Ch 6 - Prosthetics and Orthotics: Amputation and Upper Limb Prosthetics Flashcards

1
Q

What are the main causes of amputation?

A

Dysvascular disease (DM and PAD)
Trauma
Cancer
Congenital

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2
Q

What is age is the greatest risk for limb loss?

A

> 65 yo

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3
Q

What is the mortality rate of individuals with amputation due to vascular disease?

A

1/2 die w/in 5 years of amputation

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4
Q

Describe the relationship of Diabetes and amputation.

A

Contributes to 2/3 of amputations

55% of Diabetic patients with LE amputation will have amputation of 2nd leg in 2-3 yrs

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5
Q

What is the leading cause of upper extremity amputations?

A

80% trauma
Majority digital amp
UE amp account for 2/3 of trauma related amp

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6
Q

What are the standard levels of upper-limb amputation?

A
  1. Transphalangeal (DIP, PIP, MCP)
  2. Transmetacarpal
  3. Transcarpal
  4. Wrist-disarticulation
  5. Transradial (below elbow)
  6. Elbow disarticulation
  7. Transhumeral (above-elbow) >6.5 cm proximal to the elbow joint
  8. Shoulder disarticulation
  9. Forequarter amputation
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7
Q

What is a Mangled hand?

A

Irreparable damage occurs to 4 of 6 basic parts

skin, vessels, skeleton, nerves, extensor, and flexor tendons

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8
Q

Describe a wrist disarticulation.

A

Spares the distal radial ulnar articulation and thus preserves full forearm supination and pronation

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9
Q

What is the most common upper-limb amputation level?

A

Transradial amputation

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10
Q

Describe the residual limb lengths in transradial amputation.

A
  1. Very short: Residual limb length <35%
  2. Short: Residual limb length of 35% to 55%
  3. Long: Residual limb length of 55% to 90%
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11
Q

Describe the preserved supination/pronation in transradial amputation.

A

Short: 60°
Long: 60° to 120°

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12
Q

What is the ideal transradial amputation level for body-powered prosthesis.

A

Long forearm residual limb of 60-70%

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13
Q

What are the pros of elbow disarticulation?

A
  • Red surgery time and blood loss
  • Improved prosthetic self-suspension
  • Red rotation of the socket on the residual limb
  • Greater lifting, pulling, and pushing power compared to above-elbow amputation
  • No risk of HO formation
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14
Q

What are the cons of elbow disarticulation?

A
  • Cosmetic d/t external elbow mech

* Limits use of externally powered mechanisms

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15
Q

Describe the residual limb lengths of transhumeral amputation.

A
  1. Humeral neck: <30%.
  2. Short transhumeral: 30%-50%.
  3. Standard transhumeral: 50%-90%.
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16
Q

What transhumeral ampuation length will give best control and function of prosthesis?

A

90% of humeral length

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17
Q

When are shoulder disarticulations or forequarter amputations typically seen?

A

Surgical removal of malignant lesion

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18
Q

What are characteristics of passive terminal devices?

A

– Lighter

– Have no functional mechanisms and provide no grasp

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19
Q

What are types of passive terminal devices (upper extremity)?

A

a. Passive hand: cosmetic use
b. Flexible passive terminal devices: can fit into a glove or mitt for sports and other activities
c. Specialty terminal devices with adapters for sports equipment, hand tools, or kitchen utensils

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20
Q

Describe the grip of a prosthetic hand.

A

3-jaw chuck pinch (grip w/ thumb, index, and middle fingers)

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21
Q

Describe the grip of a hook.

A

Lateral or tip pinch (lateral or key grip w/ pulp of the thumb w/ lateral aspect of finger)

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22
Q

What amount of force is added with each rubber band or spring on terminal devices?

A

Each rubber band provides about 1 pound of pinch force

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23
Q

What is the most common and practical body-powered terminal device?

A

Voluntary-opening

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24
Q

How are Externally powered terminal devices controlled?

A

Switches or myoelectric signals

25
What are prosthetic wrist units used for?
Attaching terminal devices to prostheses | Provide Pronation and supination
26
What does a wrist flexion unit allow terminal devices to do?
Be in flexed position, facilitating ability to perform activities close to the body
27
When are electric wrist rotators considered?
Bilateral UE amputee
28
Describe a friction wrist.
Permit pronation and supination of the terminal device and hold it in a selected position by means of friction
29
Describe a locking wrist.
Permit manual rotation | Lock terminal device in fixed position
30
Describe a split socket for transhumeral amputation.
Total-contact segment encasing the residual limb and connected by hinges to a separate forearm shell which wrist unit and the terminal device are attached
31
When would a split socket for transhumeral amputation be used?
Patients who have very short residual limbs
32
Describe a Meunster socket.
Socket and forearm are set in flexion and the socket encloses the olecranon and epicondyle of the humerus
33
What is the most commonly used harness?
Figure-8 (O-ring) harness
34
Describe a Figure-8 (O-ring) harness.
–Axilla loop, on sound side, acts as a reaction point for the transmission of body force to the terminal device –Anterior suspension strap on involved side gives support for pulling or lifting, and attachment for the elbow loading strap
35
Describe a Figure-9 harness.
Used with self-suspended transradial socket that requires a harness only for controlling the terminal device or for long residual limbs with suction sockets
36
Describe a Chest-strap with shoulder saddle.
Used if the patient cannot tolerate the axilla loop or doing heavy lifting
37
What is a single-control cable system (Bowden cable system) used in?
Transradial single-control cable system
38
What is a single-control cable system (Bowden cable system) consist of?
One cable to transmit body power for a single purpose—to operate the terminal device
39
What are the muscle movements to operate the terminal device of a single-control cable system (Bowden cable system)?
Forward humeral flexion and biscapular abduction.
40
What is a dual-control cable system (split cable or fair lead cable system) used in?
Transhumeral control-cable system | Very short transradial split-socket prosthesis with locking hinge
41
What are the functions of a dual-control cable system (split cable or fair lead cable system)?
Flex the elbow unit when the elbow is unlocked | Operate the terminal device when the elbow is locked
42
What does an elbow disarticulation prosthesis provide?
Self-suspension | Allows for IR and ER of the humerus
43
When are External (outside) locking elbows used?
Elbow-disarticulations when residual limb extends more distally than 4 cm to the level of the epicondyles to maintain the elbow joint center equal to that in the nonamputated side
44
When are internal locking elbows used?
Transhumeral and shoulder prostheses | Amputation 4 cm or more proximal to the level of the epicondyles
45
Why are internal locking elbows preferred?
Greater mechanical durability | Cosmetically more appealing
46
Which harness design is most frequently used for transhumeral prostheses?
Modifications of the basic figure-8 and chest-strap patterns used with transradial prostheses
47
How is an elbow flexed from an unlocked and extended position in transhumeral prosthesis?
Flexing the shoulder (humeral flexion; assisted by biscapular abduction) transmits force to the forearm lever loop flexing the elbow to the desired level
48
How is an elbow locked/unlocked in transhumeral prosthesis?
Shoulder depression, extension, and abduction—“down, back, out”
49
How is the terminal device operated in transhumeral prosthesis?
Shoulder flexion and biscapular abduction
50
How is an elbow extended in transhumeral prosthesis?
Elbow is unlocked and the elbow extends by gravity
51
How are myoelectric terminal devices opened in below-elbow amputees?
Wrist extensors (extensor carpi radialis longus/brevis and extensor carpi ulnaris)
52
How are myoelectric terminal devices closed in below-elbow amputees?
Wrist flexors (flexor carpi radialis and flexor carpi ulnaris)
53
How are myoelectric terminal devices opened and elbows flexed in above-elbow amputees?
Biceps muscle
54
How are myoelectric terminal devices closed and elbows extended in above-elbow amputees?
Triceps muscle
55
How are myoelectric terminal devices and elbows controlled in transhumeral or shoulder amputees?
Shoulder girdle muscles
56
What are advantages of Body-powered devices?
``` Less expensive Lighter More durable Easier to repair Higher sensory feedback ```
57
What are disadvantages of Body-powered devices?
Mechanical appearance Difficult to use for some people Dependent on motor strength
58
What are advantages of Myoelectric devices?
Better cosmesis Less harnessing Stronger grasp force
59
What are disadvantages of Myoelectric devices?
More expensive Heavier Decreased durability due to electronic components and the need for daily recharging of batteries.