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Our fascination with plantar-flexing the 1st ray - orthotic implications

Discussion in 'Biomechanics, Sports and Foot orthoses' started by Atlas, Feb 14, 2007.

  1. Javier:

    Do you have a better method by which to alter the ground reaction forces on the plantar foot of a patient in a fashion that is tolerable to the patient, reduces or eliminates their symptoms and allows the patient to have this same therapeutic alteration in ground reaction force step after step, day after day, year after year, with a minimum of servicing from the podiatrist??

    By the way, Javier, a Yugo achieves similar results to a Porsche, if all you are looking at is going from point A to point B. :cool:
     
  2. Cheers for that. Next weeks worth of insomnia sorted! :mad: A frightening relevant and thought provoking point.

    I would point out that the cast is only the start point of what eventually gets turned into an insole. Modifications and postings (hopefully) move the cast away from it's pathological origins. However the point is a good one worthy of considered thought.

    Thanks for the headache. :(

    And don't worry Javier. I'm told the sharks only bite snakes ;) .

    Regards

    Robert
     
  3. javier

    javier Senior Member

    If your only purpose is to alter GRF on the plantar foot, there are many ways for doing so from shoes to orthoses. But, as you pointed out is some previous post, evaluating GRF in isolation can lead to error.


    I am not questioning the useful from foot orthoses, just pointing out some flaws: "Paradigms call for critical engagement, not dogmatic adherence" CRAIG B. PAYNE,The Past, Present, and Future of Podiatric Biomechanics J Am Podiatr Med Assoc 88(2): 53-63, 1998), this sentence can be used also for processes.

    Regards,
     
  4. CraigT

    CraigT Well-Known Member

    Why would we cast a non-pathological foot??? :p
    We cast for specificity. Surely a foot only becomes pathological once there is an interection with GRF's- how the GRF's act on the foot has much to do with the shape of the foot... as well as alignment, axial position, ROM... so on and so on...
    The cast is taken so that you have a starting point to change the GRF's- it will be more specific than any prefabricated device, although, granted, in some cases this difference may be minor.
    The use of prefab orthoses will often improve symptoms, but is symptomatic relief the only thing we are aiming for? We are the foremost experts is assessment and treatment of the foot and lower limb- I think we should be aiming a lot higher than relief of a presenting symptom. I do not see many patients where I look at a prefab device under their foot and think 'you can't do any better than that'. Would you ask a surgeon not to do their best work??
    By the way Kevin- I like the Yugo- Porsche analogy- might use that one. :)
     
  5. javier

    javier Senior Member

    It would improve chances for success, would not it? ;) :)

    I prefer to say that symptoms arise when our body have to deal with gravity.

    Nice weekend!
     
  6. CraigT

    CraigT Well-Known Member

    indeed! :D

    You have a good weekend too!
     
  7. Javier:

    There are a few ways in which I can try to point out the answers for the question you posed:
    One of the ways would be to ask you to go step by step in describing how you think foot orthoses should best be done and why it should be done that way. Then, along the way of you trying to describe the best way to perform this ideal mechanical therapy, I would point out to you why the solution you had picked is likely to be mechanically inferior to the way that podiatrists have been making custom foot orthoses for over half a century, that is by making an three-dimensional impression of their characteristic plantar foot morphology.

    However, Javier, since you don't seem to want to answer my first question:
    then I will give you an analogy.

    If you were to bring your young teenage daughter to an orthotist for fabrication of a custom back brace due to her moderately severe scoliosis, and the orthotist told you that your daughter didn't need a custom back brace, made from a three-dimensional mold of her upper torso, but that she needed a generic back brace, made to fit the average shape of a young teenage female's torso, what would you think of that orthotist?? Would you agree with his methods with your knowledge regarding the response of soft tissues to areas of chonic high compression pressures? What would you imagine may be the potential discomfort that your daughter would be subjected due to these chronic high soft tissue compression pressures as a result of trying to wear this "normal shaped brace" for her "pathologically shaped torso".

    If you make the attempt to answer a one or more of my questions to you, Javier, then I will proceed further with my mechanical explanation of why custom molded foot orthoses made around the shape of the patient's "pathological foot" would have a much better chance for success than a non-custom molded, non-modified over-the-counter foot orthosis made around a "normal foot".
     
  8. javier

    javier Senior Member

    Hello Kevin,

    I suppose you understand how difficult is to write using a language that is not your own. I will expend some of my weekend time trying to give you a more lengthy answer. I will do the best I can. Let's go!

    It happens that I am also orthotic technician, thus I have some experience about back braces. It is not a good analogy, although I understand your reasoning: a custom made device is better than a prefabricated one. It is not entirely true. There many types of scoliosis and its treatment goes from a prefabricated devices such a Boston brace or a Milwaukee brace (although Milwaukee can be partly custom-made) to provisional devices made of low temperature thermoplastics that you can adapt directly to the patient or full custom made braces. Also, you can take a mold from the torso using plaster of Paris or using modern techniques based on laser scanning and CAD-CAM manufacturing. Also, there are important difference about how a brace performs comparing to a foot orthotic. As a rule, a brace for scoliosis works on the frontal plane "pushing" apical vertebras to correct convexity, they can work also on the sagital plane keeping a straight posture and on the transverse plane for vertebra rotation correction. But, as you know spinal biomechanics differs from foot biomechanics.

    Before asking your question, I would like to point out some facts:

    - There are many paradigms that explain foot function, foot pathology and foot conditions treatment. Most of them have shown a similar rate of success or failure. We could conclude that outcome differences are more related to clinician experience than to paradigm accuracy.

    - Millions of orthotics are made worldwide. For instance a German Fuß-Orthopädie Technik, who has never read your papers, can avaluate and manufacture a foot orthotic that it will solve the symptoms from any patient.

    - If we except some "exotic" orthotics (f.e rothbart insoles), all orthotics made worldwide share a similar shape supporting medial longitudinal arch.

    - Foot arches are the one of the most evident human anatomical characteristic.

    Here it goes my reasoning:

    Most of the cases, when you perform a patient evaluation you detect asymmetries between right and left extremities. Moreover, feet loading is not symmetric. There are differences between feet to loading response, thus when we have to deal with gravity these asymmetries can lead to pathology. Of course, it is far from an original reasoning because it has been partly stated by other authors such as Howard Dananberg. There are some interesting lectures about the subject on http://www.kalindra.com/montreal2001.htm

    Thus, casting a pathological foot is not the best way for compensating these asymmetries. How it can be done? You can take foot measurements for grinding a orthotic by hand or using CAD-CAM technology. At the end, you will have a 3-D device that will interact with the 3-D shape of the foot.

    But, if you (I am not referring to you particularly) think that it is nonsense and you follow STJ neutral theory, then you will need a cast posted and balanced for keeping the rearfoot vertical. All paradigms have their theory and processes. From my point of view, you will support the midfoot by one way or another.


    Perhaps, I was misunderstood in my previous post. I was not saying that a OTC orthose was better than a custom molded foot orthose. Just, it was not surprising that OTC orthoses achieve similar results to custom molded foot orthose in some papers considering the modifications that are done to the casts.

    Finally, I want to say that I cast the foot for accommodative devices in diabetics or rheumatic patients for obvious reasons.

    Regards,
     
  9. You do much better than I ever could in Espanol. So I will expend some of my valuable weeked time trying to give you responses to your statements.

    My point in using the analogy of the teenage girl getting a back brace is that just like using a non-custom back brace, non-custom molded foot orthoses will be more likely to give irritation to the plantar foot structures than custom molded devices due to the higher contact pressures involved from having a non-custom fit shape. This does not mean that custom-molded devices are always better than over-the-counter (OTC) orthoses, but in general, patients are much more comfortable, and for a much longer time frame in custom-molded foot orthoses than OTC orthoses.

    I have had the benefit of being referred, over the past 22 years, a wider range of foot pathology than most podiatrists will ever see in their practice careers. This has allowed me to see and treat the wide range of pathologic foot structures that are present in the human population. If my goal is to modify the plantar reaction forces (PRF) on the foot so that I can accomplish the task of:

    1)relieving the patient's symptoms caused by pathological internal or external forces,
    2) optimize their gait pattern, and
    3) not cause other pathology to occur,

    then in my experience, I must do one of the following two things:

    A) I could use an OTC device and then spend considerable time modifying it to fit the specific plantar contours ,see the patient back every month or two to keep adding corrections to make up for the deformation and compression in the orthosis materials that would likely occur over time.

    B) I could take a three-dimensional image of the patient's plantar foot and then use that to have a more deformation-resistant material made that would allow me to accomplish the same goals but have it last years without me needing to see it again, and without the patient needing to bother to see me again.

    Which of these two methods is better for the patient, Javier?

    One does not to read any of my books, book chapters, published papers or postings to Podiatry Arena to make good foot orthoses. However, I do believe that one needs to try to duplicate the plantar contours of the individual's foot with a foot orthosis in order to optimize the therapeutic function of the foot orthosis.

    However, Javier, by grinding a orthotic by hand or using CAD-Cam technology, you are still making the orthosis to "the pathological shape" of the patient's foot. You stated:
    If it is a flaw to manufacture orthoses about a cast, then why is it not also a flaw to grind an orthosis by hand or use CAD-CAM technology to produce a 3D device that matches the shape of the "pathological" 3D shape of the foot? :confused: :eek:

    No matter what theory you adhere to, podiatrists who are experts at foot orthosis therapy around the world use a three-dimensional modelling method (casting, foam box, optical scanners, contact digitizers) to ensure proper orthosis contact with the foot. And supporting the midfoot is just one of many important functions of a custom foot orthosis.

    When you make a statement such as: "One of the many flaws about orthotics manufacturing is about the cast. Why do we cast a pathological foot? We will get a pathological cast! Afterwards, it will be modified and posted according to certain protocols and at the end you get....what? It is not surprising that "custom"-made orthotics achieve similar results to prefabricated devices.", then what is to misunderstand?? You asked why we cast a pathological foot to get a pathological cast, and I replied.

    You must be careful, Javier, when you say "prefabricated devices" that you say whether those prefabricated devices have been modified by the clinician or not. Like other researchers recently that claimed they were using prefabricated devices in their orthosis study, but were instead custom-modified prefabricated devices, these are two very different animals. The prefabricated device is made to a normal foot. The custom-modified prefabricated device is made to the pathological foot. They are not the same, even though they started out being the same when they were taken off the shelf.

    Hope you are able to enjoy the rest of your weekend.
     
  10. javier

    javier Senior Member

    I think that almost every practitioner have experienced some irritation complaints involving custom and non-costum devices. Of course, I can not offer data about in which percentage occurs. Perhaps there is an study out there.

    I agree.

    As you have stated above, treatment selection will depend on every case. But, I think that we talk about different devices due to OTC vs prefabricated. In Spain, there are not OTC devices in your fashion available for the public with the exception of "shock absorbing" insoles. Prefabricated devices or as you said custom-modified prefabricated devices are widely used in orthotic manufacturing. Anyway, it was not what I had in mind when I post my opinion.

    My question was: What do you get when cast modification is finished? Which is the result? Did it is what you wanted or something completely different?

    Yes, but as it has been discussed and published there are more accurate systems than others.

    As I said above, it was my mistake not using the proper definition. For clarification: an OTC orthose is a device that for definition it can not be modified and a prefabricated orthose is a device that can be modified by an expert for achieving a goal or goals for a certain patient. Is it correct? Then, I was talking about OTC. But, although they are different animals their results bring some inconvenient questions.

    Regards,
     
  11. Javier:

    Orthosis irritation does not just occur with premade orthoses. I get plenty of orthosis irritation with the custom molded orthoses I make for patients. That is the "price one must pay" when using less forgiving materials such as polypropylene in order to give the patient's orthoses much more durability. However, most of these cases of orthosis irritation I can solve with various types of adjustments.

    Glad to see you don't really have a problem with making 3D images of "pathological foot shapes" when you make custom foot orthoses.
     
  12. Jeff Root

    Jeff Root Well-Known Member

    Kevin,

    I happened to be skimming the topics on the Podiatry Arena newsletter and I noticed two subjects that caught my interest (What holds the arch up and Our fascination with plantar flexing the 1st). Unfortunately I don’t have time these days for involvement on these forums but I do miss and appreciate the value of them!

    Kevin, you wrote: “First ray cutouts are not something I have used or have felt the need to use in my patient's orthoses. Mert Root's orthoses were made to the first metatarsal bisection which is more wide than a true first ray cutout.”

    Actually, your statement is incorrect. Root Laboratory, since 1974 and to this very day makes the standard width of their orthoses to a point which is halfway between the 1st interspace and the bisection of the 1st metatarsal head. Mert wrote: “On the distal, medial side of the orthosis, the standard functional orthosis should be ground so the orthosis lies on the lateral edge of the medial balance platform. It is desirable to use as narrow an orthosis as possible anteriorly so the orthosis does not restrict normal plantarflexion of the 1st ray as propulsion occurs.
    Practitioners who prefer wider orthoses may request that the distal aspect of the orthosis be ground so that the medial side terminates at either the center or the most medial side of the balance platform”.
    ref. "Development of the Functional Orthosis" Merton L. Root
    Clinics in Podiatric Medicine and Surgery Vol. II-#2-April 1994

    The center of the medial balance platform corresponds with the longitudinal bisection of the 1st met head. Root’s devices were definitely on the narrow side because he was keen on 1st ray plantarflexion (windlass, etc.). Since you can easily narrow an orthosis, you can always make it wider if desired, provided you monitor function and then narrow it, when necessary. A wider orthosis will not necessarily create FHL, but it has the potential to.

    In some percentage of cases, an orthosis will adduct in the shoe. In such cases, we at Root Lab have periodically applied or have advised practitioners to apply a Korex buttress to the anterior, medial aspect of the orthosis to resist medial migration of the orthosis since the 1970’s. In my opinion, adduction of the orthosis occurs when the orthosis attempts to resist the transverse plane component of STJ pronation, but slides medially due to insufficient friction on the plantar, distal edge or because there is an increased ratio of transverse plane motion at the STJ (high STJ axis). It also occurs when there is an excessive range of transverse plane motion at the MTJ, which allows the forefoot to abduct off the device, thereby driving the orthosis medially (think of the adult acquired flatfoot as an extreme example). This action can typically be prevented by with the addition of a medial Korex buttress but in some cases, necessitates making a more controlling orthosis to prevent this hyperpronation at the MTJ.

    The subject of plantarflexing the 1st ray during casting seems to be a hot topic these days. In my opinion, it seems ridiculous since virtually every commercial lab puts too much filler in the forefoot and their orthoses don’t begin to reflect enough valgus forefoot support in the first place. What’s the point of increasing the valgus attitude of the forefoot if the lab is just going to wipe it out with their “cast corrections”? If you want to control the MTJ with a potential retrograde influence on the STJ, then ask your lab to leave the valgus correction in the forefoot. Most the “custom” orthoses I see these days are so generic looking, it’s no wonder orthoses are rapidly becoming a retail commodity. The days of the medical grade orthosis will be gone if the “professionals” keep demanding mediocrity from the labs.

    Respectfully,
    Jeff Root
    www.root-lab.com
     
  13. Jeff:

    Thanks for that clarification. I have been missing your input on this forum.

    Myself and many others have made their orthoses wider than what your father originally described and what your lab standardly does for many years now, without any clinically observable deletorious effects. It makes more sense to me to fabricate the orthosis in the first place so that you won't need to glue a piece of korex to it to make it fit under the foot correctly inside the shoe. I haven't seen any "restriction of first ray plantarflexion" with my wider foot orthoses.

    Anyway, the first ray doesn't plantarflex until the heel is lifting and this is probably why there hasn't been problems noticed with the wider orthoses that myself, Rich Blake, Jane Denton, Larry Huppin, Eric Fuller and many other podiatrists have been using for over the past few decades.
     
  14. Jeff Root

    Jeff Root Well-Known Member

    Kevin,

    I don't see any problem with making orthoses a little wider as long as one evaluates the patient and adjusts the orthoses when necessary. It is much more common to have to narrow an orthosis than it is to buttress it. Both are easy adjustments.

    Even if we make the forefoot width narrower as I described, it can sometimes be nearly as wide as the shoe. The shoe tends to compress the metatarsals, so even though we use a non-weightbearing cast, the weightbearing splay may be mitigated by compression from the shoe. There is a lot of vairation between shoes. In any case, we have six options for forefoot width on our Rx so the practitioner can select the width that they want.

    Another important variable is the actual width of the individual's forefoot. There can be significant variation in the anatomical width of the forefoot with individuals wearing the exact same brand and size of shoe. If the patient has a narrow forefoot, then there may be more room for the device to migrate medially. Conversely, if they have a wide forefoot then a standard width device may be too wide for the shoe. That's why prescriptions should be made according to needs of the individual patient and that's why it is sometime necessary to modify or adjust an orthosis.

    When I make a narrow forefoot, I often like to use a wider medial arch profile to offset the loss of surface area. You can also add a non-corrective forefoot post to increase the plantar surface area and stabilize the distal edge of the device. I have found that a narrower orthosis can help in some cases of hallux limitus.

    Regards,
    Jeff Root
    www.root-lab.com
     
  15. Atlas

    Atlas Well-Known Member

    I like the look of the Richie Brace (for talo-crural and STJ pathology) on your site. What is the process of ordering internationally? Do you have labs in other countries that can do it? Do you get computer scanning data sent?

    Ron
    (Melbourne Australia)
     
  16. Jeff Root

    Jeff Root Well-Known Member

    Ron,

    Thanks for your inquiry about the Richie Brace®. I am very careful not to participate on these forums for commercial purposes. I try to avoid those topics where I have a direct commercial interest in order to protect my credibility and personal reputation. Like many others, I personally don’t care for the infomercial type of contributions on these forums, especially when the contributor doesn’t have the courtesy to defend their claims when challenged! My participation is intended for educational purposes. I find I learn a great deal from others (Kevin, Bruce, Simon, Howard, et al) and I enjoy the occasional opportunity to help educate others with my own contribution. Since I will refer you to a Richie Brace® distributor in the UK, I will be happy to expand on your inquiry publicly.

    While I could provide you with the Richie Brace®, there are a couple of established distributors in the UK that can probably provide you the brace more cost effectively. I think Firefly and Allied OSI are two of them (see http://www.richiebrace.com/lab-partners.htm for a list pf distributors). The Richie Brace® is an excellent treatment modality for PT dysfunction, adult acquired flatfoot, and lateral ankle instability. The dynamic assit has dorsiflexion assistance for mild dropfoot. You need to use a Plaster-of-Paris or STS resin casting sock that encompasses the distal aspect of the medial and lateral malleoli. I don’t believe you can use CAD/CAM or digital scans at this point in time. You should take a non-weightbearing cast since the foot plate is intrinsically corrected and it is recommended that you cast out any forefoot supinatus. For the California AFO you need the cast to be at least nine inches above the supporting surface. Here is a link for the recommended casting techniques (http://www.richiebrace.com/orthotic-afo-casting.htm).

    If you haven't tried a Richie Brace, I would encourage you to do so. I hope I have answered your questions to your satisfaction.

    Respectfully,
    Jeff Root
    www.root-lab.com
     
  17. Jeff:

    I have been teaching residents and podiatrists to make orthoses to the width of the shoe for the past two decades. This involves making the orthosis wider than the first met bisection for narrow feet and lateral to the first met bisection for very wide feet which is consistent with your remarks above. However, I draw a line in the negative cast of the foot to indicate to the orthosis lab how wide to make the orthosis.
     
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