Orthotic Prescription with Hx of ankle facture

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Hi everyone,

I had a patient today (female ~40 yrs) wanting a new pair of orthotic devices as her current EVA devices were worn through and appeared to be no longer providing enough support/control.

The patient had previously factured both the medial and lateral malleoli LEFT (10 years ago) and presented with anterior ankle pain. on the left side, non-WB STJ eversion was normal however inversion was limited to about 10 degrees and AJ ROM was also limited to around 5 degrees of dorsiflexion. non-wb measurements on the right were normal.

RCSP was 2 deg inv (L) and 0 deg (R)
NCSP was 3 deg inv (BF)

There was also about a 5-6 degree forefoot valgus in BF with a plantarflexed 1st ray. During gait the patient seemed to noticably invert further after heel strike before pronating during midstance, during which time the forefoot was quite splayed - the toes also appeared to be quite exteded during this phase of gait.

The overall footype is very cavus.

I should mention that the patient wears MBT shoes with a rocker sole. The shoe seems to have quite a large intrisic heel lift also.

I havent had a lot of dealings with prescribing devices for people with such history/presentation and am a little unsure as to what to prescribe.

I was thinking of prescribing more of an accomdative deivce with minimal arch fill to contact the very high arch, pouring vertical and possibly a lateral flange to limit the excessive inversion after heel strike, however her STJ inversion is already limited on the left side so is a lateral flange a contradictory measure?

In regard to the Ffoot, something like a reverse morton's extension to allow the 1st ray room to plantarflex or an extrinsic EVA foorefoot post to accomodate the fairly large valgus?

Has anyone had experience with the MBT rockersoles before? I am also wondering if I should prescribe an additional amount of heel elevation to accomodate for the raised heel of the shoe.

Any input/suggestions/discussion are/is greatly appreciated

Cheers

 

First question. Are you treating any actual symptoms, or just a range of orthopaedic findings? If the latter - does this patient actually *need* new orthoses?

If the former, then I am going to assume there is some pathology in or around the ankle joint. One must assume some post traumatic osteoarthritis has occured in the presence of significant cavovarus and bimalleolar fracture. Weight-bearing angle and base of gait views of the foot and ankle are hence mandatory to establish at least a provisional diagnosis.

If you are to seeking to 'accomodate' the cavovarus - then I wonder what is the point? However, if you are wishing to exert some kind of 'functional' correction to this situation, then a Coleman block test will assist in knowing if the cavovarus is reducible at the subtalar joint. If this is possible, then suitable functional devices can be prescribed.

Placing a pronation moment across the STJ (eg extrinsic FF valgus posting, lateral heel skive, Denton modification etc) and subsequently reducing any excessive ankle varus that might be present would seem sensible, if radiographic and examination findings correlated with the diagnosis.

LL

 

sorry, I should have mentioned that the patient has had radiographs which confirmed OA in the ankle joint.

I have never used the Coleman block test but I gather that it is used to determine whether or not a FF valgus is the cause/contributer of RF varus?

 

"If you are to seeking to 'accomodate' the cavovarus - then I wonder what is the point? However, if you are wishing to exert some kind of 'functional' correction to this situation, then a Coleman block test will assist in knowing if the cavovarus is reducible at the subtalar joint. If this is possible, then suitable functional devices can be prescribed." Lucky lisfranc's quote.

lis franc is right in his comments, i feel in most cases that i have came across, osteo-arthritic degenerative changes will have resulted in massive impengements arount the distal antero aspect of the ankle from medial to lateral, hence taking to mind the bimalleolar #, with fibrosing of the ligaments around the tibio-fibulartalar area this particular patient will require a lot of accomodative benefits from the orthotic device. cavovarus will do with a lot of shock attenuation as well.

Increased control (polyurethane orthotic with lateral heel skive, 26mm heel cup, medial flange, lateral flenge, poron for added cushion ), thereafter functionality will be enhanced.

the ff valgus i did not catch whether its flexible/rigid, so lets hypothetically analyse this: normally a flexible FFV is one in which the MTJ has suffiecient ROM to compensate for the everted forefoot and a rigid one does the opposite, so instead the STJ must supinate to bring the forefoot to the ground(hence the cavo varus) i am going to assume the FFV is rigid but the restricted motion of the MTJ, should at least have contracted toes of which in this case its not( maybe its in the process.....extensor substitution). Are there any calluses under the 1st and 5th met heads and lateral heel area???, sesamoditis, chronic inversion ankle sprains...this probably explains the fractures.

just a question...was there any previous attempts for othopedic correction of the fractures???.

i hope this helps to the discussion Delpod, you are on the right track matey.


Whose foot is it anyway........

 

Regarding the comment, does she really need another pair. If she is asking for another pair, and she feels that the devices are helping her, then I would go ahead and make her another pair. Given the patient info bleow, I would also feel that there is a high probability that an orthotic should help this patient.

That is a pretty good description of the classic rigid forefoot valgus foot. This type of foot also tends to have a laterally deviated STJ axis. The late stance phase pronation is usually the result of the peroneal muscles being recruited to increase pronation moment at a time around heel lift as the Achilles tendon is increasing supination moment.

You should also look to see if the peroneals are constantly contracting in stance. This is seen in more extreme versions of this foot type. My version of the coleman block test is to ahve the patient stand and ask them to evert and look at the calcaneus and lateral forefoot. Does the calcaneus evert? Does the lateral forefoot lift off of the ground. This tells you if there is eversion range of motion available.

Was the ankle fracture from an inversion injury. A foot with a laterally positioned STJ axis will tend to invert very easily. In terms of prescription a lateral flange will not help as much as a forefoot valgus wedge (either intrinsic or extrinsic.) Also a forefoot valgus extension in place of a reverse Morton's should be considered. Look at the eversion height available when the patient is in stance and make the valgus forefoot wedge not more than that height. You could also consider a lateral heel skive. If the problem is over supination, then you could add more arch fill and lower the medial arch of the device.

There was another discussion of the MBT shoes on the arena. The short version is that some people love 'em and others hate 'em.

A lot of my advice above is based on the assumption that this person has a laterally positioned STJ axis and this leads to lateral ankle instabiilty. The history of an ankle fracture is consistant with this. There is only so much you can do without seeing the patient.

Regards,

Eric

 

I failed to mention... I think the FF valgus is more a ridgid type. Also what you have described above is almost exactly what the patient's foot is doing in gait which coincides with this. As for contraction of the toes to accomodate for restricticed motion of the MTJ...possibly the extension of the lesser toes (which i talked about in my inital description) was part of this? (toes extending just prior to clawing/grabbing at the ground due to instability in the FF??)

 

Firstly Eric, thank you also for your input! You are spot on, the patient does feel that she needs another pair as her previous pair helped with her pain up until recently and she now feels they arent as "supportive". Also from my point of view, her foot type and medical history certainly warrants another pair of orthoses.

I did not check the personeals for contraction during stance. what technique do you use for this eric?

In regard to you version of the coleman block test: when you say get the patient to evert...i guess if the lateral FF lifts off the ground it suggests that there isnt MTJ ROM? Or are you talking about eversion (of the calc.) through the STJ

From the patient's description of the injury: there was a loss of balance whilst holding her child and her foot was caught in a pool fence so i gather the fracture resulted from an inversion injry.

You made mention of a forefoot valgus extension inplace of a reverse Morton's, i am not familair with this?


So, at the moment based on discussions here in this thread, talk with colleagues and my own thoughts I am leaning towards an intrinsic forefoot valgus correction with a lateral heel skive.

 

Direct observation if the patient is lean. Palpation, if not lean. Requires practice.

When the patient fires their peroneals in response to your request to evert, you can see calcaneal eversion, forefoot eversion or both. Do not make your wedge larger than this height as you might get pain sub 5th met or sinus tarsi pain.

Just take the reverse Morton's extension and grind the medial side to 0 height and leave the lateral side alone to create a wedge.

Cheers,

Eric

 

Thanks for that info eric ^^

I sent away the casts today and ended up prescribing an 18mm lateral flange (can grind it off if it causes discomfort) with 5 degrees of intrinsic FF valgus control bilaterally. I have also asked for a slight 2-5 valgus wedge with a 1st ray cut out (which is basically what you are talking about above Eric, i think). I decided to leave the RF as it is as the patient's RCSP was fairly close with her NCSP and I did not want to invert her any further.

I will post back here with an update as to how the devices are going with the patient in a little while.

Once again, thank you to everyone for providing clear insightful input.

Cheers

 

I would make very sure that the plated, fractured ankle did not heal short therefore creating a structural short limb that cannot be compensated at the ankle due to the arthtritis.

A lift going from the heel skived forward to the MP Joints may be remarkably helpful with her gait.

Apply pads to the old or new device to test or consoder The TIP Test from another thread.
Dennis

 

Hi Dennis, I havent added a heel lift as yet but this can be done aftwewards if necessary. I havent seen the other thread you are talking about, have you got a link?

Cheers

 

Not sure how to create a link but here goes:

The Inclined Posture (TIP) it is in the Sports and Biomechanics Section

:drinks

Dennis