The Inverted Orthotic Technique is now also in eBook Form

https://store.bookbaby.com/book/the-inverted-orthotic-technique

Carlos Martínez Sebastian from Spain

Álvaro Gomez Carrión from Spain

     I am very proud of my accomplishments for sure, but humble enough (could be more!) and realistic enough, to know that your true worth is in how much you love (and not what you accomplish per say). This is why I love to teach, I love my students. They bring me great joy!! This is why I love to write and lecture, I love to help build up the collective we in the knowledge I know. It is another act of love. I have written articles, handouts, and of course, medical charts. My first attempt at some more serious writing was "Secrets to Keep Moving" published in 2016 following a small stroke. It was not welled planned, written okay, and never advertised. My next attempt was "The Inverted Orthotic Technique", a technique I have been working on developing for 40 years and which came out in English 2019, Spanish 2020, and Korean 2021. I am happy I could get this in electronic form in 2022. My next book came out this year in 2022 called "Practical Biomechanics for the Podiatrist: Book 1 of 4". This is an accumulation of all of the incredible teachers I have had over the years. These teachers have been Podiatrists,  Orthopedic Surgeons, Physical Therapists, but mainly my wonderful patients. Truly I have learned as much, if not more, from them as any other source of my medical knowledge. So, Practical Biomechanics is a blending of every aspect of my career, and I am so pleased with the love it shares. And, by the way, Carlos and Alvaro are now working hard on the Spanish translation along with writing a chapter themselves on Biomechanical Theories (Book 3). Thank you all for coming along on my journey with me, as you can see, I love to do things with others. Rich ﬞ

Thank You Dr. Kevin Kirby!!

     This post is a thank you to a Rock Star, so to be noticed will probably never happen!! Dr. Kevin Kirby from the Sacramento area of California has greatly influenced my beloved profession and my beloved field of biomechanics. He has his beliefs, and stays true to those beliefs, a trait I completely admire. 

     So, let me explain why this overdue thank you in cyberspace is happening today. Today, I saw a typical patient needing my biomechanical help. At 17, and a runner, he had already had his left accessory navicular removed, and was trying to avoid the same surgery on the right side. This is a small extra bone that 10% of the population has, and only 3% have on both sides. Lucky him. It is both aggravated by pronation, and can cause pronation by weakening the arch. 

     One of my measures of a patients pronation is called the relaxed calcaneal stance position or RCSP for short. This measurement is ideally vertical (standing straight up) or a few degrees in varus. For my patient he stood 6 degrees everted RCSP, so very pronated, and this matched his pronatory gait and pronatory symptoms. 

     The technique I use for this is called the Inverted Orthotic Technique. It is a highly corrected orthotic device, which I felt important for the need to let the patient run and attempt to avoid right foot surgery. These are both moderate to severe implied needs for maximal correction on my part.

The technique is based on a 5 to 1 orthotic correction to foot change. Therefore if I correct the foot 5 degrees I get 1 degree of foot change. 

     So, what happened? I gave the patient with 6 degrees everted RCSP a 30 degree Inverted Orthotic Device and the feet changed to 4 degrees everted. I realized I was a little wide with the heel cup so I lost a degree or so, but this is common when you are initially trying to grab the foot that the foot does not respond how you want it. 

     So, at last visit with the patient, I gave him the 30 degrees of correction with a 2 degree foot change, and ordered a new orthotic at no cost to the patient. I was committed to helping. I added a 3 mm medial Kirby to the existing mold (which normally gives me 2-3 degrees of change when added to the Inverted Technique). I called the dad a week later just to see how he was doing and he said that the new orthotic (that I was unhappy with) was far superior to his previous orthotics and he was really enjoying running in them painfree. 

   Today, I dispensed the 30 degree Inverted with 3 mm Kirby and his heels stood straight up and down at vertical RCSP. This was then reflexed in his gait walking and running. At times it is the Kirby Skive that makes the most difference, and at times the Inverted Orthotic that makes the most change. So, we are inseparable (since I invented and the trustee of the Inverted Technique) and I thank you Dr. Kirby. This is how Dr. Kirby works in the shadows in my office daily, and why his technique has been vital now for over 30 years. 

Thank you Dr. Kirby for always being there for me!!

The First Patient with the Inverted Orthotic Technique

https://youtu.be/TNGR9XqvNEQ

Flat Feet with Marked Heel Eversion: Inverted Technique

This patient has pronated flat feet with marked eversion of the heels. The Inverted Orthotic Technique will be utilized to attempt to place the heel bisection line close to vertical. You can measure the angle, and use a 5 degree cast correction for 1 degree of foot correction ratio. If the line is over 7 degrees everted, I stop at 35 degrees to get the patient used to this amount of support. A good starting point. 

Flat Feet and Obesity: Blog Post from Dr Lance Silverman

I hope this post is an eye opener for many. This has been common knowledge to many, but some scientific evidence is wonderful. Many podiatrists make orthotic devices for flat feet that can help with the development of some arches if caught early enough. Both my boys had flat feet and out grew the need for their orthotic devices as teenagers. In the early 1980's, I invented one such orthotic device technique called the Inverted Orthotic Technique or the Blake Inverted Orthosis. This blog has many references to that technique. The key is the recognition of the child that is flat footed and inactive. Children may not complain about their feet, but even at a young age, can ask to be carried too much, or not want to do the activities right for their age. Dr Rich Blake

New post on Silverman Ankle & Foot - Edina Orthopedic Surgeon

Obesity Linked To Flat Feet in Children by Lance Silverman, MD A new study out of King George's Medical University suggests that over 90 percent of overweight or obese children express symptoms of flat feet. The study based out of India examined nearly 400 children under the age of 12. 386 children were divided into two groups based on their body-mass index. Researchers uncovered that flat feet weren't isolated to children with elevated body mass indexes, but the condition was much more common in overweight children. "In kids with normal BMI, about 30 percent had flat foot," said Professor Ajai Singh, head of the pediatric orthopaedic department at King George's Medical University, who helped lead the study. "But in the abnormal BMI category, 90 percent of kids had flat foot." Grades of Flat Feet For the study, researchers broke down cases of flat feet into three different grades. The first grade involved an arch of the sole that was smaller than the normal height, while a second grade involved cases of flat feet where no arch was present. A grade three flat foot involved situations where the arch of the foot was reversed and the bottom of the foot was actually convex, bending outward slightly. "We found that 45 percent of kids had Grade 2 flat feet, while 43 percent had Grade 1 flat feet," said Professor Singh. "The remaining 12 percent belonged to Grade 3." Previous studies have uncovered a connection between obesity and flat-footedness, but they've also noted that the problem can be reversed if it is identified at an early stage in life. "In most of the cases, flat foot is reversible, while in the remaining, it is manageable," the authors wrote. "If kids come to us by the time they are five or six, we can help them with exercises and interventions like silica pads to be worn inside their shoes." So if you notice that your child has flat feet, or if the pediatrician has suggested that your child has an elevated BMI, consider some lifestyle interventions to help alleviate the condition. Help them get regular exercise and make an effort to provide them with healthy meals. A flat arch can put abnormal pressure on a person's foot, which can predispose them to other foot conditions. Like the authors said, take steps at an early stage to prevent it from becoming a bigger problem down the road. Lance Silverman, MD | November 16, 2016 at 1:29 am | Tags: flat feet in kids, flat feet obesity, flat footedness | URL: http://wp.me/p6p9tP-3aY

Inverted Orthotic Technique: Email Questions

Dear Dr. Blake,

sorry for my bad english,

 I'm an Italian podiatrist; I very interested about inverted technique. I have some questions to ask:

- Is it right to think Fettig modification only with inverted technique? and then, is it only used to correct a forefoot valgus associated with rearfoot varus? if no, when and how?

- Denton and Feehery modification are similar, when apply one or the other?

- In your daily treatment, do you often use these modification?

Thanks for your patience!

Dr Blake's response:

     Thank you for the kind email. I am happy to teach you. Please feel free to take the information I give you and ask any more. I will combine with this posting.  My wife and I hopefully will go to Rome next year on vacation. The Fettig Modification is a modification of the Inverted Technique only and used for the many patients with both a pronation tendency and a supination tendency. The Fettig can only be used in forefoot valgus (everted) feet, as it uses the forefoot valgus correction to be an anti-supination instrument. When the inverted technique controls rear foot pronation, the Fettig can grab that lateral column and slow down or stop mid stance to propulsive phase supination. The supination tendency can come from many causes one of which is rear foot varus, another unstable lateral column, or weak peroneals, or chronic ankle sprains, etc. The Denton modification, her sister lives in Rome, is an extrinsic lateral arch fill that wonderfully fills up the lateral arch  and helps block a supination tendency. The Feehery is an intrinsic raising of the cuboid and lateral anterior calcaneus that does the same, but you cut into the cast. Like the Kirby skive laterally, you have to learn when to violate the cast and when not to. I make orthotic devices as a process typically only violating the cast on the second modification when needed. This is the same general principle I typically use for the Kirby skive.
     Let us say that you have a patient with pronation and supination tendencies. They pronate mainly at contact, but due to chronic ankle instability, love to misstep and supinate at times (typically also at contact). For the pronation, you estimate they need a 30 degree inverted correction. For the supination tendency, they have a forefoot valgus/plantar flexed first ray we can use. So, you order a Fettig. You can also typically add a high lateral heel cup and lateral phalange, a Denton modification, and a full topcover to a forefoot valgus extension under the 4th and 5th metatarsal heads. 
     Let us say that you suspect initially, or you see at dispense, that the patient is not as controlled laterally as you would like. Your next orthotic device will be a lateral Kirby skive to the above cast, a Feehery cuboid skive, or both. And you  can also add more height to the lateral heel cup, and more height to the lateral phalange, along with a bigger forefoot valgus forefoot extension. The possibilities are endless. Please ask other questions. Rich

PS I use the Denton routinely (almost daily) and the Fettig modification 1-2 times per year. I probably use the Feehery once every other month. I relie a lot on stable shoes, lateral phalanges, forefoot valgus extensions.

     

Inverted Orthotic Technique Patent Request for the Kinetic Blake!!

After designing an orthotic device in 1981, it is fun now seeing it being used in various designs, etc. Here is a patent design for a product called the "Kinetic Blake"!!!

http://www.google.com/patents/EP2723280A1?cl=en

Bisecting the Negative Cast for Orthotic Manufacturing

I apologize for most of my readers that this means little, but this bisection line on the back of a negative cast to me is crucial in designing orthotic devices. To complicate matters worse, the bisection line must be "tangent to the curve on the lateral side of the heel", whatever that means. I know what it means of course. But, when you are learning this stuff, it can be difficult, and sometimes impossible to learn. The lateral side of the heel is the opposite side from the level, and looks fairly straight. When you use Root Biomechanics, 1 degree changes are important, so a heel bisection 2 or 3 degrees off, can be disasterous. With the Inverted Orthotic Technique, with a rough estimate of 5 degrees of cast inversion to 1 degree foot correction, the exact bisection is not as crucial. 

Inverted Orthotic Technique for Severe Pronation: A Study Attempting to Document what it Actually Does

In 1981 I designed the Inverted Orthotic Technique, also called the Blake Inverted Orthosis. It is well accepted in the world for helping patients, as this study states, but what does it actually do to the running mechanics is hard. I wish I was around the design of these studies to individualize the amount of correction and the modifications necessary based on Strike patterns. But, I am happy it helps patients every day around the world.

https://www.researchgate.net/publication/8077946_Effect_of_foot_orthotics_on_rearfoot_and_tibia_joint_coupling_patterns_and_variability?ev=prf_pub

Correcting Children with Flatfeet with Orthotic Devices

Custom Made Orthotic Devices with Blake Design Improves Arch Structure in Developing Children

http://synapse.koreamed.org/Synapse/Data/PDFData/1041ARM/arm-38-369.pdf

·        39 Flat Foot Children studied by x-ray evaluation over 6 years old (average age 10.3, range 6 to 14 years old) for a 2 year period to see if the arch developed with Blake Inverted Orthotic Design

·        Blake Inverted Orthotic Design is recognized worldwide as providing the most medial arch support

Orthotic Device cross section standard heel cup (right) and Inverted Technique (left)

Orthotic devices resting under Inverted molds (typically one foot more inverted than the other

Standard right arch and Inverted left arch

·        One study showed that if children were to spontaneously reduce their flat feet (grow out of it) it would be before 6 years old. Dr Ron Valmassy says it is predictable at any age, but 8 years old is the gold standard of knowing if they will grow out of it.

·        4 radiological angles (which measure arch collapse in the sagittal and transverse planes) and one standing angle (measuring frontal plane) were measured at the start of the study, 12-18 months into the study, and at 24 months.

·        Subjects were required to wear orthotic devices for 8 hours per day minimal

·        Exact Rx writing was used to individualize the custom orthotic devices based on the RCSP (Resting Calcaneal Stance Position).

This measurement, called the resting calcaneal stance position, changed from 8.0 everted to 1.9 everted with orthotic wear over the 2 years, and measures the frontal or coronal plane component. The ideal is 0 degrees or heel vertical measured exactly with a goniometer.





Here the exact angle is being measured with a goniometer.

·        2 of the 5 angles showed significant improvement, 2 of the angles showed improvement, and one was unchanged (the least predictive one generally)

·        Background Info: Blake Inverted Orthotic developed here at Center for Sports Medicine throughout the 1980’s. Dr Blake has lectured nationally and internationally about the technique. At one point, 17% of all custom made orthotic devices in Australia were this technique.

·        More Background: Bias of Pediatricians and Orthopedic Surgeons is that all children with flat feet will outgrow this, or at least there is no predictability in selecting children for orthotic devices. Dr Ron Valmassy developed the criteria in the late 1970s for predicting which children will not outgrow their flatfeet and also has lectured extensively.

·        Flatfeet: flexible and rigid. Flexible is the hardest to correct in adults and these were the ones chosen for the study (typically more ligamentous laxity than a rigid flatfoot). Flexible flat foot is much more common to see however in children, and can develop into rigid flat feet after the age of 22 when the adult ligament and bone structure is fully developed.

AP TCA is decreased as the arch gets better and the foot less splayed out (Angle 1)

Lateral TCA should get less as the arch improves (Angle 2)

Lateral TMA should get less as the arch improves (Angle 3)

CP should get greater as the arch improves (Angle 4)

·        RCSP changes  8.0 to 2.6 to 1.9  (less is good)

AP View TC Angle 38.4 to 38.1 to 29.6 (less is good) Angle 1 above

Lateral View TC Angle 47.3 to 49.8 to 47.3 (less is good) Angle 2 above

Lateral TM Angle 17.7 to 18.2 to 10.3 (less is good) Angle 3 above

CP Angle 11.6 to 14.7 to 16.0  (more is good)  Angle 4 above

Dr Blake’s comments:

·        Article used the Blake Design to customize the orthotic prescription typically not seen in foot orthotic studies (allowing the 5 to 1 rule of cast correction to heel eversion to create an equal and opposite force to control pronation)

·        The calcaneus is the best guide since it can be accurately measured in the sagittal and transverse planes (by the calcaneal pitch) and the frontal plane (by the RCSP) since it is trapped against the ground. The talus is notoriously a poor guide since it is influenced by the foot and ankle (and ankle positioning is not standard with these x-rays). 

Inverted Orthotic Technique to Correct Flat Feet in Children

http://synapse.koreamed.org/Synapse/Data/PDFData/1041ARM/arm-38-369.pdf

     I am so proud of this article published by researchers in Korea. It substantiates a claim that the Inverted Orthotic Technique, which I developed throughout the last 30 years, actually helps children with flatfeet improve (called pes planus). I have used the technique on 100s of children, including my own two children, starting at 3 for one, and 1 and a half for the other more pronated child. If your children have flatfeet, have a podiatrist evaluate if they should have orthotic devices and when. I have tended to never treat my family as a general principle, but in this case, I have felt the most qualified.

Video on Orthotic Modifications for Pronation Control

Inverted Orthotic Technique: Email Discussion

Dear Dr Blake,

I am a Bachelor of Podiatry student at the University of Newcastle in Australia. I am in my second last year of the degree and we are presently making your inverted devices.

I just have a question regarding one of the indications or criteria for your devices. In two lots of our notes it states 'NCSP of 8 degrees  or greater'. I don't understand why this would indicate a Blake inverted device, it doesn't seem to  fit with the other criteria. I was hoping you would be able to explain this particular point to me.

Regards,

Dr Blake's comment:

     Thank you so very much for your question. I am happy to answer all questions to this topic so dear to me. Fire away. We will have to look closely in our conversation at what is being said to make sure you and I are on the same page. The way I read what you are saying is that one of the instances of ordering a Blake Inverted Orthotic is if the NCSP (neutral heel position) is 8 degrees inverted or greater. And this is definitely one of the criteria, for it stands for a Highly Inverted Rearfoot Varus. With this foot type, using Root criteria and technique, you must now measure the RCSP (relaxed heel position) and see if it goes to vertical, pronates to the everted side, or stays inverted. When you attempt to control this foot with the Root Technique, you are just trying to stabilize even if the foot can be held near 3-4 inverted (close to neutral position). And it is hard to do this, with typically the foot is held close to vertical. If you think about the importance of neutrality, where the foot and ankle line up, you are actually no where close with the foot pretty pronated (even when inverted slightly). Problems can develop when the patient pronates farther than the device wants them to go. Say you want them to stay around 3 inverted. The patient has a 8 degree inverted NCSP, but the device is made around a pronated 3-4 degree inverted position (the highest inversion in Root Biomechanics). Typically being this far from neutral allows too much instability in the subtalar and midtarsal joints, and the foot can not be held at 3-4 degrees inverted (unless that is the end of the range). 

     In the same scenario, you are using the Blake Inverted Technique to not go from an everted position to vertical, but from vertical to an inverted position (same direction). A 40 Inverted Orthotic Device in a patient with a high degree of Rearfoot Varus, that really can not get to the everted side easily, typically holds the foot 8 degrees inverted (very close to neutral).  My starting point is 35 degrees Inverted, and for a new practitioner probably 25 degrees, but the positioning of these orthotics are so much better than Root since they hold the foot so much closer to neutral. 

     Okay, fire away with more questions now that I have confused you more. Rich

Inverted Orthotic Technique: A ProLab Discussion

This is a good discussion by Dr Larry Huppin from ProLab Orthotics on lab techniques. A 10 Degree Inverted Orthotic would correct the everted heel 2 degrees whereas a poured 9 degree inverted cast (a favorite of my partner Dr William Olson) will correct 2-4 degrees assuming that the arch is not overly filled in with plaster. This does not work of course with forefoot varus feet where over 3-4 degrees of inversion jam up the first ray. When the cast is poured 9 inverted, using the standard Root Balance Technique, there must be at least 6 degrees of forefoot valgus, to avoid sagittal plane blockaid (first ray jamming). 

http://www.prolaborthotics.com/Blog/tabid/90/EntryID/348/Default.aspx

Podiatrists Discuss Orthotics: A Podiatrist Only Blog Post (too boring otherwise!!)

http://www.podiatrytoday.com/inside-insights-on-orthotic-modifications?page=2

Inverted Orthotic Technique: Email Advice

Hi Dr. Blake! 

     I am a Certified Pedorthist out of Fort Worth, Texas. I have the opportunity to 
speak to resident podiatrists/physical therapists regarding foot orthotics. I am 

writing to inqure about how I can present your technique for the inverted orthotics. 
What I am in the dark about is who qualifies for these orthoses?

Dr Blake's comment: Thank you so very much for inquiring. Most podiatrists will use it when their initial orthotic device does not bring about the symptom relief and the pronation control combined. When the patient is still pronating on the device originally made, the Inverted Technique may help. Typically, most orthotics designed set the heel vertical to slightly (1-2 degrees) inverted. A standard 25 degree Inverted Correction gives the heel about 5 degrees of correction, thus over 150-200% more support. Someone like you, and the students you teach, will begin to see patients that need the technique right from the get-go. Many patients with moderate to severe pronation are started at 35 degrees, equivalent to a 7 degree inversion correction. Runners, who typically needed 5 degrees correction (25 degree cant) in their stability shoes, now need 35 degrees cant in their neutral/transition/minimalist shoes since the shoes give less support for pronation. However, pronation control is not the only reason to use the Inverted Technique. The varus positioning you get with the Inverted Technique helps many patients with frontal plane problems like Tibial Varum and Genu Valgum. 

 What conditions are indicated and which are contraindications? 
     I understand the simple rigid vs. flexible deformity, but which diagnoses have you come 
across that can benefit from this, apart from PTTD, unless that's the only one? 

Dr Blake's comment: It is really an understanding of pain syndromes that lead you to know about what matches up. When you watch someone walk, you typically can tell if their pronation is mild, moderate, or severe. The Inverted Technique, which ranges from 15 degree cant to 50 degree canting with medial column corrections and medial Kirby Skives, is for the moderate to severe pronators. And these pronators get into problems in many ways affecting the weakest link in the chain. What problems are related to pronation that I treat (you may ask?!! LOL)?

1. Bunions are increased with over pronation
2. Hallux Limitus/Rigidus pain is increased with over pronation
3. Morton's Neuromas symptoms are worse with pronation
4. Arch Strain is worse with over pronation
5. Lisfranc's pain is worse with over pronation
6. Cuboid pain, and instability, is worse with over pronation
7. Anterior Tibial tendinitis, and shin splints, are worse with over pronation
8. Plantar Fasciitis is worse with over pronation
9. Lateral ankle and subtalar joint (sinus tarsi syndrome) impringement syndromes are worse with over pronation
10. Achilles Tendinitis and Hamstring strains are worse with over pronation
11. Tibial Stress Syndrome and Fibular Stress Fractures are sometimes related to over pronation
12. Iliotibial Band Syndrome is sometimes related to over pronation
13. Lateral Knee Compartment pain is sometimes related to over pronation
14. Chondromalacia Patellae is sometimes related to over pronation
15. Piriformis Syndrome and Ilio psoas strain can be related to over pronation
16. Some cases of Low Back Pain are related to overpronation

The contra-indications to this technique are two fold. Most patients do not need it, because they have mild pronation, or are supinators, or poor shock absorbers, or their symptoms are related to limb length discrepancies. But, secondly, a contra-indication has to be the ability for the lab to design it properly. I have reviewed at least 10 labs, and most can learn, or do it well. But some, just do not get it. They typically make a painful over-exaggerated arch which hurts. When done correctly, the Inverted Technique, which emphasized heel correction over arch correction, is very comfortable. 

Also, is there a chart maybe that could show the different correction angles compared to the 
eversion angles that you find or is it all the 5 to 1 rule?
Dr Blake's comment: If you understand the eversion angles, and your measurement of 0-3 degrees everted is mild pronation in gait, 4-7 degrees everted is moderate pronation in gait, and over 7 degrees severe pronation in gait, we probably measure the same and the 5 to 1 is appropriate. I will try to do a series of videos on it soon explaining the various anti-pronation cast corrections.  

You can see all the cast corrections for the over pronators

     Is there a rule about the arch height change other than to make sure it begins to make its descent distal to the 

medial cuneiform for the first ray drop? That is, do you increase the arch or measure it pre-modification and add to/take away from any of that height? 
Dr Blake's comment: I am attaching a couple of posts on arch height. The arch height gradually gets bigger with increasing inversions, or adding a medial column correction, but a 15 degree inverted cast probably has the same arch height as a Root Balanced with minimal arch fill. You will see in my cast corrections video over the next couple of weeks how the arch gets higher. I will try to do that video for you first. You hit the nail on the head perfectly by saying that the most important thing is to make sure the maximal arch height is at the medial cuneiform to insure first metatarsal plantar flexion in propulsion. 

http://www.drblakeshealingsole.com/2010/09/inverted-orthotic-technique-determining.html


If there is a clear/ to the point document that I could show them, that would be great. Otherwise, I'll direct 
them to your blog. By the way, I am becoming a fan of the technique as I just recently had 
a patient with severe PTTD who has not been comfortable in anything (Richie style, Arizona 
gauntlets, UCBLs etc.). I made him some orthotics using your technique, along with the 
use of work boots to give extra stability, and he loves them!  Sorry for so many questions, 
but I was so excited from seeing the outcomes in that patient that I want to spread the word 
about this in an accurate/appropriate way. 
Thank you sir! 
Dr Blake's comment: I am just ecstatic it helped. Most of the readers will not know how uncomfortable, or just big, these other devices are. Being able to take a patient that most who put in a AFO, Arizona Gauntlet or UCBL, and make an Inverted Orthotic device work, is a wonderful gift to that patient. The Inverted technique also allows the most normal function of all those techniques, thus the best chance for good strength to be re-established. 

Thursday's Biomechanics Discussion of the Week: Possible Left Posterior Tibial Tendon Rupture

Boy, there are many hours of discussion here but I will stick to the obvious. This video shows a collapsed left arch probably following a posterior tibial tendon rupture. The posterior tibial tendon can no longer support the arch, so there she goes. Even though the patient is shown demonstrating the ability to do a double toe raise, I seriously doubt the patient could do a single leg toe raise. This helps in the diagnosis of posterior tibial rupture. The pronation force is so great, I would go right to a 35 degree inverted orthotic device on the left side only, and a more normal device on the right. 35 degrees is my highest starting point. 

Here an Inverted Orthotic Positive Device is being made for the right side. See how the high point of the arch under the first cuneiform, not the first metatarsal base. This is crucial at not blocking first ray range of motion.

This is opposite of our video where the left is flatter. Here is a pair of orthotic devices designed to correct more for the right side with an Inverted Orthotic, over the more traditional Root Balanced Technique on the left. 

Thursday's Orthotic Discussion of the Week: Pouring the Negative Cast and Building the Anterior Platform for the Inverted Technique

Dear Dr. Blake,

Thank you very much for your blog and for this post ! I've read with great interest your post from Podiatry Arena and, as a self educated person [in my country doesn't exist podiatric schools] I want to tell you that your post is one of the best, expecially from a practical point of view !

 I have a question which maybe seems stupid for you and I apologies for this. I personnaly have difficulties with anterior platform building so I kindly ask you to give me some instructions regarding the composition of the pink plaster from photos. In my practice I make it either too fluid or too rigid and simple I didn't succeed to build the anterior platform in the way you have described here !

I'm expecting with great interest March, when you'll post your manual !

Thank you for your kindness !
Respectfully,

Robert (name changed)
Romania

Dear Robert,
     I am always honored by getting emails and compliments, and especially from so far. Thank you so very much and I hope I can help. Here are some photos that I hope will help. More questions are encouraged.

Here is the initial set up for pouring of the negative casts to make them a solid positive cast. The most important part of the photo is my coffee cup since it is 6:30 am on a Saturday morning. One basin is for the soap solution and one basin is for the casting plaster to be used in making the positive cast. 

For 2 feet I am pouring the plaster to make a positive cast I use 5 cups of plaster and 3 cups of water. There is the 1 cup volume rubber pouring bowl. For 2 pairs of feet, 4 total, I will use 10 cups of plaster and 6 cups of water. The basin I use holds up to 15 cups of plaster. 

This is the Casting Plaster I use with 30 minute Set Time. 

It is also called Red Tag 30. 

I use a one cup bowl, but you can buy these bowls that hold 5 or 10 cups at once to make life easier at times. Here the plaster is in the bowl and will be emptied into the basin to begin the process. 

I have fillled the basin with 10 cups of plaster good enough for 2 averaged sized pairs of feet. If both your casts are for sizes 12 or greater, consider 12 or 13 cups of plaster. The water ratio is still 60% approximately the plaster amount.

I buy a soapy concentrate and dilute with water 50%. This is poured into the negative cast to saturate the bottom and sides. Any extra soap is allowed to drip out and returned to the bottle. This makes it so much easier to get off the negative casting material once the positive is dried. 

Here are the negative casts after having been soaked thoroughly with the soapy solution and then being tipped over to allow the soap to drain. 

The negative casts are then leveled so that the heel bisections stand perfectly vertical when poured. This is done with every cast so that the top of the cast represents a parallel with the ground. 

Here my talented brother Bob is pouring water in a 60% ratio to the plaster with some colored dye to make the plaster solution for pouring. One pair of casts typically need 5 cups of plaster and 3 cups of water. 

The plaster (mud!!) is mixed thoroughly to get out any clumps of plaster so that the solution is a uniform consistency. 

Plaster clumps are completely broken apart

Then the very smooth consistent liquid plaster is poured into the balanced to heel vertical negative casts.

My great brother Bob skillfully pours the plaster to make the positive casts set a heel vertical.

Here the negative casts sit after the plaster is poured

Typically you can pour up to 3 pairs of casts in one basin. That basin would have 15 cups of plaster and 9 cups of water.

Once the negative casts are poured, it is important to recheck the heel bisection to make sure it has remained vertical. 

After pouring, sticks are placed into positives to minimize breakage with the high pressure vacuum press. 

Once you remove the casting plaster, the first and fifth metatarsal areas are marked to define the anterior platform borders. You find the contact point on the first metatarsal (lowest point) and then place the line 15 mm closer to the arch. I like to then even the 5th metatarsal platform with that line, but the fifth metatarsal is normally a little shorter. The vertical lines are in the space between the first and second metatarsals and the 4th/5th metatarsals.

Here you can see the proximal line 15 mm from the contact point. This will be where the plastic of the orthotic device ends. You do not want the plastic to run under the weight bearing surface when walking or running. 

Here the nails are placed on the platforms to make the angle for Fettig Modification of the Inverted Technique. Here the medial nail under the big toe joint will set the overall inversion and lateral nail under the fifth metatarsal head for the forefoot valgus correction.

When I am working with plaster, I typically have 2 or 3 bowls going at once. The plaster has to be right, not too runny and not to solid, to apply and shape. It takes time to learn your plaster. I try not to stir it much, for stirring will make the plaster harden faster. I try to pour off the excess water once the bubbles stop, for too long with excess water makes the plaster to take forever to dry. 

I use wooden sticks soaked for 10 minutes or so for making the transition from anterior platform to the medial arch fill more solid during vacuum press. The high pressures can break the platform away from the medial arch without the sticks in place.

After the nails are in place, and the plaster the right consistency, place a piece of paper down to make the anterior platform. 

Gently stir the plaster to check the consistency

It is so important to play with the plaster and know it's consistency

and play some more!

And more

I place dye into the plaster to make the various parts of the positive cast stand out

Mix it in well

When the plaster is ready, place it on a piece of paper and press the positive cast gently down. It is important not to push too hard to distort the nails. It is important not to push too lightly and lose the angle set by the nails.

Here the anterior platform area of the positive cast is coming in contact with the plaster mound

Gently, but firmly, I press the positive down into the mud

Then I use a spatula to make the medial and lateral edges straight up and down.

It is important to check your angles, if off from what was ordered, immediately knock off the platform and start all over again.

This photo is out of order but shows the positive casts, after being poured, drying for 1 hour in the sun. 

Here the wooden stick is placed into the anterior platform to set further strengthen the area before pressing. The total length of the stick coming out of the platform and into the arch will be 1 and 1/2 inches in general.

Another view of the stick

The platform is being formed following the lines on the positive cast.

When cutting the anterior platform, keep the spatula moist with water to allow easier trimming.

Do not lose focus on the shape of the platform desired and outlined by those lines 

The medial and lateral sides will still need to be trimmed to go straight up and down from the positive cast.

Another view of the 20 degrees Inversion with 6 degree forefoot valgus in the Fettig modification of the Inverted Orthotic Technique.

Trimming of the sides with scrapper

Final product with anterior platform with medial and lateral expansions.