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Monday, April 11, 2011

Top 100 Biomechanical Guideline #44: Understand the Damaging Effects of Forefoot Varus Support

The cast above show the typical Root Balance Technique of  Forefoot Varus Feet. With this foot type, the maximum support is under the first metatarsal. Remember you need first metatarsal plantar flexion for normal propulsion. Having possibly too much pressure under the first metatarsal can:
  1. Dorsiflex the First Metatarsal with gradual development of bunions or hallux limitus/rigidus
  2. Dorsiflex the First Metatarsal causing Apropulsive Gait (not allow normal first metatarsal plantarflexion.
  3. Dorsiflex the First Metatarsal causing Sagittal Plane Blockade with Hip/Low Back Problems
  4. Dorsiflex the First Metatarsal producing Lateral Instability with compensation.

1 comment:

  1. Email Received 4/12/11

    Hi Rich

    More questions!

    The Prolab group of Podiatric Biomechanicanists advocate reducing forefoot varus during casting to remove the need for varus posting.

    Do you agree with this?


    Dear Lawrence, Your question is right on to my post on the problems with forefoot varus corrections done with the pure Root Balancing Technique. To my understanding, Pro Lab advocates gentle pressure on the top of the first metatarsal to remove some or all of the forefoot varus while casting the foot. To do so you will plantarflex the first metatarsal and slightly raise the medial arch. I personally have no problem with the technique. It seems to be in the right direction since most labs just fill in the arch instead of following the pure Root concept. I have always preached using the inverted technique if the forefoot varus was over 5 degrees to transfer the support proximal to the first ray. Perhaps, this ProLab modification with a slight Kirby skive will be an easier technique to get the same pronatory support without jamming up the first ray. When measuring the forefoot varus prior to casting, you should be able to have your initial measurement, then a second measurement with provocation. Let's say you measure 10 degrees forefoot varus, then plantarflex the first met gently and remeasure. I would subdivide the groups 4 ways: 0-3 degrees change (probably standard and ideal), 4-7 degrees change, 8-10 degrees change, and greater than 10 degrees change. The researchers should then look into the orthotics in these 4 groups. I know it is alot, but this is the first major change in our gold standard of casting that I have heard that has alot of merit, and should be researched. I hope this helps. Rich


Thank you very much for leaving a comment. Due to my time restraints, some comments may not be answered.I will answer questions that I feel will help the community as a whole.. I can only answer medical questions in a general form. No specific answers can be given. Please consult a podiatrist, therapist, orthopedist, or sports medicine physician in your area for specific questions.