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Pre-loading the hallux

Discussion in 'Biomechanics, Sports and Foot orthoses' started by Asher, Mar 8, 2007.

  1. Asher

    Asher Well-Known Member


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    Hi all

    A cluffy wedge is used to pre-load the hallux to engage the windlass mechanism earlier. But when there is significant hyperextension of the interphalangeal joint of the hallux, this elevates the distal phalanx and therefore toenail into the toebox of the shoe.

    So it would seem feasible to use material only under the proximal phalanx only, not the distal phalanx. That way you could use a thicker material and get earlier and easier windlass establishment.

    Has anyone had a go at this. Is there anything detrimental that could occur?

    Rebecca
     
  2. efuller

    efuller MVP

    I don't really see the need to engage the windlass earlier. Why do you think it should be engaged earlier? It will be engaged quite well in many feet as soon as the first met head bears weight and causes unwiding of the windlass. In many feet the plantar fascia is tight to palpation in static stance. In these feet it is already serving the function of resisting arch flattening moments and STJ pronation moments.

    Cheers,

    Eric Fuller
     
  3. Asher

    Asher Well-Known Member

    Hi Eric,

    In those individuals with a functional hallux limitus ie:delay in establishing the windlass or have larger forces required to initiate windlass, a cluffy wedge is just one tool that can be used. Putting the 1st MPJ in a degree of dorsiflexion reduces the establishement force required / brings it on earlier. I am recollecting from Craig Payne's seminars of 2006 in Australia.

    Some of these people with functioanl hallux limitus have a hyperextended hallux IPJ (ie: big toe curling up). While it would still be beneficial to use a cluffy wedge in these circumstances, there would be occasions where it would only add to the common problem of nail irritation within the shoe toebox.

    My thought was rather than not use a cluffy wedge at all in these cases (as a cluffy wedge extends the length of the hallux and elevates the whole toe), material could be placed only under the proximal phalanx. This provides dorsiflexion at the 1st MPJ but allows plantarflexion at the IPJ therefore not lifting up the distal phalanx.

    By elevating the proximal phanax, with the interphalangeal joint in its neutral (hyperextended) position, the IPJ will have to plantarflex and remain plantarflexed in a dynamic situation. I'm not sure whether this would be the case dynamically. So inspite of the distal phalanx physically being able to plantarflex to not irritate at the top of the toebox, does this actually occur.

    Rebecca
     
  4. Craig Payne

    Craig Payne Moderator

    Articles:
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    Eric, I use EVA under the hallux in those with a delayed onset to the windlass - never in those with a normally functioning. These are the people who's hallux can be dorsiflexed >10 or so degrees during static stance before tension in the windlass is felt. We still doing work to better qantify effects, but we can get a more rapid forward progression of the CoP in some those people in which the windlass is delayed.

    Rebbeca - in answer to your original question..... I don't know! - its still early days. We still doing experiments by always put it under the proximal phalanx.
     
  5. Asher

    Asher Well-Known Member

    I've been dabbling with this pad under the proximal phalanx of the first toe for a couple of days and I think it is definitely something to try for those with a hyperextended interphalangeal joint of the hallux ie: big toe curls up. It would be better than a cluffy wedge for this particular problem.

    I envisage a much thicker pad also (compared to the cluffy) could be used which will provide earlier and easier windlass establishment (compared to the cluffy) for a case of functional hallux limitus with hyperextended IPJ. Plus it will counter the hyperextended IPJ.

    I have a mild-moderate hyperextended IPJ (n=1!) and I have tolerated 6mm PPT added under the forefoot extension of my premade device positioned along the shaft of the phalanx. Previous to this, I have tried a 10 degree (EVA firm density) cluffy wedge which I didn't tolerate due to nail irritation.

    As far as I can see, it would be indicated for hyperextended IPJ due to functional hallux limitus where the IPJ is flexible ie: available plantarflexion range.

    You wouldn't want to use it if 1st MPJ dorsiflexion was contraindicated eg: painful structural hallux rigidus/limitus. I wouldn't use it unless the IPJ is hyperextended and unless there is a functional hallux limitus because I would imagine it might well cause a trigger first toe.

    What do you think?

    Rebecca
     
  6. drdebrule

    drdebrule Active Member

    I routinely use Cluffy wedges and have now made them an option for the orthotic lab I own in the United States. It appears one patient out of 10 can not tolerate the Cluffy: hallux IPJ hyperextended, hallux hammer toe, tight toe box, or reason unknown, females more than males at about 3:1 mabye. I don't really know anything detrimental that can occur, however the wedge does elevate hallux pressure in addition to 1st met head pressure. My lab has had some success by putting the Cluffy under a topcover to smooth out the transition.

    When a Cluffy fails or is not tolerated, just switch to a different orthotic option to treat functional hallux limitus.

    I hope that helps.

    Mike
     
  7. efuller

    efuller MVP


    Is delay in the windlass the same thing as having larger forces required to activate the windlass?

    I see two types of feet with FnHL (functional hallux limitus) in gait. Those with medially deviated STJ axes who will often require high forces to initiate the windlass mechanism and the fascia is often tight in stance before the hallux is lifted. The other type of foot is one that has a more laterally positioned STJ axis and has late stance phase pronation in gait. I would wager these are the feet with delayed onset of the windlass in static stance. However, I haven't looked closely at the correlation. I can theoretically see why these people would be helped with the wedge.

    The point being, don't immediately think FnHL = cluffy wedge. Maybe think delayed windlass = cluffy wedge.


    I like the reasoning above. Will it be comfortable?

    Eric
     
  8. The inventor of the "Cluffy Wedge" Dr. James Clough (pronounced "Cluff") was a classmate of mine in the CCPM Class of 1983 and practices in Montana here in the States. Through experimentation, Jim found that this wedge placed under the hallux helped some of his patients (as you can see in his webpage of testimonials at http://footandankleclinic.com/cluffy/pfv_wedge.html). He now has patented this little in-shoe device http://www.uspatentserver.com/687/6874258_c.html. Certainly, this type of wedge makes sense for some patients and I have tried similar types of sub-hallux wedges since talking to Jim a few years about his "Cluffy Wedge" invention. To me, the Cluffy Wedge is just another type of forefoot extension foot orthosis modification, like a 2-5 forefoot extension or a Morton's extension. I would be surprised if this type of sub-hallux pad has not been used in some shape or form for many years in the podiatric-pedorthist community, especially considering the fact that I have used Morton's extensions that extend plantar to the hallux on occasion for over 20 years. However, Dr. Clough's angular shape of his sub-hallux Cluffy Wedge certainly seems to be quite original, from what I have seen.
     
  9. Asher

    Asher Well-Known Member

    I've been using it as often as I can of late.

    Many people (majority) find it comfortable and the alignment of the distal phalanx is much improved so no shoe irritation.

    In some cases, although the alignment is great, they don't tolerate it - irritates the plantar surface corresponding to where the padding is, not the dorsum of the hallux. In my cases, these have been long distance runners and squash players so far.

    And in some (only a few at this stage), the pad just lifts the whole hallux up - no good. Mainly tight extensor tendon, older adult population and a few I can't work out why.

    Rebecca
     
  10. Asher

    Asher Well-Known Member

    You need a stiff forefoot extension material (eg: 1.5mm spenco too flimsy) otherwise it moves in the shoe and the position of the padding doesn't remain where it should be: has ended up lateral or under the 1st MPJ, due to the level and type of activity.
     
  11. Asher

    Asher Well-Known Member

    I have attached two pictures (hopefully) of the right foot of one subject who has a mild but troublesome hyperextended IPJ of the hallux.

    One without the prop, one with the prop.

    Notice the pitch of the distal phalanx / nail is reduced with the prop.

    Admittedly, not all cases result in a reduction of the hyperextension (as explained in earlier post) but its worth a try in individuals with this problem.

    Rebecca
     

    Attached Files:

  12. Asher

    Asher Well-Known Member

    Patient has significantly hyperextended hallux interphalangeal joint bilaterally.
    Quite symptomatic under the IPJ and distal nail.
    Very active: Long distance runner, hockey, squash
    Prop under the prox phalanx (attached to orthotic extension) has negated all symptoms and is comfortable to wear.
    Look at the position of the distal phalanx on the left image with / without the prop.

    Rebecca
     

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  13. Just stumbled across this one.

    Sorry, i'm having a dense moment. Could some kindly person explain to me how this works?

    [​IMG]

    [​IMG]

    I can see how engaging the windlass early could help for late stance pronation. I can't see how dorsiflexing a toe with limited dorsiflexion will unlock the big toe.

    I'm also a bit confused as to the difference beween increasing the sagital angle of the 1st mpj by putting a wedge under the toe and increasing the angle by putting a raise under the heel.

    If this is obvious to everybody else then my apologies. I just can't grasp it :craig:.

    Has there been any research on this?

    Thanks
    Robert
     
  14. Craig Payne

    Craig Payne Moderator

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    It dosen't. If there is a structural hallux limitus, it won't help (and may be even be detrimental). If there is a functional hallux limitus, its does tend to "unlock it" (the "unlock" is marketing speak from the product promotor). It does appear that if the MPJ is in a slighlty different position, then the functional block just does not seem to occur (at least that is what you see in the pressure mapping and is one theory to expain what is seen)
    There is no difference. When the windlass is delayed, there is only one way to bring it on earlier --> change the sagittal plane angle at the first MPJ (as you said). This can be done in one of two ways: elevate the heel and/or elevate the hallux. I assume it does not matter which one you do or if you do both. Footwear will constrian the amount that could be done with either (ie 3/4mm is often all you can get under the hallux)
     
  15. Now i'm even MORE confused :hammer:

    FHL does not "unlock" in the first 5 degrees (or so) of heel raise during gait. How, then, does dorsiflexing the toe and putting the joint in that position "unlock" the toe? What, in fact, do we mean by "locked" and "unlocked"?

    Still struggling...
    4 mm under the hallux. Distance between my ipj and mpj is about an inch. Distance between my Mpj and heel is about 5. Meaning to obtain the same angle you would need about 20mm under the heel to acheive the same angle, (assuming my maths is right, its late here.)

    I can see how that would be easier with the wedge in mens shoes in particular. That bit now makes sense. Thanks :drinks.

    Regards
    Robert
    :sinking:
    ***************
     
    Last edited by a moderator: Mar 1, 2008
  16. Craig Payne

    Craig Payne Moderator

    Articles:
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    I have no idea.

    The whole concept of functional hallux limitus is a theoretical construct to explain what appears to be a temporary functional block in hallux dorsiflexion. If this block is present, there are characteristic features on pressure mapping (though other theoretical constructs could possibly explain what is also seen). If something is done to preload the hallux (or any of the other modalities used for FnHL), the pressure mapping pattern usually changes to what could be considered a more normal pattern. It happens. .... no doubt about it.

    The concept of functional hallux limitus and sagittal plane theory are nothing more than good theoretical constructs to explain what is seen and many people miss that - they are not "facts". I am not even sure functional hallux limitus exists - if we pretend there is such a thing, then its very useful to explain a lot of what we see. (I coined the phrase "convenient theoretical fiction" in the context of the 2 axes mtj model and the phrase is equalbly applicable here)

    The whole concept of "locking" and "unlocking" is more marketing speak as it just sounds plausible and is a good way to sell a product (and talk to patients). Maybe we should be talking about a temporary increase in dorsiflexion stiffness at the first MPJ. That temporary incrase may be due to osseous shape; soft tissue constraints; proximal influences; etc. If we assume that this is the case, then theoretically what preloading the hallux is doing could be:

    1. Bring windlass on earlier if its delayed (is it harmful if its not delayed?)
    2. "Unlocks" a functional hallux limitus (if FnHL is "locked" - but as you said, how does it do that?)
    3. The change in hallux angle, reduces the temporary increase in dorsiflexion stiffness at the first MPJ (does this sound a more plausible explanation that "unlocking"?)

    The whole indication for the Cluffy Wedge (a trade name for a product aimed at preloading the hallux) is marketed by its developer for functional hallux limitus and NOT structural hallux limitus. Its a shame that those who choose to bag the product can't distinguish between FnHL & SHL and use the concept of SHL for their criticism.

    The Cluffy Wedge was NOT marketed for bringing the windlass on earlier; the concept of it being used for a delayed windlass is something that has evolved out of a better undertsanding on the many dysfunctions of the windlass mechanism. I am not even sure if Dr Clough is even aware of this indication for the Cluffy Wedge.

    ...hence the term "Preload the hallux" rather than use a commerical name for the concept.
     
    Last edited: Mar 1, 2008
  17. Trent Baker

    Trent Baker Active Member

    Craig,

    My understanding is that there are several techniques for 'preloading the hallux', other than the Cluffy Wedge. Perhaps you could indicate which technique is more efficient in achieving this and therefore possibly better at inducing Windlass.

    For a few years now I have been using an alternative to a first ray cut out. I found a few problems with a cut out as they are generally uncomfortable. So I started using a technique where by a 3mm poly device is thinned out through the first ray. Gradually taking it from 3mm to 2mm then 1mm reducing the rigidity of the device under the first ray. While reducing subtalar joint pronation using a medial extrinsic post and flexing out the first ray of the device (much the same as a cut out) the 1st met plantarflexes there by preloading the hallux.

    Would this be as equally efficient as a Cluffy Wedge? If so, this techique should reduce the problems associated with toe box crowding associated with a 4mm Cluffy Wedge, a problem earlier noted by Rebecca. Could this technique even be used in conjunction with heel elevation to increase it's efficiency?

    Regards
    Trent
     
  18. Craig Payne

    Craig Payne Moderator

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    Trent, you are talking about something different.

    When there is an inadequate/inappropriate load on the first metatarsal head, there are many strategies to attempt to get that towards what would be considered a normal pattern. A first ray cut is one way to achieve that; an orthotic more flexible under the medial coloumn is another way; a 2-5 bar is another; etc ; preloading the hallux is another way.

    The whole concept of preloading the hallux is to load the hallux sooner than it would normally load (ie "preload") to achieve some mechanical effect (a first ray cut out dosen't preload the hallux).

    Anything under the hallux will preload it - padding or wedging under the hallux; a Kinetic Wedge(TM); a Cluff Wedge(TM) ...
     
  19. Trent Baker

    Trent Baker Active Member

    Thanks Craig, I undertsand the difference now. Am I still correct in saying that the two things are aimed at achieving a similar outcome, ie. inducing Windlass??

    Could you recomend some research papers on this subject to enhance my understanding?

    Trent
     
    Last edited: Mar 2, 2008
  20. Craig Payne

    Craig Payne Moderator

    Articles:
    8
    Sort of ... there are several potential dysfunctions of the windlass (some I am not sure even exist). Different orthotic design parameters have different potential effects on windlass function. Possible dysfunctions include:
    1. Delayed onset to windlass
    2. High force to establish
    3. Disruption during loading/uneven loading
    4. No windlass

    Preloading the hallux will potentailly help with (1) and maybe (2). A first ray cut out or anything that facilitates first ray plantarflexion certainly lower the force to establish the windlass (ie make it easier to get established), so they help with (2).

    As for (3), thats anyone guess, but you could take a guess that this might be FnHL. For (4), the best option is to refer those people to your enemy, so they cause them rather than you some grief.
    Not really ... just keep reading here as I am sure it will get posted as soon as published.
     
  21. Trent Baker

    Trent Baker Active Member

    So the key with windlass function is to establish the specific dysfunction, then apply orthotic design where appropriate.

    Then again you could cover the bases by combining two elements within a device that would both preload the hallux and facilitate first ray plantarflexion, which would ultimately give the best result possible given the most up to date research. Although in case of dysfunction (4), I have a few people in mind for referral :)

    This is great Craig. I appreciate the time you take to answer these questions.

    Regards
    Trent
     
  22. Craig Payne

    Craig Payne Moderator

    Articles:
    8
    ...which is exactly what the Kinetic Wedge(TM) does.
     
  23. Trent Baker

    Trent Baker Active Member

    There you go, still learning even more on a Sunday arvo. Thanks again.
     
  24. Robert, Craig, Trent and Colleagues:

    First of all, Robert, I never become worried about not being able to understand what is said in an advertisement of a product since advertisements often times are not true.

    James Clough, DPM, (pronounced "Cluff") was a classmate of mine from the CCPM class of 1983. He invented the Cluffy Wedge (CW) which is currently being marketed as "unlocking the big toe joint". Before Jim brought the CW to market, he asked me about it and I was somewhat impressed with the slight decrease in pronation that the wedge produced on videos he showed me of his patients with and without the CW.

    The CW functions by dorsiflexing the hallux which increases the tensile force within the medial slip of the central component of the plantar aponeurosis which, in turn, will cause a first ray plantarflexion moment, a medial column plantarflexion moment and a rearfoot dorsiflexion moment, assuming the plantar aponeurosis is intact. The CW has the potential to slightly supinate the foot, given the right conditions in the foot, but the CW may not always supinate the foot, especially in a foot with a more medially deviated STJ axis or significantly decreased medial longitudinal arch height. In fact, the CW may cause plantar fasciitis by increasing the tensile force within the plantar fascia, especially if the foot does not supinate in response to the CW.

    Now, on to the advertisement. I don't understand how the CW "unlocks the 1st MPJ". First of all, like Craig said, the terms "locking" and "unlocking" are imprecise and ambiguous terms that should not be used to describe the kinetics or kinematics of any joint of the body. The CW may have the potential to allow more hallux dorsiflexion during propulsion in some individuals, and thus help reduce functional hallux limitus (FnHL), but would not have any effect in other individuals.

    FnHL is really fairly easy to understand if you simply realize that FnHL is a condition that occurs when the internal 1st metatarsophalangeal joint (MPJ) plantarflexion moments are greater than the external 1st MPJ dorsiflexion moments from ground reaction force (GRF) acting plantar to the hallux. The plantar soft tissue structures, such as the plantar aponeurosis, flexor hallucis longus/brevis, and abductor/adductor hallucis muscles all cause increased 1st MPJ plantarflexion moment that will restrict hallux dorsiflexion and cause FnHL to occur in some individuals. A decrease in medial longitudinal arch (MLA) height and an increased medial deviation of the subtalar joint axis will greatly increase the tendency for FnHL to occur.

    I disagree with Craig that the condition of FnHL is a "theoretical construct". FnHL is a real phenomenon that can be demonstrated both in the non-weightbearing and weightbearing foot and was first described in the medical literature by one of the former biomechanics faculty at CCPM, Patrick Laird, DPM, in 1972 (Laird PO: Functional hallux limitus. The Illinois Podiatrist. 9:4, 1972). What is a theory is that FnHL causes foot pronation. The theory that FnHL causes foot pronation is taught by the followers of the Sagittal Plane Facilitation Theory. I don't agree that FnHL causes foot pronation. Foot pronation, rather, causes FnHL since foot pronation will directly increase the tension within the medial slip of the plantar fascia, increase the 1st MPJ plantarflexion moment and decrease the chance that normal hallux dorsiflexion will occur during propulsion.

    I have used the CW previously, but currently don't use the CW. Rather, I will sometimes use a piece of 1/8" (3 mm) adhesive felt under the hallux on the orthosis in some individuals. Sometimes it helps make the patient walk better and feel better, sometimes it doesn't. However, for FnHL I have found that the most reliable way to increase the 1st MPJ dorsiflexion during gait is to to decrease the first ray dorsiflexion moments from GRF by using a 2-5 forefoot extension, along with increasing the subtalar joint supination moments by using a medial heel skive and increased MLA height and along with increasing the medial forefoot plantarflexion moment by increasing the MLA height of the orthosis. I would consider the CW to be far down on the list of techniques I would use to increase hallux dorsiflexion during propulsion but may consider its use to increase the supination of the foot in some types of feet. The CW does have the benefit of being easy to apply to an insole/orthosis and easy to remove if it doesn't work.

    It would probably be helpful if David Smith chimed in here since I know he recently completed his Master's research project on 1st MPJ and MLA lengthening and their mechanical coupling. FnHL is not hard to understand, as long as you try to understand it using basic mechanical and engineering principles.

    Hope this helps.
     
    Last edited: Mar 2, 2008
  25. Huge thanks to craig and Kevin. That makes a lot more sense now.

    On another note that was the BEST explanation of FnHL i have EVER seen.:good:

    Cheers guys!

    Robert
     
  26. David Smith

    David Smith Well-Known Member

    Kevin wrote
    In my MSc research I attempted to do an in vivo study of the hallux windlass and its effect on the MLA integrity and plantar fascia tension, stress and strain and how this related to FncHL.

    This is my expanded conclusion to the above.


    For optimal progression of the foot through the saggital plane and to avoid Functional hallux limitus is appears that after heel lift and as the hallux dorsiflexes there should be decreasing dorsiflexing moments, applied by hallux and 1st MPJ GRF, about the NCJ.

    Functional Hallux Limitus exists when the MLA excessively extends and lowers after toe contact at 33% stance and before heel lift at 57% stance. The relative increase in PF tension, due to the windlass action, increases the stiffness of the Hallux Plantarflexion reaction to dorsiflexing GRF. This in turn results in a longer moment arm for the 1st ray and a shorter moment arm for the plantar fascia to act on the NCJ. This culminates as increasing dorsiflexion moments about NCJ after heel off.

    It appears that the correct progression of plantar pressure sub 1st MPJ and sub Hallux is inhibited when this situation occurs and early and high-pressure sub Hallux is seen. It appears then, that FncHL follows lowering of the MLA, then dysfunctional plantar pressure progression develops with FncHL. As proposed by Dananberg et al (2,12) this sequence of events results in slowing of the sagittal plane progression of the CoM due to increased GRF dorsiflexion moments about the TCJ and a corresponding increase in Achilles Tendon tension (46-48), which retards the forward motion of the tibia.

    As stated it is thought FncHL exists when GRF acting on the hallux and 1st MPJ result in increasing dorsiflexion moments about the NCJ of the lowered MLA. However it may be that it is progressive in nature in that the Hallux RoM is increasingly limited by its increasing stiffness to GRF due to increased PF tension. However because the PF becomes much thinner at the insertion most of the PF extension occurs here and therefore Hallux dorsiflexion and forward progression can be maintained within certain limits of PF tension. Further research is required to establish the exact point that could be identified as FncHL if indeed an exact point exists

    Data collected and analysed from RS Scan pressure mat and Kistler force plate may show an indicator for normal HW action without significant FncHL. It indicates that total peak forefoot GRF should occur after Heel off (HO) and before peak sub Hallux force. If Peak f/f GRF coincides with or succeeds peak sub Hallux force then significant FncHL will occur. This theory will require further research to confirm but has been similarly proposed by Gheluwe and Dananberg et al 2006 (2)

    When the Cuffy wedge is applied it will then encourage early dorsiflexion of the hallux and pre tensioning of the plantar fascia. Therefore the lowering of the MLA will be stopped slightly earlier in the stance phase and optimally, well before heel lift. Without the wedge the toe windlass can unwind a little more and so allow more lowering of the MLA which perhaps will continue well after toe contact and before or even after heel off and become low enough to allow FncHL as explained earlier.

    The material characteristics of the plantar fascia may be the reason why the CW may not work on some subjects. Even with the pre tensioned plantar fascia the material properties of the plantar fascia particularly at its thin insertion, which has a lower strain / coefficient (N/mm) i.e. it stretches more easily, may allow the MLA to lower to the point where FncHL occurs.

    All the best Dave
     
    Last edited: Mar 3, 2008
  27. Dave:

    Thanks for that.
     
  28. Trent Baker

    Trent Baker Active Member

    Just thought I would let you know that I tried adding a Cluffy Wedge to an existing orthotic patient today.

    The patient originally presented with classic plantarfasciitis on the right foot. Lady in her 50s walks daily, retired, wears appropriate footwear. Tight gastroc/soleus on the right leg reducing ankle joint ROM. Tib'post' dysfunction with the right foot significantly more pronated than the left at STJ and subsequent midtarsal joint compensation causing MLA collapse, medial bulge. In short right foot FPI of +10, while left foot FPI of +4

    The patient was placed on ice/massage/stretching regime in conjunction with poly Mod Root devices with right 5degrees varus rearfoot, extrinsic post and flexible first ray (similar idea to a cut out). The patient found these comfortable and within 8 weeks the symptoms were 80% resolved and 100% within 6 months.

    I reviewed her today another 12 months down the track. Although still asymptomatic the right foot was experiencing irritation over the MLA where the medial apsect was bulging over the device. With hind sight perhaps a medial flange might have helped in the original prescription. Non the less the patient was still pretty happy with the results but was not wearing the orthoses as much due to the right MLA irritation.

    I added a full length cover with a reverse Morton's extension and a Cluffy wedge, I have to say that even statically the postural change was significant enough for both of us to notice. The patient tried the device in shoe and reported reduced irritation immediately.

    I know this won't work for every patient, however I have to say I was surprised at the postural change. I guess I'll try it again when appropriate. Thanks to all of you for the information in this thread.

    Trent
     
  29. Bruce Williams

    Bruce Williams Well-Known Member

    Outstanding Dave!
    Bruce
     
  30. David Smith

    David Smith Well-Known Member

    well thank you Bruce
     
    Last edited: Mar 4, 2008
  31. David Smith

    David Smith Well-Known Member

    Hmm! Just had a thought:confused:

    If the MLA in one foot lowers more than another will this result in delayed heel lift or does the MLA reach the max extension / lowering at the same time in both feet. Therefore the MLA extension velocity would be higher in the foot with the lower arch. Certainly we often see delayed heel lift in the closed Kinetic chain low arched foot but this may be due to the effects of FncHL reducing CoM velocity.

    What do you think?

    How atagonistic to the plantar fascia is the EHL muscle. If it was very antagonistic then this may delay arch lowering and reduce FncHL? If it was not very antagonistic would this tend to lead to FncHL in these types?

    With this in mind could we elaborate on the cluffy wedge and add some mechanism that increases the plantarflexion stiffness but not reduce the RoM of the 1st MPJ EG like a flexible sprung extension from an orthosis under the hallux.

    Would a shoe with a high toe spring achieve this?

    Your thought would be appreciated.

    Cheers Dave
     
    Last edited: Mar 4, 2008
  32. efuller

    efuller MVP

    Do think it was the wedge or the top cover? I usually order xtra wide orthotics on the side of the unilateral flat foot so that the don't hang over the edge. Don't worry about the shoe being damaged by the wide orthotic, the foot will soon damage the shoe itself.

    Eric
     
  33. efuller

    efuller MVP

    Heel lift is caused by ankle plantar flexion moment. It's not caused by CoM velocity. When heel lift occurs the pivot point can be at the 1st IPJ, the MPJ the 1st met cuneiform joint, etc. The location of the pivot point will be determined by the relative stiffness at all of the pivot points. Often with FnHL you will see hyperextension of the IPJ.

    In gait as the tibia rotates over the stance foot there has to be a plantar flexion moment at the ankle joint for the heel lift. The plantar flexion moment can be caused end of range of motion of the ankle (the talar neck hits the tibia) or by tension in the achilles tendon.

    So, to delay heel lift you have to choose to walk slower so that you don't reach the end of ROM sooner or decrease activation of the gastroc and soleus muscles to decrease the plantar flexion moment at the ankle, or a combination of both of those.

    I agree that you will often see a slow progression of the center of mass with FnHL, but I don't necessarily think the relationship is directly one caused by the other. My theory is that if you have a pivot point, like the IPJ, that hurts to pivot around, you will choose to walk slower and with less muscular plantar flexion moment.

    Well, tension in the platar causing a planar flexion moment is directly antagonistic to tension in the EHL tendon causing a dorsiflexion moment. However, the question is how often do you have tension in the plantar fascia at the same time you hve tension in EHL. Hicks stated that the windlass mechanism has much greater leverage than any muscle. The amount of moment from EHL is propably quite small in comparison to the dorsiflexion moment from the ground at heel lift. I don't have numbers at the finger tips but ground reaction force on the hallux could be as high as 1/3 body weight and this would be causing a dorsiflexion moment at the MPJ.

    More on EHL: EHL is a direct arch flattener as it passes above the bones of the arch. When contracts non WB you will see arch rasining because dorsiflexion of the hallux will cause the windlass to plantar flex the 1st ray.


    Plantar flexion stiffness of ...?

    If the shoe was stiff enough and had high enoug toe spring it could work like a cluffy wedge. My take on the cluffy wedge is very similar to Kevin's. With pre-dorsiflexion of the hallux you will not be able to pronate as far before tension in the plantar fascia stops pronation. So, you may achieve a more supinated position with the cluffy wedge, but you may not necessarily reduce tension in the plantar fascia. To stop proantion, for example during gait, something or some things has/have to apply a supination moment. If before the wedge, pronation is stopped by the floor of the sinus tarsi and some tension in the plantar fascia. Then, after the wedge, pronation could be stopped entirely by tension in the plantar fascia and this would be a dramatic increase in tension in the fascia.

    cheers,

    Eric Fuller
     
  34. Another way by which to delay heel lift for an individual is to decrease the forefoot dorsiflexion stiffness of the foot so that the forefoot will dorsiflex more on the rearfoot during late midstance. This could be accomplished somewhat by decreased activation of the deep flexors and/or peroneus longus and/or plantar intrinsic muscles. Certainly, however, in comparing one individual's foot to another individual's foot, a delay in heel lift can very clearly be caused by interindividual variation in forefoot dorsiflexion stiffness (i.e. lower forefoot dorsiflexion stiffness). By the way, feet with decreased forefoot dorsiflexion stiffness are often the same feet that develop functional hallux limitus.

    Below is a model I used in my PFOLA lecture last year of how these muscles and plantar fascia causes a forefoot plantarflexion moment which will increase the forefoot dorsiflexion stiffness during weightbearing activities.
     
  35. Dananberg

    Dananberg Active Member

    Plantarflexing the 1st met head or dorsiflexing the proximal phalanx of the hallux accomplish the same end...permitting earlier onset hallux dorsiflexion. My concern about the Cluffy Wedge is that it may excessively dorsiflex the hallux and cause superior hallux pain. Barefoot...using 1/8" felt sub hallux (as Kevin suggested) works great...just too thick to be effectively utilized in a normal depth shoe.

    Howard
     
  36. james clough DPM

    james clough DPM Active Member

    Even though this thread is old, I thought I would post a piece to the thread on my latest findings with pre- stressing the hallux in dorsiflexion and the effect this has on foot function. I am relatively new to Podiatry Arena. Sorry about the delayed post here.

    First of all I would like to point out how common this condition is, about 86% of my patients with foot pain present with this disorder. I will be publishing these results soon. This is not a rare phenomenon at all and I believe it is essential for proper foot function to address this component of mechanical foot pathology.

    Addressing rearfoot pronation, when present, is important to minimize the impact of medial colunm overload on first ray elevation. It is primarily elevation of the first ray that causes FnHL to begin with. I am sure you are familiar with the techniques of controlling the rearfoot and enumerated in Dr. Kirbys' post.

    As far as the etiology of this disorder, my surgical experience seems to suggest a correlation with the medial collateral ligament acting as a tension band to pull the hallux downward in plantarflexion. This restricts dorsiflexion of the joint only during weight bearing as this is when the first metatarsal elevates and changes the direction of pull on the medial collateral ligament, essentially changing the origination point of the ligament. By prestressing the hallux in dorsiflexion you eliminate the ability of the first metatarsal to elevate with respect to the proximal phalanx.

    As far as the first ray control is concerned you basically have the first ray cutouts, including the reverse mortons extension, or, prestressing of the hallux in dorsiflexion. I believe this latter method to be the superior approach of controlling first ray function, as you are not transferring weight to the lesser metatarsals as takes place with other methods. It is also important to allow the first metatarsal to bear weight in propulsion, and I question the logic of putting a cutout under the first metatarsal, wondering if this would delay the weight bearing of trhe first met? No one has adequately answered this question, but the logic here, I believe, is sound and the question certainly needs to be raised.
    I have used pre-stressing the hallux in dorsiflexion for about 7 years now and have used this literally on thousands of feet. I find that this augments our treatment of most every problem we would use an orthotic or insole for in the first place. In addition, I feel it is essential to control this pathology effectively to see better outcomes with our orthotic or OTC insoles.
    I have seen excellent results with this intervention with plantar fasciits, lesser metatarsal overload, neuroma pain, lateralization of forefoot loading and keratomas on the lateral forefoot, flexble hammertoe deformity, some bunion pain (when functional jamming of the joint occurs), achillodynia (both insertional problems as well as tendon disorders), PTTD, cuboid subluxation, peroneal tenosynovitis, as well as all the suprastructural problems normally associated with excessive internal leg rotation. Employing this method is sometimes the difference between success and failure with orthotics.

    Another observation I have made. It is sometimes possible to address many of these problems with pre-stressing the hallux in dorsiflexion without incorporating any rearfoot control. A wedge under the hallux is all that is needed in the absence of significant rearfoot pathology. Once the windlass is functioning properly, the foot can stabilize itself correctly moving forward in propulsion. In my experience this is a large number of patients presenting to my office. In this situation an OTC insole is a practical device used in transferring this correction from shoe to shoe.

    Please see the video on how this works at : http://www.youtube.com/watch?v=Gn7UqZDX0yM. Also the video on how to identify and overcome FnHL may be helpful at : http://www.youtube.com/watch?v=1U42frPYHH4
     
  37. Peter1234

    Peter1234 Active Member

    Hi
    What about lateral heel posting with a raised medial arch height, theoretically you should be able to initiate the windlass at an earlier stage in gait!?
     
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