Investigation of the podiatric model of foot biomechanics

Simon Spooner PhD, BSc, Podiatrist in clinical practice - hobbies: peeling babies and rolling them in salt.

Master Chef, Plymouth style simon?

 

Eric, I agree 100% with your approach. Each of the Root hypostheses and postulates have to be torn apart to see if they need to be accepted, discarded or modified. When we find something that looks like it should be discarded, we need to also look for ways in which an agreement could be reached between the two opposing views. An example is Nestor pointing that in CKC, there is only one measureable MTJ axis, however in OKC there are multiple degrees of freedom in the MTJ. When Nestor published, immediately a cry went out, "Sink the Root Battleship" from those who want desperately want to see anything possible discredit Root. It doesn't take any great mathematical genius to figure out that the CKC uniaxial model and the OKC multiaxial model can coexist. It is also important that we living today not get too puffed up in our "science" to the point that we cannot be as critical of our own methodologies as we are of Root.

I do agree with your things we need to accept, so I didn't quote them. In regards to the things we need to discard, I would offer the following thoughts before we totally trash them:

1. I do agree with you that Root did not define the EROM of the MTJ. This is just one example of why I refer to the Root volume I book as a concept book and not a true technique book. Unfortunately, none of the research that has been produced since (most of it in nonpodiatric journals) does even a poorer job than Root in this regard. I am still looking for the inexpensive technology that would allow me to work on the problem. In order for us to develop a truly reliable forefoot to rearfoot measuring technique, we have to be able to fully measure the force we place on the forefoot. So the fact that the best published intertester reliability is as good as it is, in the face of terrible instrumentation and lack of well defined technique is great.

As to your comment about what to do with the first ray, that is again an undefined aspect. Current measurement techniques with the patient prone may give different results than NWB casting technique because in prone, gravity will not have a plantarflexing effect on the first ray, whereas in supine casting there is a passive plantarflexion of the first ray, though no one has defined how much. It is different for different patients.

Both of these reasons are not reasons to totally discard forefoot to rearfoot assessments, though we do need to better define what we are measuring and why. You did note that forefoot valgus has to be supported. So that means that you are assessing and documenting it in some way. Does forefoot to rearfoot relationship change? My experience is absolutely.

2. You talk about discarding neutral position. I would say that we need to better define why we consider this important. I have mentioned one reason for even having a neutral position is so that we can use the word "supinated" and "pronated" to denote position. It's like having a number called "zero". Try to express any number without the number of zero -- without it there is no quantity. In today's medical practice paradigm, the more you can quantitate, the better, both medico-legally as well as for reimbursement possibilities.

As I have mentioned before, when I was student, I took personal casting lessons from Mert Root. In analyzing that experience, I realize that the Root neutral STJ position was based very much on a tissue-stress model. He taught that you needed to find the STJ neutral position with one's eyes closed, from a totally tactile sensitivity. He described the feeling of moving the STJ through its ROM as moving down a hill and back up, with neutral position at the bottom of the hill. I am convinced that what Mert was feeing was the tissue tension on the medial and lateral sides of the joint, and that what he described as neutral was that position in which the passive tension on the medial side of the joint equaled the passive tension on the lateral side of the joint.

I utilized this Root technique for finding STJ neutral in my 1983 publication. While I did publish the complete STJ ROM, neutral position and as well as the forefoot to rearfoot data, I did not discuss the STJ ROM data in the paper. You will notice, if you look at it, that there were all types of ratios of supination to pronation from neutral, however at the bottom average, the average was a 2:1 ratio of supination to pronation from neutral.

Root never said that every person should function around their neutral position, nor that the average asymptomatic person does function around this position. He said that the ideal foot should function around this position. Lovett and Cotton said that it was only the fully pronated foot that would be symptomatic. The problem with using EROM pronation as our "zero" point is that we have difficulty in defining what would be a supinated foot. We could use the Wright-Desai definition (which they published one month AFTER Root's publication of "An Approach to Foot Orthopedics"), using the heel vertical definition of neutral then negates the concept of partially compensated rearfoot varus - which you feel is a valid condition. So those who totally discard the Root idea of neutral, need to better define another point between the two EROM that we can say the foot is neither pronated nor supinated. I find that the people who throw out neutral position idea don't have anything to replace it with. We can talk all about kinetics being the real issue, however having a Root neutral position makes kinetic discussions even more clinically applicable. I could launch into a material property discussion on how the shape of the orthotic is so important in creating the supination-pronation moments around the joints on which that we want to change angular accelerations. Those who are preaching the "don't do anything before you have a clinical research paper to prove you're doing the right thing" philosophy are not in the trenches day in and out with patient's asking them, "What are you going to do about my foot pain?"


While you didn't address the issue of "podiatric biomechanics," others within this blog have had "podiatric-derisive" comments. I too was trained in a very limited arena where I had a very myopic view of what constituted biomechanics. One of my first wake-up experiences was attending my first ASB meeting. I found out my biomechanics experience and knowledge was indeed extremely limited. However, after being a member of ASB for over 20 years, I have no problems saying that indeed podiatric biomechanics should be all biomechanical principles that we, as podiatrists, should be utilizing to treat mechanical abnormalities. Today I am as much embarrassed about the term "podiatric biomechanics" as I am about the term "podiatric medicine". If anyone uses the latter term, they should have no problems with using the first term. If any are embarrassed by the term "podiatric medicine", I think that you should get a totally different degree.

With best wishes,
Daryl

 

Simon,

Evidently you do not have Root's first publication: Root, Merton L. "An Approach to Foot Orthopedics" Journal of the American Podiatry Association, February 1964.

I would encourage you to read this essay and then make comments about the points he makes. You will notice from his comments that he was already teaching many of the concepts you mentioned. Also, as Jeff and Kevin have already pointed out, Sgarlato (who was a practice partner of Root and Weed at the time) published the Compendium, much of which were Root's class notes, along with other articles. Also Hlavac was taught by Root, so if you read him, you're really reading Root. Interesting that Hlavac's foot radiographic study reproduced Lovett and Cotton's findings (which I already quoted).

I think it's important that you not try to judge Root by your 2013 publication criteria. As Jeff pointed out well, Mert saw the handwriting on the wall, i.e. podiatry had to get on the biomechanics bandwagon. His teaching style tended to be pedagogical, which was the accepted method of his time. Kevin pointed out well that this intimidated many, especially those who were in close proximity to him.

Root never claimed to invent the language. Before Root (and instead in many orthopedic texts today) 'forefoot varus' was synonymous with metatarsus adductus. I find the current use of 'forefoot varus' to have been first used by Perkins in 1948. (yes it first occurred in Proceedings of the Royal Society) I don't find forefoot valgus utilized in the literature before Root. Nevertheless, the most important thing that Root DID do was try to standardize the language so we could communicate. And he tried to get us thinking in terms of closed kinetic chain, not open chain embryological positions that did not . Imagine the difference in surgical correction for a traditional forefoot varus deformity vs. a Root (or Perkins) defined forefoot varus deformity.

I have often pointed out Root didn't have a lot of NEW totally unique ideas. His STJ neutral position idea may be thought of as new because he had not read Lovett and Cotton, and no one since those two had published anything. His MTJ fully pronated idea was indeed totally unique that led to a whole new way of making orthotics.

I think that Jeff and Kevin have fairly characterized the times of Mert Root. Mert was not a PhD, he was a clinician and then an educator. As a result his main emphasis was on developing clinical methods and in building a biomechanics curriculum and mentality. I also have some perspective because I observed my father's fight to be accepted by an exclusionary medical community. Suddenly patients who had chondromalacia patellae were going back to their orthopedists saying the lowly foot doctor had solved the knee problem that the orthopedists wanted to do surgery on. How did my father get the idea to put a piece of plastic inside the shoe to solve a knee problem. He didn't read it in any peer-reviewed journal. All the traditionally "educated people" completely poo-pooed such an idea and wrote it off as "witches brew." However it was Mert and his peers and students that tried to work out theoretically how such was a reasonable clinical thing to do, and they were bold enough to teach it.

Again I believe that the moving forward for biomechanics is not just a "toss-or-accept" dichotomy, but involves being critical of both the original idea as well as of those who have both supported and those who have contradicted it.

Until later,
Daryl

 

Here it is, Daryl.

 

We have been around so many of these stumps before that I really cannot be bothered to yet again (unless you plead with me, which from my track record is not likely) point out the lack of reproducibilities, lack of scientific validities, the glaring tautologies and the laughable assumptions that have muddied what was (is) in fact, a clinically useful paradigm.

What the hell! As of today I no longer a registered podiatrist (no, I was not struck off - I resigned). I await with interest to see whether the emporer with no clothes is still walking the corridors of podiatry arena in the years to come. Right now I have far more important things to do; in my new life at my new address, I live next to Wolf Blass. It is critical that us retirees support the local primary industry. Rob

 

Maybe they used one of these? https://docs.google.com/viewer?url=patentimages.storage.googleapis.com/pdfs/US2645025.pdf

Or one of these: http://www.google.co.uk/patents?hl=...ro h.h.&printsec=abstract#v=onepage&q&f=false
discussed here: http://www.podiatry-arena.com/podiatry-forum/showthread.php?t=60501 Note the calibration for measuring "Achilles Deviation" AKA: relaxed calcaneal stance position". Also that to measure navicular drift.

Perhaps, they were using the 12 criteria which characterise the "normal foot" defined by G.T. Stafford in 1928? I've just ordered a copy of his book, so I'll be able to tell you what those criteria were when it arrives. Certainly Phelps and Kiphuth were evaluating rearfoot angulation in 1932 as noted by Clarke H.H. (1933): "Phelps and Kiphuth lay great stress on the line of the heel cord, believing that flattening of the longitudinal arch always accompanies pronation of the foot. If this line is perpendicular and bisects the middle of the heel then pronation is not present to any important degree. The degree of pronation may be judged by the curve of the heel cord inward. The fluoroscope has been used by some, but this type of examination does not seem practical from the standpoint of the physical educator".

Oh, and as an aside this appears to be a contact digitiser from 1924
https://docs.google.com/viewer?url=patentimages.storage.googleapis.com/pdfs/US1496946.pdf

Here's a reference to forefoot valgus I posted previously from 1951- "There was a slight valgus deformity of the forefoot in two cases" A.J. Drew 1951 http://www.bjj.boneandjoint.org.uk/c....full.pdf html

All of which is interesting, but today is the 9th of November 2013. All publications should be viewed against the knowledge we have as of today. I'll ask again, perhaps someone could point me to the scientifc research which has demonstrated the validity of the Rootian model so that we may evaluate it through the scientific eyes of 2013, rather than through the rose-tinted spectacles of 1960's San Francisco?

 

que up the mamas and papas
http://www.youtube.com/watch?v=N5AdzVQkrsU

 

Rob,

Simon asked : “What I would ask is exactly what was it that Root was the first to describe”? Kevin replied with a list of seven items and then said “I have contacted Jeff Root, Daryl Phillips and Eric Lee to see if they agree with me or if they have any further suggestions”. Out of respect for Kevin who sent me a private email to alert me to his request, I took the time to make a partial list of some of the concepts and osseous conditions that came out of Dr. Root’s neutral position system of classification. It was not my desire or intent to get dragged into another Podiatry Area debate about the validity and clinical value of the system since we have had that discussion numerous times before.

What you and others on the Podiatry Area fail to acknowledge is that this system is successfully used for clinical intervention throughout the world on a daily basis. While we all recognize that it is not a perfect system, I believe it is those who refuse to acknowledge the benefit of this system who live in denial, not those who use it in spite of its imperfections. Navigation by satellite technology (GPS) is far better than navigation by the stars, but if you are lost in the woods and all you have is the stars, you use what you have. Biomechanics is still at the lost in the woods stage.

Because I own a prescription foot orthotic laboratory and because I have clients who are attempting to relieve mechanically related pathology on a daily basis, I must have some means of communicating with my clients about methods of treatment. I don’t have the luxury of waiting for academia to try to prove what doesn’t work while offering nothing in return that does. My needs are immediate. A recent example of the implementation of Root’s system was for a patient with a skew foot. The patient lacked a range of calcaneal eversion that would bring the heel to vertical and had a partially compensated forefoot varus. He is unable to bring the medial aspect of the forefoot to the ground to properly load the 1st ray and hallux. We manufactured an orthosis with an extrinsic forefoot post of six degrees (bringing the heel of the cast/foot to six degrees inverted) and added a six degree varus (inverted) forefoot extension that went out to the end of the toes. The patient is impressed at how effective the devices are.

The patient I just described happens to be a Certified Prosthetist and Orthotist here in California. According to the podiatrist who is treating him, he is amazed at the poor quality of orthoses that he sees being dispensed by podiatrists in his area. I'm sure that most if not all of them claim to be using "Root" theory but the reality is many podiatrists do not do an adequate job of it. The problem is often in the implementation, not in the theory itself. This gentleman dispenses over 1500 pair of orthoses per year in his own practice and has learned a lot through the quality care he recently received by his podiatrist.

My constructive question to you is, what alternative system do I have that will enable me to communicate effectively with my podiatric clients and will help us achieve superior outcomes to those we get using our current system?

Thank you,
Jeff

 

Simon,

Please save us the time. Just point us to the research that clearly demonstrates the most effective system of prescription foot orthotic therapy so we have the luxury of changing to the new system! Given all the evidence, there surely must be several books that clearly tell podiatrists and prescription foot orthotic laboratory owners like me how to utilize the new evidence (systems) in clinical practice. There are several books on functional foot orthotic therapy via the Root system. Which of all these excellent modern day researches has published a book describing modern day foot orthotic therapy based on the new evidence? Are these books being used as text books in the podiatry schools? Where do we find them?

Thanks,
Jeff

 

Sorry Jeff, you are attempting to shift the burden of proof. The moot point being that there is no validity to Rootian theory, not "is there another theory?". I can list many, many scientific studies which question the reliability and/ or validity of Rootian theory, the PhD thesis at the top of this thread being just one of many. Are you saying that you cannot list any scientific studies which appear to support the validitiy of your Dad's theories?

 

For those who are interested, some time back I took a picture of the forefoot measuring device that Dr. Root developed and used in his practice and I posted it on PM News: http://www.podiatrym.com/pmnewsissues.cfm?pubdate=08/21/2010. These were once very popular biomechanical tools and are the most accurate tool for measuring forefoot to rearfoot relationship. The window is placed over the heel bisection and the front section is extended and placed parallel to the plane of the met heads while the stj is held in the neutral position and while the mtj is held fully pronated. The pointer then indicates the degree of forefoot inversion or forefoot eversion present in the foot. PM News incorrectly labeled my picture as “Bikefoot Forefoot Measuring Device”. Here is a link to the Bikefit tool which as I said on PM News, could be modified to create a Root type forefoot measuring device: http://www.bikefittingtools.com/index.php?page=forefoot-measuring-device-ffmd. Can anyone tell me if Root’s own device has ever actually been used in any study that attempted to validate his forefoot to rearfoot measurement technique? As Dr. Root wrote in his book, the device is initially awkward to use and requires some practice, so it would require some initial instruction and practice prior to testing. I use it!

Jeff

 

I tested it's reliability as part of the pilot study for my PhD as I was thinking of using it for my measurements within my PhD, I found it woefully unreliable in my hands. Perhaps because I only had two hands, unlike the three that were obviously needed to operate this device.:dizzy: Reliability issues aside, the biggest problem lies in terms of validity, the instrument attempts to make inferences with regard to the position of the talo-navicular joint and calcaneocuboid joints, yet ignores all of the other joints twixt the two measurement reference points i.e. the heel and the forefoot, there's only a further 10 articulations between these two reference points!

One of my PhD supervisors Dr. Tim Kilmartin chopped one up, since he thought they were woeful too, to make a prototype of his sagittal raynger. I've stil got his prototype in my desk at work.

 

Of course I'm shifting the burden of proof. You're asking me to use a more scientifically valid system and I'm asking to know just exactly what that system is? Or are you asking me to abandon my system in place of nothing. You can just go on using your flawed system and I can go on using my flawed system, since without what I'm asking for of you, it's just a matter of personal preference. Another option is I will use the Root theory knowing it has flaws and you can choose to use nothing and do nothing knowing that any system you choose would be flawed.

Thanks,
Jeff

 

It was designed for two hands and that's what was shown in the book.

 

Nope, that's a straw-man, I'm not asking you to use any system. I'm asking for any published scientifc study which validates Root's theories. Clearly you cannot provide any. Can you state for the record that there are no scientific studies that validate the theories of Root? Perhaps then we can look at modern science...

Here's a model of clinical practice: "The tissue stress approach to biomechanics"- critically evaluate the literature regarding this model...

 

Maybe next week I can post a very short video demonstrating just how easy it is for an experienced user to use it.

Jeff

 

Perhaps next week you could also post the results of a validity study and a between day-interobserver error study? Yet I doubt it.

 

A tad out of my depth, but here goes; I can`t debate with the likes of those who have had the privilege and experience of being taught by Dr Root (long before my time as a podiatry student), nor do I have the expertise that scientists such as Dr Spooner and Professor Nester have in researching the history and modern day application of foot orthoses and biomechanical models. I do agree that we should acknowledge Dr Roots` work as definitive at that time, that is; forty/forty-five years ago.

However, I can speak of what kinematic studies can inform us of as practitioners today. Correct me if I am wrong (and I probably am) but I was under the impression that Dr Roots` work was based on static examination only of the foot and ankle (predominately, with the STJ influencing other joints/segments) made with the assumption that this is how the foot behaves in dynamic gait and that structural deviation from this `normal` foot results in predictable compensations/pathology. Thus, an `ideal` foot structure exists and all orthoses should be designed to achieve this `norm`.

Scientifically, we can only implement knowledge once theory is validated, which requires testing real world experience/observation with appropriate experiments. We then interpret results against said theory and, if required, re-write/adjust our theory based on this scientific evidence. Chris Nesters dynamic studies, in particular, do this and demonstrates that clinical practice is about recognising person specific features of foot biomechanics, not a one-stop-shop based on an` ideal` or `normal` foot structure and function.

As a relatively recent podiatry graduate, the take-home message from uni was; podiatric biomechanics and/or orthoses prescription is not about making every foot behave the same way. It IS about addressing person/pathology specific requirements by interpreting clinical assessments/features of the clinical signs and symptoms in context of scientific evidence.

In summary, we were taught that “foot posture, position and pressure distribution measured statically do not reflect foot position, motion and loading dynamically” – Nester 2013, BSS

Cheers,
Bel

 

If people have no interest in obtaining the proper tools and in learning how to use them, then how can you possibly conduct a between day-interobserver error study?

 

Those that have watched my life know that there are essentially two parts to it. 1) Podiatric Biomechanics (whatever that is), and 2) Palaeoanthropology. In the second half, I have been dealing with Creationist nutters for many years - you will be aware of this. Sadly, as I withdraw from the Podiatric world, I see the same non-cogent arguments that try to support the Root Pradigm. I am faced with the Root Creationists. Don't laugh, its not funny, but it is true.

In the Science - Creationist world, we ignored their rubbish, thinking the the rest of the world world agree. When we found, to our chagrin, that people could be persuaded to believe rubbish, it was clear that the only way to deal with this was to fight back. Google "Creationist - science" and you will find all you need to know. The minute hard science comes out, they start to correct minor spelling and punctuation errors in our work - been there - done that, recently on this arena.

The sad thing to me, as a a slowly retiring lecturer of anatomy and podiatry students is that I am seeing the same in the pod world. We now need to deal with Root Creationists..........

I am too old to argue, I am too old to be bothered to answer questions like: "provide me with better". If something is wrong, then it is wrong; no amount of words will make it right. I started looking at this stuff when I was 24; I am now 58. The world has moved on hugely - that was pre-silicon chip for Gods sake. But yet we are still expected to think that a calc bisection line of zero validity in any sense of the word has some function.

Well, to misquote one of my recent critiques: I had best get me trowel. Rob

 

If the practice of any branch of medicine were a pure science, then I could accept your point. However, the clinical application of medicine is both science and art. And in the absence of hard evidence to direct us to the ideal or best treatment, the clinician must subscribe to theory and employ the clinical application of theory in order to provide some form of treatment for today's patient.

Root theory, or more specifically his neutral position classification system is utilized in a variety of ways by thousands of different practitioners. Some are more successful than others. One definition of reliable is "Yielding the same or compatible results in different clinical experiments or statistical trials". There is an expression which says close is good enough in horseshoes and hand grenades. The better practitioners of clinical biomechanics get close, and for now that is the best they can do. The clinical benefits of prescription foot orthotic therapy are well documented, and many of those cases involve some aspect of Root theory. Unlike your religion analogy, one can acknowledge the flaws and imperfections of the system while at the same time use it to the best of their ability for clinical intervention until a better alternative comes along. That is precisely why the practice of Root theory and functional foot orthotic therapy has changed and evolved over time.

Jeff

 

At lectures podiatrists would often come up and tell my father that they were a disciple of his. My father told me how much that comment bothered him because as he said “I want to inspire others to think, not to follow”. For the remainder of his life, my father remained openly disappointed about the lack of progress in lower extremity biomechanics and would have embraced new evidence and better science in the field. He remained was one of his and the professions harshest critics.

Jeff

 

Root's method of evaluating each and every patient involved
1. Taking a good history
2. Conducting a range of motion study (ankle, 1st ray, hallux, stj, mtj, knee, hip, etc.)
3. Taking static biomechanical measurements including RCSP, NCSP, ff to rf relationship.
4. X-ray evaluation (was routine at the time)
5. Conducting a comprehensive gait analysis
6. Might involve blood work or other outside diagnostic services
6. Correlating all of the above to determine the cause of pathology and to determine the best way to treat it, be it surgically, non-surgically or both.

It is a common misconception that the goal of orthotic therapy is to cause feet to function like the ideal foot. The purposes is to reduce pathological forces. If a patient has a forefoot valgus and a rearfoot varus, you can't eliminate these osseous conditions. However, with the benefit of a functional orthosis, you can attempt to alter how that foot functions in an effort to reduce the pathological influence of said conditions. That is the essence of functional foot orthotic therapy.

Jeff

 

Thanks for the concise reply, Jeff and the correction in my thinking with regard to the `ideal foot`. As I stated earlier, your father should not be discredited for his work and contributions to the podiatry world.

However, with regard to points 2 & 3, namely; descriptive terms for range of motion of joints and static measurements, as students we found these to be incredibly subjective from one practitioner to another and neither test could determine dynamic foot function. Nor could they assist us in examining forces or (more importantly) inform a treatment plan to `reduce pathological forces`. I do agree that foot orthoses can alter how the foot `functions`, but the forefoot/rearfoot relationship may not even play a role in pathological influence, hence the requirement to identify person/pathology specific features of foot biomechanics.

Whilst I can appreciate Dr Roots` neutral position classification system may be useful as reference points to describe a foot-type, as a practitioner I find it lacking clinical value as a predictive tool for prognosis, or pathology. This is because it does not identify state or stage of disease process, nor the tissues influenced by pathology, much like other classification systems of foot biomechanics, for example; the Foot Posture Index.

Hope that makes sense.

Cheers,
Bel

 

Actually some if not all of these do influence dynamic function. We can differentiate an osseous equinus from a soft tissue equinus. The influence of equnius on forefoot pressure is well documented. A TAL can be performed to reduce forefoot pressure. This is why we check ankle joint rom. Compensatory gait changes associated with equinus (often increased stj pronation) can be addressed by mechanical intervention targeted at equinus. The same is true for hallux limitus and hallux rigidus. The same Root type clinical evaluation techniques that are used for orthotic therapy often serve as the basis in making surgical treatment decisions and for determining the most appropriate type surgery. Calcaneal procedures, including radical osteotomies are based on rom and position of the calcaneus. I could go on and on with examples.

My point is, those who make a blanket statement that static measurements are not a predictor of dynamic function are flat out wrong. There certainly is or can be a correlation and this correlation is used in surgical and non-surgical treatment intervention. Fuse the talonavicular joint, the 1st mpj or put an implant in the sinus tarsi of the stj and tell me that these rom altering procedures can't influence dynamic function. It works both ways. ROM can predict dynamic function and dynamic function can be predictably altered by influencing rom surgically and non-surgically.

Jeff

 

Jeff,

I wasn`t questioning whether surgical or non-surgical intervention influences dynamic function. Of course they do.

I would like to see the scientific evidence for your assertion that

as that is not what professor Nester`s studies suggest.

 

Not that I'm suggesting anyone is doing this, but could I suggest that in order to remove personal bias and potential confrontation that may not be entirely helpful to furthering the discussion, you might all want to refrain from referencing any particular author or clinician from the discussion?

Has anyone read the PhD mentioned at the beginning of this thread? Does it essentially just say that the static measurements did not reflect the dynamic exam? What does this mean for clinical practice? What were the different types of static exams used and who did them and how repeatable were they? Which particular 'six segment model' was used and how did they verify it's validity? I assume you take the two methods of measuring something (in this case a static and a dynamic exam), look at how repeatable, etc... each one is in your/ your co-worker's hands and then compare one to see if it reflects the other? How good is this six segment model and what does it really tell us? What relevance is this clinically? How does it effect my practice when I look at feet tomorrow and have to treat a patient in pain?

One of the great things about some of the 'traditional' methods of assessing the foot clinically (static exam) is that it's easy to do in your clinic/ office and easy to offer treatment based on your findings. This is not to say that the exam correctly predicts how the foot functions dynamically. Given my relatively poor knowledge of university-based biomechanics, I assume that my assumptions from doing the static exam are incorrect when I translate them into a treatment for my patient in pain - but the treatment I come up with works (9/10) for other reasons that I do not fully appreciate?

Since people have been sticking shiny balls to feet, what advances have there been in treating foot and ankle pathology? Is the goal of the research to provide a more detailed account of how the foot works to improve clinical practice, or is this PhD just 'Root bashing' (feel free to quote me on that phrase - especially my Australian counterparts )?

 

It's a Good Point Well Put, Bob. However, I`d like to point out that I was not intending to be confrontational by any means, just relating my clinical experiences/research as a student and practitioner.....I`ll stick to skin in future.

 

Sorry Bel,
I wasn't specifically aiming my comments at you (I just replied to the last post on the thread due to my technical ineptitude). Earlier on in the thread Dr's Kirby and Spooner started bowing out. Personally, I rely on people like them to help explain a lot of the relevance of biomechanics writing to my simple clinical brain. One of the advantages of proponents of static clinical exams is that they generally are clinicians with a wealthy of knowledge and experience who have the ability to communicate their ideas effectively in the context of clinical relevance (even if they are wrong). What I'd like to hear is what's right and what and why it matters?
Thanks,
Bob

 

None taken, Bob. You really did make a valid point.

Yeah, Me tu brute. Thus, my decision to stick to discussing dermy stuff henceforth.

 

Bel,

You were questioning/challenging my status quo and I was questioning/challenging your status quo. That is ground for healthy debate. You should never feel reluctant stand up for your beliefs and I certainly have taken no personal offense by your position or from your comments even if my tone may appear to reflect some of my frustration with the unavoidable nature of these types of discussions.

What I'm asking you to do is to look at the logic related to your position and my position. I think evidence is important but we should not kid ourselves into pretending that there is always compelling evidence to support one form of mechanical intervention over another. However, when we apply logical reasoning some of what we see clinically makes sense in spite of the "evidence".

You say that static measurements are not a good predictor of dynamic function. Lets look at the practical application of biomechanics and see how it fits in with the evidence. A patient presents with an increasingly painful lesion sub 2nd and I want to treat it. I do my standard bio eval and find nothing remarkable except for the rom of the 1st ray. I find open chain examination that the patient has a perpendicular ff to rf relationship but the 1st met appears elevated to the 2nd. I examine the rom of the 1st ray and I get 10 mm of dorsiflexion of the 1st relative to the 2nd and 2mm of plantarflexion relative to the 2nd. Has my examine indicate the potential cause of the sub 2nd lesion?

Another patient presents who is eight months post op and is also complaining of a painful sub 2nd lesion. Patient #2 had Lapidus procedure to correct a bunion and says the lesion developed after the recent surgery, which was performed by another practitioner. I do my standard bio eval and find nothing remarkable except for the rom of the 1st met. I again find that I get 10 mm of dorsiflexion of the 1st relative to the 2nd and 2mm of plantarflexion. Has my examine indicate the potential cause of the sub 2nd lesion?

If I did not examine the rom of the 1st ray, how else might I be able to clinically evaluate both of these feet in an attempt to determine the etiology of these sub second lesions for patient's with different histories? Do you see a flaw in the logic of my approach and if so, what does the evidence say about my approach? How would you approach these two cases?

Thanks,
Jeff

 

I believe we have discussed the issue of whether taking biomechanical measurements is important or not before on another thread here on Podiatry Arena. However, with the renewed interest in this thread being expressed by Bel and Bob, there are probably others following along who may want to hear some more thoughts on this subject.

Personally, I believe my training in the biomechanical measurements proposed by Root and colleagues by the Biomechanics Professors at the California College of Podiatric Medicine has made me a much better clinician than I would have been without this training. The segmental lower extremity biomechanical evaluation, when done correctly and when done time after time on a wide range of individuals, gives the clinician the ability to detect subtle inter-individual differences between the structure of the foot and lower extremity from one individual to another.

However, do the measurements advocated by Root and colleagues help predict the motion of the rearfoot during gait? No. But I do think they help the clinician detect structural differences between feet and lower extremities of patients that would otherwise go undetected by clinicians who do not perform these measurements. And for me, as a clinician, the better my clinical skills, the better I feel that I will be at helping my patients heal from their foot and lower extremity pathologies.

Therefore, regardless of what the available research says, and regardless of the opinions of other researchers and other clinicians, I still find that doing some of the biomechanical measurements as advocated by Root et al is important in helping me to understand the structure and function of the patient's lower extremity. Do I worry about 1-2 degree differences in "rearfoot varus" or "forefoot to rearfoot relationship"? No. But I do take, for example, notice of gross asymmetries in calcaneal position in relaxed calcaneal stance position (RCSP) and in forefoot to rearfoot relationship since they do occur and they certainly seem to have an effect on the pathologies produced within many individuals.

Now, 30 years after I have graduated from CCPM, I don't do or pay much attention to some of the Root et al measurements that I was trained to do. In addition, I don't think that the Root et al measurements are predictive of foot kinematics or foot kinetics. However, when combining some of the Root et al measurements along with some new measurements and tests to my evaluations of patients, I do feel that I gain a better idea of the internal and external forces and moments that may be occurring in my patients' feet and lower extremities during weightbearing activities.

A few of the tests I have developed since my graduation from CCPM are as follows:

1. Determination of subtalar joint (STJ) spatial location (Kirby KA: Methods for determination of positional variations in the subtalar joint axis. JAPMA, 77: 228-234, 1987).

2. Maximum pronation test to determine how many degrees the STJ is from the maximally pronated position while the patient is in RCSP (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; Pascual Huerta J, Ropa Moreno JM, Kirby KA: Static response of maximally pronated and nonmaximally pronated feet to frontal plane wedging of foot orthoses. JAPMA, 99:13-19, 2009.)

3. Supination resistance test to determine the force required to supinate the STJ (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).

4. Functional hallux limitus test (April 2003 "Clinical Test for Functional Hallux Limitus" newsletter in: Kirby KA: Foot and Lower Extremity Biomechanics III: Precision Intricast Newsletters, 2002-2008. Precision Intricast, Inc., Payson, AZ, 2009, pp. 183-184.).

I have attached a handout from the 2011 Mancester Biomechanics Summer School that explains these and other clinical tests I have developed in more detail and gives the references for them. Hopefully, this will help explain some of the many clinical tools that I use when performing biomechanical evaluations of patients in my quest to understand the internal and external forces and moments occurring within my patients' feet and lower extremities during weightbearing activities.

 

So, everyone who has a callus sub 2nd MPJ must have a dorsiflexed first ray and everyone with a dorsiflexed first ray must have a callus sub-2nd MPJ? Subjects without a dorsiflexed first ray will never have a callus sub-2nd MPJ and if there is no callus sub 2nd MPJ there cannot be a dorsiflexed 1st ray? Sensitivity and specificity... http://en.wikipedia.org/wiki/Sensitivity_and_specificity

 

I've read it. If you read it too you'll get the answers to the questions you posed...

 

Since we're talking about assessment of 1st ray position:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1421489/

I also agree entirely with the commentary after the paper.

Here's some of the evidence, Jeff: http://fai.sagepub.com/content/27/7/539.short your hypothetical above doesn't appear to fit with it.

This cadaver based study appears to support your second hypothetical, Jeff:
http://fai.sagepub.com/content/26/9/748.abstract

So, perhaps the assessment is only useful post surgery? Or in cadavers? Nonetheless we still have the issues of specificity and sensitivity I alluded to earlier. Perhaps some of the answers lie here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3045305/ or here: http://www.jfootankleres.com/content/2/1/8

 

Simon,

So everyone who smokes develops lung cancer and those who don't smoke will never develop it? Is that what your saying? Does smoking always cause cancer? No. Smoking is known to increase the risk of cancer just as metatarsus primus elevates increases the risk of developing a sub 2nd intractable plantar keratoma. It, like cancer often has a multifactorial cause. When the podiatrist examines the patient and finds the presence of an elevated 1sy met, they have found one of the potential cause of the IPK. During their comprehensive examination, which should include a gait evaluation, they may find other contributing factors (such as equinus) or they may rule them out via a diagnosis of exclusion. This finding may be an indication for surgery in some cases, which might involved surgically plantarflexing the 1st met. The fact that you are not a surgeon may be one reasons why your form and practice of biomechanics is so much different than any of the podiatrists I deal with here in the U.S. If you were considering surgical and non-surgical intervention, I'm suspect that your approach to biomechanics would have to be different than it is and I suspect it have to depend more on structural analysis of the foot than it does now.

Jeff

 

Does it? Is that what the science tells us? If it does raise the risk, by how much?

Yep, probably something like P = G + E + (GxE)+ i

What kind of comprehensive examination should we perform, Jeff? I would say the tests should be valid, reliable, be specific, sensitive and have precise predictive value. Which of the tests that your father advocated have been shown to offer this?

What does the research (some of which I posted earlier), tell us about the relationship between the plantar callus patterns and the biomechanics of the foot?
"Although there is no previous evidence of callus being linked to range of motion in foot joints, our finding of a slightly larger range of ankle dorsiflexion in those with forefoot calluses is somewhat counter-intuitive, given that reduced ankle motion has been shown to increase fore- foot loading in people with diabetes [35]. However, ankle flexibility is positively correlated with walking speed [36], and walking speed is in turn associated with higher fore- foot pressures [37]. Therefore, it is possible that increased ankle flexibility in those with calluses is a marker of increased walking speed, which was not analysed in this study. Further research involving concurrent measure- ment of dynamic ankle motion and plantar pressures would help clarify this relationship."

Jeff, you are not even a podiatrist nor do you have any formal qualifications in biomechanics as far as I am aware, so don't start slinging stones about the way I do or do not approach biomechanics because I don't perform surgery- you are not even licensed to practise podiatry. Can you tell me and the other readers exactly how I approach biomechanics? For the record, I made a decision at the age of 21 to try to pursue a career in clinical research rather than attempt to train in surgery. Seems to have stood me in good stead.

 

Simon,

I in no way intended my comments as a criticism of you. I was just pointing out the fact that I believe that your approach would need to be different, in some way, if you were a podiatric surgeon. I feel that podiatry and podiatric education in the U.S. has turned away from biomechanics and has become too surgically oriented. And I believe that we need a system of classification like that of Dr. Root so that highly trained, clinically oriented PhD's like yourself and podiatrists of all levels of training can communicate with lowly lab technicians like myself and with their even more ignorant patients, using generally accepted terminology.

Jeff

 

Kevin, because you have done these measurements so many times, I believe you when you say that you can pick up subtle differences between feet. However, when you put your instructor hat on, can you articulate those differences to a novice? Sure there is the finding the asymptomatic tarsal coalition when you do the range of motion of the STJ. How, much of the information that you gain is of a subconscious nature, that is difficult to articulate to a novice. It reminds me of listening to Howard Dannenberg speak about observing FScan rollover processes. If you look at enough of them, while altering orthotics, there must be something that you can absorb. However, I'm not sure that he can write down a recipe of how he alters an orthotic based on the subjective observation of the rollover process. (If you don't actually compare numbers it is a subjective observation). When you measure a forefoot to rearfoot relationship do you make a mental note of how you are going to change the prescription for that patient in a similar manner to the though of adding a medial heel skive when you see a medial STJ axis?

Is there a subjective sub conscious value to performing all the measurements? Or, does it come down to when you see x you do y?

Eric

 

No offence taken.

But you don't know what my approach is, so how do you know it would need to be different if I were a surgeon? If I decided to train as a surgeon tomorrow, would I need to forget everything I've learned about biomechanics?

As an outsider who visits on occassion I'd say there are a number of reasons for this, not least a financial interest. However, Kevin touched upon it earlier- too often in the US biomechanics = foot orthoses and I have to say, foot orthoses = Root approach. Perhaps the disinterest stems from the educational set-up?

Jeff, you are not a lowly lab technician (you know that I greatly admire you and enjoy your company when we're together at meeetings) and I'm sure that I, Kevin, Eric, and all who try to employ modern biomechanics terminology in our clinics are all capable of communicating the ideas with patients, technicians and all.