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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?
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
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.
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.
I don't really see the need to engage the windlass earlier. Why do you think it should be engaged earlier?
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.
__________________ Craig Payne
__________________________________________________ ___________________________________ Follow me on Twitter | Run Junkie God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.
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.
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.
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..
Quote:
Originally Posted by Craig Payne
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.
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.
Quote:
Originally Posted by Asher
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
I like the reasoning above. Will it be comfortable?
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
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.
__________________
Sincerely,
Kevin
**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College
I like the reasoning above. Will it be comfortable?
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.
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.Rebecca
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.
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.
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.
Sorry, i'm having a dense moment. Could some kindly person explain to me how this works?
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 .
I can't see how dorsiflexing a toe with limited dorsiflexion will unlock the big toe.
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)
Quote:
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.
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)
__________________ Craig Payne
__________________________________________________ ___________________________________ Follow me on Twitter | Run Junkie God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.
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)
Now i'm even MORE confused
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...
Quote:
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)
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 .
Regards
Robert
***************
Last edited by Admin : 1st March 2008 at 04:03 PM.
Reason: whoops - no edit - pushed wrong button
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"?
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.
__________________ Craig Payne
__________________________________________________ ___________________________________ Follow me on Twitter | Run Junkie God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.
Last edited by Craig Payne : 1st March 2008 at 05:22 PM.
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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?
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) ...
__________________ Craig Payne
__________________________________________________ ___________________________________ Follow me on Twitter | Run Junkie God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.
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 by Trent Baker : 1st March 2008 at 11:56 PM.
Am I still correct in saying that the two things are aimed at achieving a similar outcome, ie. inducing Windlass??
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.
Quote:
Could you recomend some research papers on this subject to enhance my understanding?
Not really ... just keep reading here as I am sure it will get posted as soon as published.
__________________ Craig Payne
__________________________________________________ ___________________________________ Follow me on Twitter | Run Junkie God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.
The Following User Says Thank You to Craig Payne For This Useful Post:
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.
SThen 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 is exactly what the Kinetic Wedge(TM) does.
__________________ Craig Payne
__________________________________________________ ___________________________________ Follow me on Twitter | Run Junkie God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.
Sorry, i'm having a dense moment. Could some kindly person explain to me how this works?
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 .
Has there been any research on this?
Thanks
Robert
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.
__________________
Sincerely,
Kevin
**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College
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.
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 by David Smith : 3rd March 2008 at 03:01 PM.
Reason: expand abbreviation and add a bit
The Following User Says Thank You to David Smith For This Useful Post:
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Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College
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.
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.
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.
Pre-loading the hallux
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Linear Mode
