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Hi all.
There is some evidence to support the concept of circadian variation in joint ROM.

Essentially what this means is that joint ROM alters over a 24-hour period. This is not as simple as "stiff after exercise" or "loose in the morning, stiff at night" but seems to follow no particular pattern.
The best ref I could find for this is :
Yung P, Unsworth A, Haslock I. Measurement of stiffness in the metacarpophalangeal joint: Circadian variation. Clin Phys. Physiol Meas,. Vol 5, no 2 57-65 (1984).

I also had to do a little work on this myself and found that ankle joint complex (AJC) frontal plane ROM varied by up to 6 degrees in one subject over the course of one day. This was measured using a purpose-built rig, rather than a hand-held instrument (unpublished, but can be viewed in my MSc thesis at University of Durham, UK, if anyone is interested :eek: ).

In view of the practice of measuring Joint ROM during a biomech examination, could this variation affect overall theraputic results, and should we be looking at specific protocols when doing a biomech examination (eg measuring after loosening the AJC and subtalar joints by manipulation, or carrying out biomech examination at a specific time of day) :confused:
What do others think?
Regards,
David

 

Hi David

My initial response is to say it is not an area I have considered.

Whether a casted orthosis could be so accurately made to account for this degree of variation during the day I suspect not ( and think of what would be charged for it. Still there's a thought!!). Whether you go for an average of the variation and post, adapt arch height or pitch the device accordingly is an interesting question.

In the case of lig laxity there may not be a need to take this variation into account :confused: In instances where limited AJC rom is considered muscular or ligamentous in origin it may be worthwhile considering if a device could be made to control GRF and torque forces that may initiate stiffening through poor proprioceptive feed back during the day:

i.e. How much of the low ROM in the morning is resulting from soft tissue stress as the day proceeds?

This is not the same as suggesting stiffness after exercise but a thought that the body may be self protecting.

All of this assumes that the circadian variation is being considered abnormal!! It may well be natures protective and adaptive measure.

Apologies if my guesses are butchering biomechanical concepts but I come at it from a very amateurish position and knowlege.

Of course it is a question that follows on nicely from Cameron's view of the importance of Saggital plane action.

cheers

Ian

 

Hi Ian,

"All of this assumes that the circadian variation is being considered abnormal!! It may well be natures protective and adaptive measure."
I believe it to be normal. The reference I gave provides further information, and you can get a really good flavour of what circadian variation is from reading it.

"Apologies if my guesses are butchering biomechanical concepts but I come at it from a very amateurish position and knowlege."
I think most of us who are involved in podiatric biomech will readily admit that we don't have all the answers :confused: .
Circadian variation is simply another variable to add to the melting pot.
In fact it may be more important to take this into account when carrying out research which involves examining joint ROM, rather than to apply it specifically to pod biomech.
Regards,
David

 

Hi Admin,
Thanks for that.
Seems like we shouldn't be ignoring diurnal/circadian variation after all?

Actually, I did some work with only 7 subjects, but measured coronal ROM at the ankle joint complex (with a purpose-built rig with good reliability/repeatability) every two hours over a 12-hour period.

Time to write up and submit for publication methinks?

Regards,
david