Topic 7: Summaries
Above Knee Socket
Quadrilateral, Ischial Containment, Sub ischial socket (less common)
Quadrilateral
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Uses opposing forces to hold residual limb in position
Good for lower levels of activity
Good for longer residual limbs
Main weight is on the sit bone (ledge built in)
Ischial containment
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Socket contains the ischium and supports the ischum and ramus medially as well as holding
femur in position
Bony lock gives greater control
o Good for more active
o Good control means more stability so good for hip weakness
Good for short, fleshy residual limbs
No main weight bearing point
Suspension methods (AK)
Suction
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Socket and suspension are one
Comfortable
More cosmetic
Bad for volume fluctuation
Good for long, unscarred stumps
No liners needed, therefore more lightweight
Pulls limb into socket and then closes valve to lock in
Elastic suspension belts
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Highly adjustable for volume fluctuation
Can be used for increased rotational control
Easy to don and doff
Silicone self-suspension (ICEROSS?)
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Roll on liner and pin to lock in
High level of suspension therefore good for active patients
More cushioning therefore more comfortable
Difficult to put on
Best suspension method
Knee
Single axis free swing knee
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Swing control: none
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Stance control: musculature only
cheap
Manual locking knee
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Swing phase control:
Stance Phase control: manually locked
Most stable
Used for short residual limb
Used for poor hip strength/control
Knee is locked during gait and unlocked to sit
Causes gait pathologies in order to walk
Used for less active
Single axis constant friction knee
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Swing Phase control: constant friction
Stance Phase control: can be added
Knees bend freely
Muscles must control stability
Used for children or excelled musculature adults
Single speed walking
Friction on knee can be adjusted
Very durable and easy to maintain/repair
Bad for older patient and unstable ground as risk of bucling
Hydraulic or pneumatic control can be added to allow for variable speed
Weight activated stance control knee
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Single axis constant friction knee^ as above, but with a braking mechanism to prevent knee
buckling
Cannot bend knee with weight (sitting issue)
Good for low walking only
Polycentric knees
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Swing phase control: Can add mechanical friction or hydraulic resistance
Stability in all phases of gait
Allows for swing clearance
Good for those who need more stability but can walk at moderate to faster pace
Good for very long tumps
Hydraulic and Pneumatic Knees
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Swing phase control: Hydraulic and Pneumatic
Stance phase control: Hydraulic and Pneumatic
Added to mechanical or computerised knees
Heavier and more expensive than mechanical but lighter and less expensive than
computerised
Good for stairs, sitting
Varied gait
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Hydraulic is best for active individuals
Computerised Knee
1. Patients who can control coluntarily the stability of the prothesis under all conditions
a. Basic single axis free swinging knee
2. Patients unable to control the knee at all
a. Manual locking
3. Feeble patients or recent amputees with slow walking speeds or one speed
a. Friction brake control
b. Polycentric friction breake
4. Faster walking patients
a. Pneumatic or hydraulic knees
i. Varying levels of this depending on level of activity
5. Outdoor or community or vocational ambulators
a. Pneumatic or hydraulic