The correct placing of a Metatarsal pad/dome

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I have read a thread in here about the placing of the metatarsal pad in FO. It seems like the trend is to glue prefab pads on to custom / or prefabricated components.

Whether your casting technique uses plaster of paris, a foam box or gluing prefabricated pads, the correct placing of the metatarsal head is crucial in order to relieve pressure from the MTP heads.

If one draw a straight guideline from the base of MTP 1 and 5, the MTP heads makes and arch anterior the the guideline.

My question is; How many mm anterior to this guideline should the peak of the metatarsal pad be placed in order to give the best pressure relief?

 

I'll just pick up on that comment. It is probably crucial for placement to reduce plantar pressures if higher plantar pressure have been demonstrated to be the cause of the problem being treated. .... I not that convinced that plantar pressures are the problem.

Met pad or domes have potentially many other mechanical effects in addition to the plantar pressure relief that could easily account for their mechanism of action:

eg - they probably allow for greater first ray plantarflexion --> greater first met head taking load and also easier for the windlass mechanism to work

eg - they possibly keep the plantar fat pad more under the met heads and this could allow for better coping with shear stress (though this could also decrease plantar pressures)

eg - they are probably going to inhibit the reverse windlass mechanism and this probably inhibit the tension load in the plantar capsular structures

eg - spread met heads to relieve nerve impingement (it may well be that the placement for the pad to achieve this may or may not be a different palce needed if you want to reduce plantar pressures)

 

A met dome has many uses: To extend retracted toes, to to reduce compression on a plantar interdigital nerve, to attenuate plantar force or pressure under a met head. so place the met dome in the position where it works best to achieve your goal for the individual at hand.
If I'm making a bespoke FFO then I take a w/b podtrack print and match to the Amfit scan to estimate the position of a met dome milled into the device then if needed I add poron over the top to fine tune the pressure/ comfort and position.
From clinical experience and using a pressure plate to evaluate the intervention, I have found that if you want to reduce pressure under a met head then using a moulded silicon toe prop under clawed/hammered/retracted toes in conjunction with a met dome works very well. A met bar with a large drop off can work even better but this has already been discussed in the threads mentioned above.

Dave

 

Just to add on from Craig's and David's good comments...

I personally subscribe to Spooners philosophies on foot orthoses as outlined here: http://fas.sagepub.com/content/5/5/334.full

When considering the best way to manipulate reaction forces at the foot-orthosis interface to achieve a positive outcome, decisions are made which inevitably will alter either (1) the load/deformation characteristics (stiffness) of the device, (2) the frictional characteristics, or (3) the geometry or surface topography of the device. N.B. A metatarsal dome will, to my mind, primarily influence the latter of these 3 variables.

Simon talks about how orthoses 'work' and suggests that they can only work by virtue of altering the reaction forces at the foot-orthoses interface in one of 3 ways:
* Magnitude
* Vector
* Temporal patterns

Taking all is into consideration, for any given patient with any given pathology, my first objective is to try and consider what I want to achieve with orthosis intervention. I then try and utilise my current understanding of how changing one or more of the first set of three variables mentioned 2 paragraphs above may influence the potential changes in the reaction forces listed in the previous paragraph above.

If by changing the surface geometry of a device (with a met dome) there are changes in the reaction forces which facilitate a positive outcome and help me achieve my treatment goal then bingo. I suspect the exact placement of the met dome would subtlety alter these reaction force changes, but whether that results in a clinical 'failure' will vary (read Simons thoughts on positive orthoses solution sets and zones of optimal stress). I have my suspicions met dome placement has far more to do with patient comfort/tolerance than most other things, and this in itself may be subject specific.

For the record I personally give very few met domes out whether issuing prefabs or custom devices. Only really replied as I have time to kill while I wait for Peep Show to start at 10pm... But hope my waffle is of mild interest.

Can't stress enough how worthwhile it is reading the article I have linked to above. Some great stuff in there from Simon, and also from Kevin too.

 

Thank's everyone for the informative comments. I'm aware of the many uses of a metatarsal pad. I have read all the threads that have discussed met-pads on this site, and it strikes me that only Kevin Kirky mentions the placing of the pad (... the pad is positioned with about 15 mm of the pad anteriorly hanging off the anterior edge of the orthosis plate), which is as important as why we prescribe met-pads.
Im still left with my question unanswered..

Hypothesis: If you are in a situation where you haven't met nor palpated the patients feet. Someone hands you a foam box with the contours of a foot, and a sheet with an ink-imprint of a foot. The patient needs a met pad (the diagnose, hight- and width of the med pad are subordinate). The MTP joints follow a normal arch on the ink-paper. Where are you placing the met pad?

The P&O / my colleagues, all have different meanings about this specific topic.
1) Some place the met-pad 6mm proximal to the MTP heads.
2) Some placers them distal to the MTP (because the foot tends to slide forwards in the shoe during gait.
3) And others place them way proximal to the MTP ( due to comfort of the patient ).

 

After 27+ years of trial and error of using metatarsal pads (that's what we call them here in the USA), I have found that most patients prefer to have the metatarsal pad added proximal to the area of pain so that the distal edge of the pad hangs about 15 mm past the distal edge of the orthosis plate. The apex (i.e. thickest part) of the metatarsal pad is centered just proximal to the area of maximal tenderness. I use metatarsal pads to treat patients with symptoms including plantar plate injuries (i.e. metatarsophalangeal joint capsulitis) and intermetatarsal neuromas. Two or three times a year, I may also include a metatarsal pad to the orthosis just because the patient "prefers" metatarsal pads on their orthoses since they had liked them before and want them again on their orthoses that I am making for them.

One helpful pearl on using metatarsal pads is to, on the initial application of the metatarsal pad to the orthosis, outline the proximal border of the metatarsal pad on the orthosis plate with a ballpoint pen so that the patient and I can have a reference position as to where the metatarsal pad started on the orthosis plate. Then I tell the patient to experiment with moving the pad medial, lateral, anterior and/or posterior on the orthosis plate until they fiind the most comfortable and therapeutic position for the pad over the next few weeks until their next orthosis follow-up appointment. In approximately 75% of cases, when the patient comes back to my office for their orthosis followup visit, they end up with the metatarsal pad in the exact location where I intitally put it on the plate (i.e. 15 mm distal to the orthosis distal edge).

In addition, I often will start with a slightly larger pad than what I think I may need so I can grind it or modify it into a thinner shape that is more comfortable for the patient. However, I use metatarsal pads on only about one out of 20 custom foot orthoses that I dispense in my practice, in other words, about 4 metatarsal pads per month.

Here is an illustration of how I use a metatarsal pad along with a forefoot extension of 1/8" korex for plantar plate injuries to reduce the ground reaction force plantar to the affected metatarsophalangeal joint. This orthosis modification is extremely valuable for symptomatic relief of chronic plantar plate tears.

Hope this helps.:drinks

 

That can only be decided functional foot type specific.
What works for a flexible forefoot FFT wound be awful for a rigid forefoot FFT and disastrous for a flat forefoot FFT.

Dennis

 

Hi Kirby,
I agree that the metatarsal pad should be placed proximal to the area of pain in order to spread the metatarsals, push the plantar fat forward under the MTP heads that combined with a number of other factors (some of which Mr. Payne mentioned) will relieve the MTP heads.
Your drawing is very illustrative and useful if, and only if you happen to work in a practice where FO made of prefabricated components were prescribed.

Not saying that FO made of prefab-components are worse or better than others, but to bring this thread up to a level so that all practitioners can apply in practice, I would like this discussion to be about the placing of the metatarsal pad in relation to an anatomical landmark rather than an edge on a plastic component (the edge of the orthosis plate..) of an unknown manufacture.
Btw. the metatarsal pad shown on your drawing seems to be placed in conflict with the 1st MTP-head...

Kind regards,
BionicMan

 

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How many mm should the metatarsal pad be placed proximal to the metatarsal heads?

Regards,
BionicMan

 

Hi Bionic:

If you want me to continue this discussion with you then please give me your real name and please tell me your profession (podiatrist, orthotist, orthopedic surgeon?) and, then possibly I will take the time to respond to your statement/questions.

 

I am born and raised in Denmark. My name is Mads, and I did my bachelor in prosthetics and orthotics. in Sweden. I graduated in june and I'm currently a trainee in Norway. My passion and the reason I got into P&O is prosthetics. And that's what I'm going to specialize in.

Many my colleagues have different meanings about the location of the met pads and some tend to use them for almost everything, which I am against. I know you have a life long experience with this topic and I have the deepest respect for your work and the knowledge you contribute with to this site and the field in general.

Kind regards,
BionicMan

 

Nice to meet your acquaintance, Mads, and welcome to Podiatry Arena.:welcome:

In answer to your previous question, I have found that the metatarsal pad apex (apex = thickest part of metatarsal pad) will generally be located about 5 mm proximal to the point of maximum tenderness for plantar plate injuries. For intermetatarsal neuromas, the apex of the metatarsal pad is placed directly under the metatarsal necks.

If the pad in my drawing was "in conflict with the first metatarsal head", then I wouldn't put it there since the patient would complain to me about it and then I would move it laterally. Putting metatarsal pads onto prefabricated or custom orthoses is part science and part trial and error...and will likely continue to be so for many years to come.

Good luck with your training.:drinks

 

Nice to meet you too and thank you for both your answers.

;


I'll share this with my colleagues tomorrow.

I'm sure we will cross paths on the site again in the near future.

:drinks

BionicMan

 

Bionic Man = Mads Troelsen.......for all of you who, like me, want to know who you are sharing dialogue with here on Podiatry Arena.

 

Bean meaning to ask this for a while.....

Does the suction effect that exists to stabilise joints like the shoulder and hip joints occur to a lesser extent in the MTP joints? By this I mean the stabilising effect formed between congruent joint articular cartilage, capsule, synovium or labrum etc that applies a suction cup effect to the joint by controlling the volume of fluid in the cavity?

If so...... Could a metatarsal dome pad also help maintain a more congruent joint position to aid this suction effect between metatarsal and proximal phalanges?


Conversely, is this suction effect lost with plantar plate ruptures or capsular damage that alters the volume of fluid at the joint cavity?

I ask as someone who has done some dissection work but no surgery on living patients!

 

Hey guys.. sorry if this is a little old this thread to be posting on ***came about this forum after searching for just this.. anyway does anybody know whether you can put metatarsal pads in with orthotic insoles on the same time? thanks

 

In my language, isolated metatarsal pads are accommodative. They reduce pain and allow performance while not addressing underlying biomechanical pathology therefore allowing the persons biomechanical deformity, degeneration and performance issues continue to progress. They are a band-aid.

I believe that we should seek treatments that are corrective in nature.

For hundreds of years, surgeons cut off the medial eminence (bump) from bunions as a bunionectomy. That is a met pad surgery.
A closing base wedge osteotomy, reverdin, austin is on the other hand, a corrective surgery that is corrective.

I use one or the other and not both and corrective is my goal, until that is proven unacceptable.

Dennis

 

After reading this though about metatarsal pads and metatarsalgia isnt it best to wear them in order to prevent ijury rather than a way to stregthen the metatarsal? as like all tissues they weaken with age.. even pro atheletes can get problems and pain...?

 

They should be placed right below the metatarsal heads, so below where your toes connect with your feet. I recommend the ones that don't wiggle around too much. Check out some of these met pads over at thereviewgurus.