Blounts KAFO Responses

Blounts KAFO Responses

keri blythe

9/23/2002

Many thanks to all who responded! There were a tremendous number of
individuals eager to share their experiences, and I gained some very
valuable insight.

The overwhelming majority of those who responded are using the medial
upright KAFO for treatment of Blounts Disease with the primary rationales
being:
- The mechanical forces applied by a lateral upright KAFO stress the medial
compartment of the knee too greatly.
- The medial upright KAFO concentrates the corrective force over the area of
the deformity (proximal tibia) rather than the knee.

I have included the responses with names removed for those interested in
reading through them. Thanks again for all the information.

Keri Blythe
NCOPE Resident
O&P Clinical Technologies
Gainesville, FL


ORIGINAL POST:
Hello List,
We have a 1 1/2 year old boy with Blount's disease. All the literature I
have been able to locate indicates that the KAFO for treating this condition
should have a medial upright attached to the shoe, a thigh cuff with a
medial pad over the knee, and elastic pulled snugly around the lower leg to
provide corrective force as the child grows. We fabricated two orthoses in
this manner and sent him back for follow-up with his referring physician.
The doctor has requested that we fabricate a device with a lateral upright
and lateral corrective force provided by elastic at the thigh and ankle.
Has anyone else been treating Blount's with this type of device or something
similar? This seems very counter-intuitive to me and the others in our
practice. If you are familiar with this course of treatment, is there any
literature to indicate that it is more or less successful than the
traditional Blount's KAFO?
Thanks in advance for your help - I will post a summary of responses.




RESPONSES:
Keri since I invented the KAFO that you described, I would have to agree
with
you. The mechanic would be to great over the knee joint in the design that
the
Doc described to you.


I've fabricated them with both medial and lateral sidebars over the years.
The most effective force vectors can be applied with a medial sidebar (my
preference); however,
one can certainly achieve a three point force system with a lateral sidebar
with a static cuff at the apex of the tibia vara and opposing adjustable
forces on the medial
side. To effect tibia vara reduction with a lateral sidebar you will
gradually move the static band medially and at the same time move the
stirrup.shoe laterally and the
proximal band laterally. It works, it's just not the convention or as
intuitive as the medial design. I fabricated lateral sidebar Blount KAFO's
for a now retired pediatric
orthopod for nearly 20 years at the Univeristy of Wisconsin. His partners
used the medial design. They both worked quite well.


the device your physician is requesting would be more appropriate for
genu-varum, than blounts desease. Since Blounts desease occurs at the tibial
epyphsial plate you have to focus the corrective force on the proximal third
of the tibia and avoid excessive pressure across the knee joint space.
That type of orthosis focuses the pressure across the joint space and all
thought it will apear that you have acheived some sort of instant
correction ususaly you are just blowing out the medial joint capsule.
I think Ron Sutton has written the definitive work on the subject, and it
was published in the JPO.


Here at the Houston Shrine Hospital we see, fabricate and fit numerous
Blounts kids. We provide a device similar to your first description, but
with some modifications.
We use a static plastic KAFO with a mdeial bar, and free motion ankle joints
such as Gillettes, or Gaffenys. We attach a 6 elastic gusset material as a
pull over, to pull the knee medially to the medail wall of the KAFO. The
lateral side of the thigh and calf sections are trimmed away. We have had
good success with this design.
The design your MD is advocating.....well is the old way.
I can scan and send phtos if you like.


I have not heard of this either. We have a fairly large pediatric
client base and traditionally have used double uprights without knee
joints. With a medial pull calf cuff, knee pad and medial t-strap. When
dealing with bilateral KAFOs a de-rotational butt strap is usually
required. Good luck.


I've made a couple of Blounts braces similar to what you did with the medial
single upright attached to the shoe. I guess the only real advantage to
having the uprights laterally would be that there would not be a problem of
them hitting together during standing/ walking. If you were to make lateral
single upright orthoses, you could attach a custom molded lateral calf cuff.
On the upright proximal the knee, leave it straight. There will be gapping
until the metal upright is pulled tight with elastic on the thigh. It would
be the same 3 pt pressure system, just reversing the push/ pull mechanism.
I don't know if it would be biomechanically superior or not. Try it and
find out...Let me know if it works better.


Call Shriner's


We have made several pairs of orthoses for Blount's patients and they are as
you have manufactured. If the doc wants them the other way - that is
medical mal-practice. Do them your way!


Not me. Medial upright, polypro thigh and afo sections, free ankle. Drop
the lateral proximal AFO section down farther than you normally would. This
to ensure a good purchase with the lateral corrective elastic strap. If I
were you I would speak with the Doc. Just explain your concern, usually
they are quite receptive. Good Luck.


Blount's is, for our purpose, extreme genue valgum where the tibial
plateau is medially worn due to abnormal alignment
of the knee to the point where the plateau is worn to a point. At a
minimum you use lateral side bars with a laterally directed corrective
force at the knee. I find it hard to believe that an infant has a true
Blount's disease due to his lack of ambulation.

My note concerning Blount's disease was incorrect. I stated it was a
genu valgum deformity but it is not--it is a genu varius deformity
(bowing laterally). I would still use a lateral upright with plastic
thigh and calf sections.
I woke-up this morning with this on my mind--I apologize for the error


Actually, you will need a double upright metal and leather KAFO with a
medial T strap, lateral pull pad (correcting force on the tibia) and a
condylar pad with a free ankle and free knee. I've treated several kids with
this and it has been very successful. If it's severe, use a Night A frame
at night along with the KAFOS during the day.


Sounds to me like the Doc just wants to reverse the points of pressure from
a medial base with valgus pressure knee pad to a laterally based valgus
corrective force with closures proximally and distally. The goal can still
be achieved but the standard medial bar KAFO would be more easily donned,
cosmetically appealing, and, most importantly, easier for the caregivers to
adjust and monitor the patient's correction by counting the holes in the
leather knee pad straps or with progressive marks on Velcro straps if used.
I'd suggest to the Doc that the standard KAFO be used for these reasons and
ask him to provide similar arguments for the laterally based design he has
in mind.


The Blount's braces we make are exactly the same as yours with one exception
on the elastic strap; we place ours at the knee. In the past we have made a
set of reverse Blount's with lateral uprights but the legs were bowed in not
out.


Only kind I've ever seen or fabricated was with a medial upright and
attached to the shoe.


I have made some KAFO's for very small children and have attached it to the
shoe and use straight bar stock for the upright(no KJ) while using a free
ankle joint. The little guys aren't slowed down by the lack of a knee joint
and increasing correction is simple.


When I worked at the Hospital for Sick Children in Toronto, we used
to make KAFOs for Blount's and hypophosphatemic rickets. We used a medial
bar, with straps at the apices of the deformity, above and below the knee,
pulling into the medial bar. The proximal and distal counterpressures were
provided by the plastic in the proximal medial thigh cuff and just above the
medial malleolus in the AFO section. We were careful to align the calcaneus
with the tibia and post the foot medially, so that as correction was
achieved, the calcaneus would be vertical and not in valgus. These worked
well. Good luck!


In our experience, the diagnosis of Blount's disease is questionable at this
age because normally the radiological signs are not present. However,
whether physiologic or Blount's is purely academic if the MD wants to treat
it as such. Typically we treat genu varum at this age with a Blount's night
brace which provides correctional forces for the varum as well as the
commonly associated ITT. In older children where Blount's is confirmed by
x-ray or where they have a lateral thrust we use a single lateral upright
without a knee joint. This provides a lateral strut and a push as a
correctional force.
It is important however to follow-up these children at frequent intervals as
you must reshape the upright to keep up with their growth correction. With a
medial upright, it's simply a matter of tightening the strap. So why use
lateral? We have found that the laterally placed thigh band can be placed
higher thus providing a longer lever arm. It is more comfortable having a
strap passing close to the perineum then a rigid band. For 20 years I used
medial, and for the last 7 used lateral. Subjectively I'd say the results
have been equally successful. Offhand I don't know of any literature to
support it.


All Blount's KAFO's I've done have been with medial upright (which can be
bent into valgus position over time) with cuff around the knee pulling it
into valgus


We hav done a few of the KAFOs that you fit on your patient. I have seen
and read about the type that your Dr. has asked for. It is still a
correct 3 point pressure system. If I remember correctly it had a
telescoping pad at the knee to apply the corrective force. I like the
medial upright because you can distribute the corrective force above and
below the knee. If I can find where I saw this KAFO I will be happy to
fax it to you.


I have treated blounts with traditional meatal and leather KAFOs, as well as
KAFOs with the lateral elastic. The orthoses fit and functioned weel,
however I have changed to using the Tampa Shriners plastic and metal design,
documented in JPO by Janet Marshall. Janet had a very large number of
patients, understands Blounts well, and describes their design well. I read
the article, heard her present at ACPOC, and spoke with her at length on
this.
      Following the Tampa Shriners design, I use articulating free motion
pedi Tamarack ankle joints, extended proximal lateral varum control flange
on the AFO section, extended distal medial flange on thigh section as a
hold, and proximal lateral thigh hold (somewhat narrow m/l thigh cuff). We
use a drop lock knee bilaterally, but encourage to keep the knee extended
for maximal correction. We have the patient use it full daytime to control
during weight bearing (when deformation is greatest). I find the most
critical part is to mold in maximal correction, as well as to mold the
femoral section as a narrow m/l to secure proximally.


I too just last week had the same request you had. I too am befuddled as to
the biomechanical principles involved. I eagerly await the responses.


I think Terry Supan, CPO, FAAOP published a paper on this several years ago.
Contact him for more details at


Bow legs:
It is medial with pressure padding on the thigh and the ankle and a elastic
strap around the knee.
It lateral with padding on the knee and and elastic around the ankle and
strap around the thigh.
The last one makes more sense since the problemto correct is below the knee
in the epyphyses of the tibia.
Type Blount disease into yahoo and google and wonder.
Succes


The dr. is mistaken and needs a kinesiology and biomechanics lesson.
Fillauer should have printed literature for the dr. to read.


The main reason for the medial upright and medial
condylar pad is to stabilize the knee joint and
prevent excessive valgus force at the joint while
trying to correct the tibial varum inherent in the
tibia between the medial tibial condyle and the medial
malleolus. If you make this like the doctor is
requesting, you will tend to stretch out the medial
collateral ligaments and injure the knee joint. The
medial knee pad also helps to focus the corrective
force along the bone distal to the condyle, yet
proximal to the ankle joint.
The literature I have seen states the upright should
be on the medial side. If you are unable to find this
article, please let me know. I think I have a copy of
it somewhere and I will look for you if you cannot
find it elsewhere. Hope this helps.