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Who Developed the Medial Heel Skive?

Discussion in 'Biomechanics, Sports and Foot orthoses' started by Jeff Root, Oct 10, 2009.

  1. Jeff Root

    Jeff Root Well-Known Member

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    Some months ago I was sent an interesting article that to the best of my knowledge, provides us with the earliest written description of the technique that we now call the "medial heel skive" technique. The article titled "An Effective Orthotic Design for Controlling the Unstable Subtalar Joint", J. Martin Colson (may have been misspelled and should have been Carlson?) and Gene Berglund appeared in Orthotics and Prosthetics, Vol. 33 No 1 in March of 1979. Here is a section of the article that describes the technique:

    Perhaps the most important step in cast modification is exaggeration of the posterior aspect of the longitudinal arch (fig. 5) and blending this in with the medial support area above the calcaneal tuberosity (fig. 6). At this state the markings located on the navicular and calcaneal tuberosity become very important. It is between these two features that it is necessary to remove plaster aggressively in order to create the pressure needed to support directly under the calcaneus in the area of the sustentaculum tali (fig. 7). The amount of plaster removed depends on the size of the foot and the thickness of the subcutaneous tissue. It is not uncommon to remove plaster to a maximum depth of 0.8 cm. (1/4 inch) on the model of a juvenile foot."

    I have attempted to attach a pdf scan of the article. It is important to note that the authors were not using a neutral, non-weightbearing casting technique and may have been using this technique to compensate for the loss of plantar contour of the foot due to their choice of casting technique. Is anyone aware of an earlier written description of this heel skive technique?

    Jeff Root
  2. Jeff Root

    Jeff Root Well-Known Member

    Here is the pdf that I tried to upload.

    Attached Files:

  3. Jeff,

    Thanks for sharing this paper with us. So far I've only quickly scanned the paper but I think you are correct in the assumption that because they were effectively using an everted ("inward rotation of the foot"), semi-weightbearing cast what they are firstly describing here is a way to balance the cast to vertical, not by adding plaster to the forefoot and creating a forefoot balance, but rather by removing plaster beneath the metatarsal heads and heel such that the heel is "flattened precisely perpendicular to the vertical". In the case of an everted cast, this would effectively create a lateral skive on the heel and forefoot- without further modification this would result in an orthosis with intrinsic valgus rearfoot and valgus forefoot posting- not necessarily what you want in flat-foot!

    They then state that in severe deformity it is advisable to flatten the heel at "a slight angle (4-7 degrees) by removing plaster on the medial side" I'm not sure from my initial reading of the paper whether this is in addition to the skive to bring the heel to vertical or whether this is the skive to bring the heel to vertical. In the case of it being the latter, it is at odds with their everted casting technique and would create further eversion of the heel section of the cast and should surely preclude the heel being "flattened precisely perpendicular to the vertical". If we assume then that this is performed in addition to an initial lateral skive that should be necessary to bring the heel of an everted cast to vertical, what we are going to end up with is either a heck of a lot of plaster being removed from the heel section of the cast to provide us with a plantar heel contour that is varus across it entire width (as the pictures seem to be suggesting) or a "v" shaped plantar heel contour. Now depending on how much plaster was removed from the lateral side to bring the heel to vertical in the first place, a 4-7 degree medial skive does not seem very significant to counter-act their lateral heel skive, so it would need to be very deep!

    The section from the paper that you quoted above seems to me to be a way to counter-act the arch height lost by all this heel skiving and their everted casting technique. What they are basically doing is creating an intrinsic California tri-plane wedge. If they had taken a cast of the foot in a different (better) position in the first place, and inverted the cast with the balance, there shouldn't be any need to remove plaster in this area of the medial longitudinal arch.

    Interesting paper from an historical perspective. However, from recollection P.W. Roberts described an inverted heel cup orthosis in the early 1900's, which predates these guys by about 70-80 years. Regardless of the historical, I think I'll stick to the version of the heel skive techniques that I perform that are a modification of Ray Anthony's modification of Kevin Kirby's initial description, mixed with a bit of Blake, Root, et al.
  4. Attached is the original paper on casting for the UCBL.

    Attached Files:

  5. Jeff Root

    Jeff Root Well-Known Member


    The article An Effective Orthotic Design is somewhat vague about positioning of the foot during casting. In the 1969 UC-BL article that you posted above, they advocated a neutral position, semi-weightbearing casting technique. It says "The corrections attempted so far have been eversion or inversion of the hindfoot to a neutral position". Unfortunately a semi-weightbearing cast, as a result of plantar pressure, results in compression and flattening of the plantar contour of the heel and forefoot and reduces our ability to control the forefoot to rearfoot relationship because it assumes a compensated ff to rf position.

    In spite of this disadvantage, the picture (fig 3) in the heel skive article depicts what appears to be a relatively parallel relationship between the distal tibia and what would be the vertical bisection of the heel. They recommended flattening the plantar plane of the heel and forefoot to "precisely perpendicular to the vertical" but without the benefit of an actual heel bisection, this leaves us wondering where in the frontal plane the heel really is.

    There are two components to their "skive like" technique. In severe cases, they suggest creating a 4 to 7 degree angle on the plantar heel by removing plaster medially. This is an inversion or medial heel skive. The second component was the blending of this skive into the medial arch under the sustentaculum tali that I described in my posting above.

    To the best of my knowledge, this is the first written description of this type positive cast modification. There is no doubt that Kevin Kirby popularized the technique, but it seems that this modification existed prior to that. I guess it just goes to show that we are sometimes reinventing the wheel, with some modification.

    Jeff Root
  6. Indeed, it also potentially leaves us with both forefoot and rearfoot valgus skives as I previously stated. Giving the benefit of the doubt, lets say that they skive off the medial heel and forefoot. We've got real issues here with dorsiflexing the first ray with that forefoot skive. Moreover, the arch lowering that would occur as a result of skiving both the forefoot and rearfoot on their medial aspect makes their second skiving beneath the sustentaculum tali necessary.

    Correct, but as I previously said, it's suggested in the paper that they everted the cast by allowing "inward rotation of the foot". This creates the "skive balancing" issues I described above.

    There is nothing new under the sun and even Newton stated that he had benefited from the "shoulders" of others. I've spoken with Kevin about the medial heel skive technique on many occasions and he always points out the roll Rich Blake, John Weed and others had in shaping his thoughts. I have no doubt that if this paper was known to him prior to writing his medial heel skive paper he would have cited it in his paper, and discussed it with me at some stage. Indeed, until you posted it, I'd never heard of it, and I've read an awful lot of papers on foot orthoses! Some of them, just plain awful.

    While the technique described in the paper you posted above undoubtedly results in a removal of plaster from the heel and forefoot of the positive cast, it is a far cry from the technique and rationale described by Kirby. Indeed, the comparative is probably analogous to the "Levy mould" versus the "Root device".

    Finally, to specifically answer your question "Who developed the medial heel skive?" My answer is: Kevin Kirby because to the best of my knowledge he was the first to use the term "medial heel skive" in describing the modification and the technique which is commonly referred to as a medial heel skive bares the characteristics of the technique he described, and little resemblance to the technique described in the paper you referenced. To me this is like asking "who developed the Root orthosis?" and then dragging out the historical papers that contain information that could be said to bare a resemblance to your fathers work. It's gamesmanship for sure, but is it really necessary?
  7. BTW, I don't think this is a blending, from the pictures it appears they are removing a significant amount of plaster beneath the sustentaculum tali in an attempt to control the foot via orthosis reaction force in this area. To me, it looks like it would result in a pretty uncomfortable device. What I found interesting is that they recognised that pushing with the orthosis into the distal aspect of the medial longitudinal arch was a fruitless activity, yet did not attempt to define the rationale as to why this was the case. Kirby's work on STJ axis location provides the rationale for this.
  8. CraigT

    CraigT Well-Known Member

    I answer a similar way when I am asked 'what type of prescription do you usually do?':D, although I am not sure what Ray Anthony's mod is...
  9. Basically, variation in degrees as oppose to variation in depth.
  10. CraigT

    CraigT Well-Known Member

    Ak OK- I do that too...
    In addition I like to rotate the skive externally in the transverse plane to give some more sagittal plane inclination- more tri planar.

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