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Fabio Alberzoni, Podologo
Milan,Italy

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What specifically would you like to know?

There are a number of threads on forefoot valgus and on equinus.

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Craig Payne
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I saw a lot of people with fore foot valgus having a rear foot pronation in stance, a tight triceps and often a extrarotation of hip.
The post about forefoot valgus talk about orthotic but I'd like to understand better how works the patomeccanics.
thank for your attention.
fabio

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Fabio Alberzoni, Podologo
Milan,Italy

Tight triceps and forefoot valgus foot deformity are integrally related. While the current teaching describes tight triceps (equinus) as an entity in and of itself, I have found that this is actually the result of a fixation of the fibula and therefore a secondary effect .

Limitations of fibula translation results in equinus states. The fibula must translate cranially and laterally to allow for the wider portion of the talar dome to dorsiflexion into the ankle mortise. Another effect of the lack of fibula translation relates to an inhibitory signal to the peroneus longus. The peroneus longus directly arises from the fibula head. Since the peroneals normally function as an everter of the foot, (and oppose the inversion caused by the posterior tibial muscle/tendon complex), once inhibited, these functions are either considerably reduced or completely lost.

A foot type with tight heel cords and FF valgus morphology may well be a foot which directs weight laterally as there is no normal peroneal muscle function to balance the inversion created by posterior tibial. Manipulating the ankle can create change ROM as well as peroneal muscle function and restore normal facilitation.

Once manipulated, care should be given to the CFO. Make sure to use neutral RF vs. Varus RF posting. This would only serve to shift weight laterally and prevent normal function to recur. Calf stretching must be encouraged on the part of the patient.

Howard

Howard,

Thanks for your post. Very interesting.

When you say that "the fibula must translate cranially and laterally to allow for the wider portion of the talar dome to dorsiflexion into the ankle mortise", does this mean the whole fibula moves this way? I'm assuming that translating cranially mean in an upwards direction? And laterally meaning away from the tibia, does the proximal head move laterally too, or just the distal end at the ankle joint?

What would cause a limit in fibular translation?

How do you identify a limitation of fibular translation?

What mobilisation techniques can be used to restore normal fibular translation?

Phil

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Phil Marshman
Mackay, Queensland Australia

Forefoot valgus as described and tested by Root is an open chain position that is sighted from a STJ Neutral value that lacks evidence, reproducibility and much interpersonal value.
It needs changing, upgrading or replacement.

It translates into closed chain as the position of the first ray (in this case plantarflexed from the rearfoot) when first approaching midstance.

This test does not explain in any manner what that ray will do from then on in stance or gait.

If one takes this first test (or a similar one like The Forefoot PERM Test in Functional Foot TYping) and from that position supplies a supinatory moment (The Forefoot SERM Test in Functional Foot Typing), one of three things happen to that first ray.
1. It remains plantarflexed (or rigidly resisting vertical) or in fixed valgus
2. It dorsiflexes to just vertical (into a stable position) or "normal"
3. It dorsiflexes above vertical into a dorsiflexed or flexible position (FHL) or in a forefoot varus position

When #3 is in place for a given patient, the leveraging arm and the ability for peroneus longus to perform its forefoot function as a pronator supplying pronatory moments that counter the first ray dorsiflexing after midstance, is inhibited (a la Dr Dananberg) and needs to be primarily addressed.

When peroneus is inhibited and the patient continues to function (i.e. walk), the compensator for P.longus is the triceps.
I therefore agree with Dr D that the equinus is secondary.
His description of what happens to the fibula in this scenario explains this very same phenomena from atop the postural chain (your rotated hip).

The addition of this second forefoot test (once a valgus position is established if you are currently using Root) dramatically improves our understanding of the mechanics and opens up many avenues for treatment including P. Longus training (compensatory threshold training).

I suggest you consider visiting for a few moments Functional Foot Typing which uses two rearfoot and two forefoot tests that unlike Roots exam which is passive involves applying moments to the STJ and first ray in open chain that give the examiner insight on how those structures will function in closed chain.

http://www.podiatry-arena.com/podiat...ad.php?t=69768

I hope this provides some additional insight to understanding and working with Dr. Dananberg's direction for etiology and treatment as this flexible forefoot functional foot type is the most common type and it has little to do with frontal plane STB pronation or the location of the subtalar joint axis which are "red herrings" in this discussion when it comes to diagnosis or treatment.

Summarily, the function of peroneus longus in this common foot type is possibly where Biomechanics should be focusing and not to its compensators, like the STJ Axis, the Triceps and the frontal plane of the STJ.

Dennis

Phil,

The entire fibula moves...and this is definitely a palpable motion. Feel the fibula head on the lateral side of the leg. Dorsiflex the ankle and if normal, the head moves cranially.

There is a shelf on the proximal tibia, and I think that when the fibula cannot translate, it abuts this portion of the tibia. Once released, ROM in the ankle returns to normal, as does fibula translation and peroneal facilitation.

For videos of this manevuer, go to www.vasylimedical.com and search for these videos. I am a consultant to this company.

Howard

Hi Phil

1. When I assess a limb and its joint the simple questions I ask is should it move? Does it move? If it doesn't why not?

The fibula should move, not a huge amount, but it will also have some degree of stiffness relevant to each individual. Stiffness at a level where there is quite strong resistance to a light but firm single application of, say anterior to posterior pressure, from the thumb may indicate a need for some mobilising work. Equally, restricted flexion at the ankle joint might also indicate fibula mobilisation to be done.


2. Weight bearing dynamic motion of the fibula includes:

1 posterior / anterior and anterior/posterior at both the inferior and superior fibula heads
2 External rotation
3 Caudad towards the floor
4 Cephalad, towards the head

All these motions occur within the gait of an individual and comprise some of what are called accessory glides. Without these glides joint congruency tends to be lost within the mortice in gait in gait, one consequence possibly being restricted ankle flexion in gait.

3. A number of different techniques exist to address increased stiffness in fibula motion. The following is a basic Maitland approach for caudad and cephalic motion that can be simple to apply and quite effective. It is mobilisation, not manipulation style.

1 To generate a passive cephalad motion of a stiff fibula you can apply an oscillatory force to the inferior tip of the inferior fibula head which will release the stiffness and move it upwards.
2 To generate a caudal motion to a stiff fibula you use the calcaneal fibula ligament to draw it downwards by oscillating the calcaneum into end ranges of inversion. This is dependent upon an intact calcaneofibula ligament being present.

In addition there are Mulligan Mobilisation With Movement techniques that are used and Paul Coneelly has some very effective techniques which I use as well. I tend to use any of these dependent upon what I find I'm dealing with.

All of these are mobilisation types.

Manipulative techniques can also be applied but they are not my preference. I'm sure David W will also have something to add from a chiropractic perspective.

Hope this helps

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Are you asking why you would see pronation of the STJ in late stance phase, specifically just before or just after heel off?

Eric

eric...thank you for your question and excuse me for my big delay but I was really busy studing my last 2 exams...promoted!
The patients report a pain in fascia's area and in late mid-stance an important pronation explain this.
thank you if you can explain me....I understand that my knowledge is a very rigid Root type...

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Fabio Alberzoni, Podologo
Milan,Italy

@drsha...
could you explain me better about...
*The Forefoot PERM Test in Functional Foot TYping
*The Forefoot SERM Test in Functional Foot Typing
I still have to study your link but I took a look and seems very interesting!thank you!

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Fabio Alberzoni, Podologo
Milan,Italy

The rigid forefoot valgus foot type was described by Root. Part of what he described was a foot that tended to supinate when the forefoot hit the ground after heel strike. Later, in the stance phase of gait, this foot showed pronation of the STJ. Root attributed this pronation to the peroneal muscles. I agree that it is the peroneal muscles, but not with the rest of Root Orien and Weed's explanation. My explanation is that the rigid forefoot valgus foot type has a laterally positioned STJ axis where the medial forefoot is on the supination side of the STJ axis. That is when you, or the ground, pushes upward on the first metatarsal head, the STJ will supinate. Conversely, the foot with an average or medially positioned STJ axis will pronate when you push up on the first metatarsal head. In the rigid forefoot valgus foot, the early supination would continue unless something stopped it and this foot would get many sprained ankles. The body unconsciously uses the peroneal muscles to prevent the sprained ankles from happening by pronating the STJ.

As the STJ pronates, there will be a tendency to increase force on the first met head and hallux. This will tend to increase tension in the medial slip of the plantar fascia. This is how you could get plantar fascial pain in a rigid forefoot valgus foot.

Let me know if you want more detail.

Eric

Fabio

here's my reasoning to your question

Further to what Eric and Howard have written: When a person has a valgus forefoot or low 1st ray that is stiff to dorsiflexion by GRF and or a lateral stj axis then, you will often see that in an effort to avoid inversion sprains due to potentially excessive supination moments the foot is everted and abducted/externally rotated i.e pronated thru swing phase. often you will find this foot has an equinus ankle so this action also assists ground clearance.

At foot strike there are two things happening, 1) the foot is abducted relative to the direction of progression and so the GRF shear force tends to produce greater pronation moments. 2) the 1st ray dorsiflexes relatively early since the medial foot contacts the ground before the lateral aspect and so the peroneals, which are already firing and shortened are further tensioned by the dorsiflexion of the 1st ray i.e. tensioning the peroneals increases pronation moments about the stj and at the wrong time.

The prescription for this is lateral forefoot post with 1st ray c/o plus mobilising of the ankle and fibula as Howard said.

Now the ankle has greater dorsiflexion rom the foot can clear the ground and as there is lateral support the CNS recognises the peroneals do not need to fire early to prevent inversion sprains and the 1st ray dorsiflexion moments are much less and later in the stance phase and so peroneals do not produce excessive pronation moments and they are not applied to early. Therefore the foot posture is now not pronated.

Regards Dave Smith

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Descartes seems to consider here that beliefs formed by pure reasoning are less doubtful than those formed through perception.

Are you and Eric trying to convince this student that with this laterally deviated STJ axis that the rearfoot of these feet can pronate (move to beyond vertical in stance or gait) on the frontal plane?
I argue that they cannot.

I argue that there is no rearfoot pronation produced by the peroneals. There are pronatory moments in play but no pronation.

Also, are you posturing that the peroneals have some kind of intelligence where they are firing to "prevent ankle sprains"?

In reality, the peroneus muscle engine, when it fires doesn't know whether it will be a rearfoot or forefoot pronator. It doesn't know what percentage of its physical force will be applied to the rearfoot or the forefoot, it just fires.

How they affect the foot is determined by the architecture and the posture of the foot, foot type-specific, not by any schooling that the peroneals have been exposed to.

The equinus present in these feet is positional as well and not due to some peroneal thought process. It is compensatory for the first ray that is stiffly resisting dorsiflexion on the total ROM of the ankle joint on the sagittal plane.

These feet are relatively rare and they are not pronated as you ask this student to envision. In opposition, they are inverted from vertical in their pronatory EROM (RF PERM) position and their first rays are plantarflexed in their supinatory EROM (FF SERM) position.

Their architecture determines how the peroneus longus will impact them in closed chain.

Dennis

Does the peroneus brevis or longus tendon have a stretch reflex? Could this be a mechanism of lateral sprain prevention by the peroneals?

Does the CNS have control over muscle use? e.g timing? You have said, in reference to the peroneals, "it just fires". But why would't the central nervous system actively recruit the peroneals to pronate a laterally unstable foot?

I've had very good results treating peroneal tendon pathology with forefoot valgus posting. Invariably there is a noticable relaxing of the peroneal tendons immediately.

Maybe that "some kind of intellegence" you suggested is the CNS?

Phil

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Phil Marshman
Mackay, Queensland Australia

I didn't want to cause such a bicker but it seems me really interesting.Thank you everybody
In the patient that I've in mind there's a subluxation of peroneus longus's tendon but is this caused by sprain,early firing,both,instability??
Anyway in my opinion the only thing that now I'm sure is firing is my CNS!!!

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Fabio Alberzoni, Podologo
Milan,Italy

The position of the axis is independent of range of motion. Some feet with laterally positioned STJ axes will have lots of eversion range of motion. Other feet will not.


The CNS controls the peroneal muscles. People choose not to sprain their ankles by firing their peroneal muscles. When you examine an ankle sprain you should assess for an avulsion fracture of the styloid process.



A muscle that crosses two joints will have an affect in relation to its lever arm at both of those joints. When peroneus longus contracts its tendon will simultaneously create a plantar flexion moment of the first ray and a pronation moment at the STJ.

Ok Dennis, explain how different foot types change the action of the peroneal muscles.


I agree that a forefoot valgus foot that supinates the STJ is relatively rare. However, there is a difference between a partially compensated rearfoot varus ( inverted from vertical in their pronatory EROM (RF PERM) position) and a "rigid forefoot valgus foot." The Coleman block test is used to figure out which of these foot types you have when you see an inverted calcaneus in stance.


Eric

I did write out a detailed response but then I thought - 'do you know what, I can't be bothered with all the aggro'

regards Dave Smith

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Descartes seems to consider here that beliefs formed by pure reasoning are less doubtful than those formed through perception.