Lower Extremity Prosthetics Flashcards
(100 cards)
1
Q
Reasons for LE Prosthetics:
A
Disease 70% vascular related
Trauma 22%
Congenital birth defects 4%
Tumors 4%
2
Q
Check Socket or Diagnostic Socket
A
A transparent socket used to aid in assessing prosthetic fit.
3
Q
Definitive Prosthesis
A
A prosthesis that is intended for long term usage, comfort, fit, cosmetic appeal and durability. Usually fit once the residual limb stabilizes.
4
Q
Pistoning
A
refers to the residual limb moving up and down within the socket while walking
5
Q
Preparatory Prosthesis
A
Initial prosthesis that may or may not include definitive components. It is intended for temporary use to allow the patient to begin therapy for gait training. It is expected that it will need to be replaced within 3-9 months due to changes in the residual limb
6
Q
Socket liner
A
soft interface used between the hard socket and residual limb. These can be made of various types of gel, socks or soft foams
7
Q
Suspension Sleeve
A
an elastic tube made of varying materials that is first pulled over the outside of the prosthesis and then rolled up onto the thigh once the prosthesis is put on
8
Q
C-Leg
A
The Otto Bock C-Leg features a swing and stance phase control system that senses weight bearing and positioning to provide the knee’s microprocessor information about the amputee’s gait, thus promoting smoother ambulation. The outer shell houses a hydraulic cylinder, microchip, and rechargeable battery
9
Q
energy storing foot
A
A prosthetic foot designed with a flexible heel. The heel stores energy when weight is
applied to it and releases this energy when weight is transferred to the other foot
10
Q
Ischial containment socket
A
In some amputation cases, usually those of the HP or HD, this socket is used to
support the ischium
11
Q
multiaxis foot
A
The multi-rotational axis allows for inversion and eversion of the foot, and it is effective for walking on uneven surfaces.
12
Q
pylon
A
A rigid structure, usually tubular, between the socket or knee unit and the foot that provides a weight bearing, shock-absorbing support shaft for the prosthesis
13
Q
suction socket
A
Mainly for use by AK level amputees, this socket is designed to provide suspension by means of negative pressure vacuuming. This is achieved by forcing air out of the socket through a one-way valve when donning and using the prosthesis. In order for this type of socket to work properly, the soft tissues of the residual limb must precisely fit the contours of the socket. Suction sockets work very well for those whose residual limbs maintain a constant shape and size
14
Q
Apply post-operative protector:
A
0-4 weeks
15
Q
Incision fully healed; cast for prosthesis
A
5-9 weeks
16
Q
Sutures removed; limb shaping
A
3-5 weeks
17
Q
Pre-prosthetic training period from presurgery to temporary device
A
0-2 weeks (could start before)
18
Q
Ongoing therapy and prosthetic adjustments
A
4 months-6/7 months
19
Q
Receive permanent prosthesis
A
6/7 months-1 year
20
Q
Primary post-operative concerns:
A
Protection of residual limb Compression-reduce post surgical edema Maintenance of ROM Pain Management- Pain vs Phantom pain/sensation Maintain Strength and cardiac reserves
21
Q
Types of protection for residual limb:
A
simple splint
post operative cast
removable post operative cast
weight-bearing post operative device
22
Q
Post-op evaluation
A
History Living situation Support network Work Goals
23
Q
Tubular Gauze
A
Used for bulbous, sensitive limbs
double layering of material
same advantages and disadvantages as ace wrapping
uniform compression
24
Q
Prosthetic Shrinker
A
Compression sock that is used to help control swelling in the residual limb and help shape the limb in preparation for prosthetic fitting
25
Prosthetic Socks
Socks of varying thicknesses or ply. The higher the ply number, the thicker the sock. They allow a patient to manage small volume changes in limb size and add to the comfort of prosthesis. They can be made of different materials, including wool, silicone and synthetic fibers
26
Compression garments:
ace wrapping
shrinkers
post operative casts
27
Who are our patients?
60% are 45 years or older
85% lose limbs to diabetes or related vascular disease
Multiple chronic health concerns
Deconditioned, Flexion contractures, Overweight
28
What determines the
| prosthetic Rx?
```
Functional ‘K’ level
Physical Concerns
Vocational and Leisure Activities
Cognitive skills
Home environment / distance from prosthetic center
Insurance Coverage
```
29
Physical Concerns of prosthetic Rx?
Level of amputation
Disease pathologies
Body weight
Skin integrity
30
Functional Level 0
no ability or potential for weight bearing or transfer
31
Functional Level 1
Ability or potential to transfer and ambulate within the household with an assistive device
32
Functional level 2
Community ambulator with the ability or potential to traverse minor environmental barriers, fixed cadence
33
Functional Level 3
Community ambulator with the ability or potential to traverse all environmental barriers with a variable cadence
34
Functional Level 4
ability or potential for prosthetic ambulation that exceeds basic ambulation skills, exhibiting high impact, stress, or energy levels. Typical of the prosthetic demands of the child, active adult, or athlete
35
Physical Concerns
```
Amputation length
Weight restrictions on components
Vocational and Leisure Activities
Skin Integrity
Peripheral Neuropathy/ hand strength
Disease pathologies
```
36
Socket design
Muscle contouring
| Total contact
37
Socket interface
Socks
| Gel liners
38
Suspension
Sleeve
Suction
Pin locks
Belts
39
Principals of
| Socket Design
Contour, relief and support for functioning muscles
Stabilize Skeletal Structure
Position Muscles to optimize strength
Minimize applied pressures to neurovascular structures
Distribute forces within socket over the entire limb
40
Trans-tibial Socket design and Interface
Patellar Tendon Bearing (PTB)
| Total Surface Bearing (TSB)
41
Where is weight bearing concentrated in PTB?
patellar tendon
medial tibial flare
gastrocnemius
42
PTB complaints:
excessive pressure in popliteal fossa or patella tendon
| Older style of Prosthetic sockets developed in 1959 after WWII
43
Total Surface Bearing (TSB)
Pressure distributed over entire limb surface.
The entire surface of the residual-limb is in total contact with socket while every unit area is under compression to its proportionate tolerable level
44
Hydrostatic Design Sockets
considered TSB
Bearing design but they utilized compression chambers to achieve a uniform fit.
Fluid in chambers utilized Pascal law of fluids that apply pressure uniformly in all directions.
Also uses a silicone suction suspension sleeve
45
Socks
maintain socket fit
46
Nylon Sheaths:
help wick perspiration from skin
47
Gel Liners
provide protection against shear and pressure and can be integrated into suspension. Key component of TSB sockets. High friction inner and low friction outer allows decrease skin shear
48
Types of gel liners
Silicone elastomers, silicone gels, urethanes
49
Transtibial Suspension
```
Cuff / Waist belt / Joints & Lacer
PTB SC/SP
Sleeve – many variations
Locking liners/seal in
Active suction
```
50
Sleeve Suspension
Older style of prosthesis suspension but a versatile
Neoprene, Latex, Gel lined sleeve that fits over the top of the prosthesis
Not durable
Create negative pressure seal
Work w/other suspension methods
51
Three suspensory forces attributed to the sleeve are
1. negative pressure created during the swing phase,
2. friction between the residual limb and the socket, and
3. longitudinal tension in the sleeve
52
Sleeve suspension advantages
Simple and effective means of suspension.
Helps minimize socket pistoning.
Does not create proximal constriction.
53
Sleeve suspension disadvantages
Provides no added knee stability.
Suspension is greatly decreased if the sleeve is punctured.
Perspiration may build up under the sleeve and create skin irritation or hygiene problems.
Must be replaced regularly.
Sleeves may restrict full knee flexion and require good hand function to don and doff.
54
Elevated vacuum systems try to
reduce pistoning, perspiration and provide better linkage between user and prosthesis.
55
Benefits of Elevated Vacuum Systems:
Better pistoning
Better cirulation
Soft tissue hydrated
56
Trans-femoral socket design
Quadrilateral
Ischial Containment
M.A.S.
57
Quadrilateral Socket
Wide M-L / narrow A-P
Weight bearing through ischium and Gluteal muscles
Can be used effectively by healthy, muscular individuals
58
Ischial Containment
Narrow M-L dimension
Ischium and ramus contained within socket
Maintains natural femoral adduction
Increased medial lateral stability during ambulation
59
Muscle Contouring
built-in relief for concentrated pressure points
an aggressive, more intimate fit of the pelvis bone
improved M-L control
increased A-P stability
reduced socket rotation on the
Controls alignment of Femur
anatomically correct channels to encourage muscle contraction during gait
ability to increase muscle tone in residual limb
60
MAS Socket: Marlo Anatomical Socket Medial Ramus Ischial Containment
Narrow M-L Anatomical Socket Shape
Good M-L control due to boney lock
Increased Range of Motion throughout gait cycle
Increased sitting Comfort
61
Double Wall Socket for Transfemoral
Socket within a socket
transfemoral prosthesis that fits intimately and provides increased control and security
larger range of motion
62
Trans-femoral Suspension Belts:
Silesian
Elastic Removable
Waist belt with pelvic band and hip joint
63
Trans-femoral Suspension Suction:
Incorporated into socket
| Incorporated into liners
64
Trans-femoral belt suspension:
May be used as primary or auxiliary form of suspension
| Rotational stability / mediolateral pelvic stability may be enhanced with the addition of hip joint
65
Advantages of belt suspension
Can be simply applied
Rotational control for shorter limb length
Positive point of attachment over contra-lateral pelvic crest
66
Disadvantage of belt suspension:
Can cause skin irritation
Silesian Belt can not be removed for laundering
Removable belts are bulky and retain body heat
67
Trans-femoral suction suspension:
Air expulsion valve facilitates suspension by negative air pressure applied with sock or other pull on device
applied with lotion or other lubricant
68
Disadvantages of Trans-femoral suction suspension
Must Have stable limb volumes
Less effective on limbs with irregular contours or scars
Short residual limbs may require secondary suspension
Perspiration can be a problem
69
Advantages of Trans-femoral suction suspension
Increased Proprioception
| Less vertical displacement of prosthesis during ambulation
70
Disadvantages of suction liners:
Can cause fleshy limbs to elongate during swing
Lock mechanisms add additional length to socket
Liners need meticulous hygiene to avoid odors and skin irritation
71
Advantage of suction liner:
Easy donning
| Can be adjusted for volume fluctuations
72
Flexible
Socket and Frame
Construction
Improved comfort at brim
Ability to modify for volume fluctuation
Cut outs in frame allow for increased sitting comfort, as well as active muscle contraction during gait
73
Function of Prosthetic Knees
Provide Security against collapse when prosthesis is loaded
Provide shock absorption at heel strike
Flex during preswing and swing phase to advance prosthesis
Slow down extension during terminal swing to prevent damage to knee joint
74
Functional level 1 choices of Prosthetic knees:
locking knee
single axis friction
safety-knee-stance; activated breaking mechanism
75
Manual Lock
Functional Level 1 – 2
Transfer prosthesis or limited walking on level surfaces
Simple design, provides a non-flexing knee while standing/ambulating
Patient must unlock knee manually to sit
If patient falls, the knee will not collapse under them
“knee of last resort”
76
Friction Knee
Functional level 1 - 2
Transfer prosthesis or limited walking on level surfaces
Simple design, functionally acts like a simple door hinge.
Friction setting allows for only one walking speed
Friction plates wear and will require regular maintenance and replacement
77
Single Axis
Less moving parts and simple design
Lower fabrication costs
Less stable at heel strike
One axis to absorb gait stress
78
Polycentric
```
Inherent stability at heel strike
Easy to initiate swing phase
Tend to be heavier
Increased maintenance
Greater inherent mechanical stability resulting in greater stance stability
Good choice for short residual limbs
```
79
Stance Control Knee
Functional Level 1-2-3
Provides added stability during a missteps or uneven surfaces
Breaking mechanism locks the knee during stance phase
Most popular knee fit in USA
Light weight
Break will wear and knee will fail without proper adjustment and maintenance
Locks’ in up to 20 degrees of flexion
Best suited to geriatric or individuals with weak hip extensors
80
Fluid and Pneumatic Swing Control
Extension and flexion resistance controlled for more efficient gait
Eliminates terminal impact
Heavier
More expense
Some models include stance flexion
Hydraulic can be used to descend stairs step over step
Can be either single axis or polycentric linkage
81
Hydraulic Swing Phase Knee
Functional level 3-4
Hydraulic mechanism provides resistance to flexion/extension during swing phase
Provides variable cadence; ability to change walking speeds without hesitation
Tend to be heavier due to hydraulic fluids in cylinder
Require regular maintenance
82
Microprocessor Swing
Functional Level 3-4
Provides resistance to flexion/extension during swing phase
Enables variable cadence; ability to change walking speeds without hesitation
Added expense due to computer technology
Maintenance is essential
83
Microprocessor Swing/Stance
Functional Level 3-4
Some level 2 requiring added stability
On board computer analysis gait 50 times per second and performs continuous hydraulic adjustments to ensure stability, security and efficiency in swing and stance.
Provides microprocessor hydraulic controlled stance and swing phase function
Stance stability is engaged and disengaged as necessary
Provides maximum cadence response over a wide range of functional applications
84
Microprocessor Knee
Utilize microprocessor controls to adjust resistances according to ‘real time analysis’ of gait
‘Stumble Recovery’
Typically involved authorization process
Expensive initial cost and repairs
85
Power Knee
Motor powered to simulate knee function without relearned motor strategies using alternative muscle groups. The knee mechanically replaces the knee function.
86
Specialized Adaptors/Knee
water knee
positional rotators
quick disconnects
87
Functional Level 1 feet:
single axis foot
| SACH foot
88
Single axis foot
provides plantar –flexion moment at heel strike improving stability
89
SACH
Solid Ankle Cushion Heel foot
| SACH foot is simple design, low cost lowest function
90
Functional Level 2 feet:
multi-axial foot
| flexible keel foot
91
Multi-axial foot
provides plantar and dorsi-flexion as well as inversion, eversion and rotation, reducing shear forces on limb and greater stability on uneven surfaces
92
Flexible Keel foot-
SAFE Foot internal flexible keel permits tri-planar movement with an easy roll over
93
Functional Level 3 feet:
no restrictions
94
Dynamic response/energy storing feet
absorbs energy” during mid and terminal stance
“releases energy” at toe off
More energy efficient gait
Can incorporate pylon for increased reaction
Can incorporate inversion/eversion
Lightweight and durable
Body Mass and activity sensitive
95
Multi-axial dynamic response feet
Provides Multi axial compliance to uneven ground
Dynamic response at toe off for more dynamic walkers
Classified as “Energy Storing”
Split toe allows for inversion eversion
96
Specialty Feet
```
micro-processor controlled ankle (adjusts plantar and dorsiflexion)
adjustable heel height
special uses (running, swimming)
```
97
Vertical Shock and Torque Absorbers Advantages
Reduce impact at heel strike
| Reduce rotational shear forces within socket
98
Vertical Shock and Torque Absorbers Disadvantages:
Increased weight
Increased maintenance and cost
Clearance an issue for long residual limbs
99
Syme limbs prosthetic characteristics:
Light enough to wear comfortably
Ability to supply the equivalent of foot and ankle function
Lengthening of the limb to adjust for loss of the talus and calcaneous
Distribution of the high forces developed in the ankle area
Provision of rotary stability about the long axis
Provision of shock absorption
Suspension during swing phase
Readily donned without requiring multiple non-cosmetic, difficult fasteners
Adjustability to relieve pressure along a sensitive scar line
Cosmesis
100
SAFE foot:
stationary-ankle-flexible-endoskeletal
makes it easier for the amputee to walk over uneven terrain
Foot has the same action as the SACH plus the ability for the sole to conform to slightly irregular surfaces (mild inversion eversion compontent of motion)
