prosthesis Flashcards
articulated
a mechanical ankle joint
single axis
multi axis-allow for supination and pronation
5 things needed in a prosthesis
- stable base
- shock absorb
- heel to toe gait
- looks
- cost
non articulated
solid ankle foot piece bolted to the shank
material in front piece will allow for adaptation on uneven surfaces
energy storing prosthetic feet: when is it stored, when is it used
Midstance–>heelrise: store energy
Toe off–> early swing: use energy
plantar flexion bumper
compress at heelstrike, allow a controlled plantarflexion for going into footflat
Dorsiflexion stopper
control the amount of dorsiflexion as the person comes over the foot
midstance–> heelrise
SACH Foot
energy
artic
doesnt store energy
nonarticulated
controlled plantarflexion with cushion heel
flexible rubber forefoot to allow MTP extension
Seattle Foot
energy stored
nonarticulated
C shaped material that is compressed midstance–>heelrise
energy return as push off
Carbon Copy II Foot
non articulated
store energy
compressible heel
roll over foot and plantar carbon fibers are stretched: then energy is returned
SAFE Foot
Stationary Attach Flexible Endoskeleton
not such a good energy storing
nonarticulated
adaptable, flexible mid/forefoot
STEN foot
not so good energy storing foot
not articulated
cushion heel
rigid keel with flexible plugs in between sections
Flex Foot
energy storing foot
non-articulated
lightweight and resilient (carbon fibers)
expensive
as go into HS compress and then when go into terminal stance and bring it forward there is a separation when take the weight off
flex walk
same as flex foot
but flex walk has a shorter lever arm
college park true step
store energy
non-articulated
2 long toe levers, flexible keel
lightweight material
arch flattens and recoils
Shank: Exoskeleton
older
more durable but heavier
made of hard plastic laminate
Shank: endoskeleton
more common
metal pole central and then a cosmetic covering over it
metal pole allows for adjustments: in rehab start here and then when all the settings are good they put a cosmetic covering
PTB
what is it where is WB bulge walls channels
BK
patella tendon bearing socket: for a below the knee amputation
WB:
- infrapatella tendon–shelf for the infrapatella tendon on anterior wall
- medial tibial plateau
- muscle belly of anterior tibialis: palpate lateral to tibial crest
Popliteal Bulge: on the posterior wall have a convexity that caves in to provide anteriorly directed force to keep patella on patella tendon shelf and improve WB on infrapatella tendon
walls:
anterior: comes up to mid tibia and flares out
medial and lateral: higher than anterior, up over femoral condyles
posterior wall: lowest wall to allow for knee flexion in sitting
channels and cavities:
hamstring channels are lateral and medial to popliteal bulge: go into socket on either side of popliteal bulge for hamstring tendons
Popliteal Bulge:
BK
in the PTB for the below knee amputation
on the posterior wall have a convexity that caves in to provide anteriorly directed force to keep patella on patella tendon shelf and improve WB on infrapatella tendon
walls of PTB
BK
anterior: comes up to mid tibia and flares out
medial and lateral: higher than anterior, up over femoral condyles
posterior wall: lowest wall to allow for knee flexion in sitting
TSB
what is it
BK
total surface bearing socket
even pressure distribution in residual limb, custom made for fit
doesnt have patella tendon shelf usually
-not good if limb is changing size or if sensitive areas cannot tolerate the pressure
Types of Suspension
BK
BK
- gel liner
- pre-lite liner
- supracondylar cuff
- supracondylar wall
- supracondylar suprapatellar walls
- Thigh corset suspension
- fork strap attached to waist belt
- over the knee sleeve suspension
- locking gel liner suspension
Gel Liner
what is it
pros (2)
cons (3)
BK
suspension: see more with the TSB
silicone, polyurithane cushioning on residual limb
PROS
- better to reduce pistoning
- even pressure distribution (comfort)
CONS:
- not as durable, breakdown overtime
- issue with prespiration: sweating can cause skin rashes (eventually sweat glands adapt)
- harder to don and doff
Pe-lite liner
BK
see more with PTB
foam mold of the residual limb that goes into the liner sometimes called a soft insert
Supracondylar Cuff
BK
cuff attached on medial and lateral side of prosthetic and goes around the limb
good for fluctuating edema
**bad in that more likely pistoning
supracondylar walls
BK
medial and lateral wall over the condyles of the femur
–less desirable
supercondylar suprapatellar walls
BK
high medial, lateral walls over condyles of femur
anterior walls–come up as high as the medial and lateral wall
they can sit but kneeling is difficult
USE FOR A VERY SHORT BK
Thigh Corset Suspension
BK
for below the knee amputation
mechanical knee over their knee
Pro:
- for fluctuating size of residual limb
- pressure intolerance: force through soft tissue of thigh takes some of the WB away from the residual limb
CON:
- heavy
- mechanical jt can break down
- can make noise
- moving parts
- can cause atrophy in the quads and hamstrings bc pressure on soft tissue isn’t contracting to the same extent (like an abdominal binder)
Fork strap attached to waist belt
BK
for below the knee amputation
the fork strap can also be used with the superior portion of the supracondylar cuff (SC cuff)
less cosmetic
adds bulk
Over the knee sleeve suspension
BK
for below the knee amputation
uses suction: needs to be well fitting
valve to push air out of socket–dont want air in the socket
over the knee sleeve
it goes over the knee and is made of polyurithane/neoprene material and it creates suction suspension
NOT GOOD FOR LIMB THAT CHANGES IN SIZE
Locking Gel Liner Suspension
BK
for below the knee amputation
suction and locking pin–not for a fluctuating limb
gel liner with a pin at the end that clicks into the prosthesis (put on with 3-4 clicks release button to take off)
DECREASED PISTONING
REQUIRES A RESIDUALLY STABLE LIMB
Iceross Seal in Sleeve
BK
has ring things to prevent the air from getting into the socket
suction suspension
does not go over the anatomy with walls
Gel Liner
VS
Pe-Lite Liner
BK
Gel Liner:
- -less pistoning/socket fit
- -comfort/better pressure distribution
- -pressure distribution throughout residual limb
Pe-Lite Liner
- -more durable
- -easier to put on and off
- -cheaper
- -doesnt have the prespiration issues
suspensions:
Suction Suspension
BK
over the knee sleeve
locking gel liner
hypobaric gel liner
icercross
Suspension:
Anatomical Contour
BK
SC wall: supracondylar wall
SC SP wall: supracondylar suprapatellar wall [for short residual limb]
Suspension:
with straps
BK
- SC cuff
- supracondylar cuff
suspension:
hinges
BK
thigh corset: straps and hinges (the mechanical knee goes over a real knee)
Locked Knee Unit
AK
pull on anchor to lock knee into extension
(shorter because cannot flex the knee to shorten the limb in gait)
free knee unit
mostly free but can lock out
–able to lock when need more security
Types of Friction on a knee unit for AK
- Mechanical Friction: femoral and tibial surfaces abutt eachother, can adjust how tight the approximation is -FRICTION STAYS CONSTANT AMOUNT
- Hydraulic Friction: cylinder of viscous fluid creates friction, velocity dependent
- Pneumatic Friction: sealed chamber of air, velocity dependent
C Leg
AK
hydraulic friction
computerized knee unit: microprocessor to adjust friction and redistribute the fluid to change stability
weight activating break
AK
in mechanical/pneumatic/hydraulics
when WB through the knee joint the surfaces approximate on eachother and dont let the knee flex
do not have the breaking action unless you bear weight in the prosthesis
safety knee
AK
weight activating break
–if WB on the prosthesis it doesn’t let the knee flex beyond 20 DEGREES
in stance we dont flex the knee anymore–like when in swing, if WB through the prosthesis it wont flex beyond 20 degrees so you dont stumble
(WB on good leg to stand and to sit)
Internal Extension Aide
AK
spring in prosthesis helps the knee go into terminal extension –spring compressed in flexion and then recoil in extension
ensure complete extension and knee locks so that knee wont collapse when WB in gait
—-this is useful for the geriatric lock knee unit to help achieve that terminal extension to lock the knee
External Extension Aide
AK
rubber elastic band in front
runs from socket to anterior portion of the knee unit/lower shank
stretches in flexion and recoils in extension
Quadrilateral Socket
AK
- older: use for
1. fluctuating limb
2. limb that is not tolerant to pressure
walls: medial to lateral dimension is greater than anterior to posterior dimension (rectangle, wider medial to lateral)
ischial shelf: primary site of WB by Ischial Tuberosity and underlying soft tissue
concavities: (relief)
- medial to shelf: hamstrings
- lateral to shelf: glut max
- lateral to socket: bicep femoris
- anterior medial: adductor longus
- posterior medial: hamstring tendon
Scarpas Bulge: anterior wall has a convexity to provide posteriorly directed force to keep the IT on the shelf
concavities in the quadrilateral socket
concavities: (relief)
- medial to shelf: hamstrings
- lateral to shelf: glut max
- lateral to socket: bicep femoris
- anterior medial: adductor longus
- posterior medial: hamstring tendon
scarpas bulge
on the anterior wall to provide a posterior directed force to keep the IT on the shelf
indications for quadrilateral socket for AK
- older: use for
1. fluctuating limb
2. limb that is not tolerant to pressure
which way is the quadrilateral socket wider?
medial to lateral
ischial containment socket
AK
better pressure distribution
–more symmetrical shape for better pressure distribution
IT is contained (not on a shelf)
more total surface WB around the ischial tuberosity and overlying tissue but also near the inferior pubic ramus
difference between ischial containment socket and the quadrilateral socket
AK
the ischial shelf and the medial lateral being wider than the AP
Suspensions in AK
- Total Elastic Suspension belt (TES)
- Silesian Belt
- Pelvic Band Suspension
- Suction Suspension
Total Elastic Suspension Belt
AK
TES belt (like over the knee sleeve that is BK): partial suction with belt
uses partial suction–soft velcro material and neoprene material and expel air out of socket and use TES for added suspension
Silesian Belt
partial suction
comes up and over iliac crests
(like SC of BK)
Pelvic Band Suspension
AK
mechanical hip joint over anatomical hip joint
leather band encircles pelvis (like thigh corset of the BK)
hip joint with mechanical hip joint and a band that encircles the pelvis –add bulk and heavy but added support for suspension
does not use suction suspension
GOOD FOR RESIDUAL LIMB THAT FLUCTUATES IN SIZE
suction suspension
AK
AK
total suction
if you dont see any belts or straps or bands
easier to total suction AK than on BK because tissues more tolerant to suction
