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.

Leg length discrepancies and total joint replacments.

5mm cut off ?  MaybeYou are likely to come across hip and knee arthroplasty clients (total joint replacements). When they take a joint out and replace it with a new one, it can be a true challenge to restore leg lengths to equality side to side. Problems often arise down the road once gait is resumed and rehabilitation is completed. It can take time for the leg length discrepancy (LLD) to begin to create compensatory problems. This article seems to suggest that 5mm is the tipping point where gait changes becoming a problem are founded. Other sources will render different numbers, this article found 5mm. The authors found that both over- and underrestoration of leg length/offset showed similar effects on gait and that Gait analysis was able to assess restoration of biomechanics after hip replacement.  I would chose to use the word “change” over restore, since the gait analysis is merely showing the deployed strategies and compensations, never the problem.  But it is a tool, and gait analysis can be a decent tool to show “change”.*Remember, it is not always a product of true length, it can come from the pelvis posturing and/or from the acetabular orrientation, which can be a postoperative sequella. One cannot over look  acetabular inclination, anteversion and femoral component anteversion/retroversion issues.Just remember, before you start making LLD changes with inserts, cork, orthotics etc be sure that you have restored as best as possible, pelvis-hip-spine mechanics because changes here can reflect as a mere leg length discrepancy. And it goes the other way as well, a LLD can cause those changes above.

* Just use your brain and don’t just lift the heel, give them a full sole lift. Heel lifts for this problem are newbie mistakes. Don’t be a newbie.

– Dr. Shawn Allen

Leg length and offset differences above 5 mm after total hip arthroplasty are associated with altered gait kinematicsTobias Renkawitz, Tim Weber, Silvia Dullien, Michael Woerner, Sebastian Dendorfer, Joachim Grifka,Markus Weber

Holy Leg Length discrepancy!

These pix come to us from one of our brethren, Dr Scott Tesoro in Carbondale of a 73 yr old golfer with mild LBP and a  L knee replacement three yrs ago. He has a VERY short R leg (close to an inch).

What you are seeing is he ultimate compensation for a short leg. Note how he takes the shorter side and supinates it (to the max!). You can see the external rotation of the lower leg and thigh to go along with it. If you look carefully and extrapolate how his left leg would look “neutral”, you can see he has internal tibial torsion on this (right) side as well. He has some increased midfoot pronation on the right compared to the left, but not an excessive amount.

A full length sole lift would probably be in order, as well as potentially addressing some of his compensations. Wow, what a great set of pictures !

Using a boot to heal a bone, tendon, post-op ?  Think deeper please.

Please please, please ! If you are going to put your client in a CAM rocker boot/shoe for a fracture, or post-op can you please try to level out the leg length discrepancy caused by the thickness of the boot’s sole ? Please ? Pretty please with sugar on top?

Some boot brands have a huge midsole thickness. This leads to a functionally longer leg length. If they are barefoot much of the day, there will be a huge leg length discrepancy. If in shoes all day, you can offset this with a sole lift in the healthy foot’s shoe or you can add something like this to the outsole. Use common sense. IF someone is in a CAM boot for 6 weeks and thus a longer leg, this is going to promote a knee flexed posture on the boot side (ie. shortens the leg) and/or hyperextension of the healthy leg’s knee, supination of the foot, more forefoot habitus (sustained calf loads) and even frontal plane lurch pelvis gait mechanics (this is why many folks will get opposite hip pain). These embedded gait flaws must be addressed and remedied after they are out of the boot to reset normal gait. We have seen enough problems come to our offices that are suspect as a result of prolonged boot use and failure to reteach normal gait patterns, meaning, to reduce the learned gait behaviors of being in a boot for prolonged periods. Gait retraining is just as important as the rehab post-boot removal.  Of course, this is rarely done.  Using logic is never a bad thing.   

Dr. Shawn Allen, one of the gait guys

Here is a neat device we found to help.http://www.braceshop.com/procare-evenup-shoe-balancer-walker-system.htm?gdftrk=gdfV28018_a_7c2568_a_7c10961_a_7c32290&gclid=Cj0KEQiA37CnBRChp7e-pM2Mzp0BEiQAlSxQCCeL74AvCkYXbQX_jV1jEP27mfocB87f8pSfbo2PZMIaAsOV8P8HAQ

Falling hard; Using supination to stop the drop.

“One thing, affects all things. One change necessitates global change. The more you know, the more you will see (and understand).  The more you know, see and understand, the more responsible you will and should feel to get it right and the more global your approach should become. If your head does not spin at times with all the issues that need to be juggled, you are likely not seeing all the issues you should be seeing.” -Dr. Allen (from an upcoming CME course)

This is a case that has been looked at before but today with new video. This is a client with a known anatomic short leg on the right (sock-less foot) from a diseased right hip joint.  

In this video, it is clear to see the subconscious brain attempting to lengthen the right leg by right foot strike laterally (in supination) in an attempt to keep the arch and talus as high as possible.  Supination should raise the arch and thus the resting height of the talus, which will functionally lengthen the leg.  This is great for the early stance phase of gait and help to normalize pelvis symmetry, however, it will certainly result in (as seen in this video) a sudden late stance phase pronation event as they move over to the medial foot for toe off. Pronation will occur abruptly and excessively, which can have its own set of biomechanical compensations all the way up the chain, from metatarsal stress responses and plantar fasciitis to hip rotational pathologies.  It will also result in a sudden plummet downwards back into the anatomic short leg as the functional lengthening strategy is aborted out of necessity to move forward.  

This is a case where use of a full length sole lift is imperative at all times. The closer you get to normalizing the functional length, the less you need to worry about controlling pronation with a controlling orthotic (controlling rate and extent of arch drop in many cases). Do not use a heel lift only in these cases, you can see this client is already rushing quickly into forefoot loading from the issues at hand, the last thing you should be doing is plantarflexing the foot-ankle and helping them get to the forefoot even faster !  This will cause toe hammering and gripping and set the client up for further risk to fat pat displacement, abnormal metatarsal loading, challenges to the lumbricals as well as imbalances in the harmony of the long and short flexors and extensors (ie. hammer toes). 

How much do you lift ?  Be patient, go little by little. Give time for adaptation. Gauge the amount on improved function, not trying to match the right and the left precisely, after all the two hips are not the same to begin with. So go with cleaner function over choosing matching equal leg lengths.  Give time for compensatory adaptation, it is going to take time.  

Finally, do not forget that these types of clients will always need therapy and retraining of normal ankle rocker and hip extension mechanics as well as lumbopelvic stability (because they will be most likely be dumping into anterior pelvic tilt and knee flexion during the sudden forefoot loading in the late midstance phase of gait). So ramp up those lower abdominals (especially on the right) !  

Oh, and do not forget that left arm swing will be all distorted since it pairs with this right limp challenge. Leave those therapeutic issues to the end, they will not change until they see more equal functional leg lengths. This is why we say never (ok, almost never) retrain arm swing until you know you have two closely symmetrical lower limbs. Otherwise you will be teaching them to compensate on an already faulty motor compensation. Remember, to get proper anti-phasic gait, or better put, to slow the tendency towards spinal protective phasic gait, you need the pelvic and shoulder “girdles” to cooperate. When you get it right, opposite arm and leg will swing together in same pendulum direction, and this will be matched and set up by an antiphasic gait.

One last thing, rushing to the right forefoot will force an early departure off that right limb during gait, which will have to be caught by the left quad to dampen the premature load on the left. They will also likely have a left frontal plane pelvis drift which will also have to be addressed at some point or concurrently. This could set up a cross over gait in some folks, so watch for that as well.

“One thing, affects all things. One change necessitates global change. The more you know, the more you will see (and understand).  The more you know, see and understand, the more responsible you will and should feel to get it right and the more global your approach should become. If your head does not spin at times with all the issues that need to be juggled, you are likely not seeing all the issues you should be seeing.” -Dr. Allen (from an upcoming CME course)

Shawn Allen, one of the gait guys.

Difference between adult and infant gait compensation.

We highly doubt the infants compensated to the point of “recovering symmetrical gait”. It just isn’t possible seeing as there was frank asymmetry in leg length. However, it is quite possible they accomodated quicker with a more reasonable compensation, that MAY have appeared to have less limp. We did not do the study, but over a beer we might guess that the investigators might agree that our verbiage is closer to accurate. None the less, cool stuff to cogitate. We are very appreciative of this study, there is something to take from this study.

“The stability of a system affects how it will handle a perturbation: The system may compensate for the perturbation or not. This study examined how 14-month-old infants-notoriously unstable walkers-and adults cope with a perturbation to walking. We attached a platform to one of participants’ shoes, forcing them to walk with one elongated leg. At first, the platform shoe caused both age groups to slow down and limp, and caused infants to misstep and fall. But after a few trials, infants altered their gait to compensate for the platform shoe whereas adults did not; infants recovered symmetrical gait whereas adults continued to limp. Apparently, adult walking was stable enough to cope with the perturbation, but infants risked falling if they did not compensate. Compensation depends on the interplay of multiple factors: The availability of a compensatory response, the cost of compensation, and the stability of the system being perturbed.”- From the Cole et all study (reference below)

– thoughts by Shawn Allen


Infant Behav Dev. 2014 Aug;37(3):305-14. doi: 10.1016/j.infbeh.2014.04.006. Epub 2014 May 20.Coping with asymmetry: how infants and adults walk with one elongated leg.Cole WG1, Gill SV2, Vereijken B3, Adolph KE4.


Eating up a cardinal plane.

Simple post, simple principle today.  We found this case on the web, somewhere. Wish we could remember so we could give credit. 

Looks like simple right leg length discrepancy but the point we wanted to make is that any time you deviate into a plane, you eat up length. In this case, the right knee is severely valgus and that has at least in part contributed to a shorter limb and unleveling of the pelvis. And, it is not uncommon that rotation axis are changed when frontal or sagittal planes are compromised. It is easy to see this on the x-rays, if the foot posturing isn’t at least noted, look at the spacing between the tibia and fibula .  .  .  . rotational planes have changed as well. Is it from the femur or tibia? That is the topic of another day. 

In the larger photo you will notice that even with the right foot lifted there is still a pelvis unleveling. How can that be, unless it was further unleveled that what we are seeing ?  Well, just because you lift to fix doesn’t mean the lift will not enable further collapsing into the weakness and deformity.  We have described this principle on the topic of EVA shoe foam deformation.  When the foot presses the foam into the deformation, it leaves more room for possibly further and faster deformation loads (perhaps more so than had a new shoe been prescribed). So in some cases, more lift can allow more deformation.  How far, well as in this photo, at least until the right knee slams into the left knee and stops further deformation.

So, seeing a plane deficit clues you into possible unleveling of the pelvis and abnormal joint loading responses. It should clue you into looking for another cardinal plane compromise as well. But make no mistake, just adding a lift doesn’t mean the deformation is remedied and not enabling further deformation. It is possible that you can make your client worse if you do not teach them how to find the appropriate motor patterns with the lift so they can learn to protect the parts. Often teaching these types of clients how to control their deformities (when and if possible) is where the gold lies, not in just leveling out the foundation. 

One more “beating of the dead  horse”, lift the whole foot, heel and forefoot with a sole lift when you are “lifting and leveling”. Lifting only the heel puts them into ankle plantar flexion and can often facilitated earlier and faster forefoot loading and even earlier knee flexion.  Save the heel lift as a possible consideration when there are posterior compartment contractures or inflammation.  Certainly we could have gone into functional and structural leg length discrepancies, but we have blogged excessively on that topic in the past. Go ahead and search our blog if you want more on those topics.

Take home point, “just because you lift, doesn’t mean you are truly lifting, you may enable the opposite”.

Shawn Allen, one of the gait guys