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  1. David Smith

    David Smith Well-Known Member


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    Sometimes I find an apparent leg length difference that is difficult to define.
    The leg with the lowest iliac crest (let's ay the right side) also has the greatest pronation at the STJ and if you measure leg length with a tape measure, from say GT to lateral malleolus, then they appear to be equal. However the length from GT to popliteal fossa is longer on the high iliac crest side (left side) i.e. femur appears to be longer. This can be seen when laying supine with knees flexed and feet flat on the ground, the longer femur side (left side) shows as a higher knee level. Putting the right (most pronated) STJ in neutral or vertical calc does not change the hip level difference by much i.e. the low right hip is not due to right stj pronation.
    I can't quite work this out? can it be that the pelvis is misaligned i.e. the relative position between the innominates in the frontal plane.
    Anyone able to throw some light here?

    Dave Smith
     
    Last edited: Nov 27, 2012
  2. Brian A. Rothbart

    Brian A. Rothbart Well-Known Member

    The reason LLD appear to be so difficult to understand is that there are mutiple possible etiologies. First, one needs to determine if they are dealing with a true anatomical LLD (e.g., trauma, genetic etc) or a functional LLD.

    Assuming you are dealing with a FLLD, it can be the result of a descending or ascending postural distortional pattern. On my research site I use anatomical animations which I believe makes it easier to understand, but below I will give a brief description:

    If you are dealing with a FLLD resulting from foot pronation, both innominates displace forward (this very slight motion is occuring at the SI Joint). The more forwardly rotated innominate is under the foot that is more pronated. When you evaluate this patient standing, the PSIS is higher (that innominate is more forwardly rotated) under the foot that is more pronated. This is the typical LLD pattern one sees in a pure ascending postural pattern (e.g., nothing coming from the cranium). When you place this patient prone, all bets are off as to what you will see. This is because pronation (in a gravitational field) is no longer determining the position of the innominates. Instead, prone, the state of muscular contraction enveloping the SI joint will determine the leg length pattern. And if you put that same patient supine, it can become even more confusing because on a fairly hard table, the PSIS will shift depending on the pressure points (from the hard table) on the PSIS. That is depending on how the patient is placed supine can dramatically impact the apparent LLD.

    Bottom line, with Pure Ascending Postural Distortional Patterns, evaluate the patient standing barefooted, not on the table.

    There is another whole category of LLD that result from Descending Postural Distortional Patterns (e.g., resulting from malocclusions, sacral occipital subluxations, atlas divergencies) that are not typically taught in Podiatric Universities. I discuss these in detail on my website at http://rothbartsfoot.es/AbnormCranMech.html I encourage you to take a look. But basically, in general (not always), the Descending Patterns are mirror images of the Ascending Patterns (sound confusing, but makes sense once you see how it works). The reason being is that the resulting LLD from a descending pattern is due to a tilt (roll) of the pelvis, whereas the resulting LLD from an ascending pattern is due to forward (anterior) rotations of the innominates.

    What does become very complicated is when you have both distortional patterns (from the feet and cranium) occurring at the same time. The reason being is that the normal (read that as 'typically predictable') LLD patterns are skewed due to the interaction of the two postural distortional patterns acting on the patient at the same time. At this time, the only way I know of to treat these patients is via computerized global postural analyses in conjunction with cranial radiographs. I just recently had my paper on this subject provisionally accepted for publication. Once published I will provide the details.

    Hope this helps.

    Brian
     
  3. Peter1234

    Peter1234 Active Member

    I have no idea, i normally measure leg lenth inequality from the lateral maleolus to the belly button
     
  4. David Wedemeyer

    David Wedemeyer Well-Known Member

    David I think this thread may interest you if you have not previously read it or reviewing it if you have may be useful, especially my discussion with Kevin:

    http://www.podiatry-arena.com/podiatry-forum/showthread.php?t=3217&page=2
     
  5. Brian A. Rothbart

    Brian A. Rothbart Well-Known Member

    Hi Peter,

    The measuring protocol you are describing above is typically used to rule out an Anatomical Leg Length Discrepancy, and if it does exit, you can quantify it (cm units).

    Brian
     
  6. drdebrule

    drdebrule Active Member

    I palpate the ASIS and order standing AP pelvis X-rays ( measure a drop down from the acetabular head) to estimate limb length difference. Also, asking patient to keep legs straight and touch toes is helpful (can see which way spine/upper deviates from midline).

    When you get down to it a trial and error approach using observational gait analysis might give the best answer. Put a 1/8 or 1/4 inch heel lift in patient's shoe. Look for improved gait symmetry and improved function. Arm swing symmetry should improve. Video and in-shoe pressure analysis may also be helpful if you have access to these technologies.
     
  7. Brian A. Rothbart

    Brian A. Rothbart Well-Known Member

    I do not use heel lifts because they can rotate the innominates anteriorly. Instead, if there is a true ALLD, I use full heel to toe platforms to accommodate for the LLD.

    Brian
     
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