Pathologic Ankle Rocker: Part 2. “Passing the Buck Proximally”
This was an unexpected follow up blog post from yesterday’s piece we did on the rigid flat foot. We were purging some files from an old computer and came across these 2 videos. We are not even sure where they came from. They were AVI files from probably 2 decades gone by; they reminded us how long we have been at this gait game and how many great patients have taught us along the way.
Yesterday we learned that if the ankle rocker (dorsiflexion) was impaired that we could ask for the motion to be passed into the midfoot via hyperpronation in order to get the tibia to progress past vertical to enable the body to pass by the rigid ankle mortise rocker. (Remember from our previous teachings that there are 3 rockers in the foot. First there is heel rocker, then ankle rocker, then forefoot rocker. Each is essential for normal gait. You must understand the 3 rockers to understand gait and to recognize gait pathologies when they present.)
So, yesterday we saw a strategy of pronating excessively through the midfoot to artificially trick us into thinking we have more ankle rocker then we actually truly did. So this was a “pass the buck” into the foot. Today however we are going to show you a very atypical compensatory choice. Today this client shows that with a rigid and/or strong enough arch that the arch doesn’t always need to be the part that gives in to enable more rocker. Today this client chose a vertical strategy.
You are going to have to study these videos closely several times, this is a critical learning and teaching point today. The problem is the left ankle in the video.
This client has chosen to go VERTICAL when they hit the ankle rocker limitation. Once they achieve their terminal range at the ankle mortise joint (the tibio-talar joint ) their brain realized that moving forward at the ankle was impossible. Since the midfoot did not collapse and give in, as in yesterday’s case, they had no choice but to “pass the buck” proximally into the kinetic chain. In this case we see that the knee was the next vertical joint. Now, they have 2 choices, either hyperextend the knee to enable a forward lurch of the body mass past the ankle rocker axis or “go vertical”. In this case you can see the early heel rise (we refer to is as premature heel rise). Frequently a premature heel rise can force knee flexion but in this case the rise just kept going vertical and forcing them into the use of the gastrocsoleus group and thus forcing a lift of the entire body. If you look hard you can see a greater development of the calf muscles on this side from doing this for years. (Oh, wait, memory data dump here…..we are recalling this case, it was the result of an old motorcycle accident. A student sent us this video back in the 1990’s when we were teaching at the university.)
What is interesting here is that if you think hard, and this will be a new thought process for many readers, that when he goes into heel rise he buys himself more ankle range again. You see, he first met the end range limitation of ankle rocker which appears to be about 90 degrees and then he hits the bony block. If he goes vertical into the calf he is moving back into plantarflexion. This means that even though he is on the forefoot now, he has bought himself more ankle dorsiflexion range again. Now he has the option of holding the posture on the forefoot as rigid and then re-utilizing the new-found extra degrees of ankle dorsiflexion to progress forward OR, he can just move into FOREFOOT ROCKER (the 3rd of the rockers we meantioned earlier). This client is likely doing a bit of both, perhaps a little more of the forefoot rocker strategy.
You can also kind of see that this slightly shortens the time in the stance phase on this left side and causes an early dumping onto the right limb (which causes a frontal plane pelvis distortion compensation). This gives the appearance of a slight limp.
So, this was a nice follow up from yesterday’s principle of “passing the buck”. You can either ask for the motion from the next distal joint in the kinetic chain, or you can back up the kinetic chain and dump it into the proximal joint from the pathologic one (the knee in this case). Which one would you want, if you had to choose? It is a tough choice, luckily the body decides for us. IF you consider that luck !
Regardless, one has to stand in awe that the body will find a way to get the range elsewhere when it cannot find it in the primary motor pattern. And when the range has to be gained elsewhere, the muscular function has to change as well and prostitute the normal kinetic chain motor patterns.
Here is a tougher question for you. Would you want this phenomenon on one side and be unilaterally compromising (and thus have to compensate on the opposite side) the kinetic chain or bilaterally and have the asymmetry on both sides ? That is a tough one. There is no good choice however.
*Please do not try to help this client by putting a heel wedge in their shoe. You are just going to rush heel rocker into that bony block sooner and faster and speed up his pathologic stance phase. You will see his vertical strategy come even faster and thus pass the buck into the opposite right hip even stronger. It is a fleeting good initial thought because you are merely trying to help his poor calf muscles get to that heel rise easier, until you think about it for a minute.
When it comes to the feet, use your head. And, consider the Gait Guys, National Shoe Fit DVD program. Email us at : firstname.lastname@example.org