Prosthetic Components BK & AK Flashcards
What is a preparatory vs. definitive prosthesis?
- Preparatory Prosthesis: Initial prosthesis for temporary use during early gait training, expected to be replaced within 3-9 months due to residual limb changes.
- Definitive Prosthesis: A long-term prosthesis providing comfort, fit, cosmetic appeal, and durability, fitted once the residual limb stabilizes.
What is a check socket?
A transparent socket used to assess prosthetic fit.
Describe pistoning in prosthetic use.
Movement of the residual limb up and down within the socket while walking.
What are the key differences between PTB and TSB sockets?
- Patellar Tendon Bearing (PTB) focuses weight-bearing on specific areas,
- Total Surface Bearing (TSB): distributes pressure evenly across the limb.
Explain the function of gel liners in prosthetics.
Gel liners provide…
- protection against shear and pressure
- used to enhance comfort and suspension
suction vs. vacuum suspension ?
a) Suction Suspension: mainly used by AK level amputees
- designed to provide suspension by negative pressure vacuuming
- forcing air out of the socket through a one-way valve when donning and using the prosthesis
- soft tissues of the residual limb must precisely fit the contours of the socket.
- works well for those whose residual limbs maintain a constant shape and size.
b) Vacuum Suspension: A pump and exhaust valve remove virtually all air between the socket and the liner as you wear them.
- requires external sleeve to create an air tight barrier around the top edge of the socket.
- the system regulates the vacuum level within a defined range.
- Vacuum enhances how well your socket adheres to your limb = reduces shear, regulates residual-limb volume changes and improves circulation in your limb.
- vacuum is the best form of suspension but doesn’t work for all amputees with excessive soft tissue or irregular shaped residual limbs.
What is a TES belt?
A total elastic suspension belt used for auxiliary suspension in transtibial prosthetics.
What is the function of a stance control knee?
Provides stability during missteps or uneven surfaces by locking the knee during stance phase.
How do microprocessor knees adjust to gait?
They perform real-time analysis, making hydraulic adjustments to ensure stability, security, and efficiency.
What is a SACH foot and for which functional level is it used?
A solid ankle cushion heel foot for low K levels, providing plantar flexion moment at heel strike.
Describe an energy-storing foot.
A foot that absorbs energy during mid-stance and releases it at toe-off, improving gait efficiency.
What are the advantages of dynamic pylons?
They store energy during mid-stance, releasing it to assist with toe clearance and limb advancement.
What are the signs of wearing too few socks with a prosthesis?
Pressure on the patella, end of limb, redness over bony areas, and socket movement or instability.
What is the function of a locking liner in prosthetics?
Locks the prosthesis in place using a pin-lock mechanism, ensuring secure suspension.
How do hydraulic swing-phase knees enhance gait?
They provide resistance to flexion/extension during swing phase, allowing variable cadence.
What is the purpose of vertical shock and torque absorbers?
They reduce impact at heel strike and rotational shear forces within the socket.
What is the difference between single-axis and polycentric knee joints?
Single-axis is simpler and less stable, while polycentric offers greater stability and easier swing initiation.
Describe the SAFE foot and its functional level.
A flexible keel foot that allows triplanar movement, suitable for K2 functional level, providing mid-stance stability.
What are the advantages and disadvantages of suction suspension?
- Advantages include better socket fit and circulation.
- Disadvantages are difficulty with volume fluctuations and fit precision.
What is an elevated vacuum system?
A system that maintains constant limb volume by pulling air out of the socket, improving suspension and proprioception.
How do prosthetic socks manage limb volume?
By varying ply thickness, allowing adjustment for residual limb size changes and comfort.
What is the function of the quadrilateral socket?
Supports weight through the ischium and gluteal muscles, providing M-L stability.
Describe the MAS socket.
The Marlo Anatomical Socket offers increased range of motion and M-L control, with weight-bearing through the ischial-ramal area.
What is the purpose of the sub-ischial socket design?
Enhances M-L and A-P stability, reduces rotation, and encourages muscle contraction during gait.
