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.)
Prosthetic Feet
Medicare K-lvls
K4
*all children/athletes are K4!!!
Higher Activity
- Child, active adult, or athlete who exceeds basic amb skills including high impact, stress, or energy lvls
-
Components:
- Any foot approp. for the indiv’s activity lvl
What happens if a TTA, non-articulated foot gets measured for a ¾ inch heel but wears a 2in heel while @ work?
@ Knee joint angle and muscle activity?
- Knee joint angle→ Flexion
- Muscle activity→ more quads to offset flexion
What happens if a TTA, non-articulated foot gets measured for a ¾ inch heel but wears a 2in heel while @ work?
@ Hip joint angle and muscle activity?
- Hip joint angle→ Flexion
- Muscle activity→ More glutes to offset flexion
Rule of thumb:
Pylon must ALWAYS be what?????
VERTICAL TO GROUND!!!
Heel ht changes and effect on knee
Most prosth feet designed for _______
Standard ¾ in heel
Heel ht changes and effect on knee
DEC heel height does what????
- Creates EXT moment @ knee
- Leads to excessively stable knee
Heel ht changes and effect on knee
INC heel ht does what????
- Creates FLEX moment @ knee
- Leads to INstability of prosth. knee
Heel ht changes and effect on knee
Special prosth. feet made esp. for shoes w/ high heels****
see pics
Prosthetic Feet
Connection bw ____ and _____
Prosth. and ground
Prosthetic Feet
Classified by _________
Motions they allow or simulate
Prosthetic Feet
PT provides ________ and _____ to prosthetist
Current lvl of function and goals
Prosthetic Feet
Initial fabrication (“Bench Alignment”) designed for _____ to ______ inch heel
½ to ¾ inch heel
Prosthetic Feet
Advancements in new materials for the keel:
INCs in flexibility and responsiveness of foot
Prosthetic Feet
Advancements in ankle components:
Mvmt in 3 planes of anatomical ankle motion
Sag, Frontal, Transv
Prosth. Feets Examples
see pics and types
Prosthetic feet
NEW GENERATION VIDEOS!!!
See vids slide 27
Knee Stability: TFAs
3 factors that influence knee stability during Stance:
-
Individual, volitional control using muscular power
- Ex. Hip EXT IC→ MSt
- Alignment of knee jt w/ respect to wt. line
- Inherent mech. stability of knee unit chosen
Knee Stability
Ideally, alignment of 1._______, 2._______, 3._______ is one that allows individual to optimally use muscle w/ min. amt of alignment stability and still consistently stabilize knee
- Socket
- Knee
- Ankle
*Tradeoff bw/ stability and mobility w/in design
Trochanteric Knee Ankle (TKA) Line: Prosthetic term
A TKA line that passes IN FRONT OF KNEE JOINT AXIS:==>
Inherently STABLE Knee
- Incs EXTRINSIC knee stability (bench alignment bias)
- LESS muscle (quads) needed
- LESS responsive knee during stance
- Indicated for those w/ SHORTER RLs, poor mm control, K1/K2’s
Trochanteric Knee Ankle (TKA) Line: Prosthetic term
A TKA line that passes IN FRONT OF KNEE JOINT AXIS:==>
Indicated for who?
Inherently STABLE knee
- Indicated for those w/ SHORTER RLs, poor muscular control, K1/K2’s
Trochanteric Knee Ankle (TKA) Line: Prosthetic term
A TKA line that passes IN FRONT OF KNEE JOINT AXIS:==>
TKA-Anterior
see pics and EXPLAIN
What is the Bench Alignment?
Initial design of prosth.→ how its given to the pt @ first
“Shoe right off the shelf”
Trochanteric Knee Ankle (TKA) Line: Prosthetic term
A TKA line that passes BEHIND THE KNEE JOINT AXIS:==>
Higher lvl patient
- LESS stable and more mm req.
- EASIER transition to flexion reqd during swing
- more resp. into/out of subphases
- Timing of mm contraction→ more important
- Indicated for: those w/ good strength, proprio, longer RLs
Trochanteric Knee Ankle (TKA) Line: Prosthetic term
A TKA line that passes BEHIND THE KNEE JOINT AXIS:==>
Indicated for?
Higher lvl patient
- Good strength, proprio, LONGER RLs
TKA Line ANTERIOR
Think….
- MORE stable
- SHORTER RLs
- Less mm control needed
- K1/K2
TKA Line POSTERIOR
Think….
- HIGHER lvl pts.
- LONGER RLs
- LESS stable, MORE mm requirement
TKA Line:
Length of RL and the resultant weight line determines the mechanical knee adjustments (Ex. inc resistance in hydraulic or pneumatic knees) required:
SHORTER vs LONGER RLs
- SHORTER RLs== LESS intrinsic control==MORE resistance @ knee
- LONGER RLs== MORE intrinsic control==LESS resistance @ knee
TKA Line:
Length of RL and the resultant weight line determines the mechanical knee adjustments (Ex. inc resistance in hydraulic or pneumatic knees) required:
SHORTER RLs
SHORTER RLs== LESS intrinsic control==MORE resist. @ knee
TKA Line:
Length of RL and the resultant weight line determines the mechanical knee adjustments (Ex. inc resistance in hydraulic or pneumatic knees) required:
LONGER RLs
LONGER RLs==MORE intrinsic control==LESS resistance @ knee
*bc longer RL they have more control of knee!!!
TKA Line
_________relationship bw RL length and amt of muscular force needed to control prosth. knee
INVERSE RELATIONSHIP
*Longer RL== less amt mm force
*Shorter RL== More mm force
Ex. Hip EXT w/ shorter RL
TKA Line
Distinct ADVANTAGE for knee control w/ _____________ and _____________
LONGER RLs and Knee disartics
*Longer lever arms closer to knee jt. axis
TKA Line:
Shorter RLs req. TKA to be ________ to knee or Prosth. knee units w/ HIGH __________ (i.e hydraulic or pneumatic)
ANTERIOR to knee (bias towards more stability);
Knee units w/ high mechanical stability
Shorter RLs
just think you NEED more what?
STABILITY!!!!!! bc they have LESS mm control
Initial transfemoral socket design set in _________ degrees of flexion to pre-set hip EXTs and minimize anterior pelvic tilt (lordosis) compensation
5 degrees
*See pics of design for shorter RL/longer RL vs normal
Shorter RLs typ have _________ prosth control and require (bench) alignment of knee axis to be placed _________ relative to wt. line
DECREASED; ANTERIOR
Knee Stability:
2 extremes of mechanical (extrinsic) knee stability:
- Manually locked knee w/ ultimate mech. stability
- Single axis knee (unlocked/free swinging) w/out any stability
Knee Stability:
2 extremes of mechanical (extrinsic) knee stability:
1.Manually locked knee w/ ultimate mech. stability
Where does mobility come from?
Is alignment of knee important still?
- Mobility comes from hip
- Alignment not important if locked
Knee Stability:
2 extremes of mechanical (extrinsic) knee stability:
2.Single Axis knee (unlocked/free swinging) w/out any stability
Where does stability come from?
Hip, mechanical ankle
Knee Stability:
2 extremes of mechanical (extrinsic) knee stability:
Where do hydraulic and wt. activated knees fall on the mechanical stability continuum?
More dynamic==More freedom
Pelvic Stability: Quadrilateral socket
Most stabilization in ______-_______ direction w/ little to keep femur from drifting laterally
Ant-Post direction
Pelvic Stability: Quadrilateral socket
Most stabilization in Ant-Post direction w/ little to keep femur from drifting laterally
What happens @ pelvis as a result?
Causes pelvis to drop when intact limb is in swing phase
*Trendelenberg→ hip drop away from prosth. side
Pelvic Stability: Quadrilateral Socket
Most stabilization in A-P direction w/ little to keep femur from drifting laterally
Causes pelvis to drop when intact limb in Sw phase (Trendelenberg)
To compensate, what does amputee do?
Amputee will lurch laterally towards prosth side (opp of Trendelenberg) to improve control inside socket and clearance of intact side (during prosth. stance/single limb support phase)
Pelvic Stability: Quad socket
Most stabilization in A-P direction w/ little to keep femur from drifting laterally
Causes pelvis to drop when intact limb in swing (Trendelenberg)
Pt will compensate by lurching laterally towards prosth. side to improve control inside socket and clearance and clearance of intact side (during prosth.stance/single limb support phase)
What ensues?
How are these issues corrected?
- Widened BOS and high energy cost ensues
-
These issues are corrected w/ IRC socket→ holds femur in a normally ADD’d position in stance allowing for:
- Lvl pelvis
- Improved qual of gait
IRC socket holds femur in ________ position
Normally ADDucted position
used to correct Trendelenberg and compensations of Trendelenber in Quadrilateral socket
IRC socket
TFA: Gen Prosthetic Considerations
Most important influence on functional outcomes and return to IND is the _____ and _____ of socket fit***
quality and comfort
TFA: Gen Prosthetic Considerations
Quality and comfort of socket fit***
Must comfortably what?
- Contain all soft tissue in sitting and standing
- Provide adeq. relief for bony prominences
- Distribute stabilizing pressures equally
- Provide adeq. WB surface for the ischial/gluteal region***
TFA: Gen Prosthetic Considerations
Donning prosth must involve
Educating Pt. AND family
TFA: Gen Prosthetic Considerations
Too many cotton plies….
Talk about this…
- Too MANY (cotton) plies (RL too thick) → RL will NOT fully descend into socket**
-
Too FEW and limb will descend too far
- == incd distal pressure/pain OR medial socket pressure in groin
** remember we want TOUCHING but NOT WB!!!
TFA: Gen Prosthetic Considerations
Suction suspension
More skill involved
- Before valve is replaced must have total skin contact
- Finger in valve to check where limb is***
TFA: Gen Prosthetic Considerations
Biggest obstacle
Fluctuating edema/volume
*inconsit. fit
*alters quality of gait
TFA: Gen Prosthetic Considerations
Convince pt.
Convince pt. to be faithful w/ pressure/volume mgmt @ home w/ shrinkers, wrapping.. etc
*for fluctuating edema/volume
TFA: Gen Prosthetic Considerations
First few mos w/ no prosth. donned
Use of a shrinker or elastic wrap CRUCIAL!!!
*For fluctuating edema/volume
TFA: Gen Prosthetic Considerations
Proper total contact fit will:
- Distribute socket forces equally
- Reduce pressure over bony proms.
- Promote venous return
- Aid in control of edema
TFA: Gen Prosthetic Considerations
Consider SHORTER RLs!
- Present suspension probs
- Result in DECd Control of prosth. knee (Stance)
- INCd energy expenditure
TFA: Gen Prosthetic Considerations
Sitting:
More important to most TFAs than standing or walking!!
- Lower Ant. rim (IRC vs. Quad socket)
- Must be able to flex to 90degs @ hip
-
Standing ← → Sitting will cause change in negative pressure
- MINMIZED by iso. contraction of the thigh expanding the mm’s to maint. negative pressure gradient
***TAKE HOME MESSAGE:
- WHO is wearing prosth?→ PLOF, etc.
- What are the GOALS of the pt?→ keep them involved
- What is there OCCUPATION?→ sitting? standing?
- What are there HOBBIES/ACTIVITY LEVEL?
- What is their PERSONALITY?
-
The Ideal Prosthetic Foot:
- “Looks and feels good”
- Allows for efficient walking on varying surfs.
- Achieves an equal step length of both amputated AND intact limbs
VIDEO REVIEW!!!!!!
SLIDE 49*****