Biomechanics of prosthetic use

Question 1

define alignment

Answer 1

generally orientation of where foot is in relation to the socket (can be reverse)

Question 2

define bench alignment

Answer 2

starting point for dynamic alignment; completed w/o prosthesis on the patient, the device should be balanced enough to sit unsupported on a “bench”

Question 3

define checkout (aka dynamic alignment)

Answer 3

dynamic adjustments for final safety and functionality check

Question 4

what are the 4 alignment goals for gait?

Answer 4

1. heel strike @ IC
   2.adequate single-limb stability during stance
2. smooth forward progression in late stance
3. toe clearance during swing phase

Question 5

can you list the common pain complaints of transtibial patients?

Answer 5

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

Question 6

where are our plumb line marks? Is this the same as “alignment”?

Answer 6

greater trochanter, knee, and ankle; no

Question 7

where SHOULD TT pts bear weight for patellar bearing socket? (4 spots)

Answer 7

patellar tendon
pretibials+ med/lat tibial flares
posterior distal residual limb
lateral shaft of fibula

Question 8

Describe TT static alignment for frontal plane.

Answer 8

even iliac crests
= supracondylar compression
comfortable socket
central plumbline w/ vertical tube
flat feet w/ even weight
5 deg abd for natural varus

Question 9

what are some potential issues that could arise from a foot that is too inset for TT patients?

Answer 9

Pt report pain
proximally: medial, distally: lateral
lateral instability
Therapist sees:
breakdown in pain areas
lateral gapping

Question 10

what are some potential issues that could arise from a foot that is too outset for TT patients?

Answer 10

Pt report pain
proximally: lateral, distally: medial
medial instability
Therapist sees:
breakdown in pain areas
medial gapping

Question 11

how would one correct a TT inset foot?

Answer 11

translate medially

Question 12

how would one correct a TT outset foot?

Answer 12

translate laterally

Question 13

why do we want to see 5 deg of flexion built into our TT sockets?

Answer 13

it elongates the quads a little to provide some tension during loading response to increase WBing potential , ext during swing phase

Question 14

in the sagittal plane for the TT socket, where on the foot should the plumb line fall?

Answer 14

posterior 2/3

Question 15

what are some potential issues that could arise from a foot that is too anterior for TT patients?

Answer 15

Pt:
proximal pain: ant
distal pain: post

Therapist:
foot too far fwd, breakdown in pain areas, difficulty w/ flexion

Question 16

what are some potential issues that could arise from a foot that is too posterior for TT patients?

Answer 16

Pt:
proximal pain: post
distal pain:ant

Therapist:
foot too far back, breakdown in pain areas, hyperflexion in stance

Question 17

a low heel will artificially___the knee, while a high heel will___it.

Answer 17

extend; flex

Question 18

what are 2 main goals of transfemoral prosthetics?

Answer 18

minimize rotation and provide frontal and sagittal plane stability

Question 19

how is rotation minimized in a transfemoral prosthetic?

Answer 19

good boney capture
posterior pelvic tilt for pt to “sit” on during WBing
adductor tendon capture in medial groove

Question 20

how are frontal and sagittal plane stability achieved for TF pts

Answer 20

inclined and adducted lateral wall (greater troch contact)
5 deg flexion bild into socket>sitting on rim
GRFV ant to knee during stance

Question 21

where should TF pts bear weight in their prosthetic?

Answer 21

Quad socket: Ischial tuberosity
Ischial Containment: most pressure tol areas

Question 22

Describe TF static alignment for frontal plane.

Answer 22

knee axis is horizontal
tube is vertical
foot w/ required heel height is flat on the floor

Question 23

what are some potential issues that could arise from a foot that is too inset for TF patients?

Answer 23

pt: pain@ proximal:medial and distal lateral

PT: foot too medial to socket, pressure sore @ listed areas

Question 24

what are some potential issues that could arise from a foot that is too outset for TF patients?

Answer 24

pt: pain@ proximal:lateral and distal: medial

PT: foot too lateral to socket, pressure sore @ listed areas

Question 25

How would we correct a TF with an outset foot?

Answer 25

translate laterally

Question 26

How would we correct a TF with an inset foot?

Answer 26

translate medially

Question 27

Describe TT static alignment for sagittal plane.

Answer 27

built in 5 deg of flexion
trochanter-knee-ankle line 10-15deg from knee axis
vertical tube
foot is flat

Question 28

why is it important to have 5 deg of flexion in a TF socket?

Answer 28

increase L-T relationship enhances glute firing
avoids hyperlordosis

Question 29

what problem might a TF pt have if their foot is too posterior (socket is too far anterior?)

Answer 29

difficulty extending during swing

Question 30

what problem might a TF pt have if their foot is too far anterior (socket posterior)?

Answer 30

knee that is prone to buckling/hyperflexion

Question 31

what are the 10 markers for a static checkout?

Answer 31

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)

Question 32

as a PT, ___ can tell you volumes about improper alignment.

Answer 32

frequent skin checks (every visit up to 18 months pos-op)