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Common problem unusual presentation - Stumped!!

Discussion in 'Biomechanics, Sports and Foot orthoses' started by David Smith, Jan 20, 2012.

  1. David Smith

    David Smith Well-Known Member

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    Hello All

    You know that thing where you wait for a bus for hours and then 4 come along at once, that thing where you see something odd and unusual and then three more people come in with it that weeks??

    Well recently 4 people have come into my clinic with a common complaint but with unusual presentation and it's stumping me a bit as to what sort of orthotic design and treatment program I should prescribe.

    The complaint is in all four cases plantar facsiitis, no doubt that this is the diagnosis, pain along the PF band as the hallux is dorsiflexed and it tensions and pressure is applied to the PF along its length and particularly painful to pressure on the medial tubercle of the calc.

    Open chain, the STJ axes are very lateral, STN is inverted with normal RoM. The forefoot is slightly valgus, the 1st ray is compliant but the MPJ is not low. The feet are fairly cavus open chain but have compliant midfoot joints, so the long arches are able to displace significantly if so loaded.

    In stance the feet/STJ are supinated and have very light supination and jacks test.
    In gait the feet supinate in heel strike to early stance, pronate from a supinated position in mid stance and supinate in late stance/propulsion. Ankle RoMs were similar in nature but none were very equinus or stiff although they all could be better and were improved with Mobs. None appeared to be using the peroneals excessively or out of normal phase but this is difficult to assess, and none had any peroneal pain.

    None of them were serious runners if at all, although all of them would run/jog or run/jog more if the feet didn't hurt. All of them had post static pain, which eased with walking but got worse again with long walks. They all had mid to forefoot strike in running gait with large range of pronation from inverted forefoot strike to pronated propulsive phase.

    AM3 pressure mat scans do not indicate significant saggital plane progression perturbation although 2 do appear to have some indication of FncHL in late stance phase but the total medial forces (taking into account the light supination / jacks test) applied to the foot and 1st MPH would be relatively low one might assume.

    So two problems here:

    1)What mechanism is causing the stress,? Why do they have plantar Fasciitis in the first place when they seem like unlike candidates who would not seem prone to such excessive stress in those tissues.

    2) What design of orthosis can I use, I’m not sure about the mechanism and anything that supinates the foot will likely cause inversion sprains.

    Regards Dave Smith
  2. David Wedemeyer

    David Wedemeyer Well-Known Member

    David is the heel in varus or does it correct somewhat in weight bearing? Is there Equinus? Is the first ray plantaflexed (mildly)?
  3. David Smith

    David Smith Well-Known Member

    In gait, Varus heel strike that supinates at first then pronates during midstance, in stance the heel remains varus.

    Mild equinus to normal RoM across the 4 subjects

    First ray not significantly plantarflexed

    Oh yes one more thing three of them had self prescribed gel heel cups that did not make much difference

    Cheers Dave
  4. David Wedemeyer

    David Wedemeyer Well-Known Member

    David at the risk of sounding pedantic and to someone with a great deal more knowledge than myself, I'd like to suggest that you may be over thinking this? It sounds like a compensated forefoot valgus in a high arched, flexible foot? Did you consider a Coleman Block test?
  5. David Smith

    David Smith Well-Known Member


    Really grateful for your replies thank you. You know when sometimes you can't see the wood for the trees well then its good to discuss with someone with a fresh mind, even if it does look a bit dumb, it resets the brain.

    Anyway no I haven't used a Coleman test but the 1st ray is not low or stiff enough to cause supination and supination is coming from the fact that the STJ is lateral and the fore foot is a little valgus.

    Are you thinking that is the foot is supinated by the low and stiff 1st ray that the GRF sub 1st MPJ that causes supination moments about the STJ will also plantarflex the 1st ray and stress the PF?

    Sorry not to quite understand your terminology, I came into biomechanics at the end of the nineties and from a different direction than thru the usual podiatric biomechanical education and so I didn't get so much Rootian foundation (even though I've read his work) and don't tend to use those classifications like 'compensated forefoot valgus' and uncompensated reafoot varus' I find them a little vague and imprecise but sometimes they can be useful to describe a whole concept in one sentence.

    Please keep on helping, its good to talk:drinks

    Regards Dave
    Last edited: Jan 21, 2012
  6. David Wedemeyer

    David Wedemeyer Well-Known Member


    We share the commonality that neither of us was traditionally trained in Root theory, I was exposed to it initially through pedorthic training. I had to struggle a lot with new information when I found PA. Then my head exploded. ;)

    I believe that I have already made a mistake in rereading my post. What you are describing is possibly a partially compensated or uncompensated foot. I’m not sure how relevant such a description is anymore being that I find most feet have a small degree of rearfoot varus and that we know that foot posture does correlate well with pathology. With all of that my suggestion may be lacking but I would concentrate on their gait, especially late stance phase.

    How certain are you that they supinate in late stance? I don't recall seeing many feet that supinate in late stance where the patient presented with PF. That is odd. What I have learned is that late stance phase pronation can occur in those with a laterally deviated STJA. Eric has written about this somewhere on here and I tend to listen carefully when Eric writes. I believe that he said they use their muscles to achieve this to avoid inversion sprains and that you would treat this person differently because the pronation is not caused by the ground (GRF) and that a lateral forefoot wedge would decrease late stance pronation in these presentations. I really struggled with the idea of a lateral forefoot wedge for PF but Eric's contributions really helped me to understand how useful this concept can be after working through my initial confusion.

    I hope Eric sees this and corrects any mistakes I may have made, be great to have his input in this discussion. I tend to rely more now on the presenting complaint, affected tissue, loaded foot and gait analysis to make my decisions for the orthosis than just unweighted observations. We have to consider more than just architecture and muscle influence I feel is often overlooked. This is classic tissue stress for me and precisely why typing feet is a huge step backwards as kinematic observations do not always produce the answers we are seeking. That said the mildly varus heel/valgus forefoot may be less of a factor in this case?

    So it may be counterintuitive that a foot with a laterally deviated STJA would pronate but I believe that we have to consider other factors contributing to the motion of that foot. With a forefoot valgus/rearfoot varus that would be the midtarsal and subtalar joint ROM, flexibility, toss in multiple joint axes and solving the problem becomes more challenging. Add muscular influence and you have a confusion Bouillabaisse!

    Please tell me these patients pronate in late stance or I may lose it!

    Enjoying this discussion, I miss just discussing biomechanics on PA. I always enjoy reading your posts David, you’re truly one of the brilliant thinkers on PA so please post more frequently?

    Best regards,
  7. Dave and David hope I am not butting in, but I have the same foot type and same symptoms discribed except the triceps surea - I have increased stiffness.

    Anyways - reduce the effect of the forefoot dorsiflexion moment Dave, add a cuboid notch to a high arch no rearfoot device - works for me.

    Back to normal posting
  8. Dave:

    The beauty of Tissue Stress Theory is that we don't need to actually know what "type of foot deformity" the patient possesses in order to determine the cause of the pain. In this regard, what do we know about the biomechanical function of the plantar fascia (i.e. the central component of plantar aponeurosis)?

    1. During weightbearing activities, the plantar fascia is under considerable tensile force, probably at a maximum of one times body weight of tensile force during walking (Erdimir A, Hamel AJ, Fauth AR, Piazza SJ, Sharkey NA: Dynamic loading of the plantar aponeurosis in walking. JBJS, 86A:546-552, 2004).

    2. Increases in Achilles tendon tension will also cause an increase in plantar fascia tension (Erdimir A, Hamel AJ, Fauth AR, Piazza SJ, Sharkey NA: Dynamic loading of the plantar aponeurosis in walking. JBJS, 86A:546-552, 2004; Carlson RE, Fleming LL, Hutton WC: The biomechanical relationship between the tendoachilles, plantar fascia and metatarsophalangeal joint dorsiflexion angle. Foot Ankle Intl., 21:18-25, 2000).

    3. Increases in strain within the plantar fascia will increase its tension which will, in turn, increase the tensile stress within the plantar fascia which will push the molecular structure of the fascia further up the stress-strain curve, closer to it's elastic limit, and which will lead to increased risk of plastic deformation of the fascia and plantar fascial injury (Wright DG, Rennels DC: A study of the elastic properties of plantar fascia. U.C. Berkeley Biomechanics Laboratory, Technical memorandum, October 1961; Whiting WC, Zernicke RF: Biomechanics of Musculoskeletal Injury. 2nd Edition. Human Kinetics, Champaign, IL, 2008).

    4. During running the tensile forces within the plantar fasica are probably increased due to the increased magnitudes of ground reaction force (GRF) acting on the plantar forefoot versus walking.

    With these known mechanical facts in mind, let's answer your questions:

    1)What mechanism is causing the stress?

    Answer: All weightbearing activities cause increased tensile stress within the plantar fascia. Some activities cause more increase in tensile stress within the plantar fascia than others. Large interindividual variation in plantar fascial structure may cause some individuals, more than other individuals, to have increased chance of having abnormal magnitudes of tissue stress in certain locations within the plantar fascia. Differences in plantar load-sharing forces between the tension-load-bearing elements of the plantar arch may also increase the tensile force within the plantar fascia which may, in turn, lead to increased risk of injury to the plantar fascia.

    2) Why do they have plantar fasciitis in the first place when they seem like unlike candidates who would not seem prone to such excessive stress in those tissues.

    Answer: Just because an individual has a "certain foot structure" does not necessarily cause the plantar fascia to not be subjected to large magnitudes of tension stress during all weightbearing activities, does not prevent running from causing significantly increased magnitudes of tension stress within the plantar fascia, does not prevent those individuals who have increased Achilles tendon tension from having increased tension stress in the plantar fascia, does not prevent weak plantar intrinsic muscles and excessively compliant plantar ligaments from increasing the tensile stress within the plantar fascia,and does not prevent that person from possessing a genetic or acquired variation within and along the length of the plantar fascial structure that would tend to cause a "stress riser" at some location within the plantar fascia that would, eventually, lead to plantar fascial injury. In other words, don't just consider "foot types" or "foot motion". Remember, rather, that variation in internal structure of a tension-load-bearing element of the foot, that Achilles tendon tensile force and that changes in load-sharing within the soft-tissue tension-bearing elements of the plantar longitudinal arch, in itself, may be a few of the critical factors which determine why the plantar fascia will develop the increased tensile stress within it that leads to plantar fascial injury.

    3) What design of orthosis can I use, I’m not sure about the mechanism and anything that supinates the foot will likely cause inversion sprains.

    Answer: Think not just about pronation and supination but also about decreasing Achilles tendon tensile forces within the sagittal plane. Think gastroc-soleus stretching, running and walking with shoes with increased heel height differential and night splints. Think about loading the lateral column with a reverse-Morton's extension to decrease the load on the medial fibers of the plantar fascia (Kogler GF, Veer FB, Solomonidis SE, Paul JP: The influence of medial and lateral placement of orthotic wedges on loading of the plantar aponeurosis. JBJS (Am), 81(10): 1403-1413, 1999). Think also about using a reverse Morton's extension to increase the subtalar joint pronation moment during the latter half of stance/support phases to prevent subtalar joint supination instability (Kirby KA: Foot and Lower Extremity Biomechanics: A Ten Year Collection of Precision Intricast Newsletters. Precision Intricast, Inc., Payson, Arizona, 1997). Think about using a plantar fascial accommodation in the orthosis so that excessive compression force from the orthosis is not being placed on the plantar aspect of the plantar fascia. Make certain that shoes with good heel height differentials with some arch support (i.e. no barefoot or flip flops) are used in all weightbearing activities to reduce the tensile stress within the plantar fascia during the whole day and not just when the patient is "exercising".

    Dave, with your engineering background, you will realize, more than most, that trying to predict the magnitude of internal loading forces and internal stresses within the supporting elements of a strucutre from having only a knowledge of the external shape of that structure, and without also possessing an intimate knowledge of the elastic modulus, thickness and three-dimensional variation in morphology of all the supporting elements of the structure and without having a knowledge of the tensile loading forces within the other supporting elements of that structure, is problematic, at best.

    In other words, we can't predict when injury will occur from "foot type" or "foot motion" unless we first know the internal loading forces and stresses at all points within the substance of the internal supporting elements of the foot and lower extremity. We are a very, very long way from having that knowledge.

    However, we do know, relatively well, how to reduce the pathological loading forces on the injured structural elements of the foot and lower extremity, even though we can't predict when these injuries will occur. It is for these reasons why Tissue Stress Theory should, and will ultimately become, the guiding theory for treatment of mechanically-based foot and lower extremity pathologies for many years to come.
  9. efuller

    efuller MVP

    A couple of questions:

    What do you mean by the MPJ is not low?

    Non weight bearing the foot is cavus. Weight bearing is there a normal or low arch height.

    There are some rare feet that have a normal to low arch height that will assume a quite high arch height. The first couple of these that I saw, I kept pushing up on the bottom of the first met head, when the patient was in the chair, and watching the forefoot plantar flex when I let go. The patients probably thought I was nuts. Anyway I've called these flexible cavus. I've heard others use the term and had no idea what they meant. I'm not sure that I'm describing the same thing they were. Anyway, my flexible cavus is one that non weight bearing has assumes a high arch position and with bearing the arch is much more normal and there is a big difference in arch height between weight bearing and non weight bearing. This seems to be what you are describing.

    Another finding common in these feet is thick, diffuse forefoot callus. The theory that I have to explain this is that during swing phase the foot assumes its high arch position and upon forefoot loading in gait, the arch has to flatten. This will necessitate sliding of the forefoot, hence the forefoot callus. This could also could cause high transient tension in the fascia as there is some momentum in the arch flattening that is stopped by the plantar fascia.

    A theoretical treatment for this is tight shoes. The shoe will push upward on the heel and forefoot and downward on the dorsal midfoot to keep the arch in its flatter position during swing phase. This is in addition to the usual orthotics.

    So, you have to explain the motions you see with moments. Most feet will pronate at the STJ when either the heel hits or very rapidly when the lateral forefoot hits in gait. Feet with laterally positioned STJ axes will pronate slower and some in stance will have active peroneal muscles. When they become inactive the foot will supinate. If it happens in stance it will probably happen in gait as well. This what I theorize to be cause of the midstance pronation that you seem to be describing above. In the feet you are describing, there is usually a contact phase rapid pronation that stops (or slows a lot) and then there there is an additional slower pronation between forefoot loading and heel off. Root and Weed called this late stance phase pronation or mid stance phase pronation (or something like that.) So, if the STJ motion stops, and then starts again, there has to be additional range of motion available. If there were no range of motion available it couldn't pronate any more. The feet that can "rest" at not maximally pronated are those feet with laterally positioned STJ axes. This is because they can get significant supination moment from the medial forefoot. In feet with medially positioned STJ axes, the medial forefoot is still on the pronation side of the STJ axis.

    Some people are able to keep constant tension in their peroneal muscles without painn.

    I'm not quite sure what you are describing on the pressure mat reading. I've had a few late stance phase pronators who showed quite a large shift from lateral to medial of the center of pressure between forefoot loading and heel off. I theorize that the medial forefoot load is what is causing the plantar fasciitis. The difference here is that pronation moment is from the muscle and not the ground. The plantar fascia will have increased tension with increased pronation moments. The plantar fascia won't know whether the pronation moment is from the ground or from muscles. (David W you described this accurately as to what I had said before.) So the theory of treatment is to reduce the high medial forefoot loads. Forefoot valgus wedge or reverse Morton's exttension. Sometimes a high medial arch of the orthoses, possibly with a plantar fascial groove.

    To repeat what I said above, there are two possible mechanisms. There is the flexible cavus foot that yanks the plantar fascia as the forefoot becomes loaded. And then there is the high medial forefoot loads from the late mid stance pronation. So tight shoes and increase lateral forefoot load.

  10. David Wedemeyer

    David Wedemeyer Well-Known Member

    Braggart! The misses must be pleased (sorry couldn't resist!)

    Never butting in Mike & always pleased at your input.

    Kevin and Eric :good:

    Dave some time ago and before I found PA I read this paper:


    It was of particular interest to me at the time and I thought answered some questions pertaining to my feet in particular. I still think its a good paper but I also feel that there are subcategories of this foot "type". PA and all of you have helped me to expand on the premise of the paper and look further.

    I'd love to hear your (and the others) feedback on this paper in this discussion. Although it doesn't describe the feet you are inquiring about specifically, I do feel that it is one variety of findings that we encounter and relevant to the discussion.
  11. David Smith

    David Smith Well-Known Member

    Thanks for all your thoughts

    David W - thanks for the paper there are some good points to think about in it.
    I would tend to make the type of orthosis they describe except that with a flexible, compliant midfoot I would tend to use a higher arched device but make it more flexible in the mid foot.

    As Kevin mentioned, a plantar fascia groove can accommodate a prominent PF but then there is the problem of increased orthosis stiffness in the mid foot. Perhaps I could use a lower arched device and add a soft pink poron 'D' pad on top.

    So I think I will go with a device with heel lifts, reverse mortons ext or perhaps lateral forefoot post and 1st MPJ c/o and lower the 1st ray area.

    What would you think about a small lateral heel skive to promote early pronation at heel strike instead of supination?

    Kevin, of course you are correct that there will always be a certain tensional stress in the PF with any weight bearing foot and things like tight achilles and equinus forefoot will tend to increase the stress and the designs you mention would be useful. Would you agree that this type of foot is more usually associated with peroneal, shock attenuation and lateral column problems than plantar fascia pathology? But there I am using foot type as a guide to pathology instead of focusing on tissue stress pathology and determining the biomechanism that would result in such stress. (and I don't even use foot typing, well not much anyway DoH!)

    So what is going on in terms of evaluating the kinematics and interpreting in terms of kinetics?

    The heel strikes and supination starts because the lateral STJ axis allows GRF to cause supination moments. The ankle dorsiflexes and the mid foot and valgus lateral forefoot strikes and so now the STJ is medial to the GRF and pronation occcurs. The foot pronates onto the 1st MPJ and the 1st ray is dorsiflexed as the heel starts to lift. GRF increases external dorsiflexion moments about the ankle and GRF sub 1st MPJ increases and the plantar CoP moves medially and this increases supination moments about the STJ and tensions the PF. And at the same time the ach ten is being tensioned which increases internal plantarflexion moments about the ankle and supination moments about the STJ and I see the foot supinate in propulsive phase.

    So it is probably around this early heel lift phase that is the time when the most stress in in the PF. So a strategy to reduce stress in the PF at around this time would be benificial and sounds lik ethe kind of prescription described above.

    Does this sound fair to you all?

    Mike what was the bit about no rearfoot device? did you mean no rearfoot posting or heel lift and by cuboid notch did you mean cuboid pad or a cut out? If cut out then what does this achieve?


    You wrote
    The 1st MPJ is on the same plane as the lesser MPJs and is not plantarflexed relative to them, of course with a valgus forefoot the 1st MPJ will be lower than the lesser MPJs relative to a ground reference frame.

    Yes non weight bearing the feet are cavus (but the mid foot is flexible and compliant) Weight bearing the medial arch lowers to about 'normal' i.e. visual evaluation does not indicate excessive lowering and therefore extension strain of the PF (one would imagine anyway but as Kevin notes it is impossible to tell the strain in a tissue by visual evaluation of motion.) So (good thought Eric) there may be the same amount of PF extension as on a normal arched foot that becomes low arched on weight bearing.

    This is all good stuff to work the cobwebs out of my stuffy thinking.:dizzy:

    Dave Smith
  12. Hi Dave

    - No rearfoot post

    The plantar fascia has increased tension just pre and post midstance , I believe in my feet ( similar to the feet you describe) the post midstance is where increase the plantar fascia tension becomes problematic, so would focus on this part of gait and therefore would not use a lateral skive.

    A cuboid notch - lift under the cuboid

    sorry for the short message, I have more but have to go a 16 month old is demanding some attention. :D
  13. Dave:

    If the patient is truly undergoing subtalar joint (STJ) supination motion during contact phase, then I would add a 2-3 mm lateral heel skive to the orthosis and possibly consider making the rearfoot post flat, with no motion.

    You can use the forefoot valgus wedge/reverse Morton's extension to effectively reduce the plantar fascial tensile force within the most medial fibers of the plantar fascia. In addition the forefoot valgus wedge/reverse Morton's extension will effectively reduce the external STJ supination moments and/or increase the external STJ pronation moments during the latter half of stance phase.

    A properly made plantar fascial accommodation with the orthosis plate medial to the medial band of the plantar fascia made with good arch contour can be quite effective at reducing the load on the medial band of the plantar fascia. In order to further decrease the medial midfoot/medial column loads in these feet, I will increase the plantar loads on the lateral midfoot by adding a plantar filler in the lateral longitudinal arch in order to stiffen the lateral longitudinal arch of the orthosis.

    Typically, patients with laterally deviated STJ axes, even though they are much less common than patients with medially deviated STJ axes, will have characteristic kinematic findings during gait. Generally individuals with laterally deviated STJ axes will supinate slightly at heel contact, stay relatively supinated in early stance phase, undergo STJ pronation motion in late midstance and then supinate again after heel off. These patients will also typically have a relatively short propulsive period, have little active ankle plantarflexion during propulsion and will have relatively short stride lengths.

    The time in gait where the plantar fascial tensile stresses are the greatest in these patients are during the late midstance phase when the ankle is dorsiflexing and the STJ is pronating, instead of the STJ supination motion that should normally be seen during late midstance.

    The most likely cause for the late midstance pronation in these feet is that the central nervous system (CNS) senses that with the center of pressure (CoP) so medial on the plantar forefoot during late midstance, STJ supination instability, and possibly a lateral ankle sprain, would likely occur during propulsion if the CNS fully activated the gastrocnemius-soleus muscles during propulsion. Full activation of the gastrocnemius-soleus muscles by the CNS during propulsion would greatly increase the internal STJ supination moment during propulsion [since the Achilles tendon is quite medial to the STJ axis in these feet]. Therefore, the CNS "decides" rather to activate the peroneals more fully to increase the internal STJ pronation moment during late midstance. which causes the late midstance pronation motion in late midstance. The CNS also "decides" to decrease the magnitude and duration of efferent activity to the gastrocnemius-soleus muscles during late midstance and propulsion to avoid excessive STJ supination moments that could cause a lateral ankle sprain.

    Adding the lateral arch filler to stiffen the lateral longitudinal arch of the orthosis along with the valgus forefoot extension/reverse Morton's extension under the metatarsal heads will shift the CoP on the plantar forefoot to a more lateral locaton during late midstance and propulsion which will, in turn, increase the external STJ pronation moment during late midstance and propulsion. Now, with the CoP more lateral on the plantar forefoot during late midstance and propulsion, the CNS "senses" that it can now normalize its neuromuscular efferent activation pattern that it could not do without these CoP lateralizing modifications by doing the following:

    1. The CNS may now reduce the magnitude and duration of efferent activity to the peroneal muscles during late midstance and propulsion since it "senses" that the external supination moments will not be excessive during late midstance and propulsion. The kinematic result of this event is either less late midstance pronation or more late midstance supination.

    2. The CNS also "senses" that it can fully activate the gastrocnemius-soleus muscles during late midstance and propulsion since the additional external STJ pronation moment from the valgus wedged forefoot extension/reverse Morton's extension will now be able to effectively counterbalance the additional internal STJ moments that will come from full activation of the gastrocnemius and soleus muscles during late midstance and propulsion. The kinematic result of this event will be more active ankle plantarflexion during propulsion, a longer propulsive period, and a longer stride length.

    The kinetic result of CNS events #1 and #2 will be reduced loads on the medial band of the plantar fascia during late midstance and early propulsion and, hopefully, less symptoms for the few patients that have this unique foot type and symptom complex.

    Hope this helps explain these concepts more fully.:drinks
  14. efuller

    efuller MVP

    I'd have no problem putting a lateral heel skive in a foot with a laterally positioned STJ axis. In addition to the reverse morton's or forefoot valgus extension you can have the cast made with an intrinsic forefoot valgus post.

    There are many ways to type a foot. STJ axis position is one of them. Laterally deviated STJ axis foot will tend to have the problems you mention more than medially deviated STJ axis feet. (I'm not so sure about shock attenuation though.)

    When casting the feet with a large difference between non weight bearing arch height and weight bearing arch height I will sometimes dorsiflex the forefoot. If you don't do this when casting, you could get an orthotic with a very high medial arch. (Is this why you wanted a more flexible orthotic?) When you dorsifex the forefoot when casting, you are more likely to get a comfortable arch height and the orthotic can be made more rigid. So, then you can add the plantar fascial groove, if it is prominent.

    Arch height is one factor in planar fascial tension. Pronation moment and load on the first met head are also factors. So, it is possible to get high loads in the medial slip of the fascia with a average arch height foot.

  15. David - in your mothers tone. :D

    Hi Dave at work now so not 16 month old getting in the way just a research paper and orthotics this morning,

    As I said before the tensile force in the plantar fascia increases pre and post midstance, so if we look at when the patients is having plantar fascia tension related issues, if like me then it will be the post midstance phase of the gait cycle, this is where I would concentrate on looking at where a device can be implemented to reduce tensile forces acting on the plantar fascia at this time.

    This is key for me - and at this point we need to look at Where CoP is and where it is travelling. Again I would not worry about a lateral skive and will ask/discuss with Eric below about my negative thoughts when using it in this type of patient - probably be wrong ;), but then you indirectly taught me something :drinks which is what it all about,

    Eric if we use a lateral skive will we not be reducing the tension in the peroneus longus are we not reducing the postive effect of the tendon on the windlass mechanism, also will not the lateral skive add in acceleration of STJ pronation, as Dave has said the foot is in a more pronated position at midstance - lateral deviated to `normal `so a kinematic pronation change, if we use a lateral skive will not there be acceleration and therefore ( F= m*A ) we have increased the force of the pronation moment which will then lead to greater tensile loads on the plantar fascia post midstance ?

    Better go
  16. David Smith

    David Smith Well-Known Member

    Ok Guy great stuff thanks,

    There seems to be a general consensus that heel lifts, PF groove and rev mortons or valgus f/f post and ankle mobs plus stretching and RoM exercises are the prescription features in this case. There seems to be some disagreement about arch height and flexibility, lateral rearfoot skive and cuboid pad. I think I'm going with Kevins argument on those and also see how a cuboid pad works with each patient. I think the cuboid pad stabikises the lateral column when there is a lot of deformation in the lateral arch.

    I would have thought that lifting the cuboid with a pad and therefore raising the lateral arch would release tension in the peroneus longus. My idea of using a cuboid pad is more to do with stopping the cuboid rotating in the frontal plane and the 'beak' dropping down and disengaging the cuboid from the nav and so increasing midfoot compliance.

  17. Reducing the tension from the cuboid to the origin, but increasing the tension from the insertion to the cuboid - maybe, but as Eric points out there may only be a change in tension as I described if the muscle in already under load, which I would say it is with foot you describe.

    There will be other effects of the pad of course. But any way you can resist the Dorsiflexion moments on the metatarsals and this maybe 1 (?)
  18. efuller

    efuller MVP

    The problem, in the feet we have been discussing, is that the peroneal tension is too high. We want it to shift toward an average amount of tension. So, with a lateral STJ axis, both peroneus longus and brevis will be more active. Their activity will pronate the STJ and load the medial forefoot as the forefoot loads. This is what I'm theorizing will cause plantar fascial symptoms in someone with a lateral STJ axis. A very interesting research question is will a valgus wedge (heel and or forefoot) reduce both longus and brevis firing. So, it is theoretically possible to maintain peroneus longus activity, while decreasing peroneus brevis activity. For me, the treatment in this case is shifting weight off of the medial forefoot.

    Yes, a lateral wedge will increase pronation moment from the ground. However, a pronation moment from the ground will lead to a decrease need for pronation moment from a muscle. The peroneal activity is high in feet with laterally positioned STJ axis feet, because there is low pronation moment from the ground and the Achilles tendon tension will tend to add supination moment as the forefoot is loaded. So, the peroneals have relatively high activation to prevent an ankle sprain. You have to think in terms of net pronation moment. If you lower the supination moment from the ground, you don't need as much counteracting pronation moment from the muscles. I believe the body can adapt to this change quickly. When I was experimenting with my own orthotics, I was able to add enough varus wedge that I could feel my peroneal muscles start working more, especially at heel contact. My example is in the opposite direction of the discussion, but the concept still applies.

    Hope this helps.
  19. efuller

    efuller MVP

    Cuboid pads:

    I beleive that a cuboid pad will increase force under the cuboid and tend to shift the center of pressure laterally.

    I don't think that they can raise the lateral arch. You can shift the load proximally with the pad. That proximal shift may not necessarily raise the arch. The anterior portion of the arch will have to "fall" to the ground and it cannot accept much load if it has fallen to the ground. Once the heel lifts off of the ground, you've lost all of your potential arch raise.

    I don't understand how a cuboid pad will stop the cuboid from rotating. The pad will push the cuboid upward, but I don's see how that makes it rotate.

    Dave, I don't understand what you mean by the cuboid disengaging from the navicular. They are bound together by ligaments and there is a slight amount of rotation between the two, but I question as to whether this rotation is clinically important.

  20. efuller

    efuller MVP

    The paper does identify some characteristics of the laterally deviated STJ axis foot. It is good in that regard. However, that diagram of peroneus longus and equinus was quite bad. They just threw some arrows on a drawing without looking at the actual path of tendons.

    Their concept of peroneal overdrive was a good observation with a bad explanation. You will see the foot with the plantarflexed first ray. Their drawing is trying to blame this on change of pull of tendons and the equinus. I feel that a better explanation is the function of peroneus longus changes in a laterally deviated STJ axis foot as opposed to an average axis foot. The peronus longus simultaneously creates an eversion moment from the upward pull on the cuboid and a first ray plantar flexion moment. (The plantar flexion moment comes from a force couple of the rearward pull of the tendon and compression forces at the metatarsal cuneiform joint and not the downward pull of the tendon as depicted in their drawing.)

    The plantar flexion moment on the first ray and the pronation moment create competing moments at the STJ. Plantar flexion of the first ray will tend to shift the center of pressure more medially. In a foot with a lateral stj axis this medial shift of the center of pressure will create a supination moment from the ground. This supination moment from the ground is competing with the direct upward pull of the peroneus longus muscle on the cuboid. The bigger one wins. In a laterally deviated STJ axis foot the peroneal muscles may have a smaller lever arm when compared to an average axis foot. So, the muscle will create a smaller pronation moment than in the average foot. Thus the phenomenon that the paper describes as peroneal overdrive can be explained by STJ axis position.

    The paper also describe an orthotic. It wasn't quite clear, but it seemed that the orthotic they were recommending had a forefoot valgus wedge or was at least the same as a reverse Morton's extension. Either of those modifications will shift the center of pressure laterally which is beneficial for a laterally positioned STJ axis foot.

  21. David Smith

    David Smith Well-Known Member


    There is much in the literature about how the Cuboid subluxes and how to manip it back into place using cuboid whip technique or similar (something I have used many times with great and immediate success) and, as I understand, the subluxation is described as a frontal plane valgus rotation and a plantar translation where the result is that the beak of the cuboid protrudes plantarly. Often this is associated with tension in the PL tendon. This would indicate that there is the possibility of a significant displacement of the cuboid in some feet.


    I imagine you must have read this literature, which makes me wonder why, it appears at least, you do not agree with it?

    Regards Dave
  22. RobinP

    RobinP Well-Known Member

    Thanks for this Eric. I have been thinking my way around this for some time now and this very concisely states what is happening in my minds eye.
  23. Yeah, as I've said many times before- I'm still waiting to see an image pre and post manipulation..... Show me the change in bony position.
  24. efuller

    efuller MVP

    I've done a few manipulations myself. When it works it makes you, the practioner, feel real good. However, my rationale for doing it is that it has worked in the past. I'm not terribly happy about the subluxation and or rotational explanations. I read something once that I liked more and that is there is a labrum, kind of like the meniscus of the knee, in the CC joint. My theory is that this structure is altered by the manipulation. If someone comes up with a better explanation, I'd drop that one pretty quickly.

    Another picture with arrows drawn on it without regards for all of the forces present. The tendon slides quite easily in the notch in the cuboid. For that diagram to work, there would have to be friction between the tendon and cuboid. Doing a free body diagram of the tendon there is tension upward and rearward from the muscle belly. At the same time there is tension on the tendon forward and from lateral to medial from the base of the metatarsal. To acheive equilibrium on the tendon the cuboid must push from dorsal medial to plantar lateral. Therefore there must be an equal and opposite force from the tendon applied to the cuboid that is from plantar lateral to dorsal medial in the frontal plane. It's hard to see how this force could cause a cuboid rotation in the frontal plane. I've examined the CC joint in cadavers, and I can't imagine how the beak of the cuboid would point plantarly without some serious disruption of the plantar ligaments.

  25. Here is what I said on August 13, 2011 regarding cuboid syndrome:


    I agree with Simon and Eric, if the cuboid is "subluxed", then why can we image it before and after manipulation to see evidence that it was "subluxed"? I vote for the labral theory, until proven otherwise.
  26. David Smith

    David Smith Well-Known Member

    Kevin, Eric, Simon.

    You are consistent Kevin, in April 2006 you wrote

    Craig Payne did appear to be more considerate of the possibility though

    I take note of your caution and scepticism and it is well discussed in the thread noted above. However, I am sure that I have had patients where the cuboid is planatarly and palpably prominent. They have symptoms associated with cuboid syndrome and after manipulating the cuboid back so it is no longer palpable and also making an insole with a cuboid pad, then their symptoms resolve. That is consistent with much literature and seems to be enough clinical proof for me. Ideally I would follow up with research resulting in tangible evidence.

    It's all good food for rational thought though e.g. Is it valid and/or useful to keep doing something that appears to give the outcomes required and predicted if that procedure cannot be backed up with tangible evidence to indicate what you are doing is what you think you are doing.

    Regards Dave
  27. timharmey

    timharmey Active Member

    Sorry to but in on a debate by the great and the good,I have been interested in this subject for a while.I am going to look into it in a scientific way , even if my research skills are not all that. My thoughts are for what they are worth , is that by performing a cuboid mob , the effect is caused by a neurophsiological effect on peroneous longus.I have not researched this but will and have applied to convert the few masters modules I have to undertake a Msc to that that end.
  28. We did a quasi experiment ith emg activity of peroneus longish pre and post manipulation of the fibula at the conference in Florida last October- funny results. On retest the emg signal was altered on both sides even though only one leg had been manipulated- remember that Kevin?
  29. timharmey

    timharmey Active Member

    A physio friend of mine thinks these findings at least in part may be explained by gait literature and central pattern generators
  30. David Wedemeyer

    David Wedemeyer Well-Known Member

    So much to say and so little time, I will be back with some comments re the paper and the subluxed cuboid discussion :D
  31. David Smith

    David Smith Well-Known Member

  32. markjohconley

    markjohconley Well-Known Member

    I have just attended to a 50 y/o female, with a history of "frequent" lateral ankle sprains of both feet. The incidents occurred mostly when walking over "uneven ground".
    On examination whilst the patient was in static stance, bilaterally the peronei tendon seemed to be under considerable load. Only moderate force was needed to invert the foot with the supinaton resistance test. On moving the sub-talar joints (STJ) through their range of motion (ROM) passively it was noticed that there was increased frontal plane component and decreased sagittal plane component (relative to other patientsi've tested). The patient has thick callus plantar to both 2nd and 5th metatarsophalangeal joints (MPJ).
    From this, I have diagnosed? a laterally deviated STJ axis (Transverse Plane) resulting in increased internal pronatory moments about the STJ axis from the peronei, resulting in a STJ functioning towards the pronated end of its ROM, resulting in decreased 1st ray plantarflexory moments during late mid-stance and propulsive phases, resulting in a reduced ground reaction force (GRF) plantar to the 1st MPJ, resulting in increased GRF plantar the the 2nd MPJ, resulting in formation of the plantar 2nd MPJ lesion, HOWEVER i can't explain the plantar 5th MPJ callus, anyone?? thanks, mark
  33. In a foot with a laterally deviated subtalar joint (STJ) axis, ground reaction force (GRF) will cause a net increase in external STJ supination moment. As a result, the STJ will tend to undergo supination motion unless resisted by an internal STJ pronation moment and/or an external STJ pronation moment.

    In your patient, Mark, the peroneal muscles are causing the internal STJ pronation moment and GRF plantar to the 5th metatarsal head is causing the external STJ pronation moment. In other words, both the peroneal muscles and GRF acting on the plantar forefoot lateral to the STJ axis help to counterbalance the excessive STJ supination moments from the laterally deviated STJ axis so the foot won't maximally supinate at the STJ during relaxed bipedal stance and during gait.

    Hope this helps.
  34. markjohconley

    markjohconley Well-Known Member

    Thanks Kevin, typical clear, informative reply. I'll inform the patient next appointment with an added, "It was Prof Kirby".
    Depending on the magnitude of the STJ supinatory moments the peronei alone would not be enough to "counter" with an opposite moment of equivalent magnitude??
  35. Mark:

    A better way of putting it would be to say that if the patient had a 5th metatarsal head resection surgery, the peroneals would need to have even more contractile activity to make up for the external STJ pronation moment that previously had come from the GRF acting plantar to the fifth metatarsal head before the 5th metatarsal head resection surgery.

    These feet commonly have hyperkeratotic lesions plantar to the styloid proces of the 5th metatarsal and 5th metatarsal head which are caused by the excessive STJ supination moments from the laterally deviated STJ axis inverting the forefoot harder into the ground. In the photo shown below, the STJ axis is more laterally deviated on the left foot than the right foot and the callouses on patient's left foot plantar to the 5th metatarsal head and styloid process of the 5th metatarsal are worse than those present on the right foot.

    Or, in other words, the resistance of the 5th metatarsal to dorsiflexion loads (i.e. dorsiflexion stiffness) in response to GRF helps to create additional external STJ pronation moments that, in turn, reduce the tension force within the peroneal tendons which, in themselves, create an internal STJ pronation moment.
  36. efuller

    efuller MVP

    I'm going to say what Kevin said a little differently. In feet with laterally positioned STJ axes the center of pressure can sit directly beneath the axis, thus causing no moment from ground reaction force. The center of pressure is the point of no net moment from the ground. In otherwords, the force x distance from one side of the center of pressure is equal to the force times distance from the other side of the location of the center of pressure. (This is when no muscle activity is occuring). So, if the axis is very far lateral, then amount of foot on the lateral side of the axis will be small, and the distance to the axis will be relatively small. Since the distances are smaller on the lateral side of the axis, the forces will have to be higher to create the same amount of moment to achieve equilibrium. So, when the patient "rests" their peroneal muscles there will be higher forces under the fifth met.

  37. markjohconley

    markjohconley Well-Known Member

    I thought the different spatial location of the STJ axis, the transverse plane component, was mainly related to a rotation rather than a translation.
    In the photo Kevin attached to his post, is that axis a laterally (translated) deviated STJ axis?
    Whether translated and / or rotated i understand there would still be a greater external supinatory moment from GRF (and possibly a greater internal supinatory moment depending on relative muscle attachment position), Mark
  38. efuller

    efuller MVP

    I remember talking with Kevin soon after he published the palpation of the axis paper. He said that he wished that he had not used the word deviated as it implied a rotational (e.g. STJ axis moving relative a transverse plane point for example, the center of the tibia) He mentioned that he noted that sometimes the axis appears medially or laterally shifted. I agree with this observation.

  39. markjohconley

    markjohconley Well-Known Member

    Thanks Eric. As I have difficulty performing the TP STJ axis location, I have been moving the rearfoot through its STJ ROM and, because I assumed the deviation was rotational, have tried to assess the relationship of frontal plane to sagittal plane component motion to determine the 'deviation', Mark.
  40. markjohconley

    markjohconley Well-Known Member

    Goodaye Eric, I'm reading this as "is it", is that right?, thanks, mark

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