Welcome to the Podiatry Arena forums

You are currently viewing our podiatry forum as a guest which gives you limited access to view all podiatry discussions and access our other features. By joining our free global community of Podiatrists and other interested foot health care professionals you will have access to post podiatry topics (answer and ask questions), communicate privately with other members, upload content, view attachments, receive a weekly email update of new discussions, access other special features. Registered users do not get displayed the advertisements in posted messages. Registration is fast, simple and absolutely free so please, join our global Podiatry community today!

  1. Everything that you are ever going to want to know about running shoes: Running Shoes Boot Camp Online, for taking it to the next level? See here for more.
    Dismiss Notice
  2. Have you considered the Critical Thinking and Skeptical Boot Camp, for taking it to the next level? See here for more.
    Dismiss Notice
  3. Have you considered the Clinical Biomechanics Boot Camp Online, for taking it to the next level? See here for more.
    Dismiss Notice
Dismiss Notice
Have you considered the Clinical Biomechanics Boot Camp Online, for taking it to the next level? See here for more.
Dismiss Notice
Have you liked us on Facebook to get our updates? Please do. Click here for our Facebook page.
Dismiss Notice
Do you get the weekly newsletter that Podiatry Arena sends out to update everybody? If not, click here to organise this.

Orthotic prescription advice needed.

Discussion in 'Biomechanics, Sports and Foot orthoses' started by Berms, Dec 11, 2007.

  1. Berms

    Berms Active Member


    Members do not see these Ads. Sign Up.
    14 yr old girl comes into the clinic with parental "concern" re: flat feet. In a nutshell, gross pronation associated with significant degree of hypermobility of STJ and MTJ's as well as rearfoot and forefoot varus. Interestingly, her feet had a relatively low arch - even in a NWB, "neutral" position (I use the term "neutral" loosely).

    Orthotic prescription included an intrinsically corrected f/f to vertical, std arch height, standard fill, medial wrap (flare) on a std grind, medial heel skive 10 deg, EVA r/f posting at 4 deg....

    The devices provided what I considered to be great results, including the reduction of her RCSP from 6 and 8 degrees valgus R & L respectively, to 0 degrees when standing on the devices (even though I know this alone is not representative of the effectiveness of a device!) BUT then I check the first ray, and I have restricted hallux dorsiflexion whilst on the device, presumably as a result of an elevated 1st metatarsal (or more accurately - the device has "blocked" the 1st metatarsal from properly plantarflexing).

    How can I achieve successful orthotic outcomes in a case like this, without elevating the 1st metatarsal and restricting its normal function?

    Thanks for any advice.
     
  2. Daniel Bagnall

    Daniel Bagnall Active Member

    Re: advice needed - orthotics provide great "control", but....

    Hello,

    Re: the cc, what were the symptoms associated with the parental concern (flat feet)?

    I'm not trying to be rude, but it does not make any good biomechanical sense to be using terminology such as "hypermobility", you should be substituting this for stiffness. In terms of "neutral", are you referring to NCSP, RCSP or SJN? Once again, the terminology you have used is inaccurate and ambiguous.

    My guess is that the devices you have prescribed are not controlling the foot enough i.e not enough varus control. Medial column instability is probably still an issue for the pt when wearing the devices, which is why you have restricted hallux dorsiflexion.

    To start with, you would have benefited from balancing the cast inverted as opposed to vertical as you are able to achieve a greater supination moment or varus control. In addition, instead of normal arch fill, I would advise minimal medial arch fill instead, as this once again, helps reduce the pronation moments or increases the amount of varus control. I am not familiar with medial heel skive's being prescribed in degree incriments, I have always prescribed in mm i.e. 2mm, 4mm, 6mm etc. I would anticipate that 10 degrees is sufficient. You haven't indicated the shell thickness you have used? A 4mm polypropelene shell would probably be sufficient, as you will probably need a device with increased stiffness. To facilitate 1st ray PF/hallux dorsiflexion, I would suggest a FF valgus post extension or reverse mortons extension which will allow the 1st ray to PF thus enhancing the windlass mechanism.

    I hope this helps :)

    Regards,

    Dan
     
    Last edited: Dec 12, 2007
  3. trudi powell

    trudi powell Active Member

    A few issues...
    1. Are you worried about the restriction of Hall movt on the intial date of fitting ?? always allow 2-3 weeks to see what is really happening, as the body will try and fight the correction initally. But 3 weeks max...then act.

    2. If the forefoot is still pronating through the orthotic you may have just missed locking the MTJ during the casting process. To fix this you need to re-cast.

    3. too much ILA fill could pronate the foot. This is all to do with the MTJ axis. To test this , get the foot into ' neutral' then apply pressure from the 1st to the 5th Met Heads ( just proximal to the Met heads is best ) with your thumb and notice if the pressure you apply has a pronating effect to the foot. Sir Craig Payne will probably tell you the actual degree of the typical axis.... but it has been too many years and too late tonight for me to tell you.... but it should be just between the 2nd and 3rd Met heads.

    4. I love the 10 deg heel skive on the hypermobile kid. It also helps take alot of the pressure off from under the navicular and therefore alot more user friendly.

    So I think you are on the right track, but somewhere along the line the MTJ isn't being controlled to the extent that you were aiming for. Position the MTJ properly and you will have what you were aiming for.

    Trudi
     
  4. Daniel Bagnall

    Daniel Bagnall Active Member

    Hi Trudi,

    I just had a few questions re: your suggestions and wasn't too sure on some of your explanations. If possible could you please try and elaborate the following...

    1. Could you please explain what MTJ locking means? I was under the impression that the MTJ works more like a spring as opposed to a locking mechanism.

    2. What MTJ axis are you referring to that runs between the 2nd and 3rd met heads? The only MTJ axis I am familiar with is the single MTJ axis proposed by Nester et al. This axis runs roughly half way between Manters 2 axis model.

    3. What does "hypermobile" mean?

    Regards,

    Dan
     
  5. Asher

    Asher Well-Known Member

    Hi Berms,

    If you have elevated the 1st ray and you want to get it down, at this poitn, you could do a 1st metatarsal cutout. To decide what level to take it back to, do the modified FnHL test - this is done nwb - I'll explain later if you don't know what I mean.

    Plus, you could also use Dan's suggestion of sub 4-5 met head padding but only if there is some range of dorsiflexion in that lateral forfoot area - to find that out you use the Lateral forefoot elevation test.

    If you had anticipated elevating the 1st ray before you casted, I would have used a minimum fill and a 1st ray wipe - a cast correction that the lab does to push up higher in the proximal MLA and then pretty much straight down to the distal medial edge.

    However, if you have a rigid forefoot varus foot type and your excellent orthotic control has actually elevated the 1st ray such that the 1st MPJ is sitting up off the floor, that's a different matter. I have a case that's somewhere here on podiatry arena I think I even posted some pictures, it might be helpful.

    Sorry I don't have time to explain further, might catch up with you later this afternoon if you have any questions that others haven't clarified for you.

    Rebecca
     
  6. Daniel Bagnall

    Daniel Bagnall Active Member

    Hello again,

    I forgot to mention, were you cautious with your casting technique i.e anterior tibial contraction. If their was any unwanted contracture, then the device may interfere with 1st Ray PF/hallux dorsiflexion mechanics. This can sometimes be corrected by bringing the 1st Ray down (or plantarlexing it) during the negative casting procedure.

    Regards,

    Dan
     
  7. Daniel Bagnall

    Daniel Bagnall Active Member

    Asher,

    Do think its possible for a 14y/o girl to have a true FF Varus deformity. Maybe it is possible, but I would beg to differ. I would have thought someone at that age would be more likely to have a supinatus (soft tissue) deformity?

    Your thoughts...?

    Cheers,

    Dan

    Dan
     
  8. LuckyLisfranc

    LuckyLisfranc Well-Known Member

    These two observations seem contradictory to me.

    On one hand you say the hindfoot is hypermobile, yet in non WB you note she has a low MLA.

    The latter screams out for excluding tarsal coalition - a (rigid) flatfoot with low MLA in non WB is a tarsal coalition until proven otherwise.

    Fundamentally, is the this a flexible or rigid flatfoot? i.e. does a 'normal' medial arch profile become reestablished with non WB or with a Jack test?

    LL
     
  9. Asher

    Asher Well-Known Member

    Hi Dan

    It sure is, infact, I received a lot of advice about orthotic prescription for a 14 yo boy with true FF varus - the thread was started by TEW and is titled "Uncompensated forefoot varus - what do I prescribe?". Sorry there are no pictures but I have just re-read the thread and its all pretty clear.

    Regards
    Rebecca
     
  10. Berms

    Berms Active Member

    Thanks LL,
    she definitely has a flexible flatfoot (not rigid flatfoot), and tarsal coalition has been ruled out. The low MLA was more a description of MLA shape/contour rather than "position" - I should have just left that bit out, it just confuses the issue and is really of no significant consequence... What is the Jack's test? Thanks again.

    Berms
     
  11. Berms

    Berms Active Member

    Thanks Asher,

    she has supinatus (not true ff varus) and I didn't anticipate elevating the 1st met before casting - but the first ray wipe and min fill you mentioned probably would have been a good option. Also, could you explain a little bit more about the modified FnHL test? Thanks again.

    Berms
     
  12. pgcarter

    pgcarter Well-Known Member

    My take on the term "hypermobility" is that it means something moves at a time when it should not, rather than meaning something has a large ROM.? Is that how others use it?
    regards Phill Carter
     
  13. Asher

    Asher Well-Known Member

    Hi Berms,

    This is straight from the notes provided at Bootcamp#4 (I hope this is OK Craig :confused: ):

    "The aims of performing the windlass mechanism test (ie: Jack's Test) are to determine:
    1. the force required to dorsiflex the hallux during static stance
    2. the timing of the windlass mechanism during static stance

    FORCE
    With the patient standing in their normal angle and base of gait, grasp the proximal phalanx, dorsiflex the 1st MPJ and estimate the amount of force that is needed to supinate the foot. This is a very qualitative test, which requires practice on a lot of feet to get a feel for the different level of force needed to supinate a foot. When you start doing this test you will notice some feet are easy to dorsiflex at the MPJ and others are very difficult. Rate as EASY / MEDIUM / HARD

    TIMING
    Repeat the movement in part one. However, this time, observe medial longitudinal force to determine whether supination of the arch is immediate or delayed ie: how much hallux dorsiflexion occurs before the arch begins to supinate?
    Also, observe the timing sequence between hallux dorsiflexion, supination of the medial longitudinal arch and external rotation of the tibia. Rate as IMMEDIATE / DELAYED"

    In regard to the modified functional hallux limitus test, while supine, dorsiflex the hallux at the 1st MPJ while putting some pressure (how much - hard to explain - not soft, not hard) under the 1st metatarsal head. If the windlass mechanism is delayed, move your (plantar) thumb proximally along the 1st ray. At some point, apparently can be back past the medial cuneiform, the windlass will establish much easier than with pressure applied more distally. That is the level to which you do the cutout.

    Rebecca
     
  14. pgcarter

    pgcarter Well-Known Member

    Or in fact just make the anterior 1st met angle of the device steep enough so that you don't need to do a cut out...works for me
     
  15. Asher

    Asher Well-Known Member

    I agree pgcarter, I prefer a 1st ray wipe as a cast modification. That way, you don't end up with a distally narrow device that sits medially in the shoe. Having said that, I have not experimented much with the cutout so I should be a bit careful in making that assumption.

    Regards

    Rebecca
     
  16. pgcarter

    pgcarter Well-Known Member

    Do you make all the things you prescribe?
     
  17. Asher

    Asher Well-Known Member

    I assume you're talking to me pgcarter.

    I don't make any orthotics I prescribe. They go to an orthotic lab to be made.

    I use a lot of off-the-shelf full length arch supports and add bits to them depending on the foot and the problem that presents.

    Why do you ask?

    Rebecca
     
  18. Berms

    Berms Active Member

    Thank you :D
     
  19. pgcarter

    pgcarter Well-Known Member

    Hi Rebecca,
    Yes I did mean you, because I think if you don't make it yourself then the level of control you have over these small variables is fairly limited. The lab devices I see in Victoria are really one product in about half a dozen flavours rather than genuinely shaped for individual feet and problems. I'm off topic and probably not going to win any friends by going on about this issue....but I think most of the profession is kidding itself about the ability to offer really tailored solutions when you order from a lab. I also think so few people have actually made enough devices to actually have much of an insight into the finer points of shape, materials choice, and tolerance that much of what goes on is fairly ineffective. How many pods do you know offering a money back guarranty? This should really be a new thread I think.
    regards Phill Carter
     
  20. Daniel Bagnall

    Daniel Bagnall Active Member

    Hi Phill,

    In an ideal setting, I would love to be making my own devices. But, I know this is not realistic, well for me anyway, and probably for others who are operating busy practices. However, I think the construction and outcomes of orthotics would be a lot more favourable, if we were doing them oursleves, as we can visualize precisely, what it is, we want to the device to do for the pt.

    BTW, if I do have a temporary orthotic failure, I offer my pts 2 choices, either a re-cast or money back. No questions asked.

    Regards,

    Dan
     
  21. Daniel Bagnall

    Daniel Bagnall Active Member

    Hi Phill,

    I originally asked "Trudy" and corrected "Berms" re: Hypermobility, as I thought the profession was moving away from using this terminology. Reason being, is that it is not quantifiable and is not scientifically accurate. I understand though, that the majority of the BMX exam is arguably subjective among clinicians, which is why terms like "hypermobility" and "MTJ locking" is still widely used.

    Regards,

    Dan
     
  22. Asher

    Asher Well-Known Member

    Yes I made orthotics for my first several years of practice. It was good to do, not saying I was the world's best at it but I learned a lot. But that was when I didn't mind working 7 days a week.

    Now I would not cut the mustard at orthotic manufacture even if I wanted to. I'm very glad to have a lab to send to. I am relatively confident in my lab, I don't mind asking questions and consulting with them and I don't mind going to the expense of having more than one go at an orthotic for a patient ie: if it didn't work or if I find I should have prescribed it differently.

    But in reality, all podiatrists making their own orthoses is just not going to happen. You need to rely on a lab and have a good working relationship with them. That's not unreasonable, I'm sure.

    Rebecca
     
Loading...

Share This Page