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PRONATION:90% orthotics are medial skive and first ray expansion

Discussion in 'Biomechanics, Sports and Foot orthoses' started by fabio.alberzoni, Apr 17, 2015.

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  1. fabio.alberzoni

    fabio.alberzoni Active Member


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    Hi everbody!

    In these days I'm thinking about my orthotic treatments.
    I read a lot about tissue stress theory(TST) and how this is better, or at least an improvement of Root Theory.

    Well...summarily

    I think that Root did varus post on flexible supinated forefoot...that's wrong(modern biomechanics).

    I think that the main concept of the TST is the ZOOS (zone of optimal stress).very interesting but difficult to measure exactly.

    Everybody says Root is overcame...well but he propouse a protocol. does exist a new protocol?
    the casting technique is still used with some modification and we still analyse the foot with the same way...forefoot/rearfoot, tibial angle,tibial stance, rom of I MTPJ, RCSP, NCSp...

    new concepts? maximum pronation test(MPT), find STJA and supination resistence test(srt) ECT ECT..


    ORTHOTIC for pronation: 90% help I MTJ and use inverted poor and medial skive.


    In my opinion I feel confused. There's no consensus and a standard protocol.
    We talk about great theories but practically from 1992 we are doing MEDIAL SKIVE some one proposed MOSI. Inverted pooring and BIO are other extra options.

    Well..reading this 1994 article http://www.ncbi.nlm.nih.gov/pubmed/8205510 we understand that we are still doing more or less the same of Withman and Roberts using different materials.


    MY OPINION: the foot is the same since forever but the treatment...in the end is more or less the same.
    I love the effect of MEDIAL SKIVE but seems to me that we still have to improve something.
    We know that midtarsal point of view of Root is not exact but good for educational approach.

    I'd like to have a more complete protocol.I heard about cuboid mobilization in osteopathy...well...couldn't an orthotic work on this?or on other parts of midtarsal joints?
    I feel many of us have a big bug in muscolar analysis of the lower limb and that foot consist only in STJ, first ray, ankle rom and forefoot/rearfoot relationship.

    I do the same ortothic on intrarotated and extrarotated lowe limb with the same pronation...I don't like gait plate... possible?really two different limbs needs the same treatment?
    the V,IV,III,II rays? are they unpleasant?

    This wanna be a provocation to understand more. :deadhorse:

    Let me know your opinion or teach me something more.

    thank you all


    fabio
     
  2. efuller

    efuller MVP

    I do not prescribe medial heel skive anywhere near 90% of the time. One thing to add to your protocol is making the decision of whether to add a medial heel skive based on the position of the STJ axis. You have to develop a sense of who is more medially deviated and who is more laterally deviated.

    Not all pronation is caused by ground reaction force. Many people with laterally positioned STJ axes will pronate because of their peroneal muscles. These will be late stance phase pronators. These folks usually do badly with a medial heel skive device.

    To simplify the understanding of prescription writing for orthoses you could break it down to the following choices. You can a rearfoot varus or valgus post. You can add a forefoot varus or valgus post. You just need to decide if the particular pathology that you see will benefit from one or more of those choices.

    You could google the term "podiatry arena: maximum eversion height" to see the thread where the maximum eversion height test is discussed. I use this test to decide whether to add a forefoot valgus wedge effect in my device.

    There is an old test that was taught to me by John Weed. You can attempt to run your fingers under the medial and lateral forefoot of a standing patient. If you can run your fingers under the first met head of a standing patient, there is a good chance that they will be helped by a forefoot varus extension added to the orthotic. There are some exceptions, but that is the basic tissue stress approach prescription writing protocol that I use.

    Eric
     
  3. fabio.alberzoni

    fabio.alberzoni Active Member

    Thanks eric!
    I said "summarily".
    I said 90%. Well my 90% could be 18 orthotics for foot pronation por year.I suppose you do many more than me.
    In any case I never see a lateral stja foot who pronates. Probably cause I'm not good as you...
    My opinion is really weak cause of my lack of experience and I appriciate a lot that you share your important experience with me and everybody here.

    what I want to say is that looking at the orthotics I feel that miss something...I don't know what but there are a few of modification for a lot of patologies. And a medialized STJA before which cause a pronation and a fascitis before of TST was treated with anti-pronation modification and still now is what we do.


    ABOUT WHAT YOU SAID:
    1. pronation caused by peroneal muscles. how can you understand if a late stance pronation is caused by peroneals? many time I saw this in equinum.
    If late pronation is caused by peroneals which modification in orthotic you use?

    2.test of wood: I saw this in Spain many times. do you use this to understand if is rigid varus/valgus forefoot?

    thanks!
     
  4. efuller

    efuller MVP

    When the foot is on top of the orthotic, the orthotic will push upward on the foot in slightly different amounts and in different areas that when the foot is standing on a flat surface. Your prescription changes the shape or the orthotic to push on the foot more or less, in various locations. One way to simplify how you look at the orthotic is that there are pronation related problems and supination related problems. The Pronation related problems you treat by increasing supination moment by shifting the center of pressure more mediallly to decrease the pronation moment from the ground. Use the opposite for supination related problems.




    With late stance phase pronation, in gait you will see pronation begin at contact and when the medial forefoot contacts, the pronation slows or completely stops. Then a little bit later, there is additional pronation of the STJ. So, after the first stopping of STJ pronation, there is additional range of motion available. So we know that the medial forefoot can create a supination moment to stop the STJ pronation. Then as tension in the Achilles tendon tension increases, the Achilles tendon will create some supination moment. If the peroneal muscles don't add a pronation moment, the foot would just continue to supinate toward the supination end of range of motion (sprained ankle).

    In the medially deviated STJ axis foot, the medial forefoot does not provide a large enough supination moment to stop the motion before it reaches the anatomical end of range of motion. So, there cannot be late stance phase pronation, because there is no more range of motion available. Also, the forces on the forefoot will continue to cause a pronation moment that will most of the time be higher than the supination moment from the Achilles tendon.

    So, to treat pronation caused by the peroneal muscles, your orthotic should attempt to pronate the STJ to its anatomical end of range of motion. Here on the arena I've discussed a test I've called the maximum eversion height test. Are you familiar with that thread? Any way an intrinsic forefoot valgus post will tend to move the STJ closer to its maximally pronated position. When the STJ is more pronated, the STJ aixs will move more medial.


    By test of wood do you mean the Coleman block test where a piece of wood is placed under the lateral forefoot and motion, or lack of motion is observed in the STJ. In the laterally deviated STJ axis foot, the STJ will sit in a position where there is additional range of motion available. When the block is placed under the lateral forefoot the STJ will evert. In the medially deviated STJ axis foot the STJ will tend to be at its end of range of motion and the block under the foot won't cause any further eversion motion, because none is available. The maximum eversion height test is essentially the same thing as the Coleman block test.

    Eric
     
  5. Ian Linane

    Ian Linane Well-Known Member

    Hi Fabio



    Regards your question: "I heard about cuboid mobilization in osteopathy...well...couldn't an orthotic work on this?or on other parts of midtarsal joints?"

    I guess mobilisation is more my area of interest. There is the approach where a supportive element (cuboid pad) is built into a shoe inlay or upon an orthotic to support a cuboid if it has already been mobilised. Some have found this useful (though it is not something I do myself) and that seems to be about it in terms of some orthotic support. It would be difficult to contrive a device to mobilise a cuboid on a weight bearing foot as the joint would likely be more congruent and tissues around it likely under tension. An exception to this is mulligan mobilisation with movement (MWM) approaches when you can mobilise the cuboid in a semi-weigh bearing position. This would be done from a dorsal angle though.

    I suspect similar limitations occur if you are thinking MTJ or bones of the tarsus.
     
  6. Petcu Daniel

    Petcu Daniel Active Member

    Why somebody will prescribe a medial heel skive to a laterally positioned STJ axes ?

    How do you "see" this, especially in 2 situations:
    1.- when there is available the Cop trajectory,
    2.- when you have to rely only on your eyes ?

    Thanks,
    Daniel
     
  7. efuller

    efuller MVP

    I see this when patients come to my office with an orthotic made by someone else. What I believe happened is that the person who prescribed the orthotic added a medial heel skive because they saw a pronation related problem and they did not check the STJ axis location. There is an orthohtic lab here in the U.S. that makes pathology specific orthoses that have a medial heel skive for bunions. Some people with bunions have laterally positioned STJ axes. So, the person writing the prescription could have ordered a medial heel skive unknowingly, if they did not read the fine print of what comes with the orthotic for a bunion.

    If you have a CoP trajectory you will see a medial shift in the trajectory in the forefoot. I have a picture, but it won't upload because it isn't the right format.

    With your eyes you will see internal leg rotation just before heel lift. When standing, if you ask a patient to evert, and they have range of motion, you will see the same motions that you see in gait. When they are standing, you can actually see the calcaneal eversion. It's too far away to see that in gait with the naked eye. However, the other motions that go along with calcaneal eversion can be seen. For example, internal leg rotation, increased medial prominence of the talar head. In a lean patient, you will see the peroneal tendons. I haven't been able to do a comparison to see late stance pronators have dramatically more prominent tendons than those who do not show late stance phase pronation. (That would be a good EMG study). Of course if you have access to slow motion video it is much easier to see these things.

    Eric
     
  8. Petcu Daniel

    Petcu Daniel Active Member

    Dr. Fuller,
    How important it is the position of the proximal border of the intrinsic valgus post ? Should this intrinsic forefoot valgus post start from the cuboid area ? I'm thinking that peroneals will better benefit from an intrinsic forefoot valgus wedge extended proximally till the cuboid area. Am I right ?
    Thanks,
    Daniel
     
  9. efuller

    efuller MVP

    Daniel, I'm not quite sure what you mean by the proximal border of the intrinsic post. I'm talking about the cast modification described by Root. (I beleive it was 1994 in clinics in podiatry). A nail is placed in the fifth met head of the positive cast and this everts the heel and raises the lateral plantar foot higher off of the ground. A platform is added to the positive cast. The blend from the original foot (cast) to the platform is very short < 1 cm. The orthosis, when finished must end on the platform. So, when you compare an orthotic that was made with an intrinsic post, to an orthotic without an intrinsic post, the shapes will be the same except that the one with the intrinsic post will have a downward curvature in the last centimeter. This downward curvature lifts the lateral side of the orthotic higher off of the ground just as a valgus wedge would. The same as a valgus wedge placed between the calcaneus and a centimeter proximal to the fifth met head. So, an intrinsic forefoot valgus post should support the cuboid.

    Eric
     
  10. Petcu Daniel

    Petcu Daniel Active Member

    I'm thinking at the situation when we are using a prefab and we have to add a prefab forefoot valgus wedge which length doesn't cover the distance between cuboid and 5th metatarsal head. But you give me the answer, at the end of your post!

    Thanks,
    Daniel
     
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