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Post by lawrencebevan on Mar 27, 2008 14:44:07 GMT
Finding the axis in weightbearing.
Pt stands relaxed, you palpate the talar head. The STJ "axis" is more or less in line with a bisection of the head and neck! so wherever that talus is "pointing" so is that "axis". In neutral many feet the talus will point towards the 2nd met and in "ideal" feet in RCSP it will point to the medial side of the 1st met head.
For patients where the axis seems to be pointing to the 1st cuneiform, this is quite medial and this is where a rearfoot post and/or skive can be necessary.
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Post by robertisaacs on Mar 27, 2008 17:18:51 GMT
:)Attaboy lawrence. Back on topic.
Thats a new one on me. Is there anything published on this method?
I've just have a quick butchers at my skeletal feet (the ones i bought from canonbury or found lying around the office, not the ones on the end of my spindly legs) and if i hold a pen in line with the neck of the talus it comes out somewhere medial of the 1st met. Which, considering that these feet are alledgedly "normal" gives some concerns (normal axial location being somewhere around the 2nd met head, again alledgedly).
Also, whilst the heads of the talus are the best way to find STN, im not sure i would trust that i could find them through all that soft tissue accuratly enough to extrapolate an axis.
Unlike the Kirby method (where you can test at points all the way down the axis), a small error at the talus would result in a large error more distily.
Tell you what. I've got a rammed clinic tomorrow. I'll try it the old fashioned way and then your way and see how close they are. Others can do likewise. Be an interesting experiment.
Regards
Robert
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Post by lawrencebevan on Mar 27, 2008 17:51:38 GMT
Its a quick a dirty estamation. It relates to research done by Dr's Kirby and Spooner (he he) that showed the "axis" to more or less bisect the talar neck and head.
Eric fuller has said often you dont need to know the exact axis location but more often an estimate of its medial exit location. If it exits in the middle to proximal arch then you got problems and greater medial support (varus rearfoot post/skive) is needed.
Sources vary on normal, Kirby talks as a "normally functioning" foot havind an axis exit point just medial to 1st met head, correlating to a "slightly" pronated STJ in RCSP.
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Post by podiathing on Mar 27, 2008 21:28:59 GMT
If its quick and dirty....it must be good ya?
I assess axis position in relaxed bipedal stance like lawrence. If its more medial (as he describes) i start thinking about the need to increase 'control'/posting to apply adequate supinatory moments to the STJ to relieve related pathology. This is where the MOSI came from. It is quick, and when added to the supinatory resistance test a nice pair of clinical 'tests'. These clinical tests are of course important, but when you watch these feet walk it is much easier to see where the medial head approximates rather than if the STJ is resupinating!
Interestingly most core-stability mini-squat type assessments and treatment regimes recommend single limb stance with the knee flexing over the 2nd toe. Unless there are any rotational abnormalities, this is also trying to 'address' the issue of a medial axis by initiating the lateral rotators etc. Whether these programs recognise this, or take pronatory moments across the STJ into account is another matter....but if you prescribe a MOSI type appliance its amazing to see the increased ease at which patients can perform these types of closed-kinetic chain tests.
And a nice thing to show to your team physio...
Regards
Paul Harradine
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Post by robertisaacs on Mar 28, 2008 8:07:01 GMT
Could you point me at the reference for that one please ? Ta much.
I would basically agree with that. Most axies start in around the same place so if you can repeatably find where it comes out you can extrapolate the overall position pretty well.
Again, reference please. "biomechanics of the normal / abnormal foot shows a axis exiting slightly lateral to the center of the 1st met head. The SALRE paper puts it slightly more lateral, between one and two. This tends to match my experiance.
Paul
Please don't get me started on lateral rotators! I'm in the middle of a row about that with Sam Randall at the mo and the more i look into coupling systems (see thread on STJ motion on pod arena) and a finite element analysis of the ratio between femoral rotation moments and frontal plane foor moments the more i wish i'd become a plumber!
Perhaps save that one for another day? For the sake of my tenuous grip on sanity?
Regards
Robert
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Post by robertisaacs on Mar 28, 2008 9:47:27 GMT
Ok, got a live one for ya. Patient A. Nice bloke, few years off retirement, works on feet. Massive remodeling around the R ST/TC complex. Sagittal range about 20 degrees (at 9am for ian  ). STJ range all of about 5 degrees and that painful. Very significant tibial varum the likely cause. Impossible to palpate the talar heads for an axial projection that way, Grossly medial axis measured the other way. Photos to follow if i can find the ****ing usb lead. Pain is medial, anterior and lateral around the ankle / ST area. Tried most of what is in the arsenal with little effect. Best outcome so far was an 8 degree medial post with a very thin (6.35mm) valgus pad. Good canditate for a case study? I'm planning to try him with a MOSI set at approx 45 degrees. Thinking lunarsoft as a material (which has a bit of give but not much). Not going to cast him because i don't thing the morphology of the foot / Soft tissue deviations would lend themselves to it so i'm going to be doing a "simple" version of a MOSI. I'll upload some photos when i've made it so you can sneer at my craftsmanship. Any advice / statements to the effect of "OH GOD DON'T" appreciated. I'll keep the community posted. To about 40 degrees . Regards Robert |
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Post by podiathing on Mar 28, 2008 10:04:48 GMT
Robert
Sounds like a definate MOSI candidate. Think about supporting it with a MOSI ext post and angling this up at about 6 degrees too.
I look forward to seeing those pictures
regards
Paul
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Post by robertisaacs on Mar 28, 2008 14:33:26 GMT
Tis done. Insole made, patient coming in Monday for fitting (who says NHS is slow?!). Feedback by this time next week. I'll get the photos on later this evening if i get time. Can't find the flippin usb lead so i'll have to take it home.  The suspense is killing me. Regards Robert |
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Post by blinda on Mar 28, 2008 18:52:44 GMT
Come on....hurry up.
This is exciting!
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Post by robertisaacs on Mar 28, 2008 18:54:11 GMT
As promised  The foot. Note the axis. For real. Ever so medial.  The leg. Thats some kinda crazy amount of tibial varum going on there! The forefoot is perpendicular to the ground.  The medial ankle. Find a talar head in there i'd be very impressed! The insole. A very slightly modified version of the mosi wedge as a simple rather than a cast.  'Bout 30 degrees total. I measured it at 30.74 degrees david ;D  The angle of the axis. Extrapolated from the skin marks with extreme accuracy. The cover is the suede side of grainside pigskin because i wanted something with higher friction (better force vector)  The extrinsic wedge, as per recommendation. So there it is. Reverse engineering a'la me. Regards Robert |
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Post by twirly on Mar 28, 2008 21:07:03 GMT
Hello Robert & the gang, Need to add thanks muchly for the photos. (they even fitted on the whole screen Robert {well done U} I have been totally bloody lost by all the 'mosi' on down kinda talk recently (was awaiting John Wayne to put in an appearance)but piccies = I finally geddit!!! I have an inherent dislike of all things complicated so when I go quiet y'know I'm lost...... Am pleased to announce: TADA  , am once again found (ish). K.I.S.S much lurve, twirls |
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Post by blinda on Mar 28, 2008 22:32:36 GMT
 yay, NOW i know what Paul meant by.. That is an understated medial STA....wish my patients had the forethought to turn up with their axis conveniently tattooed on their foot. |
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Post by robertisaacs on Mar 29, 2008 8:06:57 GMT
Its a dermatological condition called axioderma pigmentosia. The case shown is part of the "bic" subtype. It comes in several forms, notably the "linus" form and the "Pointus" form (shown) although there is good evidence that the latter often develops into the former. Its aetiology is uncertain, however there is some indication that it might be iatrogenic since it is often found in patients who have had orthotics. Therefore it MUST be caused by wearing orthotics (if we take the empirical line of reasoning ). Further research may shed more light on this. Interestingly its demographic distribution is quite irregular with "clusters" of cases occuring around certain point. Some of these seem to correspond with clinic locations, but then some clinics which issue orthotics (quite successfully) do not have an outbreak anywhere near them. Environmental causes can therefore not be ruled out. Fortunatly almost all of my patients present with the condition. This makes assessment much easier. And you are most welcome for the pictures. Regards Robert |
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Post by blinda on Mar 29, 2008 19:42:45 GMT
;D
Grand explanation, I look forward to more published clinical evidence.
Cheers,
Bel
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Post by podiathing on Mar 30, 2008 19:35:02 GMT
Hi Robert I like it...but not the way its placed on a bin Thats a nice way of applying the MOSI to a flat insole. I've just spent the weekend in St Thomas' in London teaching on this. A group of post-grads with a couple of medial STAs, and on the second day sticking felt medial heel wedges onto insole liners. We did gait outcomes with normal felt hemi-wedges and then with the MOSI. Significantly better with the MOSI..and that was just with felt. Let us know how the fitting goes Paul Harradine |
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). STJ range all of about 5 degrees and that painful. 
, am once again found (ish).
Beautiful people are inside out.