week 11 learning objectives

Question 1

prosthetic

Answer 1

artificial body part

Question 2

residuum/residual limb

Answer 2

remains after amputation

Question 3

sound side

Answer 3

opposite limb

Question 4

don/doff

Answer 4

on/off prosthetic

Question 5

socket

Answer 5

interface between residual limb and prosthesis

Question 6

terminal device

Answer 6

hand functioning device in upper extremity

Question 7

suspension

Answer 7

how device attaches to body

Question 8

force

Answer 8

through body or device, motors

Question 9

excursion

Answer 9

ROM needed to operate upper extremity prostheses

Question 10

UE amputation statistics

Answer 10

9% of all patients with amputation
70-80% traumatic
56% of amputees use prostheses

Question 11

concepts behind UE amputation

Answer 11

cosmesis is more important than function
proficiency with UE prosthesis takes longer
most successful when viewed as tool/AD
functional difficulty proportional to amputation level

Question 12

UE amputation level

Answer 12

shoulder disarticulation, trans-humeral/elbow disarticulation, trans-radial/wrist disarticulation, trans-metacarpal/partial hand
longer is more pronation/supination

Question 13

suspension

Answer 13

how prosthesis is attached

Question 14

power strategies

Answer 14

how you move limb (generate force)

Question 15

control strategies

Answer 15

how you manipulate devices linked to limb

Question 16

UE types of suspensions

Answer 16

harness
pin-lock liner
suction
anatomical/self-suspending

Question 17

harness suspension UE

Answer 17

• the classic
• (+): simple (cables), easy to maintain (few parts), durable, accomodate heavy applications (carry heavy loads), easy donning and doffing
• (-) can be uncomfortable (into axilla, impingement), poor cosmesis
• system of straps/buckles around shoulders, back, chest
• used at all amputation levels - but is only option with should disarticulation or very short TH amputation
• many variations

Question 18

UE pin-lock liner suspension

Answer 18

• (+): comfortable, cushion bony prominences, reduce shear forces
• (-): somewhat difficult to don, harnessing usually still needed
• silicone or gel garment worn on surface of limb with distal attachment point which engages a mechanical lock
• ideal for passive prostheses
• mid-short length TH and TR

Question 19

UE suction suspension

Answer 19

• (+): interface with myoelectric control, reduce or eliminate harnessing
• (-): difficult to don - pull sock, donning sleeve, distal end discoloration, very sensitive to volume fluctuations
• skin-tight fit, seal to walls of socket, one-way expulsion valve
• most often used at TH level, some TR

Question 20

anatomical suspension/self-suspending UE

Answer 20

• (+): integrates with myoelectric control, reduce or eliminate harnessing
• (-): difficult to don, push in or pull sock, reduced ROM - risk of losing contact with epicondyles if too much flexion/extension
• socket encompasses bony prominences (humeral epidcondyles)
• trans-radial and wrist disarticulation
• can hybridize with suction

Question 21

types of power strategies

Answer 21

body power
passive
externally powered

Question 22

body power

Answer 22

• most common, highly functional
• older tech, not obsolete
• individual generates force necessary to cause movement
• body power and cable control operate together - scapulothoracic
• harnessing and cable system capture Force and Excursion produced by other body movements and use it to operate the prosthesis

Question 23

force and excursion

Answer 23

• force: strength or energy causing motion
• excursion: movement from axis, distance traveled, translates to cable travel
• each amputation level requires different movements to capture force and excursion

Question 24

force and excursion examples

Answer 24

• shoulder disarticulation: biscapular abduction, scapular elevation, chest expansion
• TH/elbow disarticulation: GH flexion, biscapular abduction, scapular depression/extension/abduction
• TR/wrist disarticulation: GH flexion, biscpaular abduction

Question 25

passive power

Answer 25

* primarily prosthetic/aesthetic * passive does not mean non-functional: can be function * functions: swivel shoulder, locking elbow, rotating wrist (can also lock), passive spring-loaded terminal device * prepositioned with sound side

Question 26

UE externally powered

Answer 26

* controlled by body, powered by motor * on-board motor provides force for motion * terminal device, wrist unit, and elbow each motorized and user-selected to function independently as determined by the control strategy

Question 27

types of control strategies

Answer 27

cable control myo-electric hybrid

Question 28

cable control

Answer 28

integrated with body power * harnessing to capture force and excursion * proper harnessing is essential (fit) * analogous to bike brake lever/shifter integrated with external power * harness connects to a linear transducer or switch

Question 29

myo-electric control

Answer 29

* most common externally powered prosthesis * electrodes embedded in (usually suction) scoket wall for contact with skin * electrodes capture electrical activity of a muscle for contact with skin * electrodes capture electrical activity of a muscle contraction and convert it into a signal * electrode placement: 2 electrodes on antagonistic muscle groups, 1 electrode on any viable site * many control strategies are possible based on number of electrodes and programming

Question 30

UE myo-electric control example

Answer 30

TH 2 electrodes * flexor: elbow flexion, pronation, TD close * extensor: elbow extension, supination, TD close * co-contract: component selection 1 electrode * contraction: one selected movement, TD close * program opens TD when relaxed

Question 31

UE hybrid control

Answer 31

* combo of cable control and myo-electric control examples: * body power cable control elbow, external power 1 channel myo control TD * OR * external power 2 channel elbow, body power cable control TD

Question 32

terminal devices replicate

Answer 32

some/all hand function

Question 33

grasp patterns

Answer 33

* cylindrical grasp * tip * hook or snap * palmar * spherical grasp * lateral

Question 34

voluntary open terminal devices

Answer 34

* most common - default is closed * use force/power to open * force and excursion open, spring or rubber bands close * pinch force is preset * max pinch force when fully relaxed

Question 35

voluntary close terminal devices

Answer 35

* open by default * force and excursion close, spring or rubber bands open * pinch force is determined by force exerted by user * TD is fully open when relax

Question 36

facts about terminal devices

Answer 36

* can be activity specific * harness good for increased load * body power for more gross motor control