Correcting supination

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Hello all - i've a question regarding orthoses prescription variables. 14 year-old girl. Right foot heavily supinated. Cavus - met adductus-like (although x-rays have ruled this out (med add that is). Multiple resultant lateral ligament sprains (netball). Base of 5th chronically tender. Noteable ligamentous laxity. Peroneal tendonopathy present.
Temp eversion strapping has worked well in conjunction with RICE.
In terms of orthoses prescription to provide a more user friendly option rather than Mum strapping her up each time she plays -
any suggestions regarding lateral posting/lateral cast grinds etc....

I'd appreciate any feedback.

Chris

 

Intiuitively, do the opposite of what you would do with a severe pes plano valgus.

Assess with a Coleman Block test to determine flexibility and nature of the cavo-varus.

Treat with such modifications as the Fettig (proximal to 5th MT head), Feehrey (whole 5th ray) and Denton (cuboid) modifications. Alternatively, or in addition, use an extrinsic forefoot valgus post. Do what you can to decrease lateral column stress, but typically this is best achieved through applying valgus correction to the forefoot.

Cavus feet are the hardest deformities to treat in podiatry.

LL

 

Howdy
I like to pour vertically and post leaving the Fft valgus deformity 'obvious' on the Fft platform. ie 1st MPJ on the bench and fifth raised.
Then minimally fill the lateral area. That is, just bring the fft platform to the original positive cast with a curve of plaster. This will give you a definite 'lateral arch' at the fft area.
Grind the shell at 0 degrees and also put a Rft post at 0/0 to start with.
This will balance and support the instability while helping 'normal' pronation.
At first the pt will feel amazingly comfortable-the exact opposite of an 'anti-pronating' orthotic.
What usually happens a few weeks in is the mid foot dorsally around the TMT area or the 1st MPJ will start to hurt-this is when I usually regrind to about 2/2.
If you use a lab (as I do) it is sometimes worthy to try grinding 2/2 or 4/4 into the shell then putting a 0/0 post over it so you can remove it after the initial fitting period.
Don't be tempted to make too big an arch medially as you are not trying to stop pronation, you are suporting the foot laterally.
And don't forget a fluffy yummy forefoot extension pad and a 4mm PFA.
Hope this helps and isn't too confusing.
Cheers
Mahtay

 

Effective Orthotic Therapy for the Painful Cavus Foot
A Randomized Controlled Trial
Joshua Burns, PhD, Jack Crosbie, PhD , Robert Ouvrier, MD and Adrienne Hunt, PhD
Journal of the American Podiatric Medical Association Volume 96 Number 3 205-211 2006

Quote:
Patients with a cavus or high-arched foot frequently experience foot pain, which can lead to significant limitation in function. Custom foot orthoses are widely prescribed to treat cavus foot pain. However, no clear guidelines for their construction exist, and there is limited evidence of their efficacy. In a randomized, single-blind, sham-controlled trial, the effect of custom foot orthoses on foot pain, function, quality of life, and plantar pressure loading in people with a cavus foot type was investigated. One hundred fifty-four participants with chronic musculoskeletal foot pain and bilateral cavus feet were randomly assigned to a treatment group receiving custom foot orthoses (n = 75) or to a control group receiving simple sham insoles (n = 79). At 3 months, 99% of the participants provided follow-up data using the Foot Health Status Questionnaire. Foot pain scores improved more with custom foot orthoses than with the control (difference, 8.3 points; 95% confidence interval [CI], 1.2 to 15.3 points; P = .022). Function scores also improved more with custom foot orthoses than with the control (difference, 9.5 points; 95% CI, 2.9 to 16.1 points; P = .005). Quality-of-life data favored custom foot orthoses, although differences reached statistical significance only for physical functioning (difference, 7.0 points; 95% CI, 1.9 to 12.1 points; P = .008). Plantar pressure improved considerably more with custom foot orthoses than with the control for all regions of the foot (difference, –3.0 N · s/cm2; 95% CI, –3.7 to –2.4 N · s/cm2; P < .001). In conclusion, custom foot orthoses are more effective than a control for the treatment of cavus foot pain and its associated limitation in function. (J Am Podiatr Med Assoc 96(3): 205–211, 2006)

 

In my experience this type of patient is one of the most difficult to treat. When the rearfoot is maximally pronated (passively/NWB), look at the position of the calcaneus to the tibia- or try the coleman block test as previously suggested. If it is still in a varus position, I would not rely to heavily on a foot orthotic (although it is worth a try) given her history of recurrent sprains and peroneal pathology. I would recommend a rigid sports ankle brace when performing provocative activities/sports and consider surgery when appropriate. A hiking boot would be a good shoe selection when not playing sports

 

Treating this patient requires understanding of rotational equilibrium and how ground reactioni forces cause motion at the Subtalar joint. The moment from ground reaction force is determined by the location of the center of pressure udner the foot and the location of the STJ axis. In the patient described above, often the STJ axis is laterally positioned and thus a center of pressure under the foot will tend to be on the lateral side of the axis and this causes a supination moment from ground reaction force. If the patient does not constantly use their peroneal muscles this foot will tend to supinate to the end of range of motion of the STJ. The solution is to increase pronation moment about the STJ. This can be done by shifting the center of pressure further laterally. However, you don't want to pronated the foot farther than the available comfortable range of motion. For this situation I developed what I call the maximum eversion height test. Demonstrate to the patient what STJ pronation motion is. Have them stand and ask them to move their foot as far as they can in the direction of pronation witout moving their legs. You then measure the amount of height that the lateral column (styloid and 5th met head can get off of the ground.) Do not make your forefoot valgus intrinsic post or your forefoot valgus wedge extension higher than this hieght. If you do, you can cause pain in the sinus tarsi or on the plantar lateral surface of the foot. In addition you could add a lateral heel skive and a flat rearfoot post to the device to increase the lateral shift of the center of pressure. I've seen the patients notice immediate relief with a valgus forefoot wedge. It is quite gratifying. So you could use any combination of a forefoot valgus wedge, extrinsic forefoot valgus post in an orthosis and a lateral heel skive depending on how severe the problem is.

Cheers,

Eric Fuller

 

Here are a few observations I have made over the past 20+ years regarding this type of foot:

1. Supinated feet are not hard to treat as long as you understand, like Eric Fuller stated, that you must increase the ground reaction force (GRF) lateral to the subtalar joint (STJ) axis and decrease the GRF medial to the STJ axis in order to decrease the STJ supination-related symptoms. The problem comes in trying to apply other models of foot function such as the STJ neutral model or sagittal plane facilitation model to treating these feet. These models fail at specifically addressing the biomechanics of feet that suffer from supination-related symptoms, the biomechanical causes of supination-related symptoms and their effective treatment. The only model, to my knowledge, that addresses these symptoms is the STJ Axis Location and Rotational Equilibrium (SALRE) Theory of Foot Function.

2. The patient's 5th metatarsal base pain is most likely a peroneus brevis insertional tendinitis. Both the peroneal tendinopathy and peroneus brevis insertinal tendinitis are caused by increased contractile activity of the peroneals due to increased STJ supination moments due to a laterally deviated STJ axis. The laterally deviated STJ axis also causes a decreased length of the peroneal muscle pronation moment arms to the STJ axis which, in turn, will necessitate increased contractile force from the peroneal muscle and increased tensile force within the peroneal tendons to produce a given internal STJ pronation moment.

3. High degrees of metatarsus adductus cause a medial shift of the plantar metatarsal heads relative to the STJ axis which will cause increased STJ supination moment during weightbearing activities (Kirby KA: Subtalar joint axis location and rotational equilibrium theory of foot function. JAPMA, 91:465-488, 2001). Significant metatarsus adductus is commonly associated with supination-related symptoms for this reason. No other theory, to my knowledge, explains the biomechanical correlation of metatarsus adductus deformity to supination-related symptoms other than SALRE theory.

4. These patients may be treated effectively temporarily with a valgus rearfoot to forefoot wedge plantar to the heel and extending anteriorly to the sulcus of the digits. Orthosis prescription includes a lateral heel skive, everted balancing position of positive cast, increased medial expansion plaster thickness of positive cast, valgus forefoot extensions, flat rearfoot posts and lateral arch fill plantar to the orthosis plate. These temporary and/or more permanent orthosis modification work by increasing external STJ pronation moment so that the internal STJ pronation moments caused by increased peroneal contractile activity are not needed by the body to allow plantigrade gait function to occur and allow the body to avoid inversion ankle sprains.

5. Root type foot orthoses routinely fail in treating these patients.

6. Most podiatrists, especially those podiatrists still stuck on Root theories, are so afraid they will "over-pronate" the foot by using the above modifications that they will never be able to effectively treat these disorders with foot orthoses. I believe that this is because these podiatrist were taught Root biomechanics theory in podiatry school that did not address these mechanical issues specifically and have never considered SALRE theory for treating their patients.

 

Actually the Root paradigm can be successful with this foot if the patient was lucky enough to reside on the west cost of the United stats where podiatrists see more forefoot valgus. An intrinsically balanced forefoot valgus orthosis is one of the suggested treatments for this patient. However, if the patient went to see a podiatritst who saw a forefoot varus, the device would be much less likely to work. This is the problem with the root paradigm is that two different practioners can look at the same foot and come up with a completely different measurement.

I'm not as familiar with the sagittal plane paradigm, but I imagine there must be some scenario where they would add a forefoot valgus wedge or post at least some of the time.

Although I would agree that when someone looks at it from an engineering approach that they would be more likely to treat a peroneal tendonitis by attempting to pronate the STJ with a shift in ground reaction force.

Regards,

Eric Fuller

 

Eric:

What I am saying, for example, is that if a patient had a chronic peroneal tendinitis, had a metatarsus adductus but had a perpendicular forefoot to rearfoot relationship and a vertical RCSP, the Root model would teach you to balance the orthosis vertically and add no forefoot valgus extension to the orthosis. Not only would this orthosis not work, but it may even increase the patient's symptoms due to the increase in STJ supination moment this orthosis would create.

However, using the SALRE theory in this patient, where the clinician knows that increased metatarsus adductus is one of the causes of increased STJ supination moment, the next logical step is to design the orthosis to increase STJ pronation moments to decrease the contractile activity of the peroneal muscles and decrease the pain in the peroneal tendons.

The other models sometimes use a forefoot valgus type wedge for different reasons, however, they do not advocate use of rearfoot or forefoot valgus wedging supination symptoms caused by increased metatarsus adductus, to my knowledge. In other words, it is not so much to know that an orthosis modification option exists, it is more important to know when to use that orthosis modification option on the appropriate patients for optimal treatment results.

Would you not agree? I know we are close here and thought the example above might be a good teaching model for the differences between the different treatment paradigms.

 

Kevin,

I do agree. My point was someone who is an adherent to Root theory will say "I've had success with my ortotics, these SALRE guys don't know what they're talking about." SALRE theory would explain the successes and failures of the Root devices with some prediction of which ones failed and which ones succeeded. SALRE also gives a hint of how to modify the device it it does not work. Under Root theory you had to find the "mistake" you made in making the orthosis. The mistake could be the first time seeing a forefoot varus and then seeing a forefoot valgus the second time. The mistake could not have possibly been in the theory . If the symptoms do not resolve under SARLE theory then you did not increase pronation moment enough. Or if the orthosis attempts to evert the foot farther than it can go and you get sinus tarsi pain or lateral column pain then you know you went to far trying to shift the center of pressure further lateral to the STJ axis.

There is an important point from Root theory that should be remembered. All feet are not the same. The problem with Root theory is that forefoot to rearfoot measurement is not a repeatable measure and therefore is not a very good basis for a prescription writing protocol. Any study that examines the effectiveness of foot orthoses has to have a protocol for prescription and fabrication of orthoses that takes into account what makes feet different. For research to progress on the effectiveness of orthoses we need to be able to show that STJ axis location can be found accurately. I believe that it can be. The theory behind this is so simple that I have great confidence that using STJ axis location in a prescription protocol will provide better results than using protocols that don't.

Sincerely,

Eric Fuller

 

Eric:

Good points....as always.

 

Kevin,

I agree with your SALRE theory- however, is a foot orthoses enough in the extremely cavus foot that suffers from recurrent sprains and peroneal injury which cannot be passively ranged out of a heel varus position. Although the proper orthosis is much better than nothing, I typically think beyond the orthosis- namely bracing, shoe modification and/or surgery.

How do you pronounce the acronym SALRE ??

Nick

 

Thankyou all for contributing to this discussion. A few pearls in there. Hooray for this forum. When your a sole practitioner it kind of makes you feel like you've got some help just down the corridor!

Cheers,

Chris

 

Nick:

In order to treat an "extremely cavus foot" that has chronic lateral ankle stability and peroneal tendinopathy, one does not need to move the calcaneus out of a varus position. One only needs to reduce the external STJ supination moments sufficiently so that 1) the patient is less susceptible to inversion ankle sprains, and 2) the peroneals reduce their contractile activity sufficiently so that peroneal tendon pain is reduced.

In other words, persistence of heel varus position with foot orthosis treatment does not preclude successful treatment of symptoms in these individuals. Of course, orthoses are only one component of a successful treatment plan you have outlined above. However, if you gave the patient the choice between having their pain and instability improved with an in-shoe insert, an ankle brace, a visible external shoe modification or surgery, which treatment alternative do you think they would most likely tend to choose?

 

To paraphrase Kevin's answer. You start with the orthosis and then go to the shoes and braces if the orthosis is not enough. Some feet really need a lot of pronation moment to stay plantigrade.

By the way SALRE is pronounced "tissue stress"

Best,

Eric

 

Good one Eric. By the way, for any of you interested, Eric and I coauthored a book chapter titled "Subtalar Joint Equilibrium and Tissue Stress Approach to Biomechanical Therapy of the Foot and Lower Extremity" a few years ago. It is my understanding that the book will be published sometime this year. The concepts of SALRE and tissue stress go hand in hand with each other to help us understand how to appoach mechanical problems of the foot and lower extremity. The concept of treating symptoms relating to supination moments is covered in this chapter, complete with illustrations.

 

One other point is in order here. I don't treat "cavus feet". I treat the patient's symptoms that are associated with their "cavus feet". In other words, the foot orthosis treatment, shoe selections, shoe modifications, physical therapy and/or surgery is not solely determined by the height of the patient's medial longitudinal arch, but more by the symptoms the patient presents with.

Even though this may, on first glance, seem like a small point, it is a major change in philosophy for orthosis prescription. Tissue stress/SALRE theory relies on determining the anatomical structure that is receiving pathological stress and causing injury, determining the type of stress that is occurring (i.e. tension, compression, shearing) and then devising a treatment plan that reduces the magniitude of stress that is causing the patient's symptoms. This is very different from the traditional STJ neutral type orthosis prescription system which is a deformity-based orthosis prescription system and which considers the measured foot and lower extremity structure (i.e. deformities), not the type of injury the patient has.

In other words, I could care less if I can't move the heel out of the heel varus position passively, I am more concerned with the forces involved, with their gait function and how their symptoms respond with my treatment protocol. Of course externally visible foot structure is important, but looking solely at heel position, without considering talar head position or STJ axis location in a patient, will always give the clinician too little information to make the most intelligent treatment choices for their patient.

 

supinated foot posture and orthoses?

Can anybody give some advice as to the best way to treat a patient with lateral ankle pain, peroneal muscle weakness and a supinated foot posture(RCSP 2 degrees inverted, NCSP 4 degrees inverted) with specific reference to orthotic treatment? Would you use a mod Root device with just a lateral forefoot or rearfoot wedge? and would you cast them differently? or cast in neutral? or can anyone direct me to literature which would support the choice of orthotic or how to treat a supinated foot posture?
thankyou!

 

hi,

'Treat with such modifications as the Fettig (proximal to 5th MT head), Feehrey (whole 5th ray) and Denton (cuboid) modifications'

Do you have any literature for these modifications, please?? or maybe even better: how to do them?

 

Re: supinated foot posture and orthoses?

Lateral Skive tech.

http://www.podiatry-arena.com/podiatry-forum/showthread.php?t=37018

Look up the above thread it in the spainish forum but look at thread 2 and 3 The one by Javier read the 2 links ( they are in english) that he provides and then the thread by Kevin Kirby with pictures of the lateral skive tech.

 

lateral heel skive
Intrinsic Lateral forefoot valgus post
Lateral column fill
Reverse Mortons extension
First ray cut away

In severe cases, especially if a neurological deficit is apparent I would combine this with the Richie Brace.