Leg Length differences

This can sometime be a hot topic. In orthopaedic circles, what is considered a significant difference between the two legs can be quite large and in chiropractic circles what is considered significant can be quite small. Both sides of the argument can be quite passionate about this.

Reminds me of Payne's Law: "The amount of passion involved in defending a theory and the amount of emotional attachment to a theory is usually inversely proportional to the amount of evidence for that theory"

There is no doubt that having a leg length difference does affect the quality of life and there are many way to measure a leg length difference clinically. There are also just as many arguments about how the body compensates for a leg length difference.

Podiatry Arena has built up a valuable resource of threads that have been tagged for leg length difference, that explores all these issues.

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Functional hallux limitus

I am privileged with the honour of being invited to speak at many conferences. Most recently was at the Podiatric Surgeons conference. When I agreed to speak, I did not think to much about about the topic until I was back from another conference, then I had a OMG why did I agree to talk about that moment ? What the hell am I going to say?

One reason I enjoy speaking at conferences is that it forces me to organise my thoughts and "put them on the line", so I thought I would try and take our traditional understanding of first MPJ dysfunction (ie hallux rigidus; structural and functional hallux limitus) and the windlass dysfunctions (ie no windlass; delayed windlass; high force to establish; disruption during loading) and reconceptualise them in the framework of the mechanical engineering terms of 'stiffness'.

While going through the dot points, I got struck by something: All functional hallux limitus really is, is a temporary increase in the dorsiflexion stiffness of the first MPJ ! It got the thought processes going. (I have written about it here: Reconceptualising Functional Hallux Limitus)

Traditionally we have considered FnHL as being present or absent, when in reality it probably exists on a continuum. If we conceptualise it as a temporary increase in first MPJ stiffness, it then opens the possibility of grading functional hallux limitus (ie a low temporary increase in first MPJ stiffness to a high temporary increase in first MPJ stiffness). Maybe we can measure this !

Should we reconceptualise FnHL as a temporary increase in first MPJ stiffness? What say you?

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Chi Running

Chi running is a "movement" within the running community based a particular running technique based mostly on being more efficient, relaxed and having a midfoot strike. I initially dismissed it as just another one of those fads until I noticed that one of the key Chi running websites had an alliance with New Balance running shoes and they have a shoe that is specific for Chi Running. I wonder where this will go? Will the Pose Running converts get a shoe as well? Chi running is not without controversy, mostly due to the lack of evidence for the claims made by its supporters. I have also written before about Chi Running.

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Research on one foot, two feet, or one person

I have recently reviewed several manuscripts that I recommended that editors not publish due to a fundamental flaw in the methodology. It concerned me enough to post a thread here about it (and will freely admit that I have been guilty of this in the past, but times change as we learn more).

One potentially appealing thing about doing foot or podiatry research is that each subject has two feet, meaning that if you use both feet in the data, you have either doubled your sample size or halved the number of subjects used.

HOWEVER, a key assumption of almost all statistical tests is that the subjects in the sample are independent of each other ..... this means that you can not use two feet from the same person in the sample as they are related (not independent of each other; they are paired) - they have the same body weight; the same blood supply; etc etc ...

The use of the two feet of one subject is no longer acceptable in research due to this lack of independence. This is a common issue in the opthalmologic literature (two eyes or one eye?); the orthopaedic literature (two limbs or one?); the rheumatological literature (eg one knee or two):
"SUTTON et al. Two knees or one person: data analysis strategies for paired joints or organs Ann Rheum Dis.1997; 56: 401-402"

Hylton Menz brought this to our attention in the podiatric literature:
"H . Menz: Two feet, or one person? Problems associated with statistical analysis of paired data in foot and ankle medicine . The Foot , Volume 14 , Issue 1 , Pages 2 - 5, 2004"

Why are researchers still using both feet; still submitting the data for publication using both feet in the analysis; and why are journal editors still permitting them to be published (esp in podiatric journals)?

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Hubscher manoeuvre

There has been some good discussion at Podiatry Arena on the Hubscher maneuver (terminology primarily used in the USA) or Jacks Test (used by the rest of the world!). A poll in that thread showed that 82% of those that responded to the poll used it as a clinical test.

A lot of the discussion focused on it value as a static clinical test used to predict dynamic function and, more important, as a tool that may or may not predict the clinical response to foot orthoses. IMHO, the Hubscher maneuver or Jacks test does have clinical use. When you do this test on different people they respond differently .... that has got to mean something for the way the function! At the end of the day, the disagreements are about what we think it means.

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This is a fun read

At Podiatry Arena, a post was made about some research that should have never been published in the Journal of the American Podiatric Medical Association. It was an appalling piece of research. The inclusion criteria was biased toward getting the result that the researcher wanted. No means or standard deviations of the data was presented, yet the author managed to do a t-test on the data! The results were presented in a categorical fashion in a table. You can not do a t-test on categorical data (chi squared should have been used). I have no idea how or why the research got through the peer review and editorial process.

The fun thing at Podiatry Arena was these criticisms were made of the paper; the author emailed his friends all over the world from several different disciplines who all came along to say way a great guy the author was and how dare we criticise his reputation .... NOT ONE OF THEM addressed the biased inclusion criteria; the lack of presentation of means and standard deviations; the presentation of the data as categorical etc etc .... it don't figure why they blindly accept was this person says without any critical appraisal (mind you a number of contributors to the discussion have a vested financial interest in a product that the author gets royalties from). Anyone smell a rat? (link to discussion)

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The researcher vs the clincian

This dichotomy keeps coming up.

Most recently in this Podiatry Arena thread:
No evidence for foot orthoses in children (notice the questions by clinicians directed at the researchers about the type of foot orthotics used)
Previously it came up in this thread:
Effectiveness of Foot Orthoses to Treat Plantar Fasciitis (notice the really poor understanding by clinicians of just what is a randomised controlled trial)

In a post in this thread: The 5 great FALLACIES of podiatric biomechanics, Kevin Kirby posted: "Researchers will continue to misrepresent the effectiveness of prescription foot orthoses until they understand the concept that skilled orthosis practitioners do not simply hand out cookie-cutter orthoses to patients without needing to occasionally adjust them to improve patient symptoms and improve gait function."

Researchers often complain that clincians "just don't get it".
Clincians often complain that researchers "just don't get it".

I am a researcher and a clincian and I think "I get it". What are we going to do about this? How can researchers conduct clinical trials so that clinicians can "get it". How can clinicians get researchers to see where they are coming from so they can "get it"

What say you? Comments here

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