Prosthe

Residual Limb

* remaining portion of amputated limb
* stump/residum

Excursion

amount of movement or range of motion that the residual limb can achieve

Component

part of prothesis

terminal device

prosthetic equivalent of human hand, dulo

Hinge

* prosthetic component used to assist or replace an anatomic joint

Rigid Hinge

* stiff solid arrow movement
* one plane
* flex/extn

Flexible Hinge

* allows movemnt in multiple planes
* flxn/extn, pron/supn

Socket

* interface b/w residual limb and prosthetic device as a whole
* designed to distribute forces throughout the residual limb

Prosthetic sock

* cotton
* fits residual limb like a sock
* worn b/w socket and liner to account for volume changes (size) in the residual limb

Laminate

* plastic composite usually made with carbon fiber and resin

Gel Liner

* made from silicone gel or similar polymer
* rolls onto the residual limb like a sleeve and creates a suction interface b/w skin and socket

Mechanical

designates a moving component

Passive

cosmesis>function

Heavy Duty

* connotes a prosthetic designed to withstand strong, repetitive forces and rugged conditions
* automotive mechanic, construction worker

Passive System

* cosmetic, but also functions as a stabilizer
* for pts who do not have enough strength or mvmt to control prosthesis, or wears prosthesis only for cosmesis
* replaces limb, not functional

Body-powered system

* uses pt’s own residual limb or body strength and rom to control prosthesis

externally-powered system

* uses outside power source such as a battery to operate prosthesis
* similar to bps

Hybrid System

* pt uses own muscle strength and joint movement, as well as an external supply for power

Functional Prosthesis

* Body-powered prostheses
* externally-powered prostheses
* myo-electric
* switch-controlled

Body-powered prosthesis

* by body mvmts
* moderate cost and weight
* most durable prostheses and have higher sensory feedback
* more often less cosmetically pleasing than myoelectrically controlled type d/t cables
* has more gross limb mvmt

exaggerated movements

* bi scapular abd/add
* gh flexion to operate terminal device and elbow
* gh depression to lock and unlock elbow

requirements for bps

* significant strength and control over various body parts (sh, chest, residual limb)
* sufficient limb length,
* musculature,
* rom

bpd advantages

* lower initial cost
* lighter
* easier to repair
* offer better tension feedback to the body

bpd disadvantages

* mechanical appearance
* some people have difficulty using them (coordination probs)
* dependent on motor strength

externally-powered prostheses

powered by electric motors

* from select residual muscles, detected by surface electrodes used to control electric motors
* uses muscle contractions or manual switches to activate the prosthesis
* provide more proximal function and greater grip strength compared to body-powered, improved cosmesis; heavy and expensive

available designs require more maintenances, has less sensory feedback

needs a control system

myoelectrically controlled

* uses muscle contractions as a signal to activate the prosthesis
* uses surface electrodes to detect electrical activity from select residual limb muscles to control electric motors

two-site/two function (dual site)

* separate electrode for prosthetic activity
* more physiologic and easier to control
* can mimic normal movements

one-site/two function (single site)

* limited control site in a residual limb
* for small active muscles
* uses a single electrode to control both functions of productivity
* when pt uses mm contractions of diff. strengths to differentiate b/w flexn/extn

strong contraction: open terminal device

weak contraction: close terminal device

switch controlled

* small switches to operate electric motors

Switches

* enclosed inside the socket or incorporated into the suspension harness of the prosthesis
* activated by the movement of a remnant digit or part of a bony prominence against the switch or by a pull on a suspension harness

nudge

* operate bt chin depressing the switch on the ant. chest strap

myoelectric devices advantages

* do not require a harness or cable
* looks like a natural appearing arm
* battery-powered
* motor strength and coordination not as important
* newer batteries have reduced weight
* provides strong grip force

myoelectric devices disadvantages

* higher initial cost
* heavier
* dependence on battery capacity and voltage
* higher repair cost
* dependence on battery life

socket for ue prosthe

* have a snug and intimate fit around residual limb
* has a dual wall design fabricated from lightweight plastic or graphite composite materials

rigid inner socket

* fabricated to fit the pt’s residual limb
* snug fit
* provides appropriate contact and fit
* from flexible plastic materials

outer

* designed to be same length and contour as the opposite sound lumb
* cosmesis

windows

* openings
* in the outer socket allow movement
* permit relief over bony prominences, and enhance comfort

suspension

* must hold prosthesis securely to the residual limb
* accomodate and distribute the forces associated with the weight of the prosthesis and any superimposed lifting loads

harnessed-based system

* most commonly used system

figure-8 strap

* harness loops around axilla on the sound side
* anchors the harness and provides the counterforce for suspension and control-cable forces

components hbs (figure 8 strap)

1. axilla loop
2. anterior support strap
3. control attachment strap (inverted y suspension)
4. cross point (o-ring)

figure 9 harness

* alternative for a pt with a long transradial amputation or a wrist disarticulation
* in order to provide the control harness provides minimal suspension and requires a self-suspending socket
* more comfortable than a figure 8 harness

self-suspending sockets

* largely limited to wrist or elbow disarticulations and to transradial amputations
* most commonly utilized with an externally powered, myoelectrically controlled transradial prosthesis

muenster socket

* proper fit of this socket precludes full elbow extension
* relies on pressure above the elbow to hold the prosthesis in place
* can lead to discomfort and reduced rom

suction sockets

* uses external elastic suspension sleeve; a one-way air valve; or roll-on gel suspension liner with a pin-locking mechanism
* require a total contact socket design and ideally a residual limb with no skin invagination, scarring, stable volume to avoid skin problems (choke syndrome)
* most common in transhumeral amputation

control cable mechanism

* bp prosthe limbs uses cables to link movements of 1 part of body to the prosthesis in order to control a prosthetic function
* usually a movement of the humerus, shoulder, or chest which is transferred via a cable

single-control cable

* bowden cable system
* control cable used to activate a single prosthetic component

dual controle cable system

* uses same cable to control 2 prosthetic functions
* such as flexion of elbow is locked, activation of the terminal device

wrist unit

* provides orientation of the terminal device in space
* positioned manually, by cable operation or with external power
* once positioned, wrist unit is held in place by a friction lock or mechanical lock

quick disconnect wrist unit

* configured to allow easy swapping of terminal devices that have specialized functions

locking wrist unit

* wrist unites with a locking capacity prevent rotation during grasping and lifting

wrist flexion unit

* can provide an amputee (bi lat upper limb amputee) with improved function for midline activities such as shaving, manipulating buttons, or performing perineal care
* used on only one side, most often the longer of the two residual limbs but ultimately it should be placed on the side that the amputee prefers
* multifunction wrist units are now available

Passive Terminal Device

* more on prosthesis
* passive terminal devices fall into two classes:
* for function (not moving)
* provide cosmesis
* cosmetic passive terminal devices usually are less functional and more expensive than active terminal devices

active terminal devices

* more on motion
* active terminal devices usually are more functional

2 main categories active terminal devices

* hook, prosthetic hands

hook

* lat. pinch grip
* simpler design, light weight, low maintenance, and repair cuase, permits visual feedback
* durable efficient

prosthetic hands

* three jaw chuck
* natural but less functional, and bulkier and heavier

classification of hook and prosthetic hands

voluntarily opening vs voluntarily closing

voluntarily opening

* most common type, functional, practical type
* resting position: closed hands or hook. upon elbow motion, it opens voluntarily

voluntarily closign

* most physiologic
* resting position: open hand. upon elbow motion, voluntarily closes

terminal devices: 5 types of grip

1. precision grip
2. tripod grip
3. lateral grip
4. hook-power grip
5. spherical grip

precision grip

* pincer grip
* pad of the thumb and index finger are in opposition to pick up or pinch a small object

tripod grip

* pad of the thumb is against the pads of the index and middle finger

lateral grip

* tips of the fingers and thumb are flexed

hook power grip

* dip joint and pip joint are flexed with the thumb extended

spherical grip

* tips of the fingers and thumb are flexed

Below Knee Prosthesis

* non-articulated
* components:
* foot ankle assembly
* shank
* socket
* suspension element

foot ankle assembly

* substitute for anatomic foot and ankle
* requirements:
* should provide base for weight bearing
* should absorb shock at heel contact
* rapidly reach foot flat position or plantarflexion
* should provide mtp hyperextension (metatarsal break) during push off or late stance phase
* should resemble the general contour of the missing foot for cosmesis

categories of foot ankle assembly

* non-articulated components
* articulated components

non articulated components

* no joint & joint motion can be seen
* foot is attached directly to shank c no joint and movement
* durable quieter lighter

keel

* weight supporting structure inside foot

articulated components

* plantarflexion are more readily during early stance
* heavier, more like to develop looseness, and unwanted noise
* single axis assembly
* multiple axis foot ankle assembly

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non-articulated components

* sach foot
* safe foot
* sten foot
* seattle foot
* carbon copy ii
* quantum flex-walk
* flex-foot

sach foot

* most commonly prescribed foot ankle assembly
* has a wooden rigid keel and covered by incompressible foam
* heel wedge: synthetic rubber for cushion

cushion heel

* shock absorption and plantarflexion in foot flat

belting

tough fabric under the keel to prevent puncturing of sole

bolt

* attaches foot to the shank
* allows small amount of mediolateral and transverse motion

modified sach

* nasa labas yung keel
* provides greater mediolateral stability and improve cosmesis

jaipur foot

* improved version of solid ankle cushion heel
* allows all natural movements of the foot that provides enough dorsiflexion to permit an amputee to squat
* pt can do crossed leg
* also looks like a real foot compared to sach foot
* does not need shoes

safe foot

* stationary attachment flexible endoskeleton
* heavier and more expensive than sach

rigid blot block

* stationary attachment na component/sa component

flexible keel

* fe component
* permits mediolateral and transverse motion d/t foam
* (+) plantar fascia band and long plantar ligament band

(+) plantar fascia band and long plantar ligament band

* tighten to increase structural stability
* TMT hyperextends and nababanat ito
* tarsal bones compresses

sten foot

* stored energy foot
* has 3 wooden keel and connected by two rubber plugs
* transfer of wt bearing, compresses rubber plugs then it recoils there. this is where energy are got. when compressed, it gives force outward
* duplicates sach foot, but heavier and more expensive

seattle foot

* stored energy foot
* earliest energy storing design
* known as delrin keel

delrin keel

* c-shaped with lower arm elongated as cantilever
* if delrin keel bends during wt bearing, stored energy is recoiling or returning during late stance that helps in propulsion

seattle lite foot

\-reduces wt and springiness

flex-foot

* keel extends from below knee socket to mtp joint line
* stores and returns most energy among the foot-ankle assembly
* lightest
* more expensive and requires sufficient space between the floor and residual end
* higher than flex walk

Knee Unit: above knee

Knee Socket: Below Knee

articulated components

* has joint and joint motion
* more adjustable and better in pf
* heavier
* more likely to develop closeness and unwanted noise

single axis

* has a transverse ankle axis for meeting pf and df
* pf and df only
* has a pf bumper or posterior bumper to resist pf
* compressed during pf to resist pf
* permits 15 deg pf
* dorsiflexion stop permits

multiple axis

* permits pf, df, inversion, eversion and slight amount of rotation
* tri-planar multiple axis
* has an an ankle block
* has a curved surface that rest on a rubber rock block that allow pf and df
* has a flexible joint holder that permits mediolateral motion and rotation
* multiple axis foot ankle assembly accomodates uneven walking wurfaces and absorbs torsional forces created in walking
* bulky, heavy, expensive, requires maintenance
* create instability in pt c coordination problem
* foot ankle assembly

shank

* maintains spatial relationship b/w socket and foot
* transmits load from socket above to foot below
* connects socket and foot assembly
* exoskeletal/endoskeletal

Exoskeletal

* crustacean
* made from light but strong and rigid plastic foam (sometimes wood) in which case the space b/w the bottom of the socket and ankle block should hallowed to reduce weight
* light strong waterproof finish is provided by an external lamination around the shank

endoskeletal

* central pylon
* metal of plastic tube connects socket and foot ankle assembly soft cosmetic covers around skeleton to provide life-like appearance
* proos: modest deduction of weight, incorporation of means of adjusting the alignment of prosthesis
* cons: cover is much less durable

socket

* applies weight support in amputated limb and transmit forces to move and control the prosthesis

patellar tendon bearing (ptb) socket

* most frequently used
* provides intimate fit over the entire area of the stump
* prevents edema, provides additional support area, better sensory feedback’
* incorporates compressible liners or inserts/soft inserts for pts c continuing vascular problems, sensitive tissue or fluctuating stump sites
* wb: patellar tendon, tibial flares, anterior side of tibial crest

hard socket

* only variant of ptb socket
* has no inserts
* for pts c mature residual limb c good tissue covering and for those c severe perspiration problems to provide cooling
* used for elderl c poor tissue covering

icelandic swedish new york university (isny) ptb socket

* thin, flexible, vacuum-formed thermoplastic PTB socket for tissue containment
* Main Parts:
* PTB socket
* tissue containment
* Frame
* rigid carbon fiber reinforced laminated frame for weight transmission

3 sturts of isny

* 1 posterior and 2 anterior
* connects distal end cup to the proximal segments covering the patellar tendon, medial flare, and popliteal area

pros/cons isny

pros:

* enhance comfort d/t flexibility, improve heat dissipation d/t thinnes
* ease and speed of socket modification and replacement are increased

cons:

* not as durable as laminated version, not cosmetically pleasing to other