The whole is greater than the sum of its parts…

This week in Neuromechanics Weekly, we will explore proprioception and total hip replacements.

You would think proprioception (ie body position awareness) would be impaired in a total hip replacement (THR). Not according to this study (see below) BUT Balance, the dynamic interaction of proprioception and the ability to maintain ourselves upright in the gravitational plane AND GAIT were…

We remember there are 3 systems that keep us upright: vision, the vestibular system and the proprioceptive system (ie joint and muscle mechanoreceptors). A THR would effect mostly the latter, especially in this case, whee they REMOVED the hip capsule (capsulectomy). This, of course, would remove any of the joint mechanoreceptors, but probably not the muscle mechanoreceptors (ie spindles and golgi tendon organs).

Look at the conclusion “Compared with the healthy age- and sex-matched controls, patients with total hip replacement did not have any proprioceptive deficit. Patients required extrasensory input, and there was a delayed motor response. Gait and dynamic balance results also indicated the motor deficit and required a compensatory strategy. Restoration of the postural control in these patients is thus essential.”

So, they required a GREATER amount of sensory input and the response was DELAYED. This leads us to believe that is must be the integration of the systems that is the key.

The whole is greater than the sum of the parts… 

All this information is integrated in the cerebellum. Think about the 4 types of joint mechanoreceptors: Type 1 on the outside of the joint (tonic or respond to small movements); Type 2 on the inside of the joint phasic, or respond to large amplitude movements); Type 3, basically a golgi tendon organ type receptor, and Type 4, pain receptors. All this is taken away and they can still tell you where the limb is in space.

What does that mean? ..It means there are MORE receptors, somewhere, providing this info to the brain. They also required “extra input”. Hmmm…something needed to tell the brain that the action (in this case balance and gait) were happening. What was providing it? Muscle spindles and golgi tendon organs (see last weeks high heels post for more info); the former responds to length change and the latter to tension change.

The whole is greater than the sum of the parts.

Rehab it. Work on motor control strategies. Skill, endurance, strength; in that order. Ivo and Shawn. The Gait Guys. Exploring the literature to bring you the best of the best and help you to help others….better.

Balance and gait in total hip replacement: a pilot study. Nallegowda M, Singh U, Bhan S, Wadhwa S, Handa G, Dwivedi SN.

2003 Sep;82(9):669-77. AM J Phys Med Rehabil

Abstract OBJECTIVE:

Evaluation of balance, gait changes, sexual functions, and activities of daily living in patients with total hip replacement in comparison with healthy subjects.

DESIGN:

A total of 30 patients were included in the study after total hip replacement. Balance was examined using dynamic posturography, and gait evaluation was done clinically. Sexual functions and activities of daily living were also assessed. A total of 30 healthy subjects of comparable age and sex served as a control group.

RESULTS:

Dynamic balance and gait differed significantly in both the groups. Despite capsulectomy, no significant difference was observed on testing proprioception. In the sensory organization tests with difficult tasks, patients needed more sensory input from vision and vestibular sense, despite normal proprioceptive sense. Significant difference was observed for limits of stability, rhythmic weight shifts, and for gait variables other than walking base. Some of the patients had major difficulties with sexual functions and activities of daily living.

CONCLUSIONS:

Compared with the healthy age- and sex-matched controls, patients with total hip replacement did not have any proprioceptive deficit. Patients required extrasensory input, and there was a delayed motor response. Gait and dynamic balance results also indicated the motor deficit and required a compensatory strategy. Restoration of the postural control in these patients is thus essential. Necessary training is required for balance, gait, and activities of daily living, and proper sexual counseling is necessary in postoperative care.

http://www.ncbi.nlm.nih.gov/pubmed/12960908

hip replacement image from: http://www.wpclipart.com

champagne lady from: icr.org

When the toe extensors become short or tight.

Here is a really great video.

One of us was treating physicians for the Chicago Joffrey Ballet for a time in the early 2000’s. Feet like these were nothing new. For the most part there was amazing flexibility, amazing strength and occasionally some nasty bunions but not as often as one might think. What was clear however was that the majority of the population of feet seen were freakishly strong, amazingly flexible and with skill levels that most of us only dream of.

In this video we can see two things which we just highlighted. Full uninhibited ranges of motion and apparent strength. In order to have full ranges we usually see wonderful strength. When we see a loss of range of motion, frequently but not always, we see weakness of the muscles necessary to drive that range. In other words, if we had the strength we would have the ability to engage the full range because of that strength.

You have heard it here before, that when there is weakness in a muscle around a joint (since all muscles cross a joint) we will see a neuro-protective loss of range due to a neuro-protective tightening (we are using the word TIGHTENING very carefully, note we did not use the word SHORTNESS) of some related muscles in a response to attempt to stabilize the joint. It is not a perfect remedy, but what other strategy do we have ? Sadly, it is usually the strategy of the owner of the broken part to try to stretch that tightened (again, note we did not use the word shortened) muscular interval which then presents the joint again with the afferent detection that the joint is unstable and unprotected. So, more tightness develops and the vicious cycle continues. It is our hope that those that find they need to stretch daily will someday have a light bulb moment and see that they are doing nothing to remedy the vicious cycle. That searching for the weakness that drives the neuro-protective tightness (as opposed to true “Shortness”, which is truly physiologic loss of the length-tension relationship) is where the answer lies to remedy the joint imbalance.

Here this client has generous ranges of motion and highly suspected appropriate strength. The two often go hand in hand unless the client has the phenomenon commonly referred to as “double jointed” which is truly just a collagen abundance in the passive restraints (lets leave this as a merely generalized term for now, it is a topic of another blog post).

What we wanted to talk about here today was the plethora of tightness AND shortness we see daily in the extensors of the toes. How many of your clients have the flexion (toe curl, at all joints) range of the toes that this client has ? Not many correct ? But most have near full extension ranges of the toes correct ? This can only come down to one theory that must be proved or disproved. That being that the toe extensors are either tight because the flexors and plantar intrinsics are weak OR that the toe extensors are short because they have been in this environment of flexor-plantar weakness for so long that the tightness eventually morphed into a more permanent reduced length-tension relationship.

Go ahead, see if you can flex your toes or those of your spouse or clients as far at this dancer can. See if you have full range at the metatarsophalangeal joints like this dancer does. Very likely you will notice a nasty painful tension and stretch across the top (dorsum) of your foot. This is reduced length of the long and/or short toe extensors and likely fascial connective tissue as well. Heck, what else runs across the top of your feet ? Nothing else really. So, what is one to assume ?

Digit extensor tightness is rampant in our society. We have been in shoes and orthotics and stable shoes for so long that our flexors and foot intrinsic muscles have become pathologically weak. As the opposing pull of the flexors and extensors across the end of the foot at the metatarsalphalangeal joints becomes so imbalanced our foot has no other choice but to express this imbalance.

Is this why we see bunions, hammer toes, even gentle flexion of our toes even at rest ?

Yup, the mass population of feet we see are slowly going into a coma. The pattern we see most commonly is even a bit more complex however, it is not quite as simple as tight-short extensors and weak flexors and intrinsics. Looking at the functional neuro-pathology of the hammer toe proves the complexity of our compensations. Here is the most typical pattern (and hence the hammer toes that are taking over the earth):

• weak long toe extensors
• strong short toe extensors
• weak short toe flexors
• strong long toe flexors

This combination ends up in a functional/flexible hammer toe, and if left alone to fester, a rigid hammer toe in time.

From this combination you should now as the question, “So, when I attempt to put my foot and toes in the flexion positioning of this dancer in the video above what is the tightness i feel across the top of my foot ?”

Answer: functional tightness (and possibly shortness if it has been there long enough, which is likely for most folks) of BOTH the long and short digit extensors (EDB, EDL). Think about it, in the hammer toe position both are short, but for different reasons. The EDB because of the resting extension position at the metatarsal phalangeal joint and the EDL becuase it is wrapped around two distal chronically flexed interphalangeal joints in the presence of an ALREADY extended metatarsophalangeal joint ( which takes up EDL length).

This phenomenon occurs rampantly in the upper limb as well across the elbow, carpals and finger joints. It is a big component of TOS and carpal tunnel and of the multitude of functional problems that the elbow such as medial and lateral epicondylitis.

Why do you care ? After all we are The Gait Guys. Well, because most of us swing our arms during gait and what is pathologic in the upper limb can affect the lower limbs and gait. It is all connected after all, according to the song ……

Chronic disruption of the length-tension relationships of the toe extensors.

It is a bigger problem than you think.

Shawn and Ivo. Discussing the distal sister disease of polio……… affecting just the toes of course. Ever hear of Tolio ? (pronounced……Toe-Lee-oh). Just kidding.

Forefoot Valgus: What you need to know

Hi Shawn and Ivo,

With Forefoot valgus problems do you find it useful to mobilise the calcaneus? Also any other forms of manual therapy worth addressing before doing the arch strengthening exercises as decribed on youtube?

Also whens your professional presentation on shoes available and also any other ones beside the ones available on wannabefast. I bought all the ones available on wannabefast.

Thanks for your time,
D

Dear D

Appropriate physiological ROM’s are ALWAYS important prior to ANY rehabilitative procedure. So, if you are referring to any of the articulations with the calcaneus (talo-calcaneal (any or all of the 3) and calcaneio-cuboid), yes. The calcanueus needs to evert 4-6 degrees beginning at initial contact through midstance and pathomechanics here would limit subtalar pronation and reduce the shock absorbtion that these joints provide. This could result in a functional forefoot varus. Likewise, if there were no inversion, you would not be able to supinate and the foot would remain in an “unlocked”” position, being a poor lever arm.

It would be prudent to assure all ROM’s are within physiological ranges (or subluxation free) before proceeding with exercises.

Watch for our Show fit program, which is in the final editing stages. Stay tuned here or on our Facebook page for details.

The Gait Geeks

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The Perfect Forefoot Bipod

The ostrich is distinctive in its appearance, with a long neck and legs and the ability to run at maximum speeds of about 70 kilometres per hour (43 mph)^[3], the top land speed of any bird.

he bird has just two toes on each foot (most birds have four), with the nail on the larger, inner toe resembling a hoof. The outer toe has no nail.^[14] The reduced number of toes is an adaptation that appears to aid in running. Ostriches can run at over 70 kilometres per hour (43 mph) for up to 30 minutes. Although this bird cannot fly, it can run faster than the swiftest horse.their primary means of locomotion is running, so the feet have developed into feet fit for frequent, and very fast running especially to escape preditors. If it would keep on in a straight line no animal could overtake it; but it is sometimes so foolish as to run around in a circle, and then, after a long chase, it may perhaps be caught. A traveller speaking of the ostrich, says, “She sets off at a hard gallop; but she afterwards spreads her wings as if to catch the wind, and goes so rapidly that she seems not to touch the ground.” This explains what is meant by the verse, “When she lifteth up herself on high she scorneth the horse and his rider.”

It is a good thing that ostrich’s do not wear shoes. Over time their feet would have weakened and flattened and they would need orthotics.  Some animals are just smarter than humans.

:-)

In our ever popular; ask the Docs, here is another question from a reader

Transverse Arch

How would one go about “rebuilding” their transverse arch? The latter is pretty much convex. This also accomapnied by very tight long toe extensors (as evidenced by their tendons being very prominent at the top of my foot and my toes being curled at rest) and have suffered on and off from Morton’s neuroma. The ball of my shoes (right in the middle) is where the insoles of my shoes see the most wear. It’s not a huge concern of mine, but I would like to deal with this. I’ve suffered several ankle injuries (as a basketball player) and although I’ve tried orthotics in the past (for the neuroma), I’ve relied mostly on minimalist footwear (except when playing ball of course…). I know some rehab would be in order and would likely work. I’ve “reconditoned” my big toe abductors in the past and can even cross my second to over my big toe, so am just looking for some direction.

Thanks

E

 

Hi E

As you probably are aware, there are 3 arches in the foot: the medial longitudinal (the one most people refer to as the “arch”, the lateral longitudinal (on the outside of the foot) and transverse (across the met heads).

Your collapsed transverse arch seems like it may be compensated for by a rigid, probably high medial and lateral longitudinal arches. This creates rigidity through the midfoot (and often rear foot) and creates excessive motion to try and occur in the forefoot. Depending on how much motion is available, this may or may not occur.

You don’t seem to be able to get your 1st metatarsal head to the ground to form an adequate tripod, so you are trying, in succession, to get some of the other, more flexible ones there (thus the wear in the “ball” of the foot you noted). This results in increased pressure, metatarsal head pain, possibly a bunion and often neuromas.

From your description, you actually have very weak long toe extensors (and possibly some shortening) which is causing the prominence of the tendons, along with overactivity of the long flexors (and thus the clawing) in an attempt to create stability. I am willing to bet you have tight calves as well (especially medially, from overuse of the gastroc to control the foot) and limited hip extension with tight hip flexors.

The foot tripod exercises are a great place to start, as well as heel walking with the toes extended and walking with the toes up (emphasizing extension, which counteracts the flexors). Stay away from open back shoes and flip flops/sandals; continue to go barefoot and get some foot massages to loosen things up. Maybe use one of those golfballs to massage the bottom of the foot when you get off the course and get some golf shoes that aren’t quite so rigid.

Ivo and Shawn. Still middle aged. Still bald. Still good looking….

An entertaining song that sums up how we feel about feet.

Geez, we ARE geeks!

Have a great Weekend

Ivo and Shawn

The Importance of the foot function and posturing at terminal swing in a great and talented runner. Part 2 of the Toe Extensor Dialogue.

* This is a follow up from yesterday’s video blog post. Lets review once again and then dive in, layering some deeper principles onto yesterday’s dialogue.

Stand up. Both feet on the floor. Close your eyes and raise your toes up off the floor, just the toes, and then let them fall. Pay great attention to what happens to your arch height as you raise and lower the toes. Yes, do this now. Then come sit down again and read some more. Go !

Ok, now you are back.

Do you think that toe extension ability (range, skill, endurance AND STRENGTH) will play a significant part in achieving adequate successful arch height and thus treating plantar foot pain syndromes (plantar fascitis to name the most obvious and simple nemesis)? You better believe it, we showed it in yesterday’s blog post ! * For a great little video sample of a young boy with flat feet using our queue’s to restore tripod positioning and arch height along with a more normal foot progression angle, see yesterday’s blog post or click here.

So, if toe extension is critical for arch height, both in preparation for foot strike/contact and in arch height and control should you ever try to consciously limit this natural phenomenon ?

In the video above the author and runner (Jordan McGowan) at 1:07 discusses his concern that the left foot is coming across in too much toe extension (ie. ankle dorsiflexion as well) in preparation for contact phase and that his right foot is coming across less extended/dorsiflexed, something we sometimes call shallow dorsiflexion. He indicates that he likes the appearance of the right foot pre-contact approach but he feels that he wants to relax the toe up/dorsiflexion exaggeration on the left. We do not necessarily agree based on the principles discussed above and yesterday because arch height preparation will be reduced (again, see yesterday’s blog post and video). However, Jordan is not wrong either. Read on !

Now, although Jordan himself does not discuss any deeper concerns we could imagine that some less skilled runners in this scenario might worry that if the toe extension is too excessive that it will pre-position the foot for a heel strike phenomenon. This does seem very reasonable thinking, but it is not necessarily so. Heel strike is a conscious choice. If this is your concern, it can easily be overcome; you will just have to do one of two things to avoid heel strike (ie. get to mid foot strike, which Jordan does very well on both sides, even the left, despite its increased toe extension/ankle dorsiflexion).

To overcome the concerns of heel striking with high toe extension pre-contact:

1. One will have to lean forward more to offset the possible early heel strike. Leaning forward more (as is done in natural/chi running form) will make it harder to heel strike because the foot will land even further under the body. Whenever the foot reaches out in front, the opportunity for heel strike increases. Make no mistake however, there is a difference between heel strike and heel contact. A skilled walker or runner can heel contact and quickly transition to midfoot load and get the same effect as a more pure midfoot strike. The difference is whether you LOAD the heel contact or quickly transition to the midfoot. Any skilled runner can do this and feel this. When done skillfully, a mere kissing of the heel, a mere light brushing with the ground, before the midfoot loading occurs is completely fine just do not load the heel otherwise a deceleration event is going to occur and that is a definite “no no”. This is a problem with amateur gait analysts and runners, and proves once again that what you see is not always what you get. We demo this illusion all the time with our runners and without a skilled eye they cannot see the difference, but they can feel the difference when asked to focus on the skill difference. To reiterate, for MOST runners there should be little if any rearfoot loading response, it is a mere zone of transition. This topic is absolutely no comment here on Jordan, he has superb midfoot contact.

2. Back to overcoming heel loading……. one will also have to better eccentrically control the descent of the forefoot to the ground. This is a normal biomechanical event. Yes, you can reduce this need if you bring the foot through shallowly as Jordan explained regarding his right foot, but at the possible consequences of entering the pronation phase with a partially unprepared arch and subtalar joint configuration (if the subtalar joint is starting its loading at the mid or anterior facet joint pronatory unlocking of the midfoot will occur too soon). A runner with a highly competent and strong foot can get away with cheating this mechanical event, and it is quite (very) possible that Jordan has such a foot with all his running experience. On the other hand, a more amateur runner could be loading a bullet into the pronation gun. Now, back to the eccentric loading of the anterior compartment muscles. Too slow an ankle dorsiflexion posture release and the heel will strike first, too fast and the forefoot could slap on the ground. One will thus need to get the proverbial porridge just right (not too hot, not too cold…..rather just right). Most skilled runners will be able to get this skill down within just one workout and then master it over the next 12 weeks (the time we find necessary to engrain a new motor pattern in the cerebellum and parabrachial nucleus, the primary pattern generators). And with more skill and foot strength a more risky shallow posturing can be taken with success. And, this may very well be the case with Jordan. He may be there and be correct in his evaluation. We just wanted to share both sides.

Understanding the end-phase swing foot and toe function is important. Understanding what your foot is doing is paramount. We wanted to share both sides of the coin because we would hate for amateur runners to see this and try to reduce their proper and necessary toe extension/ankle dorsiflexion and mimic a shallow late swing phase foot posture. This is where running moves from science to an art. Guys like Jordan can play with this stuff safely, but not everyone else can or should. For many, better preparation of the foot for the contact phase in a solid tripod will reduce excessive and possibly deformative pronatory forces. Presenting the foot to the ground with a less than optimal arch, via a conscious reduction in toe extension, will increase risk for the deformative pronatory forces to have a better chance of creating tissue pathology (ie. plantar fascitis etc).

Here is one of the reasons we recommend even our elite runners from time to time to exaggerate the toe extension-ankle dorsiflexion range off and on during runs. If you never use the FULL range Tib Anterior and extensor digitorum longus muscles (as in the shallow end swing foot posturing), you will begin to lose their strength at the end ranges. We often lose end range strength first. And in time that can trickle down those weaknesses into the ranges where more of the strength is truly needed. This is the “gosh, my pain just started out of the blue phenomenon !” Truth is, it did not, you just finally found yourself without that necessary extra little bit necessary to adequately protect a joint for the load at hand. And perhaps this is the take home point here. We all need to be sure that we still have what is necessary for optimal joint complex protection from time to time. It is why many athletes come to see us a few weeks before big events, for assessment to be sure that they are not trickling down into that risk zone as they peak their training and then taper.

In another post, we will discuss Jordan’s frontal view issues. He wisely has detected his foot pronation issues and we couldn’t agree more about his mention of the gluteal control and an important factor. So we will once again review our Cross over gait pathologic movement pattern which is somewhat evident here and part of the foot posturing, but we will also discuss the abductory twist phenomenon of his left foot, which is truly what is going on at the foot level (don’t get us wrong, the glute is part of the deal, but it is not the entire deal).

From the start our mission has never been to strike at the moral fiber of someones good intent. Rather, our mission has always been to dispel the myths and state the facts. This was a great assessment by Jordan, we just wanted to point out a few possible misconceptions and explain some of the differences between a skilled runner and what they are working on and what an amateur runner should be aware of mainly so that the masses of runners who will see this great video will get the honest facts and not start to, or too early, consciously change normal behaviors and start to generate compensations.

We spoke to Jordan about this blog post before we ran it and he was a champion about it. It opened some productive dialogue on both ends, that’s the way it should always work. Jordan was all for stating the truth and facts from all angles.

We are Jordan and Newton fans. We thank Jordan for his input, his feedback and for sharing his nearly flawless running form in his Newton’s. This is a form everyone should take note of and try to strive for.

The Gait Guys

Shawn and Ivo

The foot tripod: the importance of the toe extensors in raising the arch.

* this is a two part series……. we have a great follow up video tomorrow that requires this video and blog post first.  So, wrap your head around these simple principles today and then we will apply them to a great runner and their video, tomorrow.

Stand up. Both feet on the floor. Close your eyes and raise your toes up off the floor, just the toes, and then let them fall. Pay great attention to what happens to your arch height as you raise and lower the toes. Yes, do this now. Then come sit down again and watch this video and read some more . Go !

What you should have noted, unless your foot is so flat and weak is that when you raise your toes off the floor (when standing or non-weight bearing actually) is that your arch should raise up. This lifting of the arch will improve your foot tripod ability (anchoring of the heads of the 1st and 5th metatarsal heads, with the heel at the 3rd point of the tripod) and it will shorten the longitudinal arch length. So, do you think that toe extension ability (range, skill, endurance AND STRENGTH) will play a significant part in treating plantar foot pain syndromes (plantar fascitis to name the most obvious and simple nemesis)? You better believe it ! Go ahead, prove us wrong.

In this video the young fella starts out with flat pes planus feet, increased foot progression angles (30 degree splay outwards) and excessive internal limb spin which is helping to drive the flat feet. 

For you clinical nerds, yes he could have external tibial torsion however, what you cannot see is that when we bring his feet back to neutral forward posturing and correct his arches his patella aligned forward and a squat test showed a pristine forward sagittal tracking.  Had it been a case of external tibial torsion, the knees would have been angled inwards and tracked medially, eventually knocking together. Again, this was not the case.

This was just a young boy with feet that had never learned the S.E.S (Skill, Endurance, Strength) of normal foot posture and intrinsic and extrinsic foot neuromuscular use.  Yes, we are once again harping on S.E.S.  It is critical that you get that SES concept down, in prior posts we have discussed the neurological logic to this progression via looking at nerve diameter/conductance. It is factual, not something we made up.

It took all of 1 week for this young man to gain this quick skill correction. On the  first visit we spent 20 minutes teaching him awareness of arch changes with toe extension use (the Windlass mechanism is engaged with Toe Extension) and awareness of the forefoot bipod contact points. We then followed that up with foot progression improvements to get his feel aligned better.  Soften the knee hyperextension that is frequent with pes planus and we were off to the races. Stage two for “Shuffle walks” was set, all he needed was this initial skill set, and you can see that in one week he had it nailed down to under a 1 second !!!!  Rock Star !!!  

He was now at our office to get the homework for the Endurance and Strength components. In this case, an orthotic had been attempted previously by other doctors but he still was not getting the skill set to find the corrected foot posturing on his own. Orthotics pre-position and offer a platform of correction to work off of, but you still have to earn the skill (unless you want to depend on orthotics for your whole life !).

We like the term Orthotic Therapy, meaning (when appropriate) use the device to help the process along when the client cannot find the pattern sufficiently.  It is clear in this case, this boy does not need the orthotic help he just needs the endurance and strength now that we have taught him the skill.  Sure, in basketball camp when he is focused on the ball the feet could use the help of an orthotic, but with the goal to earn his way from them in time. Some people with severe prontation control issues will always need the help. But our goal is to lessen the need and perhaps relegate the need to sports only. On the other hand, some people have such mild over-pronation issues, that this homework is sufficient to allow the orthotics to be tossed in the garbage.  Each case is different.

What is amusing is that in one week this boy practiced so hard and so much (as you can see) that he made me laugh at the end because it was clear he was already laying down the new skill pattern subconsicously, as noted by the fact that he was having troubles collapsing in the new tripod-neutral position.

Fixing flat feet. It is possible, not always , but often. You just have to know what your client has and what to do with it. Anyone can prescribe orthotics, be different, go the extra mile for your athletes and clients.

Start with working toe extensors and increase their awareness of what  happens with the arch when the toes go up and down. Teach them the tripod and then to integrate the two.  People will travel far and wide to find you if you master this stuff. We are honored that people fly in to see us from around the country. And when they see how simple a logical process can be, they wonder why they had to. But they are still happy they did.

Shawn and Ivo……. sometimes described as the fruit out on the far far branches (yes, maybe the ugly gnarly fruit) but we are still hanging tight to the branch none the less.   

Feel the Pain: Part 4: Pain Modulation

In previous posts, we reviewed the tissue producing the pain, the character of the pain, and how pain impulses travel from the periphery up to the brain. We should have called this post: Stop the Pain, since we will be talking about how what you do helps modulate the pain.

We recall that pain results from adequate activation of the nociceptive afferent system, the pain carrying sensory pathways. Most modulation occurs due to inhibition that attenuates activation. Think of it like a dimmer switch for a light. 

• your hand is the stimulus (or your foot if you are really talented, like Dr Allen)
• the dimmer is the receptor (in the case of pain it is a bare nerve ending)
• the wiring are the pathways from the periphery to the brain (path from the dimmer switch to fuse box)
• and the fuse box represents the brain
• the light going on represents pain
• and the dimmer represents pain modulation (lots of pain or less pain)

Are you with me so far? Are you smelling what we are stepping in?

How can we stop from turning the light on ?  We can never touch the switch. This represents good biomechanics; if we have good biomechanics, we are less likely to cause tissue damage and less likely to elicit pain because the receptor (the dimmer switch) was not stimulated, hence no turning on of the light.

What else? …  There is a possibility that we can turn the light on only a little. This is means we activate the receptor (the dimmer) only a little. This is what happens in the spinal cord. All primary afferents (sensory nerves from mechanoreceptors, muscle spindles and golgi tendon organs) activate an inhibitory interneuron in the spinal cord (see diagrams above) which presynaptically inhibits the the 2^nd neuron in the pain pathway (the pain neuron comes into the cord, synapses in the dorsal horn with a 2^nd neuron which travels up the cord to the reticular formation and parietal lobe of the brain, to let us experience pain).

Think about it. Good mechanics, massage, manipulation, and exercise all involve stimulating primary afferents (sensory nerves). They all inhibit the 2^nd order neuron in the pain pathway. They all affect the “adequate” part of the equation, making it more or less adequate, thus different degrees of pain are possible. 

Remember, that which travels up the spinal cord to the brain is the sum total of ALL MODALITIES acting on the 2^nd order pain neuron. MORE ACTIVATION = LESS PAIN.

Wow, is there more?  You bet! What if the wiring goes to a junction box to join other wires? This is what happens in both the spinal cord and thalamus; MORE MODULATION (Incidentally, ALL AFFERENT STIMULI EXCEPT SMELL pass through the thalamus). You mean vision and hearing can affect the perception of pain? Yes, remember it is an emotional response. Is it better to go to the dentist with the nice relaxing music, private rooms, soft colors and clean smells or is it better to have your dental work done in a prison camp?  There are visual, auditory and emotional components to pain.

The brain itself can modulate the perception of pain (think of people who are wounded in battle and never feel the pain) both at the level of the brain, AND by sending stimuli back down the cord to modulate it at the thalamus and spinal cord. Remember endorphins, your bodies own little heroin factory?

Wow, LOTS of things we do can modulate pain!

It makes shaking your hand after you whack it with a hammer (or your head after making it through this blog post) kind of make sense: that being, activating more peripheral receptors to modulate the pain. It is also what elicits a possible different emotional response when comparing being kicked high between the legs by your best friend while standing in a fresh spring meadow with birds chirping gleefully or by your worst enemy in a dark rainy alley during a thunderstorm (don’t believe us ? Give us a call, we are pleased to give free personal demonstrations). The environment, the mental settings, the smell, the sounds, your emotional standpoint, your overall pro-inflammatory health …… they all play into your pain and how it is interpreted, modulated and responded.

The Gait Guys. Modulating the learning process to make it easier for all to understand.

Ivo and Shawn…….. part-time, semi-pro punters. Give us a call on your way to divorce court or your next custody suit ….. our loving kicks will help modulate your true pain.

A Case for “Reverse Engineering”

You have often heard us say: “think of muscle function from a closed kinetic chain perspective”. In other words, the muscle(in the case of gait) working from the foot (or ground) up. Here is a study exemplifying this with the tibialis anterior and peroneus longus.

We remember the tibialis anterior is usually the most prominent muscle on the anterior leg (see 1st 2 pictures above). It has two origins, the lateral tibial condyle and the upper lateral surface of the tibia; it inserts on the medial surface of the 1st (medial) cuneiform and proximal part of base of the first metatarsal of the foot. It is a dorsiflexor and inverter of the foot in open chain (ie before and at heel strike/initial contact), and a dorsi flexor and inverter of the foot (or it brings the tibia medially and everts the foot relative to the tibia) from loading response to midstance. It also helps to maintain the medial longitudinal arch up to this point, and assist in decelerating pronation (along with its antagonist to dorsiflexion, the tibialis posterior). It takes a break at midstance and then contracts again at terminal stance (to counter act its antagonist, the peroneus longus). When running, it remains active through midstance to help pull the leg forward over the foot.

The authors have this to say: “Tibialis anterior restrained rearfoot plantarflexion from heel contact to 10% stance, and eversion between 10% stance and footflat.”

No surprises here.

Now the peroneus longus: “Activity in peroneus longus was consistent with its role in causing eversion after heel contact, then as a stabiliser of the forefoot after heel rise. ”

The peroneus (or fibularis) longus arises from the head and upper two-thirds of the lateral surface of the fibula, from the deep surface of the fascia, and from the intermuscular septa between it and the muscles on the front and back of the leg; occasionally also by a few fibers from the lateral condyle of the tibia.  You can see from it attachments that it can influence the entire upper lateral leg.

It’s tendon runs down the fibular shaft, wraps around the lateral malleolus, travels obliquely under the foot, crossing the lateral cubiod (which it everts after midstance to help with supination) crosses the sole of the foot obliquely, and inserts into the lateral side of the base of the first metatarsal and lateral aspect of the 1st cunieform.  

It acts from just prior to heel strike to limit excessive rearfoot inversion, through midstance to decelerate subtalar pronation and assists in stabilization of the midfoot articulations, and into terminal stance and pre swing to lock the lateral column of the foot for toe off and plantar flex the 1st ray (creating a good foot tripod), allowing dorsal posterior shift of the 1st metatarsal-phalangeal joint axis (necessary for dorsiflexion of the hallux (big toe)).

The peroneus brevis arises from the lower two-thirds of the lateral surface of the shaft of the fibua and from the intermuscular septa separating it from the adjacent muscles on the front and back of the leg. Again. lots of influence here.

It travels behind the lateral malleolus (and in front of the peroneus longus) and inserts into the tuberosity at the base of the fifth metatarsal.

It acts in a similar timeframe as the longus, copressing the tarsals to provide midfoot stabilization, and a significant eversion moment of the foot (helping to push you on to the base of the 1st metatarsal).

You can see how the peroneii could work together also to produce a small plantar flexion moment of the ankle and lateral movement of the lower leg. Because of their route around the lateral malleolus, they also can internally rotate the tibia (from a closed chain perspective; remember the tibia SHOULD be extenally rotation at this this point) so it can act to dampen or attenuate supination. This is also supported by the study:

“Activity in peroneus brevis suggested a role in restraining lateral rotation of the leg over the foot, late in stance.”

We are definitely the Uber Gait Nerds of the internet. We are bending your mind around the foot (rather than the foot around your mind).

Ivo and Shawn

Abstract

This study examined stance phase foot kinematics, kinetics and electromyographic (EMG) activity of extrinsic muscles of 18 healthy males. Three-dimensional kinematic and kinetic data were obtained via video analysis of surface markers and a force plate. Ankle joint moments are described about orthogonal axes in a segmental coordinate system. Kinematic data comprise rearfoot and forefoot motion, described about axes of a joint coordinate system, and medial longitudinal arch height. Surface EMG was obtained for tibialis anterior, soleus, gastocnemius medialis and lateralis, peroneus longus and peroneus brevis and extensor digitorum longus. It was concluded that the demands on the controlling muscles are greatest prior to foot flat and after heel rise. Tibialis anterior restrained rearfoot plantarflexion from heel contact to 10% stance, and eversion between 10% stance and footflat. Activity in peroneus longus was consistent with its role in causing eversion after heel contact, then as a stabiliser of the forefoot after heel rise. Activity in peroneus brevis suggested a role in restraining lateral rotation of the leg over the foot, late in stance.

http://www.ncbi.nlm.nih.gov/pubmed/11206820

Foot Ankle Int. 2001 Jan;22(1):31-41.

Extrinsic muscle activity, foot motion and ankle joint moments during the stance phase of walking.

Hunt AE, Smith RM, Torode M.

School of Physiotherapy, Faculty of Health Sciences, Lidcombe, NSW, Australia. a.hunt@cchs.usyd.edu.au

Erratum in

• Foot Ankle Int 2001 Jul;22(7):543.

A Scientific Look at High Heels

http://well.blogs.nytimes.com/2012/01/25/scientists-look-at-the-dangers-of-high-heels/

PROCEED WITH CAUTION! INFO DENSE POST AHEAD!

Can you think of a better way to start the week than with a discussion of high heels? We all like high heels… Well, at least guys do (and we know quite a few women who do as well…some of you may be reading this post). NO, WE DO NOT LIKE TO WEAR THEM, but we can admire the way they make the calves look so great and the increased lumbar lordosis and accentuation of the greatest gait muscles ever created!

Were they based off “chopines” from the 15th century; an elevated shoe (7-30 inches high!) which kept the peoples feet literally “out of the muck” (they didn’t have modern plumbing back then) or are they older? Or was the heel invented out of necessity to keep horse riders literally “in the saddle” ? Chinese and Turkish history says maybe they were to keep women (particularly concubines) from escaping. For the intents of discussion, we will stick with this last premise, as it fits nicely with the findings of this article (based on the study published here)

Remember the neuromechanics posts on muscle spindles or golgi tendon organs (GTO’s) ? If not, click the links and check them out; suffice it to say that the take home message is: Spindles respond to length and GTO’s respond to tension.

We also remember that GTO;’s modulate the muscles function that they come from. In other words, they literally “turn off” the muscle they come from (it is a disynaptic, post synaptic pathway for you neuro geeks out there). In light of that, lets look at some quotes form the article:

“the scientists found that heel wearers moved with shorter, more forceful strides than the control group, their feet perpetually in a flexed, toes-pointed position. This movement pattern continued even when the women kicked off their heels and walked barefoot. ”

No surprises here. Go up on your toes and take a few strides (more difficult for guys, since the biggest heel we may have is about 12mm in our running shoes). Which muscles are engaging? See how difficult it is to take a full stride? Try to engage your glutes. Not so easy, eh? Now put your foot flat on the floor, extend your toes and NOW engage your glutes. Easier? Presyanptic loading of the motor neuron pool pays big dividends!

They go on to say: “As a result, the fibers in their calf muscles had shortened and they put much greater mechanical strain on their calf muscles than the control group did.”

Hmmm… shortened muscles put under greater tension. Sounds like a job for the golgi’s, and what do they do? Inhibit the muscle from contracting. No wonder is was harder.

“In the control group, the women who rarely wore heels, walking primarily involved stretching and stressing their tendons, especially the Achilles tendon. But in the heel wearers, the walking mostly engaged their muscles.”

Wow, here is evidence They changed their motor programming!  Did you ever think that high heels could change the way our brain works? Maybe it’s a secret plot to take over the world….or maybe not…

The Gait Guys…Lovers of high heels as long as you don’t walk in them….

Athlete with Plantar Fascitis

Gentlemen,
 
I have enjoyed your blog tremendously.  My inner mechanics geek motivated me to read all the blog posts, and go through the Youtube videos as well.  Fascinating stuff.
 
My reason for writing, however is more desperate.
 
I have an athlete with a problem, and hope you might provide some guidance.  She is experiencing what has been diagnosed as plantar fasciitis, with her pain on the medial side of her calcaneus - roughly 2 inches forward of her achilles, and about a half inch up.  MRI was negative for a calcaneal fracture.   She’s taken several months off, and had the site injected, but any return to running brings her pain back.  It’s her mechanics that might catch your interest;  she has what a doctor once referred to as ‘an Equinus Deformity", essentially running completely on her forefoot.  She had heel contact when walking, but is completely on the balls of her feet when racing or training.  Her injury history to this point has been minimal, with only a minor adductor issue for a day or two in her background.  She has been told her options are injection (tried, helps for only a short time) or surgery.  Humbly, is there anything we can do to help her overcome this?  I am convinced there is an underlying mechanical issue, but her somewhat nontraditional running style leaves me with few ideas.  Any suggestions would be worth their weight in gold.  
 
 
Sincerely,
  
Girls XC/track coach
 

Dear Track Coach

Thank you for the Kudos and we are glad you have an “inner mechanics” geek as well .

We are sorry to hear about your athletes recalcitrant problem. It was astute observation on your part regarding her gait. Given the history you have provided, what has already been done, and the description of what you see, please understand that our opinion is limited, without the opportunity to examine her (which we would be glad to do; we have offices in the Chicago, IL suburbs and West of Denver, CO). Video would be helpful in the future as well, as we are not sure she has a true talipes equino varus foot or it is merely describing the attitude of the foot while running.

It sounds like she may have a rigid foot and a forefoot varus deformity. This would parlay with the “equinis” description.

A forefoot varus is when the forefoot to rearfoot relationship is such that the forefoot is inverted with respect to the rearfoot. This causes increased torque on the plantar fascia, as the forefoot lands on the outside of the foot and the medial side of the foot immediately descends: this must be controlled some how: either through flexion (downward motion) of the 1st metatarsal and cunieform (ie 1st Ray complex) provided adequate range of motion is available; the other scenario is that there IS NOT adequate range of motion of the 1st ray available and the knee collapses medially to bring the 1st ray down to the ground. A third possibility (most likely) is that it is a combination of the two.

The fix lies in the etiology: follow the mantra: skill, endurance, strength. Insuring the foot has adequate range of motion and is able to control it (skill), the appropriate endurance of the muscles to carry out the job (endurance) and the foot intrinsics have the cross sectional area needed to do the job (strength).

1. Does the athlete have a adequate foot tripod and are they able to keep all 3 legs of the tripod on the ground with the knee comfortably over the 2nd metatarsal? see a video here

2. does the athlete have enough muscular control of the lower extremity to ensure proper mechanics (foot intrinsics, knee motion, hip motion) ?

3. Is their running gait appropriate for their anatomy and any physical limitations? we have numerous posts covering many different gait scenarios on the blog, as well as on our youtube channel.

Again, without an exam, pictures or video, the exact diagnosis and fix is difficult. Thanks for the opportunity to respond.

The Gait Guys

It has been a year, but this video is still as important as it ever was. Now that we have many of new viewers, perhaps they missed this one. It is always good to review. Enjoy !

News about Our blog.

Are you following us on our FACEBOOK page ?

every day we try to add extra stuff that will broaden the info, for example, today we added some extra info onto Facebook regarding muscular infarts such as what House has. 

If you are not a daily follower of our Facebook page you are missing out on a little extra info. 

Just sayin ……

here is the link……. go ahead…….. click the LIKE button…… WE DARE YA !

http://www.facebook.com/pages/The-Gait-Guys/169366033103080

House MD. :  Is he using his cane on the correct side ?

This is a great video clip (when you click on the youtube link it  might not work. Try clicking here ……go ahead and click that link to watch and then come back. Note to listeners…. there is controversy over the lyrics, there always has been and always will be …..but they are listed below at the end of the post.)

When can you ever go wrong with AC/DC ? Combine that with Hugh Laurie from HOUSE MD and you have a great mix.

So, watching this video, why is he using his cane incorrectly?  We all know that House’s has a problem with the right hip and leg.  “The Rules” state that with a hip problem the cane should always be used on the opposite side to change the D2 lever arm (Click here for a great lesson on this) with a nice follow up here (click). After watching these 2 Gait Guys videos you will clearly understand (perhaps to a better level than most of your therapists and doctors who gave you the cane) why it is used on the opposite side.

So, why in the world is the brilliant Dr. House using it on the same side ?  We have received this question more than once.  And the answer is quite simple.  His problem is extracapsular. In the pilot episode of House MD it was explained that he suffered a vascular infarct to the quadriceps muscle.  Like bone infarcts, muscular infarcts can be painful. If he contracts the quadriceps when loading the leg there will be pain.  Just like if the infarct were osseous,  the loading of the cortical bone and stress on the trabecular infrastructure in that case, axial loading of the limb (muscular or osseous) will drive pain. So, to lessen the issue he uses the cane on the same side to literally share his body mass load over the length of the cane.  He is essentially attempting to use the cane as his weight bearing limb.  The cane use on the opposite side is best used when you are attempting to unload the muscular compressive forces across the hip (acetabulofemoral) joint.  Contraction of the gluteus medius generates the greatest joint compressive loading of all of the hip muscles because of its orientation during gait. Thus, utilizing the cane on the opposite side acts as a hydraulic lift necessitating a shift in body mass closer to the joint and reducing the compressive demands on the gluteus medius muscle. 

* Rule breaker: sure, you can still use the cane on the same side to reduce the gluteus medius forces, it is just a bit more awkward.  But it can be done.  Think about and elderly folk who had a weaker opposite arm, they would feel more comfortable using House’s strategy. The rules are not hard pressed. 

So, House is using the cane correctly for his condition. 

Rules are meant to be broken.  Look at our leaders (all parties) in Washington, they do it everyday ! And when you are as smart as House you know when to break the rules. 

Thanks for the reminder AC/DC ……lyrics

“Living easy, living free

Season ticket on a one-way ride

Hey Momma, look at me

I’m on my way to the promised land.

Asking nothing, leave me be

Taking everything in my stride

Dont need reason, dont need rhyme

Aint nothing I’d rather do”

Shawn and Ivo……….. or maybe it is Beavis & Butthead ?

(uh, that’s cool dude !  huhhh huhhhhh …… Those Gait Guys Rule…… !!!! )

The Truth about treadmills. Our Triathlete magazine article finds its way to the TRi website.→

Regarding our treadmill article in Triathlete magazine.
Most things in this world have a place, a function, an advantage and a disadvantage. It is the wise and informed that can extract what they need from a device to serve its purpose. Knives are useful but you can also cut yourself with them if you do not know what you are doing…..that doesnt mean you empty your knife drawer at the side of the road on garbage day ! Keep on running. - The Gait Guys

chase the article through the linked above

Well, with the Barefoot Running Craze, and all the misinformation out there, we thought you would appreciate this short video

Have a great Friday…

Ivo and Shawn

Anterior knee pain in a young marathon hopeful, someday !

Here we see three (3) pictures of a very young boy, 4 years old. His mother brought him into our office for evaluation. His knees were painful immediately below the patellae bilaterally.

As you can see here the little fella has a few issues, some of which he will likely grow out of and some of which he may not. So this is a good case to follow.  First time parents are always  more vigilant and that is why we like them, but just fractionally more ! In the view from behind you need to see a few things:

1. valgus knees
2. wider than normal base of stance between the feet
3. slightly valgus ankles
4. and on the side frontal view……. obvious hyperextension of the knees and increased ankle plantarflexion posturing (we chose that word carefully) that obviously goes hand in hand with this retro-postured knees.

After a few more questions it was clear that the pain  had been around for quite some time and was at a specific pencil eraser sized area above the anterior joint line, slightly medially to center and without question not at the joint line proper but directly on the medial femoral condyle.  So, do you know what he has ?  You should always suspect this in knees that hyperextend this far or in athlete that have sustained or repetitive hyperextension stressing:

• gymnastics
• kicking sports (martial arts, soccer, swimming etc)
• postural syndrome folks (like this little fella) who have low core tone, anterior pelvic tilt both of which drive knee hyperextension. 
• any one who has a loss of ankle rocker dorsiflexion range and who then chooses the knee hyperextension option to regain ankle range in an attempt to normalize progressive gait. Frequently flatter feet/hyperpronators will drive more tibial internal spin resulting in hyperextension as well.

This little fella has the last 2 factors, BIG TIME !

So, clearly understanding these biomechanical factors and coupling a palpatory tenderness at the correct spot on the medial femoral condyle indicates that he has (the youngest we have ever seen)…….drum roll…….

Anterior meniscofemoral impingement syndrome.  Never heard of it ? Probably not. Why, because it was glazed over in school, and maybe not at all for many doctors to be honest. Go ahead, look it up under Pubmed and see how many referenced papers you find on it.  We see it enough to know that it is frequently diagnosed as a patellar tracking problem but those clients do not have the same risk and anatomy factors. We have had our doctor referrals call us back saying they have never even heard of it.  Most have not to be honest.  Bottom line, if you know your anatomy and your biomechanics you can figure out most things. If you are slim and skinny on either one you might be missing a few things.  We do sometimes as well.

Summary:  When the knee hyperextends either too much, too long, or for too many repetitions either statically or in dynamic walking, running or in activity the leading upper edge of the medial meniscus (see anatomy diagram above) can impinge repeatedly and forcefully into the soft medial femoral articular cartilage (see the colored purple area in the diagram) and over time create a softening of the cartilage (condromalacia as it is known).  Do it long enough or enough times and you create an inflammatory reaction with a cartilagenous defect.

This poor little guy was hating walking.  Interestingly, what do you think happened when we had him crouch walk (knees flexed)……yup…..no pain. He looked up at me in wonderment immediately and of course saw us smiling knowing very well he would be pain free. 

Solution in a 4 year old.  Slightly flex the knees and place a long strip of tape down the back side of the upper and lower leg.  If he extends the knee he forces the tape taught and is instantly reminded (pseudo biofeedback if you will) that he is approaching the danger zone. As this case and many other find, after a few days the skin gets pretty irritated but that is time to take the tape off and let him go back to his old tricks……. trust us, it is only for a few hours until he will figure it out……meaning….. hyperextension is evil ! Teaching this little guy our now famous “Shuffle walks” (to drive ankle dorsiflexion strength in the tibialis anterior and toe extensors in a posture of knee flexion) was on the menu and we turned it into a fun game for him to play with mom and dad.

Anterior Meniscofemoral Impingement Syndrome.  Say it 3 times fast with a mouthful of organic chunky peanut butter. We dare ya !  (Sounds like a whimpy frat house hazing technique if you as me.)

Hope you never see it in a little one. if you do, smile and reach for some tape and put on some 70’s music and shuffle to some oldies.

Shawn and Ivo……. yup, orthopedics is also in our soup of letters after our names. But it ain’t the letters that matter, it is what you do with them. Anyone up for Scrabble ?

* Oh, look, we found one  journal article ……from 1996 ! Sad.

Arthroscopy. 1996 Dec;12(6):675-9.

Meniscal impingement syndrome.

McGuire DA, Barber FA, Hendricks SD.

Source

Plano Orthopedic and Sports Medicine Center, Texas, USA.

Abstract

The meniscal impingement syndrome consists of three elements: impaction on the anterior medial femoral condyle by the leading edge of the medial meniscus, articular cartilage damage of at least Outerbridge grade 3, and knee hyperextension of at least 5 degrees. This report reviews this condition in a series of seven knees with an average follow-up of 39 months. The time from the onset of symptoms until surgery averaged 45 months. Treatment consisted of a thorough arthroscopic knee evaluation and debridement of the articular cartilage fragmentation and any impinging synovitis. Postoperative rehabilitation includes extension block bracing, hamstring strengthening, and closed-chain exercise. With this regimen, there was improvement in the Tegner scores and a reduction in postoperative knee hyperextension. Identification of this uncommon condition requires a complete evaluation of the medial femoral condyle in patients with knee hyperextension.

________

Neuromechanics Weekly: Third Installment

FEEL THE PAIN: PART 3

The Pain Pathway

Pain is the emotional response to adequate activation of the nociceptive afferent system.

What?

Pain is an emotional response. We feel (or experience) it in the cingulate gyrus (the gyrus right above the corpus callosum, that thing they cut in “One Flew Over the Cukoo’s Nest, see the 1st picture above). Your pain is different than your patients/clients pain. Like John Travolta said in Swordfish "It’s all about perception…”

Pain is subjective. Men usually have lower tolerance for physical pain than women (We think this has to do with their wiring, as it is all connected for them, and we males have our little boxes we keep everything in (see here if you don’t understand).

We know what “adequate activation” is. Enough stimulus to elicit a response. Like when someone keeps pestering you and finally you let them have it!

The “nociceptive afferent system” is the pain pathway. You remember: the C fibers (or pain fibers) in the periphery get activated (adequately, of course), the impulse travels up the peripheral nerve to the dorsal horn of the spinal cord, synapses in lamina 2-5 (the key here is that it synapses; proprioceptive and other sensory stimuli DO NOT synapse, but travel higher up the chain. The synapse allows modulation of the signal, the subject for the next in this series’s post). The next neuron in the pathway (remember, we are still in the cord, right after the 1st synapse) crosses (or decussates) the cord and travels up the ever famous lateral spinothalamic pathway (see middle picture above). We would think this pathway (from the name) goes an synapses at the thalamus next (THE central relay for ALL sensory stimuli EXCEPT SMELL); in reality only about 27% of the fibers synapse here, and then go to the parietal lobe. to tell you WHERE the pain is.

What about the other 73%? They go to the reticular formation ( a loosely organized group of nuclei in the brainstem) to cause the autonomic concomitants of pain (increased heart rate, increased breathing, nausea, urge to urinate, etc).

So, the next time someone has pain in their knee or foot, or _______, not only will you be able to tell what tissue is causing the pain, but now can trace the pathway north to the brain. Why is this important? Because of the modulation that YOU can influence with your therapy. More on that in  the next neuromechanics.

The Gait Guys. Eliciting a response in your cingulate gyrus. Hopefully, you are storing this in your inferior temporal gyrus (memory area) for future use.

When the knee hinges sideways. A clinical video case.

This is not a difficult case today, not by any means. Most people will can see what is not normal  here. But there are some simple principles we wanted to highlight and remind you of that this case shows nicely.

This is a fairly typical advanced degenerative arthritic right knee and the gait that accompanies it.

Here you can see that when the gentleman steps onto the right limb the knee has a small lateral hinge moment, you can see the knee joint buckle sideways.  This is not normal, the knee is supposed to hinge only forward and backwards (flexion and extension) in the sagittal plane.  Here it is hinging in the frontal plane. You can easily see that after many years of abnormal stresses that the tibia has deformed into a varus bowed position.  This is a great example for you engineer-type out there about long term deformation of solids.

* Deformation of Solids:

• Stress: is a measure of the force required to cause a particular deformation.
• Strain: is a measure of the degree of deformation.
• Elastic Modulus: the ratio of stress to strain:

                  Elastic modulus = Stress divided by Strain    or 

                                     EM= Stress / Strain

The lateral forces and hinging over time forced the tibial to varus bow which is a reactionary measure. In simplest of terms, as the bone cells (osteoclasts and osteoblasts) continued to cyclically turn over they laid down new osseous structure along lines of stress which happen to be in the frontal plane, hence the frontal plane bow. At the joint line it was simple to feel and advanced gapping and shifting of the joint in medial-lateral-medial stressing. One can only imagine the maceration of the cartilagenous menisci in such a knee from the abnormal shear forces. Oy !

In this gait, this joint is quite clearly painful as evidenced by the pronounced limp.  As right limb weight bearing is initiated carefully and slowly to reduce pain and gain stable purchase of the limb with balance the lateral shift is seen to occur.  This lateral shift challenges all of the frontal plane stabilizers so it should be no surprise to anyone that he has significiant gluteus medius, peroneal and abdominal weaknesses in guarding that right frontal plane (to name just a few). 

It is most difficult to see on this video because of the loss of 3D specs and because we do not have a frontal view of this gait, but what you typically see in the gait of these clients is a normal left to right step length and an abbreviated right to left.  As the brain loads that right limb there is pain and instability sensed by joint and pain receptors. This sparks an early and abrupt departure off of the right limb and hence an abbreviated and shortened right to left step length. This will impart a quick load onto the left leg with an abrupt loading into the left quadriceps. It is not uncommon at all for these clients to develop anterior knee pain syndromes (such as patellofemoral tracking syndromes) or foot problems because of repeated abrupt mid-forefoot loading which drives significant of calf-posterior compartment loading (this will also drive long toe flexor strategies). Also, an abrupt right to left weight bearing shift will generate excessive left lateral (frontal plane) forces thus it is not uncommon to show or develop left hip issues or to see more sustained supination of the left foot.  The Peronei can be challenged too to fend off this over-supination that can frequently occur.

* clinical pearl: In our clinics when we see a one sided increase in toe clench and long flexor tone, even when the client lies down, we will once again review gait and look and test for clinical instabilities of stance phase mechanics on the OPPOSITE side of the long toe flexor evidence (in this case there was increased left long toe flexor evidence and early hammer toe formation). This is a huge key, we  have just sold a few acres of the farm giving away this pearl. This is one of our goto tricks to find deeper embedded clinical problems. It is not always the case, because the long flexor problem can be local or same sided but you have to at least consider the thought we have proposed.

This is the exact same gait pattern as in a sprained ankle, in fact, same pattern when any part of a limb is painful.  As you leave the healthy left foot the brain already knows that right foot impact is going to be painful so a pre-calculation is make to soften the loading and to reduce the loading time, hence the premature limp off the right and onto the left. 

It is also important in these cases of significant unilateral bow/varum of the tibia to investigate whether a true leg length discrepancy has developed. It can be a part of the visual limping/lurching gait but it is part of the deformation of the tibia.  In this case we ended up using a 3mm sole lift (don’t use a heel lift, why would you just raise the heel ?) to level out his pelvis to decrease the frequent low back pain and tightness that goes with such a gait and also to reduce the step-down drop onto that degenerative knee. In this case, the lift reduced the degree and rate of lateral hinge and thus reduced much of his pain and back discomfort. By bringing the ground up to his foot he thus did not have to step down onto the right limb which accelerates the lateral shift.

* Try it yourself, find a curb on your street and walk along the top surface of the curb with the left foot, stepping down onto the right foot to street level.  Do this for a year and you would quickly appreciate what this gentleman was experiencing daily……to a degree of course. The lift on the right would be warmly welcomed !

We were actually able to keep the client very comfortable for almost a year which got him to a time frame that worked for his work and vacation time frame to have the surgery. This is often what a client needs, time. Just time to plan, to prepare mentally for a TKA (Total Knee Arthroplasty (replacement)).

The laterally hinging knee.  It is so much more than just a degenerative joint. There is much to be appreciated and learned from pathologic gait patterns.

We are…… Shawn and Ivo…… The Gait Guys ……. center focused but considered by many to be a little off plumb.