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Peroneal Tendon Dysfunction

Discussion in 'Foot Surgery' started by Dieter Fellner, Sep 8, 2005.

  1. Dieter Fellner

    Dieter Fellner Well-Known Member

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    An orthopaedic consultant has referred this case for advice.

    A 56 year old mildly overweight male Insurance Broker in good health with idiopathis pes cavus, active but not active in recreational sports, spontaneously and without antecedent trauma or history of ankle sprains, developed right peroneal tenosynovitis 4 years ago affecting within 3 months the left foot, which became the most painful. He has had steroid injections which made it worse. Physiotherapy (excercises, electrotherapy) and insoles which did not help.

    The pes cavus manifest as a high arch profile. The calcaneus is vertical. There is adequate painfree motion at the ankle, sub-talar and MTJ's.

    Surgery on the left side revealed gross synovitis which was addressed together with a z-plasty of PL in May this year. The PB was left intact as there appeared to be"some slack" in the tendon. This has not helped.

    An MRI scan revealed tears within the tendon and I assume, although the letter is unclear about this, the surgery addressed this also. I have requested XRF to check for any contributory bony abnormality e.g. enlarged peroneal tubercle. The Orthopaedic surgeon has no further ideas about how to progress his treatment.

    I have given him a lateral rearfoot wedge insole in the vain hope this will reduce the mechanical tension on the tendons but mostly to buy time to research this problem. I will be interested to know if anyone has experience of similar conditions and thoughts about further managment.

    I am speculating the cavoid foot posture might cause abnormal stress as the tendon passes along the fibular groove and possibly contributory boney abnormality in this area. Unlike Tib. posterior dysfunction which has been associated with medial conditions (diabetes, hypertension, obesity,40, female) I am unaware of any related conditions to cause PT pathology.
  2. It is my opinion that one of the most beautiful aspects about the Subtalar Joint Axis Location and Rotational Equilibrium (SALRE) Theory of Foot Function is that it provides a coherent mechanical explanation for the cause of tendon pathologies of both the major invertors (e.g. posterior tibial dysfunction) and evertors (i.e. peroneal tendinopathy) of the rearfoot (Kirby KA: Subtalar joint axis location and rotational equilibrium theory of foot function. JAPMA, 91:465-488, 2001).

    One of the lectures I have given the last few years to the second year podiatry students at the California School of Podiatric Medicine (and have given in Sydney, Madrid, Ottawa and at the Biomechanics Summer School in England) is titled "Successful Conservative Treatment of Peroneal Muscle/Tendon Disorders Using Subtalar Joint Axis Location/Rotational Equilibrium Theory". In this lecture I demonstrate how lateral deviation of the STJ axis, will cause an increased demand on the peroneal muscles during gait due to the increased STJ supination moment that is caused by the action of ground reaction force acting on the plantar aspect of a foot with lateral deviation of the STJ axis. A laterally deviated STJ axis is commonly associated with feet that have a cavus deformity, a large metatarsus adductus deformity, a high degree of "rigid" forefoot valgus deformity and/or a high degree of rearfoot varus deformity.

    Using only valgus rearfoot wedges to treat these feet with chronic peroneal tendinitis or peroneal tendinopathy is basically useless in most cases since these valgus rearfoot wedges do not cause sufficient increase in magnitude of STJ pronation moment to relieve the tensile loading forces on the peroneal tendons and bring symptomatic relief to the patient. This is because a valgus wedge placed only under the rearfoot is being placed directly under the STJ axis so that little increase in STJ pronation moment can occur from a small STJ pronation moment arm that is afforded to the valgus wedge under the calcaneus.

    However, at the forefoot, especially at the lateral metatarsal heads, there is located the area of the plantar foot that is the greatest distance lateral to the STJ axis (i.e. longest STJ pronation moment arm) so that any in-shoe wedging will cause the maximum increase in magnitude of STJ pronation moment for its given force being applied to the plantar foot. Therefore, one needs to add a valgus wedge especially under the lateral forefoot (to the digital sulcus) to see the most symptomatic relief from peroneal tendinitis/tendinopathy and to optimize the gait function of the individual.

    I typically use an orthosis, in these cases, that has a 2-4 mm lateral heel skive, is balanced with at 5-10 degrees of forefoot valgus correction, has extra medial expansion plaster (to lower medial longitudinal arch of orthosis), has a lateral arch filler on plantar aspect of lateral longitudinal arch of orthosis (to prevent lateral longitudinal arch deformation of the orthosis), and a 5-10 mm thick lateral forefoot extension (distal to the orthosis and under the metatarsal heads 2-5) that is skived into a valgus wedge with the thickest point being lateral to the 5th metatarsal heads and the thinnest being at the 1st intermetatarsal space.

    Over the past 20 years of using this modification, I have helped or cured numerous patients with chronic peroneal tendinitis/tendinopathy that have sometimes been to over 4-5 other podiatrists/orthopedists that have made "vertically balanced orthosis plates without valgus forefoot extensions" that gave little help, if not made the problems worse for these patients. I believe that these treatment failures from the majority of the podiatry profession in these unique patients comes from the failure of the traditional podiatric biomechanics theories of "STJ neutral being the ideal position of function, calcaneus will pronate to heel vertical, the foot should be supinated by the foot orthoses to neutral etc, etc, etc" to adequately explain the mechanical cause of peroneal tendinitis/tendinopathy. To my knowledge, only the SALRE Theory of Foot Function explains the wonderful treatment results provided by the large valgus wedging in foot orthoses to those patients with peroneal tendinitis/tendinopathy.

    By the way, I have heard many complaints from many of the well-known "Root purists", whose names you would all readily recognize, regarding the ideas I have presented above. However, their problems with my theories don't worry me since my patients with peroneal tendinitis/tendinopathy are routinely getting better with the techniques listed above.

    I have attached a few photos of one of these patients to show the lateral STJ axis location that is present in these patients. In this patient, the left STJ axis is more lateral and much more symptomatic at the peroneal tendons than the right. This 51 year old physician's assistant had left greater than right peroneal tendon pain and lateral ankle instability that was making him consider retirement. Within 4 weeks of receiving orthoses, with icing therapy 20 minutes BID, he was asymptomatic, after having the pain gradually increasing over the last 10 years and having had 3 sets of foot orthoses made for him by other podiatrists that either did nothing for him or made him worse.

    I hope that this will help your patient, Dieter, since developing these theories and using these treatment techniques has certainly been very gratifying to me and, even better, has helped change the lives of many of my patients duing my past 20 years of private practice.

    Attached Files:

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  3. Dieter Fellner

    Dieter Fellner Well-Known Member

    Deviant axes ...


    As luck would have it, and with little confidence in heel wedges in general, I extended the lateral wedging along the lateral border of the foot to the level of the 5th metatarsal head. The patient will be reviewed in 6 weeks to see if this is sufficient or not.

    The casting advice I will need to give more thought - I haven't casted a foot for an orthoses for the best part of a decade, focusing instead on the surgery but there should be enough detail from your description to instruct a lab appropriately, and I feel confident I can still manage a POP cast!

    Thanks for sharing your thoughts, and experience. I will relay this patients ' feedback.

  4. Make certain that the wedge is sufficiently thick under the lateral column, lateral metatarsal heads and lateral heel to cause a change in gait and a change in symptoms with walking on the first visit. Then I would see the patient back in 2 weeks to add some more lateral wedging if they hadn't made improvement. I believe 6 weeks is much too long for a followup on these patients, especially if the wedging is insufficient. Also start the patient on 20 minute, twice daily icing to the peroneal tendons. Firm midsoled shoes that are not inverted at midsole (new shoes or high top boots are preferable) are a must for optimum treatment results also.

    Let me know how he progresses.
  5. NewsBot

    NewsBot The Admin that posts the news.

    Recurrent Subluxation of the Peroneal Tendons
    American Journal of Sports Medicine 2006,
  6. NewsBot

    NewsBot The Admin that posts the news.

    Intrasheath subluxation of the peroneal tendons.
    Raikin SM, Elias I, Nazarian LN.
    J Bone Joint Surg Am. 2008 May;90(5):992-9.
  7. Bruce Williams

    Bruce Williams Well-Known Member

    while I do not disagree with your treatment protocol of this problem, I do disagree with your reasoning for why it occurs.

    Just having a lateral deviation of the STJ axis should not cause the Peroneals to be over active.

    I do not see this condition in patients until or unless they begin to have loss of MTJ integrity coupled with AJE. In most cavus foot types the 1st ray will be rigidly plantarflexed. If that case the peroneals should have a fixed response. If instead the 1st ray starts to elevate to a point that the peroneals cannot activiely keep the 1st metahead plantarflexed in late midstance then peroneal tendinosis will develop.

    As I said, the treatment protocol we use, for the most part, is the FF valgus wedging. Beware the amount of DFion that is allowed at the 4th adn 5th mets because patients can and will only tolerate maximall DFion in this region. I would suggest a soft metapad as well, and the use of a kinetic wedge modification w/ 3-6mm of ppt or poron backfill to help the 1st ray DF effectively. Finally, balance for LLD on the short side.

    Bruce Williams
  8. Bruce:

    I am interested in the mechanical reasoning behind your statement that lateral deviation of the subtalar joint axis would not tend to cause the peroneal muscles to have more contractile activity during gait.
  9. Bruce Williams

    Bruce Williams Well-Known Member


    if your reasoning were true then every patient with a cavus or cavoid foot type would end up with peroneal tendinosis bilaterally. As well, every patient with a flat foot and medial STJ axis would have increased contractile activity of the PT tendons.

    I rarely see either of these problems as a bilateral on presentation.

    Maybe you could give me reference showing increased peroneal contractile activity in patients with bilateral cavus foot structure? If you have one I will read it and let you know my thoughts.


  10. Bruce:

    Please show me where I ever said that every patient with a laterally deviated STJ axis would have increased contractile activity of the peroneal muscles or that increased contractile activity of the peroneal muscles always leads to peroneal tendinopathy. You won't find it because I never said either of those things.

    You may want to ask Craig Payne about his study on supination resistance and its correlation to unilateral lateral ankle sprains. Then we can talk about which theory explains his experimental findings the best.

    Craig, are you there??
  11. Pompy

    Pompy Member

    Hi Kevin,
    Long time browser/reader of this fantastic forum, first time poster. I was just wondering if you could possibly post a photograph or 3 of your orthoses that you would use for a patient as above. I have had a number of patients present in the last 12 months or so with Peroneal Tendinopathy and with using the SALRE theory, which I first heard about on this forum, it has certainly changed the way I have prescribed devices. As they say, a picture paints a thousand words. Thanking you in anticipation.
    Kind Regards, Scott

    P.S. Looking forward to hearing you in August at Melbourne conference.
    Last edited by a moderator: May 5, 2008
  12. Bruce Williams

    Bruce Williams Well-Known Member


    someone asked about peroneal tendinosis and you said it is b/c of a lateral STJ axis position.

    If a patient has a flatfoot adn peroneal spasticity does this mean it could be from a lateral STJ position as well?

    I do not think patients with tendinosis have overactivity of their affected tendon. I think we may come to find that tendinosis becomes an "under-use" problem, meaning the tendon becomes inactive as the problem moves from inflammatory to non-inflammatory.This is why I think you will not usually see this problem bilaterally in patients.

    The peroneals want to have the foot into position to allow easy transition from AJ pivot to FF pivot. They are a part of midfoot stability, along with the PT tendon, and are dependent on AJ ROM in midstance to be in position to continue their work after heel off when they become electrically inactive.

    If they chronically have to fight the body to do their work I think they will move from an inflammatory tendinitis to a non-inflammatory tendinosis over time.

    I asked you for a paper reference. I actually did a study, non-published, before and after AJ manipulation. We found increased peroneal activity during muscle testing after AJ manipulation in patients who had AJ equinus prior to manipulation.

    I look forward to Craigs input / insight as always.
    Cheers Kevin.

  13. Scott:

    Welcome to Podiatry Arena and thank you for your kind comments.

    I have attached a photo of a pair of orthoses that I used on one of my patients with peroneal tendinopathy. The orthoses are 3/16" polypropylene with a flat rearfoot post, 3 mm lateral heel skives, with extra thick medial expansion plaster, balanced 4 degrees everted, with a 2-5, 1/8" korex forefoot extension. The orthosis for the right foot shows the 1/8" adhesive felt wedge that I used to temporarily add increased rearfoot and forefoot valgus wedging to the orthosis in order to decrease the contractile activity of the peroneal muscle. NOtice that there is a full 1/4" of adhesive felt plantar to the lateral arch of the orthosis to prent lateral arch deformation in this patient that had peroneal tendinopathy worse on the right than on the left.

    As an aside, I find it very interesting to see how different clinicians respond in different ways to the ideas and techniques I have been teaching over many years. I often find that those clinicians who have been teaching their own ideas at seminars over the years are less receptive to taking the time to see whether the observations I have made over the years correspond to the observations that they have taken the time to make. Increased peroneal contractly activity occurs in many patients when they are simply standing on both feet. This will not be noticed unless you look at the lateral-posterior side of the ankle to see and palpate the peroneal tendons to see if they are under tonic tension. This peroneal contractile activity does not occur in all patients that have a high arched foot but does occur in many patients that have a laterally deviated subtalar joint axis. This is not a peroneal spasm since the patient has a full and supple range of motion of the subtalar joint on non-weightbearing examination. I see it approximately 3-4 times a month in my busy practice.

    Any clinician that says that tonic peroneal contractile does not occur in standing obviously hasn't looked for it in their own patients because it is much more common than one would expect and since the majority of individuals who do use their peroneal muscles to increase the STJ pronation moment during relaxed bipedal standing have no pain or pathology within the peroneal muscles or peroneal tendons. In this regard, as I said in another thread, one of my favorite quotes is "You may not have seen it, but it has seen you!"

    I'll take the time to take a better clinical photo for all the "non-believers" when I see an example in my office and I have some time to do so.
    Last edited: May 6, 2008
  14. drsarbes

    drsarbes Well-Known Member

    I'm a little confused as to what the patient's original problem was.
    Apparently he had bilateral/chronic pain in the peroneal areas, however, underwent surgery on the right only.

    Was there an acute episode?
    Were the symptoms in the right different or just more severe than in the left.
    Was there a linear tear found? If so, where was it (them)?
    Was there any evidence of peroneal subluxation preoperatively or even now?
    What's the available ROM of the STJ?

    I find the discussion of biomechanical control given by Kevin very enlightening. Thanks.

  15. Bruce Williams

    Bruce Williams Well-Known Member


    As an aside, I wanted you to know that I do read your posts.

    You said in your initial post in this section, "One of the lectures I have given the last few years to the second year podiatry students at the California School of Podiatric Medicine (and have given in Sydney, Madrid, Ottawa and at the Biomechanics Summer School in England) is titled "Successful Conservative Treatment of Peroneal Muscle/Tendon Disorders Using Subtalar Joint Axis Location/Rotational Equilibrium Theory". In this lecture I demonstrate how lateral deviation of the STJ axis, will cause an increased demand on the peroneal muscles during gait due to the increased STJ supination moment that is caused by the action of ground reaction force acting on the plantar aspect of a foot with lateral deviation of the STJ axis. A laterally deviated STJ axis is commonly associated with feet that have a cavus deformity, a large metatarsus adductus deformity, a high degree of "rigid" forefoot valgus deformity and/or a high degree of rearfoot varus deformity.

    Have a great day!
  16. Phil Wells

    Phil Wells Active Member

    Dear all

    I would like to ask a question about the plantar location of the ankle joint and its sagittal rotational axes and how this 'may' be part of the missing link between the 2 explanations.
    For example, if the axis is more anteriorly\distally located than 'normal', this will cause an increased plantar flexory moment at initial strike. This could normally be attenuated by the midtarsal joint to allow the COM to progress as the ankle joints ROM has already been used (Not sure about this but I assuming a faster and larger plantar flexion moment of the joint may cause this).
    In a stiffer foot, the Mtjt may be unable to do this leading to a more transverse ROM style of compensation (association between the cavoid foot and cuboid syndrome?) - could this then lead to a laterally deviated StJt axis? (Opposite to the alternative causing a medially deviated axis)

    The thought pattern behind this is that I have often seen both medially and laterally deviated StJt axis move back the 'right way, when appropriate therapies have been applied i.e. the stresses responsible for over loading of the ligaments etc being reduced.

    I would appreciate any comments re this approach as it has worked well for me in practice and fills my theoretically 'missing link' between the SALRE and Sagital plane theories.


    Last edited: May 6, 2008
  17. Dieter Fellner

    Dieter Fellner Well-Known Member

    Hi Steve,

    As the originator of this post I feel obliged to respond to your questions.

    Firstly, please note the patient attended September 2005. After the provisional lateral wedges he then failed to return for a follow up in spite of sending out a reminder. And since this is socialized healthcare, if a patient fails to return the inevitable conclusion is they got better or simply disinterested.

    Over and above of the information I provided in the original post, I have no additional information about the surgical history - the surgery was done by the local orthopaedic surgeon who got nowhere with this patient and referred him to me. I recall (? - apologies, this is a lame response I know, but I am away from my desk on 'extended [cruelly enforced] leave') writing to the orthopaedic colleague to ask to have the operation report, sadly I got no reply.

    My case load is not comparable to that of Kevin's busy clinic; this type of foot complaint is a rare but very interesting finding; running a surgical centre, sadly most biomechanical cases have to be triaged out by the Podiatrists.

    Kevin, I am interested to know if (and please excuse my ignorance if this has been discussed before) the evaluation of the deviated STJ axis stands the intra- and inter observer reliability tests ? On the face of it drawing some felt pen marks on the patient's foot looks awfully subjective, though undoubtedly a skill that could be acquired, but still reminiscent of the heel bisection line, and similar foot drawings, which researchers in the late 80's and then 90's were keen to point out, did not pass statistical mustar? The practical evaluation, i.e. looking at the 3 planar motion during STJ motion can provide a clue, of course, but again, hard to quantify or ratify i.e. how can we be sure I see what you see. Also, have we any studies to show if lat. deviated STJ axis confers an 'abnormal' stress on the peroneals? And if so what defines abnormal and under what conditions of use ?
  18. Bruce Williams

    Bruce Williams Well-Known Member


    from my perspective it is not so much whether the STJ is medially or laterally deviated but that the compensation for both problems, in this instance w/ the peroneal tendinosis, is that of pronation. The AJ does not have available ROM as you stated and the MTJ must compensate for this as much as it can. The medial column will suffer due to the MTJ compensation and DFion of the 1st ray will ensue and this, along with the loss of AJ ROM will cause inhibition of the Peroneals.

    As in PTTD, the tendinitis will eventually become a tendinosis and initial strength will degrade into weakness. To eliminate the pain and activate the tendon again you can address the MTJ adn 1st ray problem by utilizing a valgus FF post. You must also address teh AJ with manipulation and or a heel lift as needed. I see this combination as the primary problem, much as I would in treating Plantar Fasciosis and other "medial STJ axis" problems and leads to your comment above in the 3rd paragraph.

    The problem I am seeing with the verbage of "hypertonicity" is that it is largely up to individual interpretation from differing sources. Many sources see that as being the same as spasticity. Kinesiologists seem to agree accept to say that the tendon will act strong untill it is muscularly tested adn then it is weak. That is exacly the way I see the problem.

    Regarding Dr. Kirby's RF picture w/ the left foot showing more Varus in the affected heel, I would see this as the antagonist PT tendon working against an ineffective PL tendon adn causing the positioning shown.

    I do not see this problem as over activation of the peroneals in a high arched foot, but only as a compensation to a foot that is pronating too long and unable to pivot at the AJ and MPJ's as a result.

    You made excellent points above, adn I do not know if I addressed them adequately or not. I hope so.
    Have a great day!
  19. drsarbes

    drsarbes Well-Known Member

    Hi Dieter:
    I appreciate your situation.

    Since this was posted in the Surgical Forum, I was interested in the original procedure. This would shine some light on his underlying etiology.

    If in fact he had a linear tear of the PL, I have never heard of performing a repair along with a tendon lengthening. It is rather common to have a tear of only one peroneal, but I have a suspicion that your patient was suffering from chronic tenosynovits secondary to rear foot cavus deformity.
    If this was the case, you can debride these all you want and it will not alleviate the symptoms for long.

    If he had an isolated tear with secondary synovits, he would be better by now.

    Given the information you offered, I would not assume the MRI was accurate in Dx peroneal tears.. Often these are tears very difficult to see. For instance, I just repaired a PL two weeks ago - these were the most "beautiful" and classic tears one could hope to see, however, her pre-op MRI was inconclusive.
    I'll upload the picture when I get a chance.

  20. Dieter Fellner

    Dieter Fellner Well-Known Member


    Thank you, I will look forward to seeing the picture.

    I am in agreement with your ideas about his original diagnosis. Alas, I was unable to follow up. As for the orthopaedic surgical treatment planning : I too thought it odd, but hey ....

    With thanks

  21. drsarbes

    drsarbes Well-Known Member

    Here are the pictures. Hopefully I'm uploading correctly, I'm a virgin at this.

    Attached Files:

  22. deco

    deco Active Member

    Hi Steve,

    Nice Pics,

  23. Dieter Fellner

    Dieter Fellner Well-Known Member


    Excellent pictorial illustration of this condition. Thanks !
  24. Steve:

    These are beautiful surgical photos that very nicely illustrate the longitudinal split in the peroneus longus tendon and your surgical technique. Thank you very much for providing them for all of us to learn from.

    Now, if you could post the MRI images to correlate with the surgical photos, to show the limitations of MRI scans, this would truly be one of the best threads on Podiatry Arena and could be used as a teaching case for thousands of other podiatrists. Bravo, Steve, very nicely done!! I am very impressed!
  25. drsarbes

    drsarbes Well-Known Member

    Hi Kevin:
    Thank you for the compliment.
    I have this patient's MRIs on film, not CD. I think I can try to just photograph a few slices and upload them. Hopefully the quality will be good. Give me a couple of days.


    BTW: I love having the RNs take photos intraoperatively for two reasons. I always give a copy to the patient to show their pathology and what was done, and I keep the other copy in the chart. This really helps to refresh my memory when a patient comes in for check ups.
  26. Steve:

    I made my own darkroom in high school and taught a black and white photography/processing class at UC Davis during my undergraduate days. I am somewhat of a camera hound and photography enthusiast. The images of the tendon split is excellent.....the best I have ever seen. Tell your nurses that they do fine work!
  27. Dieter:

    Sorry for getting back to you so late. You have very good questions.

    I have never had the opportunity to perform intra- and inter-observer reliability tests of my palpation technique for determining subtalar joint (STJ) axis location (Kirby KA: Methods for determination of positional variations in the subtalar joint axis. JAPMA, 77: 228-234, 1987). I am attaching the original paper below so that you can review the technique. It is a relatively difficult technique to master, with some people able to do it better than others. It took me probably 2-3 months of trial and error before I could confidently repeat it myself while I was developing the technique during my Biomechanics Fellowship in 1984-85. Recent cadaver experiments from a few years ago that I did with the biomechanists at the Penn State Biomechanics Lab showed that the palpation technique is within a few mms of being accurate but does have error associated with it so it is an approximation of the plantar representation of the STJ axis. We are currently researching newer ways to determine the STJ axis in live subjects that don't involve drilling into the talus (Lewis GS, Kirby KA, Piazza SJ: A motion-based method for location of the subtalar joint axis assessed in cadaver specimens. Presented at 10th Anniversary Meeting of Gait and Clinical Movement Analysis Society in Portland, Oregon. April 7, 2005; Lewis GS, Kirby KA, Piazza SJ: Determination of subtalar joint axis location by restriction of talocrural joint motion. Gait and Posture. 25:63-69, 2007; Lewis GS, Cohen TL, Seisler AR, Kirby KA, Sheehan FT, Piazza SJ: In vivo tests of an Improved method for functional location of the subtalar joint axis. Submitted to J Biomechanics, November 2007).

    Probably the best way to determine STJ axis spatial location in the weightbearing foot is to palpate for the talar head and assume that the STJ axis pierces anteriorly through the central aspect of the dorsal neck of the talus and posteriorly through the lateral-superior quadrant of the posterior calcaneus. That is the position that Dr. Spooner and I found while using our Subtalar Joint Axis Locator on multiple subjects (Spooner SK, Kirby KA: The subtalar joint axis locator: A preliminary report. JAPMA, 96:212-219, 2006). This is the same position on the talus that other researchers have found to be the anterior exit point of the STJ axis.

    Using three dimensional (3D) motion of the foot can be used to also approximate STJ spatial location however you should read the end of my attached paper from 21 years ago to see how I think one should best evaluate this 3D motion in the non-weightbearing examination. I believe I can determine the approximate STJ axis location of a subjects while blindfolded by just holding onto the patient's 4th and 5th metatarsals with one hand and their tibia with the other hand using the "range of motion" technique described in my 1987 paper. I'm sure that other individuals will be upset with me making that claim. Such is my lot in life.:butcher:

    We have no studies that the laterally deviated STJ axis subjects have any more stress through their peroneals than subjects with normal STJ axis location. This is based on theory, biomechanical modelling and my 20+ years of clinical observation of thousands of patients. Here is a brief theoretical scenario that, I believe, will eventually proven to be fact.

    Here is what we know to be fact from biomechanical modelling:

    1. A laterally deviated STJ axis will cause increased external STJ supination moment from ground reaction force (GRF).
    2. In order to maintain the forefoot plantigrade and prevent maximum supination of the STJ, increased internal STJ pronation moment must be present in subjects that have a laterally deviated STJ axis.

    We also know from experimental study that the only two extrinsic muscles of the foot that can cause significant STJ pronation moment are the peroneus longus and brevis. These muscles must, therefore, be the source of the internal STJ pronation moment unless the STJ pronation moment is coming from internal hip joint rotation moment (unlikely).

    From my clinical observation, many individuals with laterally deviated STJ axes will have tonically active peroneal muscles during relaxed bipedal stance that, when asked to relax their peroneal muscles, will supinate their STJ until the medial forefoot is no longer resting on the ground or they will maximally supinate their STJ. I have seen this at least a hundred times before. This is not caused by posterior tibial muscle contraction, as others seem to believe, but is rather caused by GRF acting on a laterally deviated STJ axis.

    I hypothesize that the resultant increase in peroneal muscle activity along with the shortened peroneal tendon moment arm to the STJ axis in the laterally deviated STJ foot will lead to increased peroneal tendon tensile stress and will therefore lead to increased risk for peroneal tendinopathy. Treatment with orthoses that add external STJ supination moments such as valgus wedged orthoses will make these patients more comfortable nearly instantly, thereby supporting my hypothesis.

    I challenge anyone else on this website or anyone elsewhere within the academic community to provide a better mechanical explanation for the above clinical observations.

    Hope this explains the mechanical nature of peroneal tendinopathy for you. Additionally, I hope some of the others who don't believe what I say above can provide us all with a better theoretical explanation as to why these pathologies occur so commonly in these types of feet.
    Last edited: May 8, 2008
  28. deco

    deco Active Member

    Hi Kevin,

    Would it be possible to see a picture of the Subtalar Joint Axis Locator?


  29. Phil Wells

    Phil Wells Active Member


    Thanks for the reply.
    I must admit that I feel the compensation of the Midtarsal joint is far more important than the STjt axis location in these type of conditions - specifically when I see delayed sagittal plane function at the midstance phase of gait. This is based on conjecture on why my ffos seemed to work by the COP acceleration rather than purely pronation/supination forces.
    However the rotational equilibrium methodology is extremely important is explaining forces resulting in tissue stress - at all joints and not just the StJt.


    This does not mean that I discount SALRE, rather it is part of a much bigger picture
  30. Bruce Williams

    Bruce Williams Well-Known Member


    If increased peroneal activity, which you have never proven , "We have no studies that the laterally deviated STJ axis subjects have any more stress through their peroneals than subjects with normal STJ axis location." is the primary cause of this tendinosis, then explain to us why the primary orthosis treatment method that you utilize effects the peroneals only after their ability to fire is turned off?

    You state earlier that you primarily utilize a FF valgus posting in these cases. I agree that this is a good treatment method, though I will also utilize a 1st ray c/o / kinetic wedge 1st, then the valgus wedge at the FF, then a digital FF wedge ( a la cluffy wedging).These all help to add supination moment to the STJ as the foot moves into late midstance and propulsion.

    AT this point in gait though, the peroneals are no longer firing! Wouldn't it be more prudent to decrease the need for the peroneals to fire by laterally wedging the RF post in these patients? I will occasionally, but as you stated this doesn't work as well as the FF posting.

    As I stated before, the peroneals primary function is to DF the 1st ray to allow smooth transition from early to late midstance. In late midstance or terminal contact period, the plantar fascia will take over as the mpj's extend and maintain the supination moment arm that you rightfully say is necessary at this point.

    The peoneals will continue to provide this function thru late midstance if the AJ has available rom, whereby the fibula will move superiorly causing the peroneals to remain taut as the terminal contact phase progresses to full propulsion. This peroneal function is non-electrical at this point, the muscle activation is sht down.
    It cannot fire and does not as the joint positioning does all the work necessary.

    So, why would the peroneals potentially become over activated, but functionally weak, as they are in this form of tendinosis?

    If the AJ loses available DFion ROM then either the heel lifts off very quickly or it has a delayed lift off due to MTJ compensation. Early heel off is not a problem b/c the peroneals will continue to be positionally active and since they don't have to fire as long will be less prone to inflammation and then tendinosis.

    In the feet where the AJ does lose DFion rom and the MTJ compensates you will start to have a serious problem. In these feet the heel will not terminate contact period as quickly. Howard and I have thousands of F/T curves to confirm this process. As the contact period continues, longer than it should, this may allow the peroneals to continue to electrically fire since they think they can. That delay in heel off in late midstance is most likely the cause of all three primary tendinoses in the foot / ankle, ie PTTD, Achilles and Peroneal tendinoses!

    This problem is not axial at all except to predispose one muscle group, the peroneals, into over actvation, but only after that muscle group loses positional activation in late midstance!

    If your hypothesis were true Kevin, then you would treat all of these with a RF valgus wedging with a significantly high success rate. You have said yourself many times that you do not treat that way most of the time. You are not decreasing the normal electrical activation period of the peroneals by your use of FF valgus wedging, only decreasing the prolonged supposed electrical activation period of the peroneals by assistng the plantar fascia to take over the necessary supination moment that the foot was unable to do itself.

    Ultimately, foot dysfunction is about the transition from one pivotal period to another. Stoppage, or delay, of an any of these transitions will lead to dysfunction. Elimination of these delays leads to elimination of the sypmtomatology. Axial theories most definitely lend to the explanation of the physics of foot function. But, positioning alone will not automatically be the cause of any one foot dysfunction provided the foot continues to transition uneventfully from step to step.

  31. Phil Wells

    Phil Wells Active Member


    I have no partisan feelings to a single method - SALRE v's Sagittal plane - but I do feel that your explanation fits what I see clinically.
    I do place a little more emphasis on Stjt axis as it helps to explain the impact of external frontal plane moments when assessing the gait more globally e.g. IT band issues with a lat deviated axis but on the whole I agree with what you are saying.

    Thanks for the input from you and Kevin


  32. Bruce Williams

    Bruce Williams Well-Known Member


    you are most welcome. I appreciate the opportunity to stretch my understanding of what I think I see and how it works within my capacity to interpret it.

    Dont' get me wrong re: axis positioning. It makes a difference without a doubt. I do use a medial heel skive to some degree on the majority of my devices, as well as a midfoot valgus wedging w/ my other sagittal plane prescriptions.

    In patients wtih high arches like the one that started this example I will utilize a RF valgus post if the pateint can tolerate it, but at times I will find that a RF medial post works better.
    I don't understnd the mechanism completely, I assume it is loosely based on proprioception, but many higher arched feet tend to relax their compensations when posted medially to a proper degree.

    Thanks again.
  33. Bruce:

    I don't have a clue what you are talking about here, Bruce. The peroneals are active throughout midstance, which is when both the rearfoot and forefoot have signficant ground reaction force (GRF) acting on them, which is then also when a rearfoot and forefoot valgus wedge would increase the external subtalar joint (STJ) pronation moment. In turn, this increase in external STJ pronation moment would therefore decrease the need for the central nervous system (CNS) to generate an efferent signal for increased peroneal muscle contractile activity to generate an internal STJ pronation moment.

    If you will notice in my orthosis prescription for these patients that I always use a lateral heel skive on these patients which is a "rearfoot valgus wedge". I don't know where you came up with the idea that I only use a forefoot valgus wedge. Please show me where I ever said that I only use a forefoot valgus wedge.

    Further support for STJ Axis Location and Rotational Equilibrium (SALRE) theory of foot function comes from the observation that forefoot valgus wedging is more effective than rearfoot valgus wedging from the simple mechanical fact that the lateral forefoot has a much longer pronation moment arm for GRF to cause a STJ pronation moment than does the lateral rearfoot.

    The peroneals have increased muscular activation for two reasons:

    1. GRF is generating increased magnitudes of STJ supination moment due to the laterally deviated STJ axis so the peroneals need to contract with more force to generate more internal STJ pronation moment.

    2. The pronation moment arm for the peroneals is greatly reduced in a laterally deviated STJ axis so that they must contract with more force to generate a lesser amount of STJ pronation moment due to their decreased STJ pronation moment arm.

    The peroneal muscles may be strong in these individuals when tested in maximum pronation, but may also function relatively weakly due to their reduced STJ pronation moment arm which occurs closer to the STJ neutral position in which they function.

    I don't treat these with just forefoot valgus wedging, Bruce, as you suggest. I use both rearfoot and forefoot valgus wedging. Maybe you are not decreasing the efferent activity of the peroneals with your treatment, but I will bet that I am decreasing the efferent activity to the peroneals with my treatment, which is highly effective.

    This is an interesting theory, Bruce. Do you have any research evidence that supports your hypothesis that "Stoppage, or delay, of any of these transitions will lead to dysfunction. Elimination of these delays leads to elimination of the sypmtomatology"? I know these statements are central to the Sagittal Plane Facilitation Theory and are thrown around many times in these discussions but, to my knowledge, there is no support in the literature for your statements. Please provide references.
  34. Declan:

    Sorry for the delay, very busy week here. Here is a photo of the STJ Axis Locator. I have also attached Dr. Spooner's and my paper on the Locator. Have a nice weekend.
  35. deco

    deco Active Member

    Hi Kevin,

    Thank you for the pictures and the PDF, they are a great help,

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