Prosthetics

Question 1

What is a Syme’s disarticulation?

Answer 1

ankle disarticulation

- heel pad preserved and attached to end of tibia for WB

Question 2

Can you weight bear through disarticulations?

Answer 2

yes

Question 3

T/F: Selective loading is made in a prosthetic socket through build ups on tendon-bearing areas.

Answer 3

true

- relief for bony prominences, nerves, tendons

Question 4

What is the terminal device in a lower-extremity prosthetic?

Answer 4

the foot (terminal end that interacts with environment)

Question 5

What motions does a SACH foot limit?

Answer 5

limits sagittal plane motion, specifically PF

- allows small ML motion, transverse motion

Question 6

For a similar foot to the SACH foot but for a more active individual, what would you prescribe?

Answer 6

a SAFE foot: solid ankle flexible endoskeleton

- allows more nonsagittal plan motions

Question 7

What motions does a single-axis foot allow?

Answer 7

sagittal plane motion, with stops

Question 8

Where are sensitive pressure areas of a transtibial amputee?

Answer 8

anterior tibial crest
anterior tibia
fibular head and neck
fibular nerve

Question 9

What are areas that can tolerate pressure in a trans-tibal amputee?

Answer 9

patellar tendon
medial tibial plateau
tibial/fibular shafts

Question 10

Which type of friction would an older adult who is mostly sedentary need for their knee prosthetic?

Answer 10

constant friction
(vs variable friction, used for varying speeds for more active individuals)

Question 11

If the knee center is set too far forward from the TKA line, what will happen at the knee?

Answer 11

knee will be unstable and buckle

Question 12

What does a friction brake in the knee do?

Answer 12

increases friction at midstance to prevent knee flexion, but allows smooth knee motions through rest of gait cycle

Question 13

What is an extension aid in a prosthetic limb?

Answer 13

external elastic strap or internal coiled sprong that assists with TKE during late swing

Question 14

Where is pressure directed in an above-knee prosthetic?

Answer 14

ischial tuberosity
gluteals
lateral sides of residual limb
distal end (can be sensitive though)

Question 15

Why would a patient demonstrate bending towards the prosthetic side during gait?

Answer 15

• shorter prosthetic limb
• hip pain
• weak abductors
• low lateral wall, high medial wall

Question 16

T/F: A long prosthesis may result in an abducted stance.

Answer 16

true

Question 17

T/F: A socket being too big might cause a patient to vault on the other side to bring the prosthetic limb forward.

Answer 17

false: socket to small can cause vaulting, not too big

Question 18

What might cause excessive lumbar lordosis during stance with a prosthetic?

Answer 18

• painful ischial WB
• hip flexion contracture
• weak hip extensors or abs
• insufficient support from anterior or posterior walls
• inadequate socket flexion

Question 19

Why might the knee lock into TKE during terminal swing with a prosthetic?

Answer 19

• pt fearful so excessively hip flexes limb
• insufficient knee friction
• too much tension in knee extension aid

Question 20

Why might there be a heel whip with a prosthetic limb during swing?

Answer 20

excessive rotation in prosthetic
knee bolt rotated
foot malaligned

Question 21

T/F: A patient who favors the sound limb and limits weight bearing time on the prosthetic limb with demonstrate decreased step length on the prosthetic side.

Answer 21

False, shorter step length on sound side since they won’t stay long on the prosthetic limb in stance

Question 22

With a medial thrust in midstance for a TTA, what could potentially be wrong with the prosthesis?

Answer 22

laterally placed foot

Question 23

T/F: A socket being set too far backward can cause premature knee flexion in stance.

Answer 23

false, socket too far forward = premature knee flexion

Question 24

T/F: If the socket for a TTA is aligned to far backward or tilted posteriorly, this can result in inadequate knee flexion.

Answer 24

true

Question 25

A patient reports that they feel like they’re walking uphill with their prosthetic limb. What could be happening?

Answer 25

socket set too far back/lacks sufficient flexion
DF bumper is too stiff causing excess PF
prosthetic foot keel too long

Question 26

An unstable knee unit will result in what gait deviation?

Answer 26

forward flexion during stance

Question 27

Inadequate socket flexion will result in what gait deviation?

Answer 27

excessive lordosis during stance

Question 28

What prosthetic causes can result in a circumducted gait?

Answer 28

long prosthesis
locked knee unit
loose knee friction
inadequate socket suspension
small/loose socket
PF'ed foot

Question 29

With a plantar flexion bumper being too soft, what gait deviation can occur?

Answer 29

foot slap

- can also occur if heel cushion is too soft`

Question 30

What could cause a lateral thrust in mid stance from a prosthetic?

Answer 30

foot inset too medially

Question 31

What can cause premature knee flexion in late stance?

Answer 31

DF bumper too soft
socket set too far forward/excessively flexed
prosthetic foot keel too short
KF contracture

Question 32

Painful ischial weightbearing in a TFA prosthetic can result in what deviation?

Answer 32

excessive lordosis