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Please consider a donation if you feel the blog has helped you. A $5 donation will help me pay for the blog artwork, guest writers, etc. $90 has been donated in August 2017. I am very honored and grateful. Dr Rich Blake

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Sunday, December 18, 2011

When We Push Off the Ground: What is the Ideal Wear Pattern?

When we push off of the ground, the powerful first metatarsal should be free to plantar flex (move downward towards the ground) with most of the weight on the 2nd through 5th metatarsals (2nd the most). As push off continues (aka propulsion), the sign of great push off is strong wear under the hallux (big toe) itself.

In the photo above, the right foot shows the typical signs of great push off (also called a propulsive gait pattern), and the left shows minimal to no active push off (confusingly called an apropulsive gait pattern). The right side shows dramatically more pressure under the first through third metatarsals seen in a good push off.

Overall, however, the left side shows more mid foot and metatarsal area pressure, so that side is bearing more weight. These top covers were put on at the same time, and are only used for walking. The patient does a lot of walking each day.

For those biomechanical afficianodos, this patient has forefoot varus with a Root Balanced Technique. I do not like the first metatarsal pressure on both sides, and would personally convert the orthotic to a Kirby skive with first ray cutout or the Inverted Orthotic Technique.

5 comments:

  1. Hi Dr. Blake. I hear about first met cutout constantly but fail to understand how this would be best for this person. If she has a FF varus and it appears she has a Morton's foot, long second toe then the lack of wear is because the first met (great toe) is not getting contact with the ground since it is elevated.

    The second to fourth are carrying the weight. If you lower the ground with a cut out even more under the first met (great toe) then it is even harder for her to get her great toe down.

    I understand if her great toe was plantarflexed (lower from underneath than the other 4) but clearly that isn't what is happening otherwise she would have even more wear from hitting it so hard first then rocking to the outer mets.

    First met cuts out make perfect sense if the great toe is lower than the rest but I have never understood how digging a deeper hole under the toe that carries 60% of your weight will help. Thanks.

    ReplyDelete
  2. SB, Thanks for your great insightful comment. The function of a Root Balanced orthotic for forefoot varus or forefoot valgus/plantarflexed first ray deformities is to balance the pressure and center the body weight in mid stance. From mid stance on, as this stable foot begins to resupinate, the weight shifts to the 2nd and 3rd metatarsal heads, allowing the first metatarsal freedom to plantar flex for active push off. The wear pattern seen in the metatarsal head area is produced during push off. In an ideal functioning foot, with active push off, you do not see the wear under the first met head, but on the hallux. The weight in an active push off is under the 2nd/3rd met heads first, and then the hallux, as part of the weight shift medially.
    First ray cutouts are used to unweight an overloaded first metatarsal head that can not plantar flex for active propulsion. Unfortunately, when I have heard doctors talk about them, it is more for sagittal plane blockade. Which is a conversation in itself.
    Both forefoot varus/supinatus, and forefoot valgus/plantarflexed first rays have problems with propulsion. I completely agree with your thoughts. If you think about the basic premise of getting enough weight at the time of heel lift under the second metatarsal so that the first metatarsal can plantar flex, you can image what it will take with various foot types.
    The forefoot varus foot type when balanced by the classic Root Technique has several potential drawbacks. For our discussion, the primary problem is the technique itself must put at times too much weight on the first metatarsal to balance the foot at mid stance (thus the metatarsal shaft wear pattern seen). And then what happens? As the heel lifts, the first metatarsal gets jammed upwards--preventing crucial plantar flexion for active propulsion. So, the delicate fixes for this to get the metatarsals in the same position as a normal foot are: first ray cutouts with varus positioning of the rear foot (Kirby or Inverted)---even Dr Root used to do this with extremely narrow orthotics to achieve the same end, 50% correction of forefoot varus with varus positioning of the rear foot (Kirby or Inverted), simply using the Inverted Technique since the goal is to not support the forefoot abnormality, but let the rear foot correction get the foot in the right position, reverse Morton's Extensions, Metatarsal padding especially under the 2nd and 3rd metatarsal shafts, and my beloved combinations of whatever works for that individual patient at that time.
    So, I agree with you. The first ray cutout is sold as a sagittal plane blockade help, not as a pronation help. I never understood it's purpose until I started using it in already made orthotics that were wonderful but just jamming up the first ray too much for me. They can be simple thinning of the plastic in the distal medial corner. Dr John Weed did this on 50% of his Root balanced forefoot varus of course Rohadur orthotic devices to allow for better propulsion--long before the term Sagittal Plane Blockade was coined. And now we have the met pads and the extensions that we can use for the patient's benefit.
    I hope you can see I love this stuff. In my rambling, if it is clear that I have not really answered your question, give me a rephrase. Thank YOu. Dr Rich Blake

    ReplyDelete
  3. Hi there. Thank you for this blog and for your passion!
    I have the same question SB has. Your solution sounds backwards to me, too, especially because I have recently gotten such incredible relief from supporting my first ray with an insert. I have Morton's foot, high arches and Equinus. I've had injuries of all sorts since the age of 15. Even had knee surgery (tibia tubular transfer) and almost had the forefoot neuromas removed. Finally had quit all activity in July of this year with foot, ankle, knee and pelvis pain that would not resolve. My PT had given up and sent me to a pain management doc. Two months later, the PT suggested I check out the website mortonsfoot.com. I've been using the number 6 insert since November. I am gobsmacked. Not only has most of my pain resolved, even my shoulders and neck feel better and my posture has improved. I've returned to yoga and walking and am amazed at how every way I move and support my body is different. This insert ONLY supports the first ray. I have tossed my orthodics and all arch supports. In yoga today, I jumped to the front of my mat, nearly knocking myself over (I wear Vibrams for yoga so I can wear the lift when practicing). I have so much power pushing off with my big toe. Even my calluses are thinning since my feet no longer twist at end stage pronation.

    I used to be able to get my feet flat on the floor in down dog, but my feet would be sore. When using this insert, my arches seem to "turn on" in down dog and I can no longer get my heels to the ground.

    The other thing I've noticed is that my transverse abdominals are more consistently engaged when I walk or stand.

    Anyway, curious. Have you tried to just support the first ray with a patient? If not, why?

    ReplyDelete
  4. BTW, my podiatrist is pretty good but he does not correct for Morton's foot. I plan to meet with him to let him know of my success. I want everyone to have the relief I've found.

    ReplyDelete
    Replies
    1. I am having trouble with my my 1st ray. I am having pain in my feet, knee, hip, shoulder, and neck. I also have a mild high arch. Through all of this I acquired a bunion.

      I have had a hard time getting shoes to fit. I wonder if other people find it difficult fitting into shoes.

      I did find the Mortons.com site. I do not have a mortons foot, my big toe is my longest toe, but they say on the site that it is the longer web space and the short met bone, which I have. My right foot is giving me the most problems. I lost most of my fat pad on that foot. Also obtained a bunion on my big toe joint. Very sore underneath the joint when walking.

      I was going to try them. I was wondering if they were uncomfortable at first and if it took awhile to break them in? Did you get the perfect fit or just order the 6?

      Also, how did you fit the insert into your vibrams? Curious too....

      Delete

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.