Transfemoral/Hip Prosthesis components Flashcards
can you end weight bear with a knee disarticulation
yes
*also allows for more ROM
what are removed with knee disarticulations
femoral condyles
Van Ness Rotationplasty (VNRP)
tibia is attached to femur and rotated 180 degrees for ankle to act as knee
VNRPs are typically seen in pts with…
sarcoma of distal femur
what is the advantage to a VNRP? disadvantage?
it is very functional but not cosmetically appealing
2 socket designs for above knee
quadrilateral and ischial containment
what are two general goals for above knee prosthetics
1 - achieve M/L stability
2 - knee stability and security
ischial containment creates more of a _______ effect
cupping
which gives you more M/L and rotational control… quadrilateral or ischial containment
ischial c
quadrilateral socket gives compression on the _____ portion of the residual limb
anterior
*helps keep ischium where it needs to be
where does the pt sit with a quadrilateral socket
posterior shelf
with a quadrilateral socket, what do you rely on for control
muscles, there is no bony lock
how does a quadrilateral socket control rotation
by restricting muscle and tendon movement
the medial wall of a quadrilateral socket has a relief area for…
adductor longus tendon
the posterior wall of a quadrilateral socket has a relief area for…
glute max and hamstring tendon
the anterior wall of a quadrilateral socket has relief area for…
rectus femoris
what is the purpose of the lateral wall of a quadrilateral socket
to wrap around the trochanter
which one contains more limb volume… quad or ischial containment
ischial c
which one is usually preferred by pts… quad or ischial containment
ischial c
T or F: ischial containment sockets often include a flexible liner for comfort
T
the posteiror wall of ischial containment socket has a relief area for….
glute max
3 structural goals of a prosthesis
1 - structural support for skeletal system
2 - transfer support forces through soft tissue to femur
3 - stabilizes the femur into the hip in a natural position for posture and force
The medial lock of ischial containment socket contains and supports _________. The lateral lock supports ______ and maintains _____ control
ischial tuberosity
sub-trochanter
femoral
4 T’s of socket design/conform
1 - total contact
2 - total contouring
3 - total control
4 - total comfort
A shorter prosthetic allows for more ________
stability
what is the standard height for bilateral transtibial prosthesis and why?
18 inches b/c that is standard chair height
generally, above knee sockets are aligned in _______ degrees of hip adduction and ______ degrees of hip flexion
10
5
*add 5 deg to hip flexion contracture
what is the max hip flexion contracture that can typically be accommodated for?
30*
why is it extremely important to put hip flexion into the socket? (2)
1 - assist with weight bearing
2 - ensure TKA line is in front of knee
T or F: K-1 level can have a rotator
F: have to be K2 or above
What can a lack of hip flexion in the socket cause (3)
1) knee instability
2) inability to take proper length step
3) limited time on prosthesis
Too high of a heel will cause what?
knee buckling
T or F: adjustments to the knee of a prosthesis can be made
T
What are some pt-related reasons for prosthetic knee failure
1 - activity level has changed
2 - weight or activity has increased since initial fitting
3 - pt does not meet criterial for design and function of the knee
Why is it important for pts to follow up with prosthetist regularly?
because a prothesis is a piece of equipment and that equipment needs to be properly maintains. sometimes it fails.
Manual locking knees are used for what K-levels?
1 or 2
How does a manual locking knee work
The pt must manually unlock the knee to sit. If they fall, the knee will not collapse under them
What is the standard height for bilateral transfemoral prostheses
24 inches
What K-levels are friction knees for?
1 or 2
Friction setting allows for ______ walking speed.
one
T or F: friction plates require regular maintenance and replacement
T: they wear
Weight activated stance control knees are for what k-levels
1,2,3
this knee provides added stability during a misstep or on uneven surfaces
weight activated stance control
on a weight activated knee, a braking mechanism locks the knee during ______ phase
stance
What is the most popular knee fit in the US?
weight activated stance control
are polycentric or single axis knees more stable at heel strike
polycentric
________ knees shorten during swing
polycentric
*easy to initiate swing
is polycentric or single axis cheaper? which is heavier?
single axis
polycentric
How is stability achieved in a polycentric knee
the location of the “instant center” at full extension
hydraulic swing and stance (SNS) knees
provide hydraulic control during both stance and swing
what k-levels are hydraulic swing and stance knees for
3 and 4
This knee provides resistance to flex/ext during swing and stance and can provide stumble recovery and ability to walk down stairs/ramps
hydraulic swing and stance
in microprocessor knees, when weight is put on the toe the knee ______ and when weight is put on the heel the knee _______
flexes
extends
what k-levels are microprocessor knees for
3-4
*maybe 2
this knee provides max cadence response over a wide range of functional applications
microprocessor
disadvantages of microprocessor knee
1 - expensive
2 - maintenance is crucial
3 - charging
axillary suspension is often needed as a secondary to a suction prosthesis in pts who have…
volume fluctuations
what is an advantage to a liner with suction/lanyard?
pts can put it on while sitting as long as they have the dexterity
where is the static evaluation for a prosthetic completed
in parallel bars
the medial wall and brim of the socket should contain all of the ____ tissues
adductor
the posterior wall of the socket should contain (3)
ischial tub
pubic ramus
portion of glute max
the lateral wall of the socket should have relief wall over the….
greater trochanter
allows for snug fit against glute med
transpelvic and hip disarticulations are primarily due to what?
cancer
in hip disarticulations, a 3D hip joint is used with what prosthesis
C-leg
how do amputees assist with hip flexion during gait?
lumbar posterior tilt
when checking AKA prosthetic fit, the medial wall and brim should contain all of the….
medial adductor tissues
when checking AKA prosthetic fit, the posterior wall should contain the….
ischial tub, public ramus, and a portion of glute max.
