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Above Knee Prosthesis

Socket

1Socket inner face, fits into hard socket.
2Hard plastic coupled with socks
3Hard plastic coupled with gel
4Hard plastic w/ suction skin fit
5Flexible inner liner coupled with socks
6Flexible inner liner coupled with Gel
7Flexible inner liner w/ suction skin fit

Suspension

Holds prosthetic to body

1 Silesian Belt : usually belt raps around patients waist attached to prosthesis
2 Gel liner w/ pin or Lanyard strap : usually Silicone or Urethane rolls on skin holding by a suction to the skin, then a mechanical lock occurs between the exterior pin or strap on liner to the socket.
3 Gel liner w/ Suction Ring & valve : usually Silicone or Urethane rolls on skin holding by a suction to the skin, ring will evacuate air out of socket via one way valve.
4 Pelvic Belt w/ Hip Band : Usually coupled with a metal band that sits on hip attached to leather belt that goes around waist.
5 TES Belt : Removable Neoprene belt pulled onto socket raps around waist.
6 Total Suction : This type permits air to be evacuated from socket via a valve, socket is held to residual limb by outside air pressure, often belts and straps can be eliminated.

Prosthetic Knee

Can come in many shapes and sizes.

They are broken down into two types:

Single Axis : Single knee joint, also can be constructed with Stance control (the ability of the knee to lock preventing it from buckling when weight is applied on it).

Polycentric : More than one knee joint, primarily used on Long Above Knee amputations for a lower profile design.

Single Axis & Polycentric knee types :

1Manual Lock : Will stay locked until manually released.
2Constant Friction : Knee joint has capability to free swing, speed is set by a friction screw not a variable speed but a constant speed determined by amount of friction applied
3Fluid Control : Swing of knee controlled by a Hydraulic (fluid) or Pneumatic (air) unit giving prosthesis Cadence Variability (ability to change speeds according to amputees activity)
4Microprocessor Controlled : Usually a fluid controlled knee coupled with a microprocessor to control the rate the fluid reacts depended on the step of the patient. Usually has stance (knee can lock up) capabilities controlled by the microprocessor unit in knee.

Pylon

The rigid shaft or tube below prosthetic knee controls the length and attaches knee to the foot.


Prosthetic Foot

Below are general types with a brief description and function.

1 SACH : Hard internal keel that has no movement with firm a foam cosmesis.
2 Elastic or Flexible Keel : Simulates ankle motion with out true ankle joint.
3 Single Axis Foot : Ankle motion in one plane going forward and backward, can be constructed with various keel types.
4 Multi-axial Foot : Ankle motion in more than one plane, can be constructed with various keel types.
5 Energy Responsive Foot : Keel is made of composite materials that when loaded by body weight can give return from heel strike to toe off. A good example is how a diving board reacts when someone jumps on, it will load then spring off. This type of foot can be constructed to simulate ankle motion without a true ankle joint or it can be incorporated into a Single Axis or Multi-axial Foot.