Welcome to the Podiatry Arena forums

You are currently viewing our podiatry forum as a guest which gives you limited access to view all podiatry discussions and access our other features. By joining our free global community of Podiatrists and other interested foot health care professionals you will have access to post podiatry topics (answer and ask questions), communicate privately with other members, upload content, view attachments, receive a weekly email update of new discussions, access other special features. Registered users do not get displayed the advertisements in posted messages. Registration is fast, simple and absolutely free so please, join our global Podiatry community today!

Foot orthoses outcomes and kinematic changes

Discussion in 'Biomechanics, Sports and Foot orthoses' started by Craig Payne, Dec 11, 2004.

  1. Craig Payne

    Craig Payne Moderator


    Members do not see these Ads. Sign Up.
    1. We all use various types of foot orthoses in clinical practice in an attempt to alter the pattern of rearfoot motion to "improve" biomechanics and make patients better.
    2. Numerous outcomes studies, patient satisfaction surveys (many with methodological flaws) and RCT's show patient do get better with foot orthoses that attempt to alter the pattern of rearfoot motion.
    3. The numerous kinematic studies (many with methodological flaws) are about evenly divided as to if foot orthoses do actually alter the pattern of rearfoot motion or not. Half show no differences in rearfoot kinematics and the other half show such small (but statistically significant) differences that the biological significance of those differences need to be questioned.

    Does anyone see the paradox here? :confused: What we do clinically works, but not by trying to do what we think we are doing :confused: (... as I tell the students - I used to know what I was doing)

    In an attempt to resolve this paradox, one of our projects this year measured patient symptoms (FHSQ) at issue of foot orthoses and at 4 weeks follow up. At issue of foot orthoses, rearfoot kinematics was also measured with and without the use of the foot orthoses. Guess what we found? ---- there was no correlation between changes in the pattern of rearfoot motion and symptom reduction :confused:

    This is troubling as I have spent most of my professional life trying to alter patient's pattern of rearfoot motion .... they get better, but not because of the changes in rearfoot motion :rolleyes:

    What say you?
     
    Last edited by a moderator: Dec 11, 2004
  2. Ian Linane

    Ian Linane Well-Known Member

    Hi Craig

    Forgive naive in put but does the following perhaps contribute to the debate.

    1. Ultimately, the human body / mind knows what it needs to maintain
    stability in motion and any attempt to bring physiological forces that
    enable it to move towards what it needs are readily seized by the body /
    mind. This is a holistic approach that I supect we greatly undervalue in
    our reductionist methods of medicine.

    2. The applied forces to the rear foot succeed (if that is the word) not so
    much by changing the pattern of rear foot action but by the aquired
    changes in the mid and forefoot resulting from change in rear foot position.

    3. Rear foot action is very much about intial contact and I wonder if it is a
    point when mechano receptors in the muscles are least active overall
    (someone who knows this stuff can happyily correct me).

    4. Perhaps, the altered midfoot position at ground contact feed
    long lost proproceptive information through hitherto limited (due to lack
    of stimulation via overpronation) feed back mechanoreceptors and, even
    milliseconds prior to early heel lift, the forefoot signals are responded
    to more quickly. (Within the little bit of treatment I do for mind issues we
    speak of an atavistic state, a throw back to primitive processes.
    Perhaps the change in rearfoot, its consequences upon mid and forefoot
    mechanoreceptors begins to generate a healthy throw back into mind
    memory of how our limbs should be working.

    5. Where the full effectiveness of this may fall down is at the point in heel
    lift where the mid foot is most vulnerable to MTJ in roll because it does
    not have an undulating surface to walk on.
    (Do the cases where rear foot control seemed less effective reveal if the
    midfoot inrolled on these people more?)

    Just some ideas. They may be crap but hopefully I can at least write reasonable crap if not good biomechanics. :D

    cheers
    Ian

    Ps. Craig, did you get email regarding your university having image resources
    of body posture
     
  3. Craig Payne

    Craig Payne Moderator

    I am not so sure its proprioception/sensory input - we have now done several post tib nerve block studies and ice studies (to numb plantar surface) and studies using 40grit sandpaper on top of orthoses (to increase sensory input) - in all studies alterations in sensory conditions/input did not alter the kinematic response to the foot orthoses ...... several studies by others have shown the importance of plantar sensation to balance and stability, which we are not investigating. We were concerned about, do you have to feel a foot orthoses (ie sensory input) to respond kinematically to it? - the answer so far is NO.

    At the end of the day, we use foot orthoses to alter foot function to get symptomatic relief. We have measured a whole battery of kinematic, kinetic, EMG and pressure parameters/variables in several studies to see what ones foot orthoses do actually alter and MOST IMPORTANTLY, which of the parameters/variables are related to a reduction in patient symptoms (plantar fasciitis and patellofemoral pain sydrome are the two populations we are using) - the main study (above) showed it wasn't reafoot motion changes that are related. We think we have narrowed it done to just one functional parameter (or maybe 3) that foot orthoses do alter that is related to symptomatic relief. We just not yet ready to 'sing and dance' about it yet until we finish 2 RCT's next year testing it and look at the validity/reliability of clinical tests associated with it.... watch this space :eek:
     
  4. Ian Linane

    Ian Linane Well-Known Member

    I'll keep watching! :cool:

    As you feel to have a inkling already do you think my suggestions are way of beam?

    Ian
     
  5. davidh

    davidh Podiatry Arena Veteran

    Hi chaps,
    Rearfoot control to control the rest of the foot was how I was taught biomech many moons ago. I was taught (like many others) that a rearfoot post tilted the calcaneus (in some way) and this influenced the position of the foot in midstance and therefore toeoff.

    However, after working with a vertical loading gait analysis system for a few years (Musgrave) I began to realise that the vast majority of my patients simply didn't load anywhere near full bodyweight until they had finished heelstrike and were in the first half of midstance.
    Was the load at heelstrike enough to "tilt" the calcaneus?
    What seemed much more likely to me was that the medial heel correction was simply acting as a stabiliser for the expensive "arch supports" I was fitting :eek: .
    I still subscribe to this.
    Regards,
    David
     
  6. Craig Payne

    Craig Payne Moderator

    I have been doing that for years and teaching it for years ---- IT WORKS -> patients actually get better when doing it (the evidence shows that they get better). But the evidence is also clear, that when we try to do it, it dosen't actually happen, but the patient still gets better .... don't figure :confused: .... remind me in 6 months to come back to this thread with what I hope is the answer with the evidence.
     
  7. davidh

    davidh Podiatry Arena Veteran

    Here I go with a "conjecture-vs-science" comment :) .
    I found my patients got better too, but I suspect not for the reasons I was taught.

    Nowadays, by using mostly small (2 degree) FF posting only for the majority of my patients they still get better. I notice that they respond as fast but with not so much of the acclimatising problems I used to have with 4-degree rearfoot posts. Devices can be smaller too :) .
    I still use heel-lifts as needed.

    As an aside to that, in conjunction with a colleague and a well-known USA lab, this summer we developed a casted device which can be used in a soccer boot. Professional players in the UK (and guys from outside the UK but who play for UK clubs) pretty much all wear their boots anywhere from one to three sizes too small. Hence there's a problem getting a rearfoot-posted device into the boot along with the foot. The FF-posted soccer orthoses are currently used by some of the players from two Premiership Division clubs - they're comfortable straight away, the player can still wear his boots too small, and they seem to be working :D !

    Look forward to your research findings Craig.
    Cheers,
    David
     
  8. pgcarter

    pgcarter Well-Known Member

    I would venture to suggest that it is not always rear foot motion patterns that are indicative of symptoms anyway....this was Roots idea though. I like the idea put forward by the English guys about forefoot controlling rear foot through muscular responses to pressure changes under foot. Not sure I'm really saying it the way they did....but I think in practice I'm much more concerned with forefoot/first met shaft position and timing/success of hallux dorsiflexion than I am with rear foot position.
    I think I see many feet that have trouble that hardly move in the frontal plane at all but are excessive pronators at STJ....I don't try to change the rear foot motion....I try to change first ray function.....which is really about the forefoot and its relationship to the ground.....which of course has a BACKWARD REACHING? influence on the rear foot.
    How's that for holistic groping in the dark?
    Regards Phill
     
  9. Ian Linane

    Ian Linane Well-Known Member

    I knew Australian Podiatry courses were more interesting than English ones. "Groping in the dark" never appeared on our curriculum. :(
    If I stay posting on this site long enough can I do an MSc in it? :D

    Ian
     
  10. Sean Millar

    Sean Millar Active Member

    rearfoot position

    In my limited clinical experinece rearfoot position influences 1st ray function. This is particularly apparent in Functional hallux limitus. the 1st phalanx has limited dorsiflexion on the 1st met. in rcsp, however this usually improves significantly in ncsp. Which lends support to the arguement that the reafoot position, may be influencing structures more distally. Following on from this, I usually find when the client stands on a functional orthotic, the 1st phalanx dorsiflexion is greater than when the orthotic is not in place. The large assumption is the relates to dynamic gait :confused:
     
  11. Craig Payne

    Craig Payne Moderator

    There are two publications that support this - BUT, we pretty sure its not really changes in rearfoot position/motion that influences the first ray motion. We pretty sure it changes in the rearfoot kinetics (ie forces) that influence first ray function. We can easily get changes in first ray function by influencing rearfoot forces without actually changing rearfoot position or motion (kinematics). Its just when you do manage to change rearfoot position, you also change the forces. BUT, you can change the forces without changing the position..... here in lies the answer (and don't forget its kinetics (ie forces) that damage the tissues and not motion or position (ie kinematics). Symptoms get reduced only when the forces in the tissues are reduced.
     
  12. Sean Millar

    Sean Millar Active Member

    rearfoot position

    The last australiasian conference started to bring these issues the arena. but from a practical issues. how do we measure the kinematics in a clinical situation?. is it something we could include in our daily practice? the possibility of being able measure our infleunece on the foot more quantatatively is very exciting. :cool:
     
  13. Craig Payne

    Craig Payne Moderator

    I don't want to say too much until we are more sure we are right. But we testing validity and reliability of a couple of static clinical tests with and without patient standing on foot orthoses to predict the kinetic changes dynamically ....watch this space.
     
  14. pgcarter

    pgcarter Well-Known Member

    Iain,
    In view of current work place political correctness, I can assure you the lights are always on....and there is no groping...as interesting as it sounds, but I regularly urge my students to cop a feel of as many feet as they can get their hands on....all good experience for clinical practice.
    On a more serious note I do have trouble in early second year getting them to actually touch each other (on the feet) in my classes to begin to get a good broad base line "feel" for feet.
    Regards Phill Carter
     
  15. Robert D. Phillips DPM

    Robert D. Phillips DPM Welcome New Poster

    orthotic function

    Hello Craig,

    I enjoyed your comments about orthotics not highly affecting the kinematics, yet providing invaluable aid of symptoms. :eek:

    Just a few comments to back you up in your observations, yet I'm sure you've discussed these possibilities with your students many times.

    1) Interestingly, Root maintained that you only have to control the last 1 degree of pronation (or maybe less) to have complete resolution of symptoms. He maintained that pronated feet are not usually symptomatic, only subluxed feet. So you need very little change in kinematics to feel marked relief of symptoms

    2) I think Irene McClay did a nice job with the Blake orthotic study to show that it was the kinetics, not the kinematics that was so drastically changed.

    3) I believe that many of the changes are not in the rearfoot to ground, but in the forefoot to ground and the forefoot to rearfoot kinematics, especially in the intercuneiform relationships. Haven't figured out the best way to measure these.

    4) Most of the studies do not utilize each subject as their own control, but instead give averages for a large variety of foot types. For example, it would be interesting to see what happens only in those type of feet that are judged to have 5-10 degrees of forefoot varus with all other parameters nearly normal. Good luck trying to find such a population that is large enough to study.

    So with those small observations, it would be interesting to try to understand the real reasons for so many of treatment modalities working, but the problem is that no one wants to develop their education background necessary to understand the real reasons.

    With a politically correct happy holidays to everyone. best wishes for the new year, :)
    Daryl Phillips
     
  16. Ian Linane

    Ian Linane Well-Known Member

    Sensory Feedback

    "We were concerned about, do you have to feel a foot orthoses (ie sensory input) to respond kinematically to it? - the answer so far is NO."


    Hi Craig.

    Something I wanted to note a while ago in response to the above. Where we feel orthoses is significant and I wonder if the assessment of the numbed lower limb took into account the downward feed of information:

    A person may not feel the affect of the orthosis in the numbed foot / leg but the change in centre of gravity in gait and position of other aspects of the body may be feeding the body / mind scenario. Surely feed back is not simply oneway. A minor change in position of the trunk (resulting from the unfelt-foot- but mechanical reality of changed position) would, I am assuming, cause muscular reaction in a downward direction.
    Would this be sufficient?

    Cheers
    Ian
     
  17. Craig Payne

    Craig Payne Moderator

    Not sure - we just starting to get into this. We are looking at doing some work on "leg stiffness" (the biomechaical defnition of stifness) and the influence of that at heel contact on the parameters that we want foot orthoses to influence - ie the influence of these proximal factors, of which this is just one.
     
  18. Craig Payne

    Craig Payne Moderator

    Daryl
    Good to hear from you.
    [​IMG]
    I know this off-topic, but I have been watching Fox News lately (...yes I know its more to the right), but I can't get over some of what I am seeng:
    * baning of nativity scenes by some government agencies
    * christmas not being celebrated by some schools
    * all the litigation surrounding the political correctness of christmas
    * a teacher allegedly suspended for talking about god in the context of the declaration of independance...

    Talk about political correctness gone nuts![​IMG]

    I do enjoy the Bill "no spin zone" O'Rielly show - mainly cause he drives liberals nuts! and I love the way they go back at him :eek: - but, did you read this critics attack on O'Reilly's stand on Christmas Under Seige ?

    Also, this from WorldNetDaily:
    God bless the USA :)
     
    Last edited by a moderator: Dec 28, 2004
  19. Ian Linane

    Ian Linane Well-Known Member

    Thanks for the reply Craig. Found the Fox articles and responses fascinating.

    I was in disussion with a physio colleage of mine who, like me, also is involved in holist approaches to treatments. We discussed proprioceptive responses and he reminded me of the holistic principle of "less equals more"
    i.e. a little lets the body do a lot but that the more we do the less the
    body can do.

    I paste below his comment:

    "One thing that comes up over and over again in Holistic Medicine is "Less = More!".

    I am very ill equipped to argue biomechanics with you or any of the very esteemed contributors to this debate but I suggest that the tests for proprioception were too 'heavy handed'.
    Remember the fable of the Princess and the Pea?

    Where zero interference = maximum allowance for holistic accommodation to external forces and 100% interference = total opposition reflex then, I suggest that the nearer one gets to zero stimulation, the greater the automatic proprioceptive adjustment.

    (e.g. I have just discharged a patient who presented with G.minimus spasm. He failed to respond well to either ultrasound or interferential therapy and was unable to tolerate deep petrissage. Bea reminded me of the "Less = More" philosophy and as a last resort (and with a great deal of trepidation) I 'tickled his bottom'. The result after 10 mins? Instant relaxation of the muscle which has been sustained with reducing applications of heat over a few days at home.)

    Worth a thought?"


    Taking into account the previous post where Root was suggested to say that it is the last degre of pronation that was significant

    People generally adapt well to significant callous etc but a simple, tiny stone in the shoe generates remarkle alteration of gait. :eek:

    Cheers
    Ian
     
  20. Glenn Z

    Glenn Z Welcome New Poster

    G'day Craig
    Something that does not seem to have been raised is that the device modifies the timing of motion/loading in pedal joints. Given the complexity of foot function, a small alteration in the timing of the application of a force, irrespective of its magnitude, has the potetnial to allow the structure to more readily accept that force.
    Certainly the move to a holistic approach of foot disorder Mx has had demonstrable benefits- i can recall a case presentation of a young athlete with chronic medial tibial stress syndrome- her pedal mechanics appeared to be well controlled with orthoses yet she still had significant pain. When a Physio assessed her, she demonstrated significant low back and pelvic instability. The introduction of a programme aimed at improving her core stability subsequently completely resolved her symptoms- thus perhaps we are still too obsessed with the foot as the root (no pun intended) of all evil when it comes to lower limb pathology. :eek:
    Certainly, as has been raised a number of times, we are in (or at least coming to) a position of widely questioning the biomechanical models we studied at uni an hence we are in the process of becoming a true science rather than an art. :D
    Glenn
     
  21. Daryl, Craig and Others:

    Good to see you contributing Daryl. Hope you had a nice Christmas and holiday season.

    Mert Root's contributions to our understanding of foot biomechanics is well known. However, to put his comments into a more modern biomechanical perspective, I would say that foot orthoses should apply moments that are in the opposite direction to the pathological moments that are causing the tissue injury or abnormal gait function in the patient. This is more precise than saying "controlling the last degree of pronation". In addition, this forms the basis of how I treat my patients clinically with foot orthoses.

    I agree that Irene McClay-Davis and coworkers have done some very fine research regarding the alteration of joint moments with foot orthoses. Anne Mundermann and coworkers' orthosis research also supports Irene's findings.

    I also agree that the midfoot and midtarsal joint kinetics are extremely important and I believe that kinetic modelling and finite element modelling will greatly help us understand pathology in this region of the foot.

    In regards to developing better research, I think that using only maximally pronated feet with medially deviated subtalar joint (STJ) axes in one group makes more sense that dividing research groups based on "calcaneal position" or "forefoot to rearfoot relationship". Considering the residual pronation moments and sinus tarsi interosseous compression force will be much higher in magnitude in individuals with medially deviated STJ axes, I would think that these individuals would respond much differently to foot orthoses than those feet that have more normal STJ axis spatial location and do not stand in the maximally pronated STJ position.

    Thanks for your stimulating comments, Daryl.
     
  22. Robert D. Phillips DPM

    Robert D. Phillips DPM Welcome New Poster

    Hello Kevin,

    As always, you have some good points to make. I do not disagree with the ideas about moments around the subtalar joint axis. I likewise utilize such thinking in many of my patients.

    As I approach the patient, though, my thinking always goes like this: 1) what anatomical structure(s) are painful? 2) What type of mechanism could produce such pain? (i.e. tension, compression, etc.) 3) Why is the mostly likely mechanism occurring? (pronation of the STJ, weakness of the peronei, etc.) 4) What are the goals of the orthotic therapy? The more specific I can identify the goals of therapy, the more likely I am to achieve those goals and have a happy patient.

    While orthotics always change moments around at least one joint of the foot (actually any pad or rock in the shoe will change the moments around at least one joint of the foot), sometimes my only goal is a redistribution of pressure. You have probably noted how "rigid" orthotics alleviate pressure under the calcaneal tubercle. Maybe that's all I need to do, and I don't even worry in that case too much about how much the moments around the STJ axis are being changed. Sometimes the orthotic only decreases the plantarflexion moment around the midfoot joints being created by the plantar intrinsic musculature in early propulsion. Again in this case no attention is being paid to the STJ axis moments. As you have probably already noticed, not everyone with heel pain is a pronator, yet orthotic therapy seems to help a great many that seem to have little if any abnormal rearfoot pronation.

    My comments about division of feet were intended not to be a precise suggestion, but only to demonstrate how little attention is paid to specific foot types or etiologies of the abnormal pronation or supination in most of the orthotic studies. Usually what we get is a statement like this, "XX number of subjects were chosen. All were healthy with no symptoms in their feet and no history of injury..." There is no indication of what types of feet were examined, whether they looked only at feet with laterally displaced calcanei, medially displaced STJ axes, forefoot varus feet, feet with greater than 20 degrees of frontal plane movement around the MTJ, or any other of a number of proposed foot types. Therefore, with such a broad spectrum of foot types in the study it may not be possible to statistically prove or disprove the hypothesis of the study. The possibility of type 2 errors seems to be much higher than the power studies would predict.

    Again thank you for your important comments. :) I'm pretty much in the same track you're in about moments and I appreciate the tremendous work being done by you and the many others out there to put more mechanics into biomechanics.

    I trust that you and yours had a great holiday season. I will try to make a few more postings in the future than I have done the past year (if I can get time away from printing so many pictures of the granddaughter - now I know why research productivity decreases after the grandchildren come).

    Best of wishes for 2005
    Daryl

    P.S. - I would like to propose a couple of questions:

    1) Is it ever possible to stand with all the plantar muscles of the foot relaxed, and have any of the joints of the midfoot (MTJ, CNJ, MCJ) not dorsiflexed to their end range of motion? If so, where are the plantarflexion moments coming from that would equalize the dorsiflexion moments being placed around these joint by the GRF?

    2) With a Kirby skive, is the calcaneal fat pad directly above the skive displaced medially or laterally? How could we prove or disprove any statements about movement of the calcaneal fat pad?
     
  23. Orthosis function

    Daryl,

    Good to hear about the grandchild being enjoyed by grandfather. My oldest son got married this summer so I'm probably not too far behind...but in no great rush at this time to reach your elder status. :)

    Your approach to foot orthosis therapy is identical to the one that Eric Fuller and I are writing about currently in a chapter on Tissue Stress and STJ Rotational Equilibrium. Your paragraph above is almost identical to one of the tables included within the chapter. Seeing that we think nearly identically in this regard pleases me greatly. I greatly respect your knowledge and opinions and have always looked up to you as one of the leaders of biomechanics within podiatriy within the US, even though we have had our share of animated discussions in the past.

    I don't have time now to answer your other questions but, when I have time, I will try to get around to doing so. Please give my regards to the family.
     
  24. Dary's Questions

    Here are my answers, Daryl.

    1) I would imagine that the plantar intrinsic muscles are not necessary to be firing at all times but are probably recruited intermittently to help reduce the tensile loading forces on the plantar ligaments of the midtarsal joint (MTJ) and other midfoot joints. I think that we should not talk about "dorsiflexed to end range of motion" for the joints of the MTJ and midfoot since their position will be very dependent on the prevailing dorsiflexion and plantarflexion moments occuring across them during weightbearing activities. The MTJ and midfoot joints should be thought to be more "springlike" in that they will be able to allow the foot to deform more as there is more dorsiflexion moment applied across these joints by ground reaction force (GRF). Plantarflexion moments for the MTJ and midfoot joints come from plantar ligament tensile forces, plantar intrinsic contractile activity, contractile activity of the peroneus longus, flexor digitorum longus, flexor hallucis longus and posterior tibial muscle and plantar fascial tensile forces.

    2) I don't know whether the calcaneal fat pad significantly displaces medially or laterally with the medial heel skive orthosis modification. I would guess that if it does then it is due to prevailing medial-lateral shearing forces acting on the skin that does not also simultaneously affect the calcaneal position on the orthosis plate. I am not so concerned about movement of the calcaneal fat pad but am more concerned about the kinetics of what I am doing and how this will affect the symptoms that my patient has, how comfortable they will be with the orthosis and the patient's overall gait function.

    Good questions, Daryl. Have you been doing anything more with Erin's dynamic gait replicator?
     
  25. Atlas

    Atlas Well-Known Member

    Great thread.

    Craig. In view of Gardner's rule, I presume that perhaps most of these symptoms would have been intrinsic to the foot.

    On the other hand, if proximal (eg.knee) symptoms were altered without detected changes in rearfoot motion, could therapeutic success be attributed to velocity changes? Was velocity of the rearfoot measured in addition to kinematics? Perhaps timing is a small part of the big picture. Common-sense suggests that musculo-skeletal structures work harder to counter a faster moving entity at the end-point (of movement) alone.

    If I was a baseball catcher or wicket-keeper, first my hands would prefer to catch a slower ball. But failing that, my hands would prefer to meet the fast projectile earlier and move my hands back with the ball, and hence decelerate it over the longest period possible. Perhaps this is one way an orthotic becomes therapeutic without making a significant change to total movement. If the last phase of rearfoot motion is decelerated, then the eccentric demand of the rearfoot supinators would decrease, and the velocity of internal leg rotation would decrease. Is this connected to Root's final degree of pronation, as a previous poster raised?


    Of course my little theory would be blown up if EMG studies (of the rearfoot pronators) and velocity studies (of the rearfoot motion) were assessed during the same study and were 'unchanged' also; despite symptomatic reduction.
     
  26. GarethNZ

    GarethNZ Active Member

    Hi Craig,

    I would be interested to know what structures were the ones identified as causing discomfort for the patients involved in you results

    What sort of activities were they involved in? Physical activity or mainly sedentary?

    I would also be interested in knowing how you did your rearfoot measurements? Were these in static stance or via functional measurements?

    We have noticed a similar result, but only for people suffering from Plantar fasciosis. Their rearfoot mechanics (and most other within the foot) have been disregarded and by treating patients pain there has been more confidence put back into our treatment.

    regards,

    Gareth
     
  27. Craig Payne

    Craig Payne Moderator

    All had insertional plantar fasciitis. We will soon be repeating the methodology in PFPS to see if the parameters that need to be altered are the same (I don't believe they will be)
    All sorts
    Dynamic 3D
     
  28. Atlas

    Atlas Well-Known Member

    Plantar fasciitis/fasciosis, in my clinical experience is invariably assisted (at least short-term) by low-dye taping. What does low-dye taping do to rear-foot kinematics? Other than restrict the range closer to neutral position, probably very little.

    What low-dye taping does do, and this perhaps supports Phil's theory, is that is has more of an influence on the mid and forefoot. I envisage that low-dye taping unquestionably removes tension from the plantar fascia structure, without the direct pressure exerted by a device without groove.

    Low-dye taping, I envisage also pulls the 1st ray into plantar-flexion; and I assume the other rays...hence reducing tensile stress on FHB.



    (Low-dye) taping isn't respected academically, in view of the consensus (I disagree with) that tape slackens in 20 minutes; but design me an orthotic device that does what low-dye taping does, and I will buy it.


    Back to the topic now. Craig's study could not detect significant changes in RF motion in effective orthoses for plantar fasciits. This is mirrored clinically, IMO, due to the potent (albeit short-term) effect of low-dye taping on plantar-fasciitis; despite an assumed mild rear-foot influence.
     
  29. Craig Payne

    Craig Payne Moderator

    Low dye strapping lowers the force to get the windlass established to about 10-20% ---- massive reduction ---- imagine the forces then going through the plantar fascia with the tape on and the effect of that massive reduction of force through the injured tissue.
     
  30. Atlas

    Atlas Well-Known Member

  31. Atlas

    Atlas Well-Known Member


    Typo. I meant FDB....not FHB.
     
  32. Craig Payne

    Craig Payne Moderator

    It reduced it by 80-90%, down to 10-20% of the original force - sorry for the confusion.
     
  33. As Craig noted in his research, the Low-Dye strapping reduced the tension in the plantar fascia by 80-90% when measuring the force to establish the Windlass Effect of Hicks. This makes sense when you model the foot as I have previously explaining the biomechanical etiology of functional hallux limitus (Kirby, KA: Foot and Lower Extremity Biomechanics II: Precision Intricast Newsletters, 1997-2002. Precision Intricast, Inc., Payson, AZ, 2002, pp. 139-152).

    Low-Dye strapping causes a anteriorly directed force on the plantar calcaneus and a posteriorly directed force on the anterior forefoot. These two forces will cause a rearfoot dorsiflexion moment and a forefoot plantarflexion moment, especially when the strapping is exerting a large tensile force on the skin of the foot (such as when the foot is in the late midstance phase of gait).

    Since the plantar fascia, like the Low-Dye strapping, also causes an anteriorly directed force on the plantar calcaneus and a posteriorly directed force on the anterior forefoot, it likewise creates a rearfoot dorsiflexion moment and a forefoot plantarflexion moment. Therefore, the Low-Dye strapping will reduce the tensile force on the plantar fascia since the Low-Dye strapping, basically, performs the same mechanical function as the plantar fascia.

    This is the beauty of understanding the joints of the foot and lower extremity by using the concept of moments and rotational equilibriium: many therapeutic modalities may be explained mechanically much more precisely than would be possibe without their use.
     
  34. Atlas

    Atlas Well-Known Member

    The forefoot plantarflexion moment made sense to me, but you have opened my eyes to the rearfoot dorsiflexion moment provided by taping.


    My original rearfoot mindset regarding the efficacy of low-dye taping of plantar fasciitis conditions centred around reducing the excursion of the medial tubercle. The plane of excursion would of course depend on the horizontal/vertical position of the STJ axis. My original rearfoot mindset was low-dye taping reduced the total excursion of the origin, hence the therapeutic influence on the rearfoot.

    But I have ignored and/or not come across the rearfoot dorsiflexion effect of L.D.taping; perhaps at my peril.


    I had almost come up with a 'rule' that suggested if L.D.taping is therapeutic, perhaps a root +/- modified device would suffice.

    Now that you have got me on a rearfoot dorsi-flexion wavelength, I might have to dilute the rule as other devices and modifications dorsi-flex the rearfoot more potently.
     
  35. Mechanical Effects of Low-Dye Strapping

    Low-Dye strapping will also cause a mechanical effect on the subtalar joint (STJ), however this effect is weaker than its effect on the midtarsal joint (MTJ). If the strapping can prevent flattening of the medial longitudinal arch (MLA), then the increased ground reaction force that occurs plantar to the medial metatarsal rays will cause increased STJ supination moment (or decreased STJ pronation moment).

    Certainly the rearfoot dorsiflexion moment produced by Low-Dye strapping is very important along with its ability to produce a forefoot plantarflexion moment. The magnitude of rearfoot dorsiflexion moment and forefoot plantarflexion moment produced by the strapping (and the plantar fascia, for that matter) will be dependent on the height of the longitudinal arch of the foot. The higher the arch, the greater the moments. In a very flat arched foot, virtually no rearfoot dorsiflexion moment or forefoot plantarflexion moment will be produced by the strapping (and again, the same goes for the plantar fascia).

    I think many clinicians make the mistake to assume that if Low-Dye strapping works, then foot orthoses should work just as well. Foot orthoses work by modifying the ground reaction forces on the plantar foot (all compression forces) whereas Low-Dye strapping works by adding tensile forces to the skin of the foot to cause its mechanical effect. It is for this reason that Low-Dye strapping generally is sometimes more effective for symptoms caused by excessive arch flattening moments, such as plantar fasciitis, than foot orthoses are.
     
  36. Low dye taping and rearfoot motion

    Sorry, bit late on this!

    Harradine PD, Herrington L, Wright R. The effect of low dye taping upon rearfoot motion before and after exercise. The Foot. 11(2):2001. p57-61

    We found during the initial 60% of stance phase rearfoot motion (pronation angle, max pronation and velocity of pronation) was not significantly altered by Low dye taping. Intial RCSP was more inverted, but this was lost after a brief duration of treadmill walking.

    I've been using the F-Scan in-shoe for a while now and find low-dye taping increases 1st MPJ loading and makes force time curves much more 'm' shape in the symptomatic cases I see. Interesting how the windlass can appear to work more effectively without apparently changing rearfoot position or motion.

    Paul Harradine MSc BSc(Hons) CertEd
    Podiatrist / Director
    The Podiatry and Chiropody Centre
    Cosham, Portsmouth, UK
     
  37. Paul:

    If the primary effect of the low-Dye taping is to cause a forefoot plantarflexion moment (with probably more effect on the medial column than lateral column) then your F-scan results make sense. The low-Dye taping crosses the midtarsal joint (MTJ), and does not cross the subtalar joint (STJ). Because of this, it will have much more mechanical impact on the MTJ than on the STJ. That is not to say that it will not have an effect on the STJ, but it will likely be much less visible.

    A good example of how the windlass can be changed without an apparent change in rearfoot position or motion is to take a foot that is maximally pronated at the STJ in relaxed bipedal stance, and then add some extra STJ pronation moment to it by having, for example, the foot stand on a 10 degree valgus wedge.

    Has the rearfoot position changed? No.

    Has the rearfoot moved? No.

    However, now try a Hubscher maneuver on both feet and which foot condition do you think will require more force to dorsiflex the hallux? The one with the valgus wedge. The supination resistance test will also likely require more force (Kirby KA, Green DR: Evaluation and Nonoperative Management of Pes Valgus, pp. 295-327, in DeValentine, S.(ed), Foot and Ankle Disorders in Children. Churchill-Livingstone, New York, 1992).

    It is the kinetics of the foot that will alter the kinematics. However, the kinetics can change without an alteration of the kinematics. Thinking in terms of rotational equilibrium and kinetics greatly helps in understanding these findings.
     
  38. Hi Kevin

    I completely agree with your reply. Infact, we demonstrated your valgus posting example to some extent in:

    Harradine PD & Bevan LJ : The effect of rearfoot eversion upon maximum hallux dorsiflexion. Journal of the American Podiatric Medicine Association 9(90);2000

    When fitting orthoses though, do you still like to see an 'improvement' in rearfoot position and motion? Or do you look for static test improvements such as Hubscher standing on the appliances etc?

    Regards

    Paul Harradine
     
  39. Craig Payne

    Craig Payne Moderator

    Thats what started this thread....we have found NO correlation to dynamic changes in rearfoot position/motion and clinical outcomes (ie symptom improvement)
     
  40. Hi Craig, thanks for the reminder on how the thread started.

    It isn't however the question I asked Kevin. I was interested if a podiatrist with the wealth of clinical experience such a Kevin still 'likes to see an 'improvement' in rearfoot position and motion'. I then asked about static tests on orthoses (unshod!) such as the Hubscher.

    Sorry for any confusion

    Paul
     
Loading...

Share This Page