Responses: B/L TF & energy costs

Responses: B/L TF & energy costs

Rick Milen

3/26/2007

EXCELLENT RESPONSE & INFO HEREIN.
  Original posting summary: Looking for energy costs for B/L TF ambulation. pt scenario: pt w/B/L TFAs who is insisting upon prostheses. She has been utilizing a motorized chair since January. She went ahead and got a prescription for B/L prostheses from her vascular surgeon. She is 75y/o with DX of CHF and a recent MI; not to mention the regular complications of DM plus left shoulder bursitis. I felt not a cadidate; wanted stats.
   
  Shared statistics w/pt. Recommended pt undergo extensive long term physical therapy to increase her conditioning and prove she is healthy enough to proceed. pt said Thank you for your honesty; if I can get legs, you're the man. Pretty cool lady.
  Informed cardiologist of my concerns and left it to him to Rx PT, etc. Pt saw her cardiologist & he corroborated my concerns... heart is too weak - doesn't think she'd even make it through a stress test - is not a candidate. She sounded resolved to that fact today.
  Thank you All,
  Rick Milen, CPO,PTA
  NEXSTEP, Inc. Pennsylvania
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  If you contact the ACA and talk with Paddy Rossbach - she might have
that info. She was very instrumental in a group called ASPIRE which did
energy studies. Let me know what you find out. (her response in in this email...)
[Dan Bastian, CP Progressive O&P]
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    I remember seeing a write up about it at the VA in Long Beach (Ed Ayyappa is the director there) (562)826-5678. If Ed does not have access, see if a person named Dana (male) is still working there...he may know. I believe the study was done by J. Perry at Rancho.
  Also, dont forget stubbies.
[DonniePriest]
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  The textbook of P&O by Lusardi and Nielsen has a good section on energy expenditure specific to persons with vascular and diabetic concerns (if I remember correctly). I always follow the general rule of 25% increased energy per joint that is lost but I'm aware of the significant increase even beyond this rule when both knees are lost. Bilat Tf has little study data but I do remember a few articles from school. If you need concrete data I can look and see if I still have them. You might also try a search on PubMed.
   
  This woman is most likely not a candidate. I have fit a few Bilat TF's and only one successfully moved to bilat prostheses with bending knees (c-legs), all of the others stayed with stubbies because of ease of use, reduced energy consumption, improved balance and increased gait speed. If you try anything, start her on stubbies. She will most likely not have the energy or balance to even ambulate successfully on those. All of my clients were relatively health men in their 40's and 30's, etiology trauma.
  [W. James Little, C.P.(c), B.Sc. Custom Prosthetic Services Ltd. Victoria, Canada]
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  Before we fit any bilateral transfemoral amputees, we insist that they
prove to their rehab team their cardiovascular stamina and endurance
using bilateral stubbies. Also the progression to learning to walk on
stubbies requires an upright posture and excellent balance reactions,
both of which would aid her in the quest to resume full length legs.
Make her some sockets with some height adjustable pylons with a
platform foot or feet and see what she can do. If she is exhausted on this
setup she will never master full length prosthesis. Improvement in her
cosmesis is one thing, with a set of full length prosthesis, but to
expect any functional use from them, she is biting off upwards of one
year of training/strengthening. I don't think the 'stats' will help you
convince her of your position. What you need for support of your
position, and which might help her would be matching her with a peer -
someone else who has become a successful user of both stubbies and
regular length prosthesis. Find someone who is younger and female.
[Linda McLaren BSR (PT) Clinical Resource Physiotherapist - Amputation
GF Strong Rehab Centre Vancouver, B.C. V5Z 2G9]
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  I would look in the 3rd Edition Atlas of Amputations and Limb
Prosthetics and I would look in the book Prosthetics and Orthotics, Lower Limb
and Spinal by Ron Seymour. Journal articles are good but the best
way to provide clinical evidence would be from a published book in my
meager opinion.
[Aaron Fitzsimmons, CP, OTR]
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The best article I have found on bilateral TFA energy expenditure was
in the Arch Phys Med Rehab Vol. 82, Feb 2001. Reported energy
expenditure was 240-300% more energy for ambulating and 466-707% more energy
than wheeling! Lots of different numbers depending on the source you
would use. Certainly from the history you relate she is not even close to
being a candidate for successful prosthetic fitting. She'll likely
have to find this out for herself though.
[Patrick Gross Physiotherapist HSC Winnipeg, MB, Canada]
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  The numbers for this type of data are pretty low. This is from a
chapter I helped write for the chapter Rehabilitation of People with Lower Limb
Amputation. In the newest (2006) edition of Physical Medicine & Rehabilitation
The references were pretty hard to pull together and some of the data that
referenced itself didn't always seem right but I think this summary is accurate.
  As you read it, remember that a 120% increase means that the person with bilateral transfemoral level amputations (I think it was n=1) used 220% of what non-amputee gait would be. I highly recommend looking up the originals if you can. Reference 86 is the
classic. I think it would be interesting to repeat this study with individual walking on well established components (any) that are more current rather than the SACH feet used then.
  I wonder if the differences would be the same or less.
  Energy expenditure
The effect of amputation on the energy cost of ambulation is
significant. Typically, the 'cost' of gait is measured in oxygen
consumption. Although various measurement techniques exist, usually the
volume of air inhaled and the amount of carbon dioxide exhaled is used to
calculate energy expenditure, and is subsequently scaled as a function of
body mass. The results can be reported as a function of distance or as a
rate. Oxygen rate, which is dependent on velocity, is often reported as
well. In addition to oxygen consumption and rate, maximal aerobic capacity
influences an individual's ability to perform with a prosthesis. This capacity decreases
  with both age and vascular involvement.84 Individuals with an amputation typically walk slower thannon-amputees in order to keep the oxygen consumption rate within a
tolerable aerobic range. If transtibial amputees walk with their speed reduced, they
incur a larger oxygen cost per distance than non-amputees walking at the same speed. Vascular amputees also have higher oxygen consumption per distance than traumatic amputees.84 When using oxygen consumption per unit distance measurements,
unilateral traumatic transtibial amputees use approximately 7% more energy to walk the same distance as non-amputees. This increases to 25% for traumatic transfemoral amputees. Vascular transtibial and transfemoral amputees use 25% and 87% more energy, respectively.83 Bilateral amputation increases the cost even further.85 A bilateral vascular transtibial amputee has a walking speed of 40 m/min at an oxygen cost 107% greater than
normal. This study had only a small number of subjects, but showed that a bilateral
traumatic transfemoral amputee walking at a reduced speed of 54 m/min had a reported oxygen cost that was 120% greater than normal.

83. Waters RL, Mulroy S. The energy expenditure of normal and pathologic gait.
        Gait Posture 1999; 9(3):207-231.
84. Waters RL, Perry J, Antonelli D, et al. Energy cost of walking of
     amputees: the influence of level of amputation. J Bone Joint Surg Am 1976; 58(1): 42-46.
85. Waters RL, Perry J, Chambers R. Energy expenditure of amputee gait.
     In: Moore W, Malone JM, eds. Lower limb amputation. Philadelphia: Saunders;
     1989:250-260.
   
  [ Laura Miller, PhD, CP Rehabilitation Institute of Chicago]
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  I don't know if there are any current studies. I do know there have been a few oxygen usage gait studies for amputees done in the past (I'm talking 20 - 30 plus years ago). I have often questioned the veracity of most P & O studies because of the small number of participants as well as the qualifications of the individuals conducting these studies. Call me a little skeptical but I have seen some of these P & O studies on both sides; I have impartially observed the study conducted in the lab, as well as being a practitioner reading the conclusions. Sometimes the conclusions are way off in my opinion.
       I have copies of most of the older gait studies (1940's through the 1980's) but unfortunately all of this literature is in storage at the present moment. I can't say that my memory is 100% accurate but I can give you some statistics that may be helpful in corroborating your opinion. Obviously this wouldn't help if you need the copies of the physical documentation in these journals, but access to a good med school library will provide you with that.
   
       Here is what I consider to be the most pertinent information. I believe this particular study was in the 1970's (maybe 1977) in the Archives of Physical Medicine and Rehabilitation and I think was conducted by an MD named Gonzales (not sure on spelling). Most of the studies were conducted on flat surfaces. Anyway here is what one of the more important ones found, and I believe this study was credible:
   
       1. An average length unilateral TT amputee used approximately 10% more oxygen in ambulating than a sound limb counterpart.
   
       2. An average length bilateral TT amputee used approximately 40% more oxygen ambulating than a sound limb counterpart.
   
       3. An average length TF used approximately 65% more oxygen than a sound limb counterpart
   
       4. There were no studies done for bilateral TF amputees or a TT and TF amputee. However other studies using crutches or a manual wheelchairs indicate that an average length TF uses only 55% more oxygen than their sound limb counterpart. This is a 10% net savings over the use of a prosthesis. This is not to say that a prosthesis is not imminently more practical and versatile in many ways, but there is definitely a greater energy consumption price tag for that additional freedom.
   
       You can do the math using deductive reasoning to extrapolate the results. If you figure that if a TT amputee quadruples the oxygen requirements from unilateral to bilateral, then the same minimum should hold true for TF amputees. I am not sure if the following is an accurate or precise analogy. The average TF uses 65% more oxygen ambulating on a level surface, and is therefore analogous to a person with two sound limbs climbing stairs.(When I think about it though, it sounds about right to me.)
   
       Multiply climbing stairs by four, and I think you get the approximate minimum demands placed on the heart for a bilateral TF amputee. For most individuals it is a cardiac arrest waiting to happen. If your patient has been in an electric wheelchair and was previously so ill that she required both legs being amputated; I would guess she is horribly out of shape with very little cardiovascular stamina or potential left whatsoever. This does not even begin to take into account her other serious physical limitations and impediments.
   
       My professional opinion. Just say no to her unrealistic expectations! On the surface it sounds rather harsh, but it is really a compassionate attempt to save this woman grief, disappointment, and heartache from further dashed hopes and dreams. If she continues to demand a chance, then she needs to be placed in a severe exercise regimen that will realistically prep her as a candidate for actual prosthetic use. I find that most individual's enthusiasm quickly wanes when confronted with this type of reasonable but difficult prerequisite.
   
       The exercise program becomes a legitimate litmus test to gauge the actual will power your patient is prepared to put forth. If she can faithfully execute a long-term cardiovascular exercise commitment, then possibly she can muster the resolve necessary to conquer two prostheses. It is my honest estimation however, that conquering Mount Everest would be a far lesser goal.
   
       I hope this provides some helpful insights and puts your situation into its proper perspective. By the way, over the years I have done several bilateral TF amputees (both young and old) from start to finish without one single long-term success story. Every single one has eventually opted for a wheelchair in the end as it is the path of least resistance. A wheelchair is eminently practical and provides a realistic and achievable energy expenditure on the part of the amputee. I know there are those rare Rudy Garcia-Tolson's out there, but they are one in a million shot in the dark to me.
  [Kim L. Ruhl CPO]
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    You are taking me back a while! My recollection is that the Net Energy Cost (ml O2/ Kg body wt/meter walked) of many amputees is 2 ½ times that of the non amputee, that in fact they require 2 ½ times the energy to walk at half the speed. When we did the study at the Hospital for Special Surgery in Manhattan , we didn’t even include any bilateral trans femoral amputees. I am sure their requirements would be off the scale! I am the first person to want people to have the opportunity to try and walk, however, putting someone on bilateral AK prostheses at that age with those health challenges……. Unless she is as strong as an ox and extremely coordinated just trying to manipulate the prostheses would surely put her at risk of falling and breaking her hips. If she were a single A/K I would tell her that she needs to be rehabilitated until she can get up from a chair and stand on one leg independently before she would be considered strong enough to manipulate a prosthesis –
 but you can’t do that here! I feel for her, she is obviously very motivated. Hope this is helpful – do let me know what the cardiologist says. Paddy
    Paddy Rossbach RN
  President & CEO
  Amputee Coalition of America
  www.amputee-coalition.org
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  I don't have any documentation to offer, but I distinctly remember the ABC
exam and the BS program in school supporting your opinion. CHF, recent MI
and DM are serious contraindications for prosthetic usage for a bilateral TF
patient. Heck, I'd even be concerned about a unilateral TF with that patient.
As far as energy expenditure, those numbers aren't exagerated. She's
looking at several times the effort in comparison to a non-amputee. I say stick to your gut instinct and don't take the risk. It's not worth it.
[Vincent Gest, CP Prosthetic & Orthotic Group, Inc.]
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    There were several studies performed in the late '60's and '70's, as well as some in the 90's. Check PubMed ( <URL Redacted>) and enter amputee, amputation, energy cost - See what comes up.
   
  I think this was particularly relevant:
                          Waters RL, Perry J, Antonelli D, Hislop H. - Energy cost of walking of amputees: The influence of level of amputation. J Bone Joint Surg Am. 1076 Jan;58(1):42-6. PMID: 1249111 [PubMed - indexed for MEDLINE] Carol A. Sheredos, PT, MA
Scientific Program Specialist
National Center for Medical Rehabilitation Research (NCMRR)
National Institute for Child Health and Human Development (NICHD)/ National Institutes of Health (NIH)
6100 Executive Blvd. - Rm 2A03 - MSC 7510
Bethesda, MD 21092-7510
301-402-2242 or 410-302-4926
NCMRR: <URL Redacted>
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  There is a short summary in the Atlas of Limb Prothetics, chapter 32:
Energy Expenditure of Walking. In there they reference the original
research and summarize it.

I would think you would not be paid by medicare if you fit this patient
and you would be held liable if she did suffer cardiac insult while
using the prostheses.

Personally I do not enjoy giving that kind of news to patients and wish
the physicians in these cases would educate themselves and find their
spines. Of all people a vascular surgeon should know this is
unrealistic.
[David Loney CP WillowBrook P&O Lebanon ,NH]
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