Variable cadence RESPONSES (PART1)
Stephan Manucharian
Description
Collection
Title:
Variable cadence RESPONSES (PART1)
Creator:
Stephan Manucharian
Date:
1/11/2015
Text:
Dear List!
Here are the responses to the following question:
1. Medicare K2 level classification mentions ability to transverse *low-level
environmental barriers (EB), such as curbs, stairs and uneven surfaces*,
whereas the K3 level classification requires ability to transverse *most
environmental barriers* QUESTION: In your opinion, what other EBs (besides
curbs, stairs and uneven surfaces) one may expect from a K3 ambulator to be
able to negotiate?
2. Normal cadence of an able-bodied person is considered to be between 100
and 115 steps/min. Do you expect a K3 ambulator to fit in the same range?
Regardless of the level of amputation?
3. In order to determine one's ability to ambulate with variable cadence,
how variable should his/her gait speed be? Is a mere 5 steps/min (or 5%
increase) sufficient? Or maybe 10%? Where do you draw a line?
RESPONSES:
#1 - I have no idea so we always rely on the patient meeting all K2
criteria PLUS variable cadence as the key.
#2 - We have never concerned ourselves with matching normal AB speeds,
rather having the patient maximize their new potential. I can see value in
knowing this, but we don't currently apply it.
#3 - I have never heard a threshold or landmark placed on what we are
looking for in variable cadence so this has always been pretty subjective.
Low level barriers in other rehab settings are 4 or less, with or with out
a required assistive device. Generally not traversing or having difficulty
with steep inclines or declines (Non-ADA ramps), Foot over foot stair
descent, stepping over larger obstacles. Typical of Unrestricted Community
Ambulation.
The general health ability to ambulate at a certain speeds is used in the
evaluation by Therapist on other impairments. Mostly utilizing m/s Meters
per Second. In the attached paper Lusardi shows that at .8m/s the patient
is Unrestricted. Under .8m/s patient is Limited.
Gailey's Amputee Mobility Predictor NoPro utilizes task from many Outcomes,
part of which looks at speed and balance to find the amputee's general
potential ability.
To answer your questions, though, specifically, I see this more as a
philosophy instead of an actual list of items. If going from any point, A
to B, would the person be willing and able to go there, without knowing
what is in-between. However, if the person would have to design a path
from A to B to find the path of least resistance, and/or avoid certain
things, then this person should be further evaluated to be a lower
functional level. A K-3 level ambulatory should be able to walk on snow
and icy conditions, although should take smaller steps not to have his or
her heel slide out because the ankle cannot move, and thus, one of the
limitations of a K-3 level foot as compared to a K-2 or K-1 level foot
(single axis foot characteristics). Many people live in areas where it
snows. A K-3 level ambulatory should be able to easily walk up and down a
hill, where the extra strength in the quads are used, where a K-2 likely
does not have the same strength to do the same, and thus needs less energy
return and more movement in the ankle to compensate for this.
You do bring up a valid point that the requirements for an AK are likely
different than a BK, as the energy expenditure for each level is greatly
different. However, the AK should be able to use the benefit of the
differential swing phases and able to overcome the extra weight when
compared to the lower functional level. However, a functional level 3 BK
ambulatory likely would walk faster and do better than a functional level 3
AK ambulatory when comparing them to the same tasks. Perry did energy
studies years ago, and I am sure there are others who have done similar.
Off the top of my head, a EB I could think of would be a ladder, tree stand
for hunting, floating dock system for a fisherman. Other EB will be either
job related or hobby related and would need to be asked from the actual
patient. I guess for your study, you could ask anyone what EB do they
encounter on a daily bases. Just last week, I had to navigate my living
room of thousands of pieces of Lego's and other toys from the kids opening
their X-Mas gifts. If that’s not an environmental barrier, I don’t know
what is.
In regards to #2 & #3 its tricky. In my opinion cadence/speed does not
matter with the capability of transversing low-level EB vs ability to
transverse most EB One can either take their time transversing stairs as
or take them really quick. I once worked with a guy that wore a TF
prosthetic device and a KAFO. At the hospital we worked at, he would slide
down the hand rails in the stairwell to get down to the next floor. He was
faster than me since I actually place my feet on the ground step over step.
I do remember when I was back in prosthetic school, right after the wheel
was invented, the argument of variable cadence was demonstrated very
clearly.
First stand in one place, then walk across the floor at your normal rate of
speed. Now when you have reached the other side of the room, turn around
and walk back VERY slowly to your original start position. There! You have
demonstrated you can walk with a variable cadence. Every thinks of this as
increasing your speed, but if you slow down you have also varied your
cadence.
In relationship to hydraulic knees, the property of the fluid will take in
account normal walking speed vs walking VERY slowly. Also the hydraulic
fluid will flow quicker if you have to run across the street if you are
facing being hit by a bus. But during all 3 walking speeds, the hydraulic
should perform within its operational range and provide the user the stance
control the hydraulic knee was designed to do.
Now to clarify, I am not putting patients into K3 equipment because they
can walk slower to demonstrate variable cadence. I believe endurance,
strength and overall personal performance should be a better indicator to
put patients into the higher activity prosthetic equipment.
If I was studying how to update the K Level for prosthetics, first I
would look at the Medicare LCD's for lower limb prosthetics. Medicare has
specific policy on how a patient should be treated. First and for most,
the equipment that we provide amputees should match appropriate treatment
plans for amputation. Medicare policy also states that the equipment
should be the most cost effective management for amputation. Agree or
disagree with this approach, this is the current policy that we have to
provide services. SO the burden of medical justification for various knees
and feet is placed on the prosthetist. Most ordering physicians do not
know the differences between all the L-Code we put in front of them to
review and sign off on when we give them a detail RX.
If K-levels could be tied to a standardize assessment of (endurance,
strength and overall personal performance) either from an outside source,
like a therapist or maybe a physiatrists this would provide a better
clarification of the patient functional level and maybe there would be less
grey area which prompt your original question of what is the difference
between transverse low EB vs ability to transverse most EB because the
current K-level system is antiquated.
I think that a K2 ambulator is not capable of dodging a collision in a
crowd where the K3 ambulator can side step and avoid the bump and potential
fall. This may not be considered a barrier but it is the subjective vision
I use to determine K level.
I do not expect all K3 ambulators to be able to walk at normal cadence. I
would hope that they could match or exceed their walking speed prior to the
amputation.
Because we are dealing with a bureaucracy that knows nothing about patient
care, variable cadence should be described as any change in walking speed.
As far as EBs for K3s vs. K2s the only really apparent thing would be ramps
and hills. maybe stair of varying heights and depths or the ability to
acend step over step althought the verbiage in the defininition does not
allow for that. ramps would be the big one.
As far as the actual cadence number is concerned there should be a
threshold value for K3s although again the verbiage does not allow for
that. I would expect a K3 to achieve the 115 to 120 as an unlimited
community ambulator just intuitively although I personally think gait
speed/velocity is more important for a threshold. For the difference to
determine variable cadence you would think a 5-8% MDC like that which has
determined for gait speed would suffice. I couldn't find an MDC or MDIC
for cadence out there (not to say there isn't one somewhere), so
establishing a realistic value for that would be very beneficial.
PART 2 to follow
*Dr. Stephan R. Manucharian, CP, BOCO, LP(NJ), FAAOP*
*Doctor of Health ScienceClinical DirectorOrthopedic Arts Laboratory,
Inc.141 Atlantic Ave., Brooklyn, NY 11201718-858-2400; Fax:
718-858-9258; <URL Redacted>
< <URL Redacted>>The content of this communication is for
exclusive use of the addressee and may contain confidential, privileged and
non-disclosable information. If the recipient of this communication is not
the addressee, such recipient is strictly prohibited from printing,
photocopying, saving on any media, distributing or otherwise using the
information contained herein. If you received this communication in error,
please contact the sender by e-mail, fax or telephone and destroy this
document.*
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To unsubscribe, send a message to: <Email Address Redacted> with
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If you have a problem unsubscribing,or have other
questions, send e-mail to the moderator
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OANDP-L is a forum for the discussion of topics
related to Orthotics and Prosthetics.
Public commercial postings are forbidden. Responses to inquiries
should not be sent to the entire oandp-l list. Professional credentials
or affiliations should be used in all communications.
Here are the responses to the following question:
1. Medicare K2 level classification mentions ability to transverse *low-level
environmental barriers (EB), such as curbs, stairs and uneven surfaces*,
whereas the K3 level classification requires ability to transverse *most
environmental barriers* QUESTION: In your opinion, what other EBs (besides
curbs, stairs and uneven surfaces) one may expect from a K3 ambulator to be
able to negotiate?
2. Normal cadence of an able-bodied person is considered to be between 100
and 115 steps/min. Do you expect a K3 ambulator to fit in the same range?
Regardless of the level of amputation?
3. In order to determine one's ability to ambulate with variable cadence,
how variable should his/her gait speed be? Is a mere 5 steps/min (or 5%
increase) sufficient? Or maybe 10%? Where do you draw a line?
RESPONSES:
#1 - I have no idea so we always rely on the patient meeting all K2
criteria PLUS variable cadence as the key.
#2 - We have never concerned ourselves with matching normal AB speeds,
rather having the patient maximize their new potential. I can see value in
knowing this, but we don't currently apply it.
#3 - I have never heard a threshold or landmark placed on what we are
looking for in variable cadence so this has always been pretty subjective.
Low level barriers in other rehab settings are 4 or less, with or with out
a required assistive device. Generally not traversing or having difficulty
with steep inclines or declines (Non-ADA ramps), Foot over foot stair
descent, stepping over larger obstacles. Typical of Unrestricted Community
Ambulation.
The general health ability to ambulate at a certain speeds is used in the
evaluation by Therapist on other impairments. Mostly utilizing m/s Meters
per Second. In the attached paper Lusardi shows that at .8m/s the patient
is Unrestricted. Under .8m/s patient is Limited.
Gailey's Amputee Mobility Predictor NoPro utilizes task from many Outcomes,
part of which looks at speed and balance to find the amputee's general
potential ability.
To answer your questions, though, specifically, I see this more as a
philosophy instead of an actual list of items. If going from any point, A
to B, would the person be willing and able to go there, without knowing
what is in-between. However, if the person would have to design a path
from A to B to find the path of least resistance, and/or avoid certain
things, then this person should be further evaluated to be a lower
functional level. A K-3 level ambulatory should be able to walk on snow
and icy conditions, although should take smaller steps not to have his or
her heel slide out because the ankle cannot move, and thus, one of the
limitations of a K-3 level foot as compared to a K-2 or K-1 level foot
(single axis foot characteristics). Many people live in areas where it
snows. A K-3 level ambulatory should be able to easily walk up and down a
hill, where the extra strength in the quads are used, where a K-2 likely
does not have the same strength to do the same, and thus needs less energy
return and more movement in the ankle to compensate for this.
You do bring up a valid point that the requirements for an AK are likely
different than a BK, as the energy expenditure for each level is greatly
different. However, the AK should be able to use the benefit of the
differential swing phases and able to overcome the extra weight when
compared to the lower functional level. However, a functional level 3 BK
ambulatory likely would walk faster and do better than a functional level 3
AK ambulatory when comparing them to the same tasks. Perry did energy
studies years ago, and I am sure there are others who have done similar.
Off the top of my head, a EB I could think of would be a ladder, tree stand
for hunting, floating dock system for a fisherman. Other EB will be either
job related or hobby related and would need to be asked from the actual
patient. I guess for your study, you could ask anyone what EB do they
encounter on a daily bases. Just last week, I had to navigate my living
room of thousands of pieces of Lego's and other toys from the kids opening
their X-Mas gifts. If that’s not an environmental barrier, I don’t know
what is.
In regards to #2 & #3 its tricky. In my opinion cadence/speed does not
matter with the capability of transversing low-level EB vs ability to
transverse most EB One can either take their time transversing stairs as
or take them really quick. I once worked with a guy that wore a TF
prosthetic device and a KAFO. At the hospital we worked at, he would slide
down the hand rails in the stairwell to get down to the next floor. He was
faster than me since I actually place my feet on the ground step over step.
I do remember when I was back in prosthetic school, right after the wheel
was invented, the argument of variable cadence was demonstrated very
clearly.
First stand in one place, then walk across the floor at your normal rate of
speed. Now when you have reached the other side of the room, turn around
and walk back VERY slowly to your original start position. There! You have
demonstrated you can walk with a variable cadence. Every thinks of this as
increasing your speed, but if you slow down you have also varied your
cadence.
In relationship to hydraulic knees, the property of the fluid will take in
account normal walking speed vs walking VERY slowly. Also the hydraulic
fluid will flow quicker if you have to run across the street if you are
facing being hit by a bus. But during all 3 walking speeds, the hydraulic
should perform within its operational range and provide the user the stance
control the hydraulic knee was designed to do.
Now to clarify, I am not putting patients into K3 equipment because they
can walk slower to demonstrate variable cadence. I believe endurance,
strength and overall personal performance should be a better indicator to
put patients into the higher activity prosthetic equipment.
If I was studying how to update the K Level for prosthetics, first I
would look at the Medicare LCD's for lower limb prosthetics. Medicare has
specific policy on how a patient should be treated. First and for most,
the equipment that we provide amputees should match appropriate treatment
plans for amputation. Medicare policy also states that the equipment
should be the most cost effective management for amputation. Agree or
disagree with this approach, this is the current policy that we have to
provide services. SO the burden of medical justification for various knees
and feet is placed on the prosthetist. Most ordering physicians do not
know the differences between all the L-Code we put in front of them to
review and sign off on when we give them a detail RX.
If K-levels could be tied to a standardize assessment of (endurance,
strength and overall personal performance) either from an outside source,
like a therapist or maybe a physiatrists this would provide a better
clarification of the patient functional level and maybe there would be less
grey area which prompt your original question of what is the difference
between transverse low EB vs ability to transverse most EB because the
current K-level system is antiquated.
I think that a K2 ambulator is not capable of dodging a collision in a
crowd where the K3 ambulator can side step and avoid the bump and potential
fall. This may not be considered a barrier but it is the subjective vision
I use to determine K level.
I do not expect all K3 ambulators to be able to walk at normal cadence. I
would hope that they could match or exceed their walking speed prior to the
amputation.
Because we are dealing with a bureaucracy that knows nothing about patient
care, variable cadence should be described as any change in walking speed.
As far as EBs for K3s vs. K2s the only really apparent thing would be ramps
and hills. maybe stair of varying heights and depths or the ability to
acend step over step althought the verbiage in the defininition does not
allow for that. ramps would be the big one.
As far as the actual cadence number is concerned there should be a
threshold value for K3s although again the verbiage does not allow for
that. I would expect a K3 to achieve the 115 to 120 as an unlimited
community ambulator just intuitively although I personally think gait
speed/velocity is more important for a threshold. For the difference to
determine variable cadence you would think a 5-8% MDC like that which has
determined for gait speed would suffice. I couldn't find an MDC or MDIC
for cadence out there (not to say there isn't one somewhere), so
establishing a realistic value for that would be very beneficial.
PART 2 to follow
*Dr. Stephan R. Manucharian, CP, BOCO, LP(NJ), FAAOP*
*Doctor of Health ScienceClinical DirectorOrthopedic Arts Laboratory,
Inc.141 Atlantic Ave., Brooklyn, NY 11201718-858-2400; Fax:
718-858-9258; <URL Redacted>
< <URL Redacted>>The content of this communication is for
exclusive use of the addressee and may contain confidential, privileged and
non-disclosable information. If the recipient of this communication is not
the addressee, such recipient is strictly prohibited from printing,
photocopying, saving on any media, distributing or otherwise using the
information contained herein. If you received this communication in error,
please contact the sender by e-mail, fax or telephone and destroy this
document.*
********************
To unsubscribe, send a message to: <Email Address Redacted> with
the words UNSUB OANDP-L in the body of the
message.
If you have a problem unsubscribing,or have other
questions, send e-mail to the moderator
Paul E. Prusakowski,CPO at <Email Address Redacted>
OANDP-L is a forum for the discussion of topics
related to Orthotics and Prosthetics.
Public commercial postings are forbidden. Responses to inquiries
should not be sent to the entire oandp-l list. Professional credentials
or affiliations should be used in all communications.
Citation
Stephan Manucharian, “Variable cadence RESPONSES (PART1),” Digital Resource Foundation for Orthotics and Prosthetics, accessed November 23, 2024, https://library.drfop.org/items/show/237057.
