Gait Problem: The solitary externally rotated foot, or “why is my one foot turned out ?”
In a previous post (and on the Cross Over video and hip biomechanics video) we talked about the externally rotated limb/foot as a compensation for a same sided weak gluteus medius. You should recall that in the scenario of a weak gluteus medius, a wonderful frontal plane stabilizer, the foot can turn out to help better engage and protect that frontal plane cheat or compensation by drawing the quadriceps availability into play in that frontal plane. By turning out the foot the knee hinge range goes with the foot and so the quadriceps can now actually help to engage and protect motion into this frontal plane. We call the foot turn out in this scenario, “the kickstand effect”, like a kickstand on your bike, it flips out to add stability in another plane. This is a nice compensation, one seen often, but it has its own set of sequelae such as patellar tracking syndrome, IT band syndrome, trochanteric bursitis and foot pronation challenges to name just a few.
However, there are other reasons for the externally rotated solitary foot. Lets look at another cause.
* Limited internal hip rotation range will be the topic today.
In order to pass through the midstance phase of gait, in walking or running, the hip must internally rotate at least 4-6 degrees. Actually, to be perfectly accurate, since the hip is the fixed part (foot is fixed on the ground) the acetabulum socket of the pelvis which sits upon the hip’s femoral head, must be able to externally rotate those 4-6 degrees on the femoral head in order to get the subsequent full, timely and optimal hip extension and gluteus maximus contraction. So, what we are saying is that the pelvis which is sitting upon the hip’s femoral head must be able to oscillate to accommodate the swing phase of the opposite leg. For example, if the right foot is on the ground the pelvis is going to rotate clockwise upon that right femoral head which has been brought on by the left leg forward swing phase of gait.
Now, if that right hip joint does not have adequate internal rotation, the clockwise spin of the pelvis on the femur head will hit an early limitation end range. We will talk about the consequences in a moment but first we need to remind you of things we have talked about in previous blog posts: when we limit internal hip rotation the degree of hip extension will also be limited. You need sufficient internal rotation at the hip to get the subsequent hip extension and resultant gluteus maximus optimization.
Now, back to the possibilities when the pelvis cannot rotate clockwise enough on the right femoral head (ie. internal hip rotation). A few things can happen as the limitation is reached:
- the left foot (swing limb) can drop to the ground prematurely rendering a short step length
- the pelvis rotation on the hip will hit capsular close packing and compression and come to a halt but the forward momentum of the body-pelvis swing will cause an external rotation pivot of the foot and this extra spin from the foot will achieve the last needed pelvic motion (we call this “cigarette foot”, like putting out a cigarette under the ball of your shoe). Interesting note for those of you who run on crushed gravel or other forgiving surfaces, pay attention to this subtle spin on these surfaces, this could be the spin that you feel at toe off. This is sort of like the Abductory twist of the foot phenomenon, however that is a typically reserved term more for an excessively pronated foot.
- the individual will simply limit their stride length to avoid the above problem range however they will also be limiting hip extension, weakening the gluteus maximus. Premature heel rise will go with this issue (seen beautifully in this video above).
- Since internal rotation is a precursory range before hip extension, if you limit internal rotation you will limit hip extension. When hip extension is limited quite often you will ask for more saggital extension from the joint complex above or below the hip, so looking above the hip we can see increased lumbar extension or below we can see knee hyperextension, both compensation can make up for the loss of hip extension.
- As the internal limitation is met, pelvic obliquity can be adopted to normalize linear saggital gait progression. Eventually the core will become asymmetrical and create a pelvic obliquity distortion pattern which can be seen on static standing, typically a clockwise pattern (if we are talking about the right hip limitation) to enable more of the internal rotation at the hip (re-read #1 to understand this).
- And finally, the easiest of the patterns, the brain sometimes will sense this aberrant pattern and simply turn the right leg-foot outwards into external rotation. Why ? Because, when you move through midstance and hit the internal hip rotation limitation a compensation must be met as described above. If from the start of the gait cycle you merely set the foot progression angle into external rotation (as in the video above), the pattern (albeit dysfunctional) gets to groove the aberrant pattern more smoothly. At the severe cost of weakening the internal limb rotator muscles and gluteus maximus (sacral and coccygeal divisions to be specific) and perhaps even more detrimental losing the advantages of proper toe off of a rigid foot (again, look at the arch collapse, toe hammering and premature heel rise in the video above, there is a price to pay for compensating). In this scenario, you are literally creating the hip range of motion (by externally rotating the limb) that you didn’t have.
Of course the best solution is just to figure out why the internal hip rotation is limited (address both tightness in soft tissues and the weaknesses that drove that protective tightness, yes stretching rarely solves the world’s problems). Then regain symmetry, and the optimal and efficient motor patterns.
And of course, there are neurological sequelae occur as a result of this strategy, but that is the subject of another post on another day.
The externally rotated foot is an adaptive strategy. It is biomechanically brilliant, but fraught with compensations and prostitution of far reaching motor patterns (yes, this pattern will often effect normal arm swing in the contralateral limb, see our arm swing blog posts from last week). Simply telling someone to turn the foot back to forward facing neutral (5-15degrees progression angle) is not the solution. Gosh, if it was that easy doctors like us would also have long tails and be seen swinging from trees eating bananas.
The externally rotated foot. There is more to it than meets the eye. Dig deeper and you will find the answer, if you do not mind some heavy thinking.
Shawn & Ivo, The Gait Guys ……. Rubix’s cube kind of guys.