Thank you all for all the help, here are the responces.
The plastic AFO should not be set at neutral. There should be a 0 degree
relationship of the tibia to the floor. The shoe heel height must be taken
into
consideration during the casting for the AFO. There are many different shoe
heights but a standard is about 5/8. Casting boards that replicate the shoe
are
available. I use heel lifts when I cast for the same affect. I first measure
the
shoe that will be used and find an appropriate lift.
Hope this helps.
Al Metcalf CPO
he heel height of the shoe the patient will be wearing is an intrical part of
the afo design for the reasons you have described. This must be considered
when the afo is manufactured. Good communication with the orthotist should
yeild the desired result.
Hi Scott – If my experience is any clue you are getting your AFO’s this way
because that’s what PTs have been demanding. I was taught in school to
account for the heel height when making an AFO. When I started working I
did this, and received numerous calls from PTs telling me that my AFO’s were
unacceptable because the were not at 90 degrees. Explaining the
significance of heel height did not make any difference to these people.
They wanted 90 degrees and they were only going to accept 90 degrees. After
a while you learn that you are beating your head against a brick wall and
damaging your reputation with key referral sources to boot. Now I make my
AFO’s at 90 and nary a complaint for years.
Go figure.
Ted A. Trower C.P.
Ted, agreed. I can see your point. As a new PT I quite likely would have
>been one of the asses complaining. Ideally the tibia should be set to 90
>degrees right?
Absolutely, It’s the afo/shoe system that counts, not either one alone.
>Maybe I’m just being a pain, but I have seen that few degrees make a big
>difference in a few pt’s. I have played with anterior crepeing the shoe to
>compensate? Maybe Im out of line but it seems to work.
>Thanks again.
>Scott
>
This is one of the great advantages of the double stop ankle. The ability
to adjust in small increments for both clearance and stability. If you’ve
ever taken the Oregon Orthosis course they really emphasize this.
Ted A. Trower C.P.
A-S-C Orthotics & Prosthetics
Jackson, Michigan, USA
The best time to plant a tree is twenty years ago, the second best time is
today
You don’t mention where you are getting these AFOs from. If they
are custom fabricated, simply ask the orthotist to cast the patient in
slight plantarflexion (using a footboard facilitates this) so that the
tibial angle to the floor is vertical (or even canted slightly
posteriorly to encourage knee extension). The shoe (i.e. heel height, or
slope) should always be taken into account when making a custom orthosis.
If you are ordering the AFOs out of a catalogue, then you’re
getting what you’re paying for! If an existing orthosis is in too much
dorsiflexion it is hard to remedy, but for rehab purposes you can tape a
sole wedge on the outside of the shoe (anterior portion) to cant the
tibia posteriorly. Remember, an AFO set in too little dorsiflexion can
be fine tuned (i.e. for different shoes) with a heel wedge in the shoe,
but when it’s in too much dorsiflexion (causing a knee flexion moment too
strong for the patient) it’s a bigger problem.
Good luck
Diane Tormey, CO
I usually set mine in neutral since the soft tissue compression compensates
for the heel height.
Use a lower heeled shoe. Lower the heel of the shoe. Heat and plantar flex the
AFO (difficult but possible). Raise the sole of the shoe.
There are lots of options. I find that it is easier to dorsiflex an AFO after
it is finished than to plantarflex it, therefore, I tend to cast in slight
plantar flexion then dorsiflex if necessary.
E. Lydon, C.O.
etain the knee extension to the point of knee collapse, this of course ,
stimulates muscle activation, but that is what strengthening is all about., 🙂
We set are AFO’s to 90 with shoe rise built into footplate of orthosis. I
have seen a lot of AFO’s made completely flat , they tend to rock on shoe
last and cause what you describe.
We also fit hinged AFO’s that are left unarticulated initially until return
of post compartment , they are then articulated. One orthosis acts as two,
maximum stability initially.
Marty Mandelbaum CPO
I would suggest looking for a shoe with minimal heel height. Once you locate
one have each patients family buy a pair for the patient.The other thing you
could do is either have an orthotist work with this patient. We usually take
heel height into consideration when fabricating an AFO for just the reason you
are talking about. I you are using prefab AFOs , then this would justify the
need for custom.
Good luck,
Bill
I would discuss this problem with your Orthotists. When we cast and measure a
patient for an AFO, we always take into account the type of shoe and heel
height prior to casting. Our technician’s always correct the cast so it is
in the desired position prior to fabrication. Finally, at the fitting, we
always advise the patient that the orthosis was fabricated for this heel
height shoe, and changing will effect the function.
I hope this information is useful to you,
L. Dreher Jouett, C
Have your orthotist use a footplate board with a heel differential
that matches the normal heel rise of a shoe. He can use this board
when he takes the cast mold and this should alleviate the
dorsiflexion angle.
As far as the current patients, plastic braces can be heated and
stretched into more plantar flexion without distorting them too
badly. Your orthotist may be able to get an additional 2-3 degrees
by doing this.
Sounds like your patients are being cast/measured with their shoes either
not being worn during the process or not being taken into account. Usually
when I cast my AFO patients, I cover the casting material with a thin
orthopedic polymer protective interface (cheap trash bag), slip the
patient’s shoe over the platic bag, and place him/her at the edge of a
chair with the foot flat on the floor and the lower leg vertical. If there
is a varus or valgus problem at the ankle I can rotate the foot externally
or internally to help place the ankle in neutral.
If the patient can tolerate freer (more free?) motion at the ankle, Marty
Carlson’s Tamarack dorsi assist joints are outstanding. They offer plenty
of dorsi assist (there are 2 sizes, each with 2 levels of pick-up) while
allowing a nice, controlled transition from heel-strike to foot-flat.
Because they are installed congruent to the malleoli they offer more ML
stability than a posterior leaf style AFO; this is usually enough for mose
flaccid strokes.Because the joints are relatively low profile, patients
accept them more readily than some of the other bulkier joint designs.
Better your orthotist should err on the side of not enough dorsiflexion in
the more rigid AFOs. You can always build up a little under the heel of the
brace to move the knee anteriorly.
Yours is a good question and one I encounter at clinic on occassion.
Good luck.
Dave
DM Procter, CPO
When the Orthotist casts the patient, heel height of the shoe must be
considered
to attain the proper
alignment. I will write on my work orders, for instance, AFO, 90 degrees with
3/8″ heel. This will
tell the tech to angle the cast at 90 with a 3/8″ wedge under the heel.
Dennis Lafferty
I have been doing a considerable amount of work with CVA patients in an
acute rehab setting. I have been called on to provide AFO’s to both
control a loss of dorsi flexion strength (drop foot), and knee stability
(quadriceps and/or hamstring weakness) common to many stroke patients.
Much of the knee instability I see is genu-recurvatum in nature, but the
balance between genu-recurvatum and excessive knee flexion can be a fine
line with CVA patients.
One of the things I have found to be critical in the formula to
mechanically enhance knee stability, is starting with certain known
quantities. One quantity which must be established, is the heel height
of the footwear the patient is going to utilize. If the AFO is to be
fabricated to respond to ground reaction forces in such a manner as to
affect the knee and provide a positive outcome, the relationship between
the heel height fabricated into the AFO and the heel height of the
patients footwear must be correlated.
If the AFO is fabricated with a 1/2 inch heel height, and you put that
AFO into a 3/4 inch heel height shoe, you will introduce a knee flexion
moment at mid stance as opposed to a “neutral” or stable position of the
knee at mid stance. Take that same AFO, put it in a shoe with NO heel
height, and you will introduce a genu-recurvatum stress at mid stance, as
opposed to a “neutral” position of the knee at mid stance. One thing to
keep in mind, is that if you are utilizing a solid ankle AFO design, you
are not necessarily changing the dorsi flexion and/or plantar flexion
position of the talocrural joint (i e. ankle joint), you are actually
changing the ground reaction forces as they affect the knee. Because of
the immobilization of the talocrural joint within a solid ankle AFO, the
plantar flexion/dorsi flexion angle does not change. Eliminating the
plantar flexion which is normally induced at heel strike, transfers the
ground reaction force to the next joint in the chain of movement, thus
the knee is forced to flex in an attempt to move the foot to the foot
flat phase of the stance phase in order to achieve stability of the
ipsilateral limb(or more correctly in the case of CVA patients, the
instability phase of the ipsilateral limb). If the solid ankle AFO is
fabricated with the heel height of the patients footwear in mind, that
should eliminate most of the problem.
What can also work to control a severe knee flexion moment, is to
actually place the ankle position of the solid ankle AFO in a slight
plantar flexed position. This increases the ground reaction force that
will be generated to the anterio-proximal aspect of the AFO. The
contraindication is the risk of inducing a genu recurvatum.
What I have been trying to introduce with my patients, is the utilization
of the plantar flexion/dorsi flexion assist/resist joints (i e. bi-cal’s,
double adjustable’s), with a combination of pins and springs. The springs
can be set to enhance wanted motion, and the pins can be used to
eliminate unwanted motions. Both of those settings are very dynamic, and
can be adjusted to accommodate the patients rehab status. Plus, even
though we can introduce the known quantity of a heel height into the
fabrication of an AFO the reality is that patients do and will change
footwear, thus changing heel heights and changing how the ground reaction
forces are transferred through the orthotic system. They will also
undergo a change in physiology, for better or for worse, affecting the
patho mechanics of their gait. These factors can only be accommodated
for in a solid ankle AFO, by re fabricating the AFO with the necessary
modifications. With the P/D, A/R joint, the joint can be adjusted to
accommodate for a wide range of changes and fine tuned for the specific
gait biomechanics of each individual patient over an extended period of
treatment.
I hope this is of some help. If you have any specific questions and/or
comments, feel free to contact me.
Good luck, and don’t give up on the ground reaction AFO. They work real
well in most cases.
Michael Madden BOC(O&P),C.Ped
