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Just trying to get a better understanding and clear up some confusion.

Kevin has often talked about the maximum pronation test to determine if the subtalar joint is at end range of motion when standing.

Eric has talked about the maximum eversion height, being how far the patient can lift the lateral metatarsals off the ground. My understanding is that is used to help determine the maximum amount of forefoot valgus posting.

Is that understanding right? Can someone take the time to explain in more detail what is the usefulness of both tests? What is trying to be found out by them?

Thanks in advance

 

The principle is to not to attempt to evert the foot farther than it can go. When you do that, you will tend to get pain in the sinus tarsi. So, you need to know how far the foot can go. Root et al, attempted to do this by looking at heel and leg bisections. However, the inaccuracy of the lines makes it nearly impossible make predictions with their calculations. The maximum eversion height measurement the patient is asked (to use their muscles) to evert as far as they can go. You can look at the caclcaneus as well the height of the metatarsal head off of the ground to see if either move when the peroneal muscles contract. The reason that that I feel that maximum eversion height is important is that sometimes you will see a calcaneus that does not move (the STJ is maximally pronated and has no further eversion available) and the forefoot does lift off of the ground because there is range of motion in the midtarsal (or other) joint (s).

The maximum eversion height is range of motion that you have to "use up" to increase load on the lateral column. Increasing load on the lateral column is good for feet that have too much load on the medial column.

Eric

 

Thanks Davinci and Eric
Yes, I have picked up on a confusion between what Kevin and Eric are saying - they are different things.

Eric's explanation of what he has been saying is my interpretation

What Kevin is saying (I think) with the maximum pronation text is that you just try to get them to pronate the STJ more and maybe help them by internally rotating the tibia to see if they have any eversion left at the joint. Those with a more medial STJ tend to have less or none available.
The main implication of this test (for me) is that those who are at end ROM will respond very different to lateral wedging (eg for medial knee OA) than those who have a range of motion available.
@Kevin Kirby - is that understanding right? Any other implications?

 

I check both of these and record measures of both. Eric is correct about needing to valgus wedge the forefoot for those who have too much ROM when the Heel is near or at vertical AND they have maxed out their STJ pronation, a la Kevin's version of the test. I like Kevin's test from the perspective of knowing which patients are maxed out in STJ pronation in stance. This can clue us a lot to how those feet will function in gait, and where they may have to move forces and compensations to make up for this issue during gait. Craig's point on those with medial knee pain is excellent as well, as how can we expect to pronate / valgus heel post, a STJ that is already maximally pronated. Technically we cannot, though we could of course lower the medial arch height and the heel cup medially and maybe see some changes in some? Case by cast I'd say. Also, on the lateral FF eversion test of Eric's, you will often see patients who cannot give you any or more than 1-2mm of lift in that lateral column. Beware overposting these feet at the medial heel and at all under the lateral column as this can increase risk for bone stress injuries and pain in that lateral column by shifing the forces from medial and overloading the lateral column. These tests need to be studies, but i've been using them for 10-15 years adn recording data. Also, as a last note, I have found that if you add a heel lift of about 2-4mm to the feet with max STJ pronation, you can often pick up a couple of degrees of available pronation but relaxing the pull of the posterior musculature, namely the achilles tension. This should be studies and validated too, but for many of us we know it helps and is part of that core of Craig's go to orthotic prescriptive elements that he discusses in his boot camps.
Cheers,
Bruce