Prosthetic Components

Question 1

define keel

Answer 1

supportive structure of the prosthetic foot that provides stability to the user

*essentially the new amputee’s foot length

Question 2

how is the length of the keel impactful on upstream structures?

Answer 2

1. larger toe lever or longer keel makes it difficult for user to initate gait
2. heel rise/toe break
3. the position of the keel relative to the socket can impact knee flexion and stability

Question 3

define toe lever

Answer 3

the distance from the center of the socket to the end of the keel

Question 4

how does the length of the keel influence gait?

Answer 4

1. too short → leads to knee instability in late mid stance
2. too long → like clown shoes
   
   • difficult to progress over foot in midstance and flex knee during late stance
   • pts may have trouble clearing foot or catching toe

Question 5

List several different types of prosthetic knees

Answer 5

1. single axis
2. polycentric
3. manual locking
4. pneumatic
5. hydraulic
6. microprocessor

Question 6

prosthetic knees can influence gait by offering _________ or _________. Some even offer both of these

Answer 6

stance phase control

swing phase control

Question 7

how can a prosthetic knee offer stance phase control?

Answer 7

it keeps the knee from buckling as you progress onto the foot

Question 8

how can a prosthetic knee offer swing phase control?

Answer 8

it will control the speed at which the pylon/everything below the knee swing through during swing phase of gait

Question 9

In order to promote knee stability, the GRFV must be _______ to the knee

Answer 9

anterior

Question 10

which prosthetic knees only provide stance control?

Answer 10

single axis and polycentric

via alignment they promote the GRFV to be anterior to the prosthetic knee to ensure stability during stance

most basic knee types (some can provide swing phase control)

Question 11

what is the benefit of a manual locking knee?

Answer 11

most stable stance control knee

doesn’t allow for knee flexion during swing phase

lock must be open for pt to sit

Question 12

how do hydrualic and pneuamtic knees provide swing phase control?

Answer 12

they dynamically adjust swing speed to the user’s gait speed by friction

Question 13

List several benefits to swing phase control offered by hydraulic and pneumatic knees

Answer 13

1. control on uneven surfaces
2. variable cadence and gait speed
3. mimics normal gait
4. some can build in stance phase control as well by increasing the friction in the cylinder

Question 14

what does a microprocessor knee provide and how does it accomplish those things?

Answer 14

provides both stance and swing phase control

sensors measure joint angles, cadence, etc. to provide the user with a stable knee that is responsive

Question 15

what are the benefits of a microprocessor knee?

Answer 15

1. stumble recovery
2. stairs
3. power