Biomechanics of prosthetic use Flashcards
define alignment
generally orientation of where foot is in relation to the socket (can be reverse)
define bench alignment
starting point for dynamic alignment; completed w/o prosthesis on the patient, the device should be balanced enough to sit unsupported on a “bench”
define checkout (aka dynamic alignment)
dynamic adjustments for final safety and functionality check
what are the 4 alignment goals for gait?
- heel strike @ IC
2.adequate single-limb stability during stance - smooth forward progression in late stance
- toe clearance during swing phase
can you list the common pain complaints of transtibial patients?
head of fibula due to nerves in this area
patella moving fwd in socket>WBing in bone
pressure sores at distal end of residual limb
where are our plumb line marks? Is this the same as “alignment”?
greater trochanter, knee, and ankle; no
where SHOULD TT pts bear weight for patellar bearing socket? (4 spots)
patellar tendon
pretibials+ med/lat tibial flares
posterior distal residual limb
lateral shaft of fibula
Describe TT static alignment for frontal plane.
even iliac crests
= supracondylar compression
comfortable socket
central plumbline w/ vertical tube
flat feet w/ even weight
5 deg abd for natural varus
what are some potential issues that could arise from a foot that is too inset for TT patients?
Pt report pain
proximally: medial, distally: lateral
lateral instability
Therapist sees:
breakdown in pain areas
lateral gapping
what are some potential issues that could arise from a foot that is too outset for TT patients?
Pt report pain
proximally: lateral, distally: medial
medial instability
Therapist sees:
breakdown in pain areas
medial gapping
how would one correct a TT inset foot?
translate medially
how would one correct a TT outset foot?
translate laterally
why do we want to see 5 deg of flexion built into our TT sockets?
it elongates the quads a little to provide some tension during loading response to increase WBing potential , ext during swing phase
in the sagittal plane for the TT socket, where on the foot should the plumb line fall?
posterior 2/3
what are some potential issues that could arise from a foot that is too anterior for TT patients?
Pt:
proximal pain: ant
distal pain: post
Therapist:
foot too far fwd, breakdown in pain areas, difficulty w/ flexion
what are some potential issues that could arise from a foot that is too posterior for TT patients?
Pt:
proximal pain: post
distal pain:ant
Therapist:
foot too far back, breakdown in pain areas, hyperflexion in stance
a low heel will artificially___the knee, while a high heel will___it.
extend; flex
what are 2 main goals of transfemoral prosthetics?
minimize rotation and provide frontal and sagittal plane stability
how is rotation minimized in a transfemoral prosthetic?
good boney capture
posterior pelvic tilt for pt to “sit” on during WBing
adductor tendon capture in medial groove
how are frontal and sagittal plane stability achieved for TF pts
inclined and adducted lateral wall (greater troch contact)
5 deg flexion bild into socket>sitting on rim
GRFV ant to knee during stance
where should TF pts bear weight in their prosthetic?
Quad socket: Ischial tuberosity
Ischial Containment: most pressure tol areas
Describe TF static alignment for frontal plane.
knee axis is horizontal
tube is vertical
foot w/ required heel height is flat on the floor
what are some potential issues that could arise from a foot that is too inset for TF patients?
pt: pain@ proximal:medial and distal lateral
PT: foot too medial to socket, pressure sore @ listed areas
what are some potential issues that could arise from a foot that is too outset for TF patients?
pt: pain@ proximal:lateral and distal: medial
PT: foot too lateral to socket, pressure sore @ listed areas
How would we correct a TF with an outset foot?
translate laterally
How would we correct a TF with an inset foot?
translate medially
Describe TT static alignment for sagittal plane.
built in 5 deg of flexion
trochanter-knee-ankle line 10-15deg from knee axis
vertical tube
foot is flat
why is it important to have 5 deg of flexion in a TF socket?
increase L-T relationship enhances glute firing
avoids hyperlordosis
what problem might a TF pt have if their foot is too posterior (socket is too far anterior?)
difficulty extending during swing
what problem might a TF pt have if their foot is too far anterior (socket posterior)?
knee that is prone to buckling/hyperflexion
what are the 10 markers for a static checkout?
flat feet, comfortable socket, adequate suspension, level boney landmarks, tube is vertical (pylon), stable knee
normal tissue rolls, gapping, distal contact in residual limb, shoulder width heel space (10cm)
as a PT, ___ can tell you volumes about improper alignment.
frequent skin checks (every visit up to 18 months pos-op)
