RESULTS: Re: [OANDP-L] AFO with drop locks

RESULTS: Re: [OANDP-L] AFO with drop locks

eric chen

5/9/2009

Here's the original question followed by the responses that I received:

ORIGINAL:
I've recently encountered a prescription for a gentleman for an AFO with
drop lock ankle joints to immobilize the ankle except for driving, where he
wants to allow plantarflexion. Drop locks are not completely necessary, so
long as there's an optional lock. I have a couple designs in mind, but am
curious to hear of anyone's attempts/suggestions on such a device
(materials, design, joints, etc.).

RESPONSES:
Is this bilateral? If not, isn't just easier to give the guy an SAO and
tell him to use his other leg to operate the pedals? If you really need to
go with bulky drop locks, which I have never had the need to do in 30 years
on an ankle, I would just go with a single lateral drop lock, c-size becker
and a simple lap joint on the medial side maybe from an upper extremity
selection.
=============================
We have an ankle joint that may fit your need. It is called the Dyna-Lock ankle joint. When
it is not engaged it allows free plantar and dorsi flexion. Once you
engage the joint, it ratchets into progressive dorsi flexion and blocks
plantar flexion. You can veiw it at our web site www.scottorthotic.com.
We usually use the joint on the lateral side, and can use a
combination of other types of joint on the medial. To lock the patient
into a desired angle you could use our Meridian ankle joint on the
medial side, and block how much dorsiflexion you want.
This joint is also terrific in managing severe plantar flexion contractures.
=============================
Need to check your state laws regarding driving with a orthosis or a
prosthesis. Some states do not allow this.
=============================
put him into trigger release. OTS, Fillauer has those.=============================
I have done this before and used drop lock knee joints.
The upright was about 2 inches long proximal to the joint and a little
less distally. I mounted them on the cast as I mount a regular ankle
joint. The concern I have with my design is that I don't think it is
appropriate for people much over 160-170 pounds. If I ever make one for
someone heavier I plan to get a stirrup blank and grind it to fit
the knee joint attachment. I will then fab it like a metal AFO with a
plastic footplate. Good luck and I am interested to hear the responses
you get.
=============================
I would provide an afo with a posterior button stop of 90 degrees, and
provide a split 2 velcro posterior strap attached to the back of the
foot plate, split the strap so you can attache it 15 mm behing the
ankle axis on the heel. Loop the strap over the top return loop
perferable one that is solid like an upper extremity return buckel that is solid. This way when he is out of the car he can lock the dorsi resist strap up.
If you patient is too fat to bend over to do this I don't have another
suggestion. In any design if the patients wt. is above safty of the
design beware.
=============================
ToeOFF will stabilize the ankle and still allow driving in most cases...
=============================
I have a patient with a
similar situation. He wanted an AFO which had a disengageable plantar
flexion stop. I told them there was no such animal. He was undetered
and declared that he had a friend who was a machinist and could make
anything that we could design, so I met with the two of them and he
came up with a prototype, which went through a revision and then I
encorporated this into a pair of AFOs. It was somewhat bulky, but it
worked. I worked somewhat like a rifle bolt. When engaged it acted
like a plantar flexion stop, but when the patient sat down at his desk,
or for driving, he could reach down and disengage the stop which would
allow him to plantarflex.
=============================

Thanks everyone,


Eric Chen, CO



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