ronm
Full Member
but a simple man working against insurmountable odds
Posts: 141
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Post by ronm on Feb 26, 2008 15:13:15 GMT
have heard of the jacks test but never used it - what do you do?
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Post by robertisaacs on Feb 27, 2008 8:35:19 GMT
Well if nobody else is going to, i'll have a shot...
My understanding is:-
Basically its a test for the tension of the windlass. Stand the patient up and dorsiflex their hallux with one hand, with your other hand under their arch. At a certain point the planter fascia will acheive sufficient tension to engage the windlass and the arch will raise visibly (and you will feel it).
The diagnostic value is threefold. Firstly the point at which the windlass becomes active. If it kicks in too soon it might indicate that there is excessive tension in the PF and your prescription might need something to slacken some of that tension off. If you get 45 degrees dorsi and the arch has not moved its a pretty fair indication that the windlass is not working as it should and that might explain a poor recovery form proation at the heel lift stage of gait. You prescription then might need something to encourage the windlass to work more effectivly. Finally if the planter fascia is sticking out of the sole of the foot like a violin string it might be worth considering a plantar fascial groove in your orthotic to avoid aggravation / tension from the insole.
Hope this helps. If anyone else knows any different please say! its a while since i learned that one.
Regards Robert
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ronm
Full Member
but a simple man working against insurmountable odds
Posts: 141
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Post by ronm on Feb 27, 2008 11:42:31 GMT
very helpful, thanks
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Post by blinda on Feb 27, 2008 16:35:19 GMT
Sorry it’s taken me a while to respond. Seeing as it was me that brought it up…..thought I’d better put in my tupence worth. As ever, Roberts’s description of testing the tension of the medial band of the PF (windlass mechanism) by the Jacks/Hubscher manoeuvre is clear and helps us to see that any slackness or late tightening of the band can hinder recovery from pronation.
As a student, and a recent one at that, it was demonstrated to me by a number of pods that the Jacks test can provide a semi quantitive scoring system for FHL, which should be done first WB without orthoses then WB in orthoses. It should be easier to dorsiflex the hallux with the orthoses, for your prescription to potentially benefit the pt. The scoring is; 0).Unable to move hallux 1) hallux dorsiflexion only 2) hallux dorsiflexion and arch rises 3) hallux dorsiflexion, arch raises and leg externally rotates.
I was told to try and get the arch to rise easily, ideal score 2-3, but avoid allowing too much external leg rotation, as this indicates supinating the pt too much.
My simple biomech assessment is done in 3 parts;
1) Foot morphology assessment (mixture of sitting & prone, to assess structures) 2) Standing assessment (muscle firing and structures on WB) 3) Gait assessment (dynamic muscle firing, but don’t have enough room to do this satisfactorily, hence interest in Tekscan)
HOWEVER; Since attending Kirbys summer school last year (hard going) I also think of the Jacks test as assessing when/if the Medial band of the PF constricts, as Robert stated. The pulling force on the medial calcaneal tubercle and the prox phalanx of the hallux produces 1st ray plantarflexion and increased supination force on the STJ. Any interruption of these can be rectified, sometimes, by RF posting and improvement seen by reapeating Jacks test with pt standing in orthoses.
`Feet which have medially deviated STJ axes and low medial arch height will show little to no STJ supination during the Hubscher test` (Kirby 1997)
Hope that makes sense….Robert, please explain how (and where to put) the plantar fascial groove to avoid aggravation / tension from the insole, in KISS terms.
Cheers, Bel
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Post by robertisaacs on Feb 27, 2008 18:20:23 GMT
Bel Could'nt have put it better myself. Well, i did'nt did i? A very full and accurate description. The PF groove is simplicity itself with the aid of the biomechanists best friend, the tool of a thousand uses, the humble lipstick. Available from all good retailers for £4.99 or from wilkinson for £1 a pop. It goes like this, in KISS terms. 1.Find out if the foot is one of them wot has a sticky outy plantar fascia. 2. Make the Plantar fascia sticky outy. 3. Draw on the sticky outy plantar fascia wif your lipstick. 4. The lippy then comes off on your foam / POP in exactly the place you want it (sorry the bad english had to stop, it was causing mental cramp.) Because i use foam i just depress the foam to the required depth on the marked area with my finger. Dent in foam = bump on cast = dent on insole. With POP i would renew the line on the -ive before filling (so it comes off on the + ive) then build a "slug" where i wanted the groove. If lip gloss ever comes big and lipstick vanishes i'm sunk! I'll have to take up high risk work instead. Regards Robert
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Post by ianl on Feb 27, 2008 18:58:57 GMT
Hi
Have to say that I rarely use the Jacks test unless the soft tissue feel, indicates a checking out of the fascia tension, however, certainly found that practicing soft tissue work over time tends to give you a feel of the nature of the soft tissue structures. Perhaps, to my shame, I have never used a plantar fascial groove although I can see why people may do. There again the absence of its use does not appear to have hindered resolution of the foot problems I've addressed (probably many I have not seen). I am sure these are all useful extra armamentaria for the tool kit but, just to be a little stirrer, do they serve more the purpose of making us feel we know what we are doing?
Ian
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Post by robertisaacs on Feb 27, 2008 20:03:22 GMT
Another good question WHICH SHOULD BE ASKED ON THE BIOMECHANICS DISCUSSION BOARD!! Robert
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Post by blinda on Feb 27, 2008 20:15:22 GMT
Cheers for that Robert, lipsticks and slugs, huh? Who says biomech equipment is expensive! Will try that with the foam. I haven`t used or seen anyone else use foam, any chance you could bring some and demonstrate at the next meet?
Keeping it Simple, Bel
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Post by Admin on Feb 27, 2008 20:22:08 GMT
I agree with Ian. Never used the Jacks Test, Hubscher Test, or used PF grooves in orthoses - still seem to get results. Blinda - two things worries me (well, a few more than two, but the rest are nothing to do with Podiatry ) - 1. That some of the stuff you are studying in biomech is complicated, when biomech is not, and 2. This statement from your post above - "Feet which have medially deviated STJ axes and low medial arch height will show little to no STJ supination during the Hubscher test` (Kirby 1997)". Is there a reference to show that this is actually the case? - I would want to see a good, robust study carried out on a biggish sample to be convinced (about the deviated axis rather than the low arch). A test by any other name...I have a ref for a test called "the great toe extension test". This seems to be the same test, but used to define/diagnose paediatric flat-foot. The authors are looking for two distinct signs which they say represents normal, the absence of either denotes problems. I guess this could be used for adults too. Have the pt stand with feet slightly apart and weight evenly distributed between them. They must look straight ahead and have their arms by their sides. Deviation from this position can evidently significantly alter the results - no data presented to support this though. If, when the great toe is passively extended the arch raises and the lower leg outwardly rotates, all is normal. I believe, in the absence of any research to the contrary (unless there is some I'm not aware of) that this is probably as much as can be accurately determined by this test, whether used for paeds or adults. Anyone want to say different? That ref. Rose GK, Welton EA, Marshall t. The diagnosis of flat foot in the child. J Bone and Jt Surgery. 67B. 1st Jan 85. Cheers,
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Post by Admin on Feb 27, 2008 20:27:50 GMT
Another good question WHICH SHOULD BE ASKED ON THE BIOMECHANICS DISCUSSION BOARD!! Robert Quite right - I'll move this section tomorrow.
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Post by blinda on Feb 27, 2008 21:27:02 GMT
Hi David,
I agree, the biomech stuff that I have been looking at since graduating is way too complex. Much of the content at Kirbys Summer School flew just a few inches above my, not so physics orientated, head. But I did pick up some gems too. Other CPD seminars have helped to simplify much of the thorny matter, which has proved biomech to be, as you say, not complicated.
The quote "Feet which have medially deviated STJ axes and low medial arch height will show little to no STJ supination during the Hubscher test` (Kirby 1997)" was taken directly from one of Kirbys Newsletters; Foot and Lower Extremity Biomechanics: A Ten Year Collection of Precision Intricast Newsletters. Precision Intricast, Inc, Payson A Z 1997, pp 143-144
As you know, Kirby has undertaken studies which indicate that a medially deviated STJ axes is associated with prolonged maximum pronation and hindrance in resupination, but I cannot find one (other than the above newsletter) which suggests that the Hubscher test can define inability to supinate, sorry. I would appreciate anyone informing me if there is one.
The `great toe extension test` does indeed, appear to be a similar, if not the same assessment. I was previously told that this can determine Functional Hallux Limitus and/or apparent flat foot. It is also true that if the pt takes a sneaky peek (not looking straight ahead) whilst you are trying to dorsiflex the hallux, the results are completely skew.
Cheers, Bel
PS. Whilst ploughing through Kirbys Newsletters, I stumbled upon....Evaluation & Nonoperative Management of Pes Valgus; Planal Dominance! So, not all feet have similar angular relationships with the STJ & MTJ axes..... Will read on tomorow, becomming clear as mud now!
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Post by ianl on Feb 27, 2008 22:41:42 GMT
Hi Bel
I suspect that the "great toe extension" may well have been the precursor of Jack's. Then possibly repackaged as Jack's as people found a specific way to use it in assessing a specific component of foot function. I was certainly aware of it before I came to realise that when people spoke of the Jack's test they were meaning the same thing. This "discovery" that sometimes occurs in all therapy disciplines can sometimes simply be a "rediscovery" with a new name attached, or, it becomes synonymous with its new proponent.
Equally I suspect that in Pod mechanics, like many other therapies, certain approaches are vogue for a while, lot's of attention given to them and then they are superseded by something else. Perhaps a while later they are rediscovered with a slightly different application but their original application and vogueness (have I just made this word up?!) is lost to history. Talk to older physios about the emphasis a short while ago on upon fascial approaches in treatments and they may often smile. The techniques are likely similar to what they did before it was given a name!
There is much about the biomechanical function of the human system that is truly complex but the intervention need not be and this is the point that confuses people at times. Can something so simple be applied to something so complex. Previously it was complex rotational motions in various planes that we had to really grasp in order to be good biomechanists. Now it is more about Axes and forces and the need to be able to think in bioengineering terms. Ironically which ever approach is taken our intervention remains broadly simlar and can be broadly simpler than we sometimes acknowlege. Some of this goes back to Brian's post in another thread, which I have not replied to yet.
Apologies for the incoherent rambling. Have just enjoyed a lovely Indian meal out and a few beers and so am not safe to communicate on forums and probably make even less sense. May well regret the post in the morning!! Ian
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Post by blinda on Feb 27, 2008 23:13:43 GMT
Hi Ian,
This is something that i need to keep reminding myself. I must confess to confusing myself when investigating non pathological A & P and applying biomech theory.
This is what i like about tissue stress theory, it makes sense to me, more than trying to normalise a foot.
Your post wasn`t rambling at all, quite reassuring in fact! Now Indian, that is a good idea for the TT2.
Cheers Bel
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Post by robertisaacs on Feb 28, 2008 8:48:04 GMT
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