Knee Hyperext.replies Part 2

Knee Hyperext.replies Part 2

Shane Jansen

7/18/2001

First of all, take care of the moment arm forcing the knee back, which is the
plantarflexed ankle, with an AFO to keep the ankle at 90 or slightly
dorsiflexed. If the ankle doesn't get to 90 use a heel wedge to achieve
90. An
external lateral heel post on the AFO will help control the lateral thrust
of the
knee as well. If this does not stop the HE and they go back on their heel you
will probably need to go to a KAFO with a free knee with the knee set in a
slight
dorsiflexion. Good luck!
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shane
i know that flex tech makes a KO that is designed for HE. I have not used the
device, but looks pretty good.
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Otto Bock used to make 22mm offset knee joints. The joint provides stance
stability because of the offset. Be sure the design won't cause a fracture
of the femur if violently flexed. I generally used an anterior thigh
section with straps in the posterior for attachment and security with
crossing straps to control hyperextension. I prefer to attach to a foot
plate in the shoe with free motion ankle. This tends to keep the orthosis
in place at all times and not allow it to deposition itself from gravity or
rotation.
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This isn't exactly on point, since you are asking about an extension-stopping
knee orthosis, but I have found generally that the forces generated by any KO
successfully stopping hyperextension are too great for these patients to
bear.

I have been much more successful using a ground-reaction AFO, or, if more
control is needed, a short KAFO. But usually the ground-reaction AFO will do
the trick. It must be accompanied by some gait training, as these patients
have developed back habits of relying on their hamstrings for stability. They
will have to learn to allow the ground-reaction forces to keep them stable.
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Sounds as if you need to go w/ a double-upright KAFO to stop the
hyperextension. My cutoff for trying to control HE with an AFO is 7degrees
HE. I usually make a molded plastic KAFO, double-upright w/ SS free knee
joints and sometimes add an adjustable b
ackstrap. It works and the patient is comfortable. Bill, C.P.
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I wrote an article a few years ago on a Hyperextension Sling that I have used
for knee's for years, find it under my name in the O&P literature.

Robert A. Bangham, C.O., L.O.
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I use an AFO for control of hyperextension for many of the diagnoses you
list. The hyperextension is caused by week knee extensors and is a
compensatory response to prevent falling. Taking away the hyperextension
without adding stabilization of the knee from buckling will not help the
patient, and may cause unwanted falls. Slight hyperextension can aid in
stability without creating any problem, long term
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I use the functional ACL type KO's for my patients as well. I have tried
the Swedish Knee cages from Alimed and other similar KO's from other
distributors with little success. If you find a perfect HEKO please let me
know.
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An old time brace-man showed me the design of a KAFO with an anterior
thigh cuff. It is a wide anterior cuff that pivots. It actually works
quite well. I can draw a picture and fax if necessary. I also am seeing
one wearer in the next couple of weeks. Let me know if you want some
pictures.
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ORIGINAL POST

Dear List Members
Lately I have seen a number of patients with hyperextension of the knee
during gait. The HE has usually resulted from one of the following
conditions: CVA, TBI(tramatic brain injury) and incomplete spinal injury.
Most of these people do not have an associated footdrop or loss of D/F range.

Some are up to 15 Deg. of HE and do so with a great deal of force. Some of
these people are able to control thier HE if they concentrate and walk
slowly and are working on this with thier Physiotherapists(this control
usually goes out the window when they are in a hurry or not completely
focused - hence the need for an orthosis)

I have used a range of orthoses, determined usually by the amount of force
involved and how active the person is.

I have found the C.H.E.C.K by Camp particularly useful but it will break
if used by the forceful, active hyperextender!

This is my question:
What are you fitting for the active forceful hyperextenders? (OTS and Custom)

To date I have used Functional ACL type KO's with usually 10-20 deg. ext.
stops installed. These work reasonably well but do not always fully limit
HE and of course are not designed primarally for this task. There knee
joints will deteriorate relatively quickly I'm sure.

I look forward to your responses and will post a summary to the whole list.

Shane Jansen
Orthotist
Whangarei
New Zealand