insoles, instead of only displaying positive testimonials.

I actually liked some parts of your video presentation, but many parts of it seemed to be self-serving, especially those parts where you suggest that only the orthoses that your company makes are the ones that work properly. I know that you have talked with a few of my good friends, Eric Fuller and Craig Payne, and in doing so, you have associated yourself with some very intelligent and respectful podiatrists. However, I am not as nice and politically correct as they are since I just have a very skeptical nature about people who have financial interest in a product and then go out and pay to have research on their product to "prove" that their product is better than others. At least you don't call your orthoses "The Glaser Orthosis".

By the way, I don't have any financial interest in Precision Intricast, Inc. other than they pay me to be a consultant and write newsletters for them on a monthly basis. And, unlike yourself, I have never made any money on the many techniques and devices (medial heel skive, lateral heel skive, anterior axial radiographic projection, supination resistance test, maximum pronation test, STJ axis location technique, STJ axis locator) that I have invented or coinvented for the benefit of the members of the podiatry profession and their patients. Many of these techniques are in use by podiatrists around the world and I have never made a dime off of them. However, I consider myself a very rich man for being blessed with the opportunity to help so many people in this fashion.

I will enjoy your future comments to Podiatry Arena and look forward to your collaborations with respected researchers (such as Craig Payne) to objectively analyze the mechanical nature of foot orthoses and objectively determine which orthosis designs may work best at optimizing the kinetics and kinematics of gait.

Have a nice day. :)

__________________
Sincerely,

Kevin

**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College

e-mail: kevinakirby@comcast.net

Private Practice:
107 Scripps Drive, Suite 200
Sacramento, CA 95825 USA
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Voice: (916) 925-8111 Fax: (916) 925-8136
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Kevin,
I wish the history of our company were as simple or as easy as you stated in your first paragraph. The product and concepts were first developed for my own patients. I saw so many obviously illogical aspects to the biomechanics that we were taught that I spent 10 yrs. working in my garage experimenting with the orthotics. After 13 yrs in practice, I was asked by a friend and PTwhat I was doing. I agreed to lecture at his clinic. To have some notes to hand out I wrote down my ideas and theories. They liked it so much they asked my to speak regionally.... I was flattered but still not sure how Podiatrists would react to my ideas. When I expressed my views to my colleagues they were universally shot down. The PT clinic asked if I would make some orthoses for their patients. I was too busy in practice so I fixed up my garage, hired some high school kids to help me and started making FO's for just a few clinics. Word spread fast that there was a foot orthotic that worked consistently. I was asked to speak at many clinics and a few podiatrist started to use my product. It was crude and unpolished but incredibly functional. After seeing the positive reaction to my concepts and the technology I decided to give up a very successful solo practice (>500K/yr gross in 1995) and try to pursue my dream of changing the way podiatrist looked at foot biomechanics. I certainly did not do this in the pursuit of riches, as you imply. I took a massive pay cut to less than 1/8 of what I made in practice. In fact today I have still not made what I did in practice. For years I put in 16 hour days. My company grew and within 18 months I had 6 employees and moved into a chicken coop which was so deteriorated that I had to rebuild it myself with used building materials because I couldn't afford anything else. We used rejected mouse pad for walls, rolled insulation over bailing wire for a ceiling and used a portapotty. I started to get better lectures. State societies, universities etc. Some paid me.... most did not. I continued to research my ideas. As soon as I could afford it I co-funded some basic research in Georgia State University. I wanted to test what I had done to see why it was working so well. The company continued to grow at a fantastic rate. Some years we doubled and rarely grew less than 30%. Four years in a row we were named the Future 50 most promising companies in middle TN. Each year since then, as I could afford it, I increased my research spending. We now do research at 6 universities. Most of the projects are basic science to understand foot function better. I also spend some time studying the bones at the Smithsonian Institute. It was a Herculean effort to manage such a quickly growing company, do research, lecture in 65+ cities per year. We brought in students from Vandy to help with the research. We hired the most outstanding student that took the greatest interest in biomechanics. He is now getting his Phd while working part time for us. Then we hired a physicist, machinist, welder, electronics expert and another engineer with a Vandy Masters degree. When you are already growing too fast you don't care about publishing. I felt that we were getting the word out as fast as we could currently grow. It gave us a valve that allowed us to turn on and off the growth so as not to sacrifice service or quality. Meanwhile I was getting feedback from hundreds and now thousands of practitioners which helped me continuously refine the technology. I disagree... an engineer is exactly the person who would NOT publish because the technology is improving so rapidly that by the time it was published... it would already be outdated. Calibration for example was a ten year project that (as Craig has recently seen) is not close to over. I was somewhat modest about my ideas and uncertain how they would be recieved until they were completely proven. I did the DVD after 10 yrs. to preserve the technology in case something happened to me and to protect the livelihood of those that invested their careers into my dream. I recently started writing articles.....which as you know takes 18 months to get published, because I had a medical condition that was life threatening and did not want the ideas to die with me. We now have a 35,000 foot facitliy with real bathrooms and a research building and continue to grow at a scary rate. The demand for my lecture continues to expand and we are also on the cutting edge of 3D medical animation to create teaching tools that are above anything ever produced. Many are in the DVD.... the new ones are even more awesome.
You have done some great things for Podiatry, which I apprecitate. Don't be ashamed that you make money from a lab. You "consult" and write their newsletter. Do you honestly think that they hired you without some marketing intent? Do your newsletters attack their product? Of course not. Testimonials are just that. Of course there are patients and practitioners with complaints as I am sure you also experience. We bend over backwards to make each patient better. In fact that is our one core value, "We Make People Better". You seem to be stuck on the testimonials.... go to downloads, there are hundreds of pages of information about clinical diagnoses, theories, studies, etc. etc. etc. That is the meat... the testimonials were just added recently and are window dressing.
Now the real question.... Why are you attacking me personally instead of my ideas. Give me hard physics reasons why my analysis of rearfoot posting is flawed. Do I need a research project to show that heels are round and so are heel cups. Observe....LOOK. We don't need a double blind study for the obvious. Do I need a study to show that the soft tissue moves over the heel bone.....grab your heel and see for yourself. Do I need a research study to show that F=ma?.... straight ahead Newtonian Physics. Do I need a research project to observe that the STJ axis exits the foot at the point of heel contact. Some practitioners are capeable of observing all of these things without studies. When I do studies it is to improve and refine my technology, not to create a name for myself. NO, I do not call anything the "Glaser" this or that (unlike the Kirby Skive) because this is not about my ego or money.....It's about making people better. I look forward to what I have not seen yet.... substantive criticism.

Thanks,
Ed :)

What does this mean please? When is a joint not "axial"?

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Can't help but notice the low shot at Kevin Kirby regarding his supposedly massive ego in Ed's last post...

I believe the Kirby Skive was originally termed "Medial Heel Skive" by it's inventor, and other podiatrists call it the Kirby Skive to pay respect to the Podiatrist who invented it. I have never once seen Kevin call it the "Kirby skive" :p

Ed I've taken a glance at your website and training DVD. Some interesting statements in both.

I especially liked this one from your hallux abducto valgus newsletter:
"Treatment: The most effective is biomechanical control of arch/first metatarsal position at midstance with Sole Supports orthotics."

In the UK it is customary to provide research data to support claims such as this. I would be interested to hear, as would the National Institute For Clinical Excellence, of the details of randomized controlled trial which enables you to draw this conclusion.

Thanks in advance.

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Ed,
Could you explain how the work of Jan Brukner on STJ facet variation impacts on your theory regarding sequential facet contact transfer?

Thanks in advance.

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Ed, Could you explain how the variable geometry of footwear, terrain and neural imput impact on your theories of impulse/deceleration and concrete surfaces as a cause of pathology?

Thanks in advance.

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