Exam 5: Prosthetics TransTib ReadGuide/Lecture/Chart, Intro, Sockets Flashcards Preview

Bringman class fall 2015 > Exam 5: Prosthetics TransTib ReadGuide/Lecture/Chart, Intro, Sockets > Flashcards

Flashcards in Exam 5: Prosthetics TransTib ReadGuide/Lecture/Chart, Intro, Sockets Deck (81):
1

Why is it important to individualize prosthetic prescriptions?

One size does not fit all: the ideal prosthesis for one person may be completely useless to another.

It is only with careful consideration of the person’s complete profile that the clinical team can recommend the components and design that will lead to the most optimal prosthetic outcomes.

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2

How does an individual’s functional potential relate to prosthetic prescription?

There are K-Levels from CMS which is a hierarchical system to classify the functional potential of persons with lower limb amputations. Each functional level uses the phrase “has the ability or potential” in the description, because individuals cannot reach their full potential until their prosthesis is provided and rehabilitation has been successful

For certain benefits to be covered under Medicare, the individual must be certified by his or her prosthetist and MD with the appropriate K-level (to prevent prescription of prosthesis with costly components that person will not be able to manage or use effectively).

3

What are K-levels?

There are K-Levels from CMS which is a hierarchical system to classify the functional potential of persons with lower limb amputations. Each functional level uses the phrase “has the ability or potential” in the description, because individuals cannot reach their full potential until their prosthesis is provided and rehabilitation has been successful

For certain benefits to be covered under Medicare, the individual must be certified by his or her prosthetist and MD with the appropriate K-level (to prevent prescription of prosthesis with costly components that person will not be able to manage or use effectively).

4

How many K Levels are there and what are thier names?

5 Levels

  • K0
  • K1
  • K2
  • K3
  • K4

5

K0

The patient does not have the ability or potential to ambulate or transfer safely with or without assistance and a prosthesis does not enhance quality of life or mobility

6

K1

The patient has the ability or potential to use a prosthesis for transfers or ambulation on level surfaces at fixed cadence. Typical of the limited and unlimited household ambulator..

7

K2

The patient has the ability or potential for ambulation with the ability to traverse low-level environmental barriers such as curbs, stairs, or uneven surfaces. Typical of the limited community ambulator.

8

K3

The patient has the ability or potential for ambulation with variable cadence. Typical of the community ambulator who has the ability to transverse most environmental barriers and may have vocational, therapeutic, or exercise activity that demands prosthetic utilization beyond simple locomotion.

9

K4

The patient has the ability or potential for prosthetic ambulation that exceeds basic ambulation skills, exhibiting high impact, stress, or energy levels. Typical of the prosthetic demands of the child, active adult, or athlete.  

10

What is the relationship between prostatic weight and design, and weight and energy expenditure?

Prosthetic design is often a compromise of weight versus function.

Increased weight leads to increased energy expenditure and premature fatigue.

However, exclusion of features that the person will need on a regular basis (but may be heavy) may lead to excessive stresses on the limb, premature component wear or breakdown, and inefficient gait.

11

What does RRD stand for?

Ridgid removeable dressing

12

What does IPOP stand for?

Immediate postoperative prosthesis

 

It is an prosthesis made immediately after surgery to help with edema and contracture control as well as early ambulation.  I think the socket is usually made out of plaster and custom made.

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13

True/False: wrapping a residual limb postoperatively with an elastic bandage is superior to using a RRD (that's why we learned it last semseter with Dr. Bringman)

False:

It has ben shown that RRDs provide more favorable outcomes than elastic bandages when used to control postop edema and provide protection to the surgical site.

 

*We likely learned how to wrap a residual limb with the elastice bandage because it is cheaper (common) and requires practice to learn how to put it on?

14

What are three good  things an RRD does?

  1. keeps the knee in full extension to prevent contracture
  2. protects the limb from exterior trauma
  3. controls swelling through total contact

15

Describe at least three advantages of the IPOP over the traditional approach of waiting for healing to take place and then fit a prosthesis weeks or months later.

  1. Includes serving the same purpose as the RRD
    • Provides more favorable outcomes than elastic bandages when used to control postop edema and provide protection to the surgical site.
      • keeps the knee in full extension to prevent contracture
      • protects the limb from exterior trauma
      • controls swelling through total contact
  2. Allows supported weight bearing for early mobility

16

How much weight bearing should be allowed through an IPOP?

It is important to note that weight bearing while in an IPOP should be at the level of TTWB. FWB is discouraged as there is generally not enough area to distribute the full body weight in a manner that the skin will tolerate for extended periods of time.

An assistive device should be used

 

17

How are IPOPs able to allow weight bearing without hurting the incision?

IPOP sockets are desined to allow some weight-bearing forces direct to the medial tibial flare and patellar tendon because these structures are far from the surgical site and are not likely to be impacted by post-operative edema.

18

If they are so great, why doesn't everyone recieve an IPOP?

  • IPOP may not be used due to excessive soft tissue damage or delayed wound healing  
  • I'm thinking that they are also expensive and require specialized equipment and training to fabricate and use (basically a prosthetist has to make them?)

19

What is the next best thing to the IPOP for achieving residual limb management and how does it work?

(also, what is it made of?)

  • a RRD can be used- it can have a custom-molded plaster socket with a prefabricated plastic collar
  • RRD helps by- keeping knee in full extension to prevent contracture, protects the limb from exterior trauma, controls the swelling through total contact

20

What are the two main types of TT (transtibial) sockets?

  1. Patellar Tendon-Bearing Socket (PTB Socket)
    • older; rarely used
    • Has a very deep patellar bar
    • designed to strategically load the limb in areas that are more pressure tolerant, namely the patellar tendon and medial tibial flare, and to relieve the tissue over bony prominences like the tibial crest and head of the fibula.  In most cases, this eliminated the need for proximal WB
  2. Total Surface-Bearing Socket
    • newer; mostly replaced PTB (considered the standard now)
    • Less contouring around the patella
    • tries to distribute the WB load over the entire surface of the limb (even places that have been traditionally thought as pressure intolerant)

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21

In PTB

What are the two main weight-bearing surfaces?

patellar tendon and medial tibial flare

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22

In the PTB

What is the height of the posterior trimline? Why?

posterior wall is just proximal to the patellar bar to stabilize the limb in the anteroposterior direction and to prevent the limb from sliding too far down into the socket; should be lower on the medial side to accommodate the insertion of the medial hamstring during knee flexion

23

In the PTB

What residual limb complication results if the patient does NOT have total contact inside the socket?

Swelling of the non-contact areas

24

What was the goal of the PTB socket?

goal of PTBS- to increase surface area on residuum to eliminate the need for the knee joint and thigh corset (they socket it replaced)

25

sockets: What is "total contact"?

“total contact”- should be no void or air pockets

26

Describe the alignment of the PTB socket, what type of material is inside the socket, and any particular stability features

  • Socket is aligned in approximately 5 degrees of knee flexion, which allows the bar to act as a weight bearing surface within the socket.
    • (Gets its name from the use of a patellar "bar" that is built into the socket at the level of the center of the patellar ligament, midway between the patella dn the tibial tubercle)
  • distal end of the socket with complaint foam material for WB- necessary to control distal edema
  • medial and lateral walls extend up to level of adductor tubercle to provide level arm for ML stability

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27

What looks like an interesting place to visit in Milledgevill, Georgia?

Old Governor's Mansion

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28

What is a big difference between the TSB socket and the PTB socket?

TSB socket tries to distribute the WB load over the entire surface of the limb (even places that have been traditionally thought as pressure intolerant). The PTB socket tries to distribute weight only to the tibial plateu and patellar tendon.

29

How does the Total Surface Bearing Socket work and what needs to be taken into consideration?

 

  1. strategic compression of soft tissue and relief of bony prominences- direct more force into area of the limb that can be tolerated
  2. force changes through gait cycle- dynamic pattern must be anticipated so as to use those forces to design the relief for pressure intolerant areas; large forces= tissue compression which need more relief; need to consider density and structure of the tissue being compressed
  3. Flexible inner socket is often paired/part-of this socket? (totally confused about this - emailed Dr. Mincer to help me understand how the flexible inner socket fits in the grand scheme of sockets)

30

What is the usual skin interface material used in the TSB socket?

Gel liners are a key component of TSB sockets

  • Gel liner could be worn directly against the skin
  • “Liner liner” could be worn against the skin under the gel liner.

31

  1. True/False: gel liners can be worn against the skin
  2. True/False: gel liners are always worn one way

  1. True
    • Gel liner could be worn directly against the skin
  2. False
    • “Liner liner” could be worn against the skin under the gel liner

32

List four functions of the prosthetic sock.

  1. Help accommodate changes in volume of the residual limb (probably the most important)
    • (provides the individual with a method to control socket fit)
  2. Help cushion the forces applied to the residual limb during ambulation
    • shock absorption
    • shear forces
  3. Wick moisture that might accumulate during wear away from the skin
  4. Some have silver fibers in the sock to enhance antimicrobial properties

"provides the individual with a method to control socket fit"

“provides shock absorption, decrease the shear forces on the limb, and wick away moisture”

 

33

How is a sheath different from a sock?

Sock (thicker than sheath)

  • made from various combos of  cotton, nylon, wool , lycra, polyester. May include silver fibers.
  • Provides shock absorption, decreases shear forces, wicks away moisture, provides method to control socket fit by changing the numbers of ply.

Sheath (thin like women's panty-hose)

  • nylon
  • initial layer against skin (under sock) to further decrease friction on skin.
  • very thin stocking-like garments worn between the skin and prosthetic sock or socket liner
  • used to reduce friction, disperse moisture, and control bacterial growth

34

What main benefit does a soft insert provide?

  • Closed cell foam → does not absorb moisture
  • Increased protection- a distal end pad (an extra layer of soft material) used to cushion distal end of tibia
  • provides an extra layer of cushioning that is needed for mature limbs that lack adequate thickness
  • Soft inserts that can deform during the donning process can be used to accommodate anatomic irregularities that would not be able to slide directly into a rigid socket. You put the soft insert over the limb, then slide them both into the rigid socket. (probably main benefit)

Examples:

  • insert for a limb with a bulbous distal end can be made thicker in the narrow area above the bulge so that the diameter of the finished socket would not impede donning
  • Wedge needed for supracondylar suspension can be integrated as part of the soft insert to facilitate ease of donning.

35

How would a flexible inner socket function with a particular type of socket to provide weight distribution?

 

Additional Questions:

  • What is it?
  • Who is it useful for?
  • Who is it not good for for?

Pretty confused about this question from the reading guide. Emailed Dr. Mincer about it.

Here is what I had about it before:

  • Incarnation of PTB (patellar tendon-bearing) theory (direct weight bearing into specific areas of the limb and away from others).
  • Made with material that stretches upon application of force. A rigid frame is built around the inner socket, corresponding to areas of the residual limb where weight bearing is desirable. (I think this is the particular type of socket she is asking about?  a PTB socket?)
  • Results in socket that flexes away from forces in non-pressure tolerant areas, but remains rigid in the force-tolerant areas.
  • useful for a person with particular boney prominences and those with severe localized sensitivity
  • not for- residual limbs with adherent scarring
  • I think the picture is a type of flexible inner socket.

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36

What shape of residual limb is the expandable wall socket designed for and how does it work to facilitate socket fit and suspension?

  • Residual limb shape: distal end has greater diameter than proximal part (bulbous shape).
    • Example given was a limb amputated at or below the ankle, leaving the malleoli intact.
  • The expandable wall socket is made from an elasticized material that stretches enough for the individual to push his or her limb through in weight bearing, and tightens up over the malleoli to provide suspension.  To allow for attachment of a foot, a rigid frame is made over the flexible socket with a small space between them in which the expansion can occur.

37

Three types of gel liners

(and details of each if you like)

  1. silicone elastomers- highest compressive stiffness values, so they are best suited to support loading without deforming; benefit- limb that has a high proportion of soft tissue
  2. silicone gels-  lowest compressive and shear stiffness; useful in reducing compressive loading and eliminating shear forces on the limb; would benefit a boney limb, but might compromise the stability by creating excess motion on a limb that has more biological soft tissue
  3. urethanes- shows the highest coefficient of friction with skin (useful for preventing localized skin tension and shear)

38

What is distinctive about silicone elastomer gel liners?

  • Distinctions in friction/shear/compression?
  • useful for for?
  • benefit what type of limb?

silicone elastomers- highest compressive stiffness values, so they are best suited to support loading without deforming; benefit- limb that has a high proportion of soft tissue

 

39

What is distinctive about silicone gels gel liners?

  • Distinctions in friction/shear/compression?
  • useful for for?
  • benefit what type of limb?

silicone gels-  lowest compressive and shear stiffness; useful in reducing compressive loading and eliminating shear forces on the limb; would benefit a boney limb, but might compromise the stability by creating excess motion on a limb that has more biological soft tissue

40

What is distinctive about urethane gel liners?

  • Distinctions in friction/shear/compression?
  • useful for for?
  • benefit what type of limb?

urethanes- shows the highest coefficient of friction with skin (useful for preventing localized skin tension and shear)

 

did not say what type of limb (I have not thought it through yet, feel free to insert that here later)

41

How does a locking liner work?

There is a small locking pin in the distal end of the gel liner that locks into the socket to suspend the prosthesis.

(as opposed to a "cusion liner" that has no pin)

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42

True/False: PTs seldom work with amputees

False

PTs work a lot with amputees,

43

What 2 types of amputee do PTs most often work with?

especially pts with LE amputation

especially pts with vascular amputations

 

44

What might a PT work on with an amputee immediately after amputation?

Right after amputation

  1. Prepare for a prosthesis
    • Education: positioning, wrapping,
  2. Immediate Function
    • be able to walk with AD, transfer, etc.

45

What is a PT's goal when working with an amputee that has been fitted for  a prosthesis?

Help them learn to ambulate the best they can w/ that prosthesis

46

Who does the PT often partner with when working with an amputee that has been fitted for a prosthesis?

Prosthetist

47

When working together to help an amputee, what are the main roles of the prosthetist and the PT?

  • Prosthetist deals with the hardware
  • PT deals with the training part

**They interact on a regular basis

48

True/False: Often are the ones that recognize when the prosthesis needs to be adjusted

True

If this happens, the PT should call the prosthetist. Do not try to adjust a prosthesis ourselves.

49

What is an important question to always be asking ourselves when working with an amputee that has been fitted for a prosthesis?

Ask ourselves: is that a prosthesis problem that needs referral back to prosthetist or a PT problem that we can fix?

(is it a hardware problem or a changable problem with the amputee)

50

What is the difference between the following terms (how should each be used)?

  • Prosthesis
  • Prostheses
  • Prosthetic
  • Prosthetics

GET THESE RIGHT!

  • Prosthesis = singular noun
    • This prosthesis is fitted properly.
  • Prostheses = plural noun
    • This pt needs help with two prostheses because he underwent bilateral amputation.
  • Prosthetic = adjective, not a noun
    • This pt has a prosthetic limb.
  • Prosthetics = the study of prosthetics (the field)
    • I know someone who works in the field of prosthetics.

51

What are three types of forces often discussed in prosthtetics?

 

Forces: cannot use terms interchangeably (all types of forces)

  1. Pressure
  2. Friction
  3. Shear

52

What is the difference between shear and friction?

Friction is more on surface. Caused by two surfaces rubbing across each other. Can be seen on the skin.

Shear is deeper (will not see it on the skin. It creates a deeper injury from forces pulling in opposite directions parallel to skin but deeper than skin). 

Shear Reminds me of the very deep blisters I used to get on my toe sometimes from pointe shoes as opposed to the very shallow blisters I might get from wearing ill-fitting sandels too long (friction). But I don't think you can usually see the injury from shear unless it is really bad and causes a pressure ulcer.

 

(I didn't get this too well. Please change the card if you have a better definitinon!)

Here is a link that seemed to explain it: http://journals.lww.com/aswcjournal/fulltext/2004/06000/did_you_know__the_difference_between_friction_and.6.aspx

Shear is a “mechanical force that acts on an area of skin in a direction parallel to the body’s surface. Shear is affected by the amount of pressure exerted, the coefficient of friction between the materials contacting each other, and the extent to which the body makes contact with the support surface.”

Shear injury will not be seen at the skin level because it happens beneath the skin. Elevation of the head of the bed increases shear injury in the deep tissue, and may account for the number of sacral ulcers seen in practice.

Unlike shear injury, friction injury will be visible. Friction is the “mechanical force exerted when skin is dragged across a coarse surface such as bed linens.” 1 Simply, it is 2 surfaces moving across one another.

53

Somewhere that looks nice to visit in Guyana

Kaieteur National Park

It has Kaieteur Falls, which is the world's largest single-drop waterfall by volume (according to wikipedia)

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54

What are two effects that we went over in class related to alignment?

Heel Effect

Contracture Effect

55

What is a pylon?

In a endoskeletal prosthesis, it is the bar that connects the socket to the foot.

Like endoskeleton version of a shank

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56

TransTib Prosthetics: What is a shank?

The part of a exoskeltal prosthesis that connects the socket to the foot.

Like the exoskeleton version of a pylon

(picture is of a corbon exoskeleton)

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57

What is the Heel Effect?

If you raise the heel, the pylon or shank will follow

(because there is little to no movement at the ankle joint)

If you raise the toes, the pylon or shank will follow and rock posterior, but this is less common (but think about climbing a hill)

 

Picture is of an orthosis, but the effect is the same in this case. Pretend the orthosis has no joint (is a solid orthosis), and you get the idea.

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58

What is the assumption for the heel effect?

the recognition that typically we operate under the assumption that no movement in the ankle of of a LE prosthesis. Minimal to no ankle articulation.

59

Are endoskeletal or exoskeletal prostheses more common?

vast majority are endoskeletal

60

What is the Contracture Effect?

Basically the reverse of the heel effect

have an amputee whose limb was designed in a little bit of knee flexion. They develop a knee flexure contracture (causes even more knee flexion than the original prosthesis was designed for), which changes the angle of the socket and the shank/pilon and foot are affected also (basically the reverse of the heel effect. It all moves together).

 

61

What is the assumption we make for the Contracture Effect?

assumption that there is no movement at the junction between the residual limb and a socket.

62

Somewhere that looks interesting to visit in Portland, Maine

Portland Museum of Art

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63

What is a TKA line?

In prosthetics GRF is called TKA line (Trochanter Knee Ankle line)

  • should be called the TA line (dr. mincer said TKA is not a good name)
  • Sort of like GRF (same principle in that if the TKA line is posterior to the knee, it creates a flexion moment). Usually it is bad to create a flexion moment.
  • So it is not really the same as GRF, it is always between the hip and ankle

**Dr. mincer said

64

If you google TKA, what will you discover also goes by this name?

Total knee arthroscopy

And, it turns out the artificial knee joint placed during total knee arthroscopy is also called a prosthesis.

:-)

65

What did Dr. Mincer say is critical to think about? What knowledge can we apply here?

Energy Consumption is critical to think about

  • lighter components are a better choice
  • Transfemoral amputee takes more energy to ambulate than transtibial amputee
    • take that into account (comorbidities, etc)

66

Explain some things (3 ish) about movement between the socket and residual limb

Generally the less movement

  • you want the prosthesis to move with the residual limb
  • You want no movement between the RL and the prosthesis
    • think of running shoes with no laces that are 2 sizes too big
  • Friction is a problem if there is movement
    • vascular problems make this even worse
    • Don’t want pistoning

67

What is the function equation and what does it mean?

Function = stability + mobility

 

For Function you need stability, but also mobility

68

What is the stability equation (two parts of stability)

Overall Stability for the amputee has two parts

  • alignment stability
  • Dyamic stability

 

Overall Stability = Alignment Stability + Dynamic Stability

We want a balance between the two

69

Where does Alignment Stability come from?

Examples

Alignment Stability

  • comes from hardware
  • example: joint relationship to each other, hardware

70

Where does Dynamic Stability come from?

Examples

Dynamic Stability

  • comes from pt muscles
  • Example: quads to prevent knee buckling

71

If an amputee is very strong, should we ignore static stability?

Even if amputee is very strong (dynamic stability), hardware should still optimize alignment stability for the sake of energy expenditure. Too much dependance of alignment stability may also cause increased energy expenditure because of compensations.

72

Is a long residual limb or short residual limb better?

Why?

Long residual limb is better because of leverage

  • she also said it would result in smaller/shorter prosthesis (but in a later class, she said that the socket would still come up all they way to the poplitial fossa, so be careful with this statement)
  • Surgeons try to leave as much as possible
    • vascular problem amputee (must cut to tissue they believe is able to heal)

73

What are the most important muscles for pts with transtibial amuptations?

Transtibial: Quads are most important muscles

74

What are the most important muscles for pts with transfemoral amuptation?

Transfemoral: Hip flexors are most important muscles (don’t have quads)

may wrap quads to be able to use a bit of rectus femoris

75

Skin/Socket Interface:

Where could you put socks when using a:

  • Hard socket only
  • Nylon sheath
  • Soft Insert
  • Gel Liner
  • Fleixble Socket
  • Expandable wall socket

Socks:

  • When using only hard socket: Skin --> sock --> hard wall (socket)
  • When using nylon sheath: skin--> sheath --> sock --> socket
  • When using Soft Insert: skin --> sheath/sock --> soft insert --> hard socket
  • When using Gel Liner: Skin --> gel liner/liner liner (type of sheath) --> sock --> hard socket
  • When using Fleixble Socket: still trying to undetstand what a flexible socket is?
  • When using an expandable wall socket: not sure here either? (likely the same as when using a soft insert)

**add/remove ply for thickness/correct fit

**socks are somewhat optional for most of these (if you don't need to add thickness, don't add the sock)

 

76

Skin/Socket Interface:

When using only a hard socket, what would you put between the skin and the hard socket, and in what order would you layer it?

When using only hard socket:

  • Skin --> sock --> hard wall (socket)

77

Skin/Socket Interface:

When using a nylon sheath, what would you put between the skin and the hard socket, and in what order would you layer it?

When using nylon sheath:

  • skin--> sheath --> sock --> socket

**can also use a sheath with a gel liner:

  • Skin --> gel liner/liner liner (type of sheath) --> sock --> hard socket

78

Skin/Socket Interface:

When using a soft insert, what would you put between the skin and the hard socket, and in what order would you layer it?

When using Soft Insert:

  • skin --> sheath/sock --> soft insert --> hard socket

79

Skin/Socket Interface:

When using a gel liner, what would you put between the skin and the hard socket, and in what order would you layer it?

When using Gel Liner:

  • Skin --> gel liner/liner liner (type of sheath) --> sock --> hard socket

80

Skin/Socket Interface:

When using a flexible socket, what would you put between the skin and the hard socket, and in what order would you layer it?

When using Fleixble Socket:

  • still trying to undetstand what a flexible socket is? ( am guessing it would be skin --> sheath/sock --> flexible socket (with outer hard socket incorporated into it)

 

81

Skin/Socket Interface:

When using an expandable wall socket, what would you put between the skin and the hard socket, and in what order would you layer it?

When using an expandable wall socket:

  • not sure here either? (likely the same as when using a soft insert: skin --> sheath/sock --> expandable wall socket --> hard socket)