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Should We Still Be Using The Term ‘Ankle Joint Equinus?’

Last November, when I was at the Federation Internationale Des Podologues (FIP) World Congress meeting in Miami, I had a conversation with a Canadian podiatrist about ankle joint equinus. He told me he never sees it in practice. This struck me as odd because he and I agreed on many foot and ankle biomechanical and orthotic prescription issues. In my experience, I see ankle joint dorsiflexion restriction all the time in all my patients, especially athletes. 

This conversation made me wonder if our podiatric terminology needs an adjustment. I have been talking about ankle joint dorsiflexion restriction for years. I know that, in my mind at least, this term is synonymous with ankle joint equinus (AJE). I have always felt that when colleagues state they do not see limitation in range of motion (ROM) of the ankle, it is usually because they are not regularly measuring and recording dorsiflexion ROM in most of their patients. How colleagues are measuring ROM is often an issue as well. However, I am now wondering whether the terminology we have been using since we were in podiatry school is confusing.

There was a very good article on equinus in the September 2014 edition of Podiatry Today called, “Understanding The Biomechanics Of Equinus,” written by Craig Clifford, DPM.1 In this article, Dr. Clifford jumps right into describing the differences between stage 1 and 2 of ankle joint equinus, and what gait issues often occur when patients have between five to ten degrees and less than five degrees of ankle dorsiflexion ROM. He even mentions pressure mapping changes that can occur with these limitations in ROM.

At the top of the article by Dr. Clifford is an X-ray image of an obviously plantarflexed foot at the ankle. 

However, because of this image and the age-old terminology “ankle joint equinus,” I am wondering if this is what most practitioners think of as an ankle joint restriction. Do they believe that if the foot can at least get to 90 degrees on that ankle, then everything is okay? Is the terminology describing “equinus,” which refers to an equine or horse’s lower leg and hoof, the real issue? 

There is a ton of information on how ankle joint dorsiflexion limitation of ROM can affect almost every aspect of foot and ankle pain as well as contribute to knee injuries. I am not going to list all of this out today though. All I want you to do, if you have read this far, is ask yourself why you may not be seeing ankle joint dorsiflexion ROM restriction in most of your patients. Once you have answered that question, think about whether you need to re-evaluate your exam protocols and see if your observations change. 

I sincerely hope that some of you will do this as we all need to reassess our clinical processes from time to time. No one is perfect.

Until next time, cheers!

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. Clifford C. Understanding the biomechanics of equinus. Podiatry Today. 2014;27(9):38-44.

Comments

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Since we do not have a reliable method to measure pure ankle joint range of motion in the clinical setting, this discussion is futile. What clinicians currently do is measure "foot and ankle" range of motion in a static condition and then mistakenly assume that this measurement predicts how much motion is used by the ankle during dynamic gait. The truth is that these measurements are misleading in suggesting that they actually measure ankle joint range of motion. To further complicate, we do not know how much pure ankle joint range of motion is required for "normal" gait.

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