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Challenging the foundations of the clinical model of foot function

Discussion in 'Biomechanics, Sports and Foot orthoses' started by NewsBot, Jan 31, 2017.

  1. Trevor Prior

    Trevor Prior Active Member

    This would be forefoot control (medial posting) but it is applied to the cast or digital model such that it exerts the effect in the region of the talo-navicular joint.
     
  2. Trevor Prior

    Trevor Prior Active Member

    E
    Eric - how do you do it - I am imterested and cannot recall seeing it before?
     
  3. Anyone know how many devices are made using digital processes? While we talk heel bisections etc Jeff do you use any digital processes?
     
  4. Jeff Root

    Jeff Root Well-Known Member

    Mike, we use both traditional and CAD/CAM manufacturing processes. In both cases, we physically bisect the heel of the negative cast. When we digitize a negative cast we place the cast on a tray and position the heel inverted, vertical or everted and then place the tray into the laser scanner's bed and scan the cast with the heel bisection at the desired angle. If a heel is prescribed to be only a few degrees inverted or everted, we scan it vertical and then invert or evert it with the correction software. However, when the heel is highly inverted or everted as it might be with a Blake inverted device, we have found it best to scan it inverted rather than try to invert it with the correction software.

    I don't think anyone can accurately estimate how many devices are made today with digital versus traditional manufacturing techniques. In my lab about 60 to 70 percent are made digitally.
     
  5. efuller

    efuller MVP

    It may have even been in this thread. I also just wrote a piece for Podiatry Today that described how to make the decision, but didn't have room in the piece to go into how to communicate with the lab.

    I use maximum eversion height to determine the amount intrinsic forefoot valgus post that I want. Say I threw a heel bisection on a cast and that cast sitting on the table made that heel bisection sit 3 degrees inverted. The maximum eversion height for this individual was 3 mm. I would ask the lab to put a 3mm high intrinsic forefoot valgus post on the cast. Using some simple trigonometry you could figure out how many degrees this would evert the heel bisection of the cast. Say this person had a medially deviated STJ axis. I would then ask the lab to reshape the heel (medial heel skive and or plantar lateral expansion) to create a heel cup that would like an inverted heel cup. You could create a mathematical formula for this as well. Divide the heel cup in half. As you look at the heel of the cast from behind you could look at the volume under the medial and lateral sides of the bottom of the heel. If you wanted to create a more of a varus wedge effect the medial volume should be greater than the lateral volume. (This is with the anterior edge of the intrinsically posted cast sitting on a flat surface). The greater the volume difference the greater the varus wedge effect.

    The plantar lateral expansion is adding plaster to the plantar lateral side of the heel to decrease the volume under lateral half of the heel cup of the orthotic. The medial heel skive is removing plaster from the medial side of the cast to increase volume under the medial side of the heel cup.

    You can probably figure out what to do in different situations from what I wrote from above. Let me know if you have any other questions on that.

    Eric
     
  6. Jeff Root

    Jeff Root Well-Known Member

    Have there been any studies to test this method for reliability and repeatability and has it demonstrated to be more reliable than the use of heel bisections, which have been tested? And is there any evidence that it produces better outcomes? I have to assume not. Your method sounds much more inconsistent, subjective and less reproducible than using heel bisections as a means of orienting the cast in the frontal plane and modifying the cast (cast corrections) with a balance platform, medial and lateral expansions and any other modifications such as heel skives or other intrinsic cast modifications.
     
  7. xxx He's your father at last, as oppose to "Dr Root". Love.
    Not sure there have been any studies on any of this. Griff and I got a good study coming up though.......
     
  8. Jeff Root

    Jeff Root Well-Known Member

    I thought you would appreciate that! I typically refer to him as Merton Root or Dr. Root on this forum because I don't want to assume that everyone reading this necessarily knows who my father is. I have had podiatrists introduce me to students, residents and practicing podiatrists where the podiatrist making the introduction had to explain to them who Merton Root was. In fact, this has happened at every California School of Podiatric Medicine reception at the Western Foot and Ankle Association that I have attended. As a result, that is precisely why I use a more formal way of referring to my father on this forum. In addition, not everyone reading this forum is a podiatrist or has a knowledge of podiatric history so I would not expect them to know who Jeff Root's father is or what his role in podiatry was. As a result, I will continue to be more formal the majority of the time.
     
  9. Daryl:

    Thank you so much for telling me what I need to do with my time and my money. And for your information, Daryl, I have, over the past 33 years of my podiatric practice, done something other than just "complain on Podiatry Arena and Facebook". Here is an incomplete list of what I have been doing during that time:

    BOOKS

    Kirby KA: Foot and Lower Extremity Biomechanics: A Ten Year Collection of Precision Intricast Newsletters. Precision Intricast, Inc., Payson, Arizona, 1997.
    Kirby KA: Foot and Lower Extremity Biomechanics II: Precision Intricast Newsletters, 1997-2002. Precision Intricast, Inc., Payson, Arizona, 2002.
    Kirby KA: Foot and Lower Extremity Biomechanics III: Precision Intricast Newsletters, 2002-2008. Precision Intricast, Inc., Payson, AZ, 2009.
    Kirby KA: Biomecanica del Pie y la Extremidad Inferior: Colleccion de una Decada de Articulos de Precision Intricast. Precision Intricast, Inc., Payson, Arizona, 2012.
    Kirby KA: Biomecanica del Pie y la Extremidad Inferior II: Articulos de Precision Intricast, 1997-2002. Precision Intricast, Inc., Payson, Arizona, 2012.
    Kirby KA: Biomecanica del Pie y la Extremidad Inferior III: Articulos de Precision Intricast, 2002-2008. Precision Intricast, Inc., Payson, AZ, 2012.
    Kirby KA: Foot and Lower Extremity Biomechanics IV: Precision Intricast Newsletters, 2009-2013. Precision Intricast, Inc., Payson, AZ, 2014.
    Kirby KA: Biomecanica del Pie y la Extremidad Inferior IV: Articulos de Precision Intricast, 2009-2013. Precision Intricast, Inc., Payson, AZ, 2015.


    PUBLICATIONS
    Kirby KA, Valmassy RL: The runner-patient history: What to ask and why. JAPA, 73: 39-43, 1983.
    Santoro, John P., and Kevin A. Kirby: "Boot Fitting Problems in the Skier", JAPMA, 76: 572-576, 1986.
    Kirby, Kevin A.: "Methods for Determination of Positional Variations in the Subtalar Joint Axis", JAPMA, 77: 228-234, 1987.
    Kirby, Kevin A., David B. Arkin, and Wilfred Laine: "Digital Systolic Pressure Determination in the Foot", JAPMA, 77: 340-342, 1987.
    Kirby, Kevin A., Alan J. Loendorf, and Renee Gregorio: "Anterior Axial Projection of the Foot", JAPMA, 78: 159-170, 1988.
    Kirby, Kevin A.: "Rotational Equilibrium Across the Subtalar Joint Axis", JAPMA, 79: 1-14, 1989.
    Kirby, Kevin A., and Donald R. Green: "Evaluation and Nonoperative Management of Pes Valgus", pp. 295-327, in DeValentine, S.(ed), Foot and Ankle Disorders in Children. Churchill-Livingstone, New York, 1992.
    Kirby, Kevin A.: "The Medial Heel Skive Technique: Improving Pronation Control in Foot Orthoses", JAPMA, 82: 177-188, 1992.
    Ruby P, Hull ML, Kirby KA, Jenkins DW: The effect of lower-limb anatomy on knee loads during seated cycling, J Biomechanics, 25 (10): 1195-1207, 1992.
    Johnson, E. Ralph, Kevin A. Kirby, and James S. Lieberman: "Lateral Plantar Nerve Entrapment: Foot Pain in a Power Lifter", American Journal of Sports Medicine,
    20 (5):619-620, 1992.
    Kirby, Kevin A.: "Podiatric Biomechanics: An Integral Part of Evaluating and Treating the Athlete", Medicine, Exercise, Nutrition and Health, 2 (4):196-202, 1993.
    Kirby, Kevin A.: "Modifying Orthoses", Podiatry Today, Vol VII, No. 6, pp.42-46, October 1994.
    Kirby, Kevin A.: "Functional Design in Running, Court and Fitness Shoes", Podiatry Today, Vol VII, No. 9, pp. 37-44, February 1995.
    Kirby, Kevin A.: "How Much Are Orthotics Really Worth?", Podiatry Management, Vol 14, No. 6, pp. 73-77, September 1995.
    Kirby, Kevin A.: "Troubleshooting Functional Foot Orthoses", pp. 327-348, in Valmassy, R.L.(editor), Clinical Biomechanics of the Lower Extremities, Mosby-Year Book, St. Louis, 1996.
    Menz, H. B. (moderator), Kirby, K., Cornwall, M., Rome, K., Tinley, P., Murphy, N., Keenan, A.: “Clinical measurement of the lower extremity-where to from here?” Australasian J. Pod. Med., 31 (3):95-99, 1997.
    Kirby, Kevin A.: “Biomechanics and the Treatment of Flexible Flatfoot Deformity in Children”, PBG Focus, J. Podiatric Biomechanics Group, 7:10-11, June 1999.
    Kirby, Kevin A.: “Biomechanics of the Normal and Abnormal Foot”, JAPMA, 90:30-34, January 2000.
    Kirby, Kevin A.: “An Analysis of the AOFAS Paper on Plantar Fasciitis”, Podiatry Management, Vol 19, No. 4, pp. 136-137, April/May 2000.
    Kirby, Kevin A: “Conservative Treatment of Posterior Tibial Dysfunction”, Podiatry Management, Vol 19, No 7, pp. 73-82, September 2000.
    Kirby, Kevin A: “Subtalar Joint Axis Location and Rotational Equilibrium Theory of Foot Function”, Journal of the American Podiatric Medical Association, 91:465-488, October 2001.
    Kirby, Kevin A.: “What Future Direction Should Podiatric Biomechanics Take?”, Clinics in Podiatric Medicine and Surgery, 18 (4):719-723, October 2001.
    Van Gheluwe B, Kirby KA, Roosen P, Phillips RD: Reliability and accuracy of biomechanical measurements of the lower extremities. JAPMA, 92:317-326, 2002.
    Lewis GS, Kirby KA, Piazza SJ: A motion-based method for location of the subtalar joint axis assessed in cadaver specimens. Presented at 10th Anniversary Meeting of Gait and Clinical Movement Analysis Society in Portland, Oregon. April 7, 2005.
    Kirby KA, Roukis TS: Precise naming aids dorsiflexion stiffness diagnosis. Biomechanics, 12 (7): 55-62, 2005.
    Roukis TS, Kirby KA: A simple intraoperative technique to accurately align the rearfoot complex. JAPMA, 95:505-507, 2005.
    Van Gheluwe B, Kirby KA, Hagman F: Effects of simulated genu valgum and genu varum on ground reaction forces and subtalar joint function during gait. JAPMA, 95: 531-541, 2005.
    Spooner SK, Kirby KA: The subtalar joint axis locator: A preliminary report. JAPMA, 96:212-219, 2006.
    Kirby KA: Foot orthoses: therapeutic efficacy, theory and research evidence for their biomechanical effect. Foot Ankle Quarterly, 18(2):49-57, 2006.
    Kirby KA: Emerging concepts in podiatric biomechanics. Podiatry Today. 19:(12)36-48, 2006.
    Lewis GS, Kirby KA, Piazza SJ: Determination of subtalar joint axis location by restriction of talocrural joint motion. Gait and Posture. 25:63-69, 2007.
    Pascual Huerta J, Ropa Moreno JM, Kirby KA: Static response of maximally pronated and nonmaximally pronated feet to frontal plane wedging of foot orthoses. JAPMA, 99:13-19, 2009.
    Lewis GS, Cohen TL, Seisler AR, Kirby KA, Sheehan FT, Piazza SJ: In vivo tests of an improved method for functional location of the subtalar joint axis. Journal of Biomechanics, 42:146-151, 2009.
    Kirby KA: Are Root biomechanics dying? Podiatry Today, 22:(4), 2009.
    Kirby KA: Podiatry’s future: Biomechanics versus surgery or biomechanics with surgery? Podiatry Today. 22:(4):87, 2009.
    Van Gheluwe B, Kirby KA: Foot biomechanics and podiatry: Research meets the clinical world. Footwear Science, 1:79-80, 2009.
    Kirby KA: Is the grass always greener on the other side of the fence? Podiatry Today, 22(8):95, 2009.
    Pascual Huerta J, Ropa Moreno JM, Kirby KA, Garcia Carmona FJ, Orejana Garcia AM: Effect of 7-degree rearfoot varus and valgus wedging on rearfoot kinematics and kinetics during the stance phase of walking. JAPMA, 99(5):415-421, 2009.
    Kirby KA: Tales from the frontlines of daily shoe battles. Podiatry Today, 22(12):73, 2009.
    Kirby KA: Current concepts in treating medial tibial stress syndrome. Podiatry Today. 23(4):52-57, 2010.
    Kirby KA: Is barefoot running a growing trend or a passing fad? Podiatry Today. 23(4):73, 2010.
    Kirby KA: "Evolution of Foot Orthoses in Sports", in Werd MB and Knight EL (eds), Athletic Footwear and Orthoses in Sports Medicine. Springer, New York, 2010.
    Kirby KA: Why mastering biomechanics is crucial to the profession. Podiatry Today. 23(8):89, 2010.
    Van Gheluwe B, Kirby K: Research and clinical synergy in foot and lower extremity biomechanics. Footwear Science, 2:111-122, 2010.
    Spooner SK, Smith DK, Kirby KA: In-shoe pressure measurement and foot orthosis research. A giant leap forward or a step too far. JAPMA, 100:518-529, 2010.
    Kirby KA: How confusion over biomechanics can inspire the profession. Podiatry Today. 23:(12), 2010.
    Kirby KA: Introduction to Recent Advances in Orthotic Therapy. In Scherer PR (ed), Recent Advances in Orthotic Therapy: Improving Clinical Outcomes with a Pathology Specific Approach, Lower Extremity Review, USA, 2011.
    Kirby KA: Understanding the biomechanics of subtalar joint arthroereisis. Podiatry Today. 24:(4)36-45, 2011.
    Kirby KA: Have you walked a mile in your patients' shoes? Podiatry Today. 24:(4)81, 2011.
    Kirby KA: Podiatry seminar content: science or infomercials? Podiatry Today, 24:(8)82, 2011.
    Kirby KA, Barrett SL: Point-Counterpoint: Recalcitrant Plantar Fasciitis: Is Fasciotomy Ever Necessary? Podiatry Today, 24 (11):60-66, 2011.
    Kirby KA: For DPMs, it’s a wonderful life. Podiatry Today, 24:(12)82, 2011.
    Kirby KA: Will physical therapists be teaching us biomechanics in 2030? Podiatry Today, 25(4):97, 2012.
    Kirby KA: Barefoot versus shod running: Which is Best? Podiatry Today, 25(5):54-60, 2012.
    Kirby KA: Addressing perceptions of age and how they affect our interactions with patients. Podiatry Today, 25(8):97, 2012.
    Kirby KA, Spooner SK, Scherer PR, Schuberth JM: Foot orthoses. Foot & Ankle Specialist, 5(5):334-343, 2012.
    Kirby KA: Orthotics are not biomechanics. Podiatry Today, 25(12):66, 2012.
    Kirby KA: Is manual examination of the foot a dying art? Podiatry Today, 26(4):82, 2013.
    Fuller EA, Kirby KA: Subtalar joint equilibrium and tissue stress approach to biomechanical therapy of the foot and lower extremity. In Albert SF, Curran SA (eds): Biomechanics of the Lower Extremity: Theory and Practice, Volume 1. Bipedmed, LLC, Denver, 2013, pp. 205-264.
    Kirby KA: Why I Became a Podiatrist. Podiatry Today, 26(8):90, 2013.
    Kirby KA: Shoes or barefoot: Which is the best way to run? Track Coach, Fall 2013, pp. 6530-652.
    Kirby KA: Footstrike and Running Form Controversies: What Does the Scientific Evidence Tell Us? Foot and Ankle Quarterly, 24(3):109-118, 2013.
    Kirby KA: Mentoring the future researchers and educators of podiatry. Podiatry Today, 26(12):74, 2013.
    Kirby KA: Should podiatrists think more like engineers? Podiatry Today, 27(4):90, 2014.
    Kirby KA: Emerging evidence on footstrike patterns in running. Podiatry Today, 27(6):54-60, 2014.
    Kirby KA: When shoe companies make misleading health claims about their products. Podiatry Today, 27(8):98, 2014.
    Kirby KA: The evolution of foot orthoses in sports-Part 1. Pod Management, 33(9):119-123, 2014.
    Kirby KA: Is it unethical to prescribe orthoses for children with asymptomatic flatfoot deformity. Podiatry Today, 27 (12):74, 2014.
    Kirby KA: The evolution of foot orthoses in sports-Part 2. Podiatry Management, 34(2):145-156, 2015.
    Kirby KA: Prescribing orthoses: has tissue stress theory supplanted Root theory? Podiatry Today, 28(4):36-44, 2015.
    Kirby KA: What is a “normal” foot? Podiatry Today, 28(4):82, 2015.
    Kirby KA: After 30 years, has podiatry changed for the better? Podiatry Today, 28(8):82, 2015.
    Kirby KA: In defense of tissue stress theory. Podiatry Today, 28(8):14-16, 2015.
    Kirby KA: The evolution of foot orthoses in sports-Part 3. Pod Management, 34(7):119-126, 2015.
    Kirby KA: Can foot orthoses have an impact for knee osteoarthritis? Podiatry Today, 28(10):50-60 , 2015.
     
    Last edited: Mar 8, 2018
  10. efuller

    efuller MVP

    Jeff, I've looked at the reliability and repeatability of heel bisections and forefoot to rearfoot measurements. From what I have seen almost anything would be more repeatable than those measurements. At CCPM the biomechanics faculty all attempted to bisect the same heel and there was a five degree variation across the faculty in the position of the heel bisection. At a Weed seminar, I had took a volunteer and placed a heel bisection on his heel and had seminar participants measure the forefoot to rearfoot relationship. There was a 10 degree variation across the measurements. The literature that has looked at this backs my personal observations.

    Forefoot to rearfoot relationship cannot be done accurately. Within the Root paradigm there is the belief that there can be variation in this measurement over time. (supinatus) There is no protocol to assess how much supinatus there is in the measurement. The test to check a supinatus described does not provide a method for providing a number for the amount of supinatus.

    Jeff, you are on really shaky ground if you are trying to use accuracy of measurements to advocate for Root theory over some other theory. . And this doesn't even touch the problems in logic of applying the measurements to practice. (why do you balance the heel bisection to vertical when NCSP is inverted? Why do you treat the forefoot to rearfoot relationship in neutral position when the forefoot to rearfoot changes from that when the vast majority of people are in stance?)
     
  11. drhunt1

    drhunt1 Well-Known Member

    Ouch! Looks like a nerve was struck! Tell us, Kevin...how many of the articles above were peer reviewed, or are they pretty much your opinion? And what serious problems have you ever solved? (BTW...I would love to debate your article written with Santoro on ski boots sometime...it's just another area where I would run circles around you. I also noticed that you became enamored with TST in 2012...judging by your titles of your non-peer reviewed articles. What is the definition of narcissism? Why does your post above have that written all over it?
     
  12. Jeff Root

    Jeff Root Well-Known Member

    Eric, Dr. Root said that heel bisections should be accurate to within plus or minus one degree. So at CCPM the biomechanics faculty that you mentioned was plus or minus two degrees. Heel bisection can be done more accurately when examiners are trained to use the technique exactly as described by Root. At Root Lab we have trained many practitioners how to bisect the heel over the years. I can tell you that many of them were not using Root's exact method and as a result their findings were different than when they used Root's technique exactly as he described it. I know of no other orthotic lab in the country besides Root Lab that would record the ff to rf measurements on the orthotic Rx form that was sent back to the practitioner with the completed orthoses. This enabled the practitioner to determine if their heel bisection and their ff to rf measurements were within the acceptable margin of error. Our conscientious clients would work on their heel bisection and measurement techniques until they were satisfied that their results were consistent with and within a reasonable tolerance of the labs ff to rf measurements. The fact that some are not bisecting the heel or measuring the ff to rf like Root describe is the primary reason why there is so much variability in these findings. Root developed the forefoot to rearfoot measuring device. That tool is no long made and very few people have one anymore. The studies I have seen have used a tractograph to try to measure ff to rf. This instrument is not capable of measuring the ff to rf relationship accurately because of the distance between the instrument and the plantar surface of the forefoot. The lack of standardized measuring tools and techniques is the primary reason why there is so much variation in these findings.

    As for measuring a foot with a forefoot supinatus, it is measured exactly like a foot with a forefoot varus. When you measure the forefoot to rearfoot relationship as described by Root, you place the STJ in the neutral position and then fully pronate the MTJ while measuring the foot. As a result, the forefoot would be fully everted but would remain in an inverted angle to a perpendicular to the heel bisection. In other words, the measurement would capture the full degree of forefoot inversion present due to either a true ff varus or a ff supinatus.

    There is no method in existence determine how much ff supinatus there is in any foot. For example, let assume that a subject had a congenital forefoot varus of 5 degrees and over time developed 6 degrees of forefoot supinatus, giving them an 11 degree inverted ff to rf relationship. One day this patient walks into your office and you measure an 11 degree inverted ff to rf relationship. There is no way you can determine how many degrees of this patients existing inverted ff to rf relationship is due to a true (structural) ff varus or to forefoot supinatus. If you know of some method to differentiate the degree of ff supinatus from the degree of forefoot varus this would be a major advancement in biomechanics. Today it is not an uncommon practice for practitioners who suspect ff supinatus to reduce the amount of inversion in the foot during the casting process. I don't know of any method to measure how much forefoot inversion was reduce via this technique.

    As for your final point, we don't necessarily balance the heel to vertical to when the NCSP is inverted. Since I became involved with Root Lab back in the late 1970's, practitioners have balanced the heel inverted, vertical or everted for a variety of reasons. Back in the 70's some of our clients would correct the heel to an inverted position to increase "pronation control". This was long before TST ever existed.
     
  13. rdp1210

    rdp1210 Active Member

    Eric:

    Did you use a caliper as advocated by LaPointe et al in 2001 for heel bisections? I don't know why you continue to fall back on a poorly-controlled-non-published study using visual techniques only when LaPointe showed that if you use a simple piece of equipment to bisect the heel that you can get decent reliability. Let go of your personal biases on this point.

    Lack of reliability for taking any measurement is based on:
    1. Failure to fully define the technique of measurement
    2. Failure to utilize instruments that can accurately take the measurements.

    I find big problems in both respects in the literature that looks at reliability of forefoot to rearfoot measurements. First problem is that none of the literature utilizes the technique of LaPointe to bisect the calcaneus. So you're criticizing theory based on poorly defined techniques and bad instruments. Not highly scientific to be so arrogant in our assumptions that techniques and instruments cannot be improved.

    Daryl
     
  14. efuller

    efuller MVP

    I do use calipers to measure the amount of fat pad expansion that occurs with weightbearing versus non weight bearing. It is interesting to see how much this can vary. The more difference in fat pad width there is between weight bearing and non weight bearing the greater tendency there is for a line on the back of the heel to move relative to the bone. It sure would be nice if there was a way to figure out how to avoid this additional potential source of error in doing a second heel bisection. (I think I have figured this out)

    Daryl, that's just the rearfoot part of forefoot to rearfoot. You still have the supinatus problem with the line that is used to delineate the forefoot. The acknowledgement that the forefoot to rearfoot measurement changes over time is a problem. Jeff has said there is no accurate way to determine how much supinatus there is when you take a forefoot to rearfoot measurement. Daryl, yes you are right that lack of reliability can come from failure to adequately define the technique. The technique described in Normal and Abnormal vol 1 does not say what to do about the day to day variation that can occur with a supinatus. (If you disagree with the notion of day to day variation give me a study that shows that this measurement is consistent from one day to the next.)

    This discussion does lead to the question of why forefoot to rearfoot measurement has to be accurate. Root's prescription writing protocol looks at the heel bisection and lets the forefoot "correction" happen based on where you put the heel bisection. The protocol does not need an accurate forefoot to rearfoot relationship. If you choose to balance the heel bisection to vertical when the NCSP is inverted, you are not creating a device that has the forefoot to rearfoot relationship of the foot when the heel bisection is vertical. That is if you measured the forefoot to rearfoot relationship in the position that it is standing in, it would be different than what was measured when the STJ was in neutral position. So the protocol is already "ignoring" the actual forefoot to rearfoot relationship in stance. Daryl, I appreciate your study that showed that forefoot to rearfoot changes as the STJ moves. So, if the goal is to pronate both axes of the midtarsal joint to their end of range of motion the prescription writing protocol, as written, won't do that. If you had the patient stand and attempt to evert their foot you could see how much intrinsic forefoot valgus post would pronate the LMTJ to its end of range of motion. (Maximum eversion height test) (I also glossed over a large number of other problems with the logic of the protocol, but wanted start with the main point that it is not internally consistent even when you ignore the other problems.)



    Daryl I've been thinking about how to answer your LMTJ question. I believe the question was can the LMTJ be stable with ..... Anyway the question can be answered by looking at the motion that does occur at the TN and CC joints with LMTJ axis motion. If you push the cuboid upward relative to the calcaneus, does this cause a downward motion of the navicular relative to the talus? Usually not, but you can make that downward motion of the navicular happen if you push it down and that would give you motion about the LMTJ axis. However, if at the same time you push the cuboid upward and you pushed the navicular upward, at some point the plantar ligaments of both joints would become tight and you would reach a stable position. There is still potential for abduction adduction of the joint(s), but that could be held stable by co contraction of the peroneus brevis and posterior tibial muscles.
     
  15. rdp1210

    rdp1210 Active Member

    Just a couple of quick thoughts:
    I agree that the skin lines move during WB and even when the STJ moves. But that is correctable (just like telescopes can now correct for atmospheric conditions).

    Yes, the EROM of the MTJ is a soft tissue constraint mechanism. Therefore the ROM of any joint that has soft tissue constraint will change from day to day, including STJ and MTJ and ankle joint and MTPJ. That doesn't mean we shouldn't be measuring it. Maybe an average over several measurement days would be more accurate -- similar to the way that BP varies from minute to minute -- though we look at the average, we still document the moment-to-moment numbers. As I have pondered Root's technique for determining the EROM of the MTJ, what I realize is that the MTJ pronation EROM is that point at which additional dorsiflexion of the 4th-5th metatarsal heads starts producing a pronation movement around the STJA. Notice that Kirby pronates the MTJ to its EROM before he starts feeling for STJ movement in the palpation technique for STJA determination. Why do you get MTJ motion first instead of STJ motion, when you dorsiflex the lateral column? Because of the big difference in the radius of gyration of the foot around the STJA vs. the LAMTJ.

    Thanks for a thoughtful reply,
    Daryl
     
  16. efuller

    efuller MVP

    What did you think about my point that you don't even need an accurate forefoot to rearfoot measurement within Roots prescription writing protocol?

    I agree the joint that moves most is the one with the largest moment :moment of inertia ratio. For forces that cause rotations there are force couples. If you apply a force to a metatarsal head at first you will get linear motion of that metatarsal head. When you start seeing rotation there hast be a counter force at the base of the meatarsal. If there is a counter force at the base of the metatarsal there will be an equal and opposite reaction force from the base of the metarsal on the cuneiform,,, and so on all the way up to the inferior surface of the tibia. The applied force will create a moment at all joints that it has leverage for. This is why you don't have to fully load the MTJ when doing the STJ axis palpation test. If you look at a sagittal view of a foot. Then have someone push upward on the first metatarsal head, you will see ankle dorsiflexion before the first ray reaches its end of range of motion.
     
  17. Jeff Root

    Jeff Root Well-Known Member

    Eric, I did not know that there was any evidence that can be day to day variation in the amount of forefoot supinatus in a foot. How can there be day to day variation when you don't believe that heel bisections and ff to rf measurements are accurate in the first place? In addition, I don't believe there is any objective way to determine if forefoot supinatus is present in any foot. I know that Root and perhaps others described techniques to try to clinically identify forefoot supinatus but I don't believe there is any objective way to do this nor do I believe there is any objective way to distinguish the degree of forefoot supinatus versus the degree of forefoot varus present in any given foot. Do you?

    My understanding of the definition of forefoot supinatus is that it is an acquired element of forefoot inversion relative to the rearfoot. What is interesting to me is I don't know how you or anyone can talk about forefoot varus or forefoot supinatus unless you have some point of reference in the rearfoot to establish the presence of an inverted forefoot condition in the first place. If heel bisections are unreliable and if there is no other reference that enables us to measure the forefoot to rearfoot relationship in a foot, then those individuals who don't believe heel bisections are unreliable should certainly not be discussing any inverted or everted forefoot condition in the first place. You can't use the plane of the floor as a reference to determine the presence of forefoot varus or valgus, you can only use the plane of the floor to describe the angle of the plane of the forefoot to the floor at any given moment in time. For example, if we have what I would call a perpendicular ff to rf relationship and you supinate the foot in space, the forefoot would now be inverted to the floor. That doesn't mean that the foot has a forefoot varus, it just means that the plane of the ff is now inverted in relationship to the floor. So how can you talk about forefoot varus and forefoot supinatus unless you accept some point of reference in the rearfoot such as a heel bisection? Doing so seems like a total contradiction to me.
     
  18. Jeff a FF Supinatus is a soft tissue related change. Because if the elastic nature of soft tissue it will always be changing depending on the loading of that day.
     
  19. Jeff Root

    Jeff Root Well-Known Member

    First off Mile, in order to prove that forefoot supinatus can change from day to day you would have to be able to reliably measure the degree of forefoot inversion relative to some consistent reference on the foot and with the foot in a consistent position of measurement, especially at the STJ and the MTJ. So I'm playing the devil's advocate here because Eric says on the one hand that forefoot to rearfoot measurements are unreliable and then says that the degree of forefoot supinatus can change from day to day. So how does Eric know that the ff supinatus can change from day to day if ff to rf can't be reliably measured? I have never seen anything in the literature to suggest that ff supinatus has been documented to change from day to day, have you?

    I have written many times on the PA and the Podiatry mailbase about how the degree of acquired forefoot conditions can change over time with foot orthotic therapy. I have seen inverted and everted ff conditions decrease over time (typically within a few months) as a result of orthotic intervention. I have also seen these condtions increase over time in spite of orthotic therapy (this assumes that the patient was being honest about compliance). However, I have never heard anyone nor have I seen anything in the literature to suggest that there is any measurable change from day to day.
     
  20. Jeff Root

    Jeff Root Well-Known Member

    Eric,
    Root's treatment and orthotic manufacturing protocol, in most but not all cases, was to use a neutral position cast with the MTJ fully pronated to make the orthosis. He did advocate taking a cast pronated at the STJ with the MTJ fully pronated some instances, but that was reserved for select circumstances and conditions. Root found that in most but not all cases, a cast taken in the neutral position at the STJ and with the MTJ fully pronated created very efficacious orthoses even when the heel of the cast was corrected to vertical and not to the inverted neutral position. This standard was developed in the days of Rohadur orthoses and in the days when a 16 mm heel cup was considered high. As time when on, and as labs became much better at molding plastics, and as other plastics such a polypropylene became popular, labs were able to create much deeper (higher) heel cups. As a result of the use of deeper heel cups, practitioners began to correct the heel inverted with greater frequency. This was a natural evolution of Root's original protocol and as I have mentioned many times before, Root himself began to advocate correcting the heel of the cast inverted with increased frequency. This would have been in the early 1980's.

    As I have also mentioned many times, John Weed developed the orthotic valgus onlay to increase the angle of valgus support in the forefoot to address the increased forefoot eversion that occurs when the heel of a patient with a rearfoot varus and a forefoot valgus assumes a pronated position at the STJ when wearing an orthosis.
     
  21. rdp1210

    rdp1210 Active Member

    Not sure what type of linear motion of a metatarsal you've ever seen or measured.

    I'll be happy to sit down with you and go through the actual calculations. It sounds good to you in your mind, however please put some pencil to paper and calculate the actual moments, making sure to put the moment of inertias into the equation around the axis for the MTJ and the STJ. (T = I*angularacceleration) You will find that when you multiply that radius of gyration squared factor into the equation that the moment of inertia of the forefoot around the MTJ frontal plane axis is far-far less than the moment of inertia of the foot around the STJ axis. Thus your actual movement around the STJ is negligible until you reach a significant amount of tension in the ligaments crossing the MTJ. No one knows what that tension point is -- neither you nor I nor anyone else reading this. Dr. Hillstrom did start an experiment at one time to measure it.

    I throw this out to the entire PA -- If there is a research project that is most desperately needed, it is this one, to measure the forefoot to rearfoot relationship with various torques on the forefoot. We have to come up with a better definition of where the EROM of the MTJ really is. (Likewise we need to have a MUCH better definition of what constitutes a short Achilles tendon).

    Daryl
     
  22. Wouldn't it be better looking at the amount of force required to dorsiflex the ankle x degrees past 90. If we don't look at force then there is no such thing as a short Achilles you just didn't apply enough force.

    My guess would be involving a formula that takes into account the patients weight.
     
  23. Doesn't need to be measured by degrees. For us to say it so. I think we all agree to the how's and why of a FF Supinatus the more a pt stands the more force. Being a soft tissue issue there will be a spring back affect during rest ie sleep. Might be nice to know or prove it but I think most would agree that what Eric described does happen
     
  24. efuller

    efuller MVP

    Jeff, my point is that forefoot to rearfoot is not a reliable measurement. The people who developed the measurement noted that it could change over time. This one reason that the measurement is unreliable. If someone wanted to believe that it was reliable, and that they admitted that it changed over time, they would have to know how fast it changed. To prove my point I can stop here, the measurement does change. For someone to show that forefoot to rearfoot was reliable they would have to show that it does not change from day to day.
     
  25. Actually, we have two types of reliability that we can discuss here: within-day error and between-day error, the latter is larger in all clinical measures. What we cannot discern is any "real change" from the measurement error. So, when someone talks of "diurnal variation" we have no way of distinguishing this from repeated measurement error. But what about if i do 10 measurements one after the other- surely the body can't change that quickly, that's all got to be down to measurement error, right? Prove it....
     
  26. efuller

    efuller MVP


    Jeff, I agree that the Root protocol works a lot of the time. However, you did not address my point that the forefoot to rearfoot relationship in the cast is not the forefoot to rearfoot relationship that would be measured with the STJ in the position that it is standing in. It's not just that the cast is not balanced to neutral, it's the casted STJ position (and hence forefoot to rearfoot relationship) are not the same as the stance STJ position. Therefore the orthotic is not treating the forefoot to rearfoot relationship that exists in the foot when it is standing. This is why I am questioning whether or not getting an accurate forefoot to rearfoot relationship even matters. I think there are more logical ways to decide if you want to add an intrinsic forefoot valgus post. (Maximum eversion height) The Root protocol works a lot of the time in spite of a lack of internal consistency in the logic of why it works.
     
  27. Of course an accurate measure of angular relationship doesn't matter. As long as an orthosis is basically providing reaction force in roughly the right place, in roughly the right direction, at roughly the right time then that's as good as we can ascertain. "Bringing the ground up to the foot and negating the need for compensation" is a callow view of how foot orthoses exert their therapeutic effects.
     
  28. efuller

    efuller MVP

    So, what would we do with a better forefoot to rearfoot measurement? The treatment protocol with orthotics does not require the measurement to be exact. The forefoot to rearfoot measurement in neutral position is different than the forefoot to rearfoot relationship of the foot in stance (except for the exceedingly rare occurrence of the foot standing in neutral position of the STJ).
     
  29. mazzopod

    mazzopod Member

    For how long during the gait cycle does the foot remain in it's "neutral position"? In some cases it never gets there so why try and maintain the angular relationship between forefoot and hindfoot found in the NCSP ? Surely it's more important to reduce the stresses on the tissues that are subjected to eccessive overloading that may or not be due to hindfoot vs forefoot alignment......! Not all feet that are pronated or supinated are symptomatic therfore establishing with absolute accuracy the degrees of forefoot varus/supinatus or hindfoot varus or valgus becomes unnecessary because the degrees of correction applied to our orthoses doesn't align the calcaneus or forefoot as per the degree of correction applied. What the correction does is to reduce the moments around the STJ and MTJ axis and therefore reducing soft tissue stress and not necessarily osseus alignment.
     
  30. Jeff Root

    Jeff Root Well-Known Member

    Eric,
    I did address this when I told you how John Weed used a valgus onlay to increase the degree of forefoot valgus support in the orthosis on some of his patients who were not "controlled" to his satisfaction because the foot functioned in a pronated position at the STJ, thereby preventing the orthosis from fully pronating the MTJ due to the increased range of MTJ eversion ROM. Root recognized that the amount of ff inversion decreased and that the amount of forefoot eversion increased when the STJ was pronated as compared to when the STJ was in a neutral or a supinated position. There are a number of ways this issue could be addressed today, if desired. One could cast the foot in the degree of STJ pronation that occurs when the heel is vertical while fully pronating the MTJ to its fully everted position. Or one could cast the foot in neutral and correct the heel to the inverted degree of rearfoot varus and then design the orthosis so that it would attempt to support the foot in the inverted neutral position, thereby eliminating the need for additional valgus support in the forefoot.

    When you use the maximum eversion height to determine how much valgus wedge to use in the forefoot, you are using a weight bearing technique. However, if you take a non-weight bearing cast of the foot, the joints of the foot will not be in the same position as in your non-weight bearing cast. So how is this any different than the fact that the joints of the foot may not necessarily assume the same position in stance as they did in Root's neutral position casting technique? The issue, as I believe Simon correctly pointed out, is that as long as an orthosis is basically providing reaction force in roughly the right place, in roughly the right direction, at roughly the right time then that's as good as we can hope for. So in some cases, a Root type functional orthosis may not be supporting the forefoot in its full degree of eversion relative to the rearfoot. But that doesn't necessarily mean that the device isn't "providing reaction force in roughly the right place, in roughly the right direction, at roughly the right time".
     
  31. Jeff Root

    Jeff Root Well-Known Member

    The goal of Root Functional orthotic therapy is not to support the foot in the neutral position. It is to use, in most but not all cases, a neutral position cast to make an orthosis that enables or promotes necessary motion and resists pathological motion/forces or "abnormal" motion.
     
  32. OTC devices work
    Foot scanning for devices work

    The % of devices made using neutral position casting in the World is tiny.

    You don't need that in your definition
     
  33. Jeff Root

    Jeff Root Well-Known Member

    Mike,
    1. What definition of forefoot varus and forefoot supinatus do you subscribe to? Clearly we can't have meaningful conversation if we don't have common, adequate and consistent definitions and vocabulary. Please give me your best definitions for forefoot varus and forefoot supinatus and ideally you reference for these definitions.
    2. How many foot orthoses should we considered as "tiny"? If you are trying to dismiss the significance of the number of foot orthoses made from neutral position casts in the world I think you are sadly mistaken.
    3. If you think that the vocal minority of those who participate on the podiatry area represent the entire biomechanics community then I again think you are mistaken.
     
  34. No Jeff I work in a country that 99% of people who prescribe custom make insoles have not even heard of Root et al and my employer makes over 20 000 custom insoles a year not 1 using Root neutral.

    Of all the people claiming to use Root neutral my guess is over 50% are not using the technique correctly.

    So when you start looking not many people are using true Root neutral and they get better. Their devices "work "

    I like the idea of using cardinal body planes as the reference starting point. Trevor made the point about the ground. Makes sense as this is what we are standing on and GRF is what orthotics have the ability to change

    No Jeff I don't consider PA the total or a representative of people making devices Just like I don't think Podiatry is the only group of people making devices to treat people.

    I have worked in 4 different countries and taught Podiatric Biomechanics so I think I can have an opinion on who uses Root and not . It maybe used in the US but how many are even doing it by the letter of Law?

    As for my definition of the Supinatus let me come back to you but it will be something around cardinal body planes with the plantar surface heel to FF . Ankle at 90 degrees. Do it need to be measured hope. What is important is Stiffness and what compensation takes place when and where. Eric maximal Evererson testing but again I don't measure mm.

    Got to go now
     
  35. mr t

    mr t Member

    Hi Everyone,

    Thank you for the discussion.

    Jeff, I wholeheartedly understand and agree with your position as I am a fellow laboratory owner. The overview of your point seems to be that you believe that a reference point is critical in achieving good prescription -> CAD accuracy and reliability, and also that the most appropriate method for achieving this is by using a widely understood reference point – the heel bisection. How this reference relates to the function of the foot seems irrelevant, it is simply fundamental to have a reference point when manufacturing an orthosis. It also seems that you are willing to embrace any method that will improve your product – this is only logical unless you have purchased a system that will only capture a foot scan using a particular methodology.

    There seems to be a more semantic argument that ‘measurements don’t matter and it’s all about how forces are applied to the orthotic surface’. However, prescription variables utilised by all laboratories worldwide (and individual Podiatrists doing their own modelling) are largely focused on applying millimetres, percentage or degree changes to shape that has initially been generated based on a patient’s foot. This captured shape must be well understood and measured or the prescription changes applied to the orthotic surface will be non-quantifiable.

    A CAD system that does not use a referenced and measured foot as a starting point for the application of surface changes appears to be highly subjective. If this change is based upon a weight-bearing scan then a reference point for the frontal plane appears irrelevant, however, the degree to which changes must then be applied seems poorly understood and highly subjective among virtually all clinicians that I have encountered. If we capture a weight-bearing scan and a non-weight bearing scan, how well do Podiatrists understand the differences to the orthosis shape that need to be applied to achieve the identical clinical outcome? It seems that there is an ideal magnitude of force that should be applied to certain regions of an orthosis. I would like to think that there is one optimal orthosis shape for a patient at the time of dispense (granted that this may change over time).

    I have no affiliation with any particular methodology. I distribute open-loop scanners and will never sell locked equipment as I believe it is in the best interest of the profession for Podiatrists to choose technology that best complies with evidence-based practice. However, I think if the same individual was sending me a 3D scan from a weight-bearing and a non-weight bearing they would have a very poor understanding of the changes required achieve this optimal shape.

    A non-weight bearing 3D scan that has (a) frontal plane reference (b) sagittal plane translation reference if poor heel capture (c) 3D scaling information if using a less than ideal 3D scanner, appears to be more logical as an initial starting point. A non-weight bearing scan at least provides a maximum Z elevation across certain regions that may not tolerate any increase. A weight-bearing scan appears to be more - 'to what limit?' If anyone on here can provide a clarification as to how they apply surface changes to an orthotic shape based upon a weight-bearing scan shape then that would be of great interest. It may even assist me in educating my customers that wish to use this methodology.

    Just clarifying again – I don’t care what methodology people use when sending work to my lab. I have no bias stemming from financial investment. It just baffles me when people say that measurements don’t matter in a manufacturing sense. It’s a statement that appears to show either a lack of understanding or illuminates an ulterior financially motivated interest.

    I have attached a sample 3D scan captured and aligned according to (a) a heel bisection which provides a resultant forefoot supinatus of 10 degrees and (b) ignored the heel bisection and have simply aligned the scan at zero degrees/flat.

    As you can see in the images there is a peak MLA height change of 10mm, not to mention changes across the entire surface (keeping in mind that the orthosis generated is a direct negative of this shape as a starting point).

    It seems very illogical and irresponsible to not consider a reference alignment as without initial measurement you can’t quantify change.

    Yes, your honour. I can tell you what I didn’t do...”
     

    Attached Files:

  36. Petcu Daniel

    Petcu Daniel Active Member

    How it can be known if certain regions could or could not tolerate an increase of elevation compared to the maximum elevation provided by non-weight bearing scan/cast surface? How do we know the non-weight bearing surface is the limit for those areas? Knowing this answer could lead to the answer for the weight-bearing cast/scan shape. One example could come from prosthetic field where the socket's positive cast is modified through material addition or removal from specific areas. A good example from trans-tibial prosthesis (figure 18B 23-26): http://www.oandplibrary.org/alp/chap18-02.asp
    Daniel
     
  37. Jeff Root

    Jeff Root Well-Known Member

    Mike, I am looking forward to your answer as to the definition of ff varus and supinatus. I don't know how you could use the plantar, rounded surface of the heel as a reference to determine the angle or plane for the forefoot. Root defined the plantar surface of the heel as a line that is perpendicular to the posterior bisection of the heel. Although you could put two points on the heel as a reference, or three points on the heel to describe a plane, I don't think that these points would have any real anatomical significance. Heel bisections, even though there is some degree of variability, do have anatomical significance. I remain perplexed as to how anyone could use the terms ff varus and ff supinatus unless they, and ideally everyone, has an agreed upon and logical point of reference.
     
  38. rdp1210

    rdp1210 Active Member

    Mike,

    The largest manufacturer of "custom made" foot devices in the U.S. is Foot Levelor in Davenport, Iowa. They have been a big supporter of Palmer Chiropractic for decades. They certainly don't use neutral position casting, and their devices work on some people. Of course there is a lot of people they don't work on. Likewise the Whitman plate worked for many years on a great many people -- met a few of them myself and they didn't use Root's neutral system. You can put a box of tissue paper in the shoe and it will also change function of the foot in some people to the point that they will be totally asymptomatic.

    I really think that you need to go back and read Root's first publication in 1964, "An Approach to Foot Orthopedics" Feb 1964 (interestingly 1 month before Wright, Desai and Hendersons paper). I think that you will find Root arguing more for a scientific approach -- not necessarily his own ideas. Unfortunately I find on this mailbase much to do about a personality, not about one idea or another. The message I got from Root was that it was time to bring science into the clinic. That meant a much greater quantification of what we observe. Unfortunately, the post-Root people have been disappointed with most of the measurement reliability studies that have been published (there have been a few that do show good reliability), so in their haste to discredit a personality and not really analyze the flaws of their own studies, they have advocated getting away from taking any measurements. And of course this advocacy has been picked up by the bill-payers and so those who are trying to take measurements and being clinically scientific are being told they can't get paid for such. Unfortunately, a science cannot progress without numbers. And you can't have numbers unless you have a common point of reference from which to count. Imagine two people trying to get to the same place at the same time without there being a Greenwich meridian. An arbitrary line to be sure -- yet a reference line that allows life to function in a much more orderly manner and get a lot more done. Certainly many cultures have survived with no knowledge of that line and there are those who want to go back to such conditions.

    As noted above, a great many things can be put in the shoe and many of them will alleviate symptoms. But is that really science? Is that the best we can do? I had the chance several years ago to visit the office of Dr. Howard Dananberg. He may not have been practicing with the exact same thought process that I was using, however I came away totally impressed with how much effort he was putting into documenting before and after function with video and pedobarograph data. I haven't met anyone since who put that much effort into collecting data on their patients before and after treatment. I count him as one of the truly great scientific clinicians. At the most recent Schuster seminar I met a person who had visited Dr. Root's office in his young days, and found that Root had kept meticulous records in a big book, of the measurements on all his patients. No one seems to know what happened to that book, but it would be invaluable today. Those who decry measurement systems are doing the profession and the public a disservice. With many of the comments on this arena, I can only say that I'm glad that some aren't astronomers, for they would probably want to get rid of telescopes and go back to reading the constellations with the naked eye. (not that there weren't a great many ancient sailors who sailed without a telescope or any other instrument and got to their destination just fine. Maybe next time you take a cruise, you could book with one of those sailors who don't need any measuring systems. I'm sure you'd have fun on that cruise as well and the food would be good too.)

    So now it's time for the anti-Root measurement people to actually post a list of the measurements that are needed to evaluate a patient for whom some type of shoe orthosis is needed. Let's look at the clinical science of those who say that Root's measurements are not a good idea. Let's start with Dr. Kirby and Dr. Spooner posting their recommended biomechanical exam form that should be done. I will be happy to post mine as well. As I noted above -- no measurements, no science.

    Daryl
     
  39. mazzopod

    mazzopod Member

    I agree that measurements need to be taken but we also need to “filter” these measurements acquired because if most of these measurements are relatively inaccurate due to human error then correcting a hindfoot or forefoot pathology with 5° more or less during orthotic balancing is certainly going to make a difference to the end result.
    What do I do if a patient presents with a peroneal tendinopathy and a hindfoot varus pathology? Do I treat the hindfoot varus or do I treat the overloading of the peroneal tendons with a lateral heel skive to reduce the internal and external supinatory movents around the STJ and AJ ? I think in this case reducing the stress on the peroneal tendons prevails........ How will my clinical measurements alter my orthotic prescription and what is a laboratory going to do with these measurements?
    I honestly think that good sense and experience needs to be applied in every case and there can’t be hard and fast rules that dictate orthotic prescription.
     
  40. rdp1210

    rdp1210 Active Member

    First I'm going to fully agree with your last statement -- and I also know that Mert Root fully agreed with your last statement. You're treating patients, not foot numbers. The same can be said of any clinical aspect. Physicians don't treat diabetes, they treat patients who have diabetes. (Leonard Levy used to say variations of this theme over and over.)

    Next you have to work on is your own intratester reliability. I have a paper that needs to be polished off that shows my own intratester reliability over a 25 year period of time. If you are not getting good intratester reliability then you need to find out why. Is it my technique or my instruments that need refining? McPoil admitted in one of his papers that a previous paper only showed good intertester reliability after the testers had worked very hard on developing such, and that physical therapists really don't have time to work on getting that good reliability. That was a sad admission.

    As to you question on what to do about the peroneal tendinitis with hindfoot varus pathology. It is important that we remember basic tendon mechanics. Can you get a tendinitis if the tendon is not being stretched beyond its resting length? By hindfoot pathology, I take it that the patient has a rearfoot varus deformity, not that the patient is standing with the rearfoot in a supinated-inverted condition. Even if the patient has a partially compensated rearfoot varus -- i.e. one in which the heel is inverted from perpendicular though the subtalar joint has used it full reserve of pronation. If this is the case, then the only reason that you would be getting peroneal tendinitis would be that the midtarsal joint is highly supinating. So once again, you have a patient presenting with peroneal tendinitis and you're trying to figure out first why the tendon is being stretched beyond its resting length. Numbers can help you find this out. (I always found it interesting that Bill Orien used to talk about the peroneus brevis being an important supinator of the foot. I'll leave that discussion to another time.)

    Finally the lab doesn't do anything with those measurements. You do something with them. The lab only does what you tell it to do. It's time for physicians to design their own orthotics instead of depending on labs to do their work. Mert Root used to talk about this, you take your measurements and then decide how many degrees of posting you want. You mark your own casts. You take responsibility for deciding if the subtalar joint needs more pronation, or if the midtarsal joint needs more pronation, of if the first metatarsal needs to be pushed down a little more. I had a nice talk with one of my classmates recently who has started teaching podiatry students how to make their own orthotics. If anyone really wants to learn biomechanics, make your own orthotics for your own patients. You'll find out a lot real fast. Only when you're good at it yourself, do you then allow the orthotic lab to do it for you, but don't let go of the control. If a lab tries to tell me what I want, I fire that lab.

    Take care,
    Daryl
     
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