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Biomechanics V Surgery

Discussion in 'Biomechanics, Sports and Foot orthoses' started by bob, Jul 9, 2010.

  1. bob

    bob Active Member

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    In a separate thread a discussion arose that's more eloquently put than I could by Kevin's post below.

    Kevin Kirby wrote:
    "Why is it that the podiatrists who have the least understanding of the complex biomechanics of the foot are also often the ones doing more surgery when compared to the podiatrists who understand biomechanics the most and are doing more foot orthoses than foot surgery? Shouldn't the ones (i.e. surgeons) that risk permanent harm to their patients by doing foot surgery be also the ones who have a much better understanding of the complex biomechanics of the mechanical appendage that they are making permanent structural changes to? Something doesn't seem quite right to me when the podiatrists or orthopedic surgeons who are most ignorant in biomechanics are often also the ones doing the most foot surgery.

    Anyone want to propose an answer to this perplexing observation?
    IMO, and with exception of everyone reading this thread because by definition these are the surgeons who have a desire to constantly improve themselves..."

    Robert Issacs replied:
    "Because Biomechanics is the "road less traveled." It requires ceasless study and re-examination of ones self and yet the more one learns, the less one realises one knows. In many senses it demands that one constant re-invent ones knowledge base. Surgery, by contrast, requires bigger initially investment in technical and manual skill but once that is learned one can coast happily, enjoying the prestige and earnings with no more study than one desires.

    A surgeon may feel they have "arrived" when they get their consultant status (in the UK at least). A biomechanist, perhaps, never truly "arrives".

    The two are different and appeal to different Id's within us.

    And dare I say because it is easier to cut a foot open than to try to understand how it works?

    Or, if you want a bumper sticker, surgery is for sadists, biomechanics is for masochists and the surgeons who like biomechanics (ie you if you're reading this) are by inference Sado-masochists.

    I love biomechanics. Love it. I've never had the slightest urge to upgrade to be a podiatric surgeon. I know surgeons who've no understanding of biomechanics and, more, desire none.

    Perhaps that is not how it SHOULD be but I think that is how it IS."

    OK. Robert, I think your view on practitioners specialising in biomechanics versus those in surgery is based on your life as a specialist in biomechanics. A pretty simple statement to make and it seems obvious, but I think it's important. I am not a specialist in biomechanics so I don't know how much self-flagellation and re-examination you guys do, but if I need an opinion on conservative care of a patient I trust that you guys will come up with the goods. However, I can speak as a consultant who's 'arrived' as it were in surgery in the UK. Unfortunately, I didn't arrive. I think I must have fell asleep at my stop so I'm waiting for the end of the line to get the train home.

    Surgeons in the UK (I will wait for my colleagues in the US to comment on their situation as they will have a far greater understanding about it than me) have to keep abreast of developments within surgery, medicine, etc... just like anyone working at a senior level in any discipline does. A simple example is the NICE recommendations on use of the Hyprocure, but there are many, many more examples. From the outside looking in, it may appear that we are just coasting along, resting on our laurels and all that (and to a degree, all practitioners across all disciplines will be guilty of this) but it sadly isn't really true. Trust me, it's not that easy to cut a foot open.

    My experience of podiatric surgeons in the UK is varied. I believe we all have a grasp of how (we think) the foot works and to varying degrees we will respect this when offering surgery (or not!). There is and probably always will be an element of 'straightening the deformity' as this is a basic and fundamental principle of anatomic reduction of deformity associated with painful pathology/ presenting complaints. There have been a variety of research articles and options for quantifying outcomes of foot surgery and none of them really give the full picture. If a patient comes to see me with a bunion, they may complain that it rubs on their shoe and they want it straightening. I might see tibial sesamoid positions, intermetatarsal angles, etc..., but the patient owns the bunion and they want it straight and not rubbing on their shoe. So I do my surgery and it's nice and straight, doesn't hurt, they can fit whatever shoes on, everybody's happy. But did I restore normal function to the joint? I don't know. I must admit that I have a general appreciation of how a 1st MTPJ works, but I would not claim this to be complete. This joint accounts for approx 50% of my surgical workload. You biomechanics specialists might have a better understanding of how the joint works than I do? This is why I wouldn't agree with you're 'upgrade' comment - it's just a 'different' path.

    The fact that we chose different paths may go some way towards answering part of Kevin's original question. For many reasons, the profession in the UK is fragmented into specialisms. A major factor in this is the way departments deliver service within the NHS. Another is training in surgery as it is serves to isolate UK podiatric surgeons. Along with this, there appears to be a level of intra-professional envy/ ignorance in podiatry in the UK. I have heard colleagues dismissing biomechanics and orthotics based on the fact that they are operating on all the 'failures' from their local biomechanics department (the sad thing is their local biomechanics department probably thinks exactly the same about them). This is not just isolated to our specialisms. I have had some very bizarre and negative reactions from some of my old classmates who are working in routine private practice when they find out I went down the surgery route. I believe that fragmentation of the profession in the UK perpetuates these ridiculous attitudes. I do not believe any section of podiatry is greater or lesser than the next (most days :D).

    My original training in biomechanics feels outdated. It was very much Root, Orien and Weed. Terminology changes and approaches to assessment and treatment develop. Reading journals and some of the threads on here helps to keep up to date with some of this. I hope that outcomes improve as these changes occur, but I don't really know if they do. Does the local surgeon who has been rattling out chevron osteotomies for bunions for the last 20 years have better results than me even though he's just ploughed on with it and I've stopped and looked around every now and then? I don't know is my honest answer. What I do know is that surgery is not perfect. It's this that makes me want to learn more and I'm hopeful that that will improve outcomes - whether the patient ends up with and orthotic or a hyprocure.

    Oh, and by the way, I'm not a sado-masochist, you can't prove that I am, it was probably someone who looked like me, and it's not until I've 'arrived' that I would be about to seek 'professional' advice on sado-masochism :D
  2. I beleive we must at least in countries outside of the US, also consider the orthopeadic surgeons.

    As my understanding goes one of the main things that seperated a Podiatric surgeon and an orthopeadic was the amount of foot biomechanical knowledge - am I wrong with this ?

    That´s why I always find in strange/sad/funny that there is debate in the US about the need to have biomechancial knowledge taught at the same levels as today, I would expect the results of Surg to be improved with a greater level of Knowledge.

    In Australia, Sweden and New Zealand, the countries where I have worked and studied ( I get around) I would ´guess 90% of internal foot surgury is done by orthopeadic surgeons. I had "biomechanical arguments" with more than one ( my nature). I´ve offered to send over journal papers to one explaining there is no transverse metatarsal arch ( I go on a bit about it), but the major problem is most and I say most in my personal knowledge are not even going to listen to me, whether they think I might be right or wrong.

    So if there is an orthopeadic surgeon ready this maybe they could explain to us the level of university training you had in foot biomechanics and what is your understanding of current theories ?

    I guess I won´t get an answer, but time will tell.

    I could go on but better go do some lab work.
  3. bob

    bob Active Member

    Hello Michael,

    I think you are right when you say that podiatric surgeons are supposed to have a greater knowledge of foot function than orthopaedic surgeons, but this will vary vastly from surgeon to surgeon. Some orthopaedic trainees have lectures (usually a single lecture or a short series) from university-based researchers in biomechanics and may go on to contribute to research in the area. I see you mentioned talking to a local orthopaedic person in another thread that did some bone pin study - so their interest in foot biomechanics is probably greater than the vast majority of their colleagues (and probably many of my colleagues). Generally, I would say that podiatric surgeons do consider function and attempt to be 'joint-sparing' where possible, but this is only based on local personal experience. Again, it's hard to generalise as the sort of orthopod who will read this board (nevermind leave a comment) will probably be more interested in foot function than many of their colleagues.

    Have a good day.
  4. tonyw

    tonyw Member

    It really does sadden me when I read this nonsense about how one thing is better than another and how its easy to cut open a foot. (of course that can only be stated by someone who does not). The reallity is that biomechanics is a fudemental part of surgery, although surgeons do not bang on about it, and in my opinion, the ones who dis surgery in favour of biomechanics probably have a major chip on their shoulder and somehow feel a little inadequate which is a shame.

    A true specialist in the field of Podiatry will consider all options and in all cases discuss conservative options. I myself practice biomechanics and work closely with biomechanics specialists in the NHS to ensure best care. However you can't change the structure of hallux valgus with orthotics or manipulation, so for those patients who want a straight foot, surgery may be the only way. What is important is to consider the mechanics first so one can better advise the patient regarding possible consequences of surgery. If I am honest the more surgery I do the less I do. Thats experience! I still do as much surgery but I am far more selective.

    Why can't we just work together as a profession and be proud of the full range of services we can offer, its bad enough fighting with orthopods let alone with ourselves.

    Tony Wilkinson
    Dean: Faculty of Podiatric Surgery
  5. Tony a very good post except this

    Sounds like your looking down from a high tower.

    The problem is that a some surgeons do not follow the mechancial (orthotics) then surgury options or this is the only answer for you, you must have surgery. I hear everyday "why was I not given the conservative treatment option by the surgeon, they told me there was only surgery for treatment". It does get to you after awhile, especially with a good treatment approach the patient gets better without surgery.

    As an aside if you look to the US there is quite alot of discuusion about the amount of biomechanics taught at school.

    Which I think is not a great discussion to be having, the greater the biomechancial knowledge, must lead to better surgical based discussions.
  6. tonyw

    tonyw Member

    No I am not looking down from a high tower at all, quite the opposite in fact, it was Bobs thread that led to that statement " a surgeon has arrived, and a biomechanist may never arrive" his quote not mine!

    In some cases surgery is what the patients want and the classic is hallux valgus which is also the bread and butter of Podiatric surgery. I suspect that the patients who say why wasn't cons therapy offered first are the ones that have not worked out! Otherwise why would a satisfied surgery patient be suggesting that? You cannot and MUST not judge Surgeons in this way. I have a small number of patients who when it is not all good post op say, I wish I had not done that and tried more conservative theray. Quite often they just forget that it was they themselve who limited the conservative options. Of course it is harder not to operate than to simply stick the knife in, only to regret it 6 months later. A good surgeon knows when to operate and when not to and that is the skill of surgery!

    What I don't get about biomechanics is the fact that all the time spent working out whats going on, gait scans etc leads to an off the shelf insole with some bits stuck on. Hardley precision. The same goes for surgery, you can measure as much as you like but in reality there are only so many ways you can cut bone and in the end you just shove it to a point that looks right. Niether an accurate science.
    What we hope is that the patient gets better and thanks you for it. The worst thing that can happen in most biomechanics cases is the insole does not work and you throw it in the bin. With surgery the risks are much higher.

    Tony W
  7. bob

    bob Active Member

    I'm sure Tony can speak for himself, but lets not start reading too much into people's intonation on an internet forum hey guys? Regardless of specialism, there will be elements that do indeed have a very insular outlook on treating a patient. Some surgeons may see surgery as the only answer and feel that orthotics are a waste of time based on experience of seeing failed orthotics cases all the time. Some biomechanics specialists will see surgery as butchery based on picking up surgical complications. Surely we are all professional enough to understand that all our successful cases are out there wandering about forgetting our names and the fact that they have had any treatment? We will only see the small percentage of each other's work that is not entirely successful.

    What we have also got to consider is that the patient's view that they report to us regarding their previous treatment will be biased by a variety of factors - especially considering they didn't have a good result (or they wouldn't be sat in front of us asking for help). We can all tell horror stories, but I feel Kevin's original question will remain elusive and the thread will deviate off on a tangent.

    I'm glad to see Tony echoing my sentiment of fragmentation of the profession being a factor in the gap between biomechanics and surgery and am encouraged by his closing line. As far as Michael's last line goes - I don't know? Would it benefit a surgeon to have a greater understanding of biomechanics? (I think so, but I really don't know) And who says they don't? We may use different terminology to descibe the same things - treatment and assessment, but do we get the same result? And can we improve all our results by working together? I hope so. :drinks
  8. tonyw

    tonyw Member

    Well said bob

    Why don't you and Weber come and see me sometime. Whe can look at ways of better integration.

  9. Ok we can let it go now, and as Bob suggests keep it on Topic.

    So I´ll as a question to 2 pod surgeons. Should greater biomechancial knowledge lead to less Surgery ?
  10. bob

    bob Active Member

    I think that's a great idea, but maybe it would be best for representatitives from all specialisms within podiatry to meet and discuss integration and how it could and should impact on training? I suppose this is already done via SCP though? I guess we're all busy people, but it'd be good to have some sort of open forum where we could meet and discuss ideas? Maybe a conference?

    I think it may be more difficult for Michael as he's based in Sweden, but I'm sure he would be very welcome. Also, if he's interested in people visiting Sweden that may be good? Regardless of venue, I'm sure a face to face meeting would help avoid some of the difficulties encountered when discussing issues over the internet - the best part about it is the convenience, but I'd like to let everyone know that I hope any of my remarks in this thread do not come across as though I am being sarcastic, supercilious or in any way negative. I really do think we should all be working together towards a common goal. :drinks
  11. tonyw

    tonyw Member

    No is the answer.

    Better understanding of biomechanics leads to a better range of treatment options. Not less surgery in itself. Remember you cannot perform surgery without some knowledge of mechanics. Some will have more theoretical knowledge thn others

    Biomechanics is fundemental and is as important in our treatment options as surgery. The key is to ask the following questions with all patients.

    1. What is the patients goal? -Compliance is a major factor
    2. Could the condition be treated effectively by conservative means -less is more
    3. has the patient been made aware of all options including risks and benefits of each modality - Medico-legal

    in the end the patients will have their own aims and objectives and will make an informed choice.

    Tony Wilkinson
  12. It is a great idea and distance from my side maybe a problem, I will be in London next year for some CPD stuff unless Icelandic Volcaneos spew forth again. I´m sure that there are folks closer that may have lots to add to the discussion.
  13. Ok another question if I may, Does greater knowledge of Biomechancis lead to better post op results ?
  14. tonyw

    tonyw Member

    Again I think not.

    Lets take flat foot TPD

    What are the options available-limited!

    Frontal plane dominance MDCO- shove calc medially 10mm OR AS CLOSE AS
    Equinus- Lengthen TA or Gastroc
    Tendon Tib post- augment it FDL, or other

    alternatives (1) Evans in transverse dominence
    (2) Arthroerisis (hyprocure) in flexible- Caution
    (3) Fusion in rigid end stage - that will really suff the mechanis but is great for pain

    So it does not matter how much you measure mechanics the options are still limited at the moment. I just can't see how we could transfer intricate measurments into surgery. unless we have some cad cam robotic surgery in the future. In the hands of a human no way.

  15. I study biomechanics and I've just come, I mean arrived at this thread. hello Tony, you said:
    I think a better question might be: if the USA continue to turn away from biomechanics within their studies in favour of surgery, will the evolution of surgical procedures stagnate as a consequence? Moreover, will the limitation of biomechanical knowledge within these podiatrists limit the tools in their arsenal? If all you've got is hammer, everything looks like a nail.

    I should like to think that improvements in our understanding of the biomechanical function of the foot should lead to both improved conservative care and improved surgical care.

    Now here's the crux, lets say I'm multi-talented: I'm a podiatrist who's arrived at biomechanics and I'm also a surgeon. I develop an new surgical procedure for bunions that is frankly the best thing since me. My surgical colleagues can learn this procedure and carry it out successfully without having to learn the biomechanics behind it. Similarly, me being multi-talented as I am, I can develop a new pre-fab orthotic for bunions which does correct them. All of my colleagues can implement this device in patients with bunions (as long as they can spot a bunion) without understanding the mechanics of the device.
  16. Not at all what I was expecting ....

    Alternative 2 Hyprocure brings us back to why this discussion stated in the 1st place. Biomechanical treatment post Hyprocure

    I would have assumed the greater the biomechical knowledge would lead to much better discission making and better Post op results. Considering stuff like to postion of the STJ axis and the effect of the new internal and external moments post surgery would be very important.
  17. bob

    bob Active Member

    That's an interesting point Simon. It is possible that certain surgical procedures that are out there already have been developed through trial and error, but remain mechanically sound. Take the scarf osteotomy for hallux valgus as an example. Thinking about the mechanics, ground reaction force will be predominantly perpendicular to the main cut compressing the fragments and improving healing times. Contrast this with a Mitchell osteotomy where ground reaction force would have a vector that is predominantly parallel to the cut towards propulsion. Perhaps this gives us better post op results? Perhaps if surgeons had a more complete understanding of mechanics and physics, we could improve our surgical techniques quicker than trial and error does? We might not need to know intricacies of theory, but a general understanding and closer working relationship with our collegues in biomechanics would hopefully lead to better results?

    Michael - Perhaps an interesting project would be to check subtalar joint axis location pre and post arthroeresis insertion? As Kevin (and possibly Eric) said on the other thread, these devices serve to block motion into pronation at some point in the total range, but I don't know if they affect the location of the axis of motion? I presume it would.

    I think Tony makes an interesting point about the hands of a human. I suspect my sagittal saw is more like an artists paintbrush than an engineer's pencil (or computer program, whatever - I hope you can see my point). Although, how accurate are orthotics? I have seen CADCAM orthotics, but I wonder how these deform under load and how they alter shape when placed in a shoe? I guess there are many factors that affect the transfer of force from the floor to the bones of the foot - sole of the shoe, orthotic and its material, material properties of the foot's soft tissue, etc... Regardless of our choice of treatment, there is probably less precision than we would like. But does that mean that we should not try to improve on it?
    Last edited: Jul 9, 2010
  18. Go back a step Bob, what defines the position of the axis? Then we need to think in 4-dimensions, how does the bolt change the position of the axis and when?
  19. bob

    bob Active Member

    The position of the axis - this would be defined by the relative motion of the 2 bones concerned? So, would the arthroeresis actually change the average spatial orientation of the axes, or would the patient have a normal progression of the axes of these two bones until the arthroeresis stops their motion (thus stopping the motion of the axis) ? :confused:
  20. I'm glad that my question has stimulated such an interesting discussion...and a discussion that is certainly very important for the international podiatry profession.

    For you surgeons out there, and contrary to what many believe about me and my practice, I do have a busy surgical practice. I have already performed five surgeries this week and have another one scheduled for Monday morning at my local surgery center. Therefore, I believe I can see both sides of the argument quite clearly.

    One of the observations I have made over the last quarter century of practice is that there are many podiatric surgeons that seem much too knife-happy, that seem know little about the finer aspects of appropriate conservative care methods, and always seem to be looking for ways to do surgery on their patients rather than looking for better conservative methods of treatment that will allow them not to have to do surgery on their patients. I believe this is the result of them either not knowing how to perform better conservative care treatments for their patients or not wanting to learn or possibly perform these techniques that will prevent them from doing more surgery, since surgery may boost not only their own ego but also their income.

    I believe the best podiatric surgeons are also the ones that are devoted to understanding the biomechanics of their surgeries as completely as possible. Fortunately, I am also good friends with some very respected podiatric surgeons that are also very interested and proficient in biomechanics and that I consider to be the models for the perfect podiatric surgeon. Individuals such as Drs. Don Green, Rich Bouche and Jeff Christensen could teach classes either on biomechanics or surgery and distinguish themselves from other podiatric surgeons by carefully considering the biomechanical implications of their planned surgeries for their patients.

    Unfortunately, with the reduction in biomechanics training and increase in surgical training here in the United States, we are moving, as a profession, more towards becoming the equivalent of what many might consider as limited license orthopedic surgeons, with less understanding of the complex biomechanics of the foot and lower extremity, less emphasis on foot orthosis and shoe therapeutic options, and more emphasis on surgical equipment, surgical techniques and surgical treatment of foot pathologies. I am determined to not let this disastrous event happen to my profession, if I have any choice in the matter.

    I encourage further discussion on this subject since I believe that our striving toward a full integration of biomechanical principals into the surgical curriculum of the podiatric medical colleges and surgical residencies, into podiatric seminars and into podiatric surgical textbooks, a full biomechanical-surgical integration within the podiatric community, will allow podiatrists to remain at the forefront of the medical profession for both the conservative and surgical treatment of foot and ankle pathologies.
  21. MR NAKE

    MR NAKE Active Member

    Sounds like chicken and egg to me. Let Biomechanics deal with what it can, and surgery deal with its own, both are equally rewarding specialities. Both practitioners (Biomechanical specialist/surgeons) are equally valuable according to@tony. The bonus will certainly be, if we encourage the "multi-talent" aproach to this saga according to@Spooner, then we will have ultimate super clinicians!.....hopefully the debate will lay to rest,,,,,,, which part of the body is the most important above all others then?????
  22. - Forces define the position of axis.

    -The stent will effect/change the position of the axis during pronation, when the compression froce between the talus-stent and calcaneous are the same or greater than the pronation forces.
  23. Not only forces. Remember the STJ is pretty constrained by the ligamentous structures. The shape of the articular surfaces will be important. So does the surgery change the shape of the articular surfaces?
  24. Bob? where did you go ?

    It must, at the point where the stent comes into contact there would be increase in pressure and I guess friction forces as well . ?
  25. The whole point of the surgery is that will limit the medial excursion of the axis during dynamic function and in static stance. Now if it limits it to within normal limits without excessive bolt on bone compression that's great. If too much compression- not so good. How is this worked out pre-operatively?
  26. Mr. Nake:

    You miss my point. Surgery is internal biomechanics. Foot orthosis therapy and shoe therapy is external biomechanics. Biomechanics and surgery should not be considered as two separate specialties within our profession. Foot surgery should be considered a subspecialty within the broader specialty of foot biomechanics.
  27. :good:

    Dead on the money.

    There is a tendancy to confuse "biomechanics" with "orthoses". They are different. Biomechanics is the study of mechanical principles in living tissues. As such it must surely be integral to both surgery and orthotics.

    However, we have drifted somewhat. The initial question was not which is better, nor anything to do with vs. It was:-
    And I think the answer is contained in this thread.

    These two posts highlight the answer to the question. Why are podiatrists who have little understanding of biomechanics doing surgery? Because they do not see that biomechanics has anything to offer surgery.

    Perhaps this is because of the fallacious belief that Biomechanics is synonomous with orthotics. If people think this then they will naturally have little interest in studying biomechanics as they do not see its relevance to surgery.

    What do intricate measurements have to do with biomechanics?

    However, Tony made one point that I would passionatly agree with,

    I offer that the tools to decide when surgery is the best option, and which surgery is the best option, besides things like compliance, bone density, medical history and such, are what biomechanics has to offer surgery. I don't mean 40 year old biomechanics, measured RSCP and angles and such, I mean real biomechanics.

    Case in point, Mikes Hyprocure patient.
  28. Wow. Friend of yours Kevin?

    Having had time to re read this thread I would like to go back to one of my initial comments and some of the reactions too it.

    This obviously caused a few people to take umbrage and for this I apologise. I expressed myself poorly. That's what you get for posting when one should be sleeping.

    The point I was trying to opine was not that it is easy to cut a foot open, far from it. I have great respect for anyone with the courage to try to knock down and rebuild somebodies framework. I'm certain that honing these skills can be the study of a lifetime.

    What I was trying to communicate was that however technically difficult surgery may be, one has a pretty good idea if a surgery is "good". No screws coming loose or non unions, that style of thing.

    Trying to understand how it works on the other hand, is considerably more esoteric.

    Different types of skill.

    Take mikes othopods with their transverse met arch. Easier to believe that than to look into it in more detail and try to understand a 4 dimensional dynamic windlass. That is no reflection on their level of skill, but they have taken the "easy" interpretation rather than the harder, truer one.

    Case in point. I get about half a dozen referrals a week from the local surgery team, generally verbal. Probably the most common phrase is that they need "orthotics to stop the bunions growing back / getting worse"

    now that's a promise I can't keep. It's a bit more complex than an orthotic stopping a bunion. It's a whole different mindset. A surgeon can say with confidence " what I do WILL straighten your bunion" an honest orthotist can rarely be so certain.
  29. I also think that Simons question should not be missed as well.

    Hopefully Bob, Tony or and DPM´s such as Steve may answer this

  30. bob

    bob Active Member

    Hello Michael,

    Apologies for my absence - I had to do a bit of surgery ;)

    I thought that forces drive the motion and that the position of the axis would be defined by the relative motion of the two bones of interest? As Simon has said, the pattern of motion (and therefore position of the axis) will also be governed by shape of articular surfaces, surrounding ligaments and timing and magnitude of contraction of the relative muscles that pass tendons that exert an effect on the joint of interest?

    I'm unsure whether insertion of a hyprocure would affect any of these structures as it does not change the shape of the articular surfaces, seeks to preserve the surrounding ligaments (although you do cut the interosseous talocalcaneal ligament to facilitate placement of the most narrow section of the arthroeresis into the canalis tarsi) and it shouldn't effect the surrounding muscle action via tendons (if performed in isolation)? My basic understanding of it is that it will block motion into pronation by exerting a reaction force on the two bones surrounding the sinus tarsi as the talus gets to a point as it is moving further into plantarflexion and adduction on top of the calcaneus, which would normally narrow the sinus tarsi.

    To answer Simon's question regarding how a surgeon works out how to work out how much you want to block motion - this is part of your overall work-up to surgery, but the actual choice is made on the table. The kit comes with a series of 'implant sizers'. You make your dissection, insert each sizer and make a decision on the size of implant to use based on a non-weightbearing exam of rearfoot motion (I know this is not ideal and may not truly reflect dynamic motion, but it has given me pretty consistent results in the 10-20 that I have done so far). I guess the hit and hope element of this approach is mainly governed by the design of the implant - if we could design an implant for every individual and manufacture it for that person, it might improve outcomes? I guess one of the guys who has done silicone arthroeresis surgery in the past might be able to comment here as I would have thought that that type of device would conform to the shape of each individual better (although I recognise the different material properties as a large variable).

  31. Out of interest, do you repair the interosseous talocalcaneal ligament once the implant is positioned?

    Regardless, how do determine the amount of pronation to block?

    Bob you added some to your post after I had posted this, but to be honest it still doesn't answer the question. So, you look at non-weightbearing motion, trial some different implants and decide which one is best, based on....?
  32. bob

    bob Active Member

    Good post Kevin,

    I think the title of this thread was probably a mistake. Or perhaps it was a deliberately sensationalist title to provoke debate? Oh well. I agree with you and it's nice to see views of our colleagues in the US being expressed. I feel that terminology is partly to blame for some of the friction within the thread and within our profession. In the UK, the main organised provider of foot health services is the NHS. The NHS podiatry services generally deliver 'podiatric specialisms' as separate services (or at least subsets within their own service). I feel this perpetuates intra-professional division in the UK and encourages podiatrists to pigeonhole biomechanics as being the thing that the people who make insoles do. This is also borne out in the private sector (to a point, although I know there are exceptions) as a natural extension of the NHS divisions and modular approach to delivering podiatry education. I'm not totally denigrating these methods of delivering care or education as I am aware that I am not offering a reasonable alternate, but I don't have time (or inclination) to get sidetracked from the main thrust of this thread and get into that right now.

    In the UK, we all go through the standard podiatry degree that covers conservative care primarily and at length. During the Master's section of training on podiatric surgery, all podiatrists will work in providing some form of conservative care to patients - whether it's clip and chip or orthotics. There really is no escape for a UK aspiring podiatric surgeon :D

    So perhaps we have the advantage in being a more all-round podiatrist? Of course, I really don't know the answer to this, but I hope you get my general point.
  33. bob

    bob Active Member

    Nope, just wait for it to scar-in. :D
  34. bob

    bob Active Member


    I feel we're both making similar points but saying it in a slightly different way - very similar to both of our problems with using the term 'biomechanics' to only describe that thing that those guys who make insoles do. In my experience of podiatric surgeons in the UK, they are all interested in foot function and will describe this in their own terms based on their own experience and training, but they generally do not use the same terminology that you see commonly used by 'biomechanics specialists' (apologies for the ironic moniker) that you commonly see on podiatry arena.

    I have spoken to several colleagues about biomechanics in the past and I feel that some of their prejudice regarding 'biomechanics' stems from dissatisfaction with their training in biomechanics. Like me, it was generally Root Orien and Weed. Now, I am not here to say how rubbish it was (it was pretty interesting really), but I felt there were more questions left unanswered by my training in biomechanics than answered, which left some feeling disillusioned and probably spawned their disinterest.

    I'd like to extend my apologies to Dr Bijak - the title of this thread was posted to provoke debate. I am not here to start fights within our profession. I don't want to sound like a hippy, but I'd really like it if we can use these discussions to improve all of our relations within our profession and help us all move forward.

    No need to apologise, no offence taken. One of the surprising and interesting things about surgery is the infinite amount of variables there are when performing pretty much any operation, from putting knife to skin to throwing the dressing on at the end - and that's the easy part, getting it to heal and work properly is not quite so easy. Your comments regarding 'good' surgery made me giggle, but I think I get your point. There really is quite a lot more to it than that, but we'll move on ;). We all underestimate the amount of skill that goes into each of our jobs.

    I admit I am, have been and probably will be in the future quite flippant and lazy on occasion and refer a patient to my colleagues in biomechanics for 'orthotics' (not to stop bunions getting bigger as that's a different thread altogether) but for whatever reason. We're human, we have good days and bad days - but generally very busy days. I think some of the divide between our two 'specialisms' is based on terminology - as you have said with your orthopod's example. Now that may reflect a poor understanding on their part (transverse arch - wtf?) or as you kindly said, an 'easier' interpretation. This probably comes full circle to my interpretation/ offshoot of Kevin's original question - does this more technically accurate appreciation of foot and ankle biomechanics improve outcomes in foot surgery when compared to a general appreciation of foot function (regardless of terminology)?

    Answer - Er, I dunno! :D
  35. bob

    bob Active Member

    Still having some eversion of the calcaneus relative to the tibia available, but to have reduced this from the original position without the arthroeresis in situ. And checking forefoot to rearfoot relationship, etc.. (results depending on if doing the procedure in isolation). Ultimately, it's an eyeballing exercise that I recognise will be open to the same variability as using a medial rearfoot wedge. I hope this answers your question better. Maybe it would be worth going to see your local podiatric surgeon put one in as it's usually much easier to show these things rather than type them out?
  36. I can see that it's fairly hit or miss. Thanks for you honesty, Bob.
  37. bob

    bob Active Member

    No problem Simon,
    It's like everything we all do - there is a greater element of art than many of us would like to think or admit in the vast majority of all of our interventions. One of my reasons for being interested in biomechanics is I am hopeful that this may help me to improve the 'science' part of my interventions - whether this will improve outcomes is debatable - which is a subtext of some of this thread. :drinks
  38. Another question Bob if I may, If "biomechancis podiatrist" who we shall call Sebastian, spends hours working out a complex forum where with weight bearing xrays , to determine joint space between the talus and calcaneous, through understanding of the position of the STJ axis and force plate findings. It would allow you to determine which size stent to use and how much compression force the stent would be under during gait and a higher understanding of post-op results .

    Do you think surgeons who take the extra exam time to undertake Sebastians assessment ? or would Sebastian told thank you but no thanks.
  39. bob

    bob Active Member

    It would depend on research into the assessment tool and other factors - such as how much ionising radiation does it expose the patient to? And does it improve outcomes in a similar patient group when compared to the sizer approach? And how much does it cost? And does this static examination have any greater relation to dynamics than the existing method?

    If these issues could be explored and answered, I can see no reason for anyone to say no to it. Obviously these are the first questions that pop into my head and I'm sure others can add more.

    Also why shall we call them 'Sebastian' - why not a manly name such as 'Nick' or 'Chuck'? :D
  40. efuller

    efuller MVP

    A story from when I was a student watching a surgery. I'd seen about 20 bunion operations prior to watching this procedure. The surgeon had removed the bump and had the joint open and was getting ready to close the joint capsule and was about to consider how tight to make the capsule for realignment of the toe. He loaded the first ray from planter and dorsiflexed the toe. With attempted dorsiflexion there was a slight movement of the first toe toward the second. The surgeon then cut a small amount of the fibular attachement between the sesamoid and the proximal phalanx. Repeat loading a smaller ammount of the same motion. Cut a little more, repeat. No movement of the first toe toward the second. Then closed it up. The surgeon was telling the residents he was doing this on purpose.

    This happened before I had heard about reverse buckling and long before I understood force vectors. However, this is a perfect example of applying the concept of center of pressure to the plantar structures of the 1st MPJ. The motion of the first toe toward the second (or away from the second: hallux varus) is caused by a force couple. As the fibular attachements are cut you are changing the location of rearward force applied to the hallux.

    That surgeon may not have been able to describe a force couple, but he certainly understood biomechanics. This is not angle of dangle biomechanics, it is real biomchanics.

    I would bet that a surgeon who understands that example of mechanics would have fewer bunions return and fewer incidences of hallux varus. There was a phase in surgery where the fibular sesamoid was removed to prevent reoccurence of the bunion. The example above seems more like "surgical precision".


    Eric Fuller

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