Transtibial Prosthetics Flashcards Preview

735: Orthotics and Prosthetics > Transtibial Prosthetics > Flashcards

Flashcards in Transtibial Prosthetics Deck (78)
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1
Q

What is the preferred length of the residual limb? Explain why…

A

6-7 inches

There is sufficient calf musculature but it is not too long as in to limit the use of good prosthetic feet

2
Q

What are the 3 goals post-op transtibial amputation?

A
  • facilitate healing
  • reduce edema
  • prevent contractures
3
Q

What are the 2 most common contractures in transtibial amputees?

A

hip and knee

4
Q

What are the 4 types of “dressings” that can be used to reduce edema?

A
  • immediate post-op prosthesis
  • removable rigid dressing
  • ACE wrap
  • BK shrinker
5
Q

What is a disadvantage to using a IPOP?

A

They are typically not user friendly

6
Q

What are 3 common mistakes when using an ACE wrap?

A
  • just wrapping the distal end
  • not wrapping at an angle
  • do not cover everything that is within the prosthesis
7
Q

What is 1 advantage and 1 disadvantage to using a shrinker sock?

A

Patients can usually don/doff this independently

It may be tender to the patient

8
Q

When should the patient be fitted for their preparatory prosthesis?

A

Around the 6-8 week mark to allow for wound healing

9
Q

What are the 3 purposes of the preparatory prosthesis?

A
  • early ambulation
  • shape of the residual limb
  • cost effective
10
Q

How long is the preparatory prosthesis typically worn for?

A

6-8 months

11
Q

What are the 6 components of the preparatory prosthesis?

A
  • prosthetic socks
  • socket suspension
  • socket insert/end pad
  • socket
  • pylon
  • foot
12
Q

What are 2 of the materials a socket can be made out of?

A
  • laminated

- polypropylene

13
Q

Why is the socket insert/end pad essential in transtibial amputations?

A

Cushions the numerous bony prominences

14
Q

What type of prosthetic foot is typically used on the preparatory prosthesis?

A

SACH foot

15
Q

What is the advantage on the SACH foot having a cushion heel?

A

It allows for foot flat without the ankle moving

16
Q

What indicates the thickness of the prosthetic socks?

A

1, 2, 3, 4, ply

17
Q

When donning the prosthetic sock it is essential to avoid what?

A

wrinkles

18
Q

What is the main purpose of the prosthetic sock?

A

It positions the residual limb in the socket

*not used for suspension, comfort, etc.

19
Q

When is a patient considered “ready” to be fitted for their definitive prosthetic?

A

When the residual limb has a constant volume

20
Q

What are the 2 construction design of the definitive prosthetic?

A
  • exoskeletal (not common)

- endoskeletal

21
Q

What are the 3 advantages to using an exoskeletal prosthetic?

A
  • durable
  • lightweight
  • cost effective
22
Q

What are the 3 disadvantages to using an exoskeletal prosthetic?

A
  • cosmesis
  • alignment cannot be adjusted
  • there is a limited component selection
23
Q

What are the 3 advantages to using an endoskeletal prosthetic?

A
  • cosmesis
  • alignment can be adjusted
  • wide variety of component selection
24
Q

What are the 3 disadvantages to using an endoskeletal prosthetic?

A
  • expensive
  • durability
  • weight
25
Q

Although endoskeletal prosthetics are becoming lighter in weight, what is one way in which they are perceived as lighter?

A

When the weight is placed proximally rather than distally

26
Q

What are the 4 types of socket designs? What 2 are used the most?

A
  • patella tendon bearing*
  • total surface bearing*
  • open end
  • knee joints and thigh lacers
27
Q

True or False

Socket length is identical to the residual limb length

A

True

28
Q

What is the idea behind the total surface bearing socket?

A

the more area that is loaded, the less pressure that is felt on any one area/prominence

29
Q

In what type of patient are knee joints and thigh lacers used in?

A

Those with poor knee stability and short residual limbs

30
Q

How do thigh lacers enhance knee stability?

A

They lengthen the lever arm

31
Q

What are the 7 types of suspension techniques?

A
  • waist belt
  • supracondylar cuff
  • supracondylar sleeve
  • supracondylar wedge
  • suction suspension
  • pin suspension
  • sub-atmospheric suspension (vacuum)
32
Q

How does the supracondylar wedge create suspension?

A

The medial femoral condyle produces a “shelf” for the wedge to sit on

33
Q

What does the supracondylar wedge suspension system result in?

A

Atrophy proximal to the knee

34
Q

What are 2 ways in which the prosthetic socket achieves suction via suction suspension?

A
  • expulsion valve

- suspension sleeve

35
Q

What is the #1 method of socket suspension?

A

sleeve suspension with an expulsion valve

36
Q

When donning a suspension sleeve what is one thing to ensure the patient does?

A

Ensure the sleeve is pulled up over the socks and is in contact with the skin

37
Q

What is an advantage to the pin suspension method?

A

It is quick and easy (say they have to get in and out of bed frequently throughout the night)

38
Q

What is a disdvantage to the pin suspension method?

A

The suspension is not very good which creates pistoning and rotation of the residual limb

39
Q

What type of patients cannot use vacuum suspension methods?

A

Those who’s body volume changes often (new amputees, diabetics, etc.)

40
Q

What are the 2 advantages to using vacuum suspension?

A
  • creates a large constant suspension

- eliminates pistoning

41
Q

What are the 4 types of socket liners and which are the most common?

A
  • gel*
  • pelite*
  • multidurometer
  • hard socket
42
Q

What are the 5 basic categories of prosthetic feet?

A
  • SACH
  • single axis
  • multiaxis
  • flexible keel
  • energy storing
43
Q

What does SACH stand for?

A

Solid Ankle Cushion Ankle

44
Q

Are single axis feet endo- or exoskeletal?

A

They can be either

45
Q

A SAFE foot is a commonly used flexible keel foot, what does it stand for?

A

Stationary Attachment Flexible Keel

46
Q

What is the brand name of an energy storing foot that looks real in appearance?

A

Seattle foot

47
Q

What material are energy storing feet typically made of?

A

carbon

48
Q

What are 4 brand names of energy storing feet?

A
  • Flex Walk Foot
  • VSP
  • Reflex Rotate
  • Flex
49
Q

What is the significance of the split toe on energy storing feet?

A

It allows for ground manipulation such as rocks

50
Q

What are 3 disadvantages to the Symes amputation?

A
  • very limited on foot selection
  • typically too tender for weightbearing
  • cosmetically unppealing
51
Q

What type of prosthetic is required in a Symes amputee?

A

One with a posterior opening (window) that allows the bulbous end to fit down into the prosthetic

52
Q

What is the most common place for a sore to develop on the transtibial amputee?

A

anterior-distal tibia

53
Q

What are 7 possible causes of anterior-distal tibia soreness?

A
  • not enough socks
  • patient wearing shoes with too high of a heel
  • foot placed too posterior
  • too much flexion in the socket
  • heel is too stiff
  • posterior shelf too low
  • not enough relief in the socket
54
Q

What are the 5 stages of prosthesis design?

A

1) patient evaluation
2) impression technique
3) positive model modification
4) socket fabrication
5) alignment process

55
Q

What are the 3 purposes of the preparatory prosthesis?

A
  • early ambulation
  • shaping of the residual limb
  • cost effective
56
Q

What are the weightbearing surfaces of the PTB socket?

A
  • patellar bar

- medial flare of the tibia

57
Q

What is the purpose of the posterior shelf in the PTB socket?

A

Gives room to the hamstrings

58
Q

Where must the posterior shelf be aligned with and why?

A

The patella tnedon in order to provide counterforce

59
Q

What are the 3 biomechanical objectives of the PTB socket?

A
  • maximize the weight bearing surface
  • maintain ML stability
  • encourage knee flexion throughout stance phase
60
Q

What are the 6 surfaces of the residual limb that are pressure tolerant?

A
  • patella tendon
  • medial tibial flare
  • medial tibia
  • pre-tibial muscles
  • shaft of the fibula
  • gastrocnemius
61
Q

What are the 7 surfaces of the residual limb that are pressure sensitive?

A
  • tibial tubercle
  • tibial crest
  • anterior-distal tibia
  • fibular head
  • peroneal nerve
  • distal fibula
  • hamstrings tendons
62
Q

What are the 3 alignment stages?

A

1) bench alignment
2) static alignment
3) dynamic alignment

63
Q

In transtibial prosthetics the goal is to maintain a _____ moment during stance phase

A

flexion

64
Q

How can the knee flexion moment be increased?

A

By flexing the socket which will cause increased foot dorsiflexion and therefore promote knee flexion

*ski boot example

65
Q

If the socket is not flexed enough what will occur?

A

the foot will plantarflex and knee hyperextension will occur

66
Q

Where is the pressure distributed if there is a flexion moment?

A

anterior distal and posterior proximal

67
Q

The more _____ the socket is the more flexion moment there is

A

posterior

68
Q

A flexed socket also _____ the surface area of the load

A

increases

69
Q

During what phase of gait is there an extension moment?

A

heel off

70
Q

Typically how big are prosthetic feet in regards to shoe size?

A

1/2 size smaller

71
Q

What things should you look for in regards to the pylon during bench alignment?

A

it should be vertical

72
Q

What landmark is used to base the prosthetic measurement?

A

patellar tendon

73
Q

In the coronal plane the socket should be vertical and aligned in - degrees of adduction

A

5-7

74
Q

Describe what will happen if the foot is inset too far

A

The socket moves laterally and produces lateral distal and medial proximal pressures

75
Q

Describe what will happen if the foot is outset too far

A

The socket moves medially and produces medial distal and lateral proximal pressures

76
Q

If the patient demonstrates genu valgum the solution is to ____ the foot.
If the patient demonstrates genu varum the solution is to ____ the foot.

A

inset

outset

77
Q

The prosthetic should be rotated so that there is how many degrees of toe-out?

A

5-7 degrees

78
Q

As toe out increases the lever arm ____.

A

decreases