The amazing power of compensation. Coming to a patient in your office… Maybe today

This gal has had a right sided knee replacement. She has an anatomical right short leg, a forefoot supinatus, an increased Q angle and a forefoot adductus. So, what’s the backstory?

When we have an anatomical short leg, we will often have a tendency to try to “lengthen“ that extremity and “shorten” the longer extremity. This is often accomplished through pelvic rotation although sometimes can be with knee flexion/extension or change in the Q angle. When the condition is long-standing, the body will often compensate in other ways, such as what we are seeing here.


The fore foot can supinate in an attempt to lenthen the extremity. Note how the right extremity forefoot is in varus with respect to the rearfoot, effectively lengthening the extremity. As you can see from the picture, this is becoming a “hard“ deformity resulting in a forefoot varus.


Over time, the forefoot has actually “adducted “ as you can see, again in an attempt to lengthen the extremity. Remember that supination is plantar flexion, abduction and inversion, all three which are visible here.

You will also see that the Q angle is less on the right side (se above), effectively lengthening that extremity, but not quite enough as we can see from the picture :-)

Dr Ivo Waerlop, one of The Gait Guys

#forefootadductus #shortleg #kneereplacement #tkr #forefootvarus #gait #thegaitguys

Support for visual gait analysis... with respect to leg length discrepancies

image credit:

image credit:

We talk about leg length discrepancies all the time here on the blog and sometimes, how small discrepancies cause changes in peoples biomechanics. The gold standard for measuring a leg length difference is full length lower extremity X ray, but this presents a problem due to the ionizing radiation, accessibility as well as impracticality of X rays every person with a suspected difference.

We have talked about different compensations as to how to get around a leg length discrepancies. Last week we actually did a tell a seminar on this entire subject. Your patient or client needs to “create clearance” for the longer leg side. This can be accomplished in many ways.

The 5 most common strategies (keep in mind there are many more) are:

  • lean the torso to the short leg side (essentially hip adduction of the longer side)

  • hike the torso on the long leg side

  • circumduct the longer lower extremity

  • increase plantar flexion of the calf of the short leg side

  • increase hip and knee flexion on the longer leg side

And that is exactly what this study found. They looked at kinematics in people with anatomical leg length discrepancies and found that hip adduction as well as increased hip and knee flexion were 2 variables that were consistent in folks with anatomical differences and suggest these variables are a useful screening tool.

Paying attention to how people move and looking for asymmetries. In our opinion, that’s the name of the game : )

Dr Ivo Waerlop, on of The Gait Guys

Zeitoune GNadal JBatista LAMetsavaht LMoraes APLeporace G.Prediction of mild anatomical leg length discrepancy based on gait kinematics and linear regression model. Gait Posture. 2019 Jan;67:117-121. doi: 10.1016/j.gaitpost.2018.09.027. Epub 2018 Sep 29.

#LLD #leglengthdifference #leglengthinequality #visualgaitanalysis #thegaitguys #gaitanalysis

Wild Haggis? Leg length discrepancies on the uphill side? What?

An old Scottish myth has it that the wild haggis (given the fitting taxonomic moniker Haggis scoticus ) is a small fictitious creature (although many folks visiting Scotland believe they are real) that has legs that are longer on one side than the other. There are two varieties: in one the right fore and hind limb are shorter and the other, of course, the left. The asymmetry helps the haggis to circumnavigate the steep mountainsides of its native terrain, but only in a clockwise (if the right legs are short) or counter clockwise (if the left legs are short) direction, so as to not roll down the steep hillside and come to an untimely death; this is purported to be one of the reasons for their near extinction (the other was the introduction of sheep).

The two species coexist peacefully but are unable to interbreed in the wild because in order for the male of one variety to mate with a female of the other, he must turn to face in the same direction as his intended mate, causing him to lose his balance before he can mount her. As a result of this difficulty, differences in leg length among the haggis population are further accentuated, as is there dwindling numbers.

image source:

image source:

It’s an amusing concept, but unfortunately there’s a non-mythical human corollary: Leg-length discrepancies (LLDs), which do not discriminate and affect a wide variety of people, including children with cerebral palsy, people who’ve had hip and knee replacements, and those with scoliosis, pelvic obliquity, or certain muscle contractures/dysfunctions.

Haggis is actually a Scottish dish; lungs and liver of a sheep cooked with other ingredients inside its stomach. Yum (Not!) We are not sure why or how the two are related but it does make for an interesting post : )

Learn more about LLD’s and their compensations by joining us Wednesday, April 17th 5 PST, 6MST, 7CST and 8 EST on Biomechanics 307

Dr Ivo Waerlop, one of The Gait Guys

#haggis #wildhaggis #LLD #leglengthdiscrepancy #leglengthdifference #leglengthinequality #gait #thegaitguys

There is more than one way around an LLD....

Leg length discrepancies. Love them, hate them, they happen. They can be either functional, anatomical or both.

No matter what the cause, there are numerous ways to compensate for a leg length discrepancy. Today we are going to look at one of the more common ones, "leaning" to the short leg side to create enough clearance for the opposite lower extremity. This patient has a left sided short leg. Note how he abducts his pelvis, utilizing both the stance limb gluteus medius and swing limb quadratus lumborum of the left leg to create enough space to swing the right leg through.

Want to know more about LLD’s and their compensations? Join us on, Wednesday, April 17th for Biomechanics 307. 6 PM Mountain time. See you there!

Dr Ivo Waerlop, one of The Gait Guys.

#LLD #leglengthdifference #leglengthdiscrepancy #leglengthinequality #compensation #gait #gait analysis #thegaitguys

Subtle clues to an LLD?

Leg length discrepancies, whether their functional anatomical, have biomechanical consequences north of the foot. This low back pain patient exhibited 2 signs. Can you tell what they are?

can you see the difference ?

can you see the difference ?

how about now?

how about now?

compare right to left

compare right to left

compare right to left

compare right to left

can you see the difference in the Q angles?

can you see the difference in the Q angles?

Look at the first picture and noticed how the left knee is hyper extended compared to the right. Sometimes we see flexion of this extremity. This is to "functionally shorten" that extremity.

Now look at the Q angles. Can you see how the left QL angle is greater than the right? This usually results from a long-term leg length discrepancy where the body is attempting to compensate by increasing the valgus angle of that knee, effectively shortening the extremity.

Dr Ivo Waerlop, one of The Gait Guys

#subtle #clues #LLD #leglengthdiscrepancy #leglengthinequality #thegaitguys #gaitabnormality

Got hip extension?

Because she sure could use some...

we have see this gal before… yesterday in fact

  • left plantar plate lesion (yes, conformed on ultrasound)

  • left sided anatomical leg length discrepany

  • bilateral internal tibial torsion

  • incompetent L quadratus lumborum

  • adequate hip extension and ankle dorsiflexion available to her

  • lack of endurance in her abs

yep, lots more, but that is enough for now

note that she has plenty of ankle dorsiflexion, more on the right. this is due to her right leg being anatomically longer and has to travel through a greater range of motion

look at the knee and the hip articulations to assess hip extension. It should match ankle dorsiflexion, no?

Dr Ivo Waerlop, one of The Gait Guys

#gait #gaitguys #thegaitguys #hipextension #LLD #quadratuslumborum #internaltibialtorsion #anklerocker #ankledorsiflexion

3 things

Its subtle, but hopefully you see these 3 things in this video.

I just LOVE the slow motion feature on my iPhone. It save me from having to drag the video into Quicktime, slow it down and rerecord it.

This gal has a healing left plantar plate lesion under the 2nd and 3rd mets. She has an anatomical leg length deficiency, short on the left, and bilateral internal tibial torsion, with no significant femoral version. Yes, there are plenty of other salient details, but this sketch will help.

  1. 1st if all, do you see how the pelvis on her left dips WAY more when she lands on the right? There is a small amount of coronal plane shift to the right as well. This often happens in gluteus medius insufficiency on the stance phase leg (right in this case), or quadratus lumborum (QL) deficiency on the swing phase leg (left in this case) or both. Yes, there are other things that can cause this and the list is numerous, but lets stick to these 2 for now. In this case it was her left QL driving the bus.

  2. Watch the left and right forefeet. can you see how she strikes more inverted on the left? this is a common finding, as the body often (but not always) tries to supinate the shorter extremity (dorsiflexion, eversion and adduction, remember?) in an attempt to “lengthen” it. Yes, there is usually anterior pelvic tilt accompanying it on the side, because I knew you were going to ask : )

  3. Look how her knees are OUTSIDE the saggital plane and remain there in her running stride. This is commonly seen in folks with internal tibial torsion and is one of the reasons that in our opinion, these folks should not be put medially posted, torsionally rigid, motion control shoes as this usually drive the knees FURTHER outside the saggital plane and can macerate the meniscus.

Yep, lots more we could talk about on this video, but in my opinion, 3 is a good number.

Dr Ivo Waerlop, one of The Gait Guys

#thegaitguys #gaitanalysis #footpain #gaitproblem #internaltibialtorsion #quadratuslumborum #footstrike

What does a pedograph of a person with hallux limitus look like?


Take a good look at the pedographs above. Can you figure out which side has the hallux limitus from the pictures? 

You would think that with hallux limitus there would be increased printing over the distal phalanx of great toe and possibly over the distal metatarsal as seen in the print of the right foot. This would make sense as if you have limited motion here and the pressure will be more forward. However, often times Hallux limitus is painful and the patient develops a compensation to NOT load the joint, as we see on the print of the left foot. We see the lack of printing under the first metatarsal head and increased printing laterally in the foot from avoidance of that joint. Also notice a slight increased printing in the right heel teardrop (hash marks are more filled in) and slight widening of it anteriorly. He has a right sided leg length discrepancy and we would normally expect an increased amount of pronation on the longer leg side, however because of the weight shift to the left we are seeing increased pronation on the right. Now, with this valgus moment of the right foot do you understand why the printing is so heavy under the first metatarsal and distal phalanx. Note also the increased printing at the distal phalanx of toes number two, three and five on the right hand side in an attempt to stabilize as his center of gravity shifts to the right.

And now you know!

Dr Ivo, one of The Gait Guys

#halluxlimitis, #gaitanalysis, #pedograph, #leglengthdiscrepancy, #LLD

More subtle clues..LLD's


This gentleman presented to the office with left-sided knee pain at the medial collateral ligament following a cutting injury, moving from right to left with the left foot planted. As you can see, he has an anatomical leg length discrepancy with tibial and probable femoral length deficiencies on the left side. Can you see the subtle, increased tone of the long flexors of the toes on the left hand side as it evidenced by the increased prominence of the long extensor tendons to a greater degree on the shorter side? This is a common compensation seen in true leg length discrepancies with clawing of the toes in attempt to create stability on the shorter leg side. Often times, the progression angle on the shorter side will be increased as well.

And why does this guy have hip pain?

line up the center of the heel counters with the outsoles, and what do you see?

line up the center of the heel counters with the outsoles, and what do you see?

can you see how the heel counter is centered on the outsole, like it is supposed to be

can you see how the heel counter is centered on the outsole, like it is supposed to be

notice how the heel counter of the shoe is canted medially on the outsole of the shoe, creating a varus cant

notice how the heel counter of the shoe is canted medially on the outsole of the shoe, creating a varus cant

Take a guy with lower back and left sided sub patellar pain that also has a left anatomically short leg (tibial) and bilateral internal tibial torsion and put him in these baby’s to play pickleball and you have a prescription for disaster.

Folks with an LLD generally (soft rule here) have a tendency to supinate more on the short leg side (in an attempt to make the limb longer) and pronate more on the longer leg side (to make the limb shorter). Supination causes external rotation of the lower limb (remember, we are trying to make the foot into a rigid lever in a “normal” gait cycle). this external rotation with rotate the knee externally (laterally). Folks with internal tibial torsion usually rotate their limb externally to give them a better progression angle (of the foot) so they don’t trip and fall from having their feet pointing inward. This ALSO moves the knee into external rotation (laterally), often moving it OUTSIDE the saggital plane. In this case, the knee, because of the difference in leg length AND internal tibial torsion AND the varus cant of the shoe, has his knee WAY OUTSIDE the saggital plane, causing faulty patellar tracking and LBP.

Moral of the story? When people present with a problem ALWAYS TAKE TIME TO LOOK AT THEIR SHOES!

Got Short leg?

Ahhhh. They get it!


Our favorite quote from this article " Understanding limb-length compensation
We encourage you to pay as much attention to any abnormal compensation pattern as you do to the LLD itself. It is well documented that abnormal biomechanics, such as you would find in a compensatory pattern, can result in vibratory forces and microtrauma along the closed kinetic chain (Figure 1). The spinal facet; hip, knee, ankle and foot joints; and their associated muscles may suffer repetitive microtrauma resulting in sprain, strain, or degenerative joint disease. By addressing compensatory neuro-musculoskeletal function, you may be able to assist the patient with a cascade of dysfunction through the musculoskeletal system.

We also encourage you to make use of gait assessment technology to quantify, document, and monitor patients’ progress. Application of reproducible, documented metrics is essential to communicate effectively within a multidisciplinary system that is committed to practicing evidence-based medicine."


A visual example of the consequences of a leg length discrepancy.

This patient has an anatomical (femoral) discrepancy between three and 5 mm. She has occasional lower back discomfort and also describes being very “aware” of her second and third metatarsals on the left foot during running.

You can clearly see the difference in where patterns on her flip-flops. Note how much more in varus wear on the left side compared to the right. This is most likely in compensation for an increased supination moment on that side. She is constantly trying to lengthen her left side by anteriorly rotated pelvis on that side and supinating her foot  and trying to “short” the right side by rotating the pelvis posteriorly and pronating the foot.

With the pelvic rotation present described above (which is what we found in the exam) you can see how she has intermittent low back pain. Combine this with the fact that she runs a daycare and is extremely right-handed and you can see part of the problem.

Leg length discrepancies become clinically important when they resulting in a compensation pattern that no longer works for the patient. Be on the lookout for differences and wear patterns from side to side.


So a patient presents to your office with a recent history of a L total knee replacement 8 weeks ago AND a recent history of a resurgence of low back pain, supra iliac area on the L side. Hmmmm. Hope the flags went up for you too!

His global lumbar ROM’s were 70/90 flexion with low back discomfort at the lumbo sacral junction, 20/30 extension with lumbosacral discomfort, left lateral bending 10 degrees with increased pain (reproduction); right lateral bending 20 degrees with a pulling sensation on the right. Extension and axial compression of the lumbar spine in left lateral bending reproduced his pain.

Neurologically he had an absent patellar reflex on the left, with diminished sensation over the knee medially and laterally. Muscle strength 5/5 in LE; sl impaired balance in Left single leg standing. There was incomplete extension of the left knee, being at 5 degrees flexion (right side was zero).

He has a right sided leg length deficiency (or a left sided excess!) of 5 mm. Take a look at the tibial lengths in the 1st 3 pictures. See how the left is longer? In the next shot, do you see how the knee cannot completely extend? Can you imagine that the discrepancy would probably be larger if it did?

Now look at the x rays. We drew a line across from the non surgical leg to make things clearer.

Now, think about the mechanics of a longer leg. That leg will usually pronate more in an attempt to shorten the leg, and the opposite side will supinate to attempt to lengthen. Can you see how this would cause clockwise pelvic rotation (in addition to anterior pelvic rotation)? Can you see this patients in the view of the knees from the top? Do you understand that the lumbar spine has very limited rotation (about 5-10 degrees, with more movement superiorly (1)  ). Does it make sense that the increased range of motion could effect the disc and facet joints and increase the patients low back pain?

So, how do we fix it? Have you seen the movie “Gattica”? Hmmm….A bit extreme. How about a full length 3mm sole lift to start, along with specific joint manipulation to restore normal motion and some acupuncture to reduce inflammation? We say that is a good start.

The Gait Guys. Increasing your gait literacy with each and every post. If you liked this post, please send it to someone else for them to enjoy and learn. 

(1) Three-Dimensional In Vivo Measurement of Lumbar Spine Segmental Motion Ruth S. Ochia, PhD, Nozomu Inoue, MD, PhD, Susan M. Renner, MS, Eric P. Lorenz, MS, Tae-Hong Lim, PhD, Gunnar B. Andersson, J. MD, PhD, Howard S. An, MD Spine. 2006;31(15):2073-2078.