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Help with orthotics

Discussion in 'Biomechanics, Sports and Foot orthoses' started by suzilobo29, Jul 27, 2008.

  1. suzilobo29

    suzilobo29 Welcome New Poster


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    I've got a pt with a partially compensated rearfoot varus. He presented due to his wife claiming he 'walked funny' and has mild bilateral knee pain which he attributes to damaged cartilage. He is a heavy fellow. In gait he pretty much stays supinated throughout the cycle with heaavy heel strike. I have got him into a pair of formthotics with the goal of reinforcing these with poron when I establish his wear pattern. I was thinking of building up the medial side of the foot but this may cause lateral ankle instability which he has previously not complained about. Any suggestions? :dizzy:
     
  2. David Wedemeyer

    David Wedemeyer Well-Known Member

    What other information can you share with us suzilobo?

    Is the rearfoot flexible or rigid? I would assume this gentleman has a cavus foot type? Is there significant tibial varum? How about forefoot valgus?

    The cavus foot tends to be a supinator and are the most challenging patients I have encountered. I believe from what I have learned in practice (and especially in reading Dr. Kevin Kirby's papers it is a concept reinforced here frequently) is that the STJ axis in these patients tends to be deviated laterally.

    This would make the standard approaches less effective, ie; merely building up the medial arch and rearfoot extrinsic posting.

    One of the most important paper that I have ever read and one that addresses this issue specifically, is Dr. Kirby's "Rotational Equilibrium Across the Subtalar Joint Axis". If you search around the board there are numerous discussions of these issues.

    Good luck
     
  3. suzilobo29

    suzilobo29 Welcome New Poster

    Hi David,
    Thanks for the reply. This patient does indeed have a cavus foot type and tibial varum. He has a forefoot valgus also. The foot is pretty stiff all round. My intentions were to simply accomodate his foot type and not try to reposition it due to his limited rom. I actually have the rotational equillibrium paper to hand, and on reflection, yes I see what you mean: I may be increasing the supination moment in a foot type like this by medially posting. I would be glad of any further suggestions you may have. :dizzy:
     
  4. Where is the knee pain?
     
  5. David Wedemeyer

    David Wedemeyer Well-Known Member

    suzilobo,

    I have had good results with Northwest Podiatric Labs composites (2-D flex) and flexible copoly's even with a rigid cavus foot. I know that I may be bucking convention here and am opening myself to being beat about the torso by some for not using strictly accommodative materials on the pes cavus foot :hammer:.

    I am confused though because you describe a partially compensated rearfoot varus and yet you state that his "foot is pretty stiff all around" Have you performed a Coleman Block Test on this patient?

    After reading the paper on Rotational Equilibrium and as I began to grasp the concept of deviated STJ axes, I shifted my focus to the patient's symptoms and not merely on what I can see and feel on exam. I have had many patients similar to the one that you describe; pes cavus, varus rearfoot, forefoot valgus, medial (I am guessing with your patient) knee pain.

    They often have cuboid, sinus tarsi and 5th met isssues in some combination. If the rearfoot is partially compensated and the Coleman Block Test is positive, then I would tend to believe that this patient has enough range of motion and flexibility in the STJ to allow you to use a lateral heel skive to resist excessive supination moments and the devices will be comfortable for the patient.

    Certainly you could cause iatrogenic lateral column symptoms if you merely "build up the medial arch" and ignore the supination moments in this foot type. I also have found that many of these patients have a platarflexed first ray and often lack dorsiflexion stiffness at the first ray. Functional hallux limitus and apropulsive gait with a supinatory rock at push-off are common findings. Once you shift the STJ axis more medially there are these issues at the 1st met joint to assess and consider when prescribing.

    I would consider based on what you have told us here using tight arch fill, a deep heel cup, lateral heel skive, forefoot valgus posting (based on the Lateral Forefoot Elevation Test), possibly a 2-5 bar, valgus wedge extension, Poron atop the devices for cushioning.

    Any cuboid or 5th met symptoms can be addressed with the appropriate cutouts and cookies.

    I often use a 2-5 bar in these patients because they offload the forefoot during propulsion. NW Podiatry does an excellent job of extending the valgus post in the forefoot of the device and patients report the post and extension are comfortable.

    I hope that helps
     
  6. David Smith

    David Smith Well-Known Member

    David

    Coleman Block Test - What's that?

    Dave S
     
  7. Great, and the presenting problem is....
     
  8. David Smith

    David Smith Well-Known Member

    Suzi

    I'm a bit confused - ie you have a partially compensated rearfoot varus but the foot in gait remains supinated. Your thinking of medial posting but the fore foot is valgus. Read this thread.http://www.podiatry-arena.com/podiatry-forum/showthread.php?t=3896

    Just so we are both reading from the same page- this is a compensated rearfoot varus.

    [​IMG]


    http://www.footmaxx.com/uploaded/product_category_pdf/file_22.pdf

    Bearing in mind I'm not sure what the problem is you are trying to address, eg is it knee pain, funny walking, poor shock attenuation, wife's peace of mind??

    First (as Simon and David have implied) decide on what it is you are trying to achieve. Then if its stabilising the foot and increasing shock attenuation then, mobilise the ankle RoM. add some heel lifts, post the forefoot valgus, drop 1st ray and add 1st MPJ c/o and lower the medial arch. Do not post the rearfoot.
    Then again if he has lateral knee pain this strategy may make it worse. You should look more proximally to see what the hip and femur are like relative to the lower limb segment. If he has restricted or no internal hip rotation available then this may be winding up the knee and causing supination at the foot during swing thru. In which case you do not want to be valgus posting the foot. If the knee is hyperextending in compensation for the equinus then heel lifts and mobs may be benificial. If the knee stays flexed thru the gait then heel lifts may make this worse. If the knee pain is medial read this - (Use of Laterally Wedged Custom Foot Orthoses to Reduce Pain Associated with Medial Knee Osteoarthritis A Preliminary Investigation Russel Rubin, BSc(Hons), NHDPod(SA) * and Hylton B. Menz, PhD, BPod(Hons) Journal of the American Podiatric Medical Association
    Volume 95 Number 4 347-352 2005) or it could be medial pain below the medial tubercle of the tibia(can't recall the name of that syndrome right now but some one will remind me) in which case lateral posting will make it worse. And so on and so forth, as you can see it is vital to be clear what it is you are treating before going ahead with an intervention. Just restoring the gait to some arbitrary perception of normal is worse than pointless. Having said that, do just that and it often works but its just this side of luck really.

    All the best Dave
     
    Last edited: Jul 27, 2008
  9. David Wedemeyer

    David Wedemeyer Well-Known Member

    Simon

    I realize that you are somewhat frustrated over the lack of fine detail in Suzi's post regarding this patient. I certainly didn't mean to add to that. I agree that it is not enough information to post a succinct response. I was merely trying to open a dialogue as to how given what she has described might in fact be a whole different scenario than her initial examination and some things to consider for this patient.

    David

    As usual your post is highly detailed and well thought out. I was also confused by the presentation so I took the liberty of 'theorizing' what Suzi might be describing and some possible ideas to address them. There are often issues more proximal to address as you have pointed out. I intended to go there if and when Suzi gave a more detailed description.

    I am not afraid to either make mistakes here nor be corrected. I much prefer to make a mistake or present an idea that is corrected here than to encounter a glaring failure in practice and I do appreciate all of your input and ideas. It helps me to learn and advance my practice.

    Sadly often when one of you veterans responds I realize just how much more there is to learn and apply, which is quite humbling. I am willing to put my head on the chopping block and post because it is your responses that have helped me to gain so much in terms of my understanding of very complex subjects. I hope I didn't frustrate either of you when I responded to Suzi.
     
  10. David, not frustrated, nor trying to chop off your head. The successful application of the tissue stress model requires accurate identification of the tissue under stress. You referred to Kevin's rotational equilibrium paper; this forms part of the tissue stress approach. So I was guessing that you also probably agree with this approach.

    Now, from the original post we have:

    "He presented due to his wife claiming he 'walked funny' and has mild bilateral knee pain which he attributes to damaged cartilage. He is a heavy fellow."

    So does the patient have cartilage damage or not? Is it medial or lateral. The knee is a complex joint with many potential pathologies, without proper examination and diagnosis how can we possibly design a successful orthoses? We need to know which tissue is damaged and what its function is in order to "off-load" stress within that tissue.

    Lets say we "know" that the patient has cartilage damage. The orthoses prescription would be different depending on whether that damage was in the medial or lateral compartments- right? We can perhaps postulate given the scant details provided as to which compartment will be problematic using the tissue stress model- but experience dictates that there are tons of patients that don't "fit" the "theory".

    So my posts here were designed to get Suzilobo to make a diagnosis before selling her orthoses. In my experience this will make for more successful orthoses design and a happier patient base.
     
  11. Simons point is well made. As has been previously discussed if there is medial knee OA it might be that a lateral heel wedge is the path to joy.

    This, for me, is the problem with the "Rootian" model in its pure form. We are examining the foot in context of the "criteria for normalcy" with rearfoot alignment as one of them. However it may be that accomodating compensations is not the most appropriate treatment!

    Personally i would prefer to know the diagnosis first (what is causing the pain) THEN know the biometric peculiarities of the foot in order to know A: the potential cause of the pain (if it is an ongoing functional trauma) and B: the best way to reduce tissue stress in the affected tissues.

    Regards
    Robert
     
  12. Simon makes an excellent point here in regards to the case report inquiry posed by Suzi. There is no way I could help a fellow podiatrist with a patient if the only thing they could tell me about their knee is that their patient has "knee pain". This is like saying, the patient has "foot pain".......pretty nonspecific....wouldn't you say?

    One cannot also assume that just because a patient has medial knee pain, that the patient necessarily also has medial knee osteoarthritis (OA). Off the top of my head, medial knee pain can be caused by medial collateral ligament strain, a medial meniscal tear, pes anserinus bursitis, to name a few. Lateral knee pain can be caused by lateral collateral ligament strain, iliotibial band syndrome, popliteus tendinitis, lateral knee OA, lateral meniscal damage or biceps femoris insertional tendinitis, to name a few. Anterior knee pain can be caused by prepatellar bursitis, patellofemoral syndrome, patellar tendintis, quadriceps retinacular strain, patellar fat pad syndrome, to name a few. Posterior knee pain can be gastrocnemius muscle strain, hamstring insertional tendinitis, Baker's cyst, or a posterior capsular strain caused by hyperextension of the knee, to name a few. Internal knee derangements (i.e. anterior or posterior cruciate, medial or lateral meniscal or osteochondral injuries) can also cause knee pain, but may be poorly localized with pain on extension, knee effusion, locking of the knee and difficulty walking being evident also.

    As far as medial joint line pain in the knee, this can be caused by excessive STJ pronation moments which will cause excessive tensile stresses in the medial collateral ligament and a medial collateral ligament strain. This type of pain is nicely treated with a foot orthosis that increases the external STJ supination moments (i.e. varus wedged orthosis). However, medial joint line pain may also be caused by medial knee OA due to increased interosseous compression pressures within the medial compartment of the knee. Medial knee OA may be made worse by a varus wedged foot orthosis and, in fact, is best treated with a valgus wedged foot orthosis that increases the external STJ pronation moments.

    Therefore, to say "knee pain" doesn't help anyone with a diagnosis. Please be more specific with the anatomy. If you don't know the anatomy, then there are many excellent anatomy textbooks and knee examination textbooks that will help the podiatrist becoming more adept at performing a thorough and accurate knee examination.
     
  13. David Smith

    David Smith Well-Known Member

    pes anserinus bursitis That was the one I was thinking of

    Thanks Kevin

    Dave S
     
  14. David Smith

    David Smith Well-Known Member

    Suzi

    Thought this might help.

    [​IMG]

    If you have a foot with a valgus fore foot you could post like the top two diagrams, Depending on how you want to change the moments about a certain point eg the sub talar joint (or, theoretically, (careful here) what position you would like the calcaneous to tend towards)

    The bottom two diagrams show how posting can result in reduced tension in a tissue e.g. a tendon, but no change in the position of the joint. This would be useful if the tendon was over stressed and painful. Oh! d = lever arm length.

    Hope this helps

    Dave Smith
     
  15. efuller

    efuller MVP

    Expanding a little on the coleman block test question:

    Differentiating between rearfoot varus and rigid forefoot valgus is something discussed within the Root paradigm. Often not directly, but it was discussed. Both "deformities" will have an inverted heel and both may have high lateral forefoot pressure. How do you tell the difference between them. (Does a rearfoot varus cause a forefoot valgus?) The key is available range of motion of the forefoot to lift off of the ground. A partially compensated rearfoot varus will use up all of the available subtalar joint range of motion to attempt to get the medial column on the ground. A forefoot valgus that causes supination of the STJ will have available range of motion of the STJ. This is how you tell the diference between the two. You place a block under the lateral forefoot and the rearfoot varus foot will not have calcaneal eversion, becasue none is available, and the forefoot valgus will show calcaneal eversion when standing on the block.

    Adding a valgus forefoot wedge under the partially compensated varus foot will hurt as you are trying to evert the foot further than its range of motion will allow.

    Cheers,

    Eric
     
  16. David Wedemeyer

    David Wedemeyer Well-Known Member

    Eric

    Thank you for that explanation of the Coleman Block Test. I have always had trouble verbalizing those concepts and putting them on paper, often having to look to a reference when I find this on a patients exam. I have no idea why this one simple test causes my brain to misfire and grasp for clarity. Your explanation is one that made much more sense to me than how it was initially presented and will be useful.

    Of course now I have to try and figure out the concepts in David's diagram. I could be at it for a long, long time.

    Regards,

    The neophyte :bash:
     
  17. David Smith

    David Smith Well-Known Member

    David W

    Think of this - A person lifts a 100kg rock to a height of 1metre. That person has 1000N of force applied thru their legs and acting on the ground. For equilibrium the ground must also push back (apply force) with the same force.
    Now that force is finite ie 1000N and so if two people now pick up the rock they share equally the load and so only 500N of force per person is applied by the ground to the feet. The rock is still at 1metre height.
    Substitute the people for foot structure (eg tendon) and orthosis and there you have it. The rock could be lifted higher if they chose to do so but 1 meter is all that is required. The tendon could, via the muscle, pull harder but the foot position is ok and so it does not need to. Muscle and tendon due to their dynamic nature do not have a fixed stress strain relationship, whereas ligaments do, within the limitations of their viscoelastic properties. Ligament and other passive structures must change length as the stress changes.

    Does this help?? :drinks Dave
     
  18. David Wedemeyer

    David Wedemeyer Well-Known Member

    David

    I am new to the tissue stress theories but I am beginning to glean the meaning as I read on here. That is helpful and it does make sense.

    Thank you

    Regards,

    David
     
  19. markjohconley

    markjohconley Well-Known Member

    Placing the heel only on a block would also differentiate them, no?
     
  20. efuller

    efuller MVP

    What the Block does is shift the location of center of pressure to a more lateral position. This will increase the pronation moment from the ground. If there is range of motion, then the STJ will pronate. There will generally be a longer lever arm at the forefoot than at the heel. There are some very rare feet in which the entire foot is medial to the axis and neither location would end up pronating the STJ. Theoretically, there could be a foot in which the block under the lateral forefoot would pronate the STJ and a block under the heel would not. This is not very likely.

    Of course if you ask the patient to evert, and they understand your directions, they will use their peroneal muscles to create a pronation moment and if there is range of motion they will pronate. So, you could see if there is range of motion without using the block.

    Eric
     
  21. markjohconley

    markjohconley Well-Known Member

    Goodaye Eric, what I was thinking is;
    by placing the block under the heel only, that takes away the external forces through the forefoot so if partially/uncompensated rearfoot varus then the rearfoot would remain inverted whereas in a foot with a rigid forefoot valgus the rearfoot would evert as the external pronatory moment from the medial forefoot would be eliminated. Is that what you said?, thanks, mark
     
  22. efuller

    efuller MVP

    Forces on the forefoot contribute to the total center of pressure. The further lateral the center of pressure is to the STJ axis the more likely you are to generate a pronation moment that will evert the foot if there is range of motion available to do so. So, there is no reason to eliminate the forces on the forefoot. All you want to do is create a large pronation moment to see if the STJ has range of motion to pronate.

    Eric
     
  23. markjohconley

    markjohconley Well-Known Member

    Thanks Eric for taking the time to reply,
    I comprehend what your saying, and if I was trying to differentiate between laterally deviated STJ axis and partially compensated rearfoot varus then the Coleman block test but if it's a rigid forefoot valgus then the forefoot grf wouldn't be needed, to differentiate, as there would be no retrograde inversion external eversion moments. Don't get me wrong I don't mind being proven wrong, look at all my previous biomechanical posts (not my climate change ones, can't understand the gullibility of some intelligent people not accepting science), all the best, mark
     
  24. efuller

    efuller MVP

    I believe that a rigid forefoot valgus has a laterally deviated STJ axis. The retrograde force from the forefoot is still dependent upon the location of the STJ axis. If the first met head is lateral to the axis force on the first met head will pronated the STJ and when the first met head is medial to the STJ axis, force on the first met head will supinate the STJ.

    Eric
     
  25. markjohconley

    markjohconley Well-Known Member

    Thanks, wouldn't the foot have the laterally deviated STJ axis as a result of the rigid forefoot valgus?
     
  26. efuller

    efuller MVP

    Now we are getting into philosophy. Some Root disciples classified forefoot valgus as rigid or flexible. A rigid one is one that compensates at the STJ and a flexible one is one that does not compensate with STJ supination. So the rigid forefoot valgus foot might be rigid because it has a laterally positioned STJ axis.

    Yes, in a more supinated STJ position the axis will tend to shift laterally. So there is some inter-relationship.

    Eric
     
  27. markjohconley

    markjohconley Well-Known Member

    Thanks Eric
     
  28. alaranjo

    alaranjo Member

    Hey everyone!

    I was reading all the posts and had some doubts. I had a patient with: pes cavus, forefoot valgus, with rearfoot varus compensating that forefoot, and hallux limitus (comproved by X-ray).
    I made him orthoses, for the cavus foot. In the beginning I tried only the cut-out and he said it hurt, then I tried elevating the 2-5th metatarsal heads and it hurt, the only solution I found was a cut-out with a pronated forefoot wedge from the 2-5th metatarsal heads. It was the only way I could make him comfortable and without pain. I know it sounds, I don't know "stupid", perhaps, but I tried everything, and I'm beginning to be frustrated with this, because it's probably overloading the forefoot... A little help please!

    Cheers,

    André
     
  29. efuller

    efuller MVP

    What is a pronated forefoot wedge?
     
  30. jasper1966

    jasper1966 Member

    Hi

    Has anyone either privately or within NHS podiatry come across the Salfordinsole prescription custom orthotic service? Seems they are very new to this facet of the game. (Salford insoles the giant full length plastic things are of course well known)Was wondering on quality of device provided service etc - in effect are they any good???

    Could anyone recommend a good outsource orthotic manufacturer - have used Salts/Stepahead and found them good but its always good to try others i suppose.

    Thanks
     
  31. Paul Bowles

    Paul Bowles Well-Known Member

    I think he means a valgus wedge 2-5....
     
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