Exploring the Links Between Human Movement, Biomechanics & Gait
Why does this gal have so much limited external rotation of her legs?
We have discussed torsions and versions here on the blog many times before. We rarely see femoral antetorsion. She came in to see us with the pain following a total hip replacement on the right.
Note that she has fairly good internal rotation of the hips bilaterally but limited external rotation. This is usually not the case, as most folks lose internal rotation. We need 4 to 6° internal and external rotation to walk normally. This poor gal has very little external rotation available to her.
Have you figured out what’s going on with hips yet? She has a condition called femoral ante torsion. This means that the angle of the femoral neck is in excess of 12°. This will allow her to have a lot of internal rotation but very little external rotation. She will need to either “create” or “borrow” her requisite external rotation from somewhere. In this case she decreases her progression of gait (intoed), and borrows the remainder from her lumbar spine.
So what do we do? We attempt to create more external rotation. We are accomplishing this with exercises that emphasize external rotation, acupuncture/needling of the hip capsule and musculature which would promote external rotation (posterior fibers of gluteus medius, gluteus maximus, vastus medialis, biceps femoris). A few degrees can go a very long way as they have in this patient.
confused? Did you miss our awesome post on femoral torsions: click here to learn more.
Hmmm. We are fully internally rotating this gentleman’s lower leg (and thus hip) on each side. What can you tell us?
Look at the upper picture. Does the knee go past midline? NO! So we have limnited internal rotation of the hip. What are the possible causes?
femoral retro torsion
tight posterior capsule of hip
OA of hip
tight gluteal group (max or posterior fibers of medius)
Now line up the tibial tuberosity and the foot. What do you see? The foot is externally rotated with respect to the leg. What are the possible causes?
external tibial torsion
fracture/derangement causing this position
Now look at the bottom picture. Awesome forearm and nice choice of watch. Good thing we didn’t wear Mickey Mouse!
Look at upper leg. Hmm. Same story as the right side.
Look at the lower leg and line up the tibial tuberosity and the foot. What do you see? The foot is internally rotated with respect to the leg. What are the possible causes?
internal tibial torsion
fracture/derangement causing this position
So this individual will have very different lower leg mechanics on the right side compared to the left (external torsion right, internal left). We refere to this as “windswept” biomechanics, as it looks like the wind came in from the right and “swept” the feet together to the left.
What will this look like? Most likely increased pronation on the right and supination on the left. What may we see?
calcaneal (rearfoot) valgus on right
calcaneal (rearfoot) varum on the left
bilateral knee fall to midline
knee fall to midline on right occurring smoother than on left (the patient has an uncompensated forefoot varus bilaterally; he is already partially pronated on the right, so it may appear to be less abrupt)
toeing off in supination more pronounced on the left (due to the internal torsion and forefoot varus)
The Gait Guys. Increasing your foot and gait IQ with each and every post.
What can we learn from a trip to the museum and ancient pachyderms?
Lessons from the Denver Museum of Science and the “Mammoths and Mastodons” exhibit.
Leave it to gait nerds to notice stuff like this. These are the things that keep us up at night.
Look carefully at the last 2 pictures, especially the femurs. Besides their grandious size, what do you see. Femoral anterversion! The angle of the femur head with the shaft of the femur is quite large. We remember from our discussion of anteversion previously (see here); that femoral anteversion allows a greater amount of internal rotation of the head of the femur in the acetabulum (ie the ball in the socket).
Now look at the top picture. Besides a cross over gait that Dr Allen was quick to point out. What do you see? Ok…tremendous glutes : ). What else? Look at the second picture for a hint. You got it! Internal rotation of the legs.
Think about how pachyderms are put together compared to say, reptiles, specifically lizards. The legs are UNDER the body in the former and STICK OUT from the body in the latter. Watch them walk. The latter swing their tails and the former have the legs under their center of mass.
Extrapolate this to human gait (We know, it’s a stretch, but you have a great imagination). Some people have their weight under their body (ie, they have sufficient internal rotation of the hips to allow this; many of these folks have more anteverision than retroversion. also remember that we are speaking versions, NOT torsions here). Think about retroverted folks. Wider stance, wider gait, just like reptiles.
Ok, maybe this was a stretch, but it was cool, no?
The Gait Guys. Comparing pachyderms to humans….reallly.
all material copyright 2013 The Gait Guys/The Homunculus Group. All rights reserved.
Remember torsions and versions? If not, click here, here, here and here for a review.
In the top left view, you are seeing the left foot in a neutral posture with the knee in the (relative) midline. Notice how the foot adducts? This person has INTERNAL TIBIAL TORSION. They also have hammer toes and a cavus (high) arch.
In the top right, the foot is again in a neutral posture and the R foot is adducted EVEN FARTHER. Again, internal tibial torsion along with hammer toes and a cavus foot. For a hint, look at the tibial tuberosity; it should line up with an imaginary line drawn through the 2nd metatarsal.
In the middle left picture I am fully internally rotating the R leg. Hmm, no internal rotation of the hip (note the knee goes little beyond midline). You need 4 degrees of internal rotation of the hip to walk normally and most folks have 40 degrees. This person has FEMORAL RETROTORSION.
In the middle right picture I am fully internally rotating the L leg. Hmm, no internal rotation of the hip here either; in fact, even less than the right. Again, FEMORAL RETROTORSION.
In the bottom two pictures, the goniometer is aligned with the ASIS and tibial tuberosity. I am not sure if you can see it, but it is 18 degrees on the left and 20 on the right. Normally the Q angle is between 8 and 12 degrees. This person has developed compensatory GENU VALGUS.
Does it surprise you he has pain on the outside of his feet? How about knee pain?
So what does this mean?
he will have a decreased progression angle of the feet
he will externally rotate the feet to allow a more normal progression angle and “create” the internal rotation of the hip needed
this will place the knee out side the saggital plane and create a potential conflict at the knee
he will stress the ligaments at the medial knee secondary to his valgus deformity
he will increase the pressure on the lateral condles of the femur and lateral tibial plateau, leading to early degeneration
So what do you do?
normalize, to the best of his (and your) abilities, foot and lower extremity mechanics with manipulation, exercise, etc
Take a look at these pics for a moment, then come back and read.
Ready? Lets see how much you remember about torsions and versions. Take a look at this child that was brought in by their parent (legs were too short to drive themselves : ) ) They were wondering if the child needed orthotics. What do we see?
top left photo: legs are in a neutral position. note the position of the knee (more specifically the tibial tuberosity and patellae can sometimes fake you out. ( OK, maybe not you, but they can sometimes fake SOME people out). The plane of the 2nd metatarsal is LATERAL to the tibial tuberosity, This is EXTERNAL TIBIAL TORSION; it appears greater on the (patients) right (look also at the left lower leg in the center picture as well, it has less torsion). Note also the lower longitudinal arches bilaterally (they are typically higher in non-weightbearing but in children this young they are typically lower in the early stages).
top right photo: I am fully internally rotating the right lower leg and hip. Note the position of the knee; it does not rotate as much as you would expect (normally 40 degrees) when compared to the distance the foot seems to have travelled. This hip is RETRO-TORSIONED (remember we are born anteverted about 40 degrees, which decreases approximately 1.5 degrees per year to puberty, resulting in an 8-12 degree angle in the adult. If you need a review, go back and read the February 27th post). Go back and read our 5 part series on Versions and Torsions (“Are you Twisted ?”).
Center photo: I am fully externally rotating the right leg. Note that range of motion is much greater than internal rotation and exceeds 40 degrees. This supports the previous paragraph, retro-torsion.
Bottom left: I am fully internally rotating the left lower leg. It appears normal with about 40 degrees (or more) of internal rotation. This femur is NORMAL or has NORMAL FEMORAL VERSION.
Bottom right: I am externally rotating the left leg. Motion appears to mimic internal rotation and is approximately equal. This supports the previous paragraph as NORMAL FEMORAL VERSION.
External tibial torsion, R > L
flattened longitudinal arches
Right femoral retrotorsion
Left femoral version, NORMAL
Well, what do you think? Are orthotics going to help this kiddo? No, probably not, they may even make the problem worse, by slowing derotation of the talar head, forcing them into more permanent varus of the forefoot.
How did you do? Can you see now why torsions and versions (the degree of “twistedness” of a limb is so important? They help you understand skeletal development and help you to make clearer decisions.
The Gait Guys. Twisted in a good way. Versioned but not torsioned.
all material copyright 2013 The Gait Guys/The Homunculus Group. all rights reserved. please don’t use our stuff without asking : )
Hopefully you have been keeping us with us. If you missed the 1st 3 of this series, go back 3 weeks and start reading again, or do a search on the blog page for “torsion”.
The final chapter of developmental versions involves the femur. The degree of version is the angle between an imaginary line drawn through the condyles of the femur and an imaginary line drawn through the head and neck of the femur. This is often referred to as the femoral neck angle or FNA.
Beginning about the 3rd month of embryological development (Lanz and Mayet 1953) and reaches about 40 degrees (with an average of 30-60 degrees) at birth. It then decreases 25-30 degrees by adulthood to 8-20 degrees with males being at the lower and females at the upper end of the range.
The FNA angle, therefore, diminishes about 1.5 degrees a year until about 15 years of age. Femoral neck anteversion angle is typically symmetrical from the left side to the right side.
What causes torsion in the first place? By the sixth month in utero, the lumbar spine and hips of the fetus are fully flexed, so perhaps it is positional. Other sources say it coincides with the degree of osteogenesis. There is a growing consensus that muscular forces are responsible, particularly the iliopsoas or possibly the medial and lateral hip rotators.
Additional changes can occur after birth, particularly with sitting postures. “W” sitting or “cross legged” sitting have been associated with altering the available range of motion and thus the FNA, with the range increased in the direction the hip was held in; W sitting causing increased internal rotation and antetorsion and cross legged causing external rotation and retro torsion.
As discussed previously, there are at least 3 reasons we need to understand torsions and versions, They can alter the progression angle of gait, they usually affect the available ranges of motion of the limb and they can alter the coronal plane orientation of the limb.
1. fermoral torsions often alter theprogression angle of gait.In femoral antetorsion torsion, the knees often face inward, resulting in an intoed gait and a decreased progression angle of the foot. This can be differentiated from internal tibial torsion (ITT) by looking at the tibia and studying the position of the tibial tuberosity with respect to the foot, particularly the 2nd metatarsal. In ITT, the foot points inward while the tibial tuberosity points straight ahead. In an individual with no torsion, the tibial tuberosity lines up with the 2nd metatarsal. If the tibial tuerosity and 2nd met are lined up,and the knees still point inward, the individual probably has femoral ante torsion. Remember that a decreased progression angle is often associated with a decreased step width whereas an increased angle is often associated with an increased step width. See the person with external tibial torsion in the above picture?
2. Femoral torsions affect available ranges of motion of the limb. We remember that the thigh leg needs to internally rotate the requisite 4-6 degrees from initial contact to midstance (most folks have 40 degrees) If it is already fully internally rotated (as it may be with femoral retro torsion), that range of motion must be created or compensated for elsewhere. This, much like internal tibial torsion, can result in external rotation of the affected lower limb to create the range of motion needed.
Femoral retro torsion results in less internal rotation of the limb, and increased external rotation.
Femoral ante torsion results in less external rotation of the limb, and increased internal rotation.
3. femoral torsions usually do not effect the coronal plane orientation of the lower limb, since the “spin” is in the transverse or horizontal plane.
The take home message here about femoral torsions is that no matter what the cause:
FNA values that exist one to two standard deviations outside the range are considered “torsions”
Decreased values (ie, less than 8 degrees) are called “retro torsion” and increased values (greater than 20 degrees) are called “ante torsion”
Retro torsion causes a limitation of available internal rotation of the hip and an increase in external rotation
Ante torsion causes an increase in available internal rotationof the hip and decrease in external rotation
Femoral ante torsion will be perpetuated by “W” sitting (sitting on knees with the feet outside the thighs, promoting internal rotation of the femur)
Femoral antetorsion will be perpetuated by sitting cross legged, which forces the thigh into external rotation.
Stay tuned for a case tomorrow to test your learning over the last few weeks.
We remain: Bald, good looking and intelligent…The Gait Guys
All material copyright 2013 The Gait Guys/ The Homunculus Group. All rights reserved. Please ask to use our stuff!