Functional Considerations for Prosthetic Candidacy
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Transcript of Functional Considerations for Prosthetic Candidacy
Lisa U. Pascual, MD
Assistant Clinical Professor
Department of Orthopaedic Surgery
University of California, San Francisco
Functional Considerations for
Prosthetic Candidacy
“Will My Patient Be Able to Walk?” (And What Should I tell Her to Expect?)
What do I Tell My Patient?
65 yo M, now s/p R AKA
DM, HTN, ESRD, CAD, h/o mi, h/o previous BKA on same side
Wheelchair bound for short distances on level surfaces
Transfers with assist
Limited ambulation prior to recent surgery as had difficulty with ulcer to RLE
Objectives
To be able to understand the impact of:
Premorbid Medical Concerns – Comorbidities
– Age
– Psychosocial Concerns
Premorbid Functional Status – Gait
– Energy Expenditure
The Interdisciplinary Team
“When am I getting a prosthesis?”
Assumes “when,” not “if.”
Is the patient a prosthetic candidate?
Prosthetic Candidacy: Premorbid Medical Concerns
Comorbidities
Age
Psychosocial Status
Prosthetic Candidacy: Premorbid Medical Concerns
Comorbidities:
Ischemic Heart Disease, or
Hemiplegia, or
Bronchitis, or
Bilateral amputation
performed worse than amputees without these diseases in the Walking Ability Index
Siriwardena, et al 1991
Prosthetic Candidacy: Premorbid Medical Concerns
Comorbidities:
Severe Cardiopulmonary Disease – May be a major consideration for withholding prosthetic
use given the energy expenditure required for ambulation
Compromise of the Contralateral Foot – Relative contraindication
Prosthetic Candidacy: Premorbid Medical Concerns
Comorbidities:
Dialysis – Previously shown to perform worse
– Similar outcomes for dysvascular amputees with ESRD compared to those without
Czyrny, et al. 1994
Prosthetic Candidacy: Premorbid Medical Concerns
Comorbidities:
Obesity – BMI did not correlate with functional outcome in a
dysvascular amputee
– Obesity did not predict a poorer prognosis Kalbaugh, et al. 2006
– However, obesity may have an impact on musculoskeletal pain
Prosthetic Candidacy: Premorbid Medical Concerns
Comorbidities:
Compliance is a significant criteria for successful prosthetic use
Muellar, et al. 1985
Prosthetic Candidacy: Premorbid Medical Concerns
Age: Fit Trends Throughout the Years 1959: 55.3% were fit with prostheses, only 2-3% were older
Chapman, et al. 1959
1986: Increased age associated unfavorably with social dependence and physical ability
Helm, et al. 1986
1991: 87% (N=26) were fit with prostheses Harris, et al. 1991
1993: 1846, 80% fit with prostheses (majority elderly) Stewart, et al. 1993
Prosthetic Candidacy: Premorbid Medical Concerns
Age: Fit Trends Throughout the Years
Poorer outcomes vs. successful rehabilitation
– 25 yrs + ago, more AKAs in older dysvascular patient to ensure healing: higher energy demands
– More recently, less AKAs, more BKAs
Prosthetic Candidacy: Premorbid Medical Concerns
Age
Schoppen et al, 2003
• >60 year oldlower level of function after 1 year
• Most predictive: 2 weeks post amputation:
• Age
• 1 leg balance on unaffected limb
• Cognitive impairment
Prosthetic Candidacy: Premorbid Medical Concerns
Age
• Fletcher et al, 2001
• Wanted to determine the rate of successful prosthetic fit in
geriatric amputees and determine predictors
• Success rates vary for fit of elderly:
• “selected group” for fit
• “unselected” group for fit
• Selected individuals can be successfully fit
• Factors that adversely affected fit: increased age,
cerebrovascular disease, dementia, AKA
Prosthetic Candidacy: Premorbid Medical Concerns
Age
Age alone is not a contraindication for prosthetic use, careful consideration of other factors is needed
Prosthetic Candidacy: Premorbid Medical Concerns
Psychosocial Concerns
Varied results/different populations: – Return to home varied 20-80%
– Decrease in need for help at home post amputation
– Improved health as less pain post amputation
– Decrease in quality of life the higher the amputation
Prosthetic Candidacy: Premorbid Medical Concerns
Psychosocial Concerns
Limited or lack of studies on: – Quality of Life
– Social network and other environment factors
• Although re-operation and social dependency appears to
negatively affect outcome
Prosthetic Candidacy: Premorbid Medical Concerns
Morbidity and Mortality: Dysvascular Amputees
15-20% risk of losing contralateral limb 2 years post amputation
– Risk increases to 40% at 4 years
5 year survival for lower limb dysvascular amputees averages 30-40% overall
Patients with diabetes vs. peripheral vascular disease:
– Shorter survival
– Related to level of amputation
Survival: BKA > AKA (presumably due to more widespread involvement)
Prosthetic Candidacy: Premorbid Medical Concerns
In summary:
Adequate data still not available to:
– Reliably identify all predictors of outcome
– Look at predictive factors when series include combinations of amputations due to trauma with dysvascular causes (pooled populations)
– Look at “unselected” populations
Prosthetic Candidacy: Premorbid Functional Status
Was the patient ambulating prior to surgery?
Was the patient transferring on own prior to surgery?
What type of amputation is being considered?
What are the energy expenditure factors that need to be considered?
Prosthetic Candidacy: Gait
Prosthetic Candidacy: Gait
Documented kinematics
of gait
Prosthetic Candidacy: Gait
Prosthetic Candidacy: Energy Expenditure
•Normal Gait: 3 METs
•Waters, Perry, et al. 1976
Energy Cost of Ambulation
Increase (%) MET
No prosthesis, with crutches 50 4.5
Unilateral BK with prosthesis 9-28 3.3-3.8
Unilateral AK with prosthesis 40-65 4.2-5.8
Bilateral BK with prosthesis 41-100 4.2-6.0
BK plus AK with prosthesis 75 5.3
Bilateral AK with prosthesis 280 11.4
Unilateral hip disarticulation with prosthesis 82 5.5
Hemipelvectomy with prosthesis 125 6.75
Prosthetic Candidacy: Energy Expenditure
Normal Ambulation: 3 METS DeLisa, PM&R Principles and Practice.
Correlation of Energy Cost of Ambulation According to Level of Amputation with
Estimated Work Capacity According to Cardiac Functional Class
Cardiac Class MET Amputee Ambulation MET
Class IV <2 --- ---
Class III <2 to <5 Wheelchair 2.0-3.0
Unilateral BK with prosthesis 3.3-3.8
Class II >5 to <7 No prosthesis with crutches 4.5
Unilateral AK with prosthesis 4.2-5.0
Bilateral AK with prosthesis 4.2-6.0
BK plus AK with prosthesis 5.3
Hip disarticulation with
prosthesis
5.5
Hemipelvectomy with
prosthesis
6.75
Class I >7 Bilateral AK with prosthesis 11.4
Prosthetic Candidacy: Premorbid Functional Status
Schoppen et al, 2003.
Unilateral leg stance significant predictor of functional outcome
Memory most important mental predictor for function
Prosthetic Candidacy: Premorbid Functional Status
Possible factors:
Strong motivation to walk
Level of physical fitness as measured by maximal oxygen consumption after amputation
Prosthetic Candidacy: Premorbid Functional Status
Functional Independence Measure (FIM) as a predictor of functional outcome:
Muecke et al,1992: – FIM scores a poor predictor
– FIM scores in lower level amputees had potential for greater change in score
Leung et al, 1996: – FIM not useful as a predictor of outcome
– Only motor subscore at discharge correlated with use of a prosthesis
Prosthetic Candidacy: Premorbid Functional Status
Gailey et al, 2002. – Amputee Mobility Predictor: designed to measure an
amputee’s functional capacities and predict ability to ambulate with a prosthesis
– Can be performed with or without a prosthesis
– Looks at sitting, transfers, sit to stand, standing balance, gait activities
– Can be performed with and without a prosthesis
– Can assist in assigning an Medicare Functional Classification Level (MFCL)
Managing Expectations
“What kind of prosthesis am I going to get?”
Dependent of pre-morbid level of functioning
The prosthesis that is on TV may not be the appropriate one for them
Managing Expectations
Goal of Prosthetic Prescription:
To provide the amputee with the ability to return to participating in activities that are important to them in society
To provide a prosthesis that is appropriate for their level of activity, ability and weight
Managing Expectations
Energy Storing Feet: Highly subjective satisfaction rates Limited biomechanical evidence of significant benefit Trends suggest increased walking speed, greater
stride length, slight decrease in metabolic expenditure at high speeds – no superiority for level walking
Managing Expectations
K Levels
K0 Does not have the ability or potential to ambulate or transfer safely with or without assistance and a prosthesis does not enhance the quality of life or mobility.
K1 Has the ability or potential to use a prosthesis for transfers or ambulation on levels surfaces at fixed cadence. Typical of the limited and unlimited household ambulator.
K2 Has the ability or potential for ambulation with the ability to traverse low level environmental barriers such as curbs, stairs, or uneven surfaces. Typical of the limited community ambulator.
K3 Has the ability or potential for ambulation with variable cadence. Typical of the community ambulator who has the ability to traverse most environmental barriers and may have vocational, therapeutic, or exercise activity that demands prosthetic use beyond simple locomotion.
K4 Has the ability or potential for prosthetic ambulation that exceeds basic ambulation skill, exhibiting high impact, stress, or energy levels. Typical of the prosthetic demands of the child, active adult, or athlete.
Managing Expectations
Microprocessor knees:
Controls postural stability
Varies step cadence
Enhances ability to walk on uneven surfaces
Managing Expectations
K Level Description Medicare-Covered Prosthesis
K0 Nonambulatory None
K1 Household ambulator Constant-friction knee
K2 Limited community ambulator Constant-friction knee
K3 Unlimited community ambulator Fluid-control knee
K4 Very active Fluid-control knee
Source: Region B Medicare Supplier Bulletin
Source: Region B Medicare Supplier Bulletin
K Level Description Medicare-Covered Prosthesis
K0 Nonambulatory None
K1 Household ambulator Constant-friction knee
K2 Limited community ambulator Constant-friction knee
K3 Unlimited community ambulator Fluid-control knee
K4 Very active Fluid-control knee
Source: Region B Medicare Supplier Bulletin
What do I Tell My Patient?
65 yo M, now s/p R AKA
DM, HTN, ESRD, CAD, h/o mi, h/o previous BKA on same side
Wheelchair bound for short distances on level surfaces
Transfers with assist
Limited ambulation prior to recent surgery as had difficulty with ulcer to RLE
It Takes a Village: The Interdisciplinary Team
Key element for successful amputee care program
Surgeon, Internist, Nurse, Prosthetist, Physical Therapist, Occupational Therapist, Social Worker, Nutritionist, Psychologist, Primary Care
Peer Support, vocational rehabilitation, recreational activities
Physical Medicine and Rehabilitation (Physiatry): Role on the Interdisciplinary Team
A physiatrist may assist the team in determination of amputation level as it relates to function, especially when uncertainty exists
Involve the physiatrist during the perioperative period
Utilize the physiatrist during the post op period to assist in the prosthetic prescription
Utilize the physiatrist when the amputee is in the community
Thank You