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1st met head Cutout. What and why

Discussion in 'Biomechanics, Sports and Foot orthoses' started by Robertisaacs, Jun 19, 2007.


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    I wish to tap the vast collective wisdom of the community.

    I have a colleague who is BIG into 1's met head cutout modifications (not 1st met, 1st met head). Uses them on almost every device he issues and has developed the habit applying it to devices i've issued whenever he sees any of my patients. I'd never heard of this one, could'nt find it in the langer prescription, Firefly do it and give some limited info here http://www.firefly.ie/html/shellmod.html. It seems to consist of snipping the distil medial corner off the orthotic.

    I'm struggling to figure out how this works and cannot find any information on the Wonderweb. The firefly website says it's contra indicated for HL /HR and good for Planterflexed 1st ray. I cannot see how this works, if the peak height of the device is unchanged and the met head was previously over the end of the orthotic (i tend to stop pre met) and if only the corner of the distil end is removed how does this allow the 1st ray to planterflex?

    Does anyone use this modification?
    Can anyone explain how it works?
    Why the contra indications?
    Has any research been done on it?

    Thanks in advance

    Robert
     

    Attached Files:

    Last edited: Jun 19, 2007
  2. Craig Payne

    Craig Payne Moderator

    Articles:
    8
    Re: Ist met head Cutout. What and why

    I have a problem with anyone who uses the same type of orthotic or orthotic modification on everyone.

    From our experiments (just playing before doing formal research), most first met head, first ray, etc cut out's dont work because they are never big enough.
     
  3. Johnpod

    Johnpod Active Member

    Re: Ist met head Cutout. What and why

    Hi Robert

    Surely 1st met head cut-out and 1st ray cut-out are the same thing, differing only in degree, where the medial side of the shell is cut away to make room for the 1st met. All shells should finish behind the met heads as you observe and if they dont you have a gait plate that prevents movement at the MTPJs.

    The aim, of course, is to allow the 1st ray to plantarflex relative to the second ray - and can only have effect if there is a forefoot varus posting (intrinsic or extrinsic).

    This would accommodate a fixed 1st met plantarflexion and allow functional movement of a flexible 1st met plantarflexion whilst supporting a varus forefoot 2-5. In my experience the cut-out needs to be close to one third of the shell width at the distal end.

    Totally agree with Craig that this should not be necessary in any but those cases that need it. Anyone doing this in every case demonstrates a real lack of biomechanical understanding of 1st ray function.

    'If I have seen further than most it is because I have managed to see round the big beggars in front'
     
  4. Admin2

    Admin2 Administrator Staff Member

  5. Re: Ist met head Cutout. What and why

    Thanks guys.

    Apparently not! (and don't call me Shirley ;) ). On the prescription (which is the only thing i've got to work on) they are very distinctly different. Thats what has me baffled, I can understand the concept of cutting away enough of the shell to make room for the 1st met to planterflex, this mod, however, is very distinctly only the very end of the shell for the met HEAD, (which i agree should not have any shell under it anyway!). The vast majority, I would say 80 + %, of the shaft of the met is still supported by the orthotic.

    How far up the met would you bring the shell cutout?

    Anyone got any ideas why it should be contra indicated for HL / HR?

    Regards
    Robert
     
  6. Re: Ist met head Cutout. What and why

    Ok i guess that answers the question as far as how many people use this modification, 170 odd view, 2 replys, neither of whom use the technique.

    I still can't see how it works, why it is an alternative to a 1st met cutout for a PF 1st ray or why it might be contra indicated for HL / HR.

    Oh well

    Regards
    Robert
     
  7. davidh

    davidh Podiatry Arena Veteran

    Re: Ist met head Cutout. What and why

    Hi Robert,

    I use 1st MPJ cut-outs (usually for FF valgus) but sometimes have to return my orthoses to the lab to have them enlarged (which backs up what Craig wrote earlier in the thread.

    Also, horses for courses. It is clearly not a custom device if fitted as a standard one-type-fits-all design.

    Cheers
     
  8. Re: Ist met head Cutout. What and why

    Dave

    Thanks for helping me out!

    When / with which patients do you use 1st met head cutouts in preference to 1st met cutouts or reverse mortons extensions / kinetic wedges? Why?

    Regards
    Robert
     
  9. gangrene1

    gangrene1 Active Member

    Re: Ist met head Cutout. What and why

    I've seen one of colleagues using it patients with plantar fasciitis cases. I suppose this will allow the 1st ray to plantarflex fully.No?
     
  10. Re: Ist met head Cutout. What and why

    Don't understand how! The peak height of the shell and the position of the met head resting on the ground remain the same. All you loose in, for example a size 12 foot, is 8 or 9 mm of shell under the distil end of the met shaft. If that.

    If you want to planterflex the 1st ray why not use a first RAY cutout or cast the foot with the 1st ray in a planterflexed position in the first place? I kinda feel that this mod has something different in mind but don't know what.

    Regards
    Robert
     
  11. Shane Toohey

    Shane Toohey Active Member

    Re: Ist met head Cutout. What and why

    Hi Robert,

    I'm with you on this one. You said;
    All of our podiatry jargon tends to get interpreted differently by individuals who assume that theirs is the strict one.
    Definitely, in some places there is a distinction between a first ray cutout and a met head cutout and we get asked for both.
    The met head angled section off the medial corner of the device seems to allow the device to roll easily to the medial side as the forces transfer to the forefoot.
    This will allow the met head to gain maximum ground contact but methinks that's only if the device was too high anyway. If the device is not too high in the arch the first should be able to contact anyway?
    Personally, I think some of the modifications arise because for one reason or another many devices are made with arches too high. However you want to describe it, i think, there is too much attempt to control the foot through the arch which will obviously interfere with function, when it is far simpler to modify function with rearfoot and forefoot wedging of one sort or another.
    If you want to promote the first into propulsion then you can do it by having some elevation of the shell on the lateral forfoot or having a 2-5 or valgus wedged extension on the device and making sure that the arch is not too high. I think the cut out devices become more and more unstable over time.
    Alarm bells ring when anyone says that"they do something all the time and it works" Obviously, the only thing working is their bad eye.
    I saw a tennis player recently who had such a device and had now started to develop problems with her 5th mpj as the device was everting at the forefoot and consequently lifting the fifth as it rolled.

    Cheers
    Shane
     
  12. drdebrule

    drdebrule Active Member

    Re: Ist met head Cutout. What and why

    Some orthotic labs are now making a bidirectional first ray cutout which inludes an additional cutout in the distal aspect of the first ray cutout. How exactly is this accomlished in an orthotic lab? And when does one use a bidirectional cutout as opposed to a tradional 1st ray cutout or simply casting with 1st ray plantarflexed.

    Thanks!

    Michael B. DeBrule, DPM
     
  13. Re: Ist met head Cutout. What and why

    ???????? Don't understand your description- photograph/ diagram please.
     
  14. Craig Payne

    Craig Payne Moderator

    Articles:
    8
    Re: Ist met head Cutout. What and why

    I not sure what they mean by this eaither. Is it just marketing speak? - "bidirectional" sounds impressive!
    I am of the belief that we should never need to use first ray cut outs ... by doing what you said: plantarflex the first ray during casting.
     
  15. Bruce Williams

    Bruce Williams Well-Known Member

    Re: Ist met head Cutout. What and why

    Bi-Directional Cutouts are done as follows, by me anyway!:rolleyes:

    Make your cutout of teh 1st metatersal head from 2 points, just proximal to the medial aspect of the 1st metahead and at the medial aspect of the 2nd metahead where the device ends.

    Next mark a point at the midshaft of the 1st metatarsal, or at the base of the 1st metatarsal. Then a point 1/2 way between the 2 points above as described above.

    Now, grind your cutout of teh 1st metahead as above, then grind your 2nd cutout as marked above.

    This is a bi-directional cutout that I learned from Howard. It works better than a metahead cutout, but not as well as a large J-cutout.

    Also, I would make the cutout to the base of the 1st metatarsal cun joint at the least. As Craig said, bigger is better in most cases.

    Finally I disagree with Craig on casting. If you do not increase or maximize the heght of the lateral column when you plantarflex your 1st ray in your neutral position NWBing cast, you will not get as much benefit as if you just add a 1st ray cutout alone.

    You need to stabilize that lateral colunn first, adn you will find you rarely need to PF the medial column when you do cast then.

    My data shows that a 1st ray c/o is almost always better than not having one at all, especially if you backfill with ppt or poron.

    :good:
    Bruce
     
  16. Craig Payne

    Craig Payne Moderator

    Articles:
    8
    Re: Ist met head Cutout. What and why

    What I probably should have said is that my preference is to not use them, but I end up using them a lot to get the first met head loaded adequatly.
     
  17. Bruce Williams

    Bruce Williams Well-Known Member

    Re: Ist met head Cutout. What and why

    Craig;

    Well you could have saved me a lot of typing and you a lot of reading if you had said that in the first place!:dizzy:

    :drinks
    Bruce
     
  18. drdebrule

    drdebrule Active Member

    Re: Ist met head Cutout. What and why

    Bruce,

    Thanks very much for the recipe for the bidirectional cutout. I will try it sometime.

    I fill almost all of my cutouts with PPT, which seems to make a big difference sometimes. Personally I mostly large (met-cuneiform) cutouts, a few small traditional cutouts (like on the PFOLA website), and sometimes I skip the cutout altogether. Perhaps the variety of observations and comments on this post have to do with slightly different casting techniques or orthotic labs.

    There is no established evidence based protocol yet for use of these first ray cutouts. I am still waiting for a study that looks at type of cutout ( short, long, bidirectiional), presence or absence of PPT(poron) fill, and first ray position during casting. Please send me a million dollar check and I'll get it done for you.

    Thanks!

    Michael B. DeBrule, DPM
     
  19. Bruce Williams

    Bruce Williams Well-Known Member

    Re: Ist met head Cutout. What and why

    Mike;

    if I had the million I'd be working on the study myself! :rolleyes:

    The thing about doing studies of this nature is that so much can come into play on what effects the function of the 1st ray.

    Often a heel lift can make a huge difference on F/T functions of the 1st ray on both the long limb and short limb sides.

    Sometimes manipulation of the AJ will cause significant changes.

    I think that at the least you would have to eliminate LLD changes and then treat the FnHL with differing cutouts to track what changes work.

    Finally you are correct about casting technique. That can make even more of a difference, though utilizing an OTC device w/ a properly sized 1st ray c/o makes a huge difference too.

    :drinks
    Bruce
     
  20. Dananberg

    Dananberg Active Member

    I use the following as a basic protocol for using 1st ray c/o's. Essentially, the less ROM at the 1st MTP joint, the greater the c/o size. Also, the lower the arch profile of any particular foot, the larger the cut out size. This is strictly from clinical experience and I have never formerly studied this.

    From my years of using F-scan, I have found that fairly subtle changes in cutout shape and design do affect 1st ray loading. I also use a variation between the bidirectional that Bruce so accurately described, and the larger c/o that ends just distal to the met-cuneiform joint. It is a bidirectional c/o with a fairly shallow groove along the longitudinal bisection of the 1st metatarsal. About 2 cm in length from the distal end of the orthotic shell is adequate. One would tend to think that this is insufficient to affect loading, but after measuring these with F-scan for many years, it is rather surprising how much this does.

    Howard
     
  21. drdebrule

    drdebrule Active Member

    :confused:

    Howard,

    Where is this groove exactly if your orthotic lab has just cut away most of the shell underneath the longitudinal bisection fo the 1st metatarsal? I tried to make a sketch of this and failed. Do you have a picture, that might be helpful? Is this the different from instructing your lab to make a shell groove for the 1st metatarsal head?

    Thanks!

    Michael DeBrule, DPM
     
    Last edited by a moderator: Jan 11, 2008
  22. Ezekiel

    Ezekiel Welcome New Poster

    Re: Ist met head Cutout. What and why

    Hello Robert,

    I was always of the impression that the 1st met cut out helped improve the function of peroneus longus. The cut out being about 45 degrees will cross the tendon at a right angle just before it inserts into the 1st met head thus providing an equal force across the tendon. Am I making any sense?? :confused:
     
  23. Mart

    Mart Well-Known Member

    Hi Howard

    I am interested on how you decide if the data you collect is significantly different with and without FO use, or have you simply formed some less formal semi-quantative impression?

    Are the changes you see immediate with foot orthoses use or do they occur after a period of foot orthoses use once gait patterning characteristics have adapted to the effects of foot orthoses?

    Do you examine PP, FTI's or other kinetic parameters, do you use some kind of template system to define region of interest?

    How do you deal with the problem of sensor creasing around the margins of the the cutout?

    I have been considering trying to examine this issue myself and have been thinking about the pros and cons of placement of the senor beneath the foot orthoses to avoid creasing artifacts and just measuring 1st MTH and perhaps plantar digital area 1st toe GRFs. Do you have any thoughts on this?

    A question then might be which parameters would be useful to look at, how might they be affected by covering materials and at what threshold do they become meaningful.

    I seem to recall reading a paper which you published which examined the ratio between plantar digital area 1st toe and 1st metatarsal head GRFs in relation to identifying FHL gait patterns. Since this approach normalises the data to the individual and would seem relevent to measuring changes which might effect the "3rd Rocker" and its compensations, I'd be interested in your comments.

    I use some published data which gives PP and FTI values +- 1SD for a small normal population, as a part of my data analysis protocol but this is taken from barefoot mat data and therefore not that useful for inshoe measurements.

    Are you aware of any normal inshoe data other than that which Tekscan bundles with their addon TAM software which might be usefully used for intersubject comparisons?

    cheers

    Martin



    The St. James Foot Clinic
    1749 Portage Ave.
    Winnipeg
    Manitoba
    R3J 0E6
    phone [204] 837 FOOT (3668)
    fax [204] 774 9918
    www.winnipegfootclinic.com
     
  24. Mart

    Mart Well-Known Member

    I use it if I consider the complaint is associated with abnormal 1st metatarsal head loading or some danaging compensatory pattern which has developed to reduce 1st metatarsal head loading (eg related lesser metatarsal head overload).

    My belief is that I am either reducing 1st metatarsal head loading, either directly by shifting GRF laterally or by repositioning the 1st ray during loading allowing the 1st metatarso-phalangeal joint to move without "jamming" the dorsal joint margins and increasing available ROM or allowing ROM earlier during midstance, or reducing need for compensation which is causing other problems secondarily to this or a conbination of any or all of these.

    The only evidence I have that I am accomplishing this is patient reported progress. Sometimes this will occur after modifying a pre-exisitng foot orthoses without a cutway window to first metatarso-phalangeal joint which has not worked or likewise removing a forefoot post.

    Anecdotaly I can report consistent and often suprising resolution of pain with hallux limitus (often approaching rigidus), FHL causing 1st metatarso-phalangeal joint or assumed compensatory pain, and have seen in a few patients with tramatic synovitis of 1st metatarso-phalangeal joint lose signs of synovitis with power doppler after foot orthoses use.

    Currently I am trying to design a system to support an ultrasound probe above the 1st metatarso-phalangeal joint inside a modified shoe and examine 1st MPJ kinematics during stance. The idea would be then to see if a cutway window to first metatarso-phalangeal joint influnces metatarso-phalangeal joint function in the way we might theoreticlly envision. This is a tricky job and I may be flogging a dead horse, will post some info if I have any luck.


    cheers


    Martin


    The St. James Foot Clinic
    1749 Portage Ave.
    Winnipeg
    Manitoba
    R3J 0E6
    phone [204] 837 FOOT (3668)
    fax [204] 774 9918
    www.winnipegfootclinic.com
     
    Last edited: Jan 19, 2008
  25. Shane Toohey

    Shane Toohey Active Member

    Hi Ezekiel,

    You wrote:
    I haven't found mention of PL inserting into 1st met head, only the base of it and close proximity. Was that a misprint?

    Cheers
    Shane
     
  26. Cathy Ninio

    Cathy Ninio Welcome New Poster

    I use 1st ray cut out where there is a rigid or semi rigid plantar flexed first ray with 2-5 ff varus. Allows control of ff without causing jamming of base of first ray and I would post ff 2-5 appropriately. I don't use this often but always in rigid PFFR situations.
     
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