Responses - knee orthosis for femoral nerve palsy
Ted A. Trower
Description
Collection
Title:
Responses - knee orthosis for femoral nerve palsy
Creator:
Ted A. Trower
Date:
10/27/1999
Text:
My original post was as follows:
----------------------
I have just seen a gentleman who experienced a unilateral femoral nerve
palsy post spinal anesthesia. He is now four months post injury and is
getting significant return of function but is still experiencing
uncontrollable buckling of the knee. I was thinking of a KAFO with offset
knee joint and a solid ankle but after seeing him I think he might be able
to get along with less hardware. Is there any knee orthosis that offers
improved resistance to knee buckling in the presence of weak quadriceps?
----------------------
The bulk of responses are clearly suggesting the use of a ground reaction
AFO. I had considerered this but I really hate to lock up a perfectly
normal ankle. This is the reason I was not satisfied with the idea of using
a KAFO. I would prefer to attack the knee directly if it can be effective.
Thanks to all who responded.
----------------------
responses to date (this is in only 18 hours!):
----------------------------------------------------------------------------
--------
These are long shots, but I have had some luck in the past with the OB
extension assist attachment to their offset knee joints although I always
used a dorsistop ankle to add GRF stability in adults. Scott Orthopedics
makes a KO with surgical rubber extension bands that functions similarly.
Finally, in Chicago we used plain old knee sleeves with spiral spring stays
for the Muscular Dystrophy kids nearing the end of their ability to walk.
It was amazing how such a little bit of extension force allowed many of them
to keep walking an additional 6-12 months despite profound weakness.
Obviously, you need to determine how little extension aid will be
sufficient. Good luck!
----------------------------------------------------------------------------
--------
I am utilizing floor-reaction orthoses more today than ever before and
finding that they work quite well for patients whose quad strength is at 3-/5
or better with no evidence of collateral ligament laxity. There are however
right ways and wrong ways to approach the fabrication of the FRO. If you
will contact me, I would be glad to give you the evaluation sequence,
fabrication technique(s), and delivery protocol which should help you (and
your patient) alot!!!!
----------------------------------------------------------------------------
--------
For a guy like this, I like to use a trick I learned from OOS... Maybe a
'floor reaction' AFO would work instead of a KAFO... so cast the AFO section
with fiberglass, maybe in a degree or two of plantarflexion if you think
that it is called for, and cast just a bit heavier than you might usually.
And pull a sock over the completed cast and jam on the patient's shoe, or a
slightly large loaner, and SEE if it is enough support. Knee safe? Then
you can make the AFO with confidence. Knee not safe? Then just finish
wrapping the cast to the perinium and make the KAFO. This way, your patient
knows for sure that that big heavy KAFO is really required, and you did the
best you could for him.
----------------------------------------------------------------------------
--------
Ted - I would be careful with the solid ankle. If you do not allow plantar
flexion range - the lack of it will cause a knee flexion thrust on heel
contact - and will destabilize the knee with out the adaquate quad strength.
I have done a KAFO for a similar condition - used the posterior offset free
knee and a free articulation ankle joint. He had good dorsi and plantar
flexion muscles- so I used a Tamarak. Worked out just fine. If you want to
go with less hardware -- you can trim the footplate to be just a posterior
leaf ---allowing free , low resistance plantar flexion.. The foot section is
important for suspension. If you use just a KO -- they will tend to tighten
up the thigh strap for suspension and that can actually lead to ischemia of
the quad and decrease the return of strength. You could consider an AFO ---
dorsi flexion stop style. I would consider a metal DAAJ joint and a full
stirrup( to a plastic or metal AFO) to provide the support and stability that
may be needed to support from buckeling... AGAIN - allow free plantar
flexion range and motion.
----------------------------------------------------------------------------
--------
Where have you been? Haven't heard from you in forever! I have a patient
with a different Dx, but functionally similar. I recheck him tomorrow in
his pre-fab KO and I will let you know the success/failure. Does your
patient have any function about the ankle? Is the person large or small?
----------------------------------------------------------------------------
--------
Well, normally I would recommend trying a floor reaction AFO but my last
experience with it makes me wonder. I fabricated a FRAFO for a patient who
had weak quads as he didn't want the bulk of a KAFO. When he saw it, he
refused to even try the orthosis because it couldn't possible control my
knee. I have had success with them, however, in the past.
But, if he's getting return, you may want to consider either an OTC or
custom knee extension assist KO. Scott makes one or you can fabricate one
with either bungie cords on outriggers or elastic straps crossing over the
knee(with a knee cap below them). I've also had good success with them as
long as the patient has some quads.
----------------------------------------------------------------------------
--------
Ted, I believe that there is no orthosis for a femoral nerve injury. If he
is unilaterally
injured he can still walk but probably has a difficult time with steps or
rising from a
chair. Perhaps a cane will be of best assistance.
----------------------------------------------------------------------------
--------
Ted: Try polypro thigh +calf with tamrak 85 dfa joint for knee joint,
----------------------------------------------------------------------------
--------
A suggestion might be a Truform lace-up knee support with adjustable knee
flexion stops incorporated w/i the knee jts. If you lace it up snugly, it
provides some resistance to knee buckling, plus you utilize the knee flexion
stop where necessary. I believe it is in 20 degree increments. If you set
it at 180, the knee will still flex somewhat w/i the orthosis, but is still
fairly stable, pending the weight of the patient. It's lightweight and
inexpensive. Longevity not a strong point, especially for the flexion stops,
but if he's progressively having return, this may not be an issue.
----------------------------------------------------------------------------
--------
Is his weakness too severe to benefit from just a ground reaction design?
This sounds like an ideal case for one of those semi-experimental knee
extension assist orhtoic desgins that we have talked about before on this
list...
----------------------------------------------------------------------------
--------
his may be a bit off the wall but what about an anterior floor reaction AFO
with some type of adjustable ankle joint (the Becker joint that looks like an
Oklahoma joint comes to mind) allowing free planter flexion, assuming the
patient has adequate planter and dorsiflexors, and stopping dorsiflexion at 0
to 5 degrees of plantar flexion. But then I am a C.P. not an Orthotist...
----------------------------------------------------------------------------
--------
You might want to try a floor reaction AFO. We used them in Alabama and
now in Texas and they do give the knee support. Hope this helps.
----------------------------------------------------------------------------
--------
Dear Ted: I have just made a KAFO that incorporated adjustable extension
knee joints made by Ultraflex. The joints are somewhat bulky but I felt
that the benefit of walking without a fixed knee outweighed the disadvantage.
I found that placing the uprights inside the plastic helped to reduce the ML
dimension across the knee. If a structural band is incorporated into the
plastic the possibility of eliminating the medial extension mechanism exist.
----------------------------------------------------------------------------
--------
Ted,
We have been using Ground Reaction Ankle Foot Orthoses (Grafos) with good
success. Your client needs to have some quadricep power (at least grade 3)
and the ankle is cast in about five degrees plantar flexion. The GRAFO has
an anterior section. This can be below the knee although many orthotists
take it above the knee. The GRAFO is great for preventing knee buckling
without having to use a thigh shell and knee joints. It works on a three
point pressure system. There is an article on GRAFO's in a recent Journal
of Prosthetics and Orthotics.
----------------------------------------------------------------------------
--------
this is coming from a prosthetist, BUT
1. what kind of muscle strength does he have in his hip extensors?
hamstrings? because using the ground reaction forces, you can stabilize
the knee using hip extensors just like a transfemoral amputee does.
2. maybe there is some proprioception problem, which would be bigger
issue. if you don't know your knee is flexed when you weightbear, then
you are toast.
3. if he does not have good proprioception, then using hamstrings can
cause recurvatum. if he has good proprioception as all skateboarders
know, you can use hip extensors and keep the knee flexed enough so as not
to get hyperextended knees.
----------------------------------------------------------------------------
--------
Hey Ted,
Scott Orthotic Labs phone # is 1-800-821-5795.
Thought this might help.
----------------------------------------------------------------------------
--------
I have used with good success a couple of different knee brace styles offered
from Scott Orthotic Labs. They have one with polycentric knee joints that
incorporates the use of surgical tubing and midsection piece to give a
substantial extension assist that can be adjusted by the tension on the
tubing.
They also have a model that uses a drop lock knee joint, this one is nice
because they use ball keepers on the locks so they can be held above the
joint, and then put down when the person feels weakend or tired. With this
model you are able to release the tension on the knee joint from the tubing
so that the knee can rest at a 90 degree angle for sitting.
----------------------------------------------------------------------------
--------
Consider this;
A laminated ground reaction orthosis, be sure that the footplate is extremely
rigid and extended to the end of the toes. Double action ankle joints that
allow free plantar flexion but resist dorsiflexion. The Gentleman then can
work with you or a P.T. and be taught how to effectively use the orthosis.
The client must be instructed on holding his hip joint on the effected side
slightly forward during stance. He also needs to be trained to allow his
knee to fall into the pretib section of the orthosis, instead of forcefully
hyperextending his knee for stability. That is a waste of momentum in the
opposite direction.
The advantage is you are able to control the knee without the added hardware.
An energy efficient gait is possible without limiting flexion and extension
at the knee, or plantarflexion of the ankle. This also prevents disuse
atrophy of the quads due to locking the knee during ambulation.
I've have used this technique successfully for the last several years and on
my adult
clients I have mostly used a ground reaction orthosis fabricated by Oregon
Orthotic Systems.
Also, if you or the patient is not sure this will be effective try test
casting. Cast the client with fiberglass being sure that the foot and ankle
is at 90 degrees and positioned in neutral alignment, be sure the cast
extends to the end of his toes and is rigid around the ankle, ( but not so
rigid that you can't get the cast off when your finished ). Then put his
shoe on over the cast if possible, if not try a different shoe. Then have
him walk with the test cast in order to simulate the effect of an orthosis.
Make sure that the hip is positioned as mentioned and if it is adequate you
will see the knee stabilized.
----------------------------------------------------------------------------
--------
ted
locking the ankle at initial contact [ heel strike ] might/will increase the
probability of knee flexion . allow plantar flexion at i.t. & you decrease
the amtount of force at the knee
----------------------------------------------------------------------------
--------
Ted A. Trower C.P.O.
A-S-C Orthotics & Prosthetics
Jackson, Michigan, USA
<Email Address Redacted>
----------------------
I have just seen a gentleman who experienced a unilateral femoral nerve
palsy post spinal anesthesia. He is now four months post injury and is
getting significant return of function but is still experiencing
uncontrollable buckling of the knee. I was thinking of a KAFO with offset
knee joint and a solid ankle but after seeing him I think he might be able
to get along with less hardware. Is there any knee orthosis that offers
improved resistance to knee buckling in the presence of weak quadriceps?
----------------------
The bulk of responses are clearly suggesting the use of a ground reaction
AFO. I had considerered this but I really hate to lock up a perfectly
normal ankle. This is the reason I was not satisfied with the idea of using
a KAFO. I would prefer to attack the knee directly if it can be effective.
Thanks to all who responded.
----------------------
responses to date (this is in only 18 hours!):
----------------------------------------------------------------------------
--------
These are long shots, but I have had some luck in the past with the OB
extension assist attachment to their offset knee joints although I always
used a dorsistop ankle to add GRF stability in adults. Scott Orthopedics
makes a KO with surgical rubber extension bands that functions similarly.
Finally, in Chicago we used plain old knee sleeves with spiral spring stays
for the Muscular Dystrophy kids nearing the end of their ability to walk.
It was amazing how such a little bit of extension force allowed many of them
to keep walking an additional 6-12 months despite profound weakness.
Obviously, you need to determine how little extension aid will be
sufficient. Good luck!
----------------------------------------------------------------------------
--------
I am utilizing floor-reaction orthoses more today than ever before and
finding that they work quite well for patients whose quad strength is at 3-/5
or better with no evidence of collateral ligament laxity. There are however
right ways and wrong ways to approach the fabrication of the FRO. If you
will contact me, I would be glad to give you the evaluation sequence,
fabrication technique(s), and delivery protocol which should help you (and
your patient) alot!!!!
----------------------------------------------------------------------------
--------
For a guy like this, I like to use a trick I learned from OOS... Maybe a
'floor reaction' AFO would work instead of a KAFO... so cast the AFO section
with fiberglass, maybe in a degree or two of plantarflexion if you think
that it is called for, and cast just a bit heavier than you might usually.
And pull a sock over the completed cast and jam on the patient's shoe, or a
slightly large loaner, and SEE if it is enough support. Knee safe? Then
you can make the AFO with confidence. Knee not safe? Then just finish
wrapping the cast to the perinium and make the KAFO. This way, your patient
knows for sure that that big heavy KAFO is really required, and you did the
best you could for him.
----------------------------------------------------------------------------
--------
Ted - I would be careful with the solid ankle. If you do not allow plantar
flexion range - the lack of it will cause a knee flexion thrust on heel
contact - and will destabilize the knee with out the adaquate quad strength.
I have done a KAFO for a similar condition - used the posterior offset free
knee and a free articulation ankle joint. He had good dorsi and plantar
flexion muscles- so I used a Tamarak. Worked out just fine. If you want to
go with less hardware -- you can trim the footplate to be just a posterior
leaf ---allowing free , low resistance plantar flexion.. The foot section is
important for suspension. If you use just a KO -- they will tend to tighten
up the thigh strap for suspension and that can actually lead to ischemia of
the quad and decrease the return of strength. You could consider an AFO ---
dorsi flexion stop style. I would consider a metal DAAJ joint and a full
stirrup( to a plastic or metal AFO) to provide the support and stability that
may be needed to support from buckeling... AGAIN - allow free plantar
flexion range and motion.
----------------------------------------------------------------------------
--------
Where have you been? Haven't heard from you in forever! I have a patient
with a different Dx, but functionally similar. I recheck him tomorrow in
his pre-fab KO and I will let you know the success/failure. Does your
patient have any function about the ankle? Is the person large or small?
----------------------------------------------------------------------------
--------
Well, normally I would recommend trying a floor reaction AFO but my last
experience with it makes me wonder. I fabricated a FRAFO for a patient who
had weak quads as he didn't want the bulk of a KAFO. When he saw it, he
refused to even try the orthosis because it couldn't possible control my
knee. I have had success with them, however, in the past.
But, if he's getting return, you may want to consider either an OTC or
custom knee extension assist KO. Scott makes one or you can fabricate one
with either bungie cords on outriggers or elastic straps crossing over the
knee(with a knee cap below them). I've also had good success with them as
long as the patient has some quads.
----------------------------------------------------------------------------
--------
Ted, I believe that there is no orthosis for a femoral nerve injury. If he
is unilaterally
injured he can still walk but probably has a difficult time with steps or
rising from a
chair. Perhaps a cane will be of best assistance.
----------------------------------------------------------------------------
--------
Ted: Try polypro thigh +calf with tamrak 85 dfa joint for knee joint,
----------------------------------------------------------------------------
--------
A suggestion might be a Truform lace-up knee support with adjustable knee
flexion stops incorporated w/i the knee jts. If you lace it up snugly, it
provides some resistance to knee buckling, plus you utilize the knee flexion
stop where necessary. I believe it is in 20 degree increments. If you set
it at 180, the knee will still flex somewhat w/i the orthosis, but is still
fairly stable, pending the weight of the patient. It's lightweight and
inexpensive. Longevity not a strong point, especially for the flexion stops,
but if he's progressively having return, this may not be an issue.
----------------------------------------------------------------------------
--------
Is his weakness too severe to benefit from just a ground reaction design?
This sounds like an ideal case for one of those semi-experimental knee
extension assist orhtoic desgins that we have talked about before on this
list...
----------------------------------------------------------------------------
--------
his may be a bit off the wall but what about an anterior floor reaction AFO
with some type of adjustable ankle joint (the Becker joint that looks like an
Oklahoma joint comes to mind) allowing free planter flexion, assuming the
patient has adequate planter and dorsiflexors, and stopping dorsiflexion at 0
to 5 degrees of plantar flexion. But then I am a C.P. not an Orthotist...
----------------------------------------------------------------------------
--------
You might want to try a floor reaction AFO. We used them in Alabama and
now in Texas and they do give the knee support. Hope this helps.
----------------------------------------------------------------------------
--------
Dear Ted: I have just made a KAFO that incorporated adjustable extension
knee joints made by Ultraflex. The joints are somewhat bulky but I felt
that the benefit of walking without a fixed knee outweighed the disadvantage.
I found that placing the uprights inside the plastic helped to reduce the ML
dimension across the knee. If a structural band is incorporated into the
plastic the possibility of eliminating the medial extension mechanism exist.
----------------------------------------------------------------------------
--------
Ted,
We have been using Ground Reaction Ankle Foot Orthoses (Grafos) with good
success. Your client needs to have some quadricep power (at least grade 3)
and the ankle is cast in about five degrees plantar flexion. The GRAFO has
an anterior section. This can be below the knee although many orthotists
take it above the knee. The GRAFO is great for preventing knee buckling
without having to use a thigh shell and knee joints. It works on a three
point pressure system. There is an article on GRAFO's in a recent Journal
of Prosthetics and Orthotics.
----------------------------------------------------------------------------
--------
this is coming from a prosthetist, BUT
1. what kind of muscle strength does he have in his hip extensors?
hamstrings? because using the ground reaction forces, you can stabilize
the knee using hip extensors just like a transfemoral amputee does.
2. maybe there is some proprioception problem, which would be bigger
issue. if you don't know your knee is flexed when you weightbear, then
you are toast.
3. if he does not have good proprioception, then using hamstrings can
cause recurvatum. if he has good proprioception as all skateboarders
know, you can use hip extensors and keep the knee flexed enough so as not
to get hyperextended knees.
----------------------------------------------------------------------------
--------
Hey Ted,
Scott Orthotic Labs phone # is 1-800-821-5795.
Thought this might help.
----------------------------------------------------------------------------
--------
I have used with good success a couple of different knee brace styles offered
from Scott Orthotic Labs. They have one with polycentric knee joints that
incorporates the use of surgical tubing and midsection piece to give a
substantial extension assist that can be adjusted by the tension on the
tubing.
They also have a model that uses a drop lock knee joint, this one is nice
because they use ball keepers on the locks so they can be held above the
joint, and then put down when the person feels weakend or tired. With this
model you are able to release the tension on the knee joint from the tubing
so that the knee can rest at a 90 degree angle for sitting.
----------------------------------------------------------------------------
--------
Consider this;
A laminated ground reaction orthosis, be sure that the footplate is extremely
rigid and extended to the end of the toes. Double action ankle joints that
allow free plantar flexion but resist dorsiflexion. The Gentleman then can
work with you or a P.T. and be taught how to effectively use the orthosis.
The client must be instructed on holding his hip joint on the effected side
slightly forward during stance. He also needs to be trained to allow his
knee to fall into the pretib section of the orthosis, instead of forcefully
hyperextending his knee for stability. That is a waste of momentum in the
opposite direction.
The advantage is you are able to control the knee without the added hardware.
An energy efficient gait is possible without limiting flexion and extension
at the knee, or plantarflexion of the ankle. This also prevents disuse
atrophy of the quads due to locking the knee during ambulation.
I've have used this technique successfully for the last several years and on
my adult
clients I have mostly used a ground reaction orthosis fabricated by Oregon
Orthotic Systems.
Also, if you or the patient is not sure this will be effective try test
casting. Cast the client with fiberglass being sure that the foot and ankle
is at 90 degrees and positioned in neutral alignment, be sure the cast
extends to the end of his toes and is rigid around the ankle, ( but not so
rigid that you can't get the cast off when your finished ). Then put his
shoe on over the cast if possible, if not try a different shoe. Then have
him walk with the test cast in order to simulate the effect of an orthosis.
Make sure that the hip is positioned as mentioned and if it is adequate you
will see the knee stabilized.
----------------------------------------------------------------------------
--------
ted
locking the ankle at initial contact [ heel strike ] might/will increase the
probability of knee flexion . allow plantar flexion at i.t. & you decrease
the amtount of force at the knee
----------------------------------------------------------------------------
--------
Ted A. Trower C.P.O.
A-S-C Orthotics & Prosthetics
Jackson, Michigan, USA
<Email Address Redacted>
Citation
Ted A. Trower, “Responses - knee orthosis for femoral nerve palsy,” Digital Resource Foundation for Orthotics and Prosthetics, accessed November 26, 2024, https://library.drfop.org/items/show/212968.
