Prosthetic Components and Design

Question 1

trim line

Answer 1

edges of the prosthetic socket

Question 2

definitive prosthesis

Answer 2

the end product produced by the prosthetist

Question 3

what is suspension? name the 5 main types

Answer 3

how the device is attached to the residual limb
suspension belts/cuffs, lanyard, pin-lock, suction and elevated vacuum

Question 4

bench alignment

Answer 4

relationship among components set by prosthetist before customizations are made

Question 5

What are the main 2 socket designs for transtibial amputations?

Answer 5

patellar tendon-bearing socket and total surface-bearing socket

Question 6

Describe weight distribution of a patellar tendon-bearing socket.

Answer 6

it loads the patellar tendon and medial tibial flare (thus off-loading the fibular head and tender boney area. It also has a low post trim line for hamstring tendons.

Question 7

Describe weight distribution of a total surface-bearing socket

Answer 7

more natural -feeling distribution of weight over entire residual limb to reduce shear forces. difficult to make correctly though

Question 8

what are the 2 main types of transfemoral sockets?

Answer 8

quadrilateral and ischial containment

Question 9

Describe structure of a quadrilateral socket.

Answer 9

four walls containing the thigh with the highest in the front vs back, posterior shelf for the glutes

Question 10

Describe structure of a ischial containment socket.

Answer 10

covers ischial tuberosity with a wider A>P than M>L to resist extra femoral ABD, higher medial and posterior wall

Question 11

what are the pros and cons of lanyard suspension?

Answer 11

pros: security, constant alignment, and doesn’t take up space at the bottom of the socket

cons: visible

Question 12

what are the pros and cons of pin-lock suspension?

Answer 12

pros: secure, mechanical connection
cons: potential suction effect, difficult to align for deaf and blind, shuttle lock takes up socket space

Question 13

what are the pros and cons of suction suspension? (think socket w/ rings)

Answer 13

pros: good fo rblood flow, very good suspension esp for fluctuating blood volume

cons: wear out liners quickly

Question 14

what are the pros and cons of elevated vacuum suspension?

Answer 14

pros: comfortable and enables vol fluctuations
cons: heavy, must be charged, heavy coponent that takes up socket space

Question 15

what are the 3 types of liners and what suspension types do they work best w/

Answer 15

silicone- pin-lock (soft, pressure-resist)
polyurethane-vacuum and suction (pressure absorption)
copolymer-total surface bearing (low activity)

Question 16

Are socks the same as liner? where should they be worn?

Answer 16

NO, between the liner and socket to accommodate extra space

Question 17

what is the order for applying components>prosthetic?

Answer 17

liner>sock>socket?prosthetic

Question 18

what are the 4 types of prosthetic feet and the K levels they are associated with?

Answer 18

K1- SACH
K2:Single axis or multi axial
K3: Multi-axial
K4: hydraulic, multi-axial or crossover

Question 19

Describe the single-axis, cushioned heel (SACH) foot

Answer 19

still and stable with limited energy return (req more effort>)

Question 20

Describe the single-axis foot.

Answer 20

articulation joint for PF/DF
quick PF enable foot flat in initial contact and is good for TFA ** and user confidence

Question 21

Describe the multi-axial foot.

Answer 21

enables PF/DF/INV/EV, split toe for uneven terrain, functional w/ good energy return

Question 22

What is the function of the keel and what are the upstream effects it has on gait?

Answer 22

can be rigid flexible or dynamic to provide necessary stability. Impacts toe lever, heel rise/toe break of terminal stance, dictates knee flexion/stability

Question 23

what are the 5 types of prosthetic knees?

Answer 23

polycentric, manual locking, pneumatic, hydraulic, micropressor

Question 24

How do single axis and polycentric knees affect postural alignment? What does this require of the body?

Answer 24

It encourages GRFV to be anterior to the knee»body compensates with hip extension

Question 25

Describe the manual locking knee.

Answer 25

it’s the most stable stance control knee but sacrifices knee flexion if not unlocked

Question 26

describe hydraulic and pneumatic knees.

Answer 26

They use friction to control swing speed and adjust to user’s gait speed.

Question 27

what are the benefits of hydraulic and pneumatic knees.

Answer 27

control on uneven surfaces
variable cadence and gait speed
mimics normal gait

Question 28

describe the MOA and function of microprocessor knees

Answer 28

sensors measure joint angles, cadence,etc to provide stable and responsive knees for stance and swing phase control

Question 29

what are the benefits of microprocessor knees

Answer 29

stumble recovery,stairs, power