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Midtarsal joint locking

Discussion in 'Biomechanics, Sports and Foot orthoses' started by mike weber, Nov 19, 2009.

  1. Members do not see these Ads. Sign Up.
    Ok before people start yelling and screaming I´m not talking about Midtarsal joint ( MTJ) to Subtalar joint ( STJ).

    I´m thinking about Cuboid - Navicular . So in other threads and in Nester et al ( see paper below) It has been discussed that the limited range of motion of the this joint about 5 degrees is not something that should be or concern. Nester et al go on to describe the MTJ and how it works around a single functional MTJ axis ( again see paper)

    Greater minds than mine have also expressed that movement in this joint is not so important to consider clinically.
    For those who want to know how much the joint moves for 4 people in a bone study see the paper below.

    The graph below is from Arndt etal article and is of the movement of the Cuboid-Navicular joint .

    What I’ve noticed in my reading is that at about the 60 % of stance phase movement within this joint reduces. I.e. as heel lift begins.

    So then I thought about what is happening at this time, Windlass and among other muscles Peroneus Longus (PL) contraction.
    This brought to mind compression and shearing stress being increased at the cuboid-navicular joint.
    So I went off to read Kevin newsletter on DMICS( see link below).

    But that did not answer my questions.

    So what are my questions.

    They revolve around Osteoarthritis ( OA) of the midfoot especially the cuboid- navicular joint and why the occur more often in a classic flexiable pes cavoid foot type or lateral deviated STJ axis, forefoot valgus, plantarflexed is 1st ray foot type.

    My conclusion increased compression force in this foot type due to over active PL, normally less force required for active windlass (very effective windlass if I´m allowed to say that). This leads to increased compression forces of the cuboid-navicular joint, then as the talus changes position is will apply pressure to the navicular which will then lead to an increase in shearing stress.

    What do people think ?

  2. Right so how there lots of reading.

    And the Bojsen-Moller article goes into compression force with the calc-cuboid joint, Which then will play a roll in the compression and shearing forces of the cuboid-navicular joint.

    This will I beleive lead to a higher amount of midtarsal OA.

    How do me identify these feet and how do we treat ?

    I would assume most will mention control of STJ axis and calc and talus, but what could be done with the midtarsal joint +

    So stuff to consider


    ps nice to have a data copy of Bojsen-moller. Just had a photocopy thanks Simon
  3. efuller

    efuller MVP

    The biggest forces happening at 60% of stance phase are Achilles tendon tension and ground reaction force on the forefoot. These forces will cause a plantar flexion moment of the rearfoot and a dorsiflexion moment on the forefoot. At that point in time, till the end of gait the bones will be pushed in dorsiflexion quite strongly.

    The cuboid navicular joint is a fibrous union. How do you diagnose OA of that joint? There is no normal joint space. How often do you see navicular cuboid arthrits?

    The windlass forces are predominately in the sagital plane. They don't really compress the navicular into the cuboid. Peroneus longus tension won't really compress the navicular into the cuboid as there would tend to be a shear at either the met cuneiform or cuneiform navicular joint. The pull from the P longus tendon will be directly resisted across the cuneiforms and then to the cuboid. It won't compress the navicular into the cuboid.

    Also posterior tibial tenon tension will tend to pull the navicular away from the cuboid. That tend to make the forces between the navicular and cuboid tension rather compression. The fact that there is not any articular surface there also supports this direction of force concept.

    Further thoughts are available in the thread cited by Simon.


  4. It seems I´ve gone on the wrong stream with my thoughts and my reading then. I thought it would be intersting discussion about shearing and compression stress but I guess not. Off to read some more. Thanks for your reply´s simon and eric
  5. Admin2

    Admin2 Administrator Staff Member

  6. Sorry just can´t seem to get this out of my head...

    Eric you said this

    But in most of the info I´ve read people have discussed that about 5 degree is not significant, but would this not mean tension forces between the cuboid and navicular be significant.

    Also I can see the bones moving away from each other in Pronation but in Supination would there not be reduced ROM therefore increase bone to bone tension between the Cuboid-Navicular ?

    I have read the thread that Simon put up 2 -3 times but no where is there a mention on forces between navicular-cuboid.

    If we consider the bones move as one unit there in my head there must be compression forces. If they move independtly there will be tension , compression and shearing forces. This must have some clinical significance ?

    Or is the reality that we should be discussing the calcaneal-cuboid as a unit and talo-navicular as the other major unit in rear and mid foot joints and mechanics?

    sorry if I´m going over old ground and I´m the only person who doesn´t get it
  7. Michael:

    I am not really quite sure what you are asking here, but let me try to help with some of the basics.

    We know that there is limited range of motion between the navicular and cuboid, probably on the order of less than 5 degrees from all the cadaver studies and live subject bone pin studies. In order to have this little available range of motion, a mechanical analysis would tell us that there needs to be both compression and tension forces between the navicular and cuboid to limit the motion at the joint this much. In other words, the restriction of motion between the navicular and cuboid needs to come from forces acting on these bones and the most likely forces that prevent more than 5 degrees of motion are: 1) strong ligaments joining these two bones causing tensile forces on both the navicular and cuboid, and 2) the close interposition of these two bones to each other which causes compression forces between the bones.

    About nine years ago, when Chris Nester and I were discussing midtarsal joint function over some beers at my home when he was visiting Sacramento for a conference, we talked quite a bit about navicular and cuboid modelling. We had discussed his idea that if we were to model the navicular and cuboid as one rigid segment, then we could model the midtarsal joint as having only one axis of motion, which would greatly simplify the explanation of the moving axis of the midtarsal joint in space. We also discussed the concept of three reference axes for the midtarsal joint which we both felt was the way to go in discussing MTJ function, which Chris subsequently published a paper on.

    The work that Chris and his coworkers have done on this subject is simply ground-breaking and I am so happy that he has taken up this subject to research further since we have learned so much already from what he and his coworkers have done. I would suggest you read all of Dr. Nester's papers, and my newsletters on MTJ research in my books, to give you a better handle on this very important subject.
  8. Hi KEVIN,
    I was trying to create a discussion about compression force but it appears that Eric believes that there will be little or no compression force during the the last 60% of the stance phase . He even went on to say that the 2 bones would move appart.

    Ive read Chris´s papers and alot of your MTJ information and the thread from 2006 on MTJ I understand the information about the single axis it very easy to understand.Ive taught students this....

    So my reasoning was 2 bones moving together = compression force. Therefore a force which I have not seen discussed anywhere in relation to the cuboid-navicular, I thought that might be intersting to discuss when and where that force might be increased or decreased.

    But then Eric talks about the cuboid-navicular moving away from each other in the last 60% of the stance phase ie tension stress.

    So now I can see 3 different views on the midtarsal joint.

    1 single axis moves as 1
    2 2 seperate bones with different movement independent from each other
    3 a bit of both. ie when compressed 1 axis combined movement when appart independent movement.

    Ive also had discussion with one of the Guys doing the bone pin studies on more than once. We keep comming back to the same point about independent movement being important with these 2 bones.

    So if the 3rd option is the case that might be a great discussion about when the bone come together or are seperate and when during the gait cycle.

    Or maybe I´m just making this too hard and should think about ROM and Quaility of ROM
  9. Michael:

    For me, there is no question that there are significant compression forces acting between the navicular and cuboid bones during weightbearing activities that help to stabilize the two bones against each other.

    There is also no question that there is movement between the navicular and cuboid during gait. The research has shown this to be so. The question thus becomes whether the movement between the navicular and cuboid is significant enough to consider these movements biomechanically or clinically important. Most researchers and biomechanists would say that the movement between the navicular and cuboid is so small, that for most purposes, the cuboid and navicular can be effectively modelled as one rigid segment with little inaccuracy.

    You must remember that modelling is not reality, but rather is an attempt to represent reality by simplifying the system in question.

    Hope this all makes sense.
  10. efuller

    efuller MVP

    Why would there be reduced range of motion available with STJ supination? We are talking about relative motion between the navicular and cuboid. This is different than what we generally consider as midtarsal joint motion. Midtarsal joint motion is motion of the cuboid and navicular relative to the talus and calcaneus.

    Just because the bones move as a unit does not necessarily meant there are compression forces between the two bones. Take two bones attached by a ligament and pull one away from the other. The bones will move as unit because of tension in the ligament.


  11. Eric:

    In the laboratory, in the conditions created on a materials testing machine, for example, certainly the conditions could be created for just tensile forces and no compression forces between navicular and cuboid. However, in the intact foot, regarding rotational motion, not translational motion, which we are talking about here, the ability of the navicular to resist rotation relative to the cuboid is unlikely to occur without the existence of significant compression forces between the navicular and cuboid (or interposed ligaments) in the human foot during weightbearing activities. I believe free body diagram analysis will show this quite nicely.

    Just because there are no anatomically discernible articular facets between two bones does not mean these two bones don't exert compression forces on one another. (I'll need to check my Sarrafian textbook later to see what the master of foot anatomy says about these two bones and any articular facets between them.) The combined tensile and compression forces of the peroneus longus and posterior tibial muscles on the bones of the plantar foot are probably some of the largest contibutors to the interosseous compression forces that exist between the navicular and cuboid.

    Great discussion! Thanks Michael!:drinks
  12. efuller

    efuller MVP

    I said that they would tend to move apart when there is tension in the posterior tibial tendon. However the strong ligamentous attachments will tend to prevent that separation. That is consistent with the fact that there is little motion between the bones.

    (Tension in the posterior tibial tendon will pull the navicular proximally, the talar head is in the way of proximal movement so a force couple that will tend to internally rotate the navicular relative to the talar head. This will cause the navicular to slide around the talar head and pull the cuboid with it.

    I think you are focusing too much on the relationship between the cuboid and navicular. This is far less important than the interactoin between the cuboid and calcaneus and the relationship between the talus and navicular.

    This is because the major forces are anterior posterior or dorsal plantar in the foot at heel off. There is very little medial to lateral force. To get compression between the two bones there has to be something pushing them together. There is nothing pushing the navicular toward the cuboid or vice versa.

    The Achilles tendon tension creates a plantar flexion moment on the rearfoot. To keep the rearfoot from plantar flexing on the forefoot there has to be a dorsiflexion moment from the forefoot acting on the rearfoot. So, tension in the plantar ligaments acting on the navicular and compression from the navicular acting on the talus will cause a dorsiflexion moment (force couple) that will resist plantar flexion of the reafoot relative to the forefoot. This also occurs at the CC joint with tension in the plantar ligaments and compression forces from the cuboid acting on the anterior facet of the calcaneus.

    That is why I think there is little compression force between the cuobid and navicular.

  13. Sorry for the miss quote When you said tend to move appart.

    I put this in a early post and should have finished with a sentance about motion.

    Yes very important thanks.
  14. your welcome took awhile to get going.

    How would one go about free body diagram analysis of this ?

  15. Michael:

    Here is your project for the weekend: free body diagram of the cuboid as viewed within the frontal plane. The following tutorial will be a good place to start your learning.

    Free-body diagram tutorial
  16. During my breakfast this Saturday morning, I pulled the copy of Sarrafian from my library shelf to see whether there was a consistent articular facet between the navicular and cuboid that would give an indication of whether compression forces exist between the navicular and cuboid. Here is what Sarrafian says:

    And, Michael, here is a good starter example of a free body diagram of the cuboid for your weekend project.:drinks

    Attached Files:

  17. Thanks Kevin I´ve been drawing away this afternoon and looking at the tute. See what I come up with but I will admit the head is starting to hurt a little.
  18. Nice work, Kevin. :drinks
  19. Ok here´s what Ive been able to add on to your diagram Kevin

    I used your picture and information and added a few things which I think would change the forces between Cuboid-Navicular.

    I´m not sure how to show COM as It would come from different places so I left it out maybe a big mistake?

    Look forward to see what you think I´ve missed etc.

    Attached Files:

  20. efuller

    efuller MVP

    The difficulty I have with the diagram is something that is not in the picture. The forces are properly labeled. If there is a compression force from the navicular acting on the cuboid there must be a compression force from the cuboid acting on the navicular. (Newton's 3rd law. ) So, the navicular would tend to accelerate away from cuboid unless there is something applying a medial to lateral force on the navicular. What is supplying that force? The peroneus longus tendon attaches to the base of the first metatarsal and supplies a medial to lateral force on the base of the metatarsal. The 2nd cuneifrom and 2nd met can apply a force to prevent medial to lateral motion of the netatarsal. Eventually force through these bones will be applied to the cuboid. So, peroneus longus tension will apply direct force to the cuboid and then pull the cuneiforms back toward the cuboid. However, there is not a direct pull on the navicular. So, there will be more compression force from the cuneiforms on the cuboid than the navicular.

  21. efuller

    efuller MVP

    The center of mass can be left out of a free body diagram if weight of the object is very small in relation to the forces applied to it. The cuboid is fery light in comparison to the forces applied to it.

    When you draw a free body diagram you should only draw forces from objects touching the free body that you are diagramming. So, you should not draw in forces from muscles that don't directly touch the bone. (peroneus longus is a very interesting muscle in relation to the cuboid because it applies a force to the cuboid even though it does not attach to it. The cuboid acts as a pulley for peroneus longus.)


  22. Just had a thought about the70% figure. Would that indicate the for 30% of the population there would be a much great indicator of independent movement in relation to the cuboid-navicular ?
  23. The posterior tibial tendon has multiple insertions on the bones of the plantar foot after it sends its main insertion onto the plantar-medial navicular. Many authors have likened the tensile forces from the peroneus longus and posterior tibial tendons acting as "stirrups" on the plantar foot, both tendons wrapping around the medial and lateral aspects of the foot and inserting on the plantar foot to "cinch" the bones together. I would imagine that this is where the majority of the compression force comes from between the navicular and cuboid and between the cuboid and lateral cuneiform.

    Here is a drawing from Sarrafian's book that nicely illustrates how the tendons of the peroneus longus and posterior tibial tendons are designed to compress the bones of the midfoot more tightly together.

    Attached Files:

  24. efuller

    efuller MVP

    I can see how peroneus longus can cinch the midfoot bones (except the navicular) together. This is because the effective insertion is at the most medial aspect of the tendon. The "pulley" forces and the insertion forces are in opposite directions and will compress the bones together. Since there is no attachment of the peroneus longus tendon to the navicular it is left out of the "cinching."

    The posterior tibial tendon does not have a pulley effect on the medial side. The different attachments of the posterior tibial tendon don't have independent muscle bellies, nor do the many distal splits of the tendon slide relative to one another. When there is a pull on the proximal tendon it will pull on all the distal attachments equally. So there is no additional compression of the cuneiforms toward the navicular.


  25. efuller

    efuller MVP

    I don't think so. It is a very interesting question on how or why joints develop in certain locations. A pseudo arthrosis that develops after a fracture the presence of motion between the two fragments is a very interesting thing to think about in this situation. It implies that joints develop, at least in part, because of mechanical stimulus from their surroundings. Just thinking out loud here.

    It might mean that 30% of the population can't have compressive forces between the navicular and the cuboid.

  26. Eric:

    This effect of the PT tendon could be active but is more likely to be a passive force simply acting to restrain the movement of the plantar aspects of the bones of the midfoot away from each other. Pure speculation, of course, but it makes good mechanical sense..... I always enjoy chewing the fat with you.:drinks
  27. Griff

    Griff Moderator

    Midtarsal joint locking: New perspectives on an old paradigm

  28. Griff

    Griff Moderator


    I have a copy. Will email on to you.

  29. And me please, Griff.
  30. I worked with Neil Sharkey, PhD and Steve Piazza, PhD, doing some STJ axis research at Penn State a number of years ago. We got Neil to come out and lecture at one of the PFOLA seminars after my Penn State visit where he described his cadaver walking simulator research (it's a pretty cool machine). One thing that Neil and I agreed on at the time was that it was the kinetics of the foot that mattered more than the kinematics. Neil did his masters at UC Davis at about the same time I graduated from UC Davis and entered podiatry school.

    The idea of a locking midtarsal joint is pure fantasy. It just can't happen in a foot constructed of viscoelastic ligaments, viscoelastic bones, viscoelastic tendons and viscoelastic muscles...a locking midtarsal joint is an impossibility.
  31. Here is a Precision Intricast newsletter I wrote over five years ago, in June 2008, where I discuss whether the term "midtarsal joint locking" is a real idea or another podiatric myth that has been perpetuated from one podiatrist to another for the past half century. This newsletter was later published in my third Precision Intricast Newsletter Book. The notion that "midtarsal joint locking" may not be a valid mechanical way to describe midtarsal joint function is not a new concept.

  32. I thought I would resurrect one of the older threads on "midtarsal joint locking" that we have been discussing now on Podiatry Arena over the past 10 years in order to further discuss and define midtarsal joint (MTJ) biomechanics.

    Suffice it to say that, contrary to what many of us were taught in podiatry school, the MTJ does not "lock" or remain rigidly fixed in one position where the forefoot is dorsiflexed against the rearfoot when we manually apply dorsiflexion load on the plantar aspect of the lateral metatarsal heads with 10 pounds of force during either examination of the foot or negative casting of the foot for custom orthoses.

    Rather, the MTJ and midfoot joints are spring-like mechanisms which will deform more as forefoot dorsiflexion moments are increased. In other words, when we apply 10 pounds of force to the plantar forefoot should we say the MTJ is "locked" when, during running, that same individual may have 200 pounds of force acting on the forefoot and the forefoot has dorsiflexed significantly further on the rearfoot? Of course not.

    The MTJ doesn't "lock" any more than the leaf-springs supporting the rear axle of a truck "locks" when a truck is parked on the street with an unloaded truck bed. As we add more load to the bed of the truck, the leaf-springs of the truck deform further. In addition, as we apply even more load to the truck bed, the leaf-springs deform even further. Would it be appropriate at any time during the loading process of these truck leaf-springs to say that the truck leaf-springs were mechanically ever "locked"? Of course not.

    Rather, in the case of the truck leaf-springs, at a given load, they will deform a defined amount and will come to an equilibrium position where they will remain stable at a given leaf-spring arch height. Increasing the load on the leaf-springs will cause increased leaf-spring deformation until an equilibrium position is reached where they will again become stable, but in a flatter leaf-spring arch height than with less load. Decreasing the load on the leaf-springs will cause decreased leaf-spring deformation until an equilibrium position is reached where they will again become stable, but in a higher leaf-spring arch height than with more load. Every time the magnitude of loading force applied to the leaf-spring is increased, the arch of the leaf-spring flattens further until it reaches an equilibrium position where the arch height of the leaf-spring is then stabilized.

    In much the same way, the MTJ is a spring-like mechanism where the plantar tension load-bearing structures (i.e. plantar ligaments, plantar fascia, extrinsic muscles and intrinsic muscles of plantar arch) will resist deformation loading forces by preventing longitudinal arch flattening within the physiologic loading ranges that occur during weightbearing activities. The MTJ never "locks" but rather the MTJ becomes temporarily stabilized (i.e. the forefoot temporarily stops dorsiflexing on the rearfoot) with each incremental increase in forefoot dorsiflexion moment that is applied either by our hand, during clinical examination, or by the ground.

    Why is this discussion of MTJ "locking" so important? Because previous podiatric authors have not described the longitudinal arch and MTJ as being spring-like mechanisms. Rather we were all taught that the MTJ somehow "locks" which totally ignores the fact that the viscoelastic ligaments, tendons and plantar fascia which restrain MTJ and longitudinal arch deformation will elongate more with increasing load and will never, ever "lock" under increasing magnitudes of tension loading force.

    Let's not be afraid to move on with our knowledge and into the 21st century of biomechanics, no matter how this may not be what we were taught or what the people we respected told us the way the foot worked. Let us not be continually stuck on theories that still remain unsupported by research over 30 years after they were first proposed. The intellectual integrity of our profession demands it.
  33. and to add to the spring idea is the concept of Beam theory - which I had seen discussed in some emails but was reminded of it by an astute Podiatrist a few weeks ago, the pics did wonders for my brain:D

    might be a good place to discuss that

    Euler–Bernoulli beam theory
  34. rdp1210

    rdp1210 Active Member


    I believe your thoughts are pretty much what I was expressing in some of my last posts on trying to define EROM. There is no question that all soft tissues (and bone too) deform with stress. Right now I am studying the textbook "Mechanics of Materials" by James M. Gere. In it, the student has to calculate the strain of all sorts of metal bars, rods, wires, etc under all sorts of load conditions. The ligaments that provide the EROM of any joint are just the same. The general formula for any material is
    change in length = (Force x Length)/(Modulus of Elasticity x cross sectional area)

    I believe some discussion has started already on how do we begin to construct a length tension curve for any joint in any plane. That would be an ideal clinical situation. I am especially interested in how the force/angle-deflection-curve of the midfoot joints change with various STJ positions. This was a conrnerstone of Elftman theory, modified only slightly by Root by admission of it being soft-tissue, and has only been touched on by a handful of researchers since, e.g. Blackwell.

    I think it has been pointed out by myself, many times, and Simon, and others, that the idea of there being such a thing as a rigid orthotic (which terminology persists to this day) is just as fallacious. Just as the ligaments strain during gait, with the forces applied, hopefully not to the point of reaching their plastic region, so whenever we stand on orthotics, they twist and turn and flex until a point of equilibrium is reached. That is why I am doing my current research project, to begin to understand the stress-strain properties of orthotics of different materials, bent into different configurations. I believe that Root deciding on a NWB MTJ casting position was a classic case of serendipity, he did not calculate what the deformation of the foot was, nor of the materials, yet came up with a solution that has had a great amount of success. Because of his very weak hands, he dorsiflexed the lateral column of the foot to what felt like it's EROM, then he formed the orthotic to match this curvature. (When I was still a student, I found that Root's idea of EROM of the midfoot joints, and his disciples idea of EROM were very different.) When no force is on the orthotic, the lateral (and medial) arch of the orthotic had this casted arch curvature, but as force is applied, it bends, to simulate the same distortion that one would expect in the normal foot under loading, as you described above. I found it interesting that my father carved away the muscle belly of the abductor digiti quinti on the cast before pressing the orthotic. Only in the past few years have I come to understand how this modification may give advantage over the standard Root methodology (does it remind you of someone else carving away a part of a cast?).

    I believe that I shared with you recently an email I received from Bill Orien in which he expressed the idea that in retrospect, the term "locking" was not a great term, and they debated at that time whether a different term should have been used. It certainly gives the wrong connotation of total rigidity to the novice, though anyone experienced in mechanics understands this. As I look in retrospect, I believe that the simplified EROM of the MTJ idea fit in with a casting technique, not that it created reality, but it gave a standard by which to judge whether the NWB orthotic had a starting curvature that could flex with the normal flexion of the foot during WB. I propose that we have much work to do in defining EROM concepts and practices and also in relating them to real foot function and also how orthotics help that normal ligament strain to occur in gait -- the trick is to find that goldilocks zone.

    Take care,

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