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Plantar fascia strectching - a finite element analysis of the windlass

Discussion in 'Biomechanics, Sports and Foot orthoses' started by NewsBot, May 28, 2008.

  1. David Smith

    David Smith Well-Known Member

    Dieter

    When I read the paper abstracts I interpreted it as the following.

    One study is talking about total force in respect to single leg stance (latter) and the other in respect to resting bipedal stance (former).

    Therefore 2 x 42.9% per foot = 86% total b/w, which is not too dissimilar to 97% of b/w in the other study.

    Cheers Dave
     

  2. Neil Sharkey and colleague's study was done on single cadaver limbs in a gait simulator with only the extrinsic muscles of the foot loaded, not the intrinsic muscles. This probably leads to a slight overestimation of the plantar fascial peak tension (0.97 x BW is the peak tension, not the average tension in plantar fascia during gait).

    The other study, as David points out, was an FEM study on bipedal standing at 1/2 BW for each foot. However, if the patient leans forward, plantar fascial tension will increase, if the patient leans backward, plantar fascial tension will decrease. There are many variables that control plantar fascial tension, with longitudinal arch height being a very important one (i.e. lower arch height=more plantar fascial tension, higher arch height=less plantar fascial tension).
     
  3. drsarbes

    drsarbes Well-Known Member

    "Here are the pathologies/symptoms that may occur due to medial plantar fasciotomies that are based on cadaver research and finite element modelling research:

    1. Strain in medial plantar intrinsic muscles (i.e. medial arch fatigue).

    2. Strain in plantar ligaments of medial column (i.e. medial arch tenderness)

    3. Decrease in digital purchase force in medial digits (i.e. medial hammertoe development)

    4. Increase in plantar pressure in medial lesser metatarsal heads (i.e. 2nd and 3rd metatarsalgia).

    5. Increased strain in posterior tibial muscle and possibly flexor hallucis/flexor digitorum longus muscles (i.e. PT, FHL, and/or FDL tendinitis).

    6. Increased bending moments in shafts of medial lesser metatarsals (i.e. 2nd and 3rd metatarsal stress reaction/stress fracture).

    7. Decreased supination in late midstance and early propulsion (i.e. gait finding)."
    ========================
    Hi Kevin:

    Well, it's a long list. Frankly I've never seen any of them post operatively, at least to the point where there was a clinical effect.

    It takes me approximately 10-15 minutes to perform a flouroscopic aided fasciotomy/heel spur resection. The patient is in a surgical shoe X 7 days with decreased activity X 21 days.
    I do not want too candy coat my results, but I never hesitate to suggest this procedure on patients with chronic fasciits.

    If you all get better results than I do with biomechanical treatment, wonderful. But I want to go on record as stating that, when done properly, fasciotomy/heel spur resection is a predictable, very successful, quick healing procedure.

    Steve
     
  4. Steve:

    Since you claim your surgical results are so good with partial plantar fasciotomy, then why not do your plantar fasciotomy initially on all your patients with plantar fasciitis instead of bothering with "biomechanical treatment"? What is stopping you from doing the procedure more since you obviously see no problems with performing this procedure on a routine basis?
     
  5. Dieter Fellner

    Dieter Fellner Well-Known Member

    Steve,

    And this is the hub of the issue. I also would normally only get to see those patients who have been tried on and failed to respond to the usual conservative treatments.

    I still remain to be convinced of the absolute value of patient directed PF stretching. And I am still awaiting a description of the type of exercise that we can be reasonably sure could generates the kind of tension required to stretch the fascia any more than regular standing/walking/running could.

    Patients often are advised to stretch out the PF after sleeping , before walking. Usually this involves bending the toes back to stretch the fascia. Does anyone really suggest this produces as much pressure as say 240lb of body mass ? This doesn’t make sense. Some patients seem to report if this is done, there is a dampening effect on the post static dyskinesia (PSD). Well yes, sometimes but even in those cases, so what?

    Another conundrum – with the night splints applied and the fascia maintained on stretch patients will report PSD, all the same. Why ?

    Some studies suggest the PF has inherent elasticity and that is stretchable. In this thread, the emphasis is placed on showing that it is capable of such activity. Personally, I never had any reason to doubt it. But that is till missing my point. No study has confirmed that any patient directed exercise can stretch the PF to make a clinical difference. And usually this activity, when it is recommended (and assuming patients will actually follow advice !) this will form only part of a more comprehensive treatment regime. Unfortunately it is not a (?yet) a quantifiable variant to lend itself to measurement in vivo. And cadaver studies – well you can extrapolate only so much from that.

    It is that irksome 10-15% of patients who will resist all the regular non surgical options. I have found a measure of additional success, with cryosurgery, and probably would in many cases now recommend this before invasive surgery. But failing that, I am with you Steve, surgery has a place in the tool box.

    If anyone can claim they can cure ALL cases of PF, without ever considering surgical intervention, well this must surely cast some doubt on their credibility. I am sure no-one here belongs in that category ?
     
  6. Those podiatrists that claim that any treatment for plantar fasciitis is 100% effective in all cases with no incident of other pathology or sequellae, whether it is conservative or surgical treatment, are only kidding themselves. I also do surgical plantar fasciotomy procedures in selected patients with very good results. However, I don't kid myself in thinking that plantar fasciotomy doesn't have the potential to cause other mechanical problems in the future. Why? Because surgical plantar fasciotomy has been shown to effect the mechanics of the foot in numerous scientific research studies. There is no question about this.

    The question comes in whether the surgeon doing the partial plantar fasciotomy is actually paying attention to those small changes in gait function or development of other pathology for months and months after surgery that may occur. Rather, are they like most surgeons, asking the patient only if their plantar fascial pain is resolved and not calling their patients back for followup unless they have heel pain again, not wanting to be bothered in their process of lining up more patients for more surgeries as the days, weeks, months and years roll by.

    This all reminds me of the orthopedic surgeons who, for years, did Keller bunionectomies and claimed consistently great results with their Keller bunionectomies in preventing bunion regrowth but conveniently ignored the second metatarsal stress reactions/stress fractures, painful sub 2nd metatarsal head callouses and lack of hallux purchase following Keller bunionectomies.

    Like I said before, you may have not seen it before, but it has seen you plenty of times.
     
  7. Mart

    Mart Well-Known Member

    The attatched study does'nt address the issue of tension as you are hoping . . but never the less provides a reasonably sized prospective RCT for effects of the technique

    hope that helps

    cheers

    Martin

    The St. James Foot Clinic
    1749 Portage Ave.
    Winnipeg
    Manitoba
    R3J 0E6
    phone [204] 837 FOOT (3668)
    fax [204] 774 9918
    www.winnipegfootclinic.com

    View attachment Tissue-Specific Plantar Fascia-Stretching Exercise.pdf
     
  8. drsarbes

    drsarbes Well-Known Member

    "The question comes in whether the surgeon doing the partial plantar fasciotomy is actually paying attention to those small changes in gait function or development of other pathology for months and months after surgery that may occur"

    Hi Kevin:
    I assume this was directed at me. It's OK, you can name names, no one is innocent here!

    Actually I do pay attention, and no I do not see biomechanical problems in my post fasciotomies.
    You can accept this or not, I really don't care. It doesn't change the fact.

    Practitioners, in time and experience, tend to gravitate towards treatments that work for them. There certainly is an ART form to this. I think we all like to think we are more scientific in our approach, particularly if we are an academic, but in the end we do what has proven to be successful.

    My dad always told me not to argue with success. Studies are great, and they tend to keep a lot of people busy, but in the end the only thing that really matters in the clinic is what actually works. Sometimes this can be supported or accounted for by studies, sometimes not.

    That's my 2 cents for this beautiful Wednesday morning.
    Steve
     
  9. Frederick George

    Frederick George Active Member

    Dear Dr. Sarbes

    It's good to hear of your results with the fluoroscope aided fasciotomy/heel spur resection. I did the study with NASA using the original prototype mini C-arm (lixiscope) for various foot surgeries, including heel spur. At that time, in the
    1980's, some of my colleagues didn't think it was possible, and since they couldn't do it, obviously no one could.

    I too have excellent results with the surgery, with only occasional nonspecific lateral midfoot pain of 2-4 weeks duration p/op. I think all those complications are theoretical, probably based on some simplistic two dimensional model.

    I generally try Root/Blake orthotics with a plantar fascia accommodation. These work most of the time, and the rest of the time I do the surgery. I only inject if someone needs temporary relief, a competition, etc.

    Quite a number of patients come to me because other treatments haven't worked. They get tired of stretching, icing, night splints, orthotic adjustments, NSAIDS, etc. They don't want their foot to rule their life.

    I was amused when you were asked why you don't do surgery 100% of the time. That speaks to the old adage about the hammer.

    On a related issue, in 1983 the Chinese showed us a study they were doing on intracalcaneal pressure. They measured the pressure preop, and post decompression. The pressure dropped, and the relief of symptoms was proportional to the measured drop in pressure.

    Good to hear about your fluoroscopic surgery. I think it works much better than an endoscope.

    Cheers

    Frederick
     
  10. drsarbes

    drsarbes Well-Known Member

    " I did the study with NASA using the original prototype mini C-arm (lixiscope).."

    Hi Frederick:
    The LEXISCOPE!!!! I loved that thing!
    Hand held - greenish hue - easy to use. I thought at the time that was out that by now EVERYONE would have a hand help affordable "micro" Fluoroscope in their clinic coat pocket.

    If I recall the problem was the cost of replacement parts. Wasn't there a component that needed to be replaced periodically that cost almost as much as the entire scope?

    We had a prototype in the clinic in Chicago for a few months when I was a student. It was just the ideal diagnostic tool (compared to trying to use our xray vision!)

    What ever happened to them?

    Steve
     
  11. Frederick George

    Frederick George Active Member

    Hi Steve

    That's the one. The original Lixiscope (Low Intensity Xray Imaging Scope) had a small piece of radioactive Iodine for a source, which with it's short half life, was only good for about 6 months. Lo I Yin PhD, an astrophysicist with NASA invented it, and brought it with him for the lixiscopic surgery study. Lo I (Louie) and I worked on it in my shop to make it easier to use for the surgeries. We devised a support that worked for the different surgical approaches, and added a macro video camera and monitor. The second generation lixiscope had a weak xray generator to eliminate the isotope cost. Fluoroscan developed the commercial product using NASA's technology.

    The nice thing about the technology is that compared to an old C-arm, the xray exposure to the patient and doctor is very low because of the microchannel plate (nightscope) gain.

    Are using a mini C arm in your surgeries? It has a lot of uses.

    Nice reminiscing.

    Cheers

    Fred
     
  12. drsarbes

    drsarbes Well-Known Member

    Hi FRed:
    I stand corrected on the spelling.
    So why wasn't the hand held version developed further???????

    I use a mini C arm approximately 5-6 times per week in surgery. Even with the low RAD I try to limit the minutes, but most cases average over 2 minutes. I don't wear an apron although I make my assistant wear one and anyone in childbearing age in the room wears one. I also try never to use it just for documentation or if I REALLY don't need it (i.e., bunions, post op documentation, etc...) that's what we have portable x-rays in recovery for!

    I sometimes get stuck with the Regular C-Arm, and with the large surface I find it easier to just place the foot/ankle right on the c-arm and work there instead of through the table.

    STeve
     
  13. David Smith

    David Smith Well-Known Member

    Dr Sarbes

    Re: Lixiscope - Lexiscope

    Ah! the Lexiscope - Yes aren't you getting mixed up with the LexOscope, which was the fiendish device invented and manufactured by Luther Corp and designed to observe Superman at velocities faster than the speed of sound. It contained a small isotope of green Kryptonite and when used in combination with the LexOray it was supposed to shoot down a supersonic aircraft which would then crash into the Daily Globe building. It all went wrong at the last minute (like it always does) and production was terminated shortly after.

    Sincerely Dave:wacko:
     
  14. only scanned this but to "really" stretch this structure long-term don't you need to induce plastic-set?
     
  15. MelbPod

    MelbPod Active Member

    I had a guy in over the past few weeks with plantar fasciitis/osis, hx 6 months.
    I have tried various conservative treatments (footwear change, stretching, taping..) with slight symptom reduction. ordered some non-casted orthotics with 1st ray accomodation and midfoot support to promote windlass.
    In the meantime pt visited his regular masseur, she got stuck in to his plantar fascia and a few days later when he came to collect devices he was symptom free!

    could somebody explain the pathomechanics or reasons for this resolve?

    Regards

    Sally
     
  16. Dieter Fellner

    Dieter Fellner Well-Known Member


    Martin,

    Thanks for the attachment. The article describes the exact technique that I have been advocating to patients for years. As you noted this doesn't address the conceptual issues I posed. So the patient puts under tension the PF bending back the great toe. The PF is put under tension just the same standing and walking. So what else is going on ?

    The article certainly looks like good science, right ? Is the gravitas attached to RCT's in this arena worthy - I harbor deep mistrust ! There was a time when I was comfortable accepting this type of evidence. Is it definitive ? Or is it yet another opinion dressed up as science ? Seems to me the researchers set out to provide the answers they expected - and the 8 week follow up, among other, probably isn't enough. And are we now to stop recommending Achilles stretches ? And it would have been nice to have as a control group a sham treatment – just to know what percentage get an improvement in symptoms just the same ? And ….

    Yes, I know, research like this one is the foundation of scientific enquiry. But we also know that patients belonging in the 10% group are likely to get real motivated to do something about this niggling pain. Lest we forget the gold standard of research, double blind, randomized, controlled etc – it was designed for drug research. The only real measure here is a subjective account from the patient about pain…. Meaningful or meaningless – this alone can be debated endlessly.

    I also noted the patients got to see an educational video on plantar fasciitis. I wonder just how many would have picked up a tip or two beyond the treatment instructions specific to the research protocol ? This can be facilitated also by giving patients the opportunity to network in the clinic. How many combined those treatments previously recommended with the stretching ‘just to be sure’. Isn’t it reasonable to assume a patient’s first priority is to rid themselves of the pain, over any allegiance to the research project ? Participants aren’t supervised to swallow just one pill. Who can really know what happens outside of the hospital ? Statistically how many such patients are required before the results get to be skewed ? It is simply impossible to control the variables

    But hey, it’s a neat study and damn it I like it. And will I continue to tell my patients about it - you bet’cha !
     
  17. Dieter Fellner

    Dieter Fellner Well-Known Member

    Sally,

    Man, don't you just hate it when that happens ? Makes the clinician look like a bumbling idiot !:bang:

    Whilst hypotheses abound, in many aspects, the exact cause of plantar heel pain remains an enigma. But I don't think there need to be a great mystery behind your patient's pain relief. Firstly this condition in the great majority of patients burns out spontaneously. I suspect, with or without treatment. Now, that will happen and whoever or whatever last made contact with that foot will be hailed to provide the miracle 'cure'. Until the pain comes back.....

    I am sure a massage therapist can provide an explanation of why, say deep friction massage, can help with heel pain. Let's assume for example the pain is neurogenic in origin and related to compartment syndrome affecting the nerve branches coursing through the porta pedis - maybe some chronic trauma related adhesion, or some such novel thing. And after a good pummeling from the therapist's rod like digits, the adhesion is loosened, and the nerve pressure abates.

    It seems likely your patient should, probably, still have orthotics to mitigate those mechanical forces that can cause a relapse. That also can happen !
     
  18. Mart

    Mart Well-Known Member

    Hi Deiter

    I agree with most of your points and I guess that is the nature of science; it is a slow. frustrating, arduous, meticuous process. Too many questions, too little time and in terms of knowledge, seems to make "truth" exponentially unatainable. Dave Smith has made some excellent comments in his phillosophical ramblings, he does find solace however by noting that the world might be unengaging if things were otherwise, a sobering and non the less optimistic view pint which I am quite happy raise a glass to.

    One of the ideas which I keep harping back to ion my own mind is trying to figure out selective diagnostic nerve blocks to try and isolate the pain generator(s) in those with PHP, I think this might be a useful tool in understanding the nature(s) of this complaint. With your sugical background do you have any notions of differentiating "bone", "periosteal" and "musculo-tendinous" components of this region with small precisely located nerve blocks? Perhaps this is an unrealistic idea.

    cheers

    Martin


    The St. James Foot Clinic
    1749 Portage Ave.
    Winnipeg
    Manitoba
    R3J 0E6
    phone [204] 837 FOOT (3668)
    fax [204] 774 9918
    www.winnipegfootclinic.com
     
  19. Dieter Fellner

    Dieter Fellner Well-Known Member

    Martin: :eek:

    It is not for me - a mere mortal - to attempt such a thing ... it is possible that walking among us (?more aliens) there are those blessed with such outer worldly skills.

    Me, I'll settle for a Bud ...:drinks
     
  20. Frederick George

    Frederick George Active Member

    Hi Steve

    The hand held lixiscope just needed two flashlight batteries to charge the microchannel plate, and used an Iodine isotope for the xray source. But isotopes cost a lot, and wear out quickly. A regular xray source requires high voltage electricity and doesn't like being banged around. And is larger. Hence the mini C arm.

    I don't think your mini C arm is throwing out as much radiation as you think. Because the NASA mini C arm wasn't approved, we had the California radiation people in to examine and approve it for the experimental surgery. They couldn't detect any scatter or back scatter with their instruments, outside of the beam field. The radiation exposure to the patient was much less than the postop xray. 15 minutes of mini C arm use was equal to one 8X10 casette film with double intensifying screens. So you may just want to use it for documentation instead of the normal postop xray.

    Now, with the old fashioned fluoroscopes, you want to wear lead!

    Cheers

    Fred
     
  21. drsarbes

    drsarbes Well-Known Member

    Hi Fred:
    From '95 to '98 I wore a Radiation Badge in surgery at one of the hospitals I use. At that time I was doing around 15-20 minutes a week usuage. The readings were always trace or zero so I stopped wearing them.
    I still feel uncomfortable in the OR having women of child bearing age not wear an apron, so I normally suggest they do. If anyone is pregnant they wear one or leave the room when I use it.

    I don't want to cause any harm, plus, here in the U.S.A. there are 2.6 lawyers for every patient!!!!

    I've used Mini C arms now for HOURS and HOURS. I'll let you know if my gonads start to glow in the dark.
    Steve
     
  22. NewsBot

    NewsBot The Admin that posts the news.

    Articles:
    1
    Here is another publication by teh same authors that started this thread:

    Nonlinear Finite Element Analysis of the Plantar Fascia due to the Windlass Mechanism.
    Cheng HY, Lin CL, Chou SW, Wang HW.
    Foot Ankle Int. 2008 Aug;29(8):845-51.
     
  23. NewsBot

    NewsBot The Admin that posts the news.

    Articles:
    1
    Assessment of mechanical strain in the intact plantar fascia
    Ross A. Clark, Andrew Franklyn-Miller, Eanna Falvey, Adam L. Bryant, Simon Bartold, and Paul McCrory
    The Foot Volume 19, Issue 3, September 2009, Pages 161-164
     
  24. NewsBot

    NewsBot The Admin that posts the news.

    Articles:
    1
    Finite Element Modeling of the Plantar Fascia: A Viscohyperelastic Approach
    Knapp, Alexander, (2017).
    UNF Theses and Dissertations. 740.
     
  25. NewsBot

    NewsBot The Admin that posts the news.

    Articles:
    1
    Application of finite element method in biomechanical study on plantar fasciitis
    Liu Jiao-jiao, Zhu Xiao-lan, Liu Hui
    Source
     
  26. David Smith

    David Smith Well-Known Member

    Oh how I miss the days of such great discussions such as this one
     
  27. NewsBot

    NewsBot The Admin that posts the news.

    Articles:
    1
    Cadaveric Analysis of Plantar Fascia Tension and Windlass Mechanism and Development of Plantar Fascia-Specific Stretching Device
    Kaveh Momenzadeh, MD, Caroline Williams, BA, Patrick M. Williamson, ...
    Foot & Ankle Orthopaedics January 22, 2022
     
  28. NewsBot

    NewsBot The Admin that posts the news.

    Articles:
    1
    Development and Clinical Evaluation of a Novel Foot Stretching Robot that Simultaneously Stretches Plantar Fascia and Achilles Tendon for Treatment of Plantar Fasciitis
    Yusung Kim, Divij Bhatia, Yechan Lee, Yeonhun Ryu, Hyung-Soon Park
    IEEE Trans Biomed Eng. 2022 Feb 16
     
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