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
Q

What are prosthetic wrist units used for?

A

Attaching terminal devices to prostheses

Provide Pronation and supination

26
Q

What does a wrist flexion unit allow terminal devices to do?

A

Be in flexed position, facilitating ability to perform activities close to the body

27
Q

When are electric wrist rotators considered?

A

Bilateral UE amputee

28
Q

Describe a friction wrist.

A

Permit pronation and supination of the terminal device and hold it in a selected position by means of friction

29
Q

Describe a locking wrist.

A

Permit manual rotation

Lock terminal device in fixed position

30
Q

Describe a split socket for transhumeral amputation.

A

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
Q

When would a split socket for transhumeral amputation be used?

A

Patients who have very short residual limbs

32
Q

Describe a Meunster socket.

A

Socket and forearm are set in flexion and the socket encloses the olecranon and epicondyle of the humerus

33
Q

What is the most commonly used harness?

A

Figure-8 (O-ring) harness

34
Q

Describe a Figure-8 (O-ring) harness.

A

–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
Q

Describe a Figure-9 harness.

A

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
Q

Describe a Chest-strap with shoulder saddle.

A

Used if the patient cannot tolerate the axilla loop or doing heavy lifting

37
Q

What is a single-control cable system (Bowden cable system) used in?

A

Transradial single-control cable system

38
Q

What is a single-control cable system (Bowden cable system) consist of?

A

One cable to transmit body power for a single purpose—to operate the terminal device

39
Q

What are the muscle movements to operate the terminal device of a single-control cable system (Bowden cable system)?

A

Forward humeral flexion and biscapular abduction.

40
Q

What is a dual-control cable system (split cable or fair lead cable system) used in?

A

Transhumeral control-cable system

Very short transradial split-socket prosthesis with locking hinge

41
Q

What are the functions of a dual-control cable system (split cable or fair lead cable system)?

A

Flex the elbow unit when the elbow is unlocked

Operate the terminal device when the elbow is locked

42
Q

What does an elbow disarticulation prosthesis provide?

A

Self-suspension

Allows for IR and ER of the humerus

43
Q

When are External (outside) locking elbows used?

A

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
Q

When are internal locking elbows used?

A

Transhumeral and shoulder prostheses

Amputation 4 cm or more proximal to the level of the epicondyles

45
Q

Why are internal locking elbows preferred?

A

Greater mechanical durability

Cosmetically more appealing

46
Q

Which harness design is most frequently used for transhumeral prostheses?

A

Modifications of the basic figure-8 and chest-strap patterns used with transradial prostheses

47
Q

How is an elbow flexed from an unlocked and extended position in transhumeral prosthesis?

A

Flexing the shoulder (humeral flexion; assisted by biscapular abduction) transmits force to the forearm lever loop flexing the elbow to the desired level

48
Q

How is an elbow locked/unlocked in transhumeral prosthesis?

A

Shoulder depression, extension, and abduction—“down, back, out”

49
Q

How is the terminal device operated in transhumeral prosthesis?

A

Shoulder flexion and biscapular abduction

50
Q

How is an elbow extended in transhumeral prosthesis?

A

Elbow is unlocked and the elbow extends by gravity

51
Q

How are myoelectric terminal devices opened in below-elbow amputees?

A

Wrist extensors (extensor carpi radialis longus/brevis and extensor carpi ulnaris)

52
Q

How are myoelectric terminal devices closed in below-elbow amputees?

A

Wrist flexors (flexor carpi radialis and flexor carpi ulnaris)

53
Q

How are myoelectric terminal devices opened and elbows flexed in above-elbow amputees?

A

Biceps muscle

54
Q

How are myoelectric terminal devices closed and elbows extended in above-elbow amputees?

A

Triceps muscle

55
Q

How are myoelectric terminal devices and elbows controlled in transhumeral or shoulder amputees?

A

Shoulder girdle muscles

56
Q

What are advantages of Body-powered devices?

A
Less expensive
Lighter
More durable
Easier to repair
Higher sensory feedback
57
Q

What are disadvantages of Body-powered devices?

A

Mechanical appearance
Difficult to use for some people
Dependent on motor strength

58
Q

What are advantages of Myoelectric devices?

A

Better cosmesis
Less harnessing
Stronger grasp force

59
Q

What are disadvantages of Myoelectric devices?

A

More expensive
Heavier
Decreased durability due to electronic components and the need for daily recharging of batteries.