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Blake Inverted Orthotic Devices

Discussion in 'Biomechanics, Sports and Foot orthoses' started by Rich Blake, Dec 22, 2013.

  1. Rich Blake

    Rich Blake Active Member

    Members do not see these Ads. Sign Up.
    I would love to be a source of information on the Blake Inverted Orthotic Devices that I designed many years ago. I have many modifications and thoughts on the technique to share. I am hopeful that this may be the right forum for such discussions. Dr Rich Blake:hammer::hammer:
  2. Grover

    Grover Member

  3. Rich Blake

    Rich Blake Active Member

    Dear Dr Greaves, Thanks for appreciating my blog. I am so honored that it is helpful to you. Let me know if you have questions as I get my feet wet in this Podiatry Arena website. Rich Blake:santa:
  4. Admin2

    Admin2 Administrator Staff Member

  5. Rich Blake

    Rich Blake Active Member

    Golden Rule of Inverted Orthotic Devices: Even with the most severe pronation, start the patients at 35 degrees inversion to get their body use to such a change.
  6. OK, you got me... why 35 degrees as oppose to any other number?

    Merry Christmas, BTW.
  7. Rob Kidd

    Rob Kidd Well-Known Member

    There is no magic number. I used to have students tell me that 4mm of medial heel rise equals 4 degrees of hindfoot post. - They were taught by Dick Bogdan, though whether this came from him is not known to me. when I sat down to work it out, in fact 4mm does closely approximate to 4 ' - but that does not excuse the removal of the thinking process.

    In fact, the correlation between "degrees of posting" and "degrees of correction" are far from good. It may well be that Blakes' 35 degrees gives him 5' of correction, or more, or less - who knows? But I do know that a great deal more thinking and less blind numbers would help. Happy Christmas, Rob
  8. efuller

    efuller MVP

    I've never had any problem with people getting used to a medical heel skive. Do you feel that it is the increased arch height that is harder for people to adjust to?
  9. Rich Blake

    Rich Blake Active Member

    When I make a pair of Inverted Orthotics, a 35 degree correction is equal to (on average) to a 7 degree inversion. This is my 5 to 1 rule of orthotic positive cast correction to heel correction. Some labs I find fill the arch in more on the cast so that the correction is less than 5 to 1. The individual practitioner should measure the relaxed calcaneal stance position without and with the Inverted Orthotic Devices to get a feel what the lab tends to give them. If you truly give a patient a 7 degree inversion correction, I think that is a good change to start with and you have to see how the knees, hips, low back and feet tolerate such a positive change. In patients with 13 degrees of heel valgus, you may start with 35 degrees and eventually increase the correction. Dr Rich Blake:bang:
  10. Rich Blake

    Rich Blake Active Member

    Hey Rob, Thanks for the great comment. I have worked with some many podiatrists and labs that it would be impossible to get on the first try the exact number you need for posting any individual patient. On the same patient, you and I may post different amounts for many different reasons. These include: variability in measurements, goal of % of correction desired, knowledge of technique, etc. I think however, as a profession, if you have a severe pronator which needs full biomechanical support to help their chronic knee pain, you should be able to give it to the patient. The beautiful art of the process is always rewarding. Dr Rich Blake:santa:
  11. Rich Blake

    Rich Blake Active Member

    Hey Eric, thanks for the note. Many orthotic devices fail when they do not provide enough support so the arch collapses on the device. Of course, over correcting the proximal one half of the device (Inverted or Kirby) will cause lateral slide of the foot and some pain. Over correcting the distal one half of the device will jam the first ray. Getting used to the higher medial arch in the Inverted Orthotic Technique is of course easier in a Pes Cavus that pronates than a pes planus. I also find that with my Kirbys. Alot is lab technique and this is where I hope I can help standardize. The max medial arch height should be under the first cuneiform. If that same support goes under the first metatarsal, it will block first ray plantarflexion. Dr Rich Blake:dizzy:
  12. ijanssen

    ijanssen Welcome New Poster

    Dear dr. Blake,

    Thank you for your post. I'm sportspodiatrist in the Netherlands. I'm very interested in the Blake inverted Orthotic devices. Unforntunately in the Netherlands they don't teach us how to make them and it isn't used in clinical settings. Since I'm working a lot with hard materials, ie carbon for cyclists, I think your methode is really usefull. So I was wondering is there a 'manual / student guide' in which the technique is described?

    Best regards,

    Ingrid Janssen
    Sportspodiatrist / manual therapist
  13. Rich Blake

    Rich Blake Active Member

    Hey Ingrid, Thank you so very much. I would be happy to put together a guide with your help. Look at the information in my blog on the Inverted Technique first. Then, we can start seeing where we need to go. With varying degrees of training, a proper manual can only be designed if I know our common grounds. Dr Rich Blake:pigs:

  14. Rich Blake

    Rich Blake Active Member

    When I am designing the Inverted Orthotic Technique for over pronation, there are many instances where protecting the lateral column of the foot is crucial (for example, someone with pronation but lateral ankle sprain history). In these instances, you can simply make sure you have a high lateral heel cup of 23 mm or higher and a lateral phalange. You can add a Denton Modification (lateral arch fill) if you are using a standard plastic and rearfoot post ortho. You can use the Fettig Modification if the cast captures an everted Forefoot deformity and you want to build that into the positive cast along with the Inversion. Dr Rich Blake:hammer:
  15. joejared

    joejared Active Member

    When a foot is supinated, the mid-tarsals twist/shift from proximal to distal slightly from medial to lateral. It's not uncommon for the labs I work with to include a code to move the medial arch peak proximal 5~10% of the total length of the device for a better fit.
  16. David Smith

    David Smith Well-Known Member

    Dear Dr Blake
    Thanks for venturing onto PA, I have over many years read papers and discussions describing and instructing how to make and use the Blake inverted device. Like another poster said, it would be great if there were a book written by you that took us thru the whole process of your thinking on the prescriptiion, design and manufacture of these devices.
    Once again I have been reading thru your blog on the subject but once again I come up confused about how the Blake device fundamentally differs from a normal cast, pressed or milled orthotic shell with a high degree of medial posting or wedging?
    I can see that you have spent a lot if time fine tuning your designs so that they fit better, give more comfort, off load the lateral column and stop slipping, all of which is very important and useful and very instructive and time saving to me and others when designing a highly inverted device, is that the main advantage of following your technique or is there something more fundamental and advantageous in the way you invert the cast? I'm eager to learn because I may be missing out on an important intervention and because labs in the UK (that I use) don't understand the process and so cannot produce such a device and even if they did I would not be sure what the device was doing in terms of its biomechanical effect (that would be different from my usual designs) and so how would I apply it well to a particular patient.

    Regards Dave Smith
  17. Rich Blake

    Rich Blake Active Member

    Hey Joe, Sounds like they are moving the arch more proximally to avoid any lateral instability caused by a medial arch in a supinated foot. And, that is sound practice. They need to make sure the lateral heel cup and lateral phalange are in place as well. If they can place a Denton Modification (lateral arch fill), they will work wonders. Rich Blake
    Thanks for your comment.:drinks
  18. Rich Blake

    Rich Blake Active Member

    So Dave, You have given me a challenge. We really do not know the starting point in the process between you and I. I will write my manual in early March and post on my blog. Between now and then, I will post more and more about the technique to make sure everyone who uses it can go step by step. I am happy to work with labs. A particular lab interested needs to send me a cast at Dr Rich Blake, 900 Hyde Street, San Francisco, Ca, 94109. Request a 25 degree Inverted Orthotic Device. The labe should make a separate cast and orthotic so that they can see the similiarities and differences when they get mine version back. This is a good starting point. Dr Rich Blake:drinks
    Last edited: Dec 31, 2013
  19. joejared

    joejared Active Member

    Based on this video, I think I'd be more likely to recommend making the device thicker on the lateral side, accomplishing the same goal and minimizing labor. In oretek, it's as simple as modifying a design code:

    LPT=PT*1.4 ; Increase plastic thickness by 40% on the lateral side of the device.
    LTAPERT=PT ; optional disable feathering

    Thanks for the clarity on the 5:1 ratio for correction values. It explains why the numbers we use are so low in terms of angle.
  20. David Smith

    David Smith Well-Known Member

    Ok so I have a particular patient in mind: she has medial knee pain but also lateral STJ instability due to valgus forefoot, lateral stj axes and genu valgum. Both feet are extremely pronated in stance and my diagnosis in tension stress in the medial knee ligament and pes anserine bursitis. Pressure mat scan indicates she tends to weight bear on the lateral aspect of the foot. She has a secondary complaint of lateral ankle pain, which I Dx as sinus tarsi compression syndrome.
    So you may be able to see the picture, high pronation moments from GRF lateral CoPP resisted by the sinus tarsi and high knee abduction moments, due to same lateral line of force, resisted by medial soft tissue and internal torsion moments resisted by the semi ten, sartorius and gracilis at the Pes A. Therefore she requires the plantar CoP to move medially to reduce abduction moments and pronation moments, which will in turn reduce int torsion moments.
    She has tried Apos therapy and lots of physio type therapy from other clinicians without reduction in any painful symptoms. I have prescribed 7dg rearfoot and 3dg forefoot medially posted orthoses with 1st ray designs and ankle mobs to facilitate digital plane progression.
    This resulted in resolution of lateral ankle pain but no improvement in knee pain after 6 weeks. After adding reverse Morton's extension I will review again in the new year.
    NB there were no issues of comfort or patient compliance but she did find them even more comfortable with the addition of M ext and top covers.
    Dr Ritchie, do you think that your inverted device could improve the knee pain without causing lateral instability and inversion sprains? Can you describe how? If so could I order direct from your lab i.e. do you mail to UK? If so can you say what sort of cost they might be?
    Last edited: Dec 31, 2013
  21. Rich Blake

    Rich Blake Active Member

    Thanks for the wonderful description. If I am getting it, the patient's foot would be supinating due to the lateral subtalar axis and high forefoot valgus, but the genu valgum wins and drives a severe pronation force at the knee and ankle/rearfoot. I have found that to be a 50/50, with half the time the knee wins and half the time the foot wins.
    When you made your orthos, you in essence, ignored the forefoot valgus and inverted the foot 3 degrees after forefoot loading. This is quite a standard runner's orthos in the US helping with the running limb varus created by the narrower base of gait. And definitely, if you use a 35 degree inverted orthotic with or without the Fettig modification you will get probably 7 degrees of correction at the foot working up at the knee. The role of the Fettig is to do place the intrinsic forefoot valgus in the cast while still getting an overall 7 degrees of inversion force at the foot. You may like that if you worry about lateral instability.
    When dealing with such a patient, I try to let them know that predicting how much correction any foot orthotic device will give them is somewhat difficult. I would love to know your observations of the stability gained by your present orthotic device. I grade my corrections A, B, C, D, and F, with plus' and minus'. Was your correction with the 3 degree inversion (end point of inversion with your technique is the amount of ff wedge applied) an B+ or less in controlling pronation at the foot. An A+ of course insinuates possible overcorrection and lateral instability. And what was the correction obtained at the knee. Your description is of a collapsing medially knee with over pronation of the foot. Was that dramatically, or somewhat improved by the orthotic device? Does his website allow videos to be shared? You could send a video of the foot before and after, and the knee before and after.
    Somewhere in our exchange, if you decide to send me a cast, I would charge $100 US to make plus shipping back to you. I would keep the molds, and do one free redo based on patient tolerance or objective results (you would just be charged shipping). The goal is really not to make orthotics, but to show you the results. So, eventually, your lab would have to be trained. The lab part difficulty is in the standardization, so I have to work with a few trial patients with labs, but the technique of making is quite simply. The complexity is in the ordering process.
    I hope this is okay. This is just the interchange I wanted when I opened this thread. Dr Rich Blake:bash:
  22. efuller

    efuller MVP

    Joe, without knowing where you would put the arch peak in the first place, it's hard to know where 5-10% more proximal is. A question for you and Rich, where, in terms of anatomy of the foot should the arch peak be?

    Rich, I thought you discussed construction of the inverted orthotic technique in Ron Valmassey's book. I recall a bit written somewhere that said after you invert the cast and create the balance platform, the medial arch of the foot will be higher, to much higher off of the ground. Then, you add medial arch fill to make the arch of the orthotic close to what it supposed to be. Rich, did you make that statement? If you did, how would you determine how high the arch is supposed to be?

  23. Not where the STJ axis be.
  24. David Smith

    David Smith Well-Known Member

    Dr Blake
    What is a Fetting modification?
    I'll get back on the rest of your queries after I see this lady next. I do regularly use video but I don't think the resolution or precision is good enough to determine minor kinematic variations that you describe with your grading tool

    Thanks for your reply - Dave Smith
  25. Rich Blake

    Rich Blake Active Member

    Hey Eric, Thanks for the note and I copied my blog post on arch height within the positive cast. When I first introduced the technique, I was only using Rohadur so I kept the arch height down and used plantar fascial grooves. In the early 1990s, I began experimenting with polypropylene and it's affect on arch height. Because of the greater flex, I found I needed to raise the arch height and remove the PF grooves to achieve the same corrections. Now, over the last 15 years, I have pushed my corrections higher with better lateral stabilization with Fettig modifications, Denton modifications, higher lateral heel cups and more standard lateral phalanges. Rich

  26. Dr. Steven King

    Dr. Steven King Well-Known Member

    Aloha Rich!

    Please have a seat on the floor next to us and let us observe some great gaits.

    I was lucky enough to also be a resident of Dr. Bogdan's.

    As you may know a few of us are working on a new advanced composite midsole orthotic system for footwear. What type of accomdations to the inverted orthotic would you expect to need to make when we add a spring lever simple machine under it? such as when;

    - the orthotic (cradle component) is more rigid but the spring plate is more flexible?

    - for the drop off of the metatarsal heads distal to the cradle component onto the spring plate? i.e. should we lower the correction/ arch height?

    - would posting the sping plate pivot in inversion assist and lessen the orthotic (cradle) correction/ arch height?

    I have my thoughts on these questions but would appriciate your input.

    The new composite materials are exciting and dynamic to work with perhaps more than the old Rohadur and other non-reinforced plastics and foams.


  27. efuller

    efuller MVP

    Rich, your blog post had a nice description of where the highest point of the arch should be. I use a slightly different method of where to choose to place the highest point of the arch. I put the highest point at the navicular tuberosity. This will problably be pretty close to your point. I didn't see where described how high to make the arch. The highest point can be in the same location and be 10, 15, 20, 25, or 30mm high when you add in the arch fill.

  28. Dr. Steven King

    Dr. Steven King Well-Known Member

    Aloha Rich,

    We hope you have a great birthday this week.

    I am sorry if my previous questions may have put you on the spot.

    We are doing our best to start a dialog here on Podiatry Arena. We hope that you could provide input as to how you would adjust your orthotic technique to our new technology.

  29. Rich Blake

    Rich Blake Active Member

    Thanks David for your interest in the Fettig Modification of the Inverted Orthotic Technique. Due to your question, I placed a post on my blog today describing the basics that I hope will help. It is a combination technique of rearfoot inversion with forefoot valgus/everted deformity support. Hope it helps. Rich


  30. David Smith

    David Smith Well-Known Member

    Ok Dr Blake, thanks for the link - I understand what you mean by a Fettig Mod now.

    Do you have problems with shoe fitting with the large inversions?

  31. Rich Blake

    Rich Blake Active Member

  32. Rich Blake

    Rich Blake Active Member

    Definitely Dave, many of my patients have to go up a half size and many need a hybrid model for other shoes (cross between athletic and dress). I maximize the width in all my athletic patients which really feel comfortable playing sports (no where for them to slide to), but torture to local shoe stores. At least with more correction, you need less correction from the shoes, so patients can sometimes get away from motion control and into stability shoes. Rich
  33. Dr. Steven King

    Dr. Steven King Well-Known Member

    Mahalo Rich,

    The APMA National in Honolulu this summer,, surfs up!

    Your Quote,
    "When we design functional foot orthotic devices, we are trying to shift weight forward (less flat footed) and eliminate the medial to lateral sway. Straight sagittal movement is preferable in most activities. With your lever system to move the body forward easier, definite changes may have to be made in the orthosis like less heel posting."

    The interesting thing about this advanced composite spring lever orthotic is that by changing the pivot shapes, dimensions and locations we can greater influence gait with more degrees of freedom than is achievable with the current plastic and foam footwear systems.

    We welcome your knowledgeable input.

    --For instance, this weekend i ran in the Maui Whale Day Half Marathon (in combat boots again) with an orthotic with a triangular shaped spring pivot with the apex of the pivot pointed towards the forefoot. This allowed my forefoot to have more degrees of motion for inversion and eversion. I have built systems that do the same for the rearfoot as well. This was a very nice modificaition to accomodate for the the roadside with a cantilever slope . If we use a staight pivot then we can better eliminate the medial to lateral sway, if a patient would need this.

    --For instance the pivot height of the cradle pivot was at 10mm and the sping pivot at 8mm, this created a declining plane (shifting weight forward and less flat footed). If we built the pivots in reverse (forefoot higher than rearfoot) we would create an incline plane and the shoe would act more like a Newton shoe or Earth shoe with a negitive heel.

    If we think of truely functional and dynamic orthotics we must start thinking of using dynamic spring plates to their full potential. We believe this system is the first to really try to achieve this.

    We think that your high inversion orthotics will be used with system because that's what some people need.

    You are the only person on Podiatry Arena thus far that has shown a basic understanding of the mechanics and physics of this tech. A big big Mahalo Rich.

    A Hui Hou,

    Peace starts with a smile.
  34. Rich Blake

    Rich Blake Active Member

    Thanks Dr King (Steve) for your kind words. What you are describing is truly the next step in biomechanical change. We have had a explosion in orthotic devices that will keep biomechanical health care providers busy learning when to use. We have had an explosion of shoes affecting biomechanics. We are understanding better the biomechanics of structures above the foot that influence us. And, now you are beginning a process to further influence the biomechanics. A spring lever system more powerful in producing motion, where an orthotic device is more powerful in stabilizing. Good luck in your experiments. Rich Blake:cool:

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