Yesterday’s Video Case: The Gaits of Hell

We have received many emails on this case already. Overwhelmingly people are saying……. “Hey, this isn’t easy….. It’s easy when you guys tell us right away because we can see it."  
Yes, when we are all alone to solve these gait problems our heads can start to swim with all the variables. Gait analysis is not easy.  Even the video assessment computer programs do not give you the answers and diagnosis, they just give you variables and data.  The thinking still has to be  done at the end of the day.

I remember how much I struggled with this case back during my orthopedics residency. I remember even pulling out my undergrad notes from Univ. of Waterloo as a student of the famous Dr Stewart McGill and mapping out FBD’s (Force-Body Diagrams) on this case. Oh, the horror !!!  I still have occasional FBD nightmares, being asked to solve an equation in front of the whole class. Pure anxiety ! Holy night terrors ! But, it is amazing what a few decades of study will do for you, we can now look at this case and see things for what they are, see them quickly and know what is going on almost immediately.  It takes some time, so if you are new to this stuff, be patient…… it will come.

CASE REVIEW:

in this video we see the following:

1. large step length off of the left foot abruptly onto the right, this step is sudden and he crashes down on to the right foot sooner than he normally would to catch his forward moving body mass. ( this will make more sense after reading #5).
2. there is a delayed left heel rise and delayed left calf recruitment , actually, it’s not delayed, it’s absent. )
3. the left foot remains supinated through the entire gait cycle. 
4. the left foot shows extraordinary long toe flexor recruitment (seen on the end of the video during the foot close up)…….this point is important
5. pelvic unleveling is apparent but a mirage for the most part. We really do not see a true Trendelenberg style gait (although it sort of looks like the left hip drops) rather, what you see is the result of the manufactured delayed left limb departure and subsequent impact at right limb load … but this is not a Trendelenberg gait, he had no Gluteus medius weakness.  Explained another way, he is having troubles departing off of the left foot (this diagnosis is the reason, he has compensated from a neurologic lesion affecting the strength of the calf) and so he extends ( behind him) the left leg longer and further than normal because he cannot push off, plus he hyperextends the left knee because of these factors. Normally, the calf fires after passive heel lift occurs. But with a lesion affecting the calf it has arrested the push off. So, in his case, the heel stays on the ground until it is dragged off from enough  forward body carriage. So, when you see this from a sagittal view the left hip will look like it is dipping as it does here, but it is not truly, he is just taking a long lurching step off of the left and onto the right, the longer left hip extension behind him sets up the illusion of a left hip drop.  Try this at home to feel this gait, walk down your hallway and try to delay the left heel rise for as long as you can.  You will find that you get into your left gluteals more, take a longer step on the left, and take a sudden lurching load onto the right limb to catch your forward progressing body mass. This is exactly what this chap is doing.  But why ? The left calf lesion. 
6. continuing on #5, there is abrupt right frontal plane loading (because of the sudden transition from left foot to right the frontal plane is engaged longer than normal) and thus the pelvis is carried further to the right in the frontal plane.  He makes a  noble attempt to protect this range by turning out the right foot into the frontal plane (aka. increased right foot progression angle) to allow the quadricep muscles to assist the gluteus medius, abdominal obliques and lateral limb stabiliers in decelerating this frontal plane challenge.

Diagnosis:This doctor came to see me while I was completing my orthopedics residency and mid way through my course work in the neurology post doctoral program. He had been treated for mechanical low back pain with failed results ( well, to be accurate. his low back pain had resolved but pain had peripheralized into the left leg. To review, peripheralizing pain is rarely a good neurologic sign.)  After an examination showing an absent left S1 Achilles reflex it was highly suspicious we were dealing with a radiculopathy. An MRI confirmed a substantial left foraminal disc herniation obliterating the left S1 nerve root foraminally. The S1 nerve root expands into branches feeding input into the lower limb muscles.  In this case, the unfortunate group affected was the gastrocnemius almost exclusively. So in this case this makes sense to what is presented clinically and on gait evaluation. He is overutilizing his long toe flexors (fortunately untouched) as seen in the video because they are basically all that is available to him to plantarflex the foot ( create heel rise and push off).  They are certainly not well suited for this task but subconsciously the brain will use what is available to it, worthy or not. In this case they are a feeble attempt at best. There is no way the long toe flexors can lift his body mass into heel rise and propulse it forward, they are synergists of this task and not agonists / prime movers.
Sequencing Summary:So, this is a case of an aberrant or pathological gait pattern that will be permanent because the nerve damage was fixed by the time i had seen him.  Muscular wasting of the gastroc complex had already occurred.  The culprit was the space occupying lesion (disc in this case) in the left spinal vertebral foramina effacing and deforming the nerve root sufficient enough to create dennervation.  A surgical consult and EMG/NCV (as best as i can recall) confirmed this case was non-surgical at that time (no one wanted to touch the case).  The nerve damage disabled the calf so that push off was impaired.  He thus delays his ability to create adequate heel rise and propulsion so the long toe flexors are called to attempt the feat.  The foot supinates to maintain its rigidity ( it is also hard to pronate through the foot when the toe flexors are in an all out contraction). And because the heel does not rise on its own from muscular strategies, the foot waits to be lifted off of the ground by simple forward progression of the body.  This creates an increased left hip extension range and gives the appearance of a left hip drop which is a false appearance pseudo-Trendelenberg sign.  Due to the fact that he is on the left limb longer, he will be on the right limb for a shorter period.  This right stance phase is initiated abruptly as he falls from the delayed left stance phase. The abruptness of the load on the right challenges the right frontal plane as evidenced by the right foot turn out and right pelvis sway (subtle).  He then departs off the right to  begin the cycle once again.
PS: It is coming a little late, but thank you Dr McGill. Your teachings to a young undergrad set my biomechanical thinking on the right path very early in my studies of human kinetics. Thank you, Sincerely. 
Dr Shawn Allen…… The other half of The Gait Guys