L4: TFA Rehab and Prosthetic Feet Flashcards
OBJECTIVES:
- ID and special considerations and barriers during rehab of pts w/ a TFA
- Understand the proper alignment and fit of various transfemoral prosthetics to maximize gait and function
- Understand the concept of the TKA line and how its location effects each individual LE joint and subsequent control of the transfemoral prosthetic devices
- ID various prosth. foot components and the advantages and disadv’s of each
Prosth. Feet
Classifications:
-
NON-articulating
- SACH (Solid Ankle Cushioned Heel)
-
Articulating
- Single and Multiaxial (like a joystick)
-
Elastic Heels
- SAFE (Stationary Ankle Flexibility Endoskeletal)
-
Dynamic Response or Energy Storing
- Seattle
- Flex Foot
- Carbon Copy
Dead giveaway for the Multi-Axial foot
O-Ring
This is the foot they have on at first
SACH foot
Solid Ankle Cushioned Heel
SACH Foot
*Non-articulating foot
ADVs vs. Disadvs
- ADVs
- NO moving parts: durable→ little maint.
- Excellent for shock absorb.
- Low $
- Good for temporary prostheses
- Disadvs
- Lack of flex.→ partic for uneven surfaces
- NOT approp. for incd rates of walking or active indiv’s
Good foot for temp. prosth.
SACH
*also good shock absorb
Single Axis Feet
-
Allow 15degs PF (CC)
- compress of rubber bumper post. to axis of prosth.
- rate of PF controlled by bumpers density in LR
-
Allow 5-7degs DF (CC)
- anterior bumper compress. slowing forward mvmt of prosthetic shank
- Incd sag. plane motion
Single Axis Feet
Allows _______ degs PF (CC)
Allows _____degs DF (CC)
15degs PF
5-7degs DF
@ what stage of gait is at leas 5-7degs DF MOST needed?
MSt→TSt
ECC closed chain DF controlling tibia moving on fixed foot
Single Axis Feet
ADVs vs Disadvs
- ADVs
- Stable foot flat pos. earlier in stance
- INCd knee stability reducing knee flex moment
- moves wt. line ANT quicker– less likely to buckle
- Quick adjs to durometer (compression of bumpers)
- Disadvs
- Heavier vs SACH
- more parts=more repairs
Multi-axis/Articulating Designed Feet
**Inv/Eversion→ computerized OR split toe foot
- Bumpers BUT allows for motions in transv and coronal (frontal) planes→ In Add. to sagittal
- Incd inversion, eversion, rotational motion and control
- → better accommodation to changing walk surf’s
- Allows foot to absorb torque forces that would normally translate proximally to RL
Mulit-Axis Feet
*think more Inv/Ev and Rotation — absorbs forces
ADVs vs Disadvs
-
ADVs
- Accommodate to changing terrain
- Reduce torque forces to RL
- Quick adj. to durometer to accommodate indivs wt and function lvl
-
Disadvs
- LESS stable vs nonaxial
- **More deg of freedom===LESS stability
- More parts=more maint.
- heavier
- LESS stable vs nonaxial
Rule of Thumb:
MORE degs of freedom======
LESS stability!!!!!
Elastic Keel Feet
- Elastic keel gradually incs tension from heel strike thru MSt to push-off
- *similar to anatomical feet
- Foot loaded in TSt, inc’ing tension on “plantar bands” placed in keel— creates rigid lever for smooth trans. to swing
Elastic Keel Feet
*think “Plantar bands” one!
ADVs vs Disadvs
-
Adv’s
- SMOOTHER gait pattern bc no mech. rocker motions during Stance
- Flex. of keel eases tasks like stair negot. and inc walking
- Simple design
-
Disadvs
- “spongy feel” → not liked by more active users
Prosthetic feet usually progress to THIS….
Dynamic-Response Feet
Dynamic-Response Feet
-
Need to absorb and store forces during Loading and release these forces in PSw/push-off
- running/jumping
- Mats used in keel combined stiff and flex.
-
Stiffer keel=== LOSS of inv/ev.
- split toe advancements
-
More force on forefoot (running)== greater the material compresses === more energy is stored
- Carbon-graphite material
What is crucial for prosth. foot Rx???
PLOF!!!
What are they going to be doing? Where? Prev activity lvl???
Dynamic-Response Feets
Advs vs. Disadvs
-
ADVs
- BEST option for high demand acts.
- Accommodates quickly to changing grades of terrain and speeds
- Made to order specific to user
-
Disadvs
- Mat. used to make foot stronger often produces feeling of being stiff and unaccommodating
- $$$
Dynamic-Response Feets
VIDEOS!!!
SEE VIDEOS WHEN STUDYING!!!
SLIDE 16
Prosthetic Feet→ Role during Stance phase
Initial Contact
Absorb shock*
Prosthetic Feet→ Role during Stance phase
Initial Contact
Cushioned heel→ SACH
Softer heels vs. Firmer heels
Role→ absorb shock
-
Softer heels
- lighter pts
- allows quicker foot flat stability
- more knee stability
-
Firmer heels
- heavier pts
- slows transfer of wt. midfoot and forefoot
Prosthetic Feet→ Role during Stance phase
Initial Contact
*Absorb shock
- Compression of heel simulates ecc. contract. of DF towards foot flat
- Provides for a normal knee flex moment as gait progresses to LR
Prosthetic Feet→ Role during Stance phase
Midstance
*Accommodation of terrain
Prosthetic Feet→ Role during Stance phase
Midstance
*accommodation of terrain
- Accomplished to varying degs by diff types of ankle-foot componentry:
- non-artic, single-axis, multi-axis, etc..
-
Transition from PF→ DF as shank/pylon moves over a fixed foot (ankle rocker)
- Accomplished in prosthesis by flex. of keel
Prosthetic Feet→ Role during Stance phase
Midstance
Transition from PF to DF moving over fixed foot (ankle rocker)
Accomplished in prosth. foot how?
Flex. of keel
Prosthetic Feet→ Role during Stance phase
Terminal stance to Preswing
- Provides simultaneous TSt support and toe rocker moment w/ flexible keel
- Reduces force to sound side aiding in balance and smooth transfer of wt.
- Control of heel rise (TSt) during the toe rocker in TSt and progression onto forefoot
- see other card how this accomplished****
- Depending on material and/or energy storing capability of material in foot is how eff. push-off is
- Sligh spring action that simulates rapid knee flex (limb shortening during PSw)
Prosthetic Feet→ Role during Stance phase
Tst→PSw
Control of heel rise during the toe rocker in TSt and progression onto forefoot
How is this accomplished in prosth. foot?
*Accomplished by LENGTH of keel
- Keel too SHORT→ EARLY heel rise and PREMATURE knee flexion (buckling)
- Keel too LONG→ DELAY heel rise and knee EXT moment occurs
Control of heel rise during toe rocker in TST and progression to forefoot
If Keel too SHORT ===
EARLY heel rise
Premature knee flex.
*Buckling
Control of heel rise during toe rocker in TST and progression to forefoot
If Keel too LONG
DELAY in heel rise
Knee EXT moment
Prosthetic Feet: Role during Stance Phase
SACH foot and heel compression
IC→ MSt
Durometer (resist. to compression) of heel cushion
Prosthetic Feet: Role during Stance Phase
Single axis foot
IC→LR
Durometer of heel and PF stop or bumper
Prosthetic Feet: Role during Stance Phase
Single Axis Foot
LR→TSt
DF bumper and firmness of keel
Medicare→ Prosthetic Feet
K-lvls
*REMEMER ALL CHILDREN ARE K4’S!!!!!!!!!!
Prosthetic Feet
Medicare K-lvls
K0
Nonambulatory
- Cannot ambulate or transfer safely w/out assist.
- Prosth. does not enhance QoL or mobility
- Components: NONE
Prosthetic Feet
Medicare K-lvls
K1
Lmtd or unlmtd household ambulation
- Can use prosth. for transfers or ambulation on LEVEL surfs @ fixed cadence
- Components:
- SACH
- Single Axis
Prosthetic Feet
Medicare K-lvls
K2
Limited community ambulation
- Can traverse LOW lvl environmental barriers such as curbs, stairs, uneven surfs
- Components:
- SACH
- Flex (elastic) keel
- Single Axis
- Multi-axial
Prosthetic Feet
Medicare K-lvls
K3
Community Ambulation
- Can amb. w/ variable cadence and traverse MOST environmental barriers.
- Has vocational, therapeutic, or ex. activities that demand prosth. use beyond simple loco.
- Components:
- SACH
- Flex (elastic) keel
- Single axis
- Multiaxial
- Energy storing (dynamic resp.)