4: Ankle and Foot Components Flashcards
What are the three main components of a prosthetic?
Socket, pylon, foot
What are the two types of prosthetic feet?
Non-articulating or articulating
What is the function of a prosthetic foot?
Serves as a shock absorber and provides a stable weight-bearing surface
What type of foot is a SACH foot, and what K level is is indicated for?
Non-articulating, K1
What type of foot is a single axis foot, and what K level is is indicated for?
Articulating, K1
What type of foot is a multi-axis foot, and what K level is is indicated for?
Articulating, K2
What type of foot is a dynamic response or energy storing foot, and what K level is it indicated for?
Articulating, K3
What type of foot is a multi-axial dynamic response foot, and what K level is is indicated for?
Articulating, K3
What type of foot is a microprocessor, and what K level is it indicated for?
Articulating, K4
What does SACH stand for?
Solid ankle cushioned heel
Describe a SACH foot
Light weight, inexpensive, wooden or metal keel that extends MTP joints, rubber heel to allow for shock absorption
What motion is allowed with a SACH foot?
Plantarflexion at loading response
What is the function of the rubber heel wedge of the SACH foot?
Mimics ankle action by compressing under load during the early part of stance phase
Describe the keel of the SACH foot
Rigid, which provides midstance stability but little lateral movement
Describe the ankle joint of the SACH foot
Allows the foot to move up and down and enhances knee stability
What must the wearer of a SACH foot do, and what device would require less effort in comparison?
Must actively control the prosthesis to prevent the knee from buckling. Single-axis will require less effort
What type of foot is shown in the image?
SACH
If stability is a concern for a SACH foot, what other device may be more appropriate?
Single-axis
What planes does motion occur in with a single-axis foot?
Some sagittal that is controlled by interchangeable anterior and posterior bumpers. No transverse or frontal plane movement
How much sagittal plane motion is allowed with a single-axis foot?
Dorsiflexion 5-7 degrees
Plantarflexion 15 degrees
What are disadvantages of the single axis foot?
Heavier and requires more maintenance than SACH
What type of foot is shown in the image?
Single-axis
What type of foot is shown in the image?
Multi-axis
What motions are allowed with a multi-axis foot?
Dorsiflexion and plantarflexion. Also allows for some pronation and supination to cope with uneven terrain
What are disadvantages of a multi-axis foot?
More expensive and heavier
What is a benefit of the multi-axis foot?
Added ankle motion absorbs some of the stress of walking, which will help protect the skin and the prosthesis from wear and tear
Describe the dynamic response/energy storage foot
Contains a leaf spring that stores energy during rocker and the releases
What happens with a dynamic response/energy storage foot as cadence or activity increases?
Dynamic response increases and results in greater energy return
What device is shown in the image?
Dynamic response/energy storage
What pt population will benefit from a multi-axis dynamic response foot?
People who have more active lifestyles that can vary their walking speed, change directions quickly, and walk long distances
What does a multi-axis dynamic response foot allow for?
More normal ROM and a more symmetric gait pattern
What is the function of a split-toe design?
Further increases stability by mimicking the inversion and eversion movements of a human ankle and foot
What effect can the dynamic response foot have on the intact limb?
Reduce impact forces and stress
Describe the microprocessor foot
Able to identify slopes and stairs after the first step. Automatically provides dorsiflexion during swing phase. Automatic plantarflexion allow for natural appearance when seated
How will a pt with a microprocessor foot get up from a chair?
Active ankle motion allows then to tuck both feet behind their knees when getting up
What are advantages of a microprocessor foot?
Provides push off, increased ability to self-select gait speed, 9.9% less energy expenditure
What are disadvantages of a microprocessor foot?
Poor battery life, heavy, expensive
What should you consider when choosing an appropriate foot?
Activity level, K level 0-4, ability to reach a higher level, cosmetic appearance, ability to resist moisture, heel height, recreation, maintenance