Forefoot Varus Predicts Subtalar Hyperpronation

Here's a few shots of an SMO designed and constructed by the prosthetist/orthotist I treated/interviewed for my pilot study. Notice the full lower leg/foot cast in the background of one of the pics. This is labor intensive, time consuming and expensive. His billing coding is not for a typical orthotic but is much more involved. Notice the carbon graphite shell with the cutout for the 5th met base.

 

https://www.youtube.com/watch?v=aF395Pe4cEk

 

Simon,

Can you explain how you might deal with diagnosing and treating the patient I discussed recently. Say his primary care doctor referred him to you with a chief complaint of pain in the ball of the foot and pain in the medial arch of the right foot. The podiatrist who wrote the Rx for his orthoses wrote metatarsalgia/capsulitis B/L and on my examination he complained of severe pain at the apex of the right arch with palpation of the medial band of the plantar fascia with pain along the entire band but no detectable nodules. He is 59 years old with a history of fasciitis and right knee replacement and has a difficult time ambulating barefoot due to pain in the balls of his feet. He has pain on palpation under the met heads, especially sub second. He has an apropulsive gait and is laterally unstable especially to his right side (several times he had to put his hand on the wall on his right side during his gait analysis to prevent falling or to transfer weight off his right foot while walking barefoot). As I mentioned we have x-rays demonstrating a significantly lower calcaneal inclination angle on in his right foot.

I noticed that you and Kevin had a difference of opinion about the benefit of measuring structural conditions and describing foot types. I'm trying to get a sense of how your approach might differ compared to the podiatrists that I deal with through my lab. I realize this is a hypothetical case for you but I think it would help me better understand how you do things in your practice. If you need additional information I have access the patient if you need me to check on anything else.

Thanks,
Jeff

 

Sure, as soon as you answer my question to you, Jeff.

 

Simon, physicians have this problem every day with every lab test. That's why it is important to remember that we treat patients not lab values. Is a WBC value of 9.9 normal and a value of 10.1 abnormal? Likewise we treat patients, not X-rays. We treat patients, not goniometric values. And so we go. That's the art of medicine, learning where that shifting line is between normal and abnormal.

I think you'll find throughout my all posts a call not to accept the goniometric values that everyone has been taking as being adequate. You'll find my published papers advocating measurements that Root never took. You'll see my adoption of the Kirby techniques of measuring and calculating the STJ axis, combining his techniques with those I also developed. You'll see me publishing additional MTJ measurements and also advocating for the development of others. I have had enough experience to satisfy me that the "Root measurements" are useful, but also to know that it's not enough to figure out everything, let alone get into the real business of prediction. I just reviewed a paper for a journal that could open up some real biomechanics understanding of what happens in gait. I am definitely not satisfied with the status quo. My attitude is that Root started rolling a snowball, advocating a quantitative clinical approach to foot orthopedics, but he never made the full snowman. (My grandchildren here in Florida will never understand that analogy)

Best wishes,
Daryl

 

Simon, I will answer your question above and then you can answer mine about how you would clinically approach the patient I discussed.

I believe that we use biometric data to check for risk and contributing factors. As I recently mentioned, a larger degree of a plantar flexed 1st ray condition is a risk factor for inversion ankle sprains. Whether that individual actually develops inversion ankle sprains is multifactorial. We know that fair skinned individuals are at greater risk for developing skin cancer than darker skinned individuals. Although not all individuals with fair skin develop skin cancer, it is an indicator of greater risk.

My son has a high arch and a plantar flexed 1st ray resulting in an everted forefoot. I never treated him until he started having inversion ankle sprains while playing soccer and baseball. Sports is the only time he had problems associated with his foot type. Had he not played sports and had he chosen to focus his efforts on the piano which he was extremely good at when he was very young, he never would have required treatment. So yes environment/function is a factor and so is foot type.

In the case I discussed, I said he has a very low calcaneal inclination angle (not that it was just lower) on his right side where his plantar fascia symptoms are much worse. This radiographic evidence helps explain why he might have more symptoms in his right plantar fascia since the foot is more pronated in stance and the radiographs show a structural condition that appears to be a contributing factor. He also has a plantar flexed talus relative to the navicular B/L so his midfoot does appear demonstrate reduced structural integrity B/L. I'm curious how you would approach this patient.

Jeff

 

Jeff,

Since you mention my name here, let me tell you how I would treat this patient.

With Tissue Stress Theory, the goal of orthoses is to 1) reduce the stress on the injured tissues, 2) optimize gait function, and 3) prevent other pathologies from occurring, we mainly need to know the exact structures which are injured (Fuller EA, Kirby KA: Subtalar joint equilibrium and tissue stress approach to biomechanical therapy of the foot and lower extremity. In Albert, S. (ed), Lower Extremity Biomechanics: Theory and Practice).

From the patient you describe above, I would first want to know where the subtalar joint (STJ) axis is located in standing to determine how foot orthoses might need to be adjusted to optimize STJ moments during weightbearing activities. From your description above, and without the benefit of me actually being able to examine this patient to determine which exact anatomical structure is injured, I will assume that the medial band of the central component of the plantar aponeurosis is injured along with the lesser metatarsal heads (possibly the plantar plates are injured?) since this is where you describe the symptoms to be. In addition, the "lateral instability" you describe may simply due to him walking on the lateral side of the feet to avoid the pain in the medial arch and medial forefoot.

I would likely design the orthosis using a polypropylene shell with a minimal arch fill and plantar fascial accommodation, a slight medial heel skive (2-3 mm), a 16-18 mm heel cup, a 2-3 mm heel contact point thickness, with the anterior trim line of the orthosis shaped to follow exactly the metatarsal necks (this will make it much longer at the 2nd met neck than normal), and anterior orthosis edge which is 3-5 mm thick, along with a topcover incorporating a forefoot extension of 3 mm korex to help accommodate the most painful metatarsals and try to address any "lateral instability" the patient does have.

I don't need to know where his STJ neutral position is, but would like to know how far from the STJ maximally pronated position he stands. I don't need to know his calcaneal inclination angle, but would want to know where the STJ axis spatial location is during standing. I don't need to know what his "forefoot to rearfoot relationship" is, but I would like to know how "tight" his gastrocnemius-soleus muscle is. I would also be testing his STJ invertors and evertors to try to determine what may be causing his "lateral instability" that you said he has.

Am interested in other's comments on how they might design an orthosis for this patient.

 

Kevin,

I dispensed his orthoses on Friday. We made a Root Lab Cushion-Flex Orthosis using a 3 millimeter HDPE (high density polyethylene) shell with a full EVA bottom fill for shell stability, poured the cast (heel) 4 degrees inverted, 2 millimeter medial heel skive, no medial arch fill, 18 millimeter heel cup, 1/8 inch full length Spenco type top cover, medium depth met pad and 1/16 poron extension to the sulcus.

When I dispensed his devices he said that the left was fine but right felt like a golf ball in the apex of the right medial arch. I ground out some of the EVA and he determined that he could tolerate the device for his initial break in. After adjusting the right, he then asked if I could reduce the EVA on the left, which I did slightly. Today I sent him a message asking how he was doing and he replied "up to three hours, left just fine, right a little sore but getting better". I anticipated it would take a little more time for him to get accustomed to the devices given his foot type.

I did not use a polypropylene device because the doctor asked for a "flexible" shell, neutral position cast and met pads. However, I opted to pour inverted and use the medial heel skive since the Rx was just a note and wasn't specific as to all of the Rx specifications.

Jeff

 

Kevin,

I forgot to mention that he appears maximally pronated and his heel is approximately vertical in stance.

Jeff

 

I might want to know supination resistance and the measurement I call Eric's forefoot measurement ( I forget the offical name)

Not 100% sure of script as it is a bit too hard without knowing more about the ball of the foot pain, but Kevin one of my 1st thoughts was a cuboid notch, would that be something you " would " consider

 

Jeff, thanks for skirting around the question I asked.


In addition to Kevin's reply, I'd also look for capsular/ non-capsular pattern in the MTPJ's, plantar plate provocation test, reverse windlass testing, Jack's test with assessment of stiffness, sit-to-stand navicular drop and drift and a visual gait assessment. Given the recent knee replacement, the feeling of lateral instability and asymmetrical foot function, I'd also check for a limb-length descrepency and alignment of the knee.

Management might be anything from a flat EVA insole with plantar metatarsal deflective padding with/ without met dome and adhesive wedging, or modified prefabricated foot orthoses, or full custom, the design aim of all to reduce the stress in the injured tissues. Without seeing and examining the patient, that's about as detailed an answer as I can provide.

 

I would grind in a plantar fascial accommodation either on the initial visit or on a subsequent visit if the plantar fascia was the source of the arch irritation (which it is 90% of time). Also, I would tend to grind the top of the orthosis plate for the plantar fascial accommodation.

 

Kevin,

When I dorsiflexed his hallux there was virtually no tension in and bowstringing of the plantar fascia. Had it been prominent or tight, I would have accommodated it. He has point tenderness on the right fascia but no nodule. Since the plantar fascia grove reduces contact pressure in the medial arch pressure, and since it wasn't prominent, I didn't see any benefit of accommodation.

Jeff

 

Also, if you've got a very medial STJ axis, you can just have too much compression force in the area of the axis, obviously increasing arch fill may help here (reduces shell curvature = increases shell compliance), increasing the depth of the medial heel skive will work similarly but what I've done successfully in the past when using compliant shell materials is to have a medial oblique rearfoot post made of high density EVA which ends parallel and slightly proximal to the STJ axis and then use a low density EVA from this line and distally as underfill. This way the device is much stiffer on the medial side of the STJ axis than on the lateral and compression beneath the axis should be reduced. You can also add heel lifts which should reduce the forefoot dorsiflexion moment about the medio-lateral MTJ axis. It's just skinning cat's.

 

Maximum eversion height.

 

So, in other words, Simon and I would be evaluating and treating the patient very similarly.

The function of custom foot orthoses is not about "preventing compensation for foot deformities", "making the patient function in subtalar joint neutral position" or about "locking the midtarsal joint", as I, and thousands of podiatrists were taught by the biomechanics professors who were trained by Root and company.

Rather, the function of custom foot orthoses is to 1) reduce the pathologic stresses acting on the injured structural components of the foot and lower extremity so that the patient's pain gets better, 2) optimize the patient's gait function, and 3) prevent new pathologies from occurring in the future. It is called Tissue Stress Theory. It makes good mechanical sense, and it works very well.

 

"Abnormal compensatory pronation of the foot is the most common cause of pathology within the foot (90). An abnormally pronated position of the foot, or the motion of pronation which occurs at the wrong time, causes the foot to become abnormally unstable when the foot is bearing weight. The osseous instability present in a foot exhibiting abnormal compensatory pronation causes hypermobility to develop at the joints of the foot. Hypermobility, in turn causes microtrauma to the soft tissue of the foot with each step. This microtrauma eventually leads to the development of many symptomatic conditions, if the individual continues to use his foot in an average manner". Normal and Abnormal Function of the Foot, page 289.

Is not microtrauma of the soft tissue the exact same thing as "Tissue Stress"? Yes, you can put lipstick on a pig, but it is still a pig!

 

Think I need to put my waders back on...the water's getting REAL deep in here! What a bunch of rubbish. I can't believe the "gurus" are offering such lame answers to seemingly not a difficult case. Sure...there's a lot of info we don't have, but really...who cares where the STJ axis lies with this patient? Just assess the STJ ROM, determine if that patient is functioning at the end of eversion of his right foot, (I would bet that he is, thus the lateral instability), and construct an orthotic that keeps him from maximum eversion, ie., in a more neutral position. Any forefoot deformity also needs to be addressed, otherwise, the patient would not be able to tolerate the rear foot corrected, more inverted position.

But along comes Simon...offering his "expertise" on the subject and the reality is, he's given us nada...zip, zero, nothing. In fact, THE only thing he wrote that makes any sense is his suggestion that a LLD might exist due to the surgery...but other than that? Phenotype vs genotype? Are you kidding me? Bah!

If that patient returns to see Jeff, may I suggest that Jeff ask him why the knee needed to be replaced? My conjecture is that the medial tibial plateau was worn out, causing the pain that no longer responded to hyaluronic/cortisone injections, (hardly ever does, and it's simply a Band-Aid anyway).

Chances are, this patient is headed for a STJ/triple arthrodesis, as the foot may be too "far gone' to offer long term corrections, based on what limited information I have. Don't know...don't have X-Rays of the left and right feet, or the patient in front of me.

I've been doing some thinking on the subject of why there's such a variance of opinion on this board...those with dogmatic positions, while others take a different tact. My conclusion is that perhaps those that are more dogmatic in their approach don't perform surgery. In other words, they don't have "a dog in the hunt". Surgeons take a far different view of patients, because, if and when they have to perform a surgical/corrective surgery, they view their end results differently. They think about the osseous corrections and the effect of gravity...they have to....the patients' well being is at stake just as the surgeons' reputation and avoidance of malpractice lawsuits enter into the equation...ultimately. When was the last time you ever heard of a Podiatrist being sued for an orthotic that wasn't constructed correctly? Podiatrists that perform surgery HAVE to consider ALL options prior to taking the patient into the OR, and have to formulate a game plan on how to treat that patient afterwards, short and long term. There are probably several cases we see everyday where we realize surgical intervention is the best option...those patients that present with extreme valgus positions of the rear foot, secondary to forefoot deformities as an example. I described this very situation in an earlier post where the patient needed a medializing calcaneal osteotomy, a cuboid osteotomy and a modified Hoke procedure with tendoplasty of the Anterior tibilais tendon with the Posterior tibialis tendon placed under a periosteal flap to form an ossified buttress to prevent excessive talar adduction. Not a word from anyone here...not one reply. Interesting...but in my mind, the "silence" was deafening.

 

Just because Dr. Root acknowledged that tissue damage can be caused by microtrauma, doesn't also mean that the anatomical location of the tissue pathology made him want to change his orthosis prescription method away from the STJ neutral/vertical heel/and 3/4 length orthosis design he nearly always advocated for nearly all feet.

Here is what I remember Drs. Mert Root and John Weed teaching us on how to properly order foot orthoses for our patients:

1) Cast in STJ neutral position in all patients unless the foot has a peroneal spasm which then you can cast in STJ maximally pronated position.

2) Balance all positive casts with the heel vertical unless the maximally pronated position of the STJ has the heel inverted or if a peroneal spasm has the foot everted.

3) True "functional foot orthoses" always end at the metatarsal necks. A forefoot extension to accommodate a painful metatarsal makes the otherwise "functional foot orthosis" an "accommodative orthosis" which is somewhat inferior to a true "functional foot orthosis" that ends at the metatarsal necks.

4) Use a rearfoot post in most orthoses and use more rearfoot post motion for patients with low inclination STJ axis and use less rearfoot post motion for patients with a high STJ inclination angle.

And that was about it. Conspicuously absent from Drs. Root or Weed in their lectures on orthoses was any mention about changing the orthosis prescription for posterior tibial tendon pathology, pereoneal tendon pathology, sesamoiditis, medial tibial stress syndrome, patellofemoral syndrome, Achilles tendinitis, or plantar fasciitis, from what I remember.

Jeff, if you can provide us with evidence to the contrary that Dr. Root or Dr. Weed did take into account the anatomical location of an injury (i.e. location of tissue stress) when prescribing orthoses, or wrote anything about how to prescribe proper custom foot orthoses for the multitude of different foot and lower extremity pathologies we use custom foot orthoses to treat, I would gratefully appreciate it.

From what I was taught by the Root Subtalar Neutral Theorists (that taught us all biomechanics at the California College of Podiatric Medicine), if the patient had a calcaneus that "could pronated to vertical", then the patient would be prescribed a STJ neutral, vertically balanced orthosis without a forefoot extension regardless if the patient has peroneal tendinopathy or posterior tibial tendon dysnfuction or medial tibial stress syndrome or patellofemoral syndrome or sesamoiditis.

Maybe Eric Fuller and Steven Gaynor can help me out here in what they remember they were taught at CCPM regarding foot orthosis prescription protocols so we can confirm what all us were really taught at CCPM regarding foot orthosis prescription protocols during the 1980s by Dr. Root, Dr. Weed and the rest of the CCPM Biomechanics Department.

I believe, at this point in the discussion, it might be helpful to revisit Morgan's Meat Pie Paradigm. Morgan's Meat Pie Paradigm really explains what we were taught all too well. For those of you who have not heard of Morgan's Meat Pie Paradigm, this all began about 15 years ago on JISC Podiatry Mailbase (here's a post the JISC Podiatry Mailbase from September 10, 2000....as you can see, we've all been going around round and round this stump for at least the last 15 years:butcher

 

Matt,

I think this is an important point. Most of the podiatrists I deal with use surgical and non-surgical treatment in their practices. As a result, they need classification systems, terminology and examination techniques that can be applied in both areas of practice.

Jeff

 

Kevin,

I will see what I can come up with tomorrow at the lab. I just read an interview with Merton Root that was published in the October 1989 issue of Podiatry Today. I might scan it and upload it tomorrow because I think some of those following this thread will find it gives some insight in Mert's thinking. Here is one question and answer from page 25 of the interview:

Question: Is there a verified normal range of motion in degrees to the midtarsal joint?

Answer: No. I don't believe in normal ranges of motion. I believe that if an individual has adequate range of motion for the functions that individual is using the parts for, that's the normal range of motion. But to say that the average in 100 people is 20 degrees, therefore that's a normal range of motion--this is poppycock.

Jeff :drinks

 

However, I have a problem with the way that structure was classified by Root and colleagues since I feel it left out many important biomechanical factors (i.e. 3D position of talar head relative to plantar foot) and relied too heavily on STJ neutral and heel bisections. Certainly there must be a better way to classify foot structure and "normal" and "abnormal" so we can make more progress in this direction. I believe that maybe we can find some common ground here so we can try and move forward as a profession. (K. Kirby)

Where does it leave us as a profession in South Africa, and other countries where the leaders in the profession is not treining our Podiatrists?

Are there any articles with up to date info on measuring the foot manufacture a moulded orthotic without making use of calcaneal bisection? I still use this method in the lab. From there I add my intrinsic posting (sciving the calcaneal area on the positive cast, medially or laterally as needed).

Currently, my default device is moulded from a positive cast with a calcanal bisection perpendicular to the horizontal. Ye, I know there are many variables and many podiatrists will position the cast differently and all will tell you they placed the cast so that the calcaneal bisection is perpendicular to the horizontal surface of the working area.

What do we work from, or do we eye ball the MLA and decide that the calc position and MLA height is sufficient to relieve my patient from plantar fasciitis. I had success with this also. Is that the reason why orthotis manufacturing is both art and science?

Kind regards

Pierre

 

Kevin,

I believe that what you claim you were taught by Root is called the mechanism of how the orthotic works. On the other hand your "tissue stress" is not the mechanism but the end result. I cannot equate the mechanism with the end result. Funny that by 1980 when I was actually practicing, I was using your three end points as my end-point criteria to evaluate my orthotics, however the end point does not dictate the mechanism. I have to say that we still haven't proved the Root mechanisms to result in these three end points, but the three endpoints will not necessarily give you all the mechanisms.

Just one example - given a patient with chronic ankle sprains due to an abnormal supination torques on the rearfoot complex, how does tissue stress help you determine if the supination torque is due to a plantarflexed first metatarsal or due to an abnormally laterally located subtalar joint axis? How does tissue stress help you decide that you need to support the everted forefoot, with the 5th metatarsal elevated off the ground, or whether you need to create a reverse Kirby skive orthotic?

While I welcome the writings of those who have expounded the biomechanics of the soft tissues, and while I say that understanding these principles assists in the design of orthotics, I cannot just throw away every Root mechanism, with the idea that tissue stress has totally replaced it. I have yet to see that a better orthotic is the end result of this approach.

Thanks,
Daryl

Thanks,
Daryl

 

To answer your question, Daryl, here is an excerpt from the chapter that Eric Fuller and I wrote and that you said that you already read (Fuller EA, Kirby KA: Subtalar joint equilibrium and tissue stress approach to biomechanical therapy of the foot and lower extremity. In Albert SF, Curran SA (eds): Biomechanics of the Lower Extremity: Theory and Practice, Volume 1. Bipedmed, LLC, Denver, 2013, pp. 205-264). Eric and I wrote this chapter in 2004. It wasn't published until 9 years later, in 2013.:craig:

 

Again, Kevin, I read all this in your chapter, and I didn't disagree with any of it, as these were things I was doing in 1980 when there was no stated tissue stress theory. One of the things I remember is that I had some other excellent biomechanical teachers besides Mert and John. One of the most brilliant minds, who became a very good personal friend, was Bud Collins. Pat Laird was also a superior biomechanical mind. Both of these people accepted Root, but they weren't his evangelists, and they had their own thoughts as well. I have mentioned many times before the influence of Milt Wille, and of course there was my own father who was interested in learning all he could from Root, but wasn't afraid to push forward with more ideas. Books of great value in helping me develop in biomechanical theory was "The Biomechanics of Musculskeletal Injury" by Gozna and Harrington, Curwin and Stanish's book "Tendinitis, Its Etiology and Treatment" and Inman's "Human Walking".

After 35 years of practice, in trying so many of the Root ideas and also other ideas and in listening to so many people, and attending nonpodiatric biomechanics conferences, reading the biomechanical literature, etc., there are two basic ideas that I am more convinced than ever that Root was correct about: 1) that there should be a neutral STJ position (we can argue about it's precise location); 2) that the Root Postulate is basically correct (though it may need a little bit of tweaking). Root's acceptance of Manter's MTJ axes is wide open for revision (though I'm not satisfied that Nester has fully solved the problem).

Best wishes,
Daryl

 

This is why Kevin and I came up with virtually the exact same orthotic prescription for the patient I saw even though he advocates the tissue stress approach and I apparently used the "Root theory" approach.

Jeff

 

I don't feel as if we are too far apart in these things, Daryl. Even though we have our disagreements, I do appreciate your knowledge of the literature and your understanding of physics and engineering concepts, since you are a vanishing breed of biomechanically-oriented American podiatrists. There are so few people like you that I always enjoy having these discussions with you and, I hope, when we have these discussions in an open and public forum as we have here on Podiatry Arena, that others can also learn from our debates.

Here in the US podiatric profession, the concentration on surgical solutions for conditions that have relatively easy conservative therapeutic solutions is sometimes bewildering to me. My patients nearly always prefer a conservative solution over a surgical solution. If podiatrists stop offering valuable conservative solutions, such as custom foot orthoses, for foot and lower extremity pathologies, and only can offer surgery, then patients will vote to go to other types of health professionals, rather than podiatrists, for their conservative foot/lower extremity care. The health profession that does offer these conservative therapeutic solutions will then become the leaders in biomechanical care of the foot and lower extremity.

Looking forward to seeing you again in Vancouver in April.:drinks

 

Jeff:

I do believe we came up with very similar orthosis solutions to the patient you described. However, I don't remember Mert Root ever advocating many of the orthosis techniques you said you would use. So, the way you treated your patient with orthoses is not what I learned from Mert Root or John Weed, but seems to me more a modification of their orthosis prescription protocol that actually now takes into account the anatomical location of the injury rather than just the "foot deformity" of the individual.

Jeff, you have learned a great deal since Dr. Root passed. I'm sure your father would be very proud of you and the way you are staying on top of the latest research and ideas and being a leader in the foot orthosis profession. I have always impressed with your knowledge since you probably know more about foot and lower extremity biomechanics and foot orthosis therapy than 95% of all podiatrists.

I do like your idea of providing transcripts of lectures or scanning old articles from Mert Root since most of those following along never had the pleasure and honor of hearing Mert Root lecture or spoke with him personally like Daryl and I have. Providing words "straight from the horse's mouth", would do more to dispel false impressions about your father's work and thoughts than would anything else.:drinks

 

Kevin,

My concern is that those who offer these conservative therapies in the future might have less education and training and diagnostic resources (MRI, radiographs, lab work, etc.) than podiatrists do. How can a CPed know if a patient is better off having conservative therapy or surgery when they lack the medical training necessary to make that determination. Many CPeds are now seeing, examining (or not examining) and directly treating people/customers (you can't call them patients because they are not medical providers). I know there are some very good PT's but the vast majority understandably don't want to invest the time to get an education in and practice foot orthotic therapy the way we, even given or differences of opinion, feel it should be practiced. I think we are rightfully concerned about the future of lower extremity, non-surgical biomechanical therapy.

Jeff

 

Kevin,

I think that one of the big problems we have in discussing Merton Root has to do with time. Like all of us, his beliefs and opinions were evolving. He used the two axis model of the midtarsal joint because he felt it was based on the best evidence at the time and because he felt it was clinically applicable. Last night when you asked me to provide written evidence of his beliefs, opinions and practices I happened to come across an undated letter that he wrote to Daryl Philips. Perhaps Daryl can provide an approximate date. I think this letter provides insight into just how open he was to change.

Jeff

 

Jeff:

Thanks for providing this letter.

Like I said before, information that comes "straight from the horse's mouth", means so much more to many of us than someone else's interpretation of what a person thought. This is the type of first-hand information straight from Dr. Root's mouth or pen that you and Daryl need to make more public if you can. I think it would help change people's image of what Merton Root was all about.

 

Daryl, I'm not quite sure what you mean by mechanism. Do you mean the explanation of how an orthotic works. Root theory has two explanations. There is the supporting of the deformity and there is the pushing the foot towards neutral position. Is the explanation when you push the foot towards neutral position the stress on tissues is reduced? And /or the stress is reduced when the deformity is supported?

The plantar flexed first metatarsal can be the cause of a laterally positioned STJ axis. Medial forefoot pressure can stop the STJ from pronating. If you take two identical feet with the exception of one has a dramatically more plantar flexed first ray. In gait, after lateral forefoot contact, the foot with the more plantar flexed first ray will hit the ground sooner and may stop pronating at the STJ sooner than without the plantar flexed first ray. As the STJ pronates the talus adducts and the STJ axis adducts with the talus. So, the plantar flexed first ray, or any everted forefoot deformity could be the "cause" of the laterally deviated STJ axis. (This is why you should assess STJ axis location in the position the STJ is in, in stance.)

In stance, you cannot separate the forefoot from the rearfoot. Both force on the forefoot and the rearfoot will contribute to the location of the center of pressure. The location of the center of pressure relative to the STJ axis will determine the moment from ground reaction force. So, when there is lateral instability from ground reaction force it has to be because of the location of the STJ axis relative to the location of ground reaction force.

How do you decide if you can support the everted forefoot. The maximum eversion height test. Have the patient stand and ask them to evert. If there is range of motion available you can use an intrinsic forefoot valgus post. If there is no eversion range of motion you have to use a lateral heel skive. The maximum eversion height test is better than measuring forefoot to rearfoot because of the inherent error in forefoot to rearfoot measurement. Even if you could measure forefoot to rearfoot accurately and reproduce heel bisection, you would still have the problem of change in forefoot to rearfoot relationship with change in STJ position. The forefoot to rearfoot measurement will be different when the foot is in stance in a position other than neutral position.

Eric

 

Thanks so much, Jeff.

I do remember receiving this letter, but I don't believe I have a copy of it. Please preserve it for posterity. I believe this letter was received sometime between 1984 and 1986, shortly after I published my first paper on the relationship between the FF and RF. I remember that it was around the time I was living in Vernal, UT. I don't remember if it was before or after I presented to your dad at one of his seminars my idea that the MTJ had 3 nonorthogonal axes of motion, which he was very excited to hear about. As you mentioned he was looking for a better theory of the MTJ than the 2 axis model. Personal discussions with him about his study of 1966 he revealed that while they could reproduce Hicks movements of the STJ, they could not reproduce his MTJ axis motions.

Thanks again,
Daryl

 

"Here is what I remember Drs. Mert Root and John Weed teaching us on how to properly order foot orthoses for our patients:

1) Cast in STJ neutral position in all patients unless the foot has a peroneal spasm which then you can cast in STJ maximally pronated position.

2) Balance all positive casts with the heel vertical unless the maximally pronated position of the STJ has the heel inverted or if a peroneal spasm has the foot everted.

3) True "functional foot orthoses" always end at the metatarsal necks. A forefoot extension to accommodate a painful metatarsal makes the otherwise "functional foot orthosis" an "accommodative orthosis" which is somewhat inferior to a true "functional foot orthosis" that ends at the metatarsal necks.

4) Use a rearfoot post in most orthoses and use more rearfoot post motion for patients with low inclination STJ axis and use less rearfoot post motion for patients with a high STJ inclination angle."

Yes, Kevin, that is what I remembered as well during my time at CCPM when we were classmates. Everyone in our class knew that Kevin would be a leader in biomechanics after he graduated as he was light years ahead of all of us. I give you huge credit for being able to think outside the Dr. Root box and not be programmed as most of us were. I regret not hanging around with you during those years but my main interest was just trying to get decent grades in all my classes.

Regarding orthotic fabrication in school, the only thing I can add is that I was taught (may have been Chris Smith, DPM) to not add plaster between the first and 5th platforms to off-load the tibial sesmoid if it was symptomatic. I was not even taught to apply a top cover on the functional orthotic let alone a forefoot extension as it would make the orthotic less controlling.

I remember being taught that the most important part of the orthotic process is taking an excellent cast with the foot in neutral position and the midtarsal joint maximally pronated. Pour the cast with the heel vertical, balance the forefoot to the rearfoot, apply a mild arch fill and the orthotic should assist in helping the patient's pathology by preventing compensation.

I also recall Dr. Gaines who taught us how to fabricate a Levy Mold (He was in his late 60s and was in practice a long time) sat in on some of the Biomechanics lectures. He listened but did not believe that the Root functional orthotic was a panacea for foot pathology as he in the past had tremendous success with the Levy mold. He was concerned and a bit angry that the Levy mold that was time tested would be discarded forever.

When I went into practice, I used functional orthotics as I was taught to prescribe (and had a great deal of success) but I also prescribed cork and leather full length orthotics made by John Bergman, DPM. I found my patients that were factory workers that had heel pain (or metatarsalgia) found the cork and leather orthotics much more comfortable than the rigid functional orthotics and loved the sponge cushion in the heels as well as the forefoot cushioning.

Great strides have been made in the fabrication of orthotics, but there is no doubt that Merton Root, DPM provided us a solid and well thought out foundation to build upon.

Steven

 

Yep, that pretty much sums up how nearly every single foot orthosis was made at CCPM during my time...we called it Root Biomechanics. No alteration in orthosis design for different pathologies or different deformities, no topcovers, no forefoot extensions, no metatarsal pads, just Rohadur to the metatarsal necks and rearfoot posts....that was suppose to cure just about everything...and when it didn't....you were told by one of the clinicians that you must have taken a bad negative cast... no wonder so many podiatry students had such a bad experience with "biomechanics" and just called it "biomagic" and called foot orthoses "magic shovels"...:sinking:

 

There is no question that much was left to be desired in the biomechanics department at CCPM in the late 70s when I graduated (which persisted into the early 80s it sounds like). After being in the undergraduate teaching arena myself for 10 years, I can now understand a little bit why and be more forgiving. However my experience as a student is that in the CCPM biomechanics clinic no one seemed to be able to cast the foot correctly. After every cast, the clinician in charge would say "you supinated the MTJ", so we would go back and use even more muscle force to pronate the MTJ, feeling like it would take the muscle strength of Arnold Schwarzenegger to pronate that joint. Finally one of my classmates in that particular biomechanics rotation group called up Dr. Root in San Jose and asked if he would like to give us a teaching session in casting, which he agreed to do. There were a dozen of us, including me and Rich Blake who went to the office (Dr. Root still had a key to the office though he had officially retired) and we met about 7PM. He paired us up (I was paired with Rich Blake) and he worked with us, teaching us how to cast a foot using his technique with our eyes closed. Some of the things I learned were 1) the positioning of the patient was the most critical to getting a good cast; 2) you don't have to make a plaster mess on the floor; 3) Root's STJ neutral position was found by feeling the point where there was the least tension on both sides of the joint, i.e. it took equal amounts of force to move the joint in both directions; 4) it took ounces, not pounds, of force to pronate the MTJ to its EROM. Within 4 hours each of us had gained enough skill to make a half-way decent cast of the foot without hardly spilling a drop of plaster on the floor (Root was very particular about not making a mess) Of course I took many more casting lessons from Root over the years post-graduate to refine my technique. I have often reflected on what skill Dr. Root had in teaching in such a short time the casting technique, making it so simple to understand and perform? What was lacking in either the understanding or teaching abilities of the CCPM faculty to teach it?

This experience as a student showed me that the disciples of Root were already misteaching the Root technique. How many other things were they misteaching? I was particularly bothered as a student with the statement that everyone had forefoot valgus. I was bothered by the statement that the calcaneal bisection was parallel to the medial border of the os calcis. That didn't make any sense. As I pointed out - and I realize that my experience was a little bit different than others, of which I'm glad - Chris Smith seemed to be the dogmatic leader of these ideas that bothered me, and he was unwilling to offer any good reasons for his opinions. So it seems that some of my distaste for the style of Chris Smith at that point in time parallels Kevin's distaste for the Mert Root's style of dogmatism. But, again, at this point in my life I can forgive these people for their weaknesses as I become ever more cognizant of my own.

So I scored good grades in the biomechanics part of the CCPM program and thought I was pretty good when I graduated. I had a family of 4 to support at graduation and so couldn't afford to apply for the biomechanics fellowship, so I'll never know if I would have been considered, though the choice of Rich Blake was a good one. However within that first year after graduation I picked up my first biomechanics journal, opened it, and found I couldn't understand a single thing in it. What was wrong? I thought I'd been taught biomechanics by the best (at least I was told by everyone they were the best). So I had to go to my local college bookstore and buy the textbook they were using for Calculus 101-102. I worked every problem in that textbook. (yes I was running a busy practice too) Needless to say I have followed that same pattern to teach myself second year calculus and analytic geometry, linear algebra, differential equations, as well as other subjects that any person who is getting a BS degree in biomechanics would study. Currently I am studying materials science from a college textbook. To say the least, it didn't take me long after graduation to find out that Milt Wille was right, I had been taught all 'bio' and no 'mechanics'. I tried to change some of that during my tenure at Des Moines, but there was no support for this idea from anyone else on the faculty or the associate faculty. Students were told every day by everyone else that they could enjoy a 7 figure income with no knowledge of any math or engineering science. One associate faculty member told me that he only needed the one sentence biomechanics book, "Take a good cast."

In my opinion - and it been such for many years - after Root left CCPM the department coasted on its reputation for many years. As I look at the literature, for many years after Root there were no additional texts and no great research papers that came out of that institution. Root's textbooks were his and his partners' individual efforts, as noted by Jeff earlier. Kevin was the first one that came along that seemed to have a new idea. It is true that Jack Morris brought some good leadership back to the CCPM biomechanics department, and Paul Sherer was a good support. I do appreciate Paul Scherer's fairly recent textbook on pathology specific biomechanical treatments. I also appreciate the efforts of Eric Fuller during his tenure there to make the department more mechanical minded. And of course I do appreciate the efforts of Kevin over the years and his writings and lectures, though I note he still makes his money in private practice. I'm not sure what all the politics have been at CCPM that has seemed to crush the continuing advancement of biomechanics thought and research. Of course politics seems to dominate so many of our schools, including in the last 10 years the departure of Howard Hillstrom from TCPM.

I will agree with Stephen, we certainly need to go back and look at the Levy Mold to try to understand the difference between these two orthotics who can benefit from its use. I can say that if you are going to prescribe an acrylic orthotic, the Root casting technique seems to give the best result a vast majority of the time. I find a few people that can tolerate the Glaser orthotic, but even a great many people cannot tolerate such. For my diabetic neuropathic patients I now use a laminate of soft materials, relying on the material bulk to provide areas of increased force. We call it the Dwyer orthotic. My wife (who is not neuropathic) loves hers much more than her acrylic devices. I have come to appreciate that we were never taught anything in school about soft tissue biomechanics, which is essential to understand in treating the neuropathic foot.

So the future belongs to us, to learn the good and the bad lessons from our own teachers and improve things for the next generation. I hope I still have a few contributions to make myself and hope to inspire others to carry forward, to that promised land where we will be able to predict pathology before it occurs and truly become preventers rather than just managers of pathology. We've got a long way to go, and if we don't change the current paradigm of teaching, none of it will be done by the U.S. podiatric profession. [Yes, there is hope for Simon Spooner ] In my current teaching position in the College of Medicine at the University of Central Florida, I find that the medical students are very interested in biomechanics, much more interested than most podiatry students, and there is disappointment when they find that they cannot apply for a podiatry residency program.

With that said, time to do some real work today, so best wishes,
Daryl

 

Kevin,

What if we were to compare today's automobiles, televisions, computers, telephones, cell phones, imaging technology, aviation, etc. to the late 1950's, 1960's, 1970's and even the early 1980's when you graduated from CCPM? If you were an engineer today would you be criticizing your professors, predecessors and mentors for not having taught you about:

Autos: air bags, seat belts, crumple zones, back up cameras, navigation systems, fuel injected engines, battery powered vehicles, etc.

Televisions: Color, stereo and surround sound, solid state circuitry, LED/LCD screens, flat screens, etc.

Computers: computer chips, RAM, portable computers, the internet, email, CAD/CAM, etc.

Imaging: Ultra sound, computerized tomography, MRI's, etc.

Basically all of these things didn't exist or were not in use at the time my father developed the functional orthotic. It is only natural that we should have progress in terms of orthotic material technology, including shell and covering materials, and in the theories that apply to the use and design of foot orthoses. Let's try to keep things in proper historical perspective. Let's embrace progress, not criticize the predecessors who made that (our) progress possible.

Jeff

 

Yes lets keep things in historical perspective, your father didn't develop the functional orthotic because functional orthotics had been developed and used long before your father's time, Jeff. That's not to say he didn't make changes to functional foot orthoses because he did.

 

Simon,

My father coined the term functional orthotic. He developed the non-weightbearing casting technique for the functional orthotic. He developed the use of Rohadur for the functional orthotic, and used the first semi-rigid material other than steel to the best of my knowledge. He developed intrinsic and extrinsic posting for the functional orthotic. He found methyl methacrylate and used it for posting. If he didn't discover the functional orthotic, then who did? Where in the literature is the term functional orthotic used prior to Root?

Jeff

 

Edit: Jeff changed the text of his original post after I responded (this wasn't cross-posting since Jeff had replied to my response and I to his subsequent response after that before the change was made- bad form, Jeff), originally he had claimed that his father invented the functional foot orthotic, non-weightbearing casting, orthotic posting and the use of acrylics. The following response by me was made in the context of the original claims, he challenged me to dispute these claims which I did below:


Jeff, all foot orthoses are functional, you can go back to Whitman R.: A study of the weak foot, with reference to its causes, its diagnosis, and its cure; with an analysis of a thousand cases of so-called flat-foot. J Bone Joint Surg Am. 1896;s-1-8:42–77, for one of the earliest examples.

Non-weightbearing casting? Try Reed E.N.: A simple method for making plaster casts of feet. The Journal of Bone & Joint Surgery. *1933; 17:1007*

Posting? The concept was clearly no stranger to Wienerman in 1953, although he called this "balancing".

Was methyl methacrylate lost? I seem to recall your father giving the credit to John Weed and Tom Sgarlato for the idea of dental acrylic rearfoot posts in one of his later papers?