4: Ankle and Foot Components

Question 1

What are the three main components of a prosthetic?

Answer 1

Socket, pylon, foot

Question 2

What are the two types of prosthetic feet?

Answer 2

Non-articulating or articulating

Question 3

What is the function of a prosthetic foot?

Answer 3

Serves as a shock absorber and provides a stable weight-bearing surface

Question 4

What type of foot is a SACH foot, and what K level is is indicated for?

Answer 4

Non-articulating, K1

Question 5

What type of foot is a single axis foot, and what K level is is indicated for?

Answer 5

Articulating, K1

Question 6

What type of foot is a multi-axis foot, and what K level is is indicated for?

Answer 6

Articulating, K2

Question 7

What type of foot is a dynamic response or energy storing foot, and what K level is it indicated for?

Answer 7

Articulating, K3

Question 8

What type of foot is a multi-axial dynamic response foot, and what K level is is indicated for?

Answer 8

Articulating, K3

Question 9

What type of foot is a microprocessor, and what K level is it indicated for?

Answer 9

Articulating, K4

Question 10

What does SACH stand for?

Answer 10

Solid ankle cushioned heel

Question 11

Describe a SACH foot

Answer 11

Light weight, inexpensive, wooden or metal keel that extends MTP joints, rubber heel to allow for shock absorption

Question 12

What motion is allowed with a SACH foot?

Answer 12

Plantarflexion at loading response

Question 13

What is the function of the rubber heel wedge of the SACH foot?

Answer 13

Mimics ankle action by compressing under load during the early part of stance phase

Question 14

Describe the keel of the SACH foot

Answer 14

Rigid, which provides midstance stability but little lateral movement

Question 15

Describe the ankle joint of the SACH foot

Answer 15

Allows the foot to move up and down and enhances knee stability

Question 16

What must the wearer of a SACH foot do, and what device would require less effort in comparison?

Answer 16

Must actively control the prosthesis to prevent the knee from buckling. Single-axis will require less effort

Question 17

What type of foot is shown in the image?

Answer 17

SACH

Question 18

If stability is a concern for a SACH foot, what other device may be more appropriate?

Answer 18

Single-axis

Question 19

What planes does motion occur in with a single-axis foot?

Answer 19

Some sagittal that is controlled by interchangeable anterior and posterior bumpers. No transverse or frontal plane movement

Question 20

How much sagittal plane motion is allowed with a single-axis foot?

Answer 20

Dorsiflexion 5-7 degrees
Plantarflexion 15 degrees

Question 21

What are disadvantages of the single axis foot?

Answer 21

Heavier and requires more maintenance than SACH

Question 22

What type of foot is shown in the image?

Answer 22

Single-axis

Question 23

What type of foot is shown in the image?

Answer 23

Multi-axis

Question 24

What motions are allowed with a multi-axis foot?

Answer 24

Dorsiflexion and plantarflexion. Also allows for some pronation and supination to cope with uneven terrain

Question 25

What are disadvantages of a multi-axis foot?

Answer 25

More expensive and heavier

Question 26

What is a benefit of the multi-axis foot?

Answer 26

Added ankle motion absorbs some of the stress of walking, which will help protect the skin and the prosthesis from wear and tear

Question 27

Describe the dynamic response/energy storage foot

Answer 27

Contains a leaf spring that stores energy during rocker and the releases

Question 28

What happens with a dynamic response/energy storage foot as cadence or activity increases?

Answer 28

Dynamic response increases and results in greater energy return

Question 29

What device is shown in the image?

Answer 29

Dynamic response/energy storage

Question 30

What pt population will benefit from a multi-axis dynamic response foot?

Answer 30

People who have more active lifestyles that can vary their walking speed, change directions quickly, and walk long distances

Question 31

What does a multi-axis dynamic response foot allow for?

Answer 31

More normal ROM and a more symmetric gait pattern

Question 32

What is the function of a split-toe design?

Answer 32

Further increases stability by mimicking the inversion and eversion movements of a human ankle and foot

Question 33

What effect can the dynamic response foot have on the intact limb?

Answer 33

Reduce impact forces and stress

Question 34

Describe the microprocessor foot

Answer 34

Able to identify slopes and stairs after the first step. Automatically provides dorsiflexion during swing phase. Automatic plantarflexion allow for natural appearance when seated

Question 35

How will a pt with a microprocessor foot get up from a chair?

Answer 35

Active ankle motion allows then to tuck both feet behind their knees when getting up

Question 36

What are advantages of a microprocessor foot?

Answer 36

Provides push off, increased ability to self-select gait speed, 9.9% less energy expenditure

Question 37

What are disadvantages of a microprocessor foot?

Answer 37

Poor battery life, heavy, expensive

Question 38

What should you consider when choosing an appropriate foot?

Answer 38

Activity level, K level 0-4, ability to reach a higher level, cosmetic appearance, ability to resist moisture, heel height, recreation, maintenance