Prosthetic Sockets, Knees & Foot Types Flashcards
What determines the prosthetic Rx?
- Functional K Level
- Physical Concerns (level of amputation, disease pathology, BW, skin integ)
- Vocational and leisure activities
- Cognitive Skills
- Home environment
- Insurance
How many K Levels are there?
5 Levels
Level 0-4
Describe Level 0
no ability or potential for weight bearing or transfer
Describe Level 1
ability or potential to transfer and ambulate within household with an AD
Describe Level 2
Community ambulator with the ability or potential to traverse minor environmental barriers, fixed cadence
Describe Level 3
Community ambulator with the ability or potential to traverse all environmental barriers with a variable cadence
Describe Level 4
the ability or potential for prosthetic ambulation that exceeds basic skills, exhibiting high impact stress, or energy levels. Typical of the demands of a child, active adult or athlete.
What are physical concerns for amputation?
Amputation length Weight restrictions on components Vocational and Leisure activities Skin integrity Peripheral neuropathy/hand strength Disease Pathologies
What are some cognitive realities for amputees
- Ability to follow and remember instructions
- Pt compliance
- Ability to get on/off prosthesis independently
- Adjust prosthetic fit
- Is there reliable ‘help’ at home
What is insurance coverage like for amputees?
- Payers typically follow Medicare payment guidelines
- Detailed Rx and LOM needed
- Authorization required
- Replacement: physical changes, medical necessity, damage, change in K level
- Restrictions on ‘experimental’ technology commonplace
What costs more: transtibial or transfemoral?
Transfemoral $10-60,000 compared to transtibial ($7-14,000)
Our thought is more joints to replace with transfemoral
Fitting of a prosthesis
Start at a “bench alignment” to a “personal alignment”
Describe socket design, socket interface, and suspension
Socket Design: muscle cotouring and total contact
Socket interface: socks, gel liners
Suspension: sleeve, suction, pin locks, belts
What are the principles of socket design
- Contour, relief and support for functioning muscles
- Stabilize Skeletal Structure
- Position Muscles to optimize strength
- Minimize applied pressures to neurovascular structures
- Distribute forces within socket over the entire limb
Would you rather bear weight on bone or muscular structure
Muscular structure, tendon is what you want to bear weight on.
*Think when you sit, your ischial tubes are sore, so you don’t want to put a lot of pressure on a bone.
2 Types of Transtibial socket designs
- Patellar Tendon Bearing
2. Total Surface Bearing (newer)
Describe Patella Tendon Bearing socket (PTB)
- older style
- WB concentrated in specific areas (patellar tendon, medial tib flare, gastroc)
- relief modified into cast for boney anatomy
- Triangular shape to socket
- Excessive pressure in popliteal fossa or patella tendon
What are the specific WB areas concentrated in with Patellar Tendn Bearing
Patellar tendon
Medial tibial flare
Gastrocnemius
Describe Total Surface Bearing (TSB)
- Pressure distributed over ENTIRE limb surface
- Total contact with socket while every unit area is under compression
- Best incorporated with Suction Suspension or elevated vacuum
- Global volume reduction of residual limb
- Often used with gell liner interface
PTB vs. TSB vs. Hydrostatic
Really wish we could add pictures
PTB: pressure in only one section
TSB: full coverage
Hydrostatic: pressure from the inside going out
Describe Hydrostatic Design Sockets
- Also considered TSB but utilized compression chambers to achieve uniform fit
- Fluids in chambers utilized Pascal law
- Use silicon suction suspension sleeve
What is a Check Socket or Diagnostic Socket?
A transparent socket used to aid in assessing prosthetic fit.
What is a Definitive Prosthesis?
A prosthesis that is intended for long term usage, comfort, fit, cosmetic appeal and durability. Usually fit once the residual limb stabilizes.
What is Pistoning?
Refers to the residual limb moving up and down within the socket while walking.
What is a Preparatory Prosthesis?
Initial prosthesis that may or may not include definitive components. It is intended for temporary use to allow the patient to begin therapy for gait training. It is expected that it will need to be replaced within 3-9 months due to changes in the residual limb.
What is a Socket liner?
A soft interface used between the hard socket and residual limb. These can be made of various types of gel, socks or soft foams.
What is a Suspension Sleeve?
An elastic tube made of varying materials that is first pulled over the outside of the prosthesis and then rolled up onto the thigh once the prosthesis is put on.
What is a C-Leg?
The Otto Bock C-Leg features a swing & stance phase control system that senses weight bearing & positioning to provide the knee’s microprocessor info about the amputee’s gait, thus promoting smoother ambulation. The outer shell houses a hydraulic cylinder, microchip, & rechargeable battery.
What is an energy storing foot?
A prosthetic foot designed with a flexible heel, which stores energy when weight is
applied to it & releases this energy when weight is transferred to the other foot.
What is an Ischial containment socket?
In some amputation cases, usually those of the HP or HD, this socket is used to support the Ischium.
What is a multiaxis foot?
The multi-rotational axis allows for inversion and eversion of the foot, and it is effective for walking on uneven surfaces.
What is a pylon?
A rigid member, usually tubular, between the socket or knee unit and the foot that provides a weight bearing, shock-absorbing support shaft for the prosthesis.
What is a suction socket?
This socket is designed to provide suspension by means of negative pressure vacuuming. (achieved by forcing air out of the socket through a one-way valve when donning & using the prosthesis). In order for this type of socket to work properly, the soft tissues of the residual limb must precisely fit the contours of the socket. It is mainly used by AK amputees & work very well for those whose residual limbs maintain a constant shape & size.
