Moderate to Severe Pronators are attracted to me. My reputation grew in the 1980s after I started having success with the Inverted Orthotic Technique for these patients. The technique is a laboratory skill set, the prescribing doctor just has to know how to differentiate normal pronation from mild pathological pronation from moderate pronation from severe pronation. Only a few laboratories around the country have taken the technique seriously, which has lead to wide variations how the technique is made. This is why I wrote the manual on the Inverted Orthotic Technique in 2019 to at least show labs and clinicians how I do it. I really start the evaluation of the spectrum of pronation during the first few moments of my examination when I watch a patient walk with and without shoes. If I had only one examination technique that I could do, I would also bisect their heel and measure RCSP. It is pretty easy for me, but let's look at these 2 observations separately and then together.
First, let us look at RCSP. There is the group of medial lateral instability patients that make any simple measure of pronation tendencies more complex. These are pes cavus patients who mainly pronate with with high degrees of forefoot vagus, or patients with high degrees of tibial or genu varum that pronate usually, or pronators with forefoot varus that must be compensated yet have laterally unstable ankles from post sprains. Let's forget them for now. Let's just focus on the typical pronators that you want to make more stable. Teaching heel bisection is left to our professor Dr Cherri Choates at the College of Podiatric Medicine in Oakland CA where I also volunteer. She does a great job and I rarely have to correct the students if she has already taught this. Every school will have a professor that will teach a skill set, so please call on your local school if you are needing a refresher.
I have attached 3 random photos sent to me by Dr. Ajitha Nair (Oakland).
Typical Heel Bisection using the lateral and medial boney borders
Hope it is easy to see both heel have several foot pronation marked by 14-16 everted heels
Separate Patient viewing the heel eversion correction: Right great, left still everted on CFO.
For the last patient above, the Rx would have to be compared to the RCSP and see if this was expected. I would even say that the left side is under-corrected and the right side slightly over-corrected. After noting this, and dispensing the the inserts, I then watch the patient walk in the shoes they brought in. This may be the time you ask them to buy new shoes since the old ones are too worn out. If that is the case, a good biomechanical gait evaluation regarding the orthotic devices and their prescription will have to wait until next visit. You will still have to determine if they are comfortable and stable enough to being walking in for the breakin process to begin.
The classic way for prescribing an Inverted orthotic device is the 5:1 Rule. 5 degrees of varus correction in the mold will equal 1 degree of heel inversion correction in real life. This is a general rule but pretty accurate and has held up over the last 40 years. So much of the technique is built on not having the lab give too high of a medial arch which will supinate patients. So, you measure RCSP and use the 5:1 Rule. The limiting factor I place on the technique is that 7 degrees correction, therefore a 35 degree Inverted device (5:1), is the highest initial correction I recommend. In the patient above with 14-16 degree everted heels, both are given 35 degree prescriptions. Remember every degree you change the average foot, you are making a 1/16th degree change. Therefore, 7 degree change predictably would be about 7/16 inch change (almost one half inch change in the lower extremity infrastructure).
Why is a 25 degree Inverted Technique more controlling then a 5 degree inverted pour? They techniquely should be the same, but I have found the Inverted technique pair more substantial. As a profession, we are starting to compare corrections with medial Kirby skives versus straight inverted corrections versus Inverted Techniques cants. It is so easy for you to get into the discussion of corrections by measuring RCSP barefoot and with the orthotic device you prescribed (called OCSP). If you asked the orthosis to invert an everted heel, what actually happened? Good to measure and then compare with what you find in gait. I tend to use 3 mm medial Kirby skives all the time and get 1-2 degrees of inversion correction in real time. I think it depends on the the shape of the heel. If the heel is flat, the Kirby skive gives more inversion "pop" to the correction, then if the heel was rounded. This is the same result I found with Inverted Technique corrections.
So, how do doctors prescribe the Inverted Technique? They can use the exact RCSP measurement with the 5 to 1 Rule? They can use the 3 categories of mild pronation (15 degrees Inverted), moderate pronation (25 degrees inverted), and severe pronation (35 degrees inverted). Or, if they have never used the technique, and typically only use it on severe pronators as an option, will use either 25 degrees or 35 degrees on everyone and see what happens. I am mentoring Dr Ajitha Nair now in her Oakland practice. I make some for her, and KevinRoot makes the rest. 95 % of the ones they make for her are 35 degrees Inverted since she typically measures 7 or more degrees of everted RCSP in her pronators.
