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STJ transverse plane axis determination

Discussion in 'Biomechanics, Sports and Foot orthoses' started by markjohconley, Jun 21, 2007.

  1. markjohconley

    markjohconley Well-Known Member

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    Dear reader, i; i suspect i am not alone; despite constant practice, am having practical difficulties with the Kirby test to determine transverse plane (tp)anomalies with the STJ axis. I am a disciple to the theory but by crikey it is b****y difficult for me to observe the triplane motion. Is it plausible to assess the tp orientation by passively moving the stj through its rom. The more medially deviated the axis the more sagittal plane component, the more laterally deviated the greater the frontal plane component. The ankle jt motion would need to be eliminated/minimised, by also applying a constant dorsiflexory force on the foot. If i have overlooked a previous thread/post please inform me as i was unable to locate same. Thanks, mark c
  2. Johnpod

    Johnpod Active Member

    Can we know what the Kirby test is please. How is it performed. Also curious to know why you need to isolate the transverse plane movement of the STJ?

    'If I have seen further than most it is because I have managed to see round the big beggars in front'
  3. markjohconley

    markjohconley Well-Known Member

    johnpod, i'm working hard on my written communication skills, obviously still have "scope for improvement". What i meant was when one is attempting to determine if the assessed foot's STJ has a medial or lateral deviation with regard to the transverse plane, usually determined, as far as i know, by applying a anteriorly?dorsally-directed force, with a digit, on the plantar surface of the foot to determine the STJ axis reflection on the transverse plane. How's that!
  4. See:
    Kevin A. Kirby
    Subtalar Joint Axis Location and Rotational Equilibrium Theory of Foot Function J Am Podiatr Med Assoc 2001 91: 465-487.


    A new theory of foot function based on the spatial location of the subtalar joint axis in relation to the weightbearing structures of the plantar foot is proposed. The theory relies on the concept of subtalar joint rotational equilibrium to explain how externally generated forces, such as ground reaction force, and internally generated forces, such as ligamentous and tendon tensile forces and joint compression forces, affect the mechanical behavior of the foot and lower extremity. The biomechanical effect of variations among individuals in the spatial location of the subtalar joint axis are explored, along with their clinical consequences, to offer an additional theory of foot function, which may improve on existing podiatric biomechanics theory. (J Am Podiatr Med Assoc 91(9): 465-487, 2001)

    See also:
    KA Kirby
    Methods for determination of positional variations in the subtalar joint axis J Am Podiatr Med Assoc 1987 77: 228-234.

    KA Kirby
    Rotational equilibrium across the subtalar joint axis
    J Am Podiatr Med Assoc 1989 79: 1-14.

    KA Kirby
    Biomechanics of the normal and abnormal foot
    J Am Podiatr Med Assoc 2000 90: 30-34.

    Simon K. Spooner and Kevin A. Kirby
    The Subtalar Joint Axis Locator: A Preliminary Report
    J Am Podiatr Med Assoc 2006 96: 212-219.
  5. markjohconley

    markjohconley Well-Known Member

    102 views and no responses; being a "half-empty glass" personality-type should i be feeling embarrassed, have i missed some really basic concept? I realise I wouldn't be able to envisage the relected axis on the plantar surface as one would using the application of dorsally directed forces, but wouldn't an indication of deviance be obtained by moving the STJ through its ROM? I get the feeling everyone is laying off till the man sorts me out, don't wait he's helped me enough in the past, someone else have a go, please, thanks, mark c
  6. Never that. There's no such thing as a stupid question. Stupid is not daring to ask and remaining ignorant. I should know, i'm ignorant as anything.

    OK I'll have a go but i probably won't do this justice!

    Whats one of these?

    My answer would be that this looks very much like the hard way to me. I suppose it might be possible to observe an approximation of the Axis by moving the joint passivly but you'd probably need either a lot of experiance or a reference between movement and axial location to get an approximate location.

    Don Green wrote A good article on planal dominance

    Donald R Green, Planal Dominance J Podiatr Med Assoc Feb 1984 No 2 98 - 103

    Where he talks about this kind of thing.

    Whats wrong with the Planter -> dorsal pressure method?Push up. If it supinates try agin a bit more laterally. Repeat until you find the point where it neither supinates nor pronates. Draw an X . Repeat a bit proximal to last time.

    Is there a specific bit of this technique you find hard?

  7. markjohconley

    markjohconley Well-Known Member

    thanks robert

    I meant the transverse plane component of the STJ, that which is 'drawn' on the plantar surface of the foot by connecting the "X" 's
    I couldn't get a location from using the rom observation only whether the STJ axis was medially or laterally deviated. I realise that the orientation of the STJ axis 'moves' with rotational position of the STJ. Please elaborate on the 'reference' reference.
    Will definitely get onto it, thanks
    Yep the,

    thanks again robert
  8. The reference reference was not a reference to a specific reference. I was meaning that for this to work you would have to know how the amount of saggital dominance related to the axial position. I doubt such an algothithm exists. And besides...

    Indeed! You can only get an isolation of the stj axis in the position it's in when you carry out the test! Therefore trying to get an idea of the axial position by moving the foot ain't gonna work because the axial position will be moving during the test! Its a bit schrodinger, observing the joint in this way would cause the reality under observation to change!

    Ah. That bit is important. That presents a problem then!

  9. Mark:

    Even though I'm here at the Disneyland Hotel, lecturing at the Western Podiatric Medical Conference, I hear your impassioned pleas.

    First of all, there is no "Kirby test". I have invented a number of tests, did not name any of them the "Kirby test", so using this terminology (i.e. the "Kirby test") is nonspecific and unclear.

    The technique you are referring to is the "Palpation Method for Determining STJ Axis Location" first described in the article that I wrote 20 years ago (Kirby KA: Methods for determination of positional variations in the subtalar joint axis. JAPMA, 77: 228-234, 1987). This technique has also been described in subsequent publications (Kirby KA, Green DR: Evaluation and Nonoperative Management of Pes Valgus, pp. 295-327, in DeValentine, S.(ed), Foot and Ankle Disorders in Children. Churchill-Livingstone, New York, 1992; Kirby KA: Subtalar joint axis location and rotational equilibrium theory of foot function. JAPMA, 91:465-488, 2001).

    The purpose of the test is not "to observe triplane motion", but rather the purpose of the test is to determine the plantar representation of the subtalar joint (STJ) axis. This test is performed by stabilizing the foot with one hand while the other hand of the examiner is used to apply a force to specific locations of the plantar foot to see how the foot responds to those forces. If the patient's foot responds to the applied force by supinating, then, naturally, the applied force is medial to the STJ axis. If the patient's foot responds to the applied force by pronating, then the applied force is lateral to the STJ axis. However, as the applied force becomes closer to the axis, the examiner should note, if they are practiced enough in the technique, that the STJ does not respond by either pronating or supinating. Once the specific area of the foot where the "point of no rotation" is found, this point is then marked on the plantar foot with a pen. By performing this same procedure from the ankle joint axis level to the forefoot, a line of "points of no rotation" will be found that can then be assumed to be the plantar representation of the STJ axis on the plantar foot.

    And you are not alone, Mark, the technique is quite difficult to master. It actually took me about 3 months of daily practice, when I was first developing the technique, back in 1984-1985 during my Biomechanics Fellowship, to get to the point of where I felt I was consistent in the technique. If I have a student that I can personally teach, it generally takes them a few weeks to learn the technique if they are practicing the technique on a daily basis. I would be happy to help you out but you will need to be as specific as possible with your problems with the technique in order for me to help you without actually being able to physically observe you attempting to perform the technique.

    In response to the other part of your question, the STJ axis spatial location will significantly affect the triplane motion of the foot relative to the leg during range of motion of the STJ. I also described this finding in my 1987 paper and became quite obvious to me 20+ years ago when I was first starting to correlate STJ axis medial and lateral deviation to the quality of STJ motion during open kinetic chain examination of the foot.

    In feet with medially deviated STJ axes, if your hand is loading the 5th metatarsal head to put the STJ through range of motion, from the neutral position to the maximally pronated part of the range of motion of the STJ, your hand will undergo relatively more dorsiflexion and less abduction with pronation motion and will undergo relatively more plantarflexion and less adduction with supination motion. However, in feet with laterally deviated STJ axes, from the neutral position to the maximally pronated part of the range of motion of the STJ, your hand will undergo relatively more abduction motion and relatively less dorsiflexion motion with pronation motion and will undergo relatively more adduction motion and less dorsiflexion motion with supination motion. In other words, the plane of motion that the lateral forefoot makes in 3D relative to the leg is different when the STJ is medially deviated than when the STJ is laterally deviated. This is due to a change in location of the STJ axis relative to the lateral forefoot that will then determine the relative plane of motion of the forefoot to the leg from the neutral position to the maximally pronated position.

    This is actually something that I didn't go into in more detail in this 1987 paper due to me worrying about the paper not being accepted for publication if I had described this more fully and which would have made the paper twice as long. However, it is very important when considering the effects of equinus on the foot and how a foot will either develop excessive STJ pronation moments from equinus or excessive STJ supination moments from equinus. Again, this will probably require another paper someday when I get done with the two chapters I am also supposed to be working on at this time.

    Now, off to California Adventure again with my lovely wife!
    Last edited: Jun 22, 2007
  10. markjohconley

    markjohconley Well-Known Member

    Thanks Robert and Kevin, i've got some more reading to do and redo, all the best, mark c
  11. David Smith

    David Smith Well-Known Member

    Last edited by a moderator: Jun 23, 2007
  12. David Smith

    David Smith Well-Known Member

    Alternatively goto Sputnikmusic.com and buy a copy of 'The Specials' album- 'too much to young' and listen to the track specially dedicated to Robert Isaacs, entitled ' a message to you, Robeer'.

    A Message To You, Robeer
    A special arrangement by Robert Livingstone Thompson
    for Simon Spooner (allegedly)

    Stop your messing around
    Better think of your future
    Time you straightened right out
    Creating problems in town

    Robeer, a message to you
    Robeer, a message to you

    Stop your fooling around
    Time you straightened right out
    Better think of your future
    Else you'll wind up in jail

    Robeer, a message to you
    Robeer, a message to you

    Stop your messing around
    Better think of your future
    Time you straightened right out
    Creating problems in town

    Robeer, a message to you
    Robeer, a message to you
    Robeer, a message to you
    Robeer, a message to you :D :D

    OK Robert! LOL Dave
  13. Craig Payne

    Craig Payne Moderator

    Mark - in Australia, get it from OPC or talk to someone who went to the Hobart conference (it was in their satchels) ... I still have not watched it yet!
  14. Craig:

    From what I have seen of it so far, your DVD is very nicely done. It is interesting how you do some of the measurements differently than I was taught or developed (supine vs prone and prone vs supine) but I think the way the DVD was put together is very informational and should be a big help for most clinicians.

    I just wish we could have had a similar video of other clinicians such as Dr. John Weed or Dr. Mert Root demonstrating the techniques they performed before they passed away. This gives me incentive to possibly start thinking of producing a video series on clinical examination and gait examination skills for distribution along with a video on orthosis therapy. Don't know how I will do it, when I will do it or how I'm going to pay for it, but it really must be done before I forget all that I have learned from the talented clinicians who taught me.

    Good job, Craig and Algeos!

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