What Orthotic Modifications Do Podiatrists Use The Most?

I am often intrigued by certain orthotic modifications that my peers choose to use or not use when treating certain foot and ankle issues. I find it equally interesting that the use of certain orthotic modifications often appears to be regionally based on where podiatrists went to school and where they did their residency training. 

The image below shows many orthotic modifications that one can add to custom or even non-custom foot orthotics. Some of the ones left out of the picture include first ray cutouts, lateral forefoot wedges, heel lifts, medial flanges and plantar fascia grooves. I am sure there are others I have missed but hopefully not too many.

Despite all the different custom foot orthotic modifications available, very few of them have been subject to study to see if or how specifically they work. In fact, there are very few studies outside of literature focused on patients with diabetes that seek to understand these modifications.¹

To find any real data on what modifications most podiatrists use on their custom foot orthotics, you need to look to studies done primarily in Australia, New Zealand, the United Kingdon and Hong Kong. It would be nice to see more academic work done on this subject in the U.S. but if it is out there, I am having a difficult time finding it.

A study that was done in Australia sought to find a consensus between 24 podiatrists about prescribing orthotics for a patient with flexible flatfoot.² The practitioners mainly agreed on the orthotic material, polyolefin, which is the same as polypropylene, the use of a neutral heel post with the forefoot balanced to the rearfoot, and the use of a flat external heel post.² Other modifications considered in the study but not selected due to a lack of consensus included the use of plantar fascia grooves, first ray accommodations or cutouts, plantar fifth ray grinds, medial flares, medial and lateral heel skives and heel apertures.²

Another study done in Australia and Hong Kong looked at 1,000 consecutive orthotic prescriptions submitted to one foot orthotic lab in Australia.³ In their study, Banwell and colleagues documented all the different modification requests from posting to top covers to cast modifications, etc. The study authors observed three broad categories (“clusters”) indicative of increasing “control” of rearfoot pronation. A combination of five variables (rearfoot cast correction, cover shape, orthosis type, forefoot cast correction and plantar fascia accommodation) identified these clusters with an accuracy of 70 percent. Significant differences between clusters existed in relation to the age and sex of the patient, and the geographic location of the prescribing clinician.³

Later in the article, Banwell and colleagues observe that essentially three different clusters of prescription types are most often lumped together by practitioners in this study. Those three cluster types were a Root-type orthotic; an orthotic based on a higher medial arch height and the use of a medial heel skive; and an orthotic based on the use of the Blake inverted cast technique. The only other orthotic modifications used in all of these orthotic clusters were plantar fascia grooves or a cuboid notch.

I know we all have our preferences for the types of orthotic modifications that we will use day to day. I know as well that I often complain that most podiatrists will use the same prescription over and over for just about every foot type and problem that they see in the office. I have been guilty of this occasionally myself as I am sure we all are at times. Of course, what does matter is knowing what types of modifications work best for what you are trying to accomplish for each individual patient and his or her respective feet.  

Therefore, I want to talk a little more in depth over the next few blog posts about different sets and subsets of orthotic modifications, and when and why podiatrists seem to use them. Hopefully, it will be enlightening for us all.

Have a happy holiday season everyone!

Dr. Williams is a Past President and Fellow of the American Academy of Podiatric Sports Medicine. He is the Director of Breakthrough Sports Performance, LLC in Chicago. Dr. Williams has disclosed that is the Medical Director for Go 4-D and a consultant for HP FitStation.

References

1. Martinez-Santos A, Preece S, Nester CJ. Evaluation of orthotic insoles for people with diabetes who are at-risk of first ulceration. J Foot Ankle Res. 2019;12(1):35.
2. Menz HB, Allan JJ, Bonanno Dr, Landorf KB, Murley GS. Custom-made foot orthoses: an analysis of prescription characteristics from an Australian commercial orthotic laboratory. J Foot Ankle Res. 2017;10(1):23.
3. Banwell HA, Mackintosh S, Thewlis D, Landorf KB. Consensus-based recommendations of Australian podiatrists for the prescription of foot orthoses for symptomatic flexible pes planus in adults. J Foot Ankle Res. 2014;7(1):49.