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.

Pes cavus & pronation?? Help with orthotics prescription please.

Discussion in 'Biomechanics, Sports and Foot orthoses' started by PCore, Jul 21, 2011.

  1. PCore

    PCore Welcome New Poster

    Members do not see these Ads. Sign Up.
    Having a very hard time with a "problem" patient. She has pes cavus (bilaterally) with a semi-rigid to rigid plantarflexed 1st ray, hallux abductovalgus, and retracted toes 2-5. In weight-bearing stance the anterior view would appear as if she is a classic supinator as I expect to see with this cavus foot. But, from the rear her calcaneus is everted with 4 degrees of valgus in neutral and 7 degrees of valgus in relaxed stance. Measuring her forefoot was very tricky (more than than usual with a PF 1st ray) as I usually reduce the plantar flexed 1st ray to measure it. She was rigid enough that I couldn't do that. After second guessing (even a 2-5 varus), I measured a 2-5 forefoot valgus (2-3 degrees), which is more what I expected with the cavus. Her plantar callus pattern, though, also shows medial shearing, with calluses on the medial aspects of bilateral 1st met heads and on the medial hallux on one foot-- more indicative of pronation problem. The other foot had a callus on her 5th met head, not on the 1st. Mid tarsal joint is rigid in PF, so in gait she excessively dorsiflexes her toes to clear the ground.

    Has anyone else seen this type of presentation? I am stuck here trying to decide on what to do on her prescription for the lab and not sure what to do. Typically, I would post laterally for excessive supination with a pes cavus foot. But, this one is stumping me. Should I post the rear foot at all? If so, it would be medially. And, forefoot-- a 2-5 valgus/lateral post with a 1st ray cut-out? An arch fill would likely be necessary as my lab tends on molding the shell lower than the actual arch height. I will definitely get a deep heel cup to control the calcaneus and because these are strictly for athletic shoes. I'm guessing a semi-rigid/semi-flexible device would be appropriate.

    Any help would be greatly appreciated.

  2. Hi Kathy:welcome: to the arena

    What your discribing is late stance pronation from peroneal muscle contraction and quite common with the foot type you describe.

    The most important information you left out - what tissue are you attempting to reduce loads on, ie where is the pain ?
  3. This is a classic example of why STJ Neutral Theory shouldn't be taught to students...it is too confusing. Approaching a patient like this using the tissue stress approach would definitely make the clinical answers much more clear for this clinician.
  4. Griff

    Griff Moderator

    Hi Kathy,

    As Mike has asked: what are your patients symptoms?

    What is your diagnosis, and as such, what are you trying to achieve with your intervention? i.e. Why are you prescribing orthoses?
  5. efuller

    efuller MVP

    Hi Kathy,
    You have wandered amoungst a group of podiatrists who don't necessarily use the Root, Orien Weed clasification system much. This patient is a classic example of why we don't. That classification divides the forefoot from the rearfoot and has trouble putting it back together. Also accurate heel bisection is a problem as a line on the skin can move relative to the bone.

    One test to do to separate the pronators from the supinators is to palpate the location of the STJ axis. Those with lateral axes are more likely to be supinators and those with more medial axes are more likelly to be pronators.

    Forefoot to rearfoot relationship is very inaccurate measurement. You're not the only one who has a hard time reproducing it. However, the effect of intrinsic forefoot posting is important in the finished orthotic. I use a measurement that I call maximum eversion height. In stance, ask the patient to evert, without moving their legs in the frontal plane. Measure the height of the lateral forefoot off of the ground. Do not make an intrinsic post higher than that height. This measure combines the forefoot and rearfoot together to give you a sense of why there might be high pressure in a particular location.

    You will often see claw toes in cavus feet. When I write a prescription I decide what anatomical structure I want to reduce stress in (usually the one that hurts) and then design the orthosis to do that. The reason that you have not got many suggestions is that you have not said what hurts.

  6. RobinP

    RobinP Well-Known Member

    I completely agree. I think the way we think about biomechanics now makes learning sub talar neutral theory a disadvantage.

    I see it as being analagous to learning a foreign language. Frequently on this forum, cases are presented using sub talar neutral theory as the base for explanation. For someone who has learned sub talr neutral theory, any other explanations require "translating" in to sub talar neutral language until such times as being able to think in terms of forces and mechanics.

    If I speak French, I translate into English, formulate an answer that I then translate back into French. Given enough time living in France, I, like most people who don't use their first language in their everyday life will probably start to think in French without havging to translate.

    My understanding of sub talar neutral theory was always sketchy. Partly, inadequate reading and studying, partly a problem in its applicability to all situations( ie I couldn't apply it to all people and still treat their symptoms). I'm pretty sure it is the main reason why learning about forces and kinetics was such a Eureka moment.

    I wouldn't have a problem teaching sub talar neutral theory, I just don't think it should form the basis for the majority of institutions who teach people with the capacity to prescribe orthoses.

    Sorry not really on thread, I know.

  7. PCore

    PCore Welcome New Poster

    Thanks for your replies. She has pelvic and abdominal symptoms, actually. I'm a pelvic physical therapist, who very much uses a biomechanical approach to treating my pelvic patients. Her pelvic alignment is consistently off, despite all the soft tissue work and manipulative therapy. Specifically her left side (ASIS, PSIS, iliac crest) is typically always lower than her right. The left side is the one that is more pronated and thus effectively shortening that side in stance. I can get her back in alignment in treatment, but she always comes back out of alignment. Naturally, I look from the ground up and her foot/ankle posture is very likely contributory to her pelvic alignment and symptoms in the closed kinematic chain. Thus, the orthotics. But, as I said, this one is really stumping me.

    Any ideas??

  8. Lorcan

    Lorcan Active Member

    Hi Kathy

    I would cast in neutral making sure to capture full plantar flexed 1st ray. Get lab to make orthotic with forefoot valgus intrinsic post balanced to 0 (usual max control i find for this is about 10-14 degrees). Rearfoot post 3 degrees and if this makes patient unstable reduce it to 0. Forefoot extension with kinetic wedge.

    Just my opinion...use tissue stress.

  9. efuller

    efuller MVP

    I don't understand balance to 0. Do you mean balance the heel bisection perpendicular to the ground or do you mean 0 degrees of intrinsic post?

    By rearfoot post do you mean balance the heel bisection 3 degrees inverted or with a 3 mm medial heel skive or 3 degree heel skive or 3 degrees of motion in the rearfoot post of the device?


Share This Page