Questioning Conventional Wisdom.
Benveniste, David Mark
Description
Collection
Title:
Questioning Conventional Wisdom.
Creator:
Benveniste, David Mark
Date:
10/12/2005
Text:
Dear Colleagues,
Our primary concern for AK amputees and new amputees in particular, is to
prevent falls.
The major problems seem to be clearing the toe and getting sufficient
extension quickly enough to place the heel on the ground and prevent
buckling.
For a long time, I believe the standard practice in developed countries has
been the use of weight activated stance control knees for beginning AK pts,
less active pts, and for patients needing a greater degree of safety in
general.
Otto Bock's 3R49 has been the standard with other companies duplicating it
to varying degrees.
The 3R49 is a single axis knee and if the pt doesn't clear his toe and
stumbles, the pressure will activate the braking mechanism, IF it's within a
certain number of degrees of flexion.
Pts were encouraged to swing their leg and firmly plant their heel to gain
stability. So, the beginning pt needed to clear his toe and to make sure the
knee was in extension. In addition, the pt needed to unload the knee in
order to initiate flexion.
Instead of using the 3R49, I am now frequently using the Otto Bock 3R36. I
would also include any similar lightweight 4bar knees with strong extension
assists and a knee cap.
Short of active dorsiflexion, which I would like to see more of, the 4 bar
knee contributes to toe clearance and has inherent stability with its
posterior-superior instantaneous center of rotation. There is also no need
to unload the brake mechanism to gain flexion. (One of the reasons Otto Bock
created the 3R90/92)
In the Otto Bock 3R36 knee, there is a very strong extension assist which
assures rapid knee extension and therefore initial heel contact. With time,
and increased pt strength and control, you can reduce the strength of the
extension assist if desired.
Any flaws to this line of thinking? Anyone converted?
Mark Benveniste RN BS CP
MEDVA Medical Center
Houston, TX
USA
(There are other 4 bar knees similar in design to the 3R36 and 3R20
(stainless steel) but without the knee cap. Why manufacturers don't have
knee caps available on all knees is unclear to me.
BTW, DAW tells me you can request stronger spring assists for their knees.)
Our primary concern for AK amputees and new amputees in particular, is to
prevent falls.
The major problems seem to be clearing the toe and getting sufficient
extension quickly enough to place the heel on the ground and prevent
buckling.
For a long time, I believe the standard practice in developed countries has
been the use of weight activated stance control knees for beginning AK pts,
less active pts, and for patients needing a greater degree of safety in
general.
Otto Bock's 3R49 has been the standard with other companies duplicating it
to varying degrees.
The 3R49 is a single axis knee and if the pt doesn't clear his toe and
stumbles, the pressure will activate the braking mechanism, IF it's within a
certain number of degrees of flexion.
Pts were encouraged to swing their leg and firmly plant their heel to gain
stability. So, the beginning pt needed to clear his toe and to make sure the
knee was in extension. In addition, the pt needed to unload the knee in
order to initiate flexion.
Instead of using the 3R49, I am now frequently using the Otto Bock 3R36. I
would also include any similar lightweight 4bar knees with strong extension
assists and a knee cap.
Short of active dorsiflexion, which I would like to see more of, the 4 bar
knee contributes to toe clearance and has inherent stability with its
posterior-superior instantaneous center of rotation. There is also no need
to unload the brake mechanism to gain flexion. (One of the reasons Otto Bock
created the 3R90/92)
In the Otto Bock 3R36 knee, there is a very strong extension assist which
assures rapid knee extension and therefore initial heel contact. With time,
and increased pt strength and control, you can reduce the strength of the
extension assist if desired.
Any flaws to this line of thinking? Anyone converted?
Mark Benveniste RN BS CP
MEDVA Medical Center
Houston, TX
USA
(There are other 4 bar knees similar in design to the 3R36 and 3R20
(stainless steel) but without the knee cap. Why manufacturers don't have
knee caps available on all knees is unclear to me.
BTW, DAW tells me you can request stronger spring assists for their knees.)
Citation
Benveniste, David Mark, “Questioning Conventional Wisdom.,” Digital Resource Foundation for Orthotics and Prosthetics, accessed November 5, 2024, https://library.drfop.org/items/show/225624.
